tag:theconversation.com,2011:/au/topics/marine-biology-5939/articles
Marine biology – The Conversation
2024-03-28T12:47:33Z
tag:theconversation.com,2011:article/224480
2024-03-28T12:47:33Z
2024-03-28T12:47:33Z
As climate change and pollution imperil coral reefs, scientists are deep-freezing corals to repopulate future oceans
<figure><img src="https://images.theconversation.com/files/584286/original/file-20240326-20-w2d62d.jpg?ixlib=rb-1.1.0&rect=29%2C0%2C3964%2C2994&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Healthy corals like these on Australia's Lady Elliot Reef could disappear by the 2030s if climate change is not curbed. </span> <span class="attribution"><span class="source">Rebecca Spindler</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Coral reefs are some of the <a href="https://sanctuaries.noaa.gov/education/teachers/coral-reef/background.html">oldest, most diverse ecosystems</a> on Earth, and among the most valuable. They nurture <a href="https://www.noaa.gov/education/resource-collections/marine-life/coral-reef-ecosystems">25% of all ocean life</a>, <a href="https://oceanservice.noaa.gov/facts/coral_protect.html">protect coasts from storms</a> and add <a href="https://oceanservice.noaa.gov/facts/coral_economy.html">billions of dollars yearly</a> to the global economy through their influences on fisheries, new pharmaceuticals, tourism and recreation. </p>
<p>Today, the world’s coral reefs are degrading at <a href="https://oceanservice.noaa.gov/education/tutorial_corals/coral09_humanthreats.html">unprecedented rates</a> due to pollution, overfishing and <a href="https://doi.org/10.1016/j.biocon.2017.04.024">destructive forestry</a> and <a href="https://doi.org/10.1016/j.scitotenv.2019.07.139">mining practices</a> on land. Climate change driven by human activities is <a href="https://www.ipcc.ch/report/ar6/wg1/downloads/factsheets/IPCC_AR6_WGI_Regional_Fact_Sheet_Ocean.pdf">warming and acidifying the ocean</a>, producing a <a href="https://theconversation.com/corals-are-starting-to-bleach-as-global-ocean-temperatures-hit-record-highs-209770">reef crisis</a> that could cause most corals to go extinct <a href="https://doi.org/10.1029/2021EF002608">within a few generations</a>. </p>
<p>I am a <a href="https://www.researchgate.net/scientific-contributions/Mary-Hagedorn-2111114778">marine biologist</a> at the Smithsonian’s <a href="https://nationalzoo.si.edu/conservation/about-scbi">National Zoo and Conservation Biology Institute</a>. For 17 years, I have worked with colleagues to create a global science program called the <a href="https://global.si.edu/projects/reef-recovery-initiative">Reef Recovery Initiative</a> that aims to help save coral reefs by using the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/cryopreservation">science of cryopreservation</a>. </p>
<p>This novel approach involves storing and cooling coral sperm and larvae, or <a href="https://wi.mit.edu/news/immortality-germ-cells">germ cells</a>, at very low temperatures and holding them in <a href="https://naturalhistorymuseum.blog/2022/07/26/biodiversity-biobanks-an-invaluable-resource-for-the-future/">government biorepositories</a>.</p>
<p>These repositories are an important hedge against extinction for corals. Managed effectively, they can help offset threats to the Earth’s reefs on a global scale. These frozen assets can be used today, 10 years or even 100 years from now to help reseed the oceans and restore living reefs.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/3Bko2bhQgG0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Smithsonian scientists use cryopreserved coral sperm to increase the genetic diversity of elkhorn coral.</span></figcaption>
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<h2>Safely frozen alive</h2>
<p>Cryopreservation is a process for freezing biological material while maintaining its viability. It involves introducing sugarlike substances, called cryoprotectants, into cells to help prevent lethal ice formation during the freezing phase. If done properly, the cells remain frozen and alive in liquid nitrogen, unchanged, for many years. </p>
<p>Many organisms survive through cold winters in nature by becoming naturally cryopreserved as temperatures in their habitats drop below freezing, Two examples that are common across North America are <a href="https://new.nsf.gov/news/how-do-microscopic-creatures-called-tardigrades">tardigrades – microscopic animals that live in mosses and lichens</a> – and <a href="https://doi.org/10.1016/j.cbpb.2022.110747">wood frogs</a>. </p>
<p>Today, coral cryopreservation techniques rely largely on <a href="https://doi.org/10.1371/journal.pone.0033354">freezing sperm</a> <a href="https://doi.org/10.1038/s41598-018-34035-0">and larvae</a>. Since 2007, I have trained many colleagues in coral cryopreservation and worked with them to successfully preserve coral sperm. Today we have sperm from over 50 species of corals <a href="https://nationalzoo.si.edu/center-for-species-survival/coral-species-cryopreserved-global-collaborators">preserved in biorepositories worldwide</a>. </p>
<p>We have used this cryopreserved sperm to produce new coral across the Caribbean via a selective breeding process called <a href="https://doi.org/10.1073/pnas.2110559118">assisted gene flow</a>. The goal was to use cryopreserved sperm and interbreed corals that would not necessarily have encountered each other – a type of long-distance matchmaking. </p>
<p>Genetic diversity is maintained by combining as many different parents as possible to produce new sexually produced offspring. Since corals are cemented to the seabed, when population numbers in their area decline, new individuals can be introduced via cryopreservation. The hope is that these new genetic combinations might have an adaptation that will help coral survive changes in future warming oceans.</p>
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<a href="https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two coral heads, one bleached white, the other still its natural brown color." src="https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584774/original/file-20240327-20-jmcyqb.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">Corals in Kaneohe Bay, Hawaii during 2014 and 2015 warming events in which over 80% of corals were affected. Some species and individuals, like the coral at left, were resistant to warming.</span>
<span class="attribution"><span class="source">Claire Lager, Smithsonian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
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<p>These assisted gene flow studies produced 600 new genetic-assorted individuals of the threatened elkhorn coral <em>Acropora palmata</em>. As of early 2024, there are only about 150 elkhorn individuals left in the wild in the Florida population. If given the chance, these selectively bred corals held in captivity could significantly increase the wild elkhorn gene pool. </p>
<p>Preserving sperm cells and larvae is an important hedge against the loss of biodiversity and species extinctions. But we can only collect this material during <a href="https://www.youtube.com/watch?v=eO_2JJynlOA">fleeting spawning events</a> when corals release egg and sperm into the water. </p>
<p>These episodes occur over just a few days a year – a small time window that poses logistical challenges for researchers and conservationists, and limits the speed at which we can successfully cryo-bank coral species. </p>
<p>To complicate matters further, warming oceans and increasingly frequent marine heat waves can biologically stress corals. This can make their reproductive material too weak to withstand the rigors of being cryopreserved and thawed. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582584/original/file-20240318-24-kam7rc.png?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"></a>
<figcaption>
<span class="caption">An elkhorn coral produced through assisted gene flow, showing vigorous growth and development.</span>
<span class="attribution"><span class="source">Cody Engelsma</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
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<h2>Scaling up the rescue</h2>
<p>To collect coral material faster, we are developing a cryopreservation process for whole coral fragments, using a method called <a href="https://doi.org/10.1038/s41467-023-40500-w">isochoric vitrification</a>. This technique is still developing. However, if fully successful, it will preserve whole coral fragments without causing ice to form in their tissues, thus producing viable fragments after they’ve thawed that thrive and can be placed back out on the reef. </p>
<p>To do this, we dehydrate the fragment by exposing it to a viscous cryoprotectant cocktail. Then we place it into a small aluminum cylinder and immerse the cylinder in liquid nitrogen, which has a temperature of <a href="https://www.sciencedirect.com/topics/chemical-engineering/liquid-nitrogen">minus 320 degrees Fahrenheit (minus 196 Celsius)</a>. </p>
<p>This process freezes the cylinder’s contents so fast that the cryoprotectant forms a clear glass instead of allowing ice crystals to develop. When we want to thaw the fragments, we place them into a warm water bath for a few minutes, then rehydrate them in seawater. </p>
<p>Using this method, we can collect and cryopreserve coral fragments year-round, since we don’t have to wait and watch for fleeting spawning events. This approach greatly accelerates our conservation efforts. </p>
<p>Protecting as many species as possible will require expanding and sharing our science to create robust cryopreserved-and-thawed coral material through multiple methods. My colleagues and I want the technology to be easy, fast and cheap so any professional can replicate our process and help us preserve corals across the globe. </p>
<p>We have created a video-based coral cryo-training program that includes directions for <a href="https://nationalzoo.si.edu/center-for-species-survival/coral-cryopreservation-training-course">building simple, 3D-printed cryo-freezers</a>, and have collaborated with engineers to develop new methods that now allow coral larvae to be frozen by the hundreds on <a href="https://doi.org/10.1002/advs.202303317">simple, inexpensive metal meshes</a>. These new tools will make it possible for labs around the world to significantly accelerate coral collection around the globe within the next five years.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/_5DooxgwEiw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Without coral reefs, the world would lose a valuable source of food, coastal protection, medicines and income – and some of the world’s most unique and beautiful ecosystems.</span></figcaption>
</figure>
<h2>Safeguarding the future</h2>
<p>Recent climate models estimate that if greenhouse gas emissions continue unabated, 95% or more of the world’s corals <a href="https://doi.org/10.1371/journal.pclm.0000004">could die by the mid-2030s</a>. This leaves precious little time to conserve the biodiversity and genetic diversity of reefs.</p>
<p>One approach, which is already under way, is bringing all coral species into human care. The Smithsonian is part of the <a href="https://nationalzoo.si.edu/center-for-species-survival/coral-biobank-alliance">Coral Biobank Alliance</a>, an international collaboration to conserve corals by collecting live colonies, skeletons and genetic samples and using the best scientific practices to help rebuild reefs. </p>
<p>To date, over 200 coral species, out of some 1,000 known hard coral species, and thousands of colonies are under human care in institutions around the world, including organizations connected with the U.S. and European arms of the <a href="https://www.aza.org/">Association of Zoos and Aquariums</a>. Although these are clones of colonies from the wild, these individuals could be put into coral breeding systems that could be used for later cryopreservation of their genetically-assorted larvae. Alternatively, their larvae could be used for reef restoration projects. </p>
<p>Until climate change is slowed and reversed, reefs will continue to degrade. Ensuring a better future for coral reefs will require building up coral biorepositories, establishing on-land nurseries to hold coral colonies and develop new larval settlers, and training new cryo-professionals. </p>
<p>For decades, zoos have used <a href="https://www.cnn.com/2020/09/17/world/captive-breeding-species-cte-scn-spc-intl/index.html">captive breeding and reintroduction</a> to protect animals species that have fallen to critically low levels. Similarly, I believe our novel solutions can create hope and help save coral reefs to reseed our oceans today and long into the future.</p><img src="https://counter.theconversation.com/content/224480/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mary Hagedorn receives funding from Revive & Restore; Paul M. Angell Family Foundation; Volgenau Foundation; CORDAP Foundation; Zegar Family Foundation; Oceankind; Mastriani Family; De Witt Family; Anela Kolohe Foundation; Cedar Hill Foundation; Sidney E. Frank Foundation; Scintilla Foundation; and the Smithsonian Women’s Committee.
She is affiliated with Smithsonian National Zoo and Conservation Biology Institute and the Hawaii Institute of Marine Biology. </span></em></p>
Just as the world’s zoos breed critically endangered animals in captivity to repopulate the wild, scientists are building a global effort to freeze corals for reef restoration.
