tag:theconversation.com,2011:/us/topics/crustaceans-14233/articlesCrustaceans – The Conversation2023-12-05T13:19:21Ztag:theconversation.com,2011:article/2180082023-12-05T13:19:21Z2023-12-05T13:19:21ZHow a thumb-sized climate migrant with a giant crab claw is disrupting the Northeast’s Great Marsh ecosystem<figure><img src="https://images.theconversation.com/files/560052/original/file-20231116-28-pkwiiq.JPG?ixlib=rb-1.1.0&rect=83%2C832%2C3233%2C2161&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Male fiddler crabs are small, with one oversized claw.</span> <span class="attribution"><span class="source">David S. Johnson</span></span></figcaption></figure><p>Nine years ago, I stood on the muddy banks of <a href="https://www.mass.gov/info-details/great-marsh-acec">the Great Marsh</a>, a salt marsh an hour north of Boston, and pulled a thumb-sized crab with an absurdly large claw out of a burrow. I was looking at a fiddler crab – a species that wasn’t supposed to be north of Cape Cod, let alone north of Boston.</p>
<p>As it turned out, the marsh I was standing in would never be the same. I was witnessing climate change in action.</p>
<p>The Great Marsh is on the Gulf of Maine, the piece of the Atlantic that extends approximately from Cape Cod, Massachusetts, to Nova Scotia, Canada. The marshes along the gulf are <a href="https://www.massaudubon.org/our-work/birds-wildlife/bird-conservation-research/massachusetts-important-bird-areas/iba-sites/great-marsh">critical breeding sites</a> for many bird species. But the water there is warming faster than almost <a href="https://doi.org/10.1126/science.aac9819">anywhere else on the planet</a>. And with warming water comes warm-water species.</p>
<figure class="align-center ">
<img alt="A view of a marsh with grasses growing along a creek at sunset." src="https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560051/original/file-20231116-19-nva80e.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Marsh grass is essential for both habitat and adapting to sea-level rise in the Great Marsh.</span>
<span class="attribution"><span class="source">David S. Johnson</span></span>
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<p><a href="https://theconversation.com/climate-change-is-already-disrupting-us-forests-and-coasts-heres-what-were-seeing-at-5-long-term-research-sites-164906">Maryland blue crab</a> and <a href="https://doi.org/10.1093/icesjms/fsu217">black sea bass</a>, both southern species, are now being caught in <a href="https://www.manomet.org/bluecrab/">Maine lobster traps</a>. And fiddler crabs, whose charismatic males have oversized claws to attract mates and defend against rivals, <a href="https://doi.org/10.1002/ecy.4203">are marching up the Eastern Seaboard</a>.</p>
<p>This rapid migration is due, in part, to their young. While adult fiddler crabs scuttle on the mud, their young swim in the water and are carried by the currents. Warming waters allow them to complete their life cycle, and currents carry the next generation farther north.</p>
<p>As a <a href="https://www.vims.edu/about/directory/faculty/johnson_d.php">marine ecologist who has worked in the Great Marsh for decades and studies climate migrants</a> – species that have shifted or expanded their ranges due to climate change – I want to know how these migrations affect the ecosystems they move into. I was surprised to find fiddler crabs in the Great Marsh, but I was more surprised by how they affected the marsh.</p>
<figure class="align-center ">
<img alt="A canal through a marsh, with boats on it." src="https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=599&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=599&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560214/original/file-20231117-19-z9lafq.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=599&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Rowley River in Rowley, Mass., at low tide in the Great Marsh. Marshes are critical for recreational and commercial activities such as clamming, fishing, boating and birding.</span>
<span class="attribution"><span class="source">David S. Johnson</span></span>
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<h2>Fiddler friend turns foe</h2>
<p>Salt marshes are grasslands flooded daily by the sea. Imagine a Midwest prairie as oceanfront property.</p>
<p>South of Cape Cod, decades of research has shown that when fiddler crabs are present, <a href="https://doi.org/10.2307/1940564">grass is more productive</a>. Fiddler-crab poop and burrows release nutrients and fuel plant growth. They are the earthworms of the salt marsh – they help plants grow.</p>
<p>But in the Great Marsh, <a href="https://doi.org/10.1002/ecy.4203">it isn’t working that way</a>.</p>
<p>Digging by fiddler crabs reduced the biomass of shoots and leaves in the Great Marsh by 40% and roots by 30% over the <a href="https://doi.org/10.1002/ecy.4203">course of the summers of 2020 and 2021</a>. That’s the opposite of what we would predict for summer growth.</p>
<p>I was surprised because the crabs were coexisting with the same plant species, <em><a href="https://gobotany.nativeplanttrust.org/species/spartina/alterniflora/">Spartina alterniflora</a></em>, in the Great Marsh as they were south of Cape Cod.</p>
<p><iframe id="ICMoY" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/ICMoY/11/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Why the different impacts? One reason is that while they may be the same species, these plants haven’t evolved with fiddler crabs as their southern kin have. Fiddler crabs don’t eat the grass, but when they dig, they damage <em>Spartina’s</em> roots. Plants in southern areas have adapted to this damage and now benefit from it, but plants in the North have yet to adapt. </p>
<h2>A chain reaction through the ecosystem</h2>
<p>The harm from this disruption can go well beyond the grasses to affect the rest of the Great Marsh food web.</p>
<p>Insects, spiders, snails and small crustaceans all rely on the grasses for food. These animals, in turn, are food for fish, shrimp and crabs. Less plant biomass could lead to <a href="https://doi.org/10.1007/s10021-018-0265-x">fewer fish</a> and shrimp. The <a href="https://www.massaudubon.org/our-work/birds-wildlife/bird-conservation-research/massachusetts-important-bird-areas/iba-sites/great-marsh">many birds that breed</a> in the marsh and stop there during migration rely on that food web.</p>
<p>Will this harmful relationship with crabs last forever for the plants? Probably not. <em>Spartina</em> has been able to <a href="https://doi.org/10.1111/nph.16371">adapt to new conditions within decades</a>. Plants in the Great Marsh, and the rest of the Gulf of Maine, will likely adapt to the fiddler’s presence over time, too.</p>
<p>In the meantime, however, fiddler crabs may magnify the impacts of climate change in the area.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman in a US Fish and Wildfire uniform kneels beside a ditch in the marsh." src="https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560060/original/file-20231116-23-ed38g1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nancy Pau, a wildlife biologist at Parker River National Wildlife Refuge, north of Boston, points to salt marsh grasses, which are essential for building up soil to help marshes survive sea-level rise.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usfwsnortheast/14441512407/in/photolist-o19wve">Margie Brenner/USFWS</a></span>
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</figure>
<p>Accelerated sea level rise driven by warming temperatures already <a href="https://doi.org/10.1002/lno.11444">threatens to drown the Great Marsh</a>. Salt marshes have kept pace with sea-level rise for millennia the same way you might deal with rising water threatening your house – by building up. Plants build marshes by trapping sediment brought in with each tide. Less grass could mean less marsh, and the marsh could drown.</p>
<p>Fiddler crabs also reduce the Great Marsh’s <a href="https://doi.org/10.3354/meps08708">ability to store carbon</a>. Salt marshes are giant compost piles that take centuries to rot, if ever. Every gardener knows that temperature and oxygen get a compost pile cooking. This is why you turn your compost.</p>
<p>Each year, dead plant roots are buried in soils with no oxygen. As a result, decomposition is greatly slowed, allowing the “compost” and carbon to build up and be stored. Because of this, salt marshes are <a href="https://oceanservice.noaa.gov/ecosystems/coastal-blue-carbon">critical as places that store carbon</a>, keeping it out of the atmosphere where it would contribute to climate change. However, burrows from fiddler crabs stimulate decomposition. The dead plants begin to rot, and carbon, once buried, is released.</p>
<h2>Climate migrants are found worldwide</h2>
<p>Fiddler crabs are just one of thousands of climate migrants we’ve seen worldwide. While ecosystems will adapt as climate migrants arrive, they will likely never be the same.</p>
<p>In Australia, when an herbivorous sea urchin expanded its range south, <a href="https://doi.org/10.1007/s00442-008-1043-9">plant and animal diversity plummeted after kelp forests were stripped bare</a>. In California, a predatory nudibranch (aka a sea slug) reduced the <a href="https://doi.org/10.1007/s00227-011-1633-7">local population of other nudibranchs</a> when it migrated north. In Antarctica, krill <a href="https://www.vims.edu/research/topics/global_change/ts_archive/krill_range.php">are shifting south</a>. Krill are the primary diet for whales, penguins and seals, so this shift could disrupt the Antarctic food web.</p>
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<img alt="A krill swims through dark water off Antarctica feasting on phytolankton." src="https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560229/original/file-20231118-24-fcrm6q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shrimplike krill are essential food for many species, including whales. They make up about a quarter of the Gentoo penguin’s diet in Antarctica.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/106398176@N07/10544282175/">Beth Simmons/Palmer Station LTER</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But it’s not always bad news when climate migrants show up.</p>
<p>When mangroves replace marshes in the southern United States, they <a href="https://doi.org/10.1111/1365-2745.12571">store more carbon</a>. Climate migrants can also benefit fisheries.</p>
<p>My lab studies the blue crab, famous in the Chesapeake Bay, which generated over <a href="https://www.fisheries.noaa.gov/foss/f?p=215:200:409148916679:Mail::::">US$200 million in dockside landings in 2022</a>. Now that blue crabs are <a href="https://theconversation.com/climate-change-is-already-disrupting-us-forests-and-coasts-heres-what-were-seeing-at-5-long-term-research-sites-164906">being found in lobster pots in Maine</a>, a fishery could be developed in northern Massachusetts, New Hampshire and Maine. However, it’s unknown how blue crabs and lobsters will get along.</p>
<p>In Virginia, warming waters have brought <a href="https://doi.org/10.1002/mcf2.10143">an abundance of white shrimp</a> along with <a href="https://www.bayjournal.com/news/climate_change/warm-temperatures-move-more-shrimp-into-chesapeake-waters/article_e55ea8ca-5479-11ec-a1c3-4f6085190504.html">a new fishery</a>. To the delight of anglers, the snook – a fun sportfish – has <a href="https://doi.org/10.1371/journal.pone.0234083">expanded into the Big Bend of Florida in the Gulf of Mexico</a>.</p>
<h2>More migration is still to come</h2>
<p>The year 2023 set a record for heat waves <a href="https://climatereanalyzer.org/clim/sst_daily/">in the world’s oceans</a>, and with greenhouse gases emissions still rising, <a href="https://nca2023.globalchange.gov/">warming will continue</a>. </p>
<p>While climate migrants are not considered invasive species, they can change ecosystems, as we’re already seeing in the Great Marsh. It’s important to understand how that happens, and whether ecosystems can adapt as species continue to change their ZIP codes.</p><img src="https://counter.theconversation.com/content/218008/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David S. Johnson receives funding from the National Science Foundation.. </span></em></p>South of Cape Cod, fiddler crabs and marsh grass have long had a mutually beneficial relationship. It’s a different story in the North, where the harms can ricochet through ecosystems.David Samuel Johnson, Associate Professor of Marine Sciences, Virginia Institute of Marine ScienceLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2178562023-11-21T21:53:50Z2023-11-21T21:53:50ZOxygen in the St. Lawrence Estuary is decreasing – and having a major impact on small animals living there<figure><img src="https://images.theconversation.com/files/559651/original/file-20231025-23-oo8vam.jpeg?ixlib=rb-1.1.0&rect=24%2C0%2C4001%2C2752&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The majestic St. Lawrence River, a jewel of economic, historical and environmental importance, reminds us of the need to preserve this essential ecosystem.</span> <span class="attribution"><span class="source">(Ludovic Pascal)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>The waters of the St. Lawrence Estuary are running out of breath. The lack of oxygen in deep waters is affecting the organisms that live on the bottom of the estuary.</p>
<p>How do deep ecosystems react to this deoxygenation?</p>
<p>In a previous article, we highlighted the <a href="https://theconversation.com/why-the-st-lawrence-estuary-is-running-out-of-breath-184626">causes of the decrease in the concentration of oxygen in the bottom waters of the estuary and Gulf of St. Lawrence</a>. This phenomenon, called hypoxia, is intensifying in this environment. In this article, we look at the impacts of low oxygen levels on the organisms that live at the bottom of the estuary and the Gulf of St. Lawrence, and on the overall functioning of this ecosystem.</p>
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<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
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<h2>The seabed, an environment teeming with life</h2>
<p>A large number of organisms live at the very bottom of the oceans. These are known as <a href="https://theconversation.com/discover-6-fascinating-animals-that-live-at-the-bottom-of-the-st-lawrence-river-215977">benthic organisms</a>. </p>
<p>This group of small animals includes starfish, worms, crustaceans and molluscs. They colonize the surface of the sediment (known as epifauna; “epi” for “on,” and “fauna” for “animal”) or burrow into the sediment (known as endofauna; “endo” for “inside”). </p>
<p>These organisms are not very mobile and cannot travel great distances.</p>
<h2>Bioturbation or the art of mixing sediment</h2>
<p>Benthic organisms don’t move around much, but they are far from being useless. On the contrary, they play a crucial role in the functioning of benthic ecosystems, through bioturbation. </p>
<p><a href="https://doi.org/10.3354/meps09506">Bioturbation</a> refers to all the activities that benthic organisms carry out, both on, and in sediments. Bioturbation can be compared to what earthworms do in our gardens: they dig burrows, mix grains of sediment and inject water containing oxygen into areas of the sediment that lack it. </p>
<p>Benthic organisms are therefore the “gardeners” of the ocean floor. And they help to maintain a healthy ecosystem. By bringing oxygen into the sediments, bioturbation allows many organisms to establish themselves there. It also increases biodiversity and promotes the decomposition of organic matter while <a href="https://doi.org/10.1007/s00227-019-3597-y">reducing the concentration of potentially toxic waste, such as hydrogen sulphide</a>.</p>
<h2>Oxygen and bioturbation: a not-so-simple relationship</h2>
<p>Twenty years ago, researchers used <a href="https://doi.org/10.4319/lo.2007.52.6.2555">models to try to predict the consequences of deoxygenation on the ecosystems of the bottom of the St. Lawrence</a>. Their work highlighted a critical element in anticipating future changes: how bioturbation responds to oxygen depletion.</p>
<p>Deoxygenation can lead to several types of responses in ecosystems. In a linear response scenario, the intensity of bioturbation decreases gradually and proportionally with the decrease in oxygen concentration. In such cases, it is relatively simple to predict the consequences, as the relationship is predictable. </p>
<p>However, there is another type of response that is non-linear and characterized by a threshold effect. This means that there is a certain critical point, a threshold, at which responses change abruptly. Before this threshold, the responses differ from those observed afterwards. These non-linear responses are associated with the development of resistance (or compensatory) mechanisms. These mechanisms operate at the level of the individual, the population (the set of individuals of the same species in a given location) and/or the community (the set of populations in a given location). They compensate for the effects of a disturbance until they are no longer sufficient. It is these compensatory mechanisms that make it difficult to predict the consequences of a disturbance.</p>
<h2>A non-linear relationship</h2>
<p>Our team has been studying the deoxygenation of the St. Lawrence for more than 20 years, but we had never before observed a clear relationship between the bioturbation of communities of benthic organisms and oxygen concentrations.</p>
<p>This raises an important question: does bioturbation respond in a linear or non-linear way to oxygen depletion? And is this a predictable relationship?</p>
<p><a href="https://doi.org/10.5194/bg-20-839-2023">The recent fall in oxygen concentrations in the bottom waters of the St. Lawrence</a> has enabled us to answer this question by observing a threshold effect for the first time. <a href="https://doi.org/10.1111/gcb.16994">We now know that the relationship between oxygen concentration and the functioning of benthic ecosystems is not linear</a>. </p>
<p>In other words, these ecosystems can resist deoxygenation up to a certain critical threshold, which is observed at an oxygen concentration of around 60 micromolar (i.e. approximately 20 per cent saturation, or 20 per cent of what the dissolved oxygen concentration should be if the water were in equilibrium with the atmosphere). This concentration is close to the value above which we speak of hypoxia. Below this threshold, communities of benthic organisms change, but surprisingly, without any significant loss of biodiversity. </p>
<p>However, the organisms that make up these communities are much less active. They are actually running out of air! They considerably reduce their movements, move towards the surface of the sediment and the intensity of bioturbation becomes practically zero. </p>
<p>In other words, in these conditions of severe hypoxia, the organisms no longer have enough energy to mix and irrigate the sediment.</p>
<h2>When bioturbation stops, what happens?</h2>
<p>These results have major implications for the role of sediments in the overall health of ecosystems in the estuary and Gulf of St. Lawrence. When bioturbation stops, the sediments are neither mixed nor irrigated efficiently, leading to the accumulation of toxic waste very close to the surface of the sediment. </p>
<p>As this waste accumulates, it could even spread into the water column, scaring away sensitive species and increasing deoxygenation. </p>
<p>When and under what conditions would this happen? This is the question we now need to answer. </p>
<p>Deoxygenation of the bottom waters of the St. Lawrence is of particular concern because it is likely to lead to changes in the abundance and distribution of fishery resources. Indirectly, therefore, it could have socio-economic effects that have yet to be fully assessed.</p><img src="https://counter.theconversation.com/content/217856/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ludovic Pascal is a member of the Québec Océan inter-institutional group and the Nereis Park scientific association. He has received funding from the FRQNT, the MEOPAR Network of Centres of Excellence, and the Québec government (Réseau Québec Maritime, MEIE, MELCCFP).</span></em></p><p class="fine-print"><em><span>Gwénaëlle Chaillou has received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC), Fonds de Recherche du Québec, Canada Research Chairs, and the Government of Québec (Réseau Québec Maritime, MEIE, MELCCFP). She is a member of the Québec Océan inter-institutional group, ACFAS, the Geochemical Society and the International Association of Hydrogeologists - Canadian National Committee (IAH-CNC).</span></em></p>The waters of the St. Lawrence are running out of breath and bottom-dwelling organisms are already feeling the effects. Here’s how ecosystems are reacting.Ludovic Pascal, Postdoctorant en biogéochimie marine, Université du Québec à Rimouski (UQAR)Gwénaëlle Chaillou, Professeure de chimie marine à l'Institut des sciences de la mer de Rimouski (ISMER-UQAR), Université du Québec à Rimouski (UQAR)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2158442023-11-16T10:40:17Z2023-11-16T10:40:17ZWhy the Pyrenees’ mountain lakes are turning green<figure><img src="https://images.theconversation.com/files/554285/original/file-20230921-21-xzmfew.jpg?ixlib=rb-1.1.0&rect=39%2C63%2C5232%2C3880&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Ayès lake, in the Ariège region of the Pyrenees.</span> <span class="attribution"><span class="source">Dirk S. Schmeller</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>I first set foot <a href="https://theconversation.com/pourquoi-le-rechauffement-climatique-saccelere-dans-les-pyrenees-173362">in the Pyrenees</a> in 2006. Two years later, I began a large-scale survey of mountain lakes and amphibian populations: from east to west, I covered more than 100 mountain lakes located in the eastern Pyrenees to the Béarn region (Pyrénées-Atlantiques).</p>
<p>For our various projects, we came back to sample the same lakes at least once a year. Over time, we noticed changes, in particular the increased growth of algae <a href="https://theconversation.com/dans-les-eaux-de-baignade-les-cyanobacteries-amies-ou-ennemies-204352">cyanobacteria</a> and sometimes dinoflagellates, the blue-green algae that turn many lakes green. Back in 2012, we informed the Pyrenees National Park (PNP) about our observations.</p>
<p>Over the years, I’ve seen many of these lakes change colour. Some have lost the clarity and blue we’ve all come to expect from a mountain lake, while others have started to take on a greenish hue or even a bright green, particularly at the end of summer.</p>
<p>This trend does not affect any one region more than another: it can be found in the Ariège Pyrenees, the central mountains of the Pyrenees, as well as the western Béarn region. This is not a rare, localised phenomenon, but a large-scale event that is set to spread over the coming years. We’re also seeing it on the other side of the border, in the Catalan Pyrenees, where my colleague Marc Ventura has been leading the <a href="http://www.lifelimnopirineus.eu/es/inicio">European Limnopirineus project</a>.</p>
<p>In the Alps, colleagues at the research centre for high-altitude ecosystems (<a href="https://creamontblanc.org/">in French: Centre de recherche des écosystèmes d’altitude, Crea</a>) have made a similar observation. Even in the <a href="https://www.nps.gov/articles/algal-booms-mountain-lakes.htm">Canadian Rockies</a>, a clear growth in algae has been observed.</p>
<p>We have identified four main causes of this greening of the lakes.</p>
<h2>1. More fish and algae, fewer crustaceans</h2>
<p>On the Catalan side, Marc Ventura first noticed that the presence of fish was contributing to the phenomenon, and that their eradication was turning the lakes back to a bluish hue. For those of you who might have a problem with the idea of “eradication”, it should be pointed out that the presence of fish in mountain lakes is not natural: it is the result of fish stocking carried out to promote recreational fishing.</p>
<p>To better understand the mechanisms at work, it is important to realise that the species present in mountain lake communities form a highly complex system, with a bewildering number of interactions. The disappearance of one species or a group of species from an aquatic system can lead to radical changes of the overall ecosystem (in this case, a mountain lake).</p>
<p>In the lakes studied, for example, it was observed that crustaceans were much less numerous or even absent in the presence of fish, particularly minnows, a very commonly introduced species in mountain lakes. Microcrustaceans in aquatic ecosystems filter water to ingest food, which is essentially made up of algae: in their absence, this imbalance allows algae to proliferate.</p>
<h2>2. Insecticides that kill crustaceans</h2>
<p>According to our <a href="https://theconversation.com/pyrenees-francaises-un-cocktail-toxique-impressionnant-detecte-dans-les-lacs-de-montagne-181860">own work</a> carried out in certain lakes, the absence or sharp reduction in crustaceans is also due to pollution. It is thought two insecticides in particular shoulder the blame: <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969722015492">permethrin and diazinon</a>, which are either used on livestock to protect them from stinging insects or are present in insect repellents used by tourists.</p>
<p>We have identified many other chemical molecules in lake water – <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969722015492">141 in total</a> – and the effect of this cocktail on aquatic food webs is currently unknown. It should be noted, however, that we are currently only able to detect a small proportion of the organic molecules, due to methodological limitations. The cumulative toxicity of all the pollutants emitted by humans in these environments therefore remains a mystery.</p>
<p>It is therefore likely that we are underestimating the overall impact of the large number of organic molecules on aquatic ecosystems in the mountains and elsewhere. But there is no doubt that, in the lakes we are studying, the increase in pollution is encouraging the disappearance of microcrustaceans and therefore the proliferation of algae.</p>
<h2>3. Livestock waste, nutrients for algae</h2>
<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969722015492">Research</a> has indicated pollutants may come from livestock, which are treated against biting insects with Butox or similar veterinary treatments containing deltamethrin or permethrin. Applied to the skin, these insecticides penetrate the animal’s bloodstream before being excreted in urine and faeces.</p>
<p>The active molecule remains largely unchanged and enters the water, even though it is <a href="https://enveurope.springeropen.com/articles/10.1186/s12302-022-00710-3">highly toxic to crustaceans in mountain lakes</a> starting from a concentration of the order of a few nanograms per litre, which is tiny. By killing crustaceans, these insecticides profoundly alter the aquatic food web.</p>
<p>But that’s not all. Algae also need nutrients to grow. Cattle provide them by drinking from lakes before urinating and defecating in the water: these discharges contain a high concentration of nutrients (nitrates and phosphates, among others), and especially phosphates are needed by cyanobacteria, filamentous algae.</p>
<h2>4. Climate change</h2>
<p>Finally, algae appreciate the heat: they multiply with high growth rates during the summer months, particularly when the water temperature exceeds 20°C. The rise in temperature caused by climate change is therefore adding to the other factors. In 2022, the edge of Lake Lhurs, in the Béarn region of France, reached over 25°C at an altitude of almost 1,800 metres – a blessing for algae.</p>
<p>These are the main factors, but my research could uncover more in the future. The most important thing is to understand that they act in synergy: we kill crustaceans by introducing fish, we pollute by treating livestock and then, once the mountain aquatic ecosystems have been weakened, we contribute through our activities to increasing the temperature of the lakes: algae then find the ideal conditions for growth. Some of these <a href="https://www.sciencedirect.com/science/article/pii/S0043135423009879">algae are toxic</a> and therefore present a health risk.</p>
<p>Our lakes thus change from blue to greenish, from greenish to bright green: no mystery to this, their colour simply reveals what we are inflicting on our mountain lakes, our water resources, wildlife, livestock and ourselves.</p>
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<figcaption><span class="caption">Mountain lake ecosystem health indicators (“Mountains, a fragile source of life”, 21 September 2023).</span></figcaption>
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<h2>How to get clear, blue lakes back</h2>
<p>Fortunately, all is not lost. The work of <a href="https://www.researchgate.net/publication/361705726_Non-native_minnows_cause_much_larger_negative_effects_than_trout_on_littoral_macroinvertebrates_of_high_mountain_lakes">Marc Ventura</a> highlights that it is still possible to turn back the clock and return lakes to a blue colour and healthy ecosystems. But this means changing the management of all the mountain lakes.</p>
<p>First, it is essential to limit fish stocking to certain large lakes and ban it in the others, so that they are reserved for local flora and fauna. Even in the large lakes, areas that are inaccessible to fish can be created to encourage invertebrates, amphibians and other aquatic and semi-aquatic species.</p>
<p>The next step is to reduce the pollution caused by tourists, livestock and industry. In particular, by communicating and discussing with the various stakeholders, alerting them to the risks and working with them to find real solutions rather than unsatisfactory compromises.</p>
<p>For example, the Ariège Pyrenees Regional Nature Park has begun to raise awareness among tourists, at least about the use of sun creams. This is a first step, albeit an insufficient one given the range of problems explained here. Another step forward would be to limit cattle access to mountain lakes, which would also help to restore the ecosystems. Finally, on a larger scale, the phenomenon is yet another reminder of the urgent need to combat climate change…</p>