Mary Hagedorn, Research Scientist, Smithsonian Institution
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/224682
2024-03-20T22:41:06Z
2024-03-20T22:41:06Z
How do halibut migrate? Clues are in their ear bones
<figure><img src="https://images.theconversation.com/files/578657/original/file-20240220-18-5yndy5.jpg?ixlib=rb-1.1.0&rect=24%2C18%2C3953%2C2999&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The habitats used throughout the halibut's life and the movements between them are difficult to characterize.</span> <span class="attribution"><span class="source">(Charlotte Gauthier)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>Rising temperatures, changes in major currents, <a href="https://theconversation.com/why-the-st-lawrence-estuary-is-running-out-of-breath-184626">oxygen depletion at great depths</a>: the Gulf of St. Lawrence has undergone major changes in its environmental conditions in recent decades. That has put many species in danger and, as a consequence, made them more sensitive to the effects of fishing.</p>
<p>However, these changes are benefiting other species such as Atlantic halibut, which is beating records for its abundance and is presently seeing the highest stock in the Gulf of St. Lawrence in <a href="https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/41206708.pdf">the last 60 years</a>.</p>
<p>As a biology researcher, I’d like to shed some light on some of the mysteries that still surround this unusual species.</p>
<hr>
<figure class="align-right ">
<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>
<hr>
<h2>Atlantic halibut: champion of the Gulf of St. Lawrence</h2>
<p>Atlantic halibut is a flatfish that lives at the bottom of the estuary and gulf of the St. Lawrence. It is prized for its fine, firm white flesh, which is highly appreciated by consumers.</p>
<p>Halibut can grow to impressive sizes of <a href="https://www.tandfonline.com/doi/full/10.1080/23308249.2021.1948502">more than two metres</a>. Because of the quality of its flesh and its popularity on dinner plates, it is currently the most commercially valuable fish in the Gulf of St. Lawrence.</p>
<p>But this has not always been the case. In the 1950s, the adult, harvestable portion of halibut populations, known as the stock, <a href="https://academic.oup.com/icesjms/article/73/4/1104/2458915?login=false">suffered a major decline due to overfishing</a>.</p>
<p>If we want to continue to exploit this resource over the long term, we must not repeat the same mistakes we made in the past. To avoid these mistakes, it is vital to have a good understanding of the life cycle of halibut and the effects that fishing can have on the stock. So far, this has not been done to the fullest.</p>
<h2>The challenges for sustainable fishing</h2>
<p>The basic biology of Atlantic halibut is fairly well known. However, both the habitats they use throughout their lives and their movement between these places are more difficult to characterize.</p>
<p><a href="https://academic.oup.com/icesjms/article/77/7-8/2890/5923787?login=false">Recent studies</a> have placed satellite tags on halibut to record data on the depth and temperature of the water in which they are found, making it possible to accurately calculate their movement. By using this method, the researchers were able to identify the trajectories of adult halibut over a one-year period and discover that they reproduce in winter in the deep channels of the Gulf.</p>
<p>In the halibut’s different annual trajectories, the researchers observed that, in summer, some remain in the deep channels while others migrate to shallower areas.</p>
<p>Even with this new information, a number of questions remain, specifically about the youngest life stages, which are caught only anecdotally in the Gulf. Satellite tags also provide accurate information, but only over a one-year period, which doesn’t tell the whole story for a fish that can live up to 50 years.</p>
<p>With this in mind, the use of a new tool to study the entire life of fish becomes highly relevant.</p>
<h2>Ear bones to the rescue</h2>
<p>All bony fish have small calcareous structures in their inner ear called otoliths, or ear bones, which perform balance and hearing functions.</p>
<p>Otoliths develop at the very beginning of a fish’s life and grow at the same rate as the fish. Otoliths form annual growth rings that are comparable to those visible in tree trunks.</p>
<p>To grow, otoliths accumulate chemical elements that are found in the environment in which the fish swim. So, when the fish moves, the chemical elements accumulated in the otoliths will be different from one place to another. Each location is characterized by a unique combination of different concentrations of chemical elements. This is known as an elemental fingerprint. Identifying these fingerprints can provide us with crucial information about the movement of fish in different places throughout their lives.</p>
<p>I used this method of characterizing the chemical elements in otoliths to study the migratory patterns of Atlantic halibut in the Gulf of St. Lawrence.</p>
<h2>A wide range of migratory strategies</h2>
<p>To find out what concentrations of a chemical element correspond to the place where the fish was caught, we use the fingerprint of the otolith margin, i.e. the material at the end of the outermost ring of the otolith, which was accumulated last.</p>
<p>The concentrations of the elements found there are considered to be characteristic of the place where the fish was caught. By analyzing the margins of nearly 200 halibut otoliths from all over the Gulf, I was able to distinguish two basic fingerprints: one representative of surface waters (less than 100 metres deep) and one characteristic of deeper waters (more than 100 metres deep).</p>
<p>Once these fingerprints had been identified, I observed the concentration of chemical elements throughout the life of the fish so that I could associate each moment of life with either the surface water fingerprint or the deep-water fingerprint.</p>
<p>By separating the life of each individual into time spent in surface and deep waters, I was able to identify recurring patterns and group them into three different migratory strategies: residents, annual migrants and irregular migrants.</p>
<p>In this way, I was able to observe that halibut caught in the southern part of the Gulf were mainly annual migrants, and therefore undertake migrations between deep and shallow waters every year. However, in the northern part of the Gulf the majority are residents. Residents are fish that may have migrated early in their lives, but have settled permanently in deep waters before reaching maturity. Irregular migrants, on the other hand, show migrations on a more sporadic frequency, and are found in similar proportions throughout the study area.</p>
<h2>On the right track to optimal management</h2>
<p>My study is the first to offer a global view of the movements made by halibut over their entire lifetime.</p>
<p>This new information provides a better understanding of the structure of the stock and the diversity of migratory strategies that can be found within it.</p>
<p>Given that these strategies are distributed differently in different areas of the Gulf, we can ensure that we do not disproportionately target halibut using the same migratory strategy and avoid overfishing a single component of the stock.</p>
<p>In this way, it is possible to conserve this diversity, which helps the stock’s resilience in the face of the various changes that can occur.</p><img src="https://counter.theconversation.com/content/224682/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charlotte Gauthier has received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fondation de l'Université du Québec à Chicoutimi.
</span></em></p>
Atlantic halibut are making a strong comeback in the Gulf of St. Lawrence. But how do we know where the fish move throughout their lives?
Charlotte Gauthier, Étudiante au doctorat, Université du Québec à Chicoutimi (UQAC)
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/225257
2024-03-13T00:02:52Z
2024-03-13T00:02:52Z
Surviving fishing gear entanglement isn’t enough for endangered right whales – females still don’t breed afterward
<figure><img src="https://images.theconversation.com/files/581023/original/file-20240311-30-7n1k5g.jpg?ixlib=rb-1.1.0&rect=15%2C7%2C5240%2C3936&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Endangered North Atlantic right whale Snow Cone, entangled in fishing rope, with her newborn calf off Georgia in 2021.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/WhaleEntanglement/e4dd953df8dc4ff8a1df41f310d9abda/photo">Georgia Department of Natural Resources/NOAA Permit #21731, via AP</a></span></figcaption></figure><p>It sounds like a crime show episode at sea: In late January 2024, federal regulators learned that a dead female North Atlantic right whale had been sighted near Martha’s Vineyard, Massachusetts. The whale was towed to shore, where more than 20 U.S. and Canadian scientists converged to perform a <a href="https://www.acvp.org/page/Necropsy">necropsy</a>, or animal autopsy. </p>
<p>On Feb. 14, the U.S. National Oceanic and Atmospheric Administration announced that the whale was #5120 in a <a href="https://rwcatalog.neaq.org/#/">catalog that tracks individual right whales</a>. Further, the agency said, rope that had been deeply embedded in the whale’s tail had likely come from <a href="https://www.fisheries.noaa.gov/national/endangered-species-conservation/north-atlantic-right-whale-updates">lobster fishing gear in Maine</a>. </p>
<p>Entanglement in fishing gear is a deadly threat to these <a href="https://www.iucnredlist.org/species/41712/178589687">critically endangered animals</a>. Scientists estimate that before commercial whaling scaled up in the 18th and 19th centuries, there may have been as many as <a href="https://doi.org/10.1111/cobi.12664">10,000 North Atlantic right whales</a>. Today, fewer than 360 individuals remain. <a href="http://dx.doi.org/10.3354/meps09923">Almost 90% of them</a> have been entangled at least once. </p>
<p>When whales become entangled in fishing gear, they use extra energy dragging it as they swim. If the rope is caught around their mouths, they may struggle to feed and slowly starve. Ropes wrapped around whales’ bodies, flippers or tails can cut into the animals’ skin and become <a href="https://theconversation.com/high-tech-fishing-gear-could-help-save-critically-endangered-right-whales-115974">deeply embedded in their flesh</a>, as happened to whale #5120. This can cause infections, chronic emaciation and damage to whales’ blubber, muscle, bone and <a href="https://www.britannica.com/animal/baleen-whale">baleen – the bristly structures in their mouths</a> that they use to filter prey from the water.</p>
<p>North Atlantic right whales are legally protected, both internationally and in U.S. waters, including policies that seek to reduce deaths or serious injuries resulting from entanglements. However, even when entanglement does not kill a whale, it can affect individuals’ ability to reproduce, which is critically important for a species with such low numbers. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ylQ5q7Ivs2o?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Rescuers successfully remove more than 450 feet (137 meters) of rope and a 135-pound (60-kilogram) trap from an entangled North Atlantic right whale at sea.</span></figcaption>
</figure>
<p>In a newly published study, we show that even entanglements scientists classify as minor have <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2024.0314">devastating impacts on female right whales</a> and that, surprisingly, potential mothers who suffer “minor” entanglements have the lowest chance of starting to breed. As researchers with expertise in <a href="https://scholar.google.com.au/citations?user=8zoJjzcAAAAJ&hl=en">marine</a> <a href="https://scholar.google.com/citations?user=8isVxjsAAAAJ&hl=en">biology</a>, <a href="https://scholar.google.com.au/citations?user=CDxPUIEAAAAJ&hl=en">ecology</a> and <a href="https://scholar.google.com/citations?user=P9JQOi8AAAAJ&hl=en">statistics</a>, we believe our findings underline the urgent need for ropeless fishing gear that can reduce threats to the survival of this species.</p>
<h2>Smaller females are having fewer young</h2>
<p>Understanding reproductive patterns is essential for supporting species that are critically endangered. North Atlantic right whales historically started breeding by around 9 years of age and gave birth to a single calf every <a href="https://doi.org/10.3389/fmars.2018.00530">three to four years</a> thereafter for several decades. </p>
<p>Today, however, many females have yet to reproduce at all. Moreover, those that have successfully produced calves now don’t produce another calf for <a href="https://www.narwc.org/uploads/1/1/6/6/116623219/2022reportcardfinal.pdf">more than seven years on average</a>. </p>
<p>As we showed in a 2022 study, after an encouraging North Atlantic right whale population recovery from the 1970s through the early 2000s, the number of reproductively mature female right whales <a href="https://doi.org/10.3389/fmars.2022.994481">declined from 2014 onward</a>. By 2018 there were only about 73 breeding females left, representing roughly half of all females and a sixth of the entire species.</p>
<p>Other research has shown that <a href="https://doi.org/10.3354/meps13299">poor health and physical condition</a> are making it harder for these females to even start breeding. Since the early 1980s, North Atlantic right whales have literally shrunk: Adults have <a href="https://doi.org/10.1016/j.cub.2021.04.067">shorter bodies</a> than they did several decades ago. This trend is associated with entanglements in fishing gear. As is true for all mammals, decreasing female body size <a href="https://doi.org/10.1098/rsos.240050">reduces the likelihood of reproducing</a>. Smaller whales have fewer calves.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic showing North Atlantic right whale population trends" src="https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581026/original/file-20240311-22-t5wyed.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"></a>