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<img alt="" src="https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308798/original/file-20200107-123373-wmivra.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Created in 2007 to help accelerate and share scientific knowledge on key societal issues, the Axa Research Fund has supported nearly 700 projects around the world conducted by researchers in 38 countries. To learn more, visit the site of the Axa Research Fund or follow on Twitter @AXAResearchFund.</em></p>
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<p><em>The <a href="https://anr.fr/Projet-ANR-21-BIRE-0002">BiodivRestore</a> project is supported by the French National Research Agency (ANR), which funds project-based research in France. Its mission is to support and promote the development of fundamental and applied research in all disciplines, and to strengthen the dialogue between science and society. For more information, visit the <a href="https://anr.fr/">ANR website</a>.</em></p><img src="https://counter.theconversation.com/content/215844/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dirk S. Schmeller has received funding from the ANR and AXA Research Fund.</span></em></p>Many mountain lakes in the Pyrenees have turned green, a phenomenon that is a warning about the multiple pressures on ecosystems.Dirk S. Schmeller, Directeur de recherche CNRS, Expert for Conservation Biology, Axa Chair for Functional Mountain Ecology at the École Nationale Supérieure Agronomique de Toulouse, Centre national de la recherche scientifique (CNRS)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2119022023-09-04T20:06:03Z2023-09-04T20:06:03ZMarine heatwaves don’t just hit coral reefs. They can cause chaos on the seafloor<figure><img src="https://images.theconversation.com/files/545458/original/file-20230830-15-tabdkd.jpg?ixlib=rb-1.1.0&rect=0%2C407%2C3888%2C2479&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Most of us know what a heatwave feels like on land – sweltering heat for days. But oceans get heatwaves too. When water temperature goes over a seasonal threshold for five days or more, that’s a marine heatwave. They do their worst damage in summer, when the ocean is already at its warmest, but they can occur any time of year. </p>
<p>Over 90% of the heat trapped by greenhouse gases has <a href="https://climate.nasa.gov/vital-signs/ocean-warming/#:%7E:text=Covering%20more%20than%2070%25%20of,heat%20as%20Earth's%20entire%20atmosphere.">gone into</a> our oceans. So it’s no surprise marine heatwaves are getting much more intense and more frequent. This year has been off the charts. From April this year, the world’s average ocean temperature <a href="https://climatereanalyzer.org/clim/sst_daily/">has been</a> the highest ever recorded. </p>
<p>Since the 1980s, satellites have revolutionised ocean science by making it possible to take daily measurements of ocean temperatures. But satellites watch from above. They can’t see what’s happening below the surface. </p>
<p>Our <a href="https://doi.org/10.1038/s43247-023-00966-4">new research</a> explores what’s happening in deeper waters. It turns out, marine heatwaves aren’t just on the surface. In the most devastating marine heatwaves, heat can penetrate right down to the sea bed. Remarkably, some heatwaves only affect the seafloor. </p>
<h2>Why do deep marine heatwaves matter?</h2>
<p>While we usually only see sea creatures at the surface of the ocean, there’s life all the way down. In the shallower seafloors of the continental shelf – the sunken parts of our continents – live fish, kelp beds, sponges, cold water corals, shellfish and crustaceans. </p>
<p>These shallow oceans are, on average, less than 100 metres deep. When the shelf ends, there’s usually an abrupt slope into the deep ocean, where there are kilometres of water between surface and seabed. </p>
<p>Marine heatwaves are damaging to life in the seas covering the continental shelf. Creatures here are sensitive to extreme temperatures, just like those at the surface. But “extreme” to them is different to what we think of as extreme. If you’re used to water at 12°C, a heatwave of 15°C can be devastating. </p>
<p>When marine heatwaves strike, they can kill. More than a billion sea creatures died during a <a href="https://www.nature.com/articles/s41467-023-36289-3">single heatwave</a> off the coast of the western United States and Canada in 2021. This year, extreme heatwaves have hit large parts of the oceans during the northern summer. </p>
<p>Fish and other creatures that can move do so, heading towards the poles or down deeper in search of cooler water. Those that can’t have to endure it or die. Heatwaves can trigger migration. New species arrive, seeking refuge and can alter the ecosystem. </p>
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Read more:
<a href="https://theconversation.com/an-extreme-heatwave-has-hit-the-seas-around-the-uk-and-ireland-heres-whats-going-on-208052">An 'extreme' heatwave has hit the seas around the UK and Ireland – here's what's going on</a>
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<h2>We don’t know much about deeper marine heatwaves</h2>
<p>The seas covering the continental shelf are relatively shallow compared to the kilometres of water in the deep oceans. But even so, it’s impossible to see what’s going on below using satellites or <a href="https://imos.org.au/facilities/oceanradar">high-frequency radar</a>. </p>
<p>The sea is a hostile environment. Instruments are subject to high pressure, corrosive salt water and marine organisms like oysters and sponges settling on them. This is one reason why we only have very limited data on long-term trends in temperatures under the surface. But these records are vital to calculate typical temperatures for the time of year and to figure out what constitutes an extreme. </p>
<p>Australia is one of the few places generating this kind of valuable data long-term. Off the coast of the southeast lie many oceanographic moorings – a floating <a href="https://imos.org.au/facilities/nationalmooringnetwork/">collection of sensors</a> anchored to the bottom. One of these has been measuring daily temperatures from the surface to the seafloor 65 metres down since 1993. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="oceanographic instrument" src="https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=853&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=853&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=853&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1072&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1072&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545276/original/file-20230829-19-lqlw60.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1072&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">In addition to coastal moorings, this oceanographic instrument also measures temperature and salinity of the ocean.</span>
<span class="attribution"><span class="source">Amandine Schaeffer</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Our earlier research found marine heatwaves at depth can actually be <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL073714">more intense</a> and <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL094785">last longer</a> compared to the surface. But why? </p>
<p>In our new research, we looked at the temperature data closely. We found marine heatwaves come in a variety of types and have different causes. We also found some types of marine heatwave are more likely during particular seasons. </p>
<p>For instance, winter marine heatwaves often run from surface to seafloor. They occur when the powerful, deep and warm East Australian Current snakes westward towards the coast. As the current swings over the continental slope, it drags warm water over the shelf and close to the coast. </p>
<p>In summer, Australia gets two very different types of heatwave in our oceans. The first occur when we get blue-sky weather. With few clouds, more heat from the sun gets into the oceans. They can also occur when there are weaker winds and less ocean cooling from evaporation. These heatwaves are confined to the surface and a few metres below. </p>
<p>Then there’s the second, a very weird heatwave system that only appears close to the seafloor. These are produced when strong wind creates currents driving warm, shallower water down to the bottom. On the east coast, these currents come from cold winds from the south. So even while you’re shivering through cold winds from the Southern Ocean, the ocean seafloor may be sweltering through a heatwave. These may be the most destructive to ecosystems but go all but unnoticed. </p>
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<figcaption>
<span class="caption">This figure shows the different types of marine heatwaves affecting coastal waters (shown by the anomalous heat in red)</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Marine heatwaves are not created equally</h2>
<p>Our research has shown marine heatwaves come in different flavours. That matters, because it will allow us to get better at predicting if a heatwave is about to strike our oceans. And it will let us anticipate which parts of the water column are about to be hit, and which ecosystems. </p>
<p>Of course, slowing ocean warming and preventing marine heatwaves from damaging ecosystems means slashing carbon emissions. But while we work on that, this knowledge could give us time to find strategies to reduce the undersea death toll – and the damage to tourism and fishing which rely on these ecosystems surviving. </p>
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Read more:
<a href="https://theconversation.com/coral-reefs-how-climate-change-threatens-the-hidden-diversity-of-marine-ecosystems-211007">Coral reefs: How climate change threatens the hidden diversity of marine ecosystems</a>
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<img src="https://counter.theconversation.com/content/211902/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amandine Schaeffer receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Alex Sen Gupta receives funding from the Australian Research Council</span></em></p><p class="fine-print"><em><span>Moninya Roughan receives funding from the Australian Research Council, and Australia’s Integrated Marine Observing System (IMOS) – IMOS is enabled by the National Collaborative Research Infrastructure Strategy (NCRIS).</span></em></p>Marine heatwaves aren’t just on the surface. They can be at their most destructive when they sweep along the seafloor.Amandine Schaeffer, Senior lecturer, UNSW SydneyAlex Sen Gupta, Senior Lecturer, School of Biological, Earth and Environmental Sciences, UNSW SydneyMoninya Roughan, Professor in Oceanography, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081162023-07-11T13:54:49Z2023-07-11T13:54:49ZOffshore windfarms could offer new habitats for lobsters – new research<figure><img src="https://images.theconversation.com/files/536584/original/file-20230710-25-qjfszb.jpg?ixlib=rb-1.1.0&rect=39%2C0%2C4344%2C2874&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The European lobster (Homarus gammarus)</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/european-lobster-homarus-gammarus-1182497287">Dave M Hunt Photography/Shutterstock</a></span></figcaption></figure><p>Over the past decade, offshore wind turbines have become an ever more present feature along UK coastlines. As part of reaching net zero, the <a href="https://researchbriefings.files.parliament.uk/documents/CBP-9783/CBP-9783.pdf">government has ambitious plans</a> for increasing the capacity of offshore wind from 13.9GW to 50GW by 2050.</p>
<p>Expanding the UK’s renewable energy sector is necessary to replace fossil fuels and meet increasing energy demands. But the rate at which offshore windfarm development is planned makes it difficult to understand the effect it will have on the marine environment and the people who rely on it for their livelihood. </p>
<p>To date, most offshore wind turbines have been built using fixed foundations. To protect the foundations from erosion, large deposits of rocks and boulders – called “scour protection” – are placed around the base of each turbine. This means that with each new windfarm, there is an increase in the amount of such material in the marine environment.</p>
<p><a href="https://academic.oup.com/icesjms/article/80/5/1410/7145793#409536204">Our new study</a> shows the European lobster is making use of the scour protection as shelter. The presence of this commercially important species within these sites suggests fishing opportunities may develop from future windfarm construction.</p>
<h2>The reef effect</h2>
<p>When offshore windfarms are constructed in sandy habitats, the addition of scour protection leads to a change in the type of habitat available to marine life. This may have knock-on effects for marine organisms such as allowing certain species to occupy areas they were not previously found.</p>
<p>This process is often referred to as the “<a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/artificial-reef">artificial reef</a> effect”. It is considered one the most important effects of offshore windfarm development. However, we have relatively little data to help us understand how species are interacting with scour protection within offshore windfarms, and what effects these might have on marine life and hence on local fishing industries.</p>
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<img alt="Wind turbines in the sea at dusk" src="https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536630/original/file-20230710-29-tvknt8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Most offshore wind turbines have been built using large deposits of rocks and boulders.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/offshore-wind-turbines-farm-sunset-1454940068">TebNad/Shutterstock</a></span>
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<p>We used acoustic telemetry, which is a widely used aquatic tracking method, to record the movements of 33 lobsters within an offshore windfarm in the Irish Sea. We found that they favoured residing in areas of scour protection. More than 50% of all our lobster detections were recorded within 35 metres of the scour protection. </p>
<p>Lobsters typically make use of crevices in rocks and reef as shelter and will return to the same crevices after feeding or other activities. We recorded the lobsters making frequent movements to and from the same areas of scour protection. Four months later, more than 50% of the lobsters were still present in the same areas of scour they were originally detected at. </p>
<p>We can’t be sure what the short excursions away from the scour protection mean. However, we believe our results highlight that the addition of scour protection within offshore windfarms is creating a habitat for lobsters. </p>
<h2>Increasing lobster populations</h2>
<p>Offshore engineering projects, including windfarm development, can harm the marine environment. For instance, electromagnetic fields and underwater noise generated as part of construction and operation may have detrimental effects on marine species. And as a result of taking up large marine areas, these developments affect existing marine-based industries, in particular small-scale commercial fisheries. </p>
<p>Our research has highlighted an opportunity to work towards lessening the potentially harmful effects of offshore engineering. If the scour protection already installed as part of offshore windfarm construction can support lobsters, then it is likely that increasing the volume of scour rocks (or modifying the type of scour), could work towards promoting increased lobster populations within offshore windfarms. </p>
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Read more:
<a href="https://theconversation.com/weve-discovered-why-some-whales-stop-feeding-in-response-to-the-sound-of-sonar-179541">We've discovered why some whales stop feeding in response to the sound of sonar</a>
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<p>This might help to increase ecological value and maximise fishing opportunities within these sites. There is potential that this could offset, to some extent, the disturbance to fishing areas. It could also compensate fishing communities that are negatively affected by offshore windfarm construction.</p>
<p>However, for us to minimise the effects of offshore windfarm development and maximise the potential benefits of creating new homes for lobsters, we need to study the topic further. We must discover the most suitable ways of increasing lobster populations using scour protection, such as the ideal boulder size to create crevices suitable for lobster shelter. We must also study the logistics of fishing within these sites. </p>
<p>We are now working alongside the fishing community of north Wales to investigate the abundance of lobsters within existing offshore windfarms. We are aiming to quantify and predict the potential fishing opportunities that may arise from offshore windfarm construction.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Harry Thatcher receives funding from the Department for Environment Food and Rural Affairs (DEFRA). </span></em></p><p class="fine-print"><em><span>David Wilcockson receives funding from the Department for Environment Food and Rural Affairs (DEFRA).</span></em></p>New research shows European lobsters are using the deposits of rocks and boulders at the base of wind turbines as shelter.Harry Thatcher, PhD Candidate, Department of Life Sciences, Aberystwyth UniversityDavid Wilcockson, Reader in Biological Sciences, Aberystwyth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2078142023-06-23T22:03:40Z2023-06-23T22:03:40ZFractured foundations: how Antarctica’s ‘landfast’ ice is dwindling and why that’s bad news<figure><img src="https://images.theconversation.com/files/532866/original/file-20230620-29-tpniz5.jpg?ixlib=rb-1.1.0&rect=34%2C0%2C3888%2C1862&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Landfast ice 'breaks out'</span> <span class="attribution"><span class="source"> Justin Chambers/AAD</span>, <span class="license">Author provided</span></span></figcaption></figure><p>There’s more to Antarctic ice than meets the eye. Sea ice is not a uniform crust overlying the salty Southern Ocean. </p>
<p>Our <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022RG000770">new research</a> is the first to review the many crucial roles of <a href="https://www.antarctica.gov.au/about-antarctica/ice-and-atmosphere/sea-ice/fast-ice/">“landfast” sea ice</a> around Antarctica. Landfast ice is frozen seawater that is fastened to the coast. It acts like a belt around the Antarctic coast, regulating the flow of ice shelves and glaciers into the sea. And it’s crucial habitat for Weddell seals and emperor penguins.</p>
<p>Satellites can easily estimate the horizontal extent of sea ice, but determining the type of ice is far more difficult. Our deeper analysis of satellite images reveals landfast sea ice extent declined to a record low of just 123,200 square km in March 2022. That’s well below the normal March range of 168,600-295,200 square km. </p>
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<a href="https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533616/original/file-20230623-17-3388jo.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Distribution of anomalies in Antarctic fast-ice extent in early-mid March 2022. Red shading indicates negative anomalies, with a value of -1.0 indicating a lack of fast ice in 2022, in a region that has had early-mid March fast-ice cover every year from 2000 to 2021. Inset (b) is a time series of early-mid March fast-ice extent from 2000 to 2022. (Source: Reviews of Geophysics, CC BY-NC)</span>
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<p>Much of the ice lost in 2022 had been present since 2000, when high-quality records began. If this trend persists, the consequences for the climate and for Southern Ocean ecosystems could be catastrophic. </p>
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Read more:
<a href="https://theconversation.com/antarcticas-heart-of-ice-has-skipped-a-beat-time-to-take-our-medicine-202729">Antarctica's heart of ice has skipped a beat. Time to take our medicine</a>
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<h2>Getting a grip on landfast ice</h2>
<p>Antarctic sea ice drives the circulation of the world’s oceans. The “overturning” circulation begins in Antarctica when very salty, dense brine (created as the ice forms) sinks to the bottom of the ocean. This “bottom water” spreads away from Antarctica to reach the northern hemisphere. </p>
<p>This crucial circulation is <a href="https://www.abc.net.au/news/2023-03-30/dramatic-south-ocean-circulation-changes-study/102154690">projected to slow due to glacial melt</a>, because the input of more buoyant fresh water dilutes the denser brine. This raises the spectre of a further slowing or worse, total shut down of deep ocean currents as in the disaster movie, “<a href="https://en.wikipedia.org/wiki/The_Day_After_Tomorrow">The Day After Tomorrow</a>”. We know concentrated regions of sea ice formation tend to occur next to landfast ice, so the changes we are seeing are likely to further reduce this deep ocean circulation.</p>
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Read more:
<a href="https://theconversation.com/torrents-of-antarctic-meltwater-are-slowing-the-currents-that-drive-our-vital-ocean-overturning-and-threaten-its-collapse-202108">Torrents of Antarctic meltwater are slowing the currents that drive our vital ocean 'overturning' – and threaten its collapse</a>
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<p>Global climate models are <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL086729">not particularly skilful</a> at reproducing the recent history of Antarctic sea ice, giving limited confidence in our ability to predict its future. There are many reasons for this, but one of the main ones is an overly simplistic representation of the sea ice. </p>
<p>Landfast sea ice is not represented in any global climate model. These models treat all sea ice as if it’s able to drift, whereas in reality up to 15% of ice should be held still by being anchored to land or grounded icebergs. </p>
<p>This is a big problem because, as our study reveals, if we don’t properly simulate it, we are likely to get all kinds of inaccurate flow-on effects, including an incorrect amount of sea ice (and hence dense water) produced by our models. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532851/original/file-20230620-51741-lvtx2f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Icebreaker Aurora Australis in landfast ice.</span>
<span class="attribution"><span class="source">Jan Lieser</span></span>
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<h2>Wildlife depends on landfast ice</h2>
<p>Landfast ice supports a unique community of algae, krill, small crustaceans called copepods, molluscs and fish. They are adapted to live within and below the ice where conditions are harsh. </p>
<p>These species form a complex food web around ice algae, using the ice as a nursery ground. Life within landfast ice requires wide-ranging survival strategies. Drastic changes could mean cascading effects on the entire food web.</p>
<p>Seals and penguins rely on this environment for resting, hunting and breeding. Emperor penguins have a unique approach to raising a family that requires stable ice, which only landfast ice can provide. Reduced ice extent, increased fragmentation and earlier breakup can lead to population declines of this iconic species. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533066/original/file-20230621-23-ivmc60.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Adélie penguins toboggan on landfast ice.</span>
<span class="attribution"><span class="source">Pat Wongpan</span></span>
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<h2>Deeper knowledge is crucial for climate forecasts</h2>
<p>Only a few areas of Antarctic landfast ice are regularly sampled. These areas are found near Antarctic research stations and are generally separated by thousands of kilometres of coast. </p>
<p>Additionally, scientists can often only safely collect sea ice cores from smooth ice thick enough to support people. So sampling is skewed to favour the unbroken crème brûlée-type crust over the shattered meringue of rough landfast ice.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532819/original/file-20230620-51741-xp3jyz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scientists traverse smooth landfast ice near Casey Station to reach a site where they collect ice cores.</span>
<span class="attribution"><span class="source">Matthew Corkill</span></span>
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<p>To better understand rough landfast ice and a slew of other poorly understood ice types, we need repeat ice core measurements along with more detailed satellite studies. We also need the capability to model each ice type accurately.</p>
<p>Our research has ensured landfast ice is earmarked for inclusion in the next iteration of our national climate model, which aims to better simulate the interactions between sea ice of all types and the Southern Ocean. Without this ability, we are missing a key ingredient in the recipe of Australia’s climate future.</p>
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Read more:
<a href="https://theconversation.com/record-low-antarctic-sea-ice-is-another-alarming-sign-the-oceans-role-as-climate-regulator-is-changing-204680">Record low Antarctic sea ice is another alarming sign the ocean's role as climate regulator is changing</a>
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<hr>
<img src="https://counter.theconversation.com/content/207814/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Fraser receives funding from the Australian Government via the Australian Antarctic Program Partnership and the Australian Research Council, as well as from the Antarctic Science Foundation.</span></em></p><p class="fine-print"><em><span>Christine Weldrick receives funding from the Australian Government via the Australian Antarctic Program Partnership. </span></em></p><p class="fine-print"><em><span>Laura Dalman receives funding from the Australian Government via the Australian Antarctic Program Partnership.</span></em></p><p class="fine-print"><em><span>Pat Wongpan receives funding from the Australian Government via the Australian Antarctic Program Partnership. </span></em></p><p class="fine-print"><em><span>Matthew Corkill does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>More trouble in Antarctica: the extent of frozen seawater fastened to the coast (called landfast ice) hit a record low in March 2022. If this trend persists, the consequences could be catastrophic.Alexander Fraser, Senior Researcher in Antarctic Remote Sensing, University of TasmaniaChristine Weldrick, Antarctic Marine Zooplankton Ecologist, University of TasmaniaLaura Dalman, PhD candidate, University of TasmaniaMatthew Corkill, PhD candidate, University of TasmaniaPat Wongpan, Quantitative Sea Ice Biogeochemist/Ecologist, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2071152023-06-22T20:06:47Z2023-06-22T20:06:47ZMarine species are being pushed towards the poles. From dugong to octopuses, here are 8 marine species you might spot in new places<figure><img src="https://images.theconversation.com/files/533370/original/file-20230622-47893-dsgdgu.jpg?ixlib=rb-1.1.0&rect=649%2C28%2C3040%2C2031&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>If you take a plunge in the sea this winter, you might notice it’s warmer than you expect. And if you’re fishing off Sydney and catch a tropical coral trout, you might wonder what’s going on. </p>
<p>The reason is simple: hotter water. The ocean has absorbed the vast majority of the extra heat trapped by carbon dioxide and other greenhouses gases. It’s no wonder heat in the oceans is building up rapidly – and this year is <a href="https://theconversation.com/ocean-heat-is-off-the-charts-heres-what-that-means-for-humans-and-ecosystems-around-the-world-207902">off the charts</a>. </p>
<p>That’s even without the likely arrival of El Niño, where the Pacific Ocean gets warmer than usual and affects weather all over the world. Our coastal waters <a href="http://www.bom.gov.au/oceanography/oceantemp/sst-outlook-map.shtml">are forecast</a> to be especially warm over the coming months, up to 2.5°C warmer than usual in many places.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533327/original/file-20230622-27-cqb9j1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=605&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Oceans around Australia are forecast to be much warmer than usual. SSTA stands for projected Sea Surface Temperature Anomaly, the difference between forecast ocean temperatures and a historical baseline period encompassing 1990–2012.</span>
<span class="attribution"><span class="source">Bureau of Meteorology</span></span>
</figcaption>
</figure>
<p>Many marine species live within a narrow temperature range. If the water heats up, they have to move, and if they don’t, they might die. So those that can move, are moving. In Australia, at least 200 marine species have <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15634">shifted distributions</a> since 2003, with 87% heading south. </p>
<p>This pattern is happening all around the world, both on land and <a href="https://theconversation.com/thousands-of-photos-captured-by-everyday-australians-reveal-the-secrets-of-our-marine-life-as-oceans-warm-189231">in the ocean</a>. This year, the warmer ocean temperatures during winter mean Australia’s seascapes are likely to be more like summer. So, the next time you go fishing or diving or beachcombing, keep your eyes peeled and your camera ready. You may glimpse the enormous disruption happening underwater for yourself. </p>
<h2>Here are eight species on the move</h2>
<p><strong>1. Moorish idol (<em>Zanclus cornutus</em>)</strong></p>
<p>Historic range: northern Australia </p>
<p>Now: This <a href="https://www.redmap.org.au/species/1/204/">striking fish</a> can now be seen south of Geraldton in Western Australia and Eden in New South Wales. </p>
<p>This is a great fish for divers to spot on hard-bottomed habitats. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="moorish idol" src="https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533373/original/file-20230622-21-6g6xk8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Moorish Idols are heading south to escape the heat.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p><strong>2. Branching coral (<em>Pocillopora aliciae</em>)</strong></p>
<p>Historic range: northern NSW</p>
<p>Now: Look out for this <a href="https://www.redmap.org.au/species/2/255">pale pink beauty</a> south of Port Stephens, not far from Sydney.</p>
<p>Seemingly immovable species like coral are fleeing the heat too. They’re already providing habitat for a range of other shifting species like tropical fish and crab species. </p>
<p><strong>3. Eastern rock lobster (<em>Sagmariasus verreauxi</em>)</strong></p>
<p>Historic range: common in NSW </p>
<p>Now: South, as far as <a href="https://www.redmap.org.au/species/2/167">it can get.</a> It’s now found in Tasmania and even in <a href="https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/westward-range-expansion-of-the-eastern-rock-lobster-sagmariasus-verreauxi-in-australia/8DE945E58E1DDA1A2BB7431065AAC8EC">South Australia</a>. </p>
<p>This tasty greenish crustacean <a href="https://www.int-res.com/abstracts/meps/v624/p1-11/">doesn’t like heat</a> and has moved south into the territory of red southern rock lobsters (<em>Jasus edwardsii</em>). </p>
<p><strong>4. Gloomy octopus (<em>Octopus tetricus</em>)</strong></p>
<p>Previous range: common in NSW</p>
<p>Now: As far south as Tasmania. </p>
<p>Look out for this slippery, smart invertebrate in <a href="https://www.redmap.org.au/species/2/127">Tasmanian waters</a> this winter. You might even spot the octopus nestled down with some eggs, as this looks to be a <a href="https://www.publish.csiro.au/mf/mf14126">permanent sea change</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="gloomy octopus" src="https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=462&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=462&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=462&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=581&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=581&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533376/original/file-20230622-17-lf2y8r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=581&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The gloomy octopus is also known as the common Sydney octopus.</span>
<span class="attribution"><span class="source">Niki Hubbard, Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p><strong>5. Whitetip reef shark (<em>Triaenodon obesus</em>)</strong> </p>
<p>Previous range: northern Australia</p>
<p>Now: <a href="https://www.redmap.org.au/species/3/185">South of K'gari</a> (formerly known as Fraser Island). </p>
<p>Classed as vulnerable in parts of the world, this tropical shark is a slow swimmer and never sleeps. It poses very little danger to humans.</p>
<p><strong>6. Dugongs (<em>Dugong dugon</em>)</strong>
Previous range: northern Australia</p>
<p>Now: As far south as Shark Bay in WA and <a href="https://www.abc.net.au/news/2023-05-17/tweed-river-dugong-sighting-boaties-warned/102355438">Tweed River</a> in New South Wales. </p>
<p>Our waters are home to the largest number of dugong in the world. But as waters warm, they’re heading south. That means more of us may see these elusive sea-cows as they graze on seagrass meadows. </p>
<p>Some of the most adventurous have gone way out of their normal range – in 2014, a kitesurfer <a href="https://www.redmap.org.au/articles/2021/07/26/are-dugongs-hitching-a-ride-south/">reported</a> passing a dugong at City Beach, Perth. As a WA wildlife expert says, dugongs may occasionally stray further south of Shark Bay but “given the recent warming trend […] more dugong sightings might be expected in the future”</p>
<p><strong>7. Red emperor (<em>Lutjanus sebae</em>) and other warm water game fish</strong> </p>
<p>Previous range: northern Australia</p>
<p>Now: Appearing much further south – especially in WA. </p>
<p>Look for <a href="https://www.redmap.org.au/species/1/108/">red</a>, threadfin, and redthroat emperors in southwest WA as the Leeuwin current carries these <a href="https://www.redmap.org.au/articles/2021/07/26/game-fish-follow-warm-route-south/">warm water species</a> south. As WA fisheries expert Gary Jackson has said, this current is a warming hotspot, acting like a warm water highway for certain marine species.</p>
<p>These fish are highly <a href="https://goodfish.org.au/species/red-emperor/">sought after</a> by fishers. </p>
<p><strong>8. Long-spined sea urchin (<em>Centrostephanus rodgersii</em>)</strong></p>
<p>Historic range: NSW and Victoria</p>
<p>Now: Tasmania</p>
<p>Look out for these <a href="https://www.redmap.org.au/species/2/34/">spiky critters</a> in southern and western Tasmania. The larvae of these urchins have crossed the Bass Strait and found a new home, due to warming waters. Urchins are grazers and can scrape rocks clean, creating urchin barrens where nothing grows. That’s bad news for kelp forests and the species which depend on them. In response, Tasmanian authorities are working to create a <a href="https://fishing.tas.gov.au/community/long-spined-sea-urchin-management/long-spined-sea-urchin-strategy#:%7E:text=%E2%80%8B%E2%80%8B%E2%80%8BTackling%20the%20longspined%20sea%20urchin&text=Unchecked%2C%20the%20urchin's%20presence%20is,at%20around%2020%20million%20individuals.">viable urchin fishery</a> to keep numbers down.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="long spined sea urchins" src="https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533379/original/file-20230622-33216-7lslyr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Long-spiked sea urchins are voracious eaters of seaweed.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/johnwturnbull/32131133496/in/photostream/">John Turnbull/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sea-urchins-have-invaded-tasmania-and-victoria-but-we-cant-work-out-what-to-do-with-them-194534">Sea urchins have invaded Tasmania and Victoria, but we can’t work out what to do with them</a>
</strong>
</em>
</p>
<hr>
<h2>You can help keep watch</h2>
<p>For years, fishers, snorkellers, spearfishers and the general public have contributed their unusual marine sightings to <a href="https://www.redmap.org.au/">Redmap</a>, the Australian citizen science project aimed at mapping range extensions of species. </p>
<p>If you spot a creature that wouldn’t normally live in the waters near you, you can upload a photo to log your sighting. </p>
<p>For example, avid spearfisher Derrick Cruz logged a <a href="https://www.redmap.org.au/sightings/1624/">startling discovery</a> with Redmap in 2015: A coral trout in Sydney’s waters. As he told us: “I’ve seen plenty of coral trout in tropical waters, where they’re at home within the coral. But it was surreal to see one swimming through a kelp forest in the local waters off Sydney, much further south than I’ve ever seen that species before!”</p>
<p>How does tracking these movements help scientists? Many hands make light work. These vital observations from citizen scientists <a href="https://data-blog.gbif.org/post/gbif-citizen-science-data">have helped</a> researchers gain deeper understanding of what climate change is doing to the natural world in many places, from bird migrations to flowering plants to marine creatures. </p>
<p>So, please keep an eye out this year. The heat is on in our oceans, and that can mean sudden change. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sydneys-waters-could-be-tropical-in-decades-heres-the-bad-news-31523">Sydney's waters could be tropical in decades, here's the bad news...</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/207115/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gretta Pecl receives funding from the Australian Research Council, CSIRO, FRDC, DCCEEW, Department of Agriculture Water and the Environment, and Department of Primary Industries NSW.</span></em></p><p class="fine-print"><em><span>Curtis Champion receives funding from the Fisheries Research and Development Corporation. He works for NSW Department of Primary Industries.</span></em></p><p class="fine-print"><em><span>Zoe Doubleday receives funding from the Australian Research Council, Australian Academy of Science, and Fisheries Research and Development Corporation. </span></em></p>The world’s oceans are getting hotter, quicker. And our marine species are seeking cooler waters. Keep your eyes peeled and you might spot one of these species on the move.Gretta Pecl, Professor, ARC Future Fellow & Director of the Centre for Marine Socioecology, University of TasmaniaCurtis Champion, Research Scientist, Southern Cross UniversityZoe Doubleday, Marine Ecologist and ARC Future Fellow, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1957392022-12-06T11:08:04Z2022-12-06T11:08:04ZCrabs have evolved five separate times – why do the same forms keep appearing in nature?<figure><img src="https://images.theconversation.com/files/498528/original/file-20221201-14-gs16tp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Full size blue crab</span> </figcaption></figure><p>Charles Darwin believed evolution created “<a href="https://www.amnh.org/exhibitions/darwin/endless-forms-most-beautiful/from-so-simple-a-beginning">endless forms most beautiful</a>”. It’s a nice sentiment but it doesn’t explain why evolution keeps making crabs.</p>
<p>Scientists have long wondered whether there are <a href="https://www.42evolution.org/videos/researcher/professor-matthew-wills/">limits to what evolution can do</a> or if Darwin had the right idea. The truth may lie somewhere between the two.</p>
<p>While there doesn’t seem to be a ceiling on the number of species that might evolve, there may be restraints on how many fundamental forms those species can evolve into. The evolution of crab-like creatures may be one of the best examples of this, since they have evolved not just once but <a href="https://doi.org/10.1002/bies.202100020">at least five times</a>. </p>
<p>Crabs belong to a group of crustaceans called <a href="https://www.gbif.org/species/637">decapods</a> – literally “ten footed”, since they have five pairs of walking legs. Some decapods, like lobsters and shrimp, have a thick, muscular abdomen, which is the bulk of the animal that we eat. With a quick flick of their abdomen lobsters can shoot off backwards and escape predators. </p>
<p>Crabs, by contrast, <a href="https://core.ac.uk/download/pdf/33020495.pdf">have a compressed abdomen</a>, tucked away under a flattened but widened thorax and shell. This allows them to scuttle into rock crevices for protection. Evolution repeatedly hit upon this solution because it works well under similar sets of circumstances. </p>
<h2>Five groups of “crabs”</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498499/original/file-20221201-16-bl39eg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">King crabs evolved from lobster-like ancestors within the Anomura.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=35474722">By CSIRO, CC BY 3.0</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498554/original/file-20221201-14988-9jfith.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Redeye sponge crabs carry sponges with them for camouflage.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/redeye-sponge-crabs-found-flower-garden-1810200487">Porco_Rosso/Shutterstock</a></span>
</figcaption>
</figure>
<p>The largest crab group are the <a href="https://www.gbif.org/species/11132538">Brachyura</a> (true crabs) including the edible crab and Atlantic blue crab. They had an ancestor that was also crab shaped. Some species have evolved “backwards” and straightened out their abdomens again. The other large group are the Anomura (false crabs), with an ancestor that looked more like a lobster.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498555/original/file-20221201-26-vp6qkz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Porcelain crabs superficially resemble true crabs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sea-anemone-clownfish-1285037704">volkan yenel/Shutterstock</a></span>
</figcaption>
</figure>
<p>However, at least four groups of Anomura – <a href="https://www.gbif.org/species/8038">sponge crabs</a>, <a href="https://www.gbif.org/species/8673">porcelain crabs</a>, <a href="https://www.gbif.org/species/8146">king crabs</a> and the Australian <a href="https://www.gbif.org/species/4312470">hairy stone crab</a> – have independently evolved into a crab-like form in much the same way as the true crabs. Like the true crabs, their compact bodies are more defensive, and can move sideways faster. </p>
<p>This means “crabs” aren’t a real biological group. They are a collection of branches in the decapod tree that evolved to look the same. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498685/original/file-20221202-18-8fv4d1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hairy stone crab (Lomis hirta)</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Hairy_Stone_Crab_(Lomis_hirta)_(49782727391).jpg">Tim Binns/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But crabs aren’t the exception. </p>
<p>Something similar happened in the evolution of birds from feathered dinosaurs. Feathers may have first evolved for insulation, to attract mates, for protecting eggs and possibly also as “nets” for <a href="https://www.theguardian.com/science/2015/nov/05/dakotaraptor-feathered-winged-carnivore-south-dakota">catching prey</a>. Millions of years later, feathers elongated and streamlined for flying. </p>
<p>Palaeontologists disagree about the details, but all modern birds (Neoaves) evolved from <a href="https://www.bath.ac.uk/announcements/modern-tree-dwelling-birds-evolved-from-the-ground-up/">ground-dwelling ancestors</a> just after the mass extinction that wiped out the other dinosaurs. However, feathered wings and flight also evolved earlier in other groups of dinosaurs, including <a href="https://www.biorxiv.org/content/10.1101/2020.04.17.046169v1">troodontids and dromaeosaurs</a>. Some of these, like <em>Microraptor</em>, had four wings. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498500/original/file-20221201-6380-uqkut1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Microraptors had two pairs of wings.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Re-running the tape of life</h2>
<p>Unfortunately we can’t run evolutionary experiments to see if the same things keep happening because that would take hundreds of millions of years. But the history of life has already done something similar to that for us, when closely related lineages evolve and diversify on different continents. In many cases, these ancestral lines repeatedly came up with the same or almost identical solutions to problems.</p>
<p>One of the best examples is our own group, the mammals.</p>
<p>There are two major groups of living mammals. The placentals (including us) and the marsupials (pouched mammals who give birth to tiny young). Both groups evolved from the same common ancestor over <a href="https://www.nature.com/articles/nature10291">100 million years ago</a>, the marsupials largely in Australasia and the Americas and the placentals elsewhere. </p>
<p>This isolation led to two almost independent runs of the “experiment” to see what could be done with the mammal bodyplan. There are marsupial and placental versions of moles, mice, anteaters, gliders, and cats. There was even a marsupial wolf (the thylacine, <a href="https://www.bbc.co.uk/news/world-australia-63855426">extinct in 1936</a>), whose skull and teeth match those of the placental wolf in astonishing detail.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=169&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=169&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=169&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=212&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=212&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498533/original/file-20221201-26-5ca973.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=212&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Skulls of the marsupial thylacine (left) and placental wolf (right) show striking convergence, despite evolving apart on different continents.</span>
</figcaption>
</figure>
<p>It’s not only body forms that evolve independently, but also organs and other structures. Humans have <a href="https://www.nei.nih.gov/learn-about-eye-health/healthy-vision/how-eyes-work">complex camera eyes</a> with a lens, iris and retina. Squid, and octopuses, which are molluscs and more closely related to snails and clams, also evolved camera eyes with the same components. </p>
<p>Eyes more generally may have evolved independently up to <a href="https://www.nature.com/articles/eye2017226">40 times</a> in different groups of animals. Even box jellyfish, which don’t have a brain, have eyes with lenses at the bases of their four tentacles. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=282&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=282&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=282&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=355&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=355&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498526/original/file-20221201-26-d659o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=355&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The eyes of the box jellyfish. These invertebrates from near the base of the animal tree of evolution have complex eyes.</span>
</figcaption>
</figure>
<p>The more we look, the more we find. Structures such as jaws, teeth, ears, fins, legs and wings all keep evolving independently across the animal tree of life.</p>
<p>More recently, scientists discovered convergence also happens at the molecular level. The opsin molecules in eyes that convert photons of light into chemical energy and enable humans to see have a <a href="https://www.frontiersin.org/articles/10.3389/fnana.2022.916510/full">tight resemblance to those in box jellyfish</a>, and evolved that way in parallel. Even more bizarrely, animals as different as whales and bats have striking convergence in the genes that <a href="https://www.nature.com/scitable/blog/accumulating-glitches/an_example_of_convergent_evolution/">enable them to echolocate</a>.</p>
<h2>Are humans really unique?</h2>
<p>Many of the things we like to think make humans special have been reinvented by evolution elsewhere. Corvids like crows and ravens have problem-solving intelligence and, along with owls, <a href="https://core.ac.uk/download/pdf/82734804.pdf">can use simple tools</a>. </p>
<p>Whales and dolphins <a href="https://www.nhm.ac.uk/discover/social-lives-of-whales.html">have complex social structures</a>, and their big brains allowed them to develop language. Dolphins use tools like sponges to <a href="https://ocean.si.edu/ocean-life/marine-mammals/sponge-wielding-bottlenose-dolphin">cover their noses</a> while they forage across stony sea bottoms. Octopuses also use tools and <a href="https://courses.washington.edu/anmind/Observational%20learning%20in%20O.%20vulgaris.pdf">learn from watching</a> what happens to other octopuses. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498502/original/file-20221201-6403-b45kge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Octopus marginatus hiding between two shells from East Timor.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Octopus_shell.jpg">Nick Hobgood</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>If things keep evolving in similar ways here on Earth, there’s a possibility they might also follow a related course if life has evolved elsewhere in the universe. It might mean <a href="https://theconversation.com/what-do-aliens-look-like-the-clue-is-in-evolution-63899">extra-terrestrial beings look less alien</a> and more familiar than we expect.</p><img src="https://counter.theconversation.com/content/195739/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Wills receives funding from BBSRC, NERC, The Leverhulme Trust and The John Templeton Foundation</span></em></p>In different parts of the world evolution often comes up with the same or similar solutions to life’s problems.Matthew Wills, Professor of Evolutionary Palaeobiology at the Milner Centre for Evolution, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1933022022-10-31T01:15:18Z2022-10-31T01:15:18Z7 ‘creepy crawlies’ you don’t need to be afraid of this spooky season<figure><img src="https://images.theconversation.com/files/492455/original/file-20221031-18-y3ad6b.jpeg?ixlib=rb-1.1.0&rect=20%2C14%2C1911%2C1931&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/54516708">vinitapuniasangwan/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>The <a href="https://australian.museum/learn/teachers/learning/bugwise/invertebrate-biodiversity/">vast majority</a> of animals on Earth are invertebrates (animals without backbones) – such as insects, arachnids and crustaceans.</p>
<p>These amazing animals are absolutely <a href="https://www.caledonianconservation.co.uk/cms/resources/Publications/cieemip68jun2010cathrine.pdf">crucial to our ecosystems</a>: they are pollinators, pest controllers, soil creators and waste managers. Invertebrates also serve as food for countless other animals. Despite all their hard work, many of these creatures are often described as “creepy crawlies”.</p>
<p>Their <a href="https://www.sciencealert.com/this-incredible-photo-of-an-ants-face-is-like-something-out-of-a-nightmare">alien-looking</a> bodies might seem like the stuff of nightmares, but the vast majority of invertebrate species are harmless to humans. In fact, the scariest thing about invertebrates is the rate at which they are <a href="https://www.nature.com/articles/s41467-018-07916-1">quietly disappearing</a> from our planet. </p>
<p>Here are seven fascinating creepy crawlies you don’t need to be afraid of.</p>
<h2>Social huntsman spiders (<em>Delena cancerides</em>)</h2>
<p>Native to Australia, social huntsman spiders live in <a href="https://web.archive.org/web/20131103103011/http://domingo.zoology.ubc.ca/avileslab/reprints/InsSoc95.Delena.pdf">large family groups</a> beneath the loose bark of dead or dying trees.</p>
<figure class="align-center ">
<img alt="Brown, large spiders blending into a wooden background" src="https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492423/original/file-20221030-38660-ga5tr8.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A colony of social huntsman spiders found under bark.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/48302773">meggsyroo/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Sound like nightmare fuel? Don’t worry, social huntsman spiders are gentle giants who rarely bite humans (and cause minimal harm when they do).</p>
<p>Unlike most spider species, social huntsmans live together in groups containing a large adult female and up to 300 of her offspring. Spiders will aggressively defend their nest <a href="https://link.springer.com/article/10.1007/s00040-009-0015-3">against outsiders</a>, suggesting they have ways of recognising nestmates from non-nestmates.</p>
<figure class="align-center ">
<img alt="A large, slightly translucent brown spider standing on a person's palm" src="https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492034/original/file-20221027-19202-e6cmuz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The social huntsman spider is large and entirely innocuous.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/37289318">mitchvandyke/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>At night, individual huntsmans leave the communal nest to hunt their insect prey. Although they are solitary hunters, spiders that come across the same insect will <a href="https://www.jstor.org/stable/41317219">share food</a> rather than fight with one another. In fact, spiderlings would rather <a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.2006.00223.x?casa_token=cN2B1dsuWVsAAAAA:k1GM9iOITclvEOxXa8KnaP1dejBiFzx05PkpFroAdwC5oiYgYQy674ZKbrhtiZRVpsfAU5AD_-ZQrzsC">starve to death than</a> cannibalise a fellow spider. By consuming large numbers of bugs, social huntsmans help to keep insect populations under control. </p>
<h2>Giant burrowing cockroach (<em>Macropanesthia rhinoceros</em>)</h2>
<p>Cockroaches are among the world’s most <a href="https://www.bbc.com/future/article/20140918-the-reality-about-roaches">feared and reviled</a> insects – which is a great pity, as most cockroaches are harmless animals that play <a href="https://www.abc.net.au/news/science/2021-04-18/cockroaches-insects-reasons-love-them-environment/100053056">a crucial role in our natural environment</a>. Take the giant burrowing cockroach, found in the warm <a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/f27d18f2-2e8c-4a29-bbaf-15d06c3f2bed">tropical and subtropical forests of Australia</a>.</p>
<figure class="align-center ">
<img alt="A very large dark brown carapaced beetle that spans the entire width of a human hand" src="https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492035/original/file-20221027-20183-52ozfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This burrowing cockroach is giant indeed.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/67279797">jessat/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>This gentle giant is the world’s heaviest species of cockroach, <a href="https://blog.csiro.au/insect-of-the-week-cockroach/">tipping the scales at 30-35 grams</a>. Unlike its infamous relatives, the giant burrowing cockroach is not a pest and prefers to spend most of its time in underground burrows. Giant burrowing cockroaches feed on dry eucalyptus leaves, which they collect and drag into their burrows.</p>
<p>By moving and mixing the soil, giant burrowing cockroaches help keep soils healthy. They are excellent mothers who feed and care for their young for <a href="https://academic.oup.com/aesa/article-abstract/84/6/575/96586?redirectedFrom=fulltext">up to nine months</a> after birth. The giant burrowing cockroach is also surprisingly long-lived, with a lifespan of <a href="https://www.bushheritage.org.au/species/giant-cockroaches">up to 10 years</a>.</p>
<h2>Baphomet moth (<em>Creatonotos gangis</em>)</h2>
<p>With weirdly pulsating tentacles, the Baphomet moth looks like an alien nightmare – but these moths are simply looking for love. When male Baphomet moths sense the presence of a female, they inflate enormous, <a href="https://www.australiangeographic.com.au/blogs/creatura-blog/2017/11/the-creatonotos-gangis-is-one-of-australias-strangest-insects/">tentacle-like organs called “coremata”</a>, which produce an irresistible female-attracting chemical bouquet.</p>
<figure class="align-center ">
<img alt="A grey moth with a red body, and four large, hairy tentacles extending from its lower abdomen" src="https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=627&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=627&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=627&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=787&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=787&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492036/original/file-20221027-20344-3hae63.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=787&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The internet has affectionately dubbed this bug ‘tentacle moth’, for obvious reasons.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/54516708">vinitapuniasangwan/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>While it’s not the only moth species with coremata, Baphomet moths take theirs to ridiculous lengths, with “tentacles” sometimes exceeding the length of their abdomens.</p>
<figure class="align-center ">
<img alt="A grey moth with dark stripes on wings sitting on a red dahlia flower" src="https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492037/original/file-20221027-18054-68il0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Baphomet moth doesn’t always have creepy tentacles.</span>
<span class="attribution"><span class="source">Bhupinder Bagga/Shutterstock</span></span>
</figcaption>
</figure>
<p>As caterpillars, male Baphomet moths get the ingredients they need to make their female-attracting scents by eating plant leaves that contain chemicals called <a href="https://en.wikipedia.org/wiki/Pyrrolizidine_alkaloid">pyrrolizidine alkaloids</a>. Plants produce these alkaloids to deter plant-munching animals, but Baphomet moths have evolved a way to <a href="https://fzi.uni-freiburg.de/pdf/1985_Boppre_Schneider.pdf">convert these chemicals</a> into their own attractive scents.</p>
<h2>Black soldier fly maggots (<em>Hermetia illucens</em>)</h2>
<p>A big, writhing mass of maggots might not sound like one of nature’s marvels, but the larvae of the black solder fly are recycling superheroes that may one day help <a href="https://www.canberratimes.com.au/story/7868087/tiny-fly-larvaes-big-food-waste-potential/">humanity cut down on food waste</a>. Roiling masses of soldier fly maggots can rapidly devour food through a process physicists colourfully described as a “<a href="https://www.livescience.com/64691-maggot-fountains.html">maggot fountain</a>”.</p>
<figure class="align-center ">
<img alt="A large pile of wriggly maggots of various shades of brown and beige" src="https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492422/original/file-20221030-68119-jkbdp7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The larvae of the black soldier fly are the quintessential ‘maggot’.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/71319102">eduardo4bv/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The incredible speed at which maggots demolish food waste has captured the attention of scientists who hope to use soldier fly maggots to convert waste products such as animal faeces and food waste into maggot-based proteins that can be fed to livestock or <a href="https://www.sciencedaily.com/releases/2020/10/201029104951.htm">humans</a>. Yum!</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/jWEM6ohctwU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Tailless whip scorpion (Amblypygi)</h2>
<p>Despite their name, tailless whip scorpions are not scorpions, but instead belong to an unusual group of arachnids called <a href="https://blogs.cornell.edu/rayor/amblypygids/">amblypygids</a>. Despite their fearsome appearance, amblypygids lack venom and are timid animals that rarely bite unless threatened.</p>