<figcaption>
<span class="caption">North Atlantic right whales have been listed as endangered since 1970. Approximately 360 individuals remain, including around 70 reproductively active females.</span>
<span class="attribution"><a class="source" href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale">NOAA Fisheries</a></span>
</figcaption>
</figure>
<p>Low calving rates are a <a href="https://www.fisheries.noaa.gov/feature-story/flying-high-save-north-atlantic-right-whales">significant factor in North Atlantic right whales’ decline</a>, so it is important to understand what causes them. Many organizations are involved in <a href="https://whalemap.org/">tracking North Atlantic right whales</a>, including <a href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale/science">government agencies</a>, <a href="https://www.neaq.org/animal/right-whales/">aquariums</a> and <a href="https://coastalstudies.org/right-whale-research/population-monitoring/">conservation groups</a>. Photos taken from the air enable researchers to identify individuals and so monitor whale population trends, births and deaths, ocean habitat use patterns, health and rates of scarring from entanglements and collisions with ships.</p>
<p>Our new study found that female right whales who have experienced even a minor entanglement before reaching sexual maturity may not ever start to breed. Even females who have previously reproduced are less likely to breed again following an entanglement event.</p>
<p>We determined this by using a mathematical model to incorporate information on the identity of individual whales, derived from photographs of <a href="https://www.neaq.org/conservation-and-research/anderson-cabot-center-for-ocean-life/identifying-right-whales/">natural markings known as callosities</a> on the whales’ heads. By identifying and photographing whales repeatedly over time, scientists can estimate different stages of their life, such as when females give birth. </p>
<h2>Weakness of current regulations</h2>
<p>Researchers categorize the severity of injuries that result from entanglements as <a href="https://doi.org/10.1111/cobi.12590">minor, moderate or severe</a>. The scientists who manage the right whale catalog classify scars or injuries on the skin as minor if they are smaller than 0.8 inches (2 centimeters) without entering the blubber. If they are larger and enter the blubber, they are classified as moderate. Injuries that extend deep into the muscle or bone are categorized as severe.</p>
<p>Our research makes it clear that such value-laden terms are potentially misleading because even minor entanglements can threaten whales’ successful reproduction.</p>
<p>Multiple laws ostensibly protect North Atlantic right whales, including the U.S. <a href="https://www.fisheries.noaa.gov/topic/laws-policies/endangered-species-act">Endangered Species Act</a> and <a href="https://www.fisheries.noaa.gov/topic/laws-policies/marine-mammal-protection-act">Marine Mammal Protection Act</a>, and Canada’s <a href="https://laws-lois.justice.gc.ca/eng/acts/s-15.3/">Species at Risk Act</a>. In our view, these measures do not give enough weight to preventing all types of entanglements, regardless of severity.</p>
<p>Under the Marine Mammal Protection Act, the NOAA develops and implements conservation plans and so-called Take Reduction Plans, which are designed to minimize wildlife deaths and serious injury resulting from commercial fishing gear.</p>
<p>The <a href="https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-mammal-protection/atlantic-large-whale-take-reduction-plan">Atlantic Large Whale Take Reduction Plan</a>, developed in 1997, requires fishers to use <a href="https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-mammal-protection/approved-weak-inserts-atlantic-large-whale-take">weak links</a>, with a maximum breaking strength of 1,700 pounds (771 kilograms), to connect lobster and crab pots to buoys on the surface. These links are intended to break when whales swim into them, so that the whales do not become entangled and weighted down by ropes and traps. </p>
<p>The plan also requires fishers to use heavy ground lines to connect multiple traps or pots. These lines are designed to sink to the bottom rather than floating in the water column. And the plan closes trap fishing areas seasonally when whales are known to be present in those zones. </p>
<figure>
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<figcaption><span class="caption">U.S. and Canadian regulators are considering requiring ‘ropeless’ lobster and crab fishing gear in zones where right whales are present.</span></figcaption>
</figure>
<h2>Coming back from the brink</h2>
<p>Current population estimates suggest that the numbers of North Atlantic right whales <a href="https://www.neaq.org/right-whale-population-estimates-indicate-slowing-decline-scientists-highlight-threats-to-species/">could be stabilizing</a>, meaning that the number of deaths is approximately equal to the number being born. While these estimates seem promising, females need to start and continue producing calves to increase whales’ numbers. </p>
<p>From our work, it is very clear that both lethal and sublethal impacts of entanglements are of grave concern for these whales. As we see it, eliminating entanglement, not mitigating it, is the only way to avoid the extinction of this species. Every entanglement, whatever its severity, is bad news for the whales.</p><img src="https://counter.theconversation.com/content/225257/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Leslie New receives funding from the U.S. Office of Naval Research and the National Science Foundation. She also is a member of the International Whaling Commission Scientific Committee.</span></em></p><p class="fine-print"><em><span>Peter Corkeron consults for Public Employees for Environmental Responsibility on right whale conservation issues. He headed the National Oceanic and Atmospheric Administration's large whale research program for the northeastern US from 2011 to 2019, then led the New England Aquarium's right whale research program through 2022.</span></em></p><p class="fine-print"><em><span>Rob Harcourt receives funding from the Australian Federal Government Department of Climate Change, Environment, Energy and Water for research on right whales. He was a member of the National Marine Mammal Scientific Committee </span></em></p><p class="fine-print"><em><span>Joshua Reed does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Even when female North Atlantic right whales survive entanglement in fishing gear, it may affect their future ability to breed, increasing the pressure on this critically endangered species.
Joshua Reed, Research Associate in Biology, Macquarie University
Leslie New, Assistant Professor of Statistics, Ursinus College
Peter Corkeron, Adjunct Senior Research Fellow, Centre for Planetary Health and Food Security, Griffith University
Rob Harcourt, Professor of Marine Ecology, Macquarie University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/223267
2024-03-08T13:36:46Z
2024-03-08T13:36:46Z
Rare access to hammerhead shark embryos reveals secrets of its unique head development
<figure><img src="https://images.theconversation.com/files/575205/original/file-20240213-26-2257zy.jpeg?ixlib=rb-1.1.0&rect=558%2C0%2C9359%2C6223&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The characteristic hammer-shaped head is just becoming visible in this image of an embryonic bonnethead shark. Scale bar = 1 cm.</span> <span class="attribution"><span class="source">Steven Byrum and Gareth Fraser, Department of Biology, University of Florida</span></span></figcaption></figure><p>Scientists very rarely get access to most sharks, the development of their young or the nursery grounds where they grow. So seeing a <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/sphyrna-tiburo/">hammerhead shark</a> (<em>Sphyrna tiburo</em>) embryo, halfway through its five-month development, is very unusual.</p>
<p>Access to growing embryos is key for <a href="https://scholar.google.com/citations?user=J5qu-2gAAAAJ&hl=en&oi=ao">developmental biologists like me</a> as we try to understand the diversity of animals on Earth. Usually the fishes I study, including other shark species, lay eggs, which allows us to easily watch development in real time.</p>
<p>Hammerhead sharks don’t lay eggs, though. They gestate their pups in utero. A pregnant shark carries up to 16 embryos, each nourished by an umbilical cord, just like human embryos are. Then the mother gives birth to live young, and these babies are self-sufficient with teeth and jaws, ready to survive on their own.</p>
<p>Access to a hammerhead embryo is very rare, which is what makes this image so special.</p>
<h2>Access to a very rare resource</h2>
<p>In order to make this image, my colleagues and I salvaged embryos from adult female sharks that had been caught as part of population surveys off both the Gulf and Atlantic coasts of Florida. Usually these sharks are tagged and released. But a small number die during this process and are then studied for insights about diet, age, growth, reproduction and toxicology. No sharks were sacrificed just for our study. The embryos would have otherwise been wasted when the mothers died.</p>
<p>For this work, <a href="https://scholar.google.com/citations?user=GAE2Hi8AAAAJ&hl=en">Steven Byrum</a>, a graduate student <a href="https://www.fraser-lab.net/">in my lab</a>, was able to <a href="https://doi.org/10.1002/dvdy.658">document the entire set of developmental stages</a> using a total of 177 bonnethead shark embryos.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="composite image of six shark embryos at advancing stages of development" src="https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=849&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=849&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=849&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1067&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1067&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579899/original/file-20240305-20-2yce7q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1067&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Images of embryos of different ages reveal how the sharks develop in utero.</span>
<span class="attribution"><span class="source">Steven Byrum and Gareth Fraser, Department of Biology, University of Florida</span></span>
</figcaption>
</figure>
<p>We were able to assemble a kind of visual growth chart, from the earliest embryos – they look nothing like hammerheads – to the specific point in development when the hammerhead takes shape, through the rest of development before birth. No scientists had ever before charted the development of hammerhead sharks in this way.</p>
<p>This research allows us to study crucial stages in hammerhead development and, importantly, the precise moments – like this one pictured – when the embryo develops the characteristic head shape.</p>
<h2>Adding to what’s known about hammerheads</h2>
<p>Hammerheads are a peculiar group of <a href="https://doi.org/10.1016/j.ympev.2010.01.037">only eight species of sharks</a> that uniquely develop a hammer-shaped head known as a cephalofoil, named for its hydrodynamic design used for <a href="https://doi.org/10.2307/1446449">quick turns and pinning down prey</a>. This particular species is known as the bonnethead because of its relatively small, rounded “hammer.” </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="view from above of grayish fish swimming just above sandy seafloor" src="https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579876/original/file-20240305-28-sk4tsz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&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 grown bonnethead shark has sensory advantages from its hammer-shaped head.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/bonnethead-shark-underwater-bahamas-west-indies-royalty-free-image/200351925-001">Tom Brakefield/Stockbyte via Getty Images</a></span>
</figcaption>
</figure>
<p>Scientists think the wide, flattened head shape with eyes on each side evolved to enhance the animals’ senses. Wide positioning of the eyes allows for an increased field of vision, and wide, expanded nasal capsules provide enhanced olfactory capability.</p>
<p>The hammer-shaped heads are covered with expanded electric detector organs that support the sharks’ “sixth sense.” They can detect even the smallest electrical signals, such as the pulses from a prey fish’s heartbeat, or the Earth’s <a href="https://doi.org/10.1098/rsif.2004.0021">magnetic fields, which they can use to navigate</a> during migration.</p>
<p>Access to these amazing shark pup embryos allows us to compare their development with other regular-headed sharks and ask how and why hammerheads grow these wonderful noggins.</p>
<p>The ocean hides a wealth of weird and wonderful fishes, most of which are inaccessible, and studies of their development are impossible. My lab continues to uncover insights into the evolution of life on Earth thanks to these fortuitous opportunities.</p><img src="https://counter.theconversation.com/content/223267/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gareth J. Fraser receives funding from the National Science Foundation. </span></em></p>
Because hammerhead sharks give birth to live young, studying their embryonic development is much more complicated than harvesting some eggs and watching them develop in real time.
Gareth J. Fraser, Associate Professor of Evolutionary Developmental Biology, University of Florida
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/220629
2024-01-31T13:36:25Z
2024-01-31T13:36:25Z
‘Jaws’ portrayed sharks as monsters 50 years ago, but it also inspired a generation of shark scientists
<figure><img src="https://images.theconversation.com/files/572002/original/file-20240129-17-8m3oe7.jpg?ixlib=rb-1.1.0&rect=37%2C0%2C4952%2C3261&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A paleontologist wears a T-shirt showing _Strophodus rebecae_, a shark species with flat teeth that lived millions of years ago.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/palaeontologist-edwin-cadena-shows-a-t-shirt-with-an-image-news-photo/1241210531">Juan Pablo Pino/AFP via Getty Images</a></span></figcaption></figure><p>Human fear of sharks has deep roots. Written works and art from the ancient world contain references to <a href="https://www.artmajeur.com/en/magazine/5-art-history/sharks-in-art/331942">sharks preying on sailors</a> as early as the eighth century B.C.E. </p>
<p>Relayed back to land, stories about shark encounters have been <a href="https://etc.usf.edu/lit2go/42/moby-dick/747/chapter-66-the-shark-massacre/">embellished and amplified</a>. Together with the fact that from time to time – very rarely – sharks bite humans, people have been primed for centuries to imagine terrifying situations at sea.</p>
<p>In 1974, Peter Benchley’s <a href="https://www.penguinrandomhouse.ca/books/11203/jaws-by-peter-benchley/9780345544148/excerpt">bestselling novel “Jaws</a>” fanned this fear into a wildfire that spread around the world. The book sold more than 5 million copies in the U.S. within a year and was quickly followed by <a href="https://www.imdb.com/title/tt0073195/">Steven Spielberg’s 1975 movie</a>, which became the highest-grossing film in history at that time. Virtually all audiences embraced the idea, depicted vividly in the movie and its sequels, that sharks were malevolent, vindictive creatures that prowled coastal waters seeking to feed on unsuspecting bathers. </p>
<p>But “Jaws” also spawned widespread interest in better understanding sharks. </p>
<p>Previously, shark research had largely been the esoteric domain of a handful of academic specialists. Thanks to interest sparked by “Jaws,” we now know that there are many more kinds of sharks than scientists were aware of in 1974, and that sharks do more interesting things than researchers ever anticipated. Benchley himself became an avid <a href="https://www.latimes.com/archives/la-xpm-2006-feb-13-me-benchley13-story.html">spokesman for shark protection and marine conservation</a>.</p>
<p>In my own 30-year career studying <a href="https://scholar.google.com/citations?user=FKrC4FYAAAAJ&hl=en">sharks and their close relatives, skates and rays</a>, I’ve seen attitudes evolve and interest in understanding sharks expand enormously. Here’s how things have changed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&rect=32%2C8%2C5434%2C3630&q=45&auto=format&w=1000&fit=clip"><img alt="A man stands on the prow of a boat, extending a pole into the water toward a large dark shape." src="https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&rect=32%2C8%2C5434%2C3630&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572000/original/file-20240129-27-l4g7ei.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">Marine biologist Greg Skomal of the Massachusetts Division of Marine Fisheries captures video footage of a white shark off Cape Cod, Oct. 21, 2022.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/dr-greg-skomal-shark-researcher-for-massachusetts-marine-news-photo/1244267691">Joseph Prezioso/AFP via Getty Images</a></span>
</figcaption>
</figure>
<h2>Swimming into the spotlight</h2>
<p>Before the mid-1970s, much of what was known about sharks came via people who went to sea. In 1958, the U.S. Navy established the <a href="https://www.floridamuseum.ufl.edu/shark-attacks/">International Shark Attack File</a> – the world’s only scientifically documented, comprehensive database of all known shark attacks – to reduce wartime risks to sailors stranded at sea when their ships sank. </p>
<p>Today the file is managed by the <a href="https://www.floridamuseum.ufl.edu/">Florida Museum of Natural History</a> and the <a href="https://elasmo.org/">American Elasmobranch Society</a>, a professional organization for shark researchers. It works to inform the public about shark-human interactions and ways to reduce the risk of shark bites.</p>
<p>In 1962, <a href="https://www.fisheries.noaa.gov/feature-story/john-jack-casey-internationally-recognized-shark-researcher-mentor-and-narragansett">Jack Casey</a>, a pioneer of modern shark research, initiated the <a href="https://www.fisheries.noaa.gov/resource/document/cooperative-shark-tagging-program">Cooperative Shark Tagging Program</a>. This initiative, which is still running today, relied on Atlantic commercial fishermen to report and return tags they found on sharks, so that government scientists could calculate how far the sharks had moved after being tagged. </p>
<p>After “Jaws,” shark research quickly went mainstream. The American Elasmobranch Society was founded in 1982. Graduate students lined up to study shark behavior, and the number of published shark studies <a href="https://thefisheriesblog.com/2015/06/15/thank-you-jaws-the-upside-for-sharks-40-years-later/">sharply increased</a>.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/reel/Cz6muU6u3Mn/?utm_source=ig_web_copy_link\u0026igsh=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Field research on sharks expanded in parallel with growing interest in extreme outdoor sports like surfing, parasailing and scuba diving. Electronic tags enabled researchers to monitor sharks’ movements in real time. DNA sequencing technologies provided cost-effective ways to determine how different species were related to one another, what they were eating and how populations were structured.</p>
<p>This interest also had a sensational side, embodied in the Discovery Channel’s launch in 1988 of <a href="https://www.discovery.com/shark-week">Shark Week</a>. This annual block of programming, ostensibly designed to educate the public about shark biology and counter negative publicity about sharks, was a commercial venture that exploited the tension between people’s deep-seated fear of sharks and their yearning to understand what made these animals tick. </p>
<p>Shark Week featured made-for-TV stories that focused on <a href="https://www.washingtonpost.com/news/arts-and-entertainment/wp/2018/07/26/a-fake-shark-week-documentary-about-megalodons-caused-controversy-why-is-discovery-bringing-it-up-again/">fictional scientific research projects</a>. It was wildly successful and remains so today, in spite of critiques from some researchers who call it <a href="https://theconversation.com/beware-of-shark-week-scientists-watched-202-episodes-and-found-them-filled-with-junk-science-misinformation-and-white-male-experts-named-mike-195180">a major source of misinformation</a> about sharks and shark science.</p>
<h2>Physical, social and genetic insights</h2>
<p>Contrary to the long-held notion that sharks are mindless killers, they exhibit a wide range of traits and behavior. For example, the velvet belly lantern shark communicates through flashes of light from <a href="https://doi.org/10.4161/cib.4.3.14888">organs on the sides of its body</a>. Female hammerhead sharks can <a href="http://dx.doi.org/10.1098/rsbl.2007.0189">clone perfect replicas of themselves</a> without male sperm. </p>
<p>Sharks have the most sensitive electrical detectors thus far discovered in the natural world – networks of pores and nerves in their heads, known as <a href="https://www.scienceandthesea.org/program/201105/ampullae-lorenzini">ampullae of Lorenzini</a>, after Italian scientist Stefano Lorenzini, who first described these features in the 17th century. Sharks use these networks to navigate in the open ocean, <a href="https://doi.org/10.1016/j.cub.2021.03.103">using Earth’s magnetic field for orientation</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three snorkelers swim above a large spotted shark." src="https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572016/original/file-20240129-17-i6lyza.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">Snorkelers swim above a whale shark near the Maldives in the Indian Ocean. The largest fish in the sea, whale sharks are filter feeders that prey on plankton.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/gTntz7">Tchami/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Another intriguing discovery is that some shark species, including makos and blue sharks, <a href="http://dx.doi.org/10.1098/rsbl.2008.0761">segregate by both sex and size</a>. Among these species, cohorts of males and females of different sizes are often found in distinct groups. This finding suggests that some sharks may have <a href="https://www.britannica.com/topic/hierarchy-social-science">social hierarchies</a>, like those seen in some primates and hoofed mammals. </p>
<p>Genetic studies have helped researchers explore questions such as why some sharks <a href="https://theconversation.com/why-do-hammerhead-sharks-have-hammer-shaped-heads-184372">have heads shaped like hammers or shovels</a>. They also show that sharks have the <a href="https://doi.org/10.1038/s41467-023-42238-x">lowest mutation rate of any vertebrate animal</a>. This is notable because mutations are the raw material for evolution: The higher the mutation rate, the better a species can adapt to environmental change. </p>
<p>However, sharks have been around for 400 million years and have been through some of the most extreme environmental changes on earth. It’s not known yet how they have persisted so successfully with such a low mutation rate.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/punSQuf-ZwQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gavin Naylor, director of the Florida Program for Shark Research, describes how DNA analysis provides insights into shark science.</span></figcaption>
</figure>
<h2>The marquee species</h2>
<p>White sharks, the focal species of “Jaws,” attract enormous public interest, although much about them is still unknown. They can live to age 70, and they routinely swim thousands of miles every year. Those in the Western North Atlantic tend to move north-south between Canada and the Gulf of Mexico; white sharks on the U.S. west coast move east-west between California and the Central Pacific. </p>
<p>We now know that juvenile white sharks feed almost exclusively on fishes and stingrays, and don’t start incorporating seals and other marine mammals into their diets until they are the equivalent of teenagers and have grown to about 12 feet long. Most confirmed white shark bites on humans seem to be by animals that are between 12 and 15 feet long. This supports the theory that almost all bites by white sharks on humans are <a href="https://doi.org/10.1098/rsif.2021.0533">cases of mistaken identity</a>, where humans resemble the seals that sharks prey on.</p>
<p><iframe id="9y7JJ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/9y7JJ/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Still in the water</h2>
<p>Although “Jaws” had a <a href="https://www.today.com/popculture/jaws-took-chomp-out-pop-culture-40-years-ago-1d79919594">widespread cultural impact</a>, it didn’t keep surfers and bathers from enjoying the ocean. </p>
<p>Data from the International Shark Attack File on confirmed unprovoked bites by white sharks from the 1960s to the present day shows a continuous increase, although the number of incidents yearly is quite low. This pattern is consistent with growing numbers of people <a href="https://coast.noaa.gov/states/fast-facts/tourism-and-recreation.html">pursuing recreational activities at the coasts</a>. </p>
<p>Around the world, there have been 363 <a href="https://www.floridamuseum.ufl.edu/shark-attacks/maps/world-interactive/">confirmed, unprovoked bites by white sharks</a> since 1960. Of these, 73 were fatal. The World Health Organization estimates that there are <a href="https://www.who.int/news-room/fact-sheets/detail/drowning">236,000 deaths yearly due to drowning</a>, which translates to around 15 million drowning deaths over the same time period. </p>
<p>In other words, people are roughly 200,000 times more likely to drown than to die from a white shark bite. Indeed, surfers are more likely to die in a car crash on the way to the beach than they are to be bitten by a shark.</p><img src="https://counter.theconversation.com/content/220629/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gavin Naylor receives funding from the National Science Foundation and the Lenfest Foundation.</span></em></p>
‘Jaws,’ published in 1974, terrified the public of sharks, but it also brought shark research into the scientific mainstream.