<figure class="align-center ">
<img alt="A large spider-like creature on a sandy wall with two eggs nearby" src="https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&rect=3%2C27%2C2041%2C1250&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492051/original/file-20221027-23859-k1fiu3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Charon grayi, a type of amblypygid, is a shy, retiring creature.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/73918617">teacherharvey/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>These shy animals prefer to stay hidden in humid habitats such as in leaf litter, inside caves or under bark.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1419903965035044866"}"></div></p>
<p>Amblypygids have elongated front legs that act as feelers and help the arachnid locate its insect prey. Once prey is detected, amblypygids use their sharp pedipalps to impale their victim.</p>
<p>Some of these arachnids display <a href="https://www.researchgate.net/profile/Linda-Rayor/publication/293760646_Family_ties/links/60453ee6a6fdcc9c781dc908/Family-ties.pdf">complex social behaviours</a>, with mothers staying near and caring for their young for up to a year. </p>
<h2>The giant elephant mosquito (<em>Toxorhynchites speciosus</em>)</h2>
<p>Few things in life are as horrifying as the high-pitched squeal of a mosquito in the dark. Now imagine an enormous mosquito five times the size of your average mozzie. Measuring in at a shocking <a href="https://www.qm.qld.gov.au/Explore/Find+out+about/Ask+an+Expert/Question+of+the+month/Question+Archive/Questions/2021/January+2021">8mm in length</a>, the Australian elephant mosquito is the world’s largest mosquito species.</p>
<figure class="align-center ">
<img alt="Close-up of a shiny mosquito with feathered antennae" src="https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=443&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=443&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=443&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492053/original/file-20221027-25221-lf1bpj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Thankfully, the world’s largest mosquito doesn’t lust after human blood.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/18770512">steve_kerr/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>But fear not, this enormous mozzie is a <a href="https://www.qm.qld.gov.au/Explore/Find+out+about/Ask+an+Expert/Question+of+the+month/Question+Archive/Questions/2021/January+2021">nectar-sipping vegetarian</a>.</p>
<p>Most female mosquitoes need a meal of blood to provide nutrients for their developing eggs. Female elephant mosquitoes collect much-needed nutrients by feeding voraciously on other aquatic insects when they are larvae. And it gets better, because the favourite food of larval elephant mosquitoes is … <a href="https://www.youtube.com/watch?v=tYOMbTizqKA">other mosquito larvae</a>!</p>
<h2>Common scorpion fly (<em>Panorpa</em>)</h2>
<p>Scorpionflies look like a bizarre mashup between a fly and a scorpion. Combine their sinister appearance with a somewhat ghoulish habit of feeding on <a href="https://academic.oup.com/jme/article/52/2/143/887211?login=false">fresh human corpses</a>, and you have the makings of an excellent horror movie.</p>
<p>Luckily, scorpionflies are not, as their name suggests, flying scorpions, nor are they capable of harming a human. In fact, scorpionfly “stingers” are actually enlarged male genitalia!</p>
<figure class="align-center ">
<img alt="A large fly with mottled wings that appears to have a scorpion's tail" src="https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492055/original/file-20221027-19729-pkqydq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The male scorpionfly has claspers at the end of its tail that look like a scorpion’s tail.</span>
<span class="attribution"><span class="source">CHEN HSI FU/Shutterstock</span></span>
</figcaption>
</figure>
<p>During courtship, male scorpionflies attempt to woo females by offering them either a dead insect or <a href="https://onlinelibrary-wiley-com.ezproxy.library.sydney.edu.au/doi/full/10.1111/j.1463-6395.2010.00474.x?casa_token=_6NoEI7Is3YAAAAA%3AOCP0g5_qtAauQBgfTo0wxxhMAwiTczPXIDoghrG73mbL1PuHHZkzpIUk8uIFpwaXsUjpA1XRp4J2AdtC">a blob of saliva</a>. Scorpion flies are mostly scavengers and are frequently seen stealing prey from spider webs.</p>
<p>They are among the first insects to turn up on newly deceased corpses, making them important for <a href="https://academic.oup.com/jme/article/52/2/143/887211?login=false">establishing time of death</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-remains-are-found-in-a-suitcase-forensics-can-learn-a-lot-from-the-insects-trapped-within-189315">When remains are found in a suitcase, forensics can learn a lot from the insects trapped within</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/193302/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tanya Latty receives funding from The Australian Research Council. She is affiliated with Invertebrates Australia (conservation organisation), the Australasian Society for the Study of Animal Behaviour and the Australian Entomological Society </span></em></p>Invertebrates are the most abundant animals on our planet – and the vast majority are nothing to be afraid of, despite their appearances.Tanya Latty, Associate professor, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1931442022-10-28T09:29:12Z2022-10-28T09:29:12ZDead crustaceans washing up on England’s north-east coast may be victims of industrial revival<figure><img src="https://images.theconversation.com/files/491856/original/file-20221026-21-aorh0d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Thousands of dead and dying crustaceans were found along Teesside's coastlines last year.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pile-dead-crabs-high-quality-photo-2177645265">FlorianKunde/Shutterstock</a></span></figcaption></figure><p>Thousands of dead and dying crabs and lobsters <a href="https://www.theguardian.com/environment/2022/sep/03/we-just-want-the-truth-british-coastal-towns-fight-for-answers-over-mystery-sealife-deaths">washed up</a> along a 50km stretch of England’s north-east coast last autumn. Observers reported seeing the animals experience peculiar behaviours including convulsions, before suffering paralysis and death.</p>
<p>An <a href="https://www.gov.uk/government/publications/joint-agency-investigation-into-teesside-and-yorkshire-coast-crab-and-lobster-mortalities">initial investigation</a> conducted by the Department of Environment, Food & Rural Affairs, concluded that a harmful algal bloom was most likely responsible for the deaths. Autumnal phytoplankton blooms are a normal part of temperate marine ecosystems and can produce potent toxins that attack an animal’s central nervous system. But such blooms typically don’t lead to deaths on the scale seen.</p>
<p>The government’s explanation has been <a href="https://www.whitbylobsterhatchery.co.uk/storage/pdf/NEFC-MASS-MORTALITY-REPORT-TDJ-(MARCH-2022).pdf">contested</a> by local fishermen. They believe recent intensive dredging has released industrial toxins, including pyridine, from the sediment of the River Tees. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An aerial shot of an industrial area on the river tees, with a blue bridge in the foreground." src="https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/491718/original/file-20221025-15224-fm2yzw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The legacy of Teesside’s industrial past can be seen today.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/teesside-middlesbrough-transporter-bridge-showing-river-1220827276">Nigel Rusby/Shutterstock</a></span>
</figcaption>
</figure>
<p>As an industrial solvent, pyridine is used in a wide range of manufacturing processes. It is also a by-product of <a href="https://www.sciencedirect.com/topics/engineering/coking-coal">coking coal</a>, a crucial input for steel production. The Tees area was home to both steel and chemical industries and the discharge of <a href="http://www.environmentdata.org/archive/ealit:1385/OBJ/19001163.pdf">contaminated effluent</a> into the river and surrounding wetlands has been common practice, often with minimal or no treatment. </p>
<p>Attempts to understand what caused these deaths has set traditional coastal industries on a collision course with the region’s green growth aspirations. </p>
<p>I took part in efforts to determine what actually happened and whether pyridine could have caused the death of these crabs and lobsters. Using standard ecotoxicology methods, <a href="https://www.ncl.ac.uk/press/articles/latest/2022/09/pyridinecrabs/">my research</a> involved monitoring the behaviour, physiology and survival of the crustaceans in carefully controlled pyridine solutions. It became clear to me that pyridine may have played a major role in the death of these animals.</p>
<h2>The redevelopment of Teesside</h2>
<p>As one of the UK’s industrial heartlands, Teesside has been designated as a special economic zone, or <a href="https://www.gov.uk/guidance/freeports#what-are-freeports">freeport</a>. The region will play a key role in the government’s <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1095544/Executive_Summary.pdf">Levelling Up</a> programme and <a href="https://www.gov.uk/government/publications/clean-growth-strategy/clean-growth-strategy-executive-summary">Clean Growth Strategy</a>, including hosting the UK’s first <a href="https://www.gov.uk/government/news/tees-valley-hydrogen-hub-boosted-by-20-million-competition">hydrogen transport hub</a>. </p>
<p>To facilitate this, the region’s major sea port is undergoing <a href="https://www.teesworks.co.uk/the-development/masterplan">redevelopment</a>. Teesport’s shipping canal has been widened and deepened and the South Bank quay is being reconstructed. This required dredging. Taking place last autumn, almost <a href="https://www.thenorthernecho.co.uk/news/20199323.teesside-freeport-dredging-likely-take-place-year/">150,000 tonnes of sediment</a> has been displaced from the Tees estuary as part of the project.</p>
<p>The onset of the marine deaths coincided with this dredging campaign. This prompted the Environment Agency to undertake chemical analysis of the dead crabs. Pyridine levels recorded in the dead crabs were <a href="https://www.gov.uk/government/news/update-on-investigation-into-the-deaths-of-crabs-and-lobster-in-the-north-east">substantially higher</a> than in those from outside the impacted area. But there was no existing toxicological data on the impact of pyridine on crabs and other large crustaceans. </p>
<p>My research concluded that pyridine is acutely toxic to crabs at concentrations well below those measured in the dead crabs. Even surviving crabs with very low pyridine doses behaved as if they were partially anaesthetised. A single droplet of pyridine per litre of seawater would be sufficient to kill half of the crab population exposed to it. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1575505208578568194"}"></div></p>
<p>Further analysis of biochemical markers showed major spikes in the production of <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/reactive-oxygen-species">reactive oxygen species</a> in the muscle tissue. This means that the animal’s muscle cells have experienced major stress, with the potential for damage to DNA, proteins and cell membranes, which could lead to cell death. </p>
<p>However, although pyridine was detected in the crabs examined by the government investigation, it was not detected in water samples. As a result, pyridine’s involvement in the deaths has been <a href="https://www.gov.uk/government/news/update-on-investigation-into-the-deaths-of-crabs-and-lobster-in-the-north-east">dismissed</a> by the Environment Agency.</p>
<h2>Why has pyridine gone undetected?</h2>
<p>Pyridine is highly water soluble, very volatile and vulnerable to attack and destruction by oxygen. By the time water samples are taken, any pyridine could have been heavily diluted, lost to the atmosphere or destroyed. </p>
<p>Despite this, earlier this year researchers at the University of York still <a href="https://drive.google.com/file/d/10mJtcqEsq_ozNFg83FipnkUY1XkPAlnU/view">measured</a> trace levels of pyridine in surface sediments both along the River Tees estuary and in the spoil grounds – the areas of the sea where dredged material is deposited. Given the volatility and instability of pyridine in the presence of oxygen, this implies a large pyridine reservoir deep in the sediment of the Tees that is percolating steadily up to the surface.</p>
<p><a href="https://www.ncl.ac.uk/nes/people/profile/miguelmorales-maqueda.html">My colleague</a> at Newcastle University has also undertaken a range of <a href="https://www.ncl.ac.uk/press/articles/latest/2022/09/pyridinecrabs/">computer simulations</a>. They show that this reservoir, once disturbed by dredging, could have released enough pyridine (among many other chemical contaminants) to account for mortalities on the scale and range of those recorded last autumn. The size of the pyridine reservoir still needs to be verified to ground the models in real-world data. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1575892995320303617"}"></div></p>
<p>Research has so far <a href="https://www.teesworks.co.uk/dredging?fbclid=IwAR0BKcT6dQ6_CPoQv524YYjCjWY_6jXJy9goHkNtaT3EVrCU4ce45jH2CtA#:%7E:text=On%201%20September%202022%2C%20Teesworks,well%20as%20future%20offshore%20developments">not prevented</a> additional dredging work for the new South Bank quay. But the sediment there <a href="https://www.darlingtonandstocktontimes.co.uk/news/20223245.tests-rule-dredged-material-near-new-tees-quay-must-not-disposed-sea/">contains high levels</a> of long-lasting pollutants, including heavy metals and various industrial chemicals. Should these sediments be dumped at sea, it could render England’s northeast coastline toxic for generations.</p>
<p>Teesside is undergoing rapid redevelopment to hasten the green industrial revolution. But in so doing we have been forced to reconcile with the region’s industrial legacy. By carrying out additional research we can better understand this issue and inform future action to prevent further damage to the marine ecosystem.</p>
<p><em>The headline of this article was amended to clarify that redevelopment to enable new industries, rather than green industrial processes themselves, is being blamed for the crustacean death.</em></p><img src="https://counter.theconversation.com/content/193144/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gary Caldwell receives funding from The Fishmongers' Company and Ofwat. He is affiliated with the Green Party. </span></em></p>A mass die-off of crustaceans occurred on England’s north-east coast last autumn – the government’s explanation of the cause is unlikely to be true.Gary Caldwell, Senior Lecturer in Applied Biology, Newcastle UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1833422022-07-04T05:13:54Z2022-07-04T05:13:54ZThousands of giant crabs amass off Australia’s coast. Scientists need your help to understand it<figure><img src="https://images.theconversation.com/files/472221/original/file-20220704-23-23puw1.jpg?ixlib=rb-1.1.0&rect=4%2C2%2C1491%2C992&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Julian Finn/Museums Victoria</span></span></figcaption></figure><p><em><strong><a href="https://theconversation.com/au/topics/am-i-not-pretty-enough-106740">Am I not pretty enough?</a></strong> This article is part of The Conversation’s series introducing you to little-known Australian animals that need our help.</em></p>
<hr>
<p>Every winter in shallow waters off Australia’s southern coast, armies of native spider crabs appear in their thousands. They form huge underwater piles, some as tall as a person. These fascinating crustaceans are on a risky mission – to get bigger.</p>
<p>Crabs cannot simply grow like humans and other soft-bodied creatures. They must break free from their shells, expand their soft flesh and harden a new shell – all while dodging hungry predators on the hunt for a soft, easy meal.</p>
<p>This moulting process leaves crabs clumsy and uncoordinated, making any escape tricky. That’s thought to be one reason they clump together in such big numbers – to keep each other safe.</p>
<p>The spectacular gatherings attract tourists from interstate and overseas and have even been featured in a BBC <a href="https://www.bbc.co.uk/programmes/b09gl670">documentary</a>. But despite all this attention, scientists know very little about these quirky creatures. We need your help to investigate.</p>
<figure class="align-center ">
<img alt="A spider crab on sand" src="https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472219/original/file-20220704-23-feojwu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">There’s still much to learn about spider crabs.</span>
<span class="attribution"><span class="source">Julian Finn/Museums Victoria</span></span>
</figcaption>
</figure>
<h2>Safety in numbers</h2>
<p>Southern Australia’s spider crabs (<em>Leptomithrax gaimardii</em>) are usually orange to red-brown. They can reach 16cm across their shell and 40cm across their legs, and are commonly known as great spider crabs.</p>
<p>Spider crabs are believed to be widely dispersed in deeper waters. But they’re most visible to humans when they congregate <a href="https://collections.museumsvictoria.com.au/species/14370">near shore in winter</a>, and occasionally at other times of year.</p>
<p>Once together, spider crabs shed their old shells in a synchronised act thought to take about <a href="https://collections.museumsvictoria.com.au/species/14370">an hour</a>. The crabs stay together until their new hard shells form, which probably takes a few days. </p>
<p>The aggregation can last a few weeks. Soft crabs are thought to take refuge in the middle of the piles, protected by crabs yet to moult.</p>
<p>Afterwards, spider crabs return to deeper waters and their solitary lives, leaving the seafloor littered with discarded shells. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-tiny-wasp-could-save-christmas-islands-spectacular-red-crabs-from-crazy-ants-69646">A tiny wasp could save Christmas Island's spectacular red crabs from crazy ants</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Freshly moulted spider crab next to its old shell" src="https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467455/original/file-20220607-24-25a144.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A freshly moulted spider crab, left, next to its old shell.</span>
<span class="attribution"><span class="source">Elodie Camprasse</span></span>
</figcaption>
</figure>
<h2>Plenty of mysteries to solve</h2>
<p>Spider crab aggregations have been officially reported along the Victorian and Tasmanian coasts. Historically, most winter sightings have been reported on the Mornington Peninsula – particularly near the Rye and Blairgowrie piers. </p>
<p>Anecdotal evidence suggests the gatherings can also happen elsewhere. For instance, an aggregation was reported this year on the western side of Port Phillip Bay.</p>
<p>But there’s still so much we don’t know about spider crabs, such as:</p>
<ul>
<li>how many spider crabs are out there?</li>
<li>how many gather en masse? </li>
<li>how long do the crabs stay?</li>
<li>what signals do crabs use to know it’s time to come together? </li>
<li>why do the crabs aggregate at one location in several consecutive years then not return? </li>
</ul>
<p>Most spider crab gatherings seem to occur in winter, but they’re known to come together at other times. For example, aggregations in late spring, midsummer and early autumn have been reported in parts of Port Phillip Bay and elsewhere Victoria and Tasmania.</p>
<p>Those aggregations don’t seem related to moulting – in fact, we have no idea why they occur! </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/nV5GjrlW6_Y?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Source: Elodie Camprasse.</span></figcaption>
</figure>
<h2>We need your help</h2>
<p>To better understand spider crab aggregations, a citizen science project called <a href="https://www.inaturalist.org/projects/spider-crab-watch">Spider Crab Watch</a> has been launched.</p>
<p>We’re inviting everyone – including divers, fishermen, swimmers and boaters – to report where they see spider crabs, alone or in groups. We’d also love to hear from people who come across discarded spider crab shells on the beach, because that indicates an aggregation occurred nearby. </p>
<p>The reports will help us determine the habitats and conditions suitable for spider crab aggregations. We welcome sightings from Port Phillip Bay and across the Great Southern Reef, where spider crabs live. The reef spans the southern part of Australia from New South Wales to Western Australia and Tasmania.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-counting-birds-to-speaking-out-how-citizen-science-leads-us-to-ask-crucial-questions-166673">From counting birds to speaking out: how citizen science leads us to ask crucial questions</a>
</strong>
</em>
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<hr>
<p>Logging a sighting is a quick process. Just report the date, time and location of the spider crabs, and answer a few questions. Photos are not essential but always welcome.</p>
<p>We’re also using traditional research to solve these mysteries. This includes underwater surveys, spider crab tagging and the use of timelapse cameras to capture images of spider crabs and their predators at sites where aggregations are expected.</p>
<p>After the aggregations, the images captured will be uploaded to a web portal. Interested people from around the country (and the world) can then analyse the images to help us count spider crabs and identify their predators.</p>
<p>If that interests you, <a href="https://redcap.link/ybjksj1z">sign up</a> for Spider Crab Watch updates.</p>
<p>This program and the broader research is supported by funding from the Victorian government.</p>
<figure class="align-center ">
<img alt="spider crab aggregation below divers" src="https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467449/original/file-20220607-12-d1p16o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scientists want people to report where they see spider crabs.</span>
<span class="attribution"><span class="source">Elodie Camprasse</span></span>
</figcaption>
</figure>
<h2>Understanding our oceans</h2>
<p>The aims of this research go far beyond spider crabs. Scientists also want to know if spider crab gatherings help predators maintain healthy populations. </p>
<p>Huge stingrays, seals, seabirds and some sharks are often spotted near aggregation sites. But we need more information to understand how crab aggregations affect animals at the top of the food chain.</p>
<p>Spider crabs have captured the imagination of ocean lovers for decades – yet we know so little about their lives.</p>
<p>This project will help us gather information on this amazing natural spectacle and the role it plays in the marine environment. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/octopus-crabs-and-lobsters-feel-pain-this-is-how-we-found-out-173822">Octopus, crabs and lobsters feel pain – this is how we found out</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/183342/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Elodie Camprasse receives funding from the Victorian government.</span></em></p>Spider crabs form huge underwater piles, some as tall as a person. These fascinating crustaceans are on a risky mission – to get bigger.Elodie Camprasse, Research fellow in spider crab ecology, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1738222021-12-16T14:01:43Z2021-12-16T14:01:43ZOctopus, crabs and lobsters feel pain – this is how we found out<figure><img src="https://images.theconversation.com/files/438317/original/file-20211219-25-1pc214a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/octopus-almost-red-pink-marbled-skin-1113663953">Daniel Eskridge/shutterstock</a></span></figcaption></figure><p>Does a lobster feel pain when you pop it in a pot? The UK government asked us to find out. </p>
<p>We were commissioned to find out the likelihood of sentience – the capacity to have feelings, such as pain and pleasure – in two groups of invertebrate animals: the cephalopod molluscs (including octopuses, cuttlefishes and squids) and decapod crustaceans (including lobsters, crabs and prawns). We found strong and diverse evidence of sentience in both. And <a href="https://www.lse.ac.uk/News/News-Assets/PDFs/2021/Sentience-in-Cephalopod-Molluscs-and-Decapod-Crustaceans-Final-Report-November-2021.pdf">our recent report</a>, which reviewed over 300 scientific studies, led to the <a href="https://www.gov.uk/government/news/lobsters-octopus-and-crabs-recognised-as-sentient-beings">UK government’s decision</a> to legally recognise all of these animals as sentient beings.</p>
<p>You may wonder how we find out if an animal can feel pain. It’s tempting to think we only need to look at whether they try to avoid or escape being injured. However, after touching a hot stove, humans withdraw their hand before feeling the burn. Hand withdrawal is an <a href="https://nba.uth.tmc.edu/neuroscience/m/s3/chapter02.html">unconscious reflex</a>. Perhaps other animals only respond reflexively to injury, without experiencing pain.</p>
<p>For our investigation, we used eight scientific criteria for determining sentience. </p>
<p>The first four addressed whether the animal’s nervous system could support sentience. We wanted to find out whether it can detect harmful stimuli and transmit those signals to the brain. And also whether the signals were processed in integrative brain regions - parts of the brain that bring together information from many sources. Finally, it was important to understand whether anaesthetic or painkillers changed the nervous system response.</p>
<p>Our four remaining criteria focused on the animal’s behaviour. Could they trade-off risks of injury against opportunities for a reward? Did individuals tend to the specific site of an injury, and could they learn to avoid stimuli associated with injury, for example? We also investigated whether they valued anaesthetics or painkillers when injured. This behaviour, which distinguishes rigid and reflex reactions to injury, such as withdrawing a burnt hand, from flexible responses, is taken to be evidence of pain.</p>
<p>Individually, none of our criteria proves that a creature is sentient. But the more criteria it meets, the more likely sentience becomes. </p>
<h2>Signs of feeling</h2>
<p>We found the strongest evidence for sentience in cephalopods. Octopuses were the stars. With around 170 million brain cells, they have <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-185X.1972.tb00975.x?casa_token=uAker4z4CR8AAAAA:a2U39Z1GVoaQ69BEQxJ0GZhvR-D6wMEp4HlM1FmVYPcZ9Bw2Undihf4Ho9dc5NS8J0z_bhTy6M_ZyN2S">higher brain-to-body ratios</a> than most reptiles and fish. This allows octopuses to perform remarkable feats of learning and memory.</p>
<p>Octopuses also behave in ways that point strongly to experiences of pain. For example, in a recent study, they were given <a href="https://www.sciencedirect.com/science/article/pii/S2589004221001978">three chambers to explore</a>. Injection with acetic acid in their initially preferred chamber led to octopuses avoiding that chamber from then on. Injured octopuses learned to prefer an alternative chamber, where local anaesthetic was available. This anaesthetic silenced nerve activity between the injury site and the brain. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4028681/">Similar findings in mammals</a> are taken to indicate the subjective experience of pain. </p>
<figure class="align-center ">
<img alt="Two crabs on a table with their claws taped up" src="https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437880/original/file-20211215-13-1y9noz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Crabs capacity to feel pain has implications for animal welfare.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/close-up-on-crabs-on-table-10432611/">RODNAE Productions/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Decapods also displayed compelling signs of sentience. For instance, one <a href="https://www.science.org/doi/abs/10.1126/science.1248811">high-profile study</a> allowed crayfish to explore a cross-shaped tank. Two arms of the cross were illuminated, whereas the other two were shaded. In the wild, crayfish use dark shelters to hide from predators, so time spent in the shaded arms was taken to measure anxiety-like behaviour. Exposure to an electric field caused crayfish to avoid the light arms. Administering an anti-anxiety drug reversed the effect. These findings reveal that crayfish have mental states with similar brain mechanisms and behaviour to anxiety.</p>
<p>Despite striking evidence for sentience in some well-studied species, there are 750 cephalopod species and 15,000 decapod species – more than double the total number of mammal species. Most individual species have never been studied in detail.</p>
<p>But sentience has never been studied in most individual vertebrate species either. With vertebrates, it is usually accepted that we can make reasonable generalisations from laboratory species – such as rats and zebrafish – to other species.</p>
<p>Invertebrates should be treated in the same way as vertebrates. That means protecting under-studied animals if it is reasonable to generalise from strong evidence in a better-studied species. This principle led us to recommend extending protection to all cephalopod molluscs and all decapod crustaceans.</p>
<h2>Implications for welfare</h2>
<p>Recognising these animals as sentient is undoubtedly a step forward for <a href="https://www.legislation.gov.uk/ukpga/2006/45/contents">UK animal welfare law</a>, which currently applies almost exclusively to vertebrates. Some other countries, such as New Zealand, Norway and Sweden, have already given <a href="https://api.worldanimalprotection.org/">invertebrates legal protection</a>. These cover issues such as the storage and slaughter of decapods in the food industry.</p>
<p>But in the UK, current industry practices will not be affected as the new bill does not apply to existing law. That means that procedures like boiling lobsters, asphyxiating octopuses and dismembering crabs will still continue.</p>