Gavin Naylor, Director of Florida Program for Shark Research, University of Florida
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/220760
2024-01-18T13:28:52Z
2024-01-18T13:28:52Z
Not all underwater reefs are made of coral − the US has created artificial reefs from sunken ships, radio towers, boxcars and even voting machines
<figure><img src="https://images.theconversation.com/files/569704/original/file-20240116-27-b90elk.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5682%2C3788&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The bow of the U.S. Coast Guard cutter Duane, a decommissioned ship deliberately sunk off Florida to serve as an artificial reef.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/bow-of-uscg-duane-royalty-free-image/492717259">Stephen Frink via Getty Images</a></span></figcaption></figure><p>When people hear about underwater reefs, they usually picture colorful gardens created from coral. But some reefs are anchored to much more unusual foundations. </p>
<p>For more than a century, people have placed a wide assortment of objects on the seafloor off the U.S. coast to provide habitat for marine life and recreational opportunities for fishing and diving. Artificial reefs have been created from decommissioned ships, chicken transport cages, concrete pipes, rail cars and more.</p>
<p>We study how ocean-dwelling fish <a href="https://scholar.google.com/citations?user=wZ-kv2AAAAAJ&hl=en">use artificial reefs</a> in the <a href="https://scholar.google.com/citations?user=WF8vzA4AAAAJ">U.S. and beyond</a>. Through our research, we have learned that artificial reefs can be hot spots for large predatory fish such as <a href="https://doi.org/10.1111/faf.12548">groupers</a> and <a href="https://doi.org/10.1371/journal.pone.0237374">jacks</a>. They also can serve as <a href="https://doi.org/10.1038/s42003-019-0398-2">stepping stones</a> for reef fish expanding their range northward with warming water temperatures and as <a href="https://doi.org/10.1002/ecy.2687">rest stops</a> for sharks. </p>
<p>Artificial reefs can be <a href="https://doi.org/10.1002/ecs2.3924">strategically designed and placed</a> to optimize fish habitat. But although they provide valuable ecological services, no one has inventoried how many of these structures exist in U.S. waters or how much seafloor they occupy.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fish swim through a sunken ship doorway rimmed with coral as a scuba diver hovers nearby." src="https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569699/original/file-20240116-25-xly63u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&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 diver at the U.S. Coast Guard cutter Duane, which was decommissioned in 1985 and intentionally sunk in 1987 off Key Largo, Fla., to create reef habitat.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/diver-on-shipwreck-royalty-free-image/109010339">Stephen Frink/The Image Bank via Getty Images</a></span>
</figcaption>
</figure>
<p>To help fill this knowledge gap, we led a team of scientists and artificial reef directors from the 17 U.S. states with artificial reef-building programs in the first national calculation of artificial reef extent. Our <a href="https://www.nature.com/articles/s41893-023-01258-7">new study</a> shows that these reefs cover a total of about 7 square miles (19 square kilometers) of U.S. seafloor – an area equivalent to 3,600 football fields. We also describe the diversity of objects used to create reefs, as well as patterns in artificial reef creation over time.</p>
<h2>Creating modern artificial reefs</h2>
<p>Modern reefing is different from dumping trash into the water and is <a href="https://media.fisheries.noaa.gov/dam-migration/noaa_artificial_reef_guidelines.pdf">regulated at the federal and state levels</a>. A rigorous permitting and approval process ensures that the proposed objects or materials are appropriate to deploy in the ocean. </p>
<p>For example, decommissioned ships are thoroughly <a href="https://www.epa.gov/ocean-dumping/vessel-reef-projects">cleaned and drained of fuel and other polluting substances</a> prior to sinking to minimize environmental risks. Some materials that were once used to create artificial reefs, such as rubber, fiberglass, wood and plastic, are now prohibited because they may move from their placed location, damaging nearby habitat, or deteriorate quickly in salt water. </p>
<p>Reefed objects can be sunk only in predesignated areas of the U.S. seafloor. These zones, which are usually sandy sea bottom, total about 2,200 square miles (5,800 square kilometers) – roughly the area of Delaware.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/48Py7uILHHg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Seven months after the Texas Parks and Wildlife Dept.’s artificial reef program sank the Kraken, a decommissioned 371-foot cargo ship, divers found it heavily colonized by ocean life.</span></figcaption>
</figure>
<p>Each zone can support the creation of many individual reefs over multiple decades. Within a given zone, reefed objects are usually placed away from one another, separated by large swaths of sand. This maximizes the amount of sand habitat, where some reef fish forage.</p>
<p>The extent of artificial reefs in these zones has increased by about 2,000% over the past 50 years. Since 2010, however, artificial reef extent has grown only 12%. This is likely because of challenges in acquiring and sinking acceptable reef materials. It could also reflect a push toward <a href="https://theconversation.com/3d-printing-coral-reefs-can-create-new-habitat-but-it-doesnt-tackle-human-destruction-103927">developing structures</a> specifically for use as artificial reefs. </p>
<h2>Planes, trains and automobiles</h2>
<p>For our study, we gathered records of intentional reefings dating back to 1899 and occurring off artificial all U.S. coastal states, except for six without artificial ocean reef programs: Maine, New Hampshire, Connecticut, Oregon, Washington and Alaska.</p>
<p>For some of these events, especially in recent decades, there were detailed records of the sizes and quantities of sunken objects or seafloor maps from which we could derive these measurements. These reefs were easy to quantify. </p>
<p>Other records, including some from the early 20th century, had scant detail. For these, we developed an approach to estimate how much seafloor the reefs covered, based on similar deployments with better records.</p>
<p>Our study found a vast assortment of reefed objects on the U.S. seafloor. They included decommissioned tugboats, fishing vessels, barges, ferries and military vessels. Reefs have also been created from rail boxcars, aircraft, vehicles, chicken transport cages, voting machines, missile platforms, concrete pipes, radio towers, tires, limestone rocks and objects purposely designed as artificial reefs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A boat with a crane lowers pyramid-shaped structures into the water." src="https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569701/original/file-20240116-19-2hqu7p.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 Florida Fish and Wildlife Commission deploys artificial reef modules off the coast of Mexico Beach on April 6, 2013.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/eh6fXS">Florida Fish and Wildlife Commission/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Objects that occupy the largest amount of seafloor include limestone rocks, large concrete modules designed specifically for reefing, metal rigs and towers and long, narrow concrete pieces repurposed from their previous uses, such as culverts or bridges.</p>
<h2>Potential impacts</h2>
<p>After a reef is created, fish can appear within minutes or hours. The sequence of fish arrival sometimes <a href="https://doi.org/10.1016/j.ecoleng.2018.09.012">follows a pattern</a>. Transient fish such as jacks and barracuda come first, followed by bottom-dwelling fish such as grouper and smaller reef fish. With time, plants and animals grow on the hard surfaces of the artificial reef, helping to provide food and sanctuary for fish.</p>
<p>However, these reefs can also cause ecological harm. Invasive species, such as plants and other animals that grow on hard structures, can use artificial reefs to <a href="https://doi.org/10.1371/journal.pone.0038124">spread to new places</a>. </p>
<p>Artificial reefs also may attract fish away from nearby natural reefs. Since constructed reefs are often in prime recreational fishing locations, this could lead to higher catches of those species. </p>
<p>Another risk is that if artificial reefs are improperly placed or secured on the sea floor, they can shift into unintended areas and harm sensitive habitats, particularly in the aftermath of storms. For example, Florida <a href="https://www.theguardian.com/us-news/2015/may/22/florida-retrieving-700000-tires-after-failed-bid-to-create-artifical-reef">sank 1 million to 2 million tires offshore</a> in the 1970s in an effort to create artificial reefs, but sea life didn’t colonize them as intended. Now the tires are washing around and smothering coral.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/reel/CxvnpSdOnsr/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Learning from artificial reefs</h2>
<p>Monitoring how fish and other species use artificial reefs, especially compared with naturally occurring reefs, will be key for understanding benefits and risks from these structures. As <a href="https://theconversation.com/artificial-coral-reefs-showing-early-signs-they-can-mimic-real-reefs-killed-by-climate-change-new-research-215011">climate change</a> continues to alter ocean ecosystems, we see opportunities to learn which types of artificial reefs are best suited for enhancing habitat for particular sorts of fish. </p>
<p>For example, we know that large predators that dwell in open water, such as jacks, barracuda and sharks, tend to prefer <a href="https://doi.org/10.1371/journal.pone.0237374">taller artificial reefs over shorter ones</a>. This is similar to insights from oil rigs, showing that these vertical and complex structures are <a href="https://doi.org/10.1073/pnas.1411477111">valuable fish habitat</a>. More than 500 decommissioned oil rigs <a href="https://www.bsee.gov/what-we-do/environmental-compliance/environmental-programs/rigs-to-reefs">have been converted to reefs</a>. Our calculation included only those that are managed by state artificial reef programs. </p>
<p>Other structures in the water, such as <a href="https://theconversation.com/as-the-us-begins-to-build-offshore-wind-farms-scientists-say-many-questions-remain-about-impacts-on-the-oceans-and-marine-life-216330">offshore wind turbine foundations</a>, will <a href="https://youtu.be/0SBxDWuE1vY">likely form habitat for sea life</a> similarly to artificial reefs. Insights about what types of structures different fish prefer may help guide the design or location of offshore wind farms.</p>
<p>Humans rely on the ocean for many benefits, including food, commerce, energy and a stable climate. Measuring artificial reefs’ footprint is a first step toward understanding their effects, both good and bad, on ocean wildlife and human uses of the ocean.</p>
<p><em><a href="https://www.nature.org/en-us/about-us/where-we-work/united-states/virginia/stories-in-virginia/our-staff/">Brendan Runde</a>, a marine scientist at The Nature Conservancy, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/220760/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 organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Artificial reefs are structures that humans put in place underwater that create habitat for sea life. A new study shows for the first time how much of the US ocean floor they cover.