<p>We hope our report begins a wider conversation about how these animals can be treated humanely so we can minimise their pain and suffering. Many techniques, such as electrical stunning and rapid slaughter, are already informally considered best practice. Encouraging and enforcing best practice could <a href="https://link.springer.com/chapter/10.1007%2F978-3-030-11330-8_2">protect producers</a> against the erosion of standards, and reassure consumers that their expectations of high welfare standards are being met.</p><img src="https://counter.theconversation.com/content/173822/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Crump receives funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme, Grant Number 851145. He is affiliated with the Animal Welfare Research Network, Association for the Study of Animal Behaviour, and Universities Federation for Animal Welfare.</span></em></p><p class="fine-print"><em><span>Jonathan Birch receives funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme, Grant Number 851145.</span></em></p><p class="fine-print"><em><span>Alexandra Schnell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Octopus, crabs, prawns demonstrate clear signs of emotion, such as pain and ‘anxiety-like’ behaviour.Alexandra Schnell, Research Fellow in Comparative Psychology, Darwin College, University of CambridgeAndrew Crump, Postdoctoral Research Officer, London School of Economics and Political ScienceJonathan Birch, Associate Professor of Philosophy, London School of Economics and Political ScienceLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1612142021-06-01T11:28:50Z2021-06-01T11:28:50ZHow we discovered a giant new crustacean scavenging on the deepest depths of the ocean floor<figure><img src="https://images.theconversation.com/files/401617/original/file-20210519-13-168up36.JPG?ixlib=rb-1.1.0&rect=121%2C675%2C4039%2C2032&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Eurythenes atacamensis_, a giant scavenging amphipod from hadal depths of the Peru-Chile Trench.</span> <span class="attribution"><a class="source" href="https://doi.org/10.1007/s12526-021-01182-z">Alan Jamieson</a>, <span class="license">Author provided</span></span></figcaption></figure><p>Discovering a new species and placing it on the tree of life is a big responsibility. I have been fortunate to name four species from some of the <a href="https://doi.org/10.11646/zootaxa.4748.1.9">deepest</a>, most remote and <a href="https://doi.org/10.1080/14772000.2020.1729891">least sampled</a> parts of the ocean. Each new species helps us uncover how life thrives in the <a href="https://books.google.co.uk/books?hl=en&lr=&id=hqsPBgAAQBAJ&oi=fnd&pg=PR1&dq=jamieson+hadal+zone&ots=mwSGRXURPG&sig=UknVAyND0muPevPRqfvTtWB3BQs#v=onepage&q=jamieson%20hadal%20zone&f=false">hadal zone</a> (anywhere deeper than 6,000 metres or 3.7 miles). Now, let me introduce you to <a href="https://doi.org/10.1007/s12526-021-01182-z"><em>Eurythenes atacamensis</em></a>.</p>
<p><em>Eurythenes atacamensis</em> is an amphipod, a type of crustacean closely related to a shrimp, endemic to the <a href="https://www.britannica.com/place/Peru-Chile-Trench">Peru-Chile Trench</a> (also known as the Atacama Trench). Measuring more than 8cm in length, it is nearly twice the size of its nearest relative, making it a giant. Spanning an extensive vertical range, juveniles and adults can be found in the trench between 4,974 to 8,081 metres. This includes the deepest point, known as Richard’s Deep. </p>
<p>It is one of the most abundant members of the trench community, joining a <a href="https://theconversation.com/snailfish-how-we-found-a-new-species-in-one-of-the-oceans-deepest-places-103003">trio of snailfish</a> and long-legged, spider-like <a href="https://www.youtube.com/watch?v=txSOP_9yLCI">isopods</a>. As a <a href="https://doi.org/10.4319/lo.2007.52.4.1685">scavenger</a>, this amphipod plays a critical role within the food web by intercepting and redistributing food sinking down from above. They quickly detect and consume new carrion, like the mackerel bait we used to coax individuals into the trap. Unfortunately, they can accidentally ingest <a href="https://doi.org/10.1098/rsos.180667">microplastics</a> too.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/bFqluXB9HcE?wmode=transparent&start=10" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Timelapse of <em>Eurythenes atacamensis</em> feasting on the baited scientific lander at 6,980 metres deep in the Atacama Trench.</span></figcaption>
</figure>
<p>Their home is one of <a href="https://doi.org/10.1016/j.pocean.2018.01.007">35 trenches</a> that reach hadal depths. These trenches are formed by a geologic process called subduction (where one tectonic plate is forced under another causing the ocean floor to quickly plunge). The volume of the Atacama Trench is almost the same as the neighbouring Andes mountain range, also created by the tectonic subduction zone. </p>
<figure class="align-right ">
<img alt="Colour map of Atacama Trench." src="https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1184&fit=crop&dpr=1 600w, https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1184&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1184&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/402227/original/file-20210523-17-1agzf2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Atacama Trench in dark blue running along the spine of Peru to Chile.</span>
<span class="attribution"><span class="source">NOAA/Wikipedia</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Compared to the conditions at the surface, the <a href="https://doi.org/10.1016/j.tree.2009.09.009">hadal (or deep-sea) environment</a> seems extreme. It is pitch black with water temperatures varying between 1°C and 4°C at the deepest points. The hydrostatic pressure at hadal depths ranges from 600 to 1,100 atmospheres – equivalent to placing one-tonne on the end of your finger.</p>
<p>But this environment is entirely normal to the organisms that live there. Hadal inhabitants have a suite of biochemical, morphological and behavioural <a href="http://digital.ecomagazine.com/publication/?i=562381&article_id=3286789&view=articleBrowser&ver=html5">adaptions</a> that allow them to thrive in the trenches. Studying these ecosystems is not an easy task – which is why the hadal zone has been understudied compared to shallower parts of the ocean. </p>
<p>In 2018 two international research expeditions focused on the southern portion of the Atacama Trench. Scientists first set off on the Chilean vessel, RV Cabo de Hornos, to study the deepest part of the trench, Richard’s Deep, as part of the <a href="https://en.imo-chile.cl/post/2018-02-10-un-viaje-a-nuestro-mar-inescrutable-la-fosa-de-atacama.html">Atacamex expedition</a>. A month later, scientists on the German vessel, RV Sonne, <a href="https://epic.awi.de/id/eprint/49388/1/BzPM_0729_2019.pdf">studied</a> the wider trench ecosystem, sampling from 2,500 metres to Richard’s Deep.</p>
<p>During the expeditions, unmanned submersibles called <a href="https://www.sdu.dk/en/forskning/hadal/research/lander+work">landers</a> were deployed. Landers were equipped with robust deep-sea imaging equipment and baited traps to bring animals up for closer inspection. Both expeditions were a success and collected hundreds of hours of footage and thousands of amphipods – including <em>Eurythenes atacamensis</em> – as well as a <a href="https://theconversation.com/snailfish-how-we-found-a-new-species-in-one-of-the-oceans-deepest-places-103003">new species of snailfish</a>, affectionately nicknamed the “Little Purple Lovely” until its official scientific name is decided. </p>
<figure class="align-center ">
<img alt="A drawing of an deep-sea creature." src="https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=297&fit=crop&dpr=1 600w, https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=297&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=297&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=374&fit=crop&dpr=1 754w, https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=374&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/402228/original/file-20210523-13-1hlljwb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=374&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scientific illustration of the <em>Eurythenes atacamensis</em> holotype, a female from 8052 metres in the Atacama Trench.</span>
<span class="attribution"><span class="source">Johanna Weston/Marine Biodiversity</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Once the specimens were back on land, the detailed work to sort, measure, identify and describe new species commenced. <em>Eurythenes atacamensis</em> is a member of a well-studied deep-sea genus (<em>Eurythenes</em>), which is notorious for what is known as <a href="https://doi.org/10.11646/zootaxa.3971.1.1">cryptic speciation</a>. In other words, when it is hard to visually tell one species from another. The fantastic photographs of <em>Eurythenes atacamensis</em> were actually taken back in a <a href="https://doi.org/10.3354/meps10489">2009 expedition</a> to the trench. </p>
<p>At the time, it was first identified as <em>Eurythenes gryllus</em>. With the new 2018 specimens, we accounted for cryptic speciation by applying an <a href="https://doi.org/10.1186/1742-9994-7-16">integrative taxonomy approach</a> – pairing traditional morphology (the detailed study of an organism’s shape) with <a href="https://theconversation.com/dna-barcoding-a-better-way-to-discover-species-4933">DNA barcoding</a>. This latest research showed it was actually a different and undescribed species. </p>
<p>This taxonomic process helped us categorise organisms so we could more easily communicate the biological information. Together, the detailed visual assessment and genetics gave us a clear result that <em>Eurythenes atacamensis</em> was a new species. Once confident in the data, we selected several individuals to be described and illustrated. These individuals are called type specimens – the most important of which is the <a href="https://ecologyforthemasses.com/2019/09/12/preserving-biological-heritage-the-importance-of-type-specimens/">holotype</a> or the “name-bearing” specimen. We chose the name <em>atacamensis</em> in tribute to its home.</p>
<p>This discovery is another piece in the puzzle of understanding the world that we live in and the subtle interactions between organisms and their environment. It helps us understand how life thrives in the deepest parts of the ocean, under conditions that seem impossible to terrestrial mammals like us. It also gives us a glimpse into the hadal zone – not an extreme habitat bereft of life, but one filled with extraordinary biodiversity.</p><img src="https://counter.theconversation.com/content/161214/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The RV Sonne SO261 Expedition was funded by the HADES–ERC Advanced Grant “Benthic diagenesis and microbiology of hadal trenches” (Grant Agreement Number 669947) and the German Federal Ministry of Education and Research. The Atacamex Expedition was funded by the National Agency for Research and Development of Chile (ANID; Grant AUB 150006/12806). Additional support came from the Danish National Research Foundation, HADAL, (Grant number DNRF145), ANID through the Millennium Science Initiative Program (Grant ICN 12_019-IMO), and internal funding from Newcastle University</span></em></p>Deep ocean trenches are home to extraordinary biodiversity waiting to be discovered.Johanna Weston, PhD Marine Science candidate, School of Natural and Environmental Sciences, Newcastle UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1551372021-02-15T18:51:28Z2021-02-15T18:51:28ZBlind shrimps, translucent snails: the 11 mysterious new species we found in potential fracking sites<figure><img src="https://images.theconversation.com/files/383938/original/file-20210212-19-1y4jq3k.jpeg?ixlib=rb-1.1.0&rect=0%2C12%2C2087%2C1534&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An ostracod, a small crustacean with more than 70,000 identified species.</span> <span class="attribution"><span class="source">Anna33/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>There aren’t many parts of the world where you can discover a completely new assemblage of living creatures. But after sampling underground water in a remote, arid region of northern Australia, we discovered at least 11, and probably more, new species of stygofauna. </p>
<p>Stygofauna are invertebrates that have evolved exclusively in underground water. A life in complete darkness means these animals are often blind, beautifully translucent and often extremely localised – rarely living anywhere else but the patch they’re found in. </p>
<p>The species we discovered live in a region earmarked for fracking by the Northern Territory and federal government. As with any mining activity, it’s important future gas extraction doesn’t harm groundwater habitats or the water that sustains them.</p>
<p>Our findings, <a href="https://gisera.csiro.au/wp-content/uploads/2021/02/GISERA-Project18-Stygofauna_final-report-20201208.pdf">published today</a>, show the importance of conducting comprehensive environmental assessments before extraction projects begin. These assessments are especially critical in Australia’s north, where many plants and animals living in surface and groundwater have not yet been documented.</p>
<h2>When the going gets tough, go underground</h2>
<p>Stygofauna were first discovered in Western Australia in 1991. Since then, these underground, aquatic organisms have been recorded across the continent. Today, more than 400 Australian species have been formally recognised by scientists.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=840&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=840&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=840&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1055&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1055&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384203/original/file-20210215-23-d83h18.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1055&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The subterranean fauna we collected from NT aquifers, including a range of species unknown to science. A–C: Atyid shrimps, including <em>Parisia unguis</em>; D-F: Amphipods in Melitidae family; G: The syncarid species <em>Brevisomabathynella sp</em>.; H-J: members of the Candonidae family of ostracods; K: the harpacticoid species <em>Nitokra lacustris</em>; L: a new species of snail in the Caenogastropoda: M-N: Members of the Cyclopidae family of copepods; O: The worm species <em>Aeolosoma sp.</em></span>
<span class="attribution"><span class="source">GISERA</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Stygofauna are the ultimate climate change refugees. They would have inhabited surface water when inland Australia was much wetter. But as the continent started drying around 14 million years ago, they moved underground to the relatively stable environmental conditions of subterranean aquifers.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hidden-depths-why-groundwater-is-our-most-important-water-source-91484">Hidden depths: why groundwater is our most important water source</a>
</strong>
</em>
</p>
<hr>
<p>Today, stygofauna help maintain the integrity of groundwater food webs. They mostly graze on fungal and microbial films created by organic material leaching from the surface. </p>
<p>In 2018, the final report of an <a href="https://frackinginquiry.nt.gov.au/">independent inquiry</a> called for a critical knowledge gap regarding groundwater to be filled, to ensure fracking could be done safely in the Northern Territory. We wanted to determine where stygofauna and microbial assemblages occurred, and in what numbers. </p>
<p>Our project started in 2019, when we carried out a pilot survey of groundwater wells (bores) in the Beetaloo Sub-basin and Roper River region. The Beetaloo Sub-basin is potentially one of the most <a href="https://www.abc.net.au/news/2018-04-15/beetaloo-basin-at-the-heart-of-the-nt-fracking-gas-debate/9652390">important areas</a> for shale gas in Australia.</p>
<h2>What we found</h2>
<p>The stygofauna we found range in size from centimetres to millimetres and include: </p>
<ul>
<li><p>two new species of ostracod: small crustaceans enclosed within mussel-like shells </p></li>
<li><p>a new species of amphipod: this crustacean acts as a natural vacuum cleaner, feeding on decomposing material </p></li>
<li><p>multiple new species of copepods: tiny crustaceans which form a major component of the zooplankton in marine and freshwater systems </p></li>
<li><p>a new syncarid: another crustacean entirely restricted to groundwater habitats</p></li>
<li><p>a new snail and a new worm.</p></li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/383936/original/file-20210212-15-k8466y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A thriving stygofauna ecosystem lies beneath the surface of northern Australia’s arid outback. We sampled water through bores to measure their presence.</span>
<span class="attribution"><span class="source">Jenny Davis</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These species were living in groundwater 400 to 900 kilometres south of Darwin. We found them mostly in limestone karst habitats, which contain many channels and underground caverns.</p>
<p>Perhaps most exciting, we also found a relatively large, colourless, blind shrimp (<em>Parisia unguis</em>) previously known only from the Cutta Cutta caves near Katherine. This shrimp is an “apex” predator, feeding on other stygofauna — a rare find for these kinds of ecosystems. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=462&fit=crop&dpr=1 600w, https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=462&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=462&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=580&fit=crop&dpr=1 754w, https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=580&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/383934/original/file-20210212-23-zzbqy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=580&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A microscopic image of <em>Parisia unguis</em>, a freshwater shrimp.</span>
<span class="attribution"><span class="source">Stefanie Oberprieler</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Protecting groundwater and the animals that live there</h2>
<p>The Beetaloo Sub-basin in located beneath a major freshwater resource, the Cambrian Limestone Aquifer. It supplies water for domestic use, cattle stations and horticulture.</p>
<p>Surface water in this dry region is scarce, and it’s important natural gas development does not harm groundwater.</p>
<p>The stygofauna we found are not the first to potentially be affected by a resource project. Stygofauna have also been found at the <a href="https://theconversation.com/its-not-worth-wiping-out-a-species-for-the-yeelirrie-uranium-mine-116059">Yeelirrie uranium mine</a> in Western Australia, approved by the federal government in 2019. More research will be required to understand risks to the stygofauna we found at the NT site. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-not-worth-wiping-out-a-species-for-the-yeelirrie-uranium-mine-116059">It's not worth wiping out a species for the Yeelirrie uranium mine</a>
</strong>
</em>
</p>
<hr>
<p>The discovery of these new NT species has implications for all extractive industries affecting groundwater. It shows the importance of thorough assessment and monitoring before work begins, to ensure damage to groundwater and associated ecosystems is detected and mitigated.</p>
<figure class="align-center ">
<img alt="Gas infrastructure at Beetaloo Basin" src="https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=351&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=351&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=351&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=441&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=441&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384150/original/file-20210215-19-yinoa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=441&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Beetaloo Basin is part of the federal government’s gas expansion strategy.</span>
<span class="attribution"><span class="source">Department of Industry, Science, Energy and Resources</span></span>
</figcaption>
</figure>
<h2>Where to from here</h2>
<p>Groundwater is vital to inland Australia. Underground ecosystems must be protected – and not considered “out of sight, out of mind”.</p>
<p><a href="https://gisera.csiro.au/wp-content/uploads/2021/02/20-00341_GISERA_FACTSHEET_SGW-NTStygofauna_WEB_210210.pdf">Our study</a> provides the direction to reduce risks to stygofauna, ensuring their ecosystems and groundwater quality is maintained.</p>
<p>Comprehensive environmental surveys are needed to properly document the distribution of these underground assemblages. The new stygofauna we found must also be formally recognised as a new species in science, and their DNA sequence established to support monitoring programs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/383937/original/file-20210212-19-uxshb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=450&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Different species of copepods from various parts of the world.</span>
<span class="attribution"><span class="source">Andrei Savitsky/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Many new tools and approaches are available to support environmental assessment, monitoring and management of resource extraction projects. These include remote sensing and molecular analyses.</p>
<p>Deploying the necessary tools and methods will help ensure development in northern Australia is sustainable. It will also inform efforts to protect groundwater habitats and stygofauna across the continent. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/victoria-quietly-lifted-its-gas-exploration-pause-but-banned-fracking-for-good-its-bad-news-for-the-climate-133923">Victoria quietly lifted its gas exploration pause but banned fracking for good. It’s bad news for the climate</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/155137/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jenny Davis receives funding from CSIRO’s Gas Industry Social and Environmental Research Alliance (GISERA) and the Department of Agriculture, Water and Environment for baseline environmental surveys in the Beetaloo Sub basin and the Roper River region.</span></em></p><p class="fine-print"><em><span>Daryl Nielsen receives funding from GISERA</span></em></p><p class="fine-print"><em><span>Gavin Rees receives funding from GISERA</span></em></p><p class="fine-print"><em><span>Stefanie Oberprieler does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We discovered 11 (and probably more) new species of stygofauna living in water underground. These animals are usually blind, beautifully translucent and long-limbed.Jenny Davis, Professor, Research Institute for Environment & Livelihoods, Charles Darwin University, Charles Darwin UniversityDaryl Nielsen, Principal Research Scientist, CSIROGavin Rees, Principal Research Scientist, CSIROStefanie Oberprieler, Research associate, Charles Darwin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1504962020-12-15T13:20:28Z2020-12-15T13:20:28ZVirgin births from parthenogenesis: How females from some species can reproduce without males<figure><img src="https://images.theconversation.com/files/374837/original/file-20201214-17-2nde3j.png?ixlib=rb-1.1.0&rect=0%2C0%2C5463%2C3006&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Getting the job done. A female Asian water dragon (Physignathus cocincinus) produced a daughter (left) without the assistance of a male. </span> <span class="attribution"><a class="source" href="https://nationalzoo.si.edu/news/scientists-confirm-facultative-parthenogenesis-smithsonians-national-zoos-asian-water-dragon">Skip Brown/Smithsonian’s National Zoo</a></span></figcaption></figure><p>An Asian water dragon hatched from an egg at the Smithsonian National Zoo, and her keepers were shocked. Why? Her mother had never been with a male water dragon. Through genetic testing, zoo scientists discovered the newly hatched female, born on Aug. 24, 2016, had been produced through a <a href="https://doi.org/10.1371/journal.pone.0217489">reproductive mode called parthenogenesis</a>.</p>
<p>Parthenogenesis is a Greek word meaning “virgin creation,” but specifically refers to female asexual reproduction. While many people may assume this behavior is the domain of science fiction or religious texts, parthenogenesis is <a href="https://doi.org/10.1038/sdata.2014.15">surprisingly common throughout the tree of life</a> and is found in a variety of organisms, including plants, insects, fish, reptiles and even birds. Because mammals, including human beings, require certain genes to come from sperm, <a href="https://doi.org/10.1159/000090812">mammals are incapable of parthenogenesis</a>.</p>
<h2>Creating offspring without sperm</h2>
<p>Sexual reproduction involves a female and a male, each contributing genetic material in the form of eggs or sperm, to create a unique offspring. The vast majority of animal species reproduce sexually, but females of some species are able to produce eggs <a href="https://www.britannica.com/science/parthenogenesis">containing all the genetic material required for reproduction</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A microscopic view of a translucent water flea show four round eggs inside." src="https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373966/original/file-20201209-19-1x4523.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A female freshwater water flea (<em>Daphnia magna</em>) carrying parthenogenetic eggs.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/microscopic-view-of-freshwater-water-flea-royalty-free-image/841300586">buccaneership/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Females of these species, which include <a href="https://doi.org/10.1002/evl3.30">some wasps</a>, <a href="https://doi.org/10.1086/283761">crustaceans</a> and <a href="https://www.scientificamerican.com/article/asexual-lizards/">lizards</a>, reproduce only through parthenogenesis and are called obligate parthenogens.</p>
<p>A larger number of species experience spontaneous parthenogenesis, best documented in animals kept in zoo settings, like the Asian water dragon at the National Zoo or a <a href="https://doi.org/10.1111/j.1095-8649.2008.02018.x">blacktip shark at the Virginia Aquarium</a>. Spontaneous parthenogens typically reproduce sexually, but may have occasional cycles that produce developmentally ready eggs.</p>
<p>Scientists have learned <a href="https://doi.org/10.1098/rspb.2009.2113">spontaneous parthenogenesis may be a heritable trait</a>, meaning females that suddenly experience parthenogenesis might be more likely to have daughters that can do the same.</p>
<h2>How can females fertilize their own eggs?</h2>
<p>For parthenogenesis to happen, <a href="https://doi.org/10.1534/g3.112.005421">a chain of cellular events must successfully unfold</a>. First, females must be able to create egg cells (oogenesis) without stimulation from sperm or mating. Second, the eggs produced by females need to begin to develop on their own, forming an early stage embryo. Finally, the eggs must successfully hatch. </p>
<p>Each step of this process can easily fail, particularly step two, which requires the chromosomes of DNA inside the egg to double, ensuring a full complement of genes for the developing offspring. Alternatively, the egg can be “faux fertilized” by leftover cells from the egg production process known as <a href="https://doi.org/10.1002/mrd.21266">polar bodies</a>. Whichever method kicks off the development of the embryo <a href="https://doi.org/10.1525/bio.2009.59.7.3">will ultimately determine the level of genetic similarity</a> between the mother and her offspring.</p>
<p>The events that trigger parthenogenesis are not fully understood, but appear to include environmental change. In species that are capable of both sexual reproduction and parthenogenesis, such as <a href="https://doi.org/10.1371/journal.pone.0115099">aphids</a>, stressors like <a href="https://doi.org/10.1111/een.12080">crowding and predation</a> may cause females to switch from parthenogenesis to sexual reproduction, but not the other way around. In at least one <a href="https://doi.org/10.1007/978-90-481-2770-2_15">type of freshwater plankton</a>, <a href="https://doi.org/10.5762/KAIS.2016.17.4.692">high salinity</a> appears to cause the switch.</p>
<h2>Advantages of self-reproduction</h2>
<p>Though spontaneous parthenogenesis appears to be rare, it does provide some benefits to the female who can achieve it. In some cases, it can allow females to generate their own mating partners. </p>
<p>The sex of parthenogenetic offspring is determined by the same method sex is determined in the species itself. For organisms where sex is determined by chromosomes, like the XX female and XY male chromosomes in some insects, fish and reptiles, a parthenogenetic female can produce offspring only with the sex chromosomes she has at hand – which means she will always produce XX female offspring. But for organisms where females have ZW sex chromosomes (such as in snakes and birds), all living offspring produced will either be ZZ, and therefore male, or <a href="https://doi.org/10.1098/rsbl.2010.0793">much more rarely, WW, and female</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"976632933531316224"}"></div></p>
<p>Between 1997 and 1999, <a href="https://doi.org/10.1111/j.1095-8312.2012.01954.x">a checkered gartersnake kept at the Phoenix Zoo</a> gave birth to two male offspring that ultimately survived to adulthood. If a female mated with her parthenogenetically produced son, it would constitute inbreeding. While inbreeding can result in a host of genetic problems, from an evolutionary perspective it’s better than having no offspring at all. The ability of females to produce male offspring through parthenogenesis also suggests that asexual reproduction in nature may be more common than scientists ever realized before. </p>
<p>Biologists have observed, over long periods of time, that <a href="https://doi.org/10.1016/0022-5193(71)90058-0">species that are obligate parthenogens frequently die out</a> from <a href="https://doi.org/10.1038/s41514-018-0025-3">disease</a>, <a href="https://doi.org/10.1073/pnas.87.9.3566">parasitism</a> or <a href="https://doi.org/10.1002/evl3.30">changes in habitat</a>. The inbreeding inherent in parthenogenetic species appears to contribute to their short evolutionary timelines. </p>
<p>Current research on parthenogenesis seeks to understand why some species are capable of both sex and parthenogenesis, and whether occasional sexual reproduction might be enough for a species to survive.</p><img src="https://counter.theconversation.com/content/150496/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mercedes Burns has previously received funding from the National Science Foundation. </span></em></p>Parthenogenesis, a form of reproduction in which an egg develops into an embryo without being fertilized by sperm, might be more common than you realized.Mercedes Burns, Assistant Professor of Biological Sciences, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1461042020-12-02T19:09:12Z2020-12-02T19:09:12ZFreaky ‘frankenprawns’: ancient deep sea monsters called radiodonts had incredible vision that likely drove an evolutionary arms race<figure><img src="https://images.theconversation.com/files/365975/original/file-20201028-15-xtazrw.jpg?ixlib=rb-1.1.0&rect=6%2C20%2C4653%2C3472&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The radiodont _Anomalocaris_, with its large stalked eyes, is considered a top predator that swam in the oceans more than 500 million years ago.</span> <span class="attribution"><span class="source">Katrina Kenny</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Deep sea animals can be the stuff of nightmares.</p>
<p>Many inhabit the ocean’s twilight zone (down to 1,000 metres depth), where sunlight has virtually disappeared, and have adapted their vision to this dark alien world. Evolution gave them large, complex eyes to see in dim light — examples include the <a href="https://ocean.si.edu/ocean-life/invertebrates/vampire-squid-hell">Vampire Squid</a>, <a href="https://australian.museum/learn/animals/fishes/sloanes-viperfish-chauliodus-sloani/">Sloane’s Viperfish</a>, and various <a href="https://ocean.si.edu/ocean-life/invertebrates/phronima">predatory crustaceans</a>.</p>
<p>But how far back in prehistoric time do these scary, sharp-eyed creatures go?</p>
<p>Our study, <a href="https://advances.sciencemag.org/content/6/49/eabc6721">published today in Science Advances</a> looked at radiodonts (meaning “radiating teeth”) — a type of ancient <a href="https://australian.museum/learn/animals/what-are-arthropods/">arthropod</a> (animals with jointed legs but no backbone). </p>
<p>We found they developed sophisticated eyes more than 500 million years ago, and some were adapted to the dim light of deep water.</p>
<p>Our study provides new information about the evolution of the earliest marine animal ecosystems. </p>
<p>In particular, it supports the idea that vision played a crucial role during the <a href="https://www.nature.com/news/what-sparked-the-cambrian-explosion-1.19379">Cambrian Explosion</a>, a pivotal phase in history when most major animal groups (including <a href="https://theconversation.com/the-oldest-fish-in-the-world-lived-500-million-years-ago-27710">the oldest fish</a>) first appeared during a rapid burst of evolution.</p>
<p>Once complex visual systems arose, animals could better sense their surroundings. That may have fuelled an evolutionary arms race between predators and prey. Once established, vision became a driving force in evolution and helped shape the biodiversity and ecological interactions we see today.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C3132%2C1044&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C3132%2C1044&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/364394/original/file-20201020-21-10nmzmf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radiodonts face off. These bizarre animals from the Cambrian Period (over 500 million years ago) have some of the largest and most lens-rich compound eyes to have ever existed.</span>
<span class="attribution"><span class="source">Katrina Kenny</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/life-quickly-finds-a-way-the-surprisingly-swift-end-to-evolutions-big-bang-110984">Life quickly finds a way: the surprisingly swift end to evolution's big bang</a>
</strong>
</em>
</p>
<hr>
<h2>A brief guide to radiodonts</h2>
<p>Radiodonts are weird animals. Now extinct, they once dominated the oceans, especially during the Cambrian Period (541 million to 485 million years ago).</p>
<p>Some of the first radiodont fossils discovered more than a century ago were isolated body parts, and initial attempts at <a href="http://www.australasianscience.com.au/article/issue-julyaugust-2012/earth%E2%80%99s-first-super-predators.html">reconstructions</a> resulted in some “Frankenstein’s monsters”.</p>
<p>But over the past few decades many new discoveries — including whole radiodont bodies — have given a clearer picture of their anatomy, diversity and possible lifestyles. Nevertheless, complete radiodonts still look like something from science fiction!</p>
<p>There are many species of radiodonts and they share a similar body layout. </p>
<p>The head has a pair of large, segmented appendages for capturing prey, a circular mouth with serrated teeth, and a pair of eyes. The rest of the body looks rather like that of a squid. </p>
<p>It might sound like a <a href="https://www.merriam-webster.com/dictionary/chimera">chimera</a> of different animal parts, but the jointed appendages and <a href="https://en.wikipedia.org/wiki/Compound_eye">compound eyes</a> allow us to classify radiodonts as arthropods, which include insects, spiders and crabs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An isolated head appendage of _Anomalocaris_ _canadensis_" src="https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/364407/original/file-20201020-21-8cr2ld.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An isolated head appendage of <em>Anomalocaris canadensis</em> from the Burgess Shale of Canada.</span>
<span class="attribution"><span class="source">John Paterson</span></span>
</figcaption>
</figure>
<p>Over the past decade, new radiodont fossils have revealed a surprising variety of forms and enhanced our understanding of how they lived and especially how they fed.</p>
<p>One genus of radiodont, <em>Anomalocaris</em>, has long been considered an apex predator, akin to the modern great white shark. It had a large body, more than 50 centimetres long, and very strong, spiny head appendages it used for catching prey. It swam by undulating flaps on the sides of its body.</p>
<p>However, other radiodonts were gentle giants, such as the two-metre-long genus <em><a href="https://theconversation.com/fossils-of-huge-plankton-eating-sea-creature-shine-light-on-early-arthropod-evolution-38520">Aegirocassis</a></em>, which used its appendages for filtering plankton.</p>
<h2>All the better to see you with</h2>
<p>Despite the recent surge in knowledge about these awesome arthropods, little was known about the optics of radiodont eyes. In 2011, we published two papers in the journal Nature on fossil compound eyes from the 513-million-year-old Emu Bay Shale on Kangaroo Island, South Australia. </p>
<p>The <a href="https://www.nature.com/articles/nature10097">first paper</a> documented isolated eye specimens (up to 1 cm in diameter) that could not then be assigned to a known arthropod species. The second paper reported the <a href="https://www.nature.com/news/an-eye-opening-fossil-1.9586">stalked eyes of <em>Anomalocaris</em></a> in spectacular detail. </p>
<p>Since then, we have amassed a much larger collection of eyes from the Emu Bay Shale, shedding new light on radiodont vision.</p>
<p>Importantly, our new study identifies the owner of the eyes from our first 2011 paper: ‘<em>Anomalocaris</em>’ <em>briggsi</em> — the inverted commas indicate that it represents a new genus yet to be formally named. </p>
<p>We discovered much larger specimens of these eyes (up to 4 cm in diameter). They possess a distinctive “acute zone” — enlarged lenses in the centre of the eye’s surface that enhance light capture and resolution.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&rect=13%2C0%2C4646%2C3500&q=45&auto=format&w=1000&fit=clip"><img alt="An artist's reconstruction of '_Anomalocaris_' _briggsi_." src="https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&rect=13%2C0%2C4646%2C3500&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/357818/original/file-20200914-14-1l5739e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An artist’s reconstruction of ‘<em>Anomalocaris</em>’ <em>briggsi</em> swimming within the twilight zone.</span>
<span class="attribution"><span class="source">Katrina Kenny</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Radiodont eyes are also extremely sensitive. A single eye of <em>Anomalocaris</em> aff. <em>canadensis</em> — “aff.” meaning “affinity”, as it is closely related to this Canadian species — with more than 24,000 lenses, is rivalled only by certain insects such as dragonflies. These make it a highly visual, shallow-water predator, capturing prey with appendages bearing barbed spines. </p>
<p>The large lenses of ‘<em>Anomalocaris</em>’ <em>briggsi</em> suggest it could see in very dim light at depth, similar to <a href="https://www.youtube.com/watch?v=09BT1Qr4xqo">amphipod crustaceans</a>, a type of prawn-like creature that exists today. The frilly spines on its appendages filtered plankton that it detected by looking upwards. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The eye of '_Anomalocaris_' _briggsi_." src="https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=166&fit=crop&dpr=1 600w, https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=166&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=166&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=208&fit=crop&dpr=1 754w, https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=208&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/364402/original/file-20201020-13-1n2vgwa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=208&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The eye of ‘<em>Anomalocaris</em>’ <em>briggsi</em>. Left: complete fossil eye (scale bar is 5 mm); middle: close-up of lenses (scale bar is 0.5 mm); right: artist’s reconstruction showing the ‘acute zone’ of enlarged lenses, allowing it to see in dim light.</span>
<span class="attribution"><span class="source">John Paterson</span></span>
</figcaption>
</figure>
<p>The compound eyes of the two radiodonts from the Emu Bay Shale are outliers among arthropods, living or extinct. Their sheer size places them among the largest arthropod eyes ever.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/final-frontiers-the-deep-sea-13270">Final frontiers: the deep sea</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/146104/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Paterson receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Diego C. García-Bellido works for the University of Adelaide and the South Australia Museum. He has received funding from the Australian Research Council and the Spanish Ministry of Science (under its various names) towards the work presented in this article.</span></em></p><p class="fine-print"><em><span>Greg Edgecombe receives funding from the Australian Research Council. </span></em></p>Our study on weird ancient marine animals called radiodonts supports the idea that vision played a crucial role during the Cambrian Explosion, a rapid burst of evolution about 500 million years ago.John Paterson, Professor of Earth Sciences, University of New EnglandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1509042020-11-26T14:50:09Z2020-11-26T14:50:09ZInvasive species: biggest threat may be the most uncertain – disease<figure><img src="https://images.theconversation.com/files/371526/original/file-20201126-17-1lbbjhg.jpg?ixlib=rb-1.1.0&rect=0%2C189%2C2694%2C1573&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A cockroach.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/australian-cockroach-white-background-1856536435">Dawn Photos/Shutterstock</a></span></figcaption></figure><p>Showering celebrities with cockroaches, spiders and other exotic bugs might have seemed fun in Australia, but it’s a different story when the bushtucker trials move to Wales. Police are investigating <a href="https://www.theguardian.com/environment/2020/nov/24/welsh-police-investigate-im-a-celebrity-non-native-species-aoe">I’m a Celebrity, Get Me Out Of Here</a> because of concerns that <a href="https://www.theguardian.com/environment/2020/nov/26/bugs-that-escape-im-a-celebrity-could-cause-severe-problems-says-chris-packham-aoe">non-native wildlife</a> used in the ITV reality show – said to include cockroaches, whip scorpions, mealworms and crayfish – may be escaping into the Welsh countryside.</p>
<p>The UK is at constant risk of invasion by animals, plants, and microbes that haven’t evolved here. We can appreciate their potential environmental impact by comparing invasive species with oil spills. The effect of an oil spill is largely determined by the total amount of fuel that leaks, but it can be cleaned up and over time it becomes less severe. But when an alien species enters a new environment and is able to survive, its population can grow out of control and continue to spread and affect ecosystems long after the first release, eventually becoming difficult to control.</p>
<p>If even a few insects or spiders were to make it into the Welsh countryside, their population could grow and compete with – or even eat – native wildlife. This is what keeps invasive species biologists up at night. Nests belonging to the invasive Asian hornet have been <a href="https://www.rspb.org.uk/our-work/our-positions-and-casework/our-positions/species/invasive-non-native-species/asian-hornets/#:%7E:text=The%20Asian%20hornet%20is%20a,a%20significant%20predator%20of%20bees.&text=It%20has%20been%20recorded%20in,(as%20of%20January%202018).">recorded at least three times</a> in the UK. If this species were to gain a foothold, it could pose a major health risk to people and decimate native bee populations.</p>
<p>You only need to visit your local park to see what a successful invasion can mean for native wildlife. You might spot an invasive grey squirrel, but you’re far less likely to see a native red squirrel almost anywhere in the UK. The key to grey squirrels colonising the British Isles wasn’t simply that they turned up and pushed the reds out. The greys used biological warfare – transmitting a deadly disease to red squirrels called the squirrel pox virus. </p>
<p>This is the unknown factor that scientists fear most. We can anticipate and prepare for an invasive species that acts as a new predator or competitor for native wildlife. But how do we begin to prepare for the myriad diseases that they might carry?</p>
<h2>Hitchhikers on invasive species</h2>
<p>Invasive species can carry all kinds of diseases. If an animal or plant brings with it an unfamiliar virus, bacteria or other microorganism, it might infect local species. The crayfish plague, caused by a fungal parasite carried by invasive signal crayfish from North America, has <a href="https://cdn.buglife.org.uk/2019/05/Crayfish-in-crisis-FinalDoc2.pdf">killed large numbers</a> of the UK’s native white clawed crayfish. When crayfish plague hits a stream or river, you’ll know within the day as dead crayfish wash up.</p>
<p>While a spokesperson for I’m a Celebrity, Get Me Out Of Here was <a href="https://www.mirror.co.uk/tv/tv-news/im-celebrity-bosses-defend-use-23065778">reported as insisting</a> that the bugs they use aren’t likely to cause a problem in the wild, first impressions can be deceiving. We can’t predict how a non-native species will behave in a new environment. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1331589803243151360"}"></div></p>
<p>Our work at the <a href="https://research.tees.ac.uk/en/persons/jamie-bojko">National Horizons Centre</a> of Teesside University explores how invasive parasites, such as viruses and bacteria, evolve and interact with native species when introduced to somewhere new. Their spread and impact can vary depending on the type of parasite and the species it infects. In some cases, like the squirrels and crayfish, the disease can cause no symptoms in the invasive host, but can kill the native species. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/invasive-species-why-britain-cant-eat-its-way-out-of-its-crayfish-problem-147961">Invasive species: why Britain can't eat its way out of its crayfish problem</a>
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<p>In others, diseases can actually control the invaders, and stop them from causing too much damage. The invasive demon shrimp caused a great deal of alarm when it was <a href="https://canalrivertrust.org.uk/enjoy-the-waterways/canal-and-river-wildlife/the-rogues-gallery-of-invasive-species/killer-and-demon-shrimp">discovered in the UK</a> in 2012. We recently discovered a novel <a href="https://www.nature.com/articles/s41598-020-71776-3">nudivirus</a>, which appears to alter the behaviour of demon shrimp in their non-native habitat, making infected animals more active and potentially increasing their ability to spread both the virus and themselves. But we’ve also found parasites that can control the population by making the shrimp sick, including a spore-forming fungus known as <a href="https://pubmed.ncbi.nlm.nih.gov/25929755/"><em>Cucumispora ornata</em></a>. These examples highlight the critical role invisible hitchhikers play in the invasion process, either exacerbating or limiting the colonising capabilities of their animal hosts.</p>
<figure class="align-center ">
<img alt="A small, pale shrimp suspended in water." src="https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371529/original/file-20201126-19-1uuls72.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Demon shrimp may not look like much, but they could spell bad news for native crustaceans.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/demon-shrimp-swimming-water-1676441461">Jack Perks/Shutterstock</a></span>
</figcaption>
</figure>
<p>Despite their obvious importance, we know worryingly little about these <a href="https://www.sciencedirect.com/science/article/pii/S0022201120301889">parasites in invasive arthropods</a> – the invertebrate animals which include insects, arachnids and crustaceans. That leaves us in the dark about the potential diseases new invaders can carry. Less than a third of invasive species we studied have been screened for parasites, and there remains a lot of uncertainty around how diverse these parasites are, which invasive species can carry them and whether their introductions could harm native wildlife.</p>
<p>The furore around I’m a Celebrity’s non-native insects should set an example. Other industries, including the trade in ornamental species and tourism, have adjusted to accommodate the risk of spreading invasive species. Now we need much better security measures for television programmes that use wildlife, to prevent non-native species escaping sets and ending up on our doorsteps.</p><img src="https://counter.theconversation.com/content/150904/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jamie Bojko is an editor for two biological invasion journals.</span></em></p><p class="fine-print"><em><span>Amy Burgess does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The reality TV show I’m a Celebrity, Get Me Out Of Here is under fire for using non-native insects while filming in the Welsh countryside.Jamie Bojko, Lecturer in Biology, Teesside UniversityAmy Burgess, PhD Candidate in Invasion Biology, Teesside UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1479612020-10-13T15:25:33Z2020-10-13T15:25:33ZInvasive species: why Britain can’t eat its way out of its crayfish problem<figure><img src="https://images.theconversation.com/files/363125/original/file-20201013-23-k6zxf7.jpg?ixlib=rb-1.1.0&rect=0%2C187%2C4176%2C2588&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/signal-crayfish-pacifastacus-leniusculus-527341456">Marek R. Swadzba/Shutterstock</a></span></figcaption></figure><p>Invasive species pose a <a href="https://theconversation.com/invasive-species-threaten-most-protected-areas-across-the-world-new-study-140212">major threat</a> to global biodiversity. In the UK, one of the most notorious of these invaders is the signal crayfish, <em>Pacifastacus leniusculus</em>. Introduced from the US in the 1970s to be reared in farms for restaurants and food shops, this species quickly became established in the wild. Accidental and intentional releases helped them spread throughout British rivers and streams and today, they’re prevalent across the UK and continental Europe.</p>
<p>Signal crayfish have been so successful at invading because they produce a lot of offspring and eat almost anything, from detritus and aquatic plants to small invertebrates, fish and even each other.</p>
<p>Their extensive <a href="https://theconversation.com/how-tiny-creatures-are-reshaping-the-very-rivers-they-live-in-124845">burrowing has eroded</a> river banks throughout the UK, and they pose a grave threat to native wildlife, including Britain’s only native crayfish species, the white-clawed crayfish (<em>Austropotamobius pallipes</em>). Signal crayfish carry a disease known as crayfish plague, which is <a href="https://www.independent.co.uk/environment/native-british-crayfish-facing-extinction-following-mysterious-outbreak-plague-9679317.html">100% lethal</a> to the native white-clawed if contracted. But even signal crayfish free of the disease tend to outcompete their native counterparts over time. Pollution also threatens white-clawed crayfish across much of their range, and as a result, they have suffered tremendous declines, estimated at <a href="https://www.iucnredlist.org/species/2430/9438817">over 90%</a> in some English counties, leaving them vulnerable to extinction. </p>
<figure class="align-center ">
<img alt="A small crayfish with a white underbelly is pinched between a thumb and forefinger above a gravelly river bed." src="https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=530&fit=crop&dpr=1 600w, https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=530&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=530&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=666&fit=crop&dpr=1 754w, https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=666&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/363153/original/file-20201013-23-1pxrpit.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=666&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Also known as the European freshwater crayfish, the white-clawed crayfish is endangered.</span>
<span class="attribution"><span class="source">Eleri Pritchard</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>One method that’s used to try and control signal crayfish is trapping. Baited traps, similar to lobster pots, are placed in rivers to catch and remove them from the environment. Conservationists and well-meaning members of the public have been doing this for decades. Given signal crayfish arrived in the UK as food, the “eat them to beat them” strategy would seem to make sense. Even celebrity chefs have encouraged this kind of wild foraging, but does it actually work? In a <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.13758">new study</a>, we found an answer.</p>
<h2>No rock unturned</h2>
<p>Before we could understand if trapping worked, we needed to find out exactly how many crayfish were living in a stream and what these populations looked like. This was no easy task. Trapping tends to gather large, roaming males and spare the smaller, more cautious females, giving a skewed impression of the population.</p>
<figure class="align-center ">
<img alt="A large crayfish sits atop a black trap, similar to a lobster pot." src="https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=604&fit=crop&dpr=1 600w, https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=604&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=604&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=759&fit=crop&dpr=1 754w, https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=759&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/363157/original/file-20201013-21-1lx2b0s.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=759&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Traps like this one are used to catch and remove signal crayfish throughout Britain’s rivers.</span>
<span class="attribution"><span class="source">Eleri Pritchard</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We had to develop a whole new method, and we tested it at a rocky upland stream in the Yorkshire Dales where signal crayfish were illegally introduced in the 1990s. We completely drained short sections of streams and removed all the boulders and cobbles from the river bed, exposing any invasive crayfish in the process. We drained and re-wetted the area three times using pumps, and caught fewer crayfish each time. </p>
<p>As their numbers were depleted, we could accurately measure the total number of crayfish and estimate how many were likely still hiding in the riverbed. This method revealed densities of up to 110 crayfish per square metre in places, far exceeding any previous record for British waters. </p>
<p>Perhaps most surprising was the overwhelming number of small crayfish we found. In fact, less than 2.5% of all the signal crayfish we recorded were large enough to be caught in conventional traps. This species reaches breeding age before they’re “trappable” size, so populations can still reproduce and proliferate despite our best efforts to trap them. Large signal crayfish have been shown to cannibalise and eat small crayfish, so removing these larger cannibals with traps could inadvertently allow the population to grow even bigger.</p>
<figure class="align-center ">
<img alt="A crayfish with lots of eggs beneath the abdomen is held between a thumb and forefinger." src="https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/362982/original/file-20201012-15-z96tdk.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Signal crayfish can carry up to 250 eggs at a time.</span>
<span class="attribution"><span class="source">Eleri Prtichard</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Trapping causes other problems too. Many <a href="https://www.bbc.co.uk/news/uk-scotland-south-scotland-54424672">otters have drowned</a> after being caught in illegal crayfish traps. There are also concerns that signal crayfish, crayfish plague and other invasive species could hitch a ride between waterways on the surfaces of these traps. Our research adds to mounting evidence that trapping invasive crayfish is probably causing more harm than good.</p>
<p>As with many invasive species, the best thing we can do for now is to prevent their further spread by meticulously cleaning equipment and <a href="http://www.nonnativespecies.org/checkcleandry/index.cfm">following best practice</a> when around freshwater habitats. It’s disappointing that we’re no closer to a solution. But the idea that eating tasty crayfish helps control their numbers in the wild is sadly too good to be true.</p><img src="https://counter.theconversation.com/content/147961/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eleri G. Pritchard receives funding from the Natural Environment Research Council through the London NERCT DTP. Her PhD research is also supported by PBA Applied Ecology Ltd.</span></em></p>We found that signal crayfish traps tend to catch larger males, letting the bulk of the population go free.Eleri G. Pritchard, PhD Candidate in Freshwater Ecology, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1429222020-08-03T19:59:44Z2020-08-03T19:59:44ZFrom superheroes to the clitoris: 5 scientists tell the stories behind these species names<figure><img src="https://images.theconversation.com/files/350783/original/file-20200803-20-1vd8peq.png?ixlib=rb-1.1.0&rect=4%2C6%2C1017%2C504&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Left: imdb. Right: Volker Framenau </span></span></figcaption></figure><p>Weaving creative, heartfelt or even risqué words into the formal Latin names for new species has long been common in taxonomy — the science of classifying flora and fauna. </p>
<p>An 18th century botanist, for example, named a genus of flower “<a href="https://www.fnps.org/assets/pdf/palmetto/v13i4p8austin.pdf"><em>Clitoria</em></a>” after the human clitoris, and some scientists have named species after celebrities, or their loved ones. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The back of a fly with a striking resemblance to Deadpool's mask " src="https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=961&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=961&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=961&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1208&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1208&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350777/original/file-20200803-24-7yrdwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1208&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The ‘Deadpool fly’ went viral last week for its striking resemblance to the Marvel superhero.</span>
<span class="attribution"><span class="source">Isabella Robinson/CSIRO</span></span>
</figcaption>
</figure>
<p>In any case, naming a species is the first step to understanding and protecting our precious biodiversity. Only <a href="https://www.science.org.au/support/analysis/decadal-plans-science/discovering-biodiversity-decadal-plan-taxonomy">30% of the world’s species have been named</a> and many are lost to climate change, deforestation and introduction of invasive species before ever being known to science.</p>
<p>Here, five experts tell the stories behind species they’ve named or researched, from a Hugh Jackman-esque spider to a tiny crustacean named for the researcher’s partner’s swimming prowess. </p>
<h2>Wolverine (Wolf) spider, <em>Tasmanicosa hughjackmani</em></h2>
<h4>Volker Framenau</h4>
<p><a href="https://www.mapress.com/j/zt/article/view/zootaxa.4213.1.1">This wolf spider species</a> honours the Australian actor Hugh Jackman, who played Wolverine in the X-Men film series. I named the spider in 2016 after Jackman’s extraordinary artistic skills, and for his numerous philanthropic activities. </p>