Avery Paxton, Research Marine Biologist, National Oceanic and Atmospheric Administration
D'amy Steward, Master's Student in Biology, University of Guam
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/220106
2024-01-09T13:25:50Z
2024-01-09T13:25:50Z
I set out to investigate where silky sharks travel − and by chance documented a shark’s amazing power to regenerate its sabotaged fin
<figure><img src="https://images.theconversation.com/files/567867/original/file-20240104-19-fvz9ed.jpg?ixlib=rb-1.1.0&rect=0%2C114%2C919%2C596&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rather than a tracking tag telling scientists where this shark traveled, its violent removal let them observe an unexpected regeneration process.</span> <span class="attribution"><span class="source">Josh Schellenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>I made an accidental and astonishing discovery while studying the movements of sharks off the coast of Jupiter, Florida. I set out to record the migration routes of silky sharks, named for their smooth skin. Instead, in a story filled with twists and turns, I ended up documenting the rare phenomenon of a shark <a href="https://doi.org/10.1155/2023/6639805">regenerating a dorsal fin</a>. </p>
<h2>Tagging, then trauma</h2>
<p>It all started in the summer of 2022, when my team and I tagged silky sharks (<em>Carcharhinus falciformis</em>) as part of my <a href="https://chelsealeighblack.com/research-projects/biotrack/">Ph.D. research</a>. <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/carcharhinus-falciformis/">Silky sharks</a> are commonly found in the open ocean and grow to be 10 feet long. Scientists know these sharks congregate in South Florida each summer, but where they go the rest of the year remains a mystery – one I hoped to solve. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three scientists wearing latex gloves lean over the side of a boat holding a still shark. Woman in middle attaches a hand-sized tag with an short antena to the fin on the shark's back." src="https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=493&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=493&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=493&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=620&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=620&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=620&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chelsea Black, center, leads a satellite tagging team from the University of Miami in June 2022.</span>
<span class="attribution"><span class="source">Tanner Mansell</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Local boat captain John Moore took us to a site where sharks are known to gather. We carefully caught and gently attached GPS trackers to the dorsal, or top, fin of 10 silky sharks. </p>
<p>The tags, which are attached like large earrings, do not interfere with swimming and are designed to fall off after a few years. When the tag’s antenna breaks the surface of the water, its GPS location is picked up by overhead satellites, hopefully revealing details of the shark’s secret life.</p>
<p>I headed home to track their travels from my laptop. </p>
<p>The story took an unexpected turn a few weeks later, when I received disturbing photos from an avid diver and underwater photographer, Josh Schellenberg, who knew of my work.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Silky shark swiming in water with its dorsal fin missing a chunk of tissue shaped like a satellite tag." src="https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=333&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=333&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=333&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&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 first sighting of the wounded silky shark in July 2022.</span>
<span class="attribution"><span class="source">Josh Schellenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The photos showed a male silky shark with a large, gaping wound in its dorsal fin, as if someone had taken a satellite-tag-shaped cookie cutter and punched it right through. Josh wondered if this individual was one of the sharks from my study. </p>
<p>When placing the GPS tags, I also place a second tag beneath each shark’s dorsal fin that displays a unique ID number, so I was able to confirm the injured shark was one from my study, #409834.</p>
<p>I felt a mixture of relief and sadness. Relief that the shark survived this ordeal; sadness for the scientific data that would now go uncollected. </p>
<p>Silky sharks are often caught by local fishermen in this area but are protected in Florida and <a href="https://myfwc.com/fishing/saltwater/commercial/sharks/">illegal to kill or retain</a>. Josh’s photos of #409834 showed several hooks in his mouth, so I knew this animal had been captured several times since my team tagged him.</p>
<p>The way the satellite tag attaches means it’s impossible for it to naturally rip out of the fin and leave a wound of this shape. Why someone cut off the shark’s satellite tag remains a mystery, but perhaps they thought they could resell it or possibly wanted to interfere with research. I never expected to see that shark again.</p>
<h2>The return of #409834</h2>
<p>Flash forward to one year later, the summer of 2023. I received several photos of silky sharks from John Moore, our boat captain, who is also an avid diver. John was on the lookout for any of our sharks making their seasonal return to Jupiter. In the many shark photos he sent, I noticed a silky shark with an oddly shaped dorsal fin. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Silky shark swimming through water with an oddly shaped dorsal fin." src="https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.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">Shark #409834 spotted a year later, in June 2023, with a healed dorsal fin.</span>
<span class="attribution"><span class="source">Josh Schellenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>I knew immediately it had to be #409834 from the previous summer. A few days later, John was able to get close enough to photograph the ID tag to confirm my hunch. Josh Schellenberg also spotted and photographed #409834. With both John’s and Josh’s photos, I was able to compare the healed dorsal fin with the freshly injured one. </p>
<p>I wasn’t expecting to make a groundbreaking discovery. Simple curiosity led me to start analyzing the photos. But the revelation was astonishing: Not only had the wound completely healed, but the 2023 dorsal fin was 10.7% larger in size than it was after the injury in 2022. New fin tissue had regenerated.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A collage of four photos – two are close ups of the dorsal fin freshly injured in 2022 and two are close ups of it healed in 2023. Much of it has grown back." src="https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Changes in the dorsal fin from 2022 and 2023.</span>
<span class="attribution"><span class="source">Josh Schellenberg and John Moore</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1155/2023/6639805">My analysis</a> determined that within 332 days, the shark regenerated enough tissue that his dorsal fin was almost back to 90% of its original size, growing back more than half of what had been cut off in 2022.</p>
<p>The <a href="https://dlnr.hawaii.gov/sharks/anatomy/fins-swimming/">dorsal fin</a>, pivotal for balance, steering and hydrodynamics, is vital for a shark to be able to hunt and survive. Seeing no infection or any signs of malnourishment in #409834 suggests an extraordinary feat of endurance.</p>
<p>Scientists know that sharks have an incredible <a href="https://doi.org/10.1093/conphys/cov062">aptitude for healing</a> – but mechanisms behind these observations are still poorly understood. While limb regeneration has been widely documented in other marine animals like <a href="https://ssec.si.edu/stemvisions-blog/all-about-starfish">starfish</a> and <a href="https://doi.org/10.1016/j.jembe.2023.151895">crabs</a>, there is only <a href="https://doi.org/10.1093/conphys/coaa120">one other documented case</a> of dorsal fin regeneration in a shark – a whale shark in the Indian Ocean that regrew its dorsal fin after a boat accident in 2006.</p>
<h2>400 million years of resilience</h2>
<p>There’s a reason sharks have been on Earth <a href="https://www.sciencedaily.com/releases/1999/04/990422060147.htm">longer than trees</a> and have survived <a href="https://doi.org/10.1101/2021.01.20.427414">multiple mass extinction events</a> that wiped out other species. They are a product of <a href="https://www.nhm.ac.uk/discover/shark-evolution-a-450-million-year-timeline.html">400 million years</a> of <a href="https://www.floridamuseum.ufl.edu/discover-fish/sharks/fossil/basics/">evolutionary adaptations</a> that demonstrate their remarkable resilience and have primed them for survival.</p>
<p>To be able to pinpoint an ability that helps make them so resilient is a major scientific advance – especially considering scientists are still questioning where silky sharks spend most of their time in the Atlantic. </p>
<p>One person’s attempt to undermine shark science and harm a shark ultimately proved futile. Instead, the shark’s toughness prevailed and led to an amazing discovery about this species. This story also shows there are countless individual people, including scientists like me and shark enthusiasts like Josh and John, who share a genuine love and respect for these animals.</p>
<p>While I’ll never know for certain where #409834 spends the rest of the year, I hope he continues to return to Jupiter each summer so we can further assess his progress. Based on the healing rate calculated in my study, we just might see his dorsal fin grow back to 100% its original size.</p><img src="https://counter.theconversation.com/content/220106/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chelsea Black does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
After scientists’ GPS tracking tag was violently removed from one shark’s dorsal fin, they were in for a surprise: The wound didn’t just heal, but the missing tissue grew back.
Chelsea Black, Ph.D. Candidate in Marine Ecosystems and Society, University of Miami
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/209196
2024-01-08T13:36:16Z
2024-01-08T13:36:16Z
What happens to the ocean if we take out all the fish? A marine ecologist explains the complex roles fish play in their ecosystem
<figure><img src="https://images.theconversation.com/files/543088/original/file-20230816-19-h6b36a.jpg?ixlib=rb-1.1.0&rect=6%2C12%2C2038%2C1348&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fish swim in a reef at Pearl and Hermes Atoll in the Northwestern Hawaiian Islands.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/UNBiodiversity/3ead5d56c624402893c0df11ab789657/photo?Query=ocean%20fish&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=262&currentItemNo=31&vs=true">AP Photo/Jacob Asher </a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>What would happen to the ocean if we took out all the fish? – Reny, age 12</strong></p>
</blockquote>
<hr>
<p>The ocean is massive and covers most of the surface of our planet. In addition to its size, it’s packed with life, ranging from an astounding diversity of plants, microbes, worms, corals and crabs to squids, whales and, yes, even fish. The ocean is full of fish, so much so that they make up the <a href="https://doi.org/10.1073/pnas.1711842115">second-largest amount of all carbon</a> – the material that makes up living things – in the entire animal kingdom. They’re just behind the group containing insects and crustaceans.</p>
<p>Most people only interact with the ocean from a beach or in a boat, so it can be hard to wrap your head around how many fish there really are. But the ocean is swarming with them, from its surface <a href="https://www.nbcnews.com/news/world/deepest-ever-fish-filmed-japan-scientists-rcna77858">to its depths</a>. </p>
<p>These fish also come in all kinds of shapes and sizes, ranging from the tiny sardines, guppies and blennies that you might <a href="https://www.palmbeachpost.com/story/opinion/columns/guest/2020/01/25/point-of-view-call-for-more-diversity-not-only-more-fish-in-marine-protected-areas/112150854/">see on a coral reef</a> to massive tunas and whale sharks that you might find <a href="https://www.fisheries.noaa.gov/feature-story/surface-slicks-are-pelagic-nurseries-diverse-ocean-fauna">out in the open ocean</a>. </p>
<p>These fish perform all kinds of <a href="https://doi.org/10.1002/ecs2.4288">roles in their ecosystems</a> that support the lives of other organisms around them. If they disappeared one day, the ocean would look very different.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542471/original/file-20230813-127481-q0e3vz.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">School of slopehead parrotfish.</span>
<span class="attribution"><span class="source">NOAA, Kevin Lino</span></span>
</figcaption>
</figure>
<p>I’m a <a href="https://koryevans.weebly.com/">scientist who studies fish</a>, their diversity and all the ways they contribute to ocean environments.</p>
<h2>Fish as food</h2>
<p>Fish play important roles as both <a href="https://www.noaa.gov/education/resource-collections/marine-life/aquatic-food-webs">predators and prey</a> in ocean ecosystems. Thousands of species throughout the ocean and terrestrial ecosystems rely on fish for food – <a href="https://www.fisheries.noaa.gov/feature-story/economic-importance-seafood">including people</a>. </p>
<p>In coral reef ecosystems, small fish are eaten by larger fish and other marine animals. This means the little fish form the base of the food web – they provide energy to the bigger fish and other creatures. </p>
<figure class="align-center ">
<img alt="Conceptual food web of a coral reef ecosystem identifying key functional groups." src="https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=569&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=569&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=569&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=715&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=715&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542472/original/file-20230813-197557-ebgabl.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=715&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Links between different species of coral reef animals.</span>
<span class="attribution"><span class="source">Global Change Biology, Rogers et al., 2015</span></span>
</figcaption>
</figure>
<p>Outside of the water, many birds, mammals and reptiles eat fish and rely on them as an <a href="https://doi.org/10.1016/S0921-8009(99)00015-4">essential source of protein</a>. </p>
<p>Even land plants can benefit from the presence of fish. On the western coast of the United States, salmon returning to small streams after spending several years at sea function as a conveyor belt of nutrients. The salmon feed not only animals that catch them, like bears, but also the plants that border the streams. Studies have shown that some plants get <a href="https://www.adfg.alaska.gov/index.cfm?adfg=wildlifenews.view_article&articles_id=407">70% of their nitrogen</a> from salmon that die on or near the river banks. </p>
<p>Humans also depend on fish as a food source. Fish and other seafood products are an important protein source for <a href="https://www.nature.org/en-us/what-we-do/our-priorities/provide-food-and-water-sustainably/food-and-water-stories/global-fisheries/">nearly 3 billion people</a>. Human populations have been eating and following fish around the world for <a href="https://doi.org/10.1073/pnas.1710186114">thousands of years</a>. </p>
<h2>Fish maintain habitats</h2>
<p>Fish are also more than just food. As fish themselves forage for food, they can create and maintain important <a href="https://doi.org/10.1007/s00338-006-0112-y">habitats for other organisms</a>. In coral reef ecosystems, plant-eating fish control the growth of algae by constantly grazing it down. Without the help of these herbivores, or plant-eating fish, the algae would rapidly grow and smother the coral, effectively killing it. </p>
<p>One type of herbivorous fish, the parrotfish, <a href="https://ocean.si.edu/ocean-life/fish/tough-teeth-and-parrotfish-poop">feeds directly on the corals</a>. At first, this may seem bad for the corals, but the grazing done by parrotfish can actually increase a coral colony’s rate of growth. And <a href="https://ocean.si.edu/ocean-life/fish/tough-teeth-and-parrotfish-poop">the poop</a> – yes, the poop – from parrotfish has been shown to be <a href="https://doi.org/10.1016/j.tim.2022.03.006">particularly nutritious</a> for corals. Parrotfish poop also forms part of the <a href="https://ocean.si.edu/ocean-life/fish/tough-teeth-and-parrotfish-poop">beautiful white sand beaches</a> that you may have enjoyed on a family vacation.</p>
<p>Other fish create habitats for other animals and influence their environment by <a href="https://www.ingentaconnect.com/content/umrsmas/bullmar/1986/00000038/00000001/art00006">disturbing sand</a> while they feed. By moving the sand around, they’re exposing tiny organisms hiding in the sand, which other animals can eat. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/_pN5-96nduge?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Some fish sift through sand to find their food. That creates more opportunities for other creatures to find food in the sand.</span></figcaption>
</figure>
<p>Despite the fact that many types of fish are confined to the ocean, their presence can be felt across many habitats. They can directly and indirectly affect the lives of the organisms that depend on them for food and shelter. Without fish, Earth would gradually lose its beautiful white sand beaches, the coral reef ecosystems would be overgrown with algae, lots of people would run out of food to eat, and we would lose some of the planet’s most fascinating creatures.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/209196/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kory Evans receives funding from National Science Foundation. </span></em></p>
There are so many fish in the ocean that if you took them out, important habitats and food sources for many creatures would be lost.
Kory Evans, Assistant Professor of BioSciences, Rice University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/214688
2023-12-19T18:13:36Z
2023-12-19T18:13:36Z
Shipwrecks teem with underwater life, from microbes to sharks
<figure><img src="https://images.theconversation.com/files/555600/original/file-20231024-25-xo8h4f.jpg?ixlib=rb-1.1.0&rect=30%2C15%2C5061%2C3534&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A school of grunts on a sunken World War II German submarine in the Atlantic Ocean off North Carolina.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/diver-and-schooling-tomtates-on-wwii-u-352-german-royalty-free-image/153943111">Karen Doody/Stocktrek Images via Getty Images</a></span></figcaption></figure><p>Humans have sailed the world’s oceans for thousands of years, but they haven’t all reached port. Researchers estimate that there are <a href="https://unesdoc.unesco.org/ark:/48223/pf0000152883">some three million shipwrecks</a> worldwide, resting in shallow rivers and bays, coastal waters and the deep ocean. Many sank during catastrophes – some during storms or after running aground, others in battle or collisions with other vessels.</p>
<p>Shipwrecks like <a href="https://www.britannica.com/topic/Titanic">the RMS Titanic</a>, <a href="https://www.britannica.com/topic/Lusitania-British-ship">RMS Lusitania</a> and <a href="https://www.britannica.com/technology/monitor-ship-type#ref51448">USS Monitor</a> conjure tales of human courage and sacrifice, sunken treasure and unsolved mysteries. But there’s another angle to their stories that doesn’t feature humans. </p>
<p>I have <a href="https://scholar.google.com/citations?user=wZ-kv2AAAAAJ&hl=en">studied the biology of shipwrecks</a> in the United States and internationally for 14 years. From this work, I have learned that shipwrecks are not only cultural icons but can also be biological treasures that create habitat for diverse communities of underwater life. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FTYyzAxt3JI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The USS Monitor, which sank off Cape Hatteras, North Carolina, in a storm on Dec. 31, 1862, is now a center for sea life.</span></figcaption>
</figure>
<p>Recently, I led an international team of biologists and archaeologists in disentangling the mysteries of how this transformation happens. Drawing on scientific advances from our team and international colleagues, our <a href="https://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/biad084">new study</a> describes how wrecked vessels can have second lives as seabed habitats.</p>
<h2>A new home for underwater life</h2>
<p>Ships are typically made of metal or wood. When a vessel sinks, it adds foreign, artificial structure to the seafloor. </p>
<p>For example, the World War II tanker <a href="https://monitor.noaa.gov/shipwrecks/clark.html">E.M. Clark</a> sank on a relatively flat, sandy seabed in 1942 when it was torpedoed by a German submarine. To this day, the intact metal wreck looms over the North Carolina seafloor like an underwater skyscraper, creating an island oasis in the sand. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Bx_uzNvNU1s?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In this video narrated by NOAA research scientist Avery Paxton, sand tiger sharks hover above the wreck of the E.M. Clark off North Carolina, with vermilion snapper schooling nearby. Jacks and an invasive lionfish also appear.</span></figcaption>
</figure>
<p>The creatures that reside on and around sunken ships are so diverse and abundant that scientists often colloquially call these sites “<a href="https://3d-shipwreck-data-viewer-noaa.hub.arcgis.com/">living shipwrecks</a>.” Marine life ranging from microscopic critters to some of the largest animals in the sea use shipwrecks as homes. Brilliantly colored corals and sponges blanket the wrecks’ surfaces. Silvery schools of baitfish dart and shimmer around the structures, chased by sleek, fast-moving predators. Sharks sometimes cruise around wrecks, likely resting or looking for prey. </p>
<h2>The origin of a second life</h2>
<p>A ship’s transformation from an in-service vessel into a thriving metropolis for marine life can seem like a fairy tale. It has a once-upon-a-time origin story – the wrecking event – and a sequence of life arriving on the sunken structure and beginning to blossom.</p>
<p>Tiny microbes invisible to the naked human eye initially settle on the wreck’s surface, forming a carpet of cells, called a <a href="https://www.britannica.com/science/biofilm">biofilm</a>. This coating helps to <a href="https://doi.org/10.3389/fmars.2019.00048">make the wreck structure suitable</a> for larval animals like sponges and corals to settle and grow there.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Shellfish, deepwater coral and anemones cling to the surface of a sunken wreck." src="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?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">Diverse sea creatures living on the 19th-century, wooden-hulled Ewing Bank wreck, which lies 2,000 feet (610 meters) deep in the Gulf of Mexico.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/19microbial-stowaways/background/archaeology/media/img2-hires.jpg">NOAA</a></span>
</figcaption>
</figure>
<p>Larger animals like fish sometimes appear within minutes after a ship sinks. <a href="https://coastalscience.noaa.gov/news/artificial-reefs-may-help-tropical-fish-expand-geographic-range-video/">Small fish</a> hide in the structure’s cracks and crevices, while <a href="https://doi.org/10.1016/j.fooweb.2020.e00147">large sharks</a> glide around it. <a href="https://doi.org/10.1016/j.marenvres.2020.104916">Sea turtles</a> and marine mammals such as <a href="https://doi.org/10.1371/journal.pone.0130581">fur seals</a> have also been spotted on wrecks.</p>
<h2>Hot spots for biodiversity</h2>
<p>Shipwrecks host quantities and varieties of marine life that can make them hot spots for biodiversity. The microbes that transform the wreck structure into habitat also enrich the surrounding sand. Evidence from deep Gulf of Mexico wrecks shows that a <a href="https://doi.org/10.1038/s41396-021-00978-y">halo of increased microbial diversity</a> radiates outward anywhere from 650 to 1,000 feet (200-300 meters) from the wreck. In the Atlantic Ocean, <a href="https://doi.org/10.1111/faf.12548">thousands of grouper</a>, a type of reef fish highly valued by fishers, congregate around and inside shipwrecks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fish hover above a wrecked ship's surface." src="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.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"></a>
<figcaption>
<span class="caption">Groupers and a conger eel, bottom center, on the wreck of the German submarine U-576 off the coast of North Carolina.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/16battlefield/logs/sept7/sept7.html">NOAA</a></span>
</figcaption>
</figure>
<p>Shipwrecks can also serve as stepping stones across the ocean floor that animals use as temporary homes while moving from one location to another. This has been documented in areas of the world with dense concentrations of shipwrecks, such as off North Carolina, where storms and war have sunk hundreds of ships.</p>
<p>In this part of the ocean, popularly known as the “<a href="https://www.ncpedia.org/graveyard-atlantic">Graveyard of the Atlantic</a>,” reef fish likely <a href="https://doi.org/10.1038/s42003-019-0398-2">use the islandlike shipwrecks as corridors</a> when moving north or south away from the equator to find favorable water temperatures as climate change <a href="https://theconversation.com/ocean-heat-is-at-record-levels-with-major-consequences-174760">warms the oceans</a>. Scientists have also observed <a href="https://doi.org/10.1002/ecy.2687">sand tiger sharks</a> traveling from one wreck to another, possibly using the shipwrecks like rest stops during migration.</p>
<p>In the deep sea, life growing on shipwrecks can even generate energy. Tube worms that grow on organic shipwreck materials such as paper, cotton and wood host symbiotic bacteria that produce chemical energy. Such tube worm colonies have been documented in the Gulf of Mexico on the steel <a href="https://www.boem.gov/sites/default/files/boem-newsroom/Library/Ocean-Science/Ocean-Science-Jul-Aug-Sep-2014.pdf">luxury yacht Anona</a>. </p>
<h2>Biological mysteries abound</h2>
<p>Despite their biological value, shipwrecks can also threaten underwater life by altering or destroying natural habitats, causing pollution and spreading invasive species.</p>
<p>When a ship sinks, it can damage existing seafloor habitats. In a well-documented case in the Line Islands of the central Pacific, an <a href="https://doi.org/10.1038/ismej.2011.114">iron shipwreck</a> sank on a healthy coral reef. The iron infusion substantially decreased coral cover, and the reef was overcome by algae.</p>
<p>Ships may carry pollutants as fuel or cargo. As shipwrecks deteriorate in seawater, there is a risk that these pollutants may be released. The <a href="https://doi.org/10.1016/j.marpolbul.2021.112087">level of risk</a> depends on how much of the pollutant the ship was carrying and how intact the wreck is. One recent investigation revealed that effects from shipwreck pollutants can be detected in microbes up to <a href="https://doi.org/10.3389/fmars.2022.1017136">80 years after the wreck</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/JTq4b9c3Z00?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Ships and planes wrecked in wartime can leak toxic materials for decades after they come to rest in the ocean.</span></figcaption>
</figure>
<p>Shipwrecks may also inadvertently assist the spread of invasive plants and animals that wreak biological havoc. Wrecks are new structures that invasive species can settle on, grow and use as a hub to expand to other habitats. <a href="https://doi.org/10.1016/j.marpolbul.2020.111394">Invasive cup coral</a> has spread on World War II shipwrecks off Brazil. In Palmyra Atoll in the Pacific, a type of anemone called a corallimorph <a href="https://doi.org/10.1371/journal.pone.0002989">rapidly invaded</a> a shipwreck and now <a href="https://doi.org/10.1007/s10530-018-1696-1">threatens healthy coral reefs</a>.</p>
<h2>The future of shipwreck exploration</h2>
<p>Shipwrecks create millions of study sites that scientists can use to ask questions about marine life and habitats. One of the greatest challenges is that many wrecks are undiscovered or in remote locations. Advances in technology can help researchers see into the most inaccessible areas of the ocean, not only to find shipwrecks but to better understand their biology. </p>
<p>Maximizing discovery will require biologists, archaeologists and engineers to work together to explore these special habitats. Ultimately, the more we learn, the more effectively we can conserve these historical and biological gems.</p><img src="https://counter.theconversation.com/content/214688/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Avery Paxton is affiliated with NOAA National Centers for Coastal Ocean Science. </span></em></p>
When ships sink, they add artificial structures to the seafloor that can quickly become diverse, ecologically important underwater communities.