<p>Of course, wolf spiders are much more remarkable than wolverines. For example, if you hold a torch or spotlight near your head, their sparkling green eyes reflect back into yours. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A big hairy spider with light brown limbs and black on its torso." src="https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350790/original/file-20200803-20-ffcv81.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">At night you might catch its sparkling green eyes reflected in your light.</span>
<span class="attribution"><span class="source">Volker Framenau</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>They can orientate using polarised light, even in the absence of direct sunshine or moonlight. This allows spiders to position themselves along coastal or riverbank environments, without needing a direct view to water. </p>
<p>The wolverine spider can also “fly” using gossamer threads (their spider silk) to catch the wind. They also use multimodal (visual, chemical, percussive) communication. Their mothers carry their eggs and subsequently often hundreds of young on their back, and they can live without food for more than a year. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-funny-to-name-species-after-celebrities-but-theres-a-serious-side-too-95513">It's funny to name species after celebrities, but there's a serious side too</a>
</strong>
</em>
</p>
<hr>
<h2>Butterfly pea, <em>Clitoria ternatea</em></h2>
<h4>Michelle Colgrave</h4>
<p>The genus name <em>Clitoria</em>, is taken from Latin, meaning “from a human female genital clitoris”. And if you look at the distinctive shape of the flower, you may be able to see why. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A purple flower with a yellow interior hangs off a stem," src="https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350775/original/file-20200803-16-8slzpl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The genus of the butterfly pea was named after the human clitoris.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>I’ve researched species within this genus, such as <em>Clitoria ternatea</em>, but it was 18th century Swedish botanist Carl von Linne (or Carolus Linnaeus) who named it. Linnaeus is credited with formalising “binomial nomenclature”, the way we name species today. And he was largely responsible for several rather ribald names, including orchids, named <em>Orchis</em> from the Greek word for “testicle”.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/oh-oh-oh-the-clitoris-certainly-gives-pleasure-but-does-it-also-help-women-conceive-126593">Oh, oh, oh! The clitoris certainly gives pleasure. But does it also help women conceive?</a>
</strong>
</em>
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<p><em>Clitoria ternatea</em>, or the butterfly pea, is a legume originating in Africa, but is now widespread through much of Asia and tropical regions in Australia. It was used in a variety of indigenous medicines throughout Asia ascribed with a range of activities, including anecdotal evidence of their use as an aphrodisiac.</p>
<p><em>Clitoria ternatea</em> has found numerous uses in Australia as a forage crop for grazing or for soil remediation. It is popular in horticulture for its bright blue flowers, and is revered in India as a holy flower. It’s also widely used in food and beverages — from rice to tea to cocktails and liqueurs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A purple-blue tea in a glass, filled with ice, beside butterfly pea flowers." src="https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350773/original/file-20200803-20-1ciui3t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Butterfly peas can be used for food and beverages, with a striking colour.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>More recently, it has been <a href="https://pubs.acs.org/doi/abs/10.1021/cb100388j">found</a> to offer protection from insect pests, and has been commercialised as <a href="http://cipps.org.au/outreach">Sero-X</a>, an eco-friendly insecticide.</p>
<p>If this sparks your interest, then you might also be interested in <em>Nepenthes</em> species or <em>Amorphophallus titanum</em>!</p>
<h2>The Beyoncé fly, <em>Plinthina beyonceae</em></h2>
<h4>Bryan Lessard</h4>
<p>Naming a species after a celebrity is a creative way to draw attention to a particular creature and taxonomy.</p>
<p>The first species I ever named was a golden horse fly from the Atherton Tableland in Queensland. It was originally collected in 1982, but there were no horse fly experts in the country to identify it, so it was archived in Australian natural history collections for 30 years.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up of a fly with translucent yellow wings" src="https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=830&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=830&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=830&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1043&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1043&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350776/original/file-20200803-18-1sfd0rq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1043&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Beyoncé fly, because Beyoncé is fly.</span>
<span class="attribution"><span class="source">Bryan Lessard</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Then, during my PhD in 2012, I immediately recognised it as a new species, and named it after <a href="https://www.abc.net.au/news/2012-01-13/horse-fly-named-after-beyonce/3771224">Beyoncé</a> since I was listening to a lot of her music while examining the species under the microscope. The specimens were even collected in the same year she was born!</p>
<p><em>Plinthina beyonceae</em>, its official name, sparked a global discussion on the importance of flies. And scientists are just starting to realise how important the Beyoncé fly and other horse flies are at pollinating some of our iconic native plants including eucalypts, tea trees and grevilleas.</p>
<p>Since the Beyoncé fly, our team at <a href="https://www.csiro.au/en/Research/Collections/ANIC">CSIRO</a> has been more imaginative in naming species. Our PhD student Xuankun Li recently named a species of a winter-loving bee fly with crown of thorn-like spines after the <a href="https://www.csiro.au/en/News/News-releases/2019/230-new-species-in-real-life-Game-of-Flies">Night King from Game of Thrones</a>. And just last week our undergraduate student Isabella Robinson named a heroic group of assassin flies after <a href="https://www.csiro.au/en/News/News-releases/2020/Deadpool-fly-among-new-species-named-by-CSIRO">Deadpool and other Marvel characters</a>.</p>
<h2><em>Mogurnda mosa</em></h2>
<h4>Aaron Jenkins</h4>
<p>I’ve been fortunate enough to discover, describe, and name several species new to Western science, including 11 new species of fishes. While many of these critters have legitimately avoided recognition in any language, several have long been known and named by local indigenous people.</p>
<p>So, to say I “discovered” and “named” them is blatantly untrue and pongs of colonial misappropriation of traditional knowledge. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350788/original/file-20200803-16-162loea.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lake Kutubu, where this fish was discovered.</span>
<span class="attribution"><span class="source">Ambok1/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>About 20 years ago I was the first person to SCUBA dive in Lake Kutubu — an exceptionally clear, high altitude lake in Southern Highlands in Papua New Guinea. As part of this marvellous experience I found several species of fishes new to Western science. One of which was a preferred food fish for the local Foe people, named “mosa” in Foe tokples (local language in Melanesian Pidgin). </p>
<p>In recognition of the tokples name of this species, I simply provided mosa as the species name in my scientific description. This new species is now named <em><a href="https://cdn.theconversation.com/static_files/files/1150/Jenkins_et_al_2000.pdf?1596433292">Mogurnda mosa</a></em> in Western science, combining “Mogurnda”, which is an Aboriginal name used in Australia, and the tokples name “mosa”. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=233&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=233&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=233&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=293&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=293&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350784/original/file-20200803-18-10yqpz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=293&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The <em>Mogurnda mosa</em> fish, found in Papua New Guinea.</span>
<span class="attribution"><span class="source">Western Australian Museum Field Guides and Catalogues</span></span>
</figcaption>
</figure>
<p>This fish is a true indigenous species of Oceania, named to honour the original names of the traditional custodians. But oil and gas drilling around the lake significantly threatens the entire known, critically endangered population. Additional threats include invasive species.</p>
<h2>Moody’s swamp amphipod, <em>Kartachiltonia moodyi</em></h2>
<h4>Rachael King</h4>
<p>Finding tiny crustaceans in unusual places is one of the best parts of my work as a research scientist. I’ve trawled the deep-sea floor on big oceanographic vessels, fished down bore holes in arid deserts, and dug in swamps, seeps and springs in the outback — all in an effort to find new species.</p>
<p>In 2009 my colleague and I travelled to Kangaroo Island and collected specimens from a new site to us — a spring-fed swamp near Rocky River. The specimens ended up being a new genus and species of amphipod, which we called <em><a href="https://www.publish.csiro.au/zo/ZO13099">Kartachiltonia moodyi</a></em>. </p>
<p>The name breaks down roughly as “Karta” for the local Indigenous name of Kangaroo Island, and “chiltonia” for the family (Chiltoniidae) it belongs to.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A drawing of the crustacean in black outline." src="https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=345&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=345&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=345&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=434&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=434&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350770/original/file-20200803-24-110s8oo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=434&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An illustration of the Moody’s swamp amphipod.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The last part to the species name was named after my partner, whose last name is Moody. This animal basically has a whole extra set of gills that no other Australian chiltoniid amphipods had — and my partner was a good competitive swimmer in his youth. It made perfect sense to me (Phar Lap had a <a href="https://www.nma.gov.au/explore/collection/highlights/phar-lap-collection">bigger heart</a>, right?!).</p>
<p>He’s quite happy to have a species named for him, and also happy any similarities weren’t based on something like a giant head or weirdly shaped feet (neither of which he, or the amphipod, has).</p>
<p>And with the recent bushfires roaring through this swamp area on Kangaroo Island, we have been on tenterhooks to see if the species managed to survive. This week we’ve managed to get some samples from nearby, and it’s looking good, but I won’t know for sure until I get them under a microscope.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/click-through-the-tragic-stories-of-119-species-still-struggling-after-black-summer-in-this-interactive-and-how-to-help-131025">Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)</a>
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<img src="https://counter.theconversation.com/content/142922/count.gif" alt="The Conversation" width="1" height="1" />
From a Hugh Jackman-esque spider to honouring traditional Indigenous words, these species have memorable names.Anthea Batsakis, Deputy Environment + Energy Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1437032020-07-31T15:06:00Z2020-07-31T15:06:00ZMicroplastics: tiny crustaceans can fragment them into even smaller nanoplastics<figure><img src="https://images.theconversation.com/files/350624/original/file-20200731-23-1tdc3uv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Gammarus duebeni, the shrimp-like animal that can break down microplastic.</span> <span class="attribution"><span class="source">Alicia Mateos Cárdenas</span>, <span class="license">Author provided</span></span></figcaption></figure><p><a href="https://theconversation.com/uk/topics/microplastics-17592">Microplastics are widespread</a> in seas and oceans, and their <a href="https://theconversation.com/how-microplastics-make-their-way-up-the-ocean-food-chain-into-fish-69148">harmful effects</a> on many different marine animals are well known. However, we know relatively little about the microplastics in our freshwater rivers, streams and lakes. We still don’t know exactly where they come from, where they end up – and crucially – what damage they can cause if they get into food chains.</p>
<p>Until now, plastic fragmentation had largely been attributed to processes such as sunlight or wave action, which can take years or decades. But it turns out a tiny shrimp-like creature can do the same job much faster. </p>
<p>I am a researcher who specialises in microplastics in the environment. In my latest study, colleagues and I have shown that microplastics (plastic pieces smaller than 5mm) in freshwaters are being broken down into even smaller nanoplastics (smaller than one micrometre, at least five thousand times smaller in size) by a type of freshwater invertebrate animal, and that this may happen much faster than previously estimated. Our results, newly published in the Nature journal <a href="http://www.nature.com/articles/s41598-020-69635-2">Scientific Reports</a>, highlight the role of biological fragmentation of microplastics, which has been understudied so far.</p>
<p>The animal in question is a 2cm-long crustacean, the freshwater amphipod <em>Gammarus duebeni</em>. This specific species lives in Irish streams, but it belongs to a bigger group of invertebrates that are common in both freshwater and the oceans around the world. Our finding therefore has big consequences for how we understand the environmental fate of microplastics.</p>
<figure class="align-center ">
<img alt="A stream with trees lining the bank" src="https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350625/original/file-20200731-24-xuuo06.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Gammarus duebeni</em> lives in freshwater in Ireland, like this stream in County Cork.</span>
<span class="attribution"><span class="source">Alicia Mateos Cardenas</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Our first experiments had been carried out to understand the potential negative effects (if any) of microplastics in the amphipods. However, some surprising early results led me to run new experiments focused on gathering evidence to show that microplastics were being fragmented biologically – by <em>G. duebeni</em> themselves. </p>
<p>In order to find out about this, I exposed the amphipods in the laboratory to a certain type of microplastics that have a specific colour dye. I then dissected the digestive tracts of the amphipods and visualised them under a fluorescence microscope, which is able to track the dyed-microplastic in animal tissue.</p>
<p>We then concluded that <em>Gammarus duebeni</em> is able to fragment microplastics into different shapes and sizes, including nanoplastics, in less than four days.</p>
<p>We were able to track such fragmentation because the microplastics that we used were originally “microbeads” with a perfect spherical shape. Any plastic with irregular shapes therefore must have been fragmented by the animals, and nearly 66% of the microplastics found in the guts had indeed been fragmented in this way. </p>
<p>Remarkably, the proportion of smaller plastic fragments was highest when the amphipods were “purged” in the lab in a clean environment with no plastics but with their food. This finding indicates that biological fragmentation could be closely related to the feeding process. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopic images with glowing microplastic highlighted" src="https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=222&fit=crop&dpr=1 600w, https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=222&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=222&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=278&fit=crop&dpr=1 754w, https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=278&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/350626/original/file-20200731-19-uiyn59.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=278&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Left: two fragmented microplastics in an amphipod’s gut. Right: a nanoplastic fragment.</span>
<span class="attribution"><span class="source">Alicia Mateos Cardenas</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We also ran some quality control checks, several side experiments to make sure that the plastic was indeed being fragmented by the amphipods and not some other source, and that we were accurately visualising the fluorescence particles.</p>
<h2>Microplastics in the food chain</h2>
<p>Why does this matter? We already know that microplastics can accumulate in the gut of seabirds and fish, and our current understanding is that the smaller nanoplastic particles could even penetrate cells and tissues where their effects could be much harder to predict. </p>
<p>Therefore the finding that such a common animal can rapidly produce vast numbers of nanoplastics is particularly worrying. Since the crustaceans we looked at are eaten by fish and birds, any nanoplastic fragments that they produce may also be entering the food chain. </p>
<p>For example, scientists at the University of Cardiff recently showed for the first time that <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15139">microplastics had been transferred up the food chain in a river</a>, from small invertebrates through to dippers, the only songbird that can swim underwater. They looked at dipper regurgitates and faecal pellets from both adults and chicks and found microplastics in all of them. </p>
<p>We still don’t know exactly what effect this microplastic transfer will have on the birds, especially in the early stages of their lives. But our results on the biological fragmentation of microplastics will help us to understand the role that animals can have in determining the fate of plastics in our waters.</p><img src="https://counter.theconversation.com/content/143703/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>In this study, Alicia Mateos Cárdenas received funding from the Irish Environmental Protection Agency (EPA).
This project was funded under the EPA Research Programme 2014–2020. The EPA Research Programme is a Government of Ireland initiative funded by the Department of Communications, Climate Action and Environment. It is administered by the Environmental Protection Agency, which has the statutory function of co-ordinating and promoting environmental research. This UCC project was supervised by Professor Marcel Jansen, Dr Frank van Pelt and Professor John O’Halloran. </span></em></p>The discovery that such a common animal can rapidly produce vast numbers of nanoplastics is particularly worrying.Alicia Mateos Cárdenas, Postdoctoral Researcher, University College CorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1410422020-07-09T04:02:08Z2020-07-09T04:02:08Z‘Living fossils’: we mapped half a billion years of horseshoe crabs to save them from blood harvests<figure><img src="https://images.theconversation.com/files/345986/original/file-20200707-27858-x1kgcv.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C5160%2C3445&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>If you ventured to the New York seaside in summer, you might see a large dome-shaped animal with a spiky tail, slowly moving towards the water. These are horseshoe crabs – the animals time forgot.</p>
<p>Fossil records for horseshoe crabs extend back about 480 million years. This is well over 200 million years before the dinosaurs. </p>
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Read more:
<a href="https://theconversation.com/a-giant-species-of-trilobite-inhabited-australian-waters-half-a-billion-years-ago-118452">A giant species of trilobite inhabited Australian waters half a billion years ago</a>
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<p>More recently, horseshoe crabs have greatly helped advance modern medicine. Their blood is used to identify <a href="https://www.sciencedirect.com/topics/chemistry/endotoxin">endotoxins</a> in solutions. These are toxins found in bacteria, so anyone who has had an injection or surgery has been kept safe from dangerous toxins thanks to these creatures.</p>
<p>Unfortunately, the harvesting of their blood for this purpose is one reason horseshoe crabs are becoming an <a href="https://science.howstuffworks.com/life/biology-fields/horseshoe-crabs-endangered-biomedical-bloodletting.htm">endangered group</a>. Our <a href="https://www.frontiersin.org/articles/10.3389/feart.2020.00098/abstract">research</a> published today in Frontiers in Earth Science will hopefully aid conservation efforts to protect these enigmatic creatures.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342637/original/file-20200618-41200-1grm5ca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The American horseshoe crab <em>Limulus polyphemus</em>.</span>
<span class="attribution"><span class="source">WikiCommons.</span></span>
</figcaption>
</figure>
<h2>A modern medical marvel</h2>
<p>Completely harmless, but spiky like a cactus, horseshoe crabs are not actually crabs. They don’t have the antennae or jaws their crustacean cousins do, and have additional pairs of legs (13 in total). In fact, they’re more closely related to spiders and scorpions than crabs. </p>
<p>Defined within their own order, <a href="https://ucmp.berkeley.edu/arthropoda/chelicerata/xiphosura.html">Xiphosura</a>, these animals are characterised by a horseshoe-shaped head section, a roundish hexagonal backside and a long tail. They are, in essence, a spider in a suit of armour that can swim upside down. </p>
<p>Horseshoe crabs have been used in medicine for at least the <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2006607">past 40 years</a>. Their endotoxin-revealing blood is blue and copper-based (unlike our red, iron-based blood). </p>
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Read more:
<a href="https://theconversation.com/blood-in-your-veins-is-not-blue-heres-why-its-always-red-97064">Blood in your veins is not blue – here's why it's always red</a>
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<p>A chemical refined from their blood can be used to identify contaminants in medical equipment that is inserted into <a href="https://www.iflscience.com/plants-and-animals/how-horseshoe-crab-blood-saves-millions-lives/">humans</a>. </p>
<p>Blue blood is used to make sure injections, IV drips, and any implanted medical devices are safe for human use.</p>
<h2>Blue bloodletting</h2>
<p>However, to access this natural medicinal miracle, humans must collect horseshoe crabs and harvest their blood. While blood loss itself may not be the main cause of death, other factors such as capture and transport can impact group survival. </p>
<p>At present, with improved practices, between <a href="https://www.frontiersin.org/articles/10.3389/fmars.2018.00185/full?utm_source=FWEB&utm_medium=NBLOG&utm_campaign=ECO_FMARS_horseshoe-crab-blood#h11">6-15.4% </a> of horseshoe crabs die from harvesting.</p>
<p>This process represents one of the main threats to them today, even though a <a href="https://www.theatlantic.com/science/archive/2018/05/blood-in-the-water/559229/">synthetic substitute</a> for blue blood has been available for nearly two decades. However, there is uncertainty around the efficacy of this alternative, so horseshoe crabs are <a href="https://blogs.unimelb.edu.au/sciencecommunication/2019/10/22/horseshoe-crab-the-blue-blood-that-saves-millions-of-lives/">still harvested</a>.</p>
<p>As a result, two of the four living species – the Chinese horseshoe crab and American horseshoe crab (also called the Atlantic horseshoe crab) – have been placed on the <a href="https://www.iucnredlist.org/search?taxonomies=101493&searchType=species">International Union for Conservation of Nature’s</a> vulnerable and endangered species list.</p>
<p>Apart from bloodletting for biomedical use, <a href="https://www.nwf.org/Educational-Resources/Wildlife-Guide/Invertebrates/Horseshoe-Crab">other threats</a> facing horseshoe crabs include overharvesting, <a href="https://www.sciencedirect.com/science/article/pii/S2351989419306997">human interaction and serious habitat modification</a>.</p>
<h2>Fantastic beasts, and where to find them (online)</h2>
<p>To help raise awareness about the challenges horseshoe crabs face, we created an <a href="https://www.frontiersin.org/articles/10.3389/feart.2020.00098/abstract">atlas of all fossil and living Xiphosura</a>. This free, open access collection contains photos of every horseshoe crab species ever described in the group’s 480-million-year history. </p>
<p>Alongside the photos, we provide outlines of how the four living species survived until now. </p>
<p>Building this atlas took three years. It involved emailing more than 100 researchers and museum managers, and even travelling from Australia to England, Germany, Russia, Slovenia and the United States to collect photographs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=241&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=241&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=241&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=302&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=302&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342937/original/file-20200619-70381-16myyr1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=302&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Examples of fossil horseshoe crabs. Left to right: <em>Pickettia carteri</em>, <em>Albalimulus bottoni</em>, <em>Sloveniolimulus rudkini</em>, and <em>Tasmaniolimulus patersoni</em>.</span>
<span class="attribution"><span class="source">Reconstructions by Elissa Johnson and Katrina Kenny</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The result is an example of every single horseshoe crab species ever documented, living or extinct – more than 110 in total.</p>
<h2>The ‘living fossil’ that roamed with dinosaurs</h2>
<p>Our atlas can help highlight the unique and complex evolutionary history of horseshoe crabs. </p>
<p>These arthropods (invertebrates with an exoskeleton and jointed legs) survived all mass extinctions. Some have changed in appearance through time. For example, we have completely bizarre fossil forms, such as <em>Austrolimulus</em> – essentially a pick-axe in horseshoe crab form.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342654/original/file-20200618-41221-18cmqhd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Austrolimulus fletcheri</em> lived in the New South Wales area during the Triassic. They’re a truly unique species.</span>
<span class="attribution"><span class="source">Patrick Smith.</span></span>
</figcaption>
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<p>However, some fossil species look very similar to modern ones. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=973&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=973&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=973&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1223&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1223&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342656/original/file-20200618-41242-hdtdm7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1223&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"><em>Mesolimulus walchi</em>, from the Solnhofen Limestone in Germany.</span>
<span class="attribution"><span class="source">Russell Bicknell/Paläontologisches Museum, München specimen.</span></span>
</figcaption>
</figure>
<p>Compare the Jurassic-aged fossil <em>Mesolimulus</em>, found in <a href="https://en.wikipedia.org/wiki/Solnhofen_Limestone">Solnhofen Limestone</a> in Germany, to American horseshoe crabs walking along the North American coast today. They are practically the same. </p>
<p>Apart from size differences, horseshoes crabs have changed very little over the past 150 million years or so, earning them the moniker “living fossils”. But while specimens in the fossil record are between 3-30cm long, horseshoe crabs today can grow to more than 80cm.</p>
<p>Unfortunately, horseshoe crab populations have been decreasing significantly due to blood harvesting. There’s now <a href="https://www.theguardian.com/environment/2018/nov/03/horseshoe-crab-population-at-risk-blood-big-pharma">genuine concern</a> humans will drive these organisms to extinction.</p>
<p>Expanding our collective knowledge could help fuel future conservation efforts. Let’s prevent these unique icons of a bygone era from passing into the annals of history. </p>
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Read more:
<a href="https://theconversation.com/giant-sea-scorpions-were-the-underwater-titans-of-prehistoric-australia-141290">Giant sea scorpions were the underwater titans of prehistoric Australia</a>
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<img src="https://counter.theconversation.com/content/141042/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Russell Dean Christopher Bicknell received funding for this project in the following forms: a University of New England Post Doctoral Fellowship, Betty Mayne Scientific Research Fund, James R Welch Scholarship, and a Schuchert and Dunbar Grants in Aid Program. He is also a member of the International Union for the Conservation of Nature Horseshoe Crab Species Specialist Group.
</span></em></p><p class="fine-print"><em><span>Stephen Pates is a postdoctoral fellow funded by the Museum of Comparative Zoology, Harvard University.</span></em></p>A chemical refined from the blue, copper-based blood of horseshoe crabs helps identify contaminants in medical equipment inserted into humans.Russell Dean Christopher Bicknell, Post-doctoral researcher in Palaeobiology , University of New EnglandStephen Pates, Postdoctoral fellow, Harvard UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1412902020-07-03T04:51:52Z2020-07-03T04:51:52ZGiant sea scorpions were the underwater titans of prehistoric Australia<figure><img src="https://images.theconversation.com/files/345445/original/file-20200703-33943-igylzw.jpg?ixlib=rb-1.1.0&rect=22%2C10%2C1341%2C1012&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/3/3c/Eurypterus_Paleoart.jpg">Dimitris Siskopoulos/Wiki commonc</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Let’s turn back the hands of time. Before extinction knocked dinosaurs off their pillar, before the “<a href="https://www.theguardian.com/environment/2018/dec/06/global-warming-extinction-report-the-great-dying#:%7E:text=The%20mass%20extinction%2C%20known%20as,the%20dinosaurs%2065m%20years%20ago.">Great Dying</a>” extinction wiped out 95% of all organisms – we had the Paleozoic Era.</p>
<p>During this age in Earth’s history, between 541 million and 252 million years ago, arthropods (animals with exoskeletons such as insects, crustaceans, scorpions, and horseshoe crabs) were exploring the extremes of size, from tiny to huge. </p>
<p>In fact, some Paleozoic arthropods represent the largest animals on Earth at the time. If you were to take a swim in the Paleozoic oceans, you may have been fortunate (or unfortunate) enough to find one of the most fearsome of these extinct arthropods: the sea scorpions, Eurypterida. </p>
<p>Our new research, published in <a href="https://www.sciencedirect.com/science/article/pii/S1342937X20301799">Gondwana Research</a>, is the most comprehensive collection of information on these fascinating creatures that once roamed Australian waters.</p>
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<a href="https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344972/original/file-20200701-54152-1cab3hl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A <em>Eurypterus remipes</em> fossil. This sea scorpion existed more than 400 million years ago and was usually less than one foot in length, but relatives are believed to have reached up to eight feet.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=9008160">H. Zell/Wiki commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<h2>A sight to behold</h2>
<p>Although Eurypterida looked broadly like scorpions (with a similar body shape, albeit built for swimming), they were not. They were more like the cousins of modern scorpions.</p>
<p>An exceptional part of the sea scorpion evolutionary story is how they fit into the narrative of Paleozoic gigantism. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fossils-of-huge-plankton-eating-sea-creature-shine-light-on-early-arthropod-evolution-38520">Fossils of huge plankton-eating sea creature shine light on early arthropod evolution</a>
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<p>Sea scorpions include the largest marine predators to have ever arisen in the fossil record, including <a href="https://www.sciencedaily.com/releases/2007/11/071120195710.htm">one species</a> thought to have been more than 2.5 metres long, <em>Jaekelopterus rhenaniae</em>. Back then, some of these giants were effectively in the same place in their food web as the modern great white shark. </p>
<p>These likely agile swimmers would have used their large front limbs, armed with claws, to grab their prey, which they would then crush between the teeth-like structures on their legs (called gnathobasic spines). </p>
<p>While we’re not sure exactly what these large animals ate, it’s likely fish and smaller arthropods would have been on the menu. And if humans had been around swimming in the sea, maybe us too!</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=267&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=267&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=267&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=335&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=335&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344940/original/file-20200701-54182-25jcmp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=335&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The size of the largest extinct sea scorpions, relative to a human.</span>
<span class="attribution"><span class="source">Slate Weasel/Wiki commons. Modified.</span></span>
</figcaption>
</figure>
<h2>A fascinating (but murky) history</h2>
<p>Australia is famous for its array of curious animals, including unique modern species such as the platypus. And this uniqueness extends far into the fossil record, with sea scorpions being a case in point. </p>
<p>But the scientific record and study of Australian sea scorpions has been patchy. The first documented specimen, published <a href="https://doi.org/10.1017/S0016756800143249">in 1899</a>, consisted of a fragmented exoskeleton section found in Melbourne.</p>
<p>Prior to our new research examining the completeness of the group in Australia, there were about ten records – and only one other attempt to pool everything together. As such, the diversity and spread of these fossils was fairly uncertain. </p>
<p>For us, revisiting these amazing fossils resulted in a few trips to different Australian museums. We also had specimens sent to us at the University of New England to examine in person. </p>
<hr>
<p>
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<strong>
Read more:
<a href="https://theconversation.com/the-mighty-dinosaurs-were-bugged-by-other-critters-50390">The mighty dinosaurs were bugged by other critters</a>
</strong>
</em>
</p>
<hr>
<p>This journey of palaeontological discovery uncovered many sea scorpion fossils than hadn’t previously been noted. As a result, we now have evidence of a possible six different groups that existed in Australia.</p>
<p>Collating these specimens together in our most recent publication, we illustrate the Pterygotidae (the family of sea scorpions that reached 2.5 metres long) dominated the group’s Australian fossil record. Although this had been noted before, the abundance of material from different locations and time periods, especially from Victoria, was unexpected.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=241&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=241&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=241&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=303&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=303&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344946/original/file-20200701-54156-12n14c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=303&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Examples of Australian sea scorpion fossils, their two groups and the time range. Blue represents the family Pterygotidae and orange represents the family Adelophthalmidae.</span>
</figcaption>
</figure>
<h2>Back to the source</h2>
<p>Besides showcasing the largest number of Australian sea scorpions, our paper also outlines the overall lack of information on these animals. </p>
<p>Despite there being much fragmented material, there is only one (mostly) complete specimen, <em>Adelophthalmus waterstoni</em>, measuring just 5.7cm long.</p>
<p>Future research will involve revisiting the sites where these specimens were originally collected, in the hope of finding more complete specimens. Not only will this help document Australian sea scorpion species better, it will also allow for a more complete understanding of the environments in which they lived. </p>
<p>Ultimately, one thing is clear – there is much left to uncover about these titans that swam through Australia’s prehistoric oceans.</p>
<hr>
<p><em>The authors thank Natalie Schroeder Geoscience Australia for her help with this project.</em></p><img src="https://counter.theconversation.com/content/141290/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>During the Paleozoic Era, giant sea scorpions would have been the equivalent of a great white shark in their food web.Russell Dean Christopher Bicknell, Post-doctoral researcher in Palaeobiology , University of New EnglandPatrick Mark Smith, Technical Officer - Palaentology, Australian MuseumLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1317502020-02-18T19:01:17Z2020-02-18T19:01:17ZCoronavirus is killing Australia’s lobster export market<figure><img src="https://images.theconversation.com/files/315883/original/file-20200218-11017-1kk0gxe.jpg?ixlib=rb-1.1.0&rect=50%2C8%2C5568%2C3292&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Currents are strong around the Torres Strait Islands, lying between Australia’s northern-most tip and Papua New Guinea.</p>
<p>When the tidal conditions are right and the waters relatively still, though, up to 230 islanders – a sizeable percentage of the islands’ roughly 4,000 indigenous inhabitants – will board small boats and head out to the surrounding reefs. There they will dive down and search the underwater outcrops for lobsters, grabbing the crustaceans by hand.</p>
<p>It’s laborious work compared with lobster fishing in other parts of Australia, where fishers bait “pots”, then simply pull up the pots with lobsters inside. The tropical rock lobsters of the Torres Strait, however, are sensitive creatures and generally won’t crawl into a trap. By hand is the only sure way to catch them.</p>
<p>But, until a few weeks ago, it has been worth it. </p>
<p>A fisher can sell a live lobster from these waters for $65-95 a kilogram. That makes it worth holding them in water-filled crates and then flying them to wholesalers in Cairns. There they are processed and transported to domestic and international markets. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315870/original/file-20200218-11040-x6a67l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Tropical lobsters caught in Torres Strait.</span>
<span class="attribution"><span class="source">Eva Plaganyi-Lloyd</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The most lucrative market is China. Its appetite for live rock lobster makes up about half the value of Australia’s seafood exports (A$660 million of A$1.4 billion). </p>
<p>Now, though, lobster fishers are staying home. There hasn’t been a regular lobster shipment to China since January 26.</p>
<p>With the Wuhan coronavirus suspected to have <a href="https://www.cnbc.com/2020/02/11/coronavirus-likely-jumped-from-bats-to-another-host-before-infecting-humans-who.html">originated from wild animals in the city’s Huanan Seafood Wholesale Market</a>, Chinese authorities have temporarily banned all wild animal trade. Lobster and other wild-caught aquatic products are exempt from the ban, but demand has plummeted due to people staying home and avoiding both markets and restaurants.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fear-spreads-easily-thats-what-gives-the-wuhan-coronavirus-economic-impact-130780">Fear spreads easily. That's what gives the Wuhan coronavirus economic impact</a>
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<p>This collapse has come at a time that would normally be one of peak demand, and peak prices, due to Chinese New Year festivities. Our industry sources report prices for live lobsters are down 50% to 80%.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=428&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=428&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=428&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=538&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=538&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315426/original/file-20200214-11017-15b1v9i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=538&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An advertisement for rock lobsters in the Queensland Asian Business Weekly on January 31 2020, shows drastically reduced prices, from A$258 a kilogram to A$148 a kilogram, for large lobsters.</span>
<span class="attribution"><span class="source">Author supplied</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>It’s a huge blow to the economy of Torres Strait, along with the rest of Australia’s live seafood export industry.</p>
<h2>Loss of livelihoods</h2>
<p>Lobster fishing is among the <a href="http://www.tsra.gov.au/the-tsra/programmes/economic-development?a=11920">highest-value</a> economic activities in the strait. Indigenous islanders have limited alternatives to make money, given their geographical isolation. </p>
<p>As scientists fortunate to work closely with traditional owners in the Torres Strait over the past decade, we’re saddened to see this devastating impact on livelihoods. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=667&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=667&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=667&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=839&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=839&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315872/original/file-20200218-11000-1i4f0o9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=839&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Author Eva Plaganyi-Lloyd with a tropical rock lobster.</span>
<span class="attribution"><span class="source">Eva Plaganyi-Lloyd</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>CSIRO researchers have worked in the strait for more than three decades to help local people sustain their traditional way of life and conserve the marine environment for future generations. </p>
<p>This is no easy feat, considering the resources are also shared with an Australian non-Islander sector and traditional owners from Papua New Guinea.</p>
<p>The region’s wild marine fisheries have been thriving thanks to good management and a strong sense of custodianship by the Islanders. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=897&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=897&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=897&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1127&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1127&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315875/original/file-20200218-10985-u6bfbr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1127&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">CSIRO scientists doing a survey of tropical lobster numbers. These annual surveys are used with fishery data to calculate the season quotas for the fishery.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p><a href="https://pzja.govcms.gov.au/sites/default/files/bdm_harvest_strategy_adopted_nov_2019.pdf">New harvest strategies</a> for fishing lobster and bêche-de-mer (sea cucumbers) were implemented in December 2019. These took years of research and consultation. This included augmenting scientific surveys with information from fishers to work out sustainable catches.</p>
<p>The new strategies followed a disastrous lobster-fishing year in 2018, when our scientific surveys suggested the lobster population was in trouble due to conditions created by extreme El Niño events. The fishery had to be closed two months early, with substantial economic impact. It was nonetheless an example of Torres Strait Islanders putting sustainability before short-term gain. </p>
<h2>No offsets</h2>
<p>Now they have the coronavirus to contend with. </p>
<p>The loss of income from those in the fishing business affects other small businesses and ripples throughout the local community. </p>
<p>Selling to the frozen seafood market is an option, but prices are much lower, and there’s a point at which the time, effort and cost of catching a tropical rock lobster make it uneconomical. Boat fuel, for one thing, is expensive. Sales of frozen seafood to China have also taken a dive. </p>
<p>For some Australian fisheries it’s possible taking fewer fish this season will mean a larger fish population next year. So next year’s catch quotas could be adjusted up without jeopardising the marine population. This could partially offset losses this year. </p>
<p>But that’s not an option for the Torres Strait lobster fishery. That’s because by the time a lobster is big enough to catch, usually in its third year of life, it is also ready to migrate, walking several hundred kilometres to the east of the fishery area. So catching fewer lobsters this year won’t mean they are around to catch next year. It is a unique fishery in this regard.</p>
<h2>Planning sustainable exports</h2>
<p>This impact of the coronavirus on Torres Strait Islanders shows how <a href="https://theconversation.com/vital-signs-a-connected-world-makes-this-coronavirus-scarier-but-also-helps-us-deal-with-it-131662">connected global trade</a> now is. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/high-tech-shortages-loom-as-coronavirus-shutdowns-hit-manufacturers-131646">High-tech shortages loom as coronavirus shutdowns hit manufacturers</a>
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<p>What it also demonstrates is the importance of deliberate and distributed growth in export markets for them to be sustainable. </p>
<p>Heavy dependence on a single market carries a big risk. As things stand, we can expect demand for seafood in China will remain low for some time to come. </p>
<p>This is an opportune time to rethink sustainable export growth strategies.</p><img src="https://counter.theconversation.com/content/131750/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eva Plaganyi receives funding from several sources including CSIRO, AFMA, FRDC. She has been engaged in research on Torres Strait fisheries since 2009. </span></em></p><p class="fine-print"><em><span>Nicole Murphy receives funding from CSIRO, AFMA </span></em></p><p class="fine-print"><em><span>Roy Aijun Deng receives funding from CSIRO, AFMA, FRDC </span></em></p><p class="fine-print"><em><span>Sean Pascoe receives funding from several sources including CSIRO, AFMA and FRDC.</span></em></p><p class="fine-print"><em><span>Trevor Hutton receives funding from CSIRO, AFMA and FRDC </span></em></p>The abrupt downturn in seafood consumption in China is wreaking havoc on the traditional fishers of the Torres Strait and other Australian fishing communitiesÉva Plagányi, Principal Research Scientist, CSIRONicole Murphy, Experimental Scientist, CSIRORoy Aijun Deng, Senior experimental scientist, CSIROSean Pascoe, Fisheries Economist, Oceans and Atmosphere, CSIROTrevor Hutton, Senior Research Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1248452019-10-15T15:24:54Z2019-10-15T15:24:54ZHow tiny creatures are reshaping the very rivers they live in<figure><img src="https://images.theconversation.com/files/296918/original/file-20191014-135495-z439ev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Caddisfly larvae rearrange pebbles on the river bed to build themselves a shelter.</span> <span class="attribution"><span class="source">FJAH / shutterstock</span></span></figcaption></figure><p>What shapes a river? People typically imagine large-scale processes such as storms and floods or human modifications like dams or fortified banks. But the shape of our rivers today is also a result of the cumulative impact of millions of tiny invertebrates, often small enough that most people don’t even notice them.</p>
<p>“Zoogeomorphology” is the study of how animals effect their physical environment, such as by moving sediment or modifying the habitat. The zoogeomorphic effects of larger organisms are easily seen. For example, when a beaver builds a dam it retains water, creating diverse wetlands upstream and sometimes helping to reduce flooding downstream. Fish also alter the river, turning over gravels while feeding and spawning. </p>
<p>The individual impacts of invertebrates are much smaller but, collectively, they can make a big difference. Charles Darwin recognised this as early as 1881 in his snappy-titled “<a href="http://darwin-online.org.uk/content/frameset?itemID=F1357&viewtype=text&pageseq=1">The Formation of Vegetable Mould through the Action of Worms, with Observations on their Habits</a>”, and the same is true in rivers. This army of small engineers is changing river environments, and we are part of a research group that is working out exactly how. </p>
<p>Here are three small creatures we already know are having a big impact:</p>
<h2>1) Crayfish – burrowing banks</h2>
<p>Signal crayfish are freshwater crustaceans, similar in shape to lobsters but only about the size of an iPhone. Signal crayfish were introduced to the UK in the 1970s to be farmed for food. But after a series of escapes, the species is now widespread, with no known methods for eradication. Signal crayfish are having detrimental impacts on the ecology of rivers. They feed largely on aquatic plants and native invertebrates, consequently modifying the species of native fauna and flora present. Furthermore, via competition and spreading crayfish plague, signal crayfish are destroying populations of native white-clawed crayfish. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=528&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=528&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=528&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=663&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=663&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297090/original/file-20191015-98678-11u4saw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=663&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An invasive signal crayfish hiding in its burrow in Leicestershire, England.</span>
<span class="attribution"><span class="source">Harry Sanders</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Signal crayfish are also dramatically changing the river environment. In the UK, they burrow into clay banks, causing bank failure, bringing down buildings and infrastructure. For example, the burrowing into earth dams at Prior Park Landscape Gardens in Bath has necessitated repairs costing <a href="https://www.bbc.co.uk/news/uk-england-somerset-44314534">millions of pounds</a>. Crayfish burrowing also adds <a href="https://doi.org/10.1016/J.SCITOTENV.2016.06.194">vast quantities of clay</a> into the river which clogs gravel-beds and is bad news for fish who like to spawn in gravel.</p>
<h2>2) Mussels – gluing gravels</h2>
<p>Mussels filter the water they live in, removing sediment and organic detritus. Native freshwater mussels are keystone species, facilitating <a href="https://bioone.org/journals/Freshwater-Science/volume-25/issue-3/0887-3593(2006)25%5B691:UMIMAS%5D2.0.CO;2/Unionid-mussels-influence-macroinvertebrate-assemblage-structure-in-streams/10.1899/0887-3593(2006)25%5B691:UMIMAS%5D2.0.CO;2.full">higher populations of other invertebrates</a>. However, invasive mussels are causing problems. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=802&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=802&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=802&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1008&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1008&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297089/original/file-20191015-98670-ezbed2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1008&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Quagga mussels attach themselves to river gravels and each other. River Wraysbury, England.</span>
<span class="attribution"><span class="source">Harry Sanders</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Zebra mussels, originally from Russia and the Ukraine, are prolific breeders and have now spread across Europe and into the Great Lakes of the US and Canada, where they are blocking pipes and costing American water and electric companies an estimated $17.8m each year. </p>
<p>The zebra mussel was first found in the UK in 1825 but has seen a recent rapid expansion, and lately its larger cousin, the quagga mussel has arrived. These mussels attach themselves to river gravels, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2427.2010.02532.x">native mussels</a>, and each other, creating a dense mesh of mussels. This effectively solidifies the river bed, reducing the quality of the habitat for other animals.</p>
<h2>3) Caddisfly – sticking stones</h2>
<p>Caddisflies are an incredibly diverse group of aquatic insects, with nearly 200 species in the UK alone. Their larvae produce silk, similar to spiders, except it is sticky underwater, and many species use it to construct silk nets much like spider webs. Caddisflies string these nets between stones in order to catch particles of food moving down the river. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297092/original/file-20191015-98632-1ral7gd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Caddisfly nets.</span>
<span class="attribution"><span class="source">Matthew Johnson</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These nets also act to <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0209087">tie river gravels together</a>. This results in more stable patches of gravel, reducing erosion and possibly providing a safe refuge for other invertebrates in floods. Caddisfly larvae are smaller than a thumbnail, however they are often found in extremely high numbers with many thousands of individuals per square metre of river bed. This abundance, coupled with their extraordinary use of silk, means they can affect the geomorphology of rivers.</p>
<p>In addition to building nets, many species of caddisfly larvae construct “cases” to protect them from predator fish, both as larvae and when pupating (transforming into flies). To build these cases, larvae use silk to stick together everything from gravel to very fine sand and bits of plants. By transporting this sand around the river bed, tiny <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/esp.4670">caddisflies may impact much larger physical processes</a>, such as the transport of sand downstream.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/297196/original/file-20191015-98670-mgc088.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Caddisfly ‘cases’ on algae covered stones in a laboratory flume (indoor river) at Loughborough University River Science laboratory.</span>
<span class="attribution"><span class="source">Richard Mason</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Aquatic invertebrates, such as the three considered above, may be small but they can shape the landscape around them. We need to better understand these zoogeomorphic effects because without them we cannot predict how rivers will change over time, including in response to climate change. </p>
<p>In the case of invasive creatures such as signal crayfish and zebra mussels, it is important to prevent their spread not only to protect native species, but to prevent the invaders changing their habitat for the worse. However, native species may be key to the restoration of rivers.</p><img src="https://counter.theconversation.com/content/124845/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Mason receives funding from the Natural Environment Research Council (NERC) to conduct his PhD research on caddisfly.</span></em></p><p class="fine-print"><em><span>Harry Sanders does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Rivers are shaped by storms, floods, humans and… aquatic invertebrates.Richard Mason, PhD Researcher, River Zoogeomorphology, Loughborough UniversityHarry Sanders, PhD Researcher, Zoogeomorphology, Loughborough UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1184522019-06-13T03:07:36Z2019-06-13T03:07:36ZA giant species of trilobite inhabited Australian waters half a billion years ago<figure><img src="https://images.theconversation.com/files/278774/original/file-20190611-52767-o6xd9p.jpg?ixlib=rb-1.1.0&rect=269%2C128%2C1515%2C877&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A fossil of the giant new trilobite species _Redlichia rex_.
</span> <span class="attribution"><span class="source">James Holmes</span>, <span class="license">Author provided</span></span></figcaption></figure><p>At up to 30cm long and armed with spines for crushing and shredding food, we’ve identified a previously unknown creature that would have been a giant among its neighbours in the waters off modern-day South Australia.</p>
<p>The newly described fossil of a trilobite – known as <em>Redlichia rex</em> – is detailed in a <a href="https://www.tandfonline.com/doi/full/10.1080/14772019.2019.1605411" title="The trilobite Redlichia from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia: systematics, ontogeny and soft-part anatomy">paper out this week in the Journal of Systematic Palaeontology</a>.</p>
<p>There is even evidence this monster of the ancient sea could have been a cannibal, feeding on its own kind.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-are-humans-going-to-evolve-again-116990">Curious Kids: are humans going to evolve again?</a>
</strong>
</em>
</p>
<hr>
<p>Trilobites are related to modern-day <a href="https://australianmuseum.net.au/learn/animals/crustaceans/">crustaceans</a> (such as crabs and lobsters) and insects, and are some of the oldest animals to appear in the fossil record. </p>
<p>Because of their abundance, trilobites are considered a model group for understanding the <a href="https://theconversation.com/life-quickly-finds-a-way-the-surprisingly-swift-end-to-evolutions-big-bang-110984">Cambrian explosion</a> – the sudden appearance about 540 million years ago of almost all major animal groups on Earth.</p>
<p>Trilobites first appeared around 520 million years ago and lasted for about 270 million years. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=563&fit=crop&dpr=1 600w, https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=563&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=563&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=708&fit=crop&dpr=1 754w, https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=708&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/278452/original/file-20190607-97989-vcn3y3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=708&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An illustration of the Cambrian seafloor with the trilobite <em>Redlichia rex</em> in the foreground.</span>
<span class="attribution"><span class="source">Katrina Kenny</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Exceptional fossil deposits</h2>
<p>Our most important understanding of life around the time of the Cambrian explosion comes from a series of rare, exceptional fossil deposits called <em>Konservat-Lagerstätten</em> (German for “conservation storage-place”).</p>
<p>These deposits preserve not only the hard parts of organisms such as shells, but also the soft parts such as eyes, muscles and guts. The most famous of these is the <a href="https://burgess-shale.rom.on.ca/en/">Burgess Shale</a> from Canada, although a number of other similar deposits have been discovered in places such as China and Greenland. </p>
<p>Australia also boasts one of these deposits – the only one in the Southern Hemisphere. It is called the Emu Bay Shale and is found on Kangaroo Island in South Australia.</p>
<p>The most common fossils within the Emu Bay Shale are <a href="https://australianmuseum.net.au/learn/australia-over-time/fossils/what-are-trilobites/">trilobites</a>.</p>
<h2>The latest find</h2>
<p>In our <a href="https://www.tandfonline.com/doi/full/10.1080/14772019.2019.1605411" title="The trilobite Redlichia from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia: systematics, ontogeny and soft-part anatomy">study</a>, we describe a very large new trilobite from the Emu Bay Shale. It’s one of the largest trilobites known from the Cambrian Period.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=417&fit=crop&dpr=1 754w, https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=417&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/279262/original/file-20190613-32321-10alvvm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=417&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A large specimen of the newly described trilobite <em>Redlicha rex</em> from the Emu Bay Shale compared to a 20c coin.</span>
<span class="attribution"><span class="source">James Holmes/University of Adelaide</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Due to its exceptional size and armament, we decided <em>Redlichia rex</em> would be an appropriate name. This is reminiscent of the name <em>Tyrannosaurus rex</em> – <em>rex</em> means “king” in Latin. The <em>Redlichia</em> part of the name is the genus (the same as <em>Homo</em> in <em>Homo sapiens</em>), originally named in 1902 after palaeontologist Karl Redlich.</p>
<p>Because the Emu Bay Shale preserves the soft parts of organisms, we find the appendages (or legs) of trilobites preserved as well as the hard shell. These soft parts are extremely rare – complete appendages are known for only six of the more than <a href="https://www.trilobites.info/">20,000</a> described species.</p>
<p>What is even more special about the Emu Bay Shale examples is that because <em>Redlichia rex</em> was so big, the appendages are also very large, making them easier to look at in detail.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/279272/original/file-20190613-32321-74pvwf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A graphic reconstruction of the <em>Redlichia rex</em> appendage used for shredding and crushing prey.</span>
<span class="attribution"><span class="source">Katrina Kenny</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The most important feature of these is an enlarged inner side of the base of each pair of legs, which was covered in short, robust spines and worked as a nutcracker. </p>
<h2>Carnivores of the sea</h2>
<p>Unlike those of other trilobites, the morphology of the spines suggests they may have been adapted to crushing shells of other Cambrian animals. If this were the case, the most likely food <em>Redlichia rex</em> would have been eating was other trilobites. </p>
<p>In the Emu Bay Shale, we also find what are called coprolites, or fossilised poo. In these we find pieces of crushed-up trilobite.</p>
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<span class="caption">Crushed-up pieces of trilobite were found in the coprolites, the fossilised poo.</span>
<span class="attribution"><span class="source">James Holmes</span>, <span class="license">Author provided</span></span>
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<p>It was originally thought poo fossils such as these were produced by the giant Cambrian predator <a href="https://museumsvictoria.com.au/website/melbournemuseum/discoverycentre/600-million-years/videos/understanding-anomalocaris/index.html"><em>Anomalocaris</em></a> – a metre-long beast with two strange claws in the head and a circular, vampire-toothed mouth. But it now seems likely that <em>Redlichia rex</em> produced some of these.</p>
<p>Consistent with this idea, some specimens of <em>Redlichia rex</em> show injuries resulting from attack. These may also be from <em>Anomalocaris</em>, although it is possible that <em>Redlichia rex</em> indulged in cannibalism, or took part in territorial battles (as is seen in modern lobsters).</p>
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Read more:
<a href="https://theconversation.com/life-quickly-finds-a-way-the-surprisingly-swift-end-to-evolutions-big-bang-110984">Life quickly finds a way: the surprisingly swift end to evolution's big bang</a>
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<p>Once animals began to eat each other, the selective pressure to adapt methods to prevent being eaten would have been very high. This is almost certainly the reason why hard shells evolved in the Cambrian – for protection against predation.</p>
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<figcaption><span class="caption">Lobsters caught battling it out today.</span></figcaption>
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<p>The result would have been an evolutionary arms race between predators and prey, with each developing more efficient ways of defence and attack, such as the development of shell-crushing abilities in certain animals.</p>
<p>The formidable appendages of <em>Redlichia rex</em> are probably a result of this, and this giant trilobite was likely a source of terror for small creatures on the Cambrian seafloor.</p><img src="https://counter.theconversation.com/content/118452/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James D. Holmes receives funding from the Australian Government via an RTS PhD scholarship and from the University of Adelaide.</span></em></p><p class="fine-print"><em><span>Diego C. García-Bellido receives funding from Australian Research Council, National Geographic Society and Spanish Ministry of Science. </span></em></p><p class="fine-print"><em><span>John Paterson receives funding from the Australian Research Council and National Geographic. </span></em></p>There is evidence to show this monster of the ancient sea was a cannibal, feeding on its own kind.James D. Holmes, Palaeontology PhD student, University of AdelaideDiego C. García-Bellido, Associate Professor, University of AdelaideJohn Paterson, Professor of Earth Sciences, University of New EnglandLicensed as Creative Commons – attribution, no derivatives.