Avery Paxton, Research Marine Biologist, National Oceanic and Atmospheric Administration
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/218676
2023-11-28T16:39:54Z
2023-11-28T16:39:54Z
As seas get warmer, tropical species are moving further from the equator
<figure><img src="https://images.theconversation.com/files/562152/original/file-20231128-19-rsqe9k.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C3982%2C2568&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As sea turtles move away from the tropics, they're overeating seagrass meadows.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/feeding-time-green-sea-turtle-312723371">Laura Dts / shutterstock</a></span></figcaption></figure><p>Climate change is causing tropical species in the ocean to move from the equator towards the poles, while temperate species recede. This mass movement of marine life, termed <a href="https://doi.org/10.1016/j.tree.2023.10.006">tropicalisation</a>, is leading to a cascade of consequences for ecosystems and biodiversity, and has the potential to impact the global economy.</p>
<p>My colleagues and I recently identified and reviewed 215 tropicalisation-related scientific papers published between 2003 and 2023. Our work, now published in the journal <a href="https://doi.org/10.1016/j.tree.2023.10.006">Trends in Ecology and Evolution</a>, reveals the extent of this species movement, and demonstrates just how widespread its consequences can be.</p>
<p>Tropicalisation is a global trend, fuelled by climate change-induced increases in sea temperatures and <a href="https://www.nature.com/articles/d41586-023-00924-2">marine heatwaves</a>. It is particularly apparent in the regions where strong currents <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2014.0846">flow away from the equator</a>. For example, the Kuroshio Current in the Western Pacific has helped certain <a href="https://doi.org/10.1073/pnas.1716826115">corals and fish</a> to move from the tropics into temperate Japanese waters. </p>
<p>However, other regions of the world where such currents are absent can also experience tropicalisation. A notable example is <a href="https://doi.org/10.1073/pnas.1902181116">mangrove trees</a> expanding northward along the coast of Florida as winter temperatures rise. These trees are typically sensitive to freezing conditions, but can now survive at higher latitudes, where they are replacing salt marshes.</p>
<h2>Marine life on the move</h2>
<p>Tropicalisation involves a wide range of marine life from large habitat forming groups such as corals, algae or mangrove trees, through to marine snails, reptiles and even mammals, among many others. Nevertheless, species involved tend to have some things in common. </p>
<p>Those which are able to move into warming seas such as some <a href="https://doi.org/10.1111/jbi.14744">marine snails</a> or <a href="https://doi.org/10.1111/gcb.15221">coral reef fishes</a> are good dispersers, typically able to travel further in search of suitable habitat. Simultaneously, tropical species that are more generalist in what they eat and how they behave can perform better in their new range. For example, <a href="https://doi.org/10.1111/gcb.15221">coral reef fishes with broader diets</a> are more successful at establishing in the new range as they are more likely to find a source of food.</p>
<p><strong>Where tropicalisation has been detected around the world:</strong></p>
<h2>Ecological and evolutionary consequences</h2>
<p>Tropicalisation can impact an individual population, a whole species or even entire ecosystems. For example, as herbivorous fishes move away from the equator they <a href="https://doi.org/10.1098/rspb.2014.0846">eat lots of algae</a> they find in their new home. This creates additional space for corals to settle in the area, contributing to further tropicalisation. And as <a href="https://doi.org/10.1093/biosci/biw111">tropical sea turtles and dugongs</a> (a cousin of the manatee) expand southwards along Australia’s west coast, they are expected to greatly increase the pressure on already vulnerable seagrass meadows through their consumption.</p>
<p>Some animals are adapting their behaviour. For instance, as tropical damselfishes go further from the equator along south-eastern Australia, they start <a href="https://doi.org/10.1111/1365-2656.13599">forming shoals with temperate species</a> instead of sticking to their usual groups of tropical peers. This change in behaviour is thought to be linked to them <a href="https://doi.org/10.1111/gcb.14016">living longer and growing larger</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Turtle under a rock" src="https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=323&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=323&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=323&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=406&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=406&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562142/original/file-20231128-21-qioibr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=406&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sea turtles are on the move and are eating so much seagrass they are contributing to a global decline.</span>
<span class="attribution"><span class="source">Marc Rius</span></span>
</figcaption>
</figure>
<p>Recent investigations have just begun to unveil the genetic and evolutionary consequences of tropicalisation. For instance, if <a href="https://doi.org/10.1111/jbi.14744">established temperate species are pushed out</a> that may lead to a <a href="https://doi.org/10.1016/j.marenvres.2018.04.013">loss of unique genetic diversity</a>, which can leave the population less able to adapt to future changes. Meanwhile, some temperate species are already adapting to new tropical neighbours. For instance, volcano barnacles in temperate waters off Baja California, Mexico have been observed “<a href="https://doi.org/10.1111/jbi.14716">bending</a>” to fend off tropical predatory snails.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bent barnacles attached to rock" src="https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=339&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=339&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=339&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=426&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=426&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562143/original/file-20231128-27-lzgpbx.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=426&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These barnacles have learned to bend over to stop tropical sea snails – a new arrival in these waters – accessing an opening in their shells.</span>
<span class="attribution"><span class="source">Phillip Fenberg</span></span>
</figcaption>
</figure>
<h2>The socio-economic consequences</h2>
<p>Whether the consequences of tropicalisation are positive or negative will depend on the geographic region and the stakeholders in question. The widespread movement of marine life is already impacting global fisheries, with regions like the western Pacific Ocean experiencing <a href="https://link.springer.com/article/10.1007/s10641-021-01162-z">increased catches of tropical species</a>. However, tropicalisation is also leading to a <a href="https://doi.org/10.1016/j.marenvres.2023.106013">loss of commercially important</a> temperate species and an increase in <a href="https://link.springer.com/article/10.1007/s00003-018-1171-z">non-target species being accidentally caught in fishing hauls</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Coral reef with lots of fish" src="https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562153/original/file-20231128-24-7uuof8.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"></a>
<figcaption>
<span class="caption">As tropical herbivores move away from the equator, they help corals establish themselves at higher latitudes too.</span>
<span class="attribution"><span class="source">Karolina Zarzyczny</span></span>
</figcaption>
</figure>
<p>Meanwhile, the proliferation of mangrove trees contributes to enhanced <a href="https://doi.org/10.1016/j.ecss.2012.12.007">carbon storage and sequestration</a>, compared to the temperate saltmarshes they replace. And the expansion of charismatic tropical species such as corals and the colourful marine life which they host, could help local economies through <a href="https://doi.org/10.1111/1365-2435.13310">increased tourism</a>.</p>
<p>As the latest UN climate summit unfolds, our changing climate means we urgently need more investigations into tropicalisation and better-informed actions to deal with it. While existing research sheds light on its ecological impacts, significant gaps persist in understanding its evolutionary consequences and their interplay with complex socioeconomic impacts. Tropicalisation is a worldwide phenomenon happening right now, and it demands our attention.</p><img src="https://counter.theconversation.com/content/218676/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karolina Zarzyczny receives funding from the Natural Environmental Research Council (grant NE/S007210/1).</span></em></p>
Global marine life is on the move with significant consequences – new study.
Karolina Zarzyczny, PhD Candidate, Marine Tropicalisation, University of Southampton
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/218253
2023-11-24T02:53:56Z
2023-11-24T02:53:56Z
Australian dolphins have the world’s highest concentrations of ‘forever chemicals’
<figure><img src="https://images.theconversation.com/files/561466/original/file-20231123-15-7lw4an.JPG?ixlib=rb-1.1.0&rect=89%2C19%2C4185%2C2824&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Burrunan dolphin</span> <span class="attribution"><a class="source" href="https://www.marinemammal.org.au/gallery">Marine Mammal Foundation</a></span></figcaption></figure><p>As predators at the top of the food chain, dolphins tend to <a href="https://www.sciencedirect.com/topics/chemistry/bioaccumulation#:%7E:text=Bioaccumulation%20is%20a%20process%20of,dietary%20intake%20(trophic%20transfer).">accumulate and magnify</a> high levels of toxins and other chemicals in their bodies. So health problems in dolphins can be a warning that all is not well in the system as a whole. </p>
<p>One group of persistent pollutants has been dubbed “forever chemicals” because they almost never break down in the environment. Commonly known by the acronym PFAS, these per- and polyfluorinated substances are globally recognised as an environmental hazard and a <a href="https://doi.org/10.1002/etc.4890">potential human health issue</a>.</p>
<p>In our new research, we found dolphins with the <a href="https://doi.org/10.1016/j.scitotenv.2023.168438">highest concentration of PFAS</a> in the world live in Australian waters. One young Burrunan dolphin had liver concentrations almost 30% higher than any other dolphin ever reported.</p>
<p>This is a critically endangered species endemic to southeast Australia. While the consequences for dolphin health and the implications for humans remain unknown, the record-breaking concentrations are cause for alarm. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1727178088075972892"}"></div></p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/controversial-forever-chemicals-could-be-phased-out-in-australia-under-new-restrictions-heres-what-you-need-to-know-210697">Controversial ‘forever chemicals’ could be phased out in Australia under new restrictions. Here’s what you need to know</a>
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</p>
<hr>
<h2>The case of the Burrunan dolphin</h2>
<p>The Burrunan dolphin was recognised as a <a href="https://doi.org/10.1371/journal.pone.0024047">separate species in 2011</a>. Fewer than 200 individuals remain. Two small, isolated and genetically distinct populations reside in coastal Victoria, Australia. </p>
<p>In <a href="https://doi.org/10.1016/j.scitotenv.2023.168438">our research</a>, we took liver samples from Burrunan dolphins and three other dolphin species found dead and washed up on beaches. </p>
<p>We found the critically endangered <a href="https://www.marinemammal.org.au/burrunan-dolphin">Burrunan dolphin</a> had 50–100 times more PFAS than other dolphins in the same region. Their PFAS concentrations were the highest reported globally. </p>
<p>In 90% of these dolphins, the liver concentrations of these chemicals (1,020–19,500 nanograms per gram) were above those thought to cause <a href="https://doi.org/10.1021/acs.est.5b06076">liver toxicity</a> and <a href="https://doi.org/10.1002/etc.2122">altered immune responses</a>. </p>
<p>These record-breaking and potentially health-compromising PFAS concentrations are a major concern for the survival of the species. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graphic illustrating the results of PFAS testing in Victorian dolphins" src="https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=232&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=232&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=232&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=291&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=291&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=291&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 Burrunan dolphin had the highest global PFAS concentrations in the study.</span>
<span class="attribution"><a class="source" href="https://www.sciencedirect.com/science/article/pii/S0048969723070663?via%3Dihub">Science of The Total Environment</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Results from Australia and around the world</h2>
<p>By far the highest PFAS concentrations in the dolphins we studied were of a particular compound called PFOS (perfluorooctane sulfonate). PFOS is one of the most studied PFAS compounds. It is listed on the <a href="https://chm.pops.int/Implementation/IndustrialPOPs/PFAS/Overview/tabid/5221/Default.aspx">Stockholm Convention</a>, a global treaty on environmental pollutants, with international restrictions on use. </p>
<p>While Australia does not manufacture PFOS, heavy use of PFOS-containing firefighting foams occurred until the early 2000s. The Australian government <a href="https://www.epa.vic.gov.au/for-community/environmental-information/pfas/pfas-use-in-australia#:%7E:text=While%20PFOS%2C%20PFOA%20and%20other,as%20mist%20suppressants%20and%20coatings.">still allows PFOS import</a> for permitted purposes, such as mist suppressants in manufacturing and metal plating. </p>
<p>In recent years, public concern has prompted <a href="https://doi.org/10.1016/j.canep.2022.102296">ongoing investigations</a> into areas of high firefighting foam use, such as Royal Australian Airforce training facilities and airports. </p>
<p>While firefighting foam is a probable source of PFAS in waterways, there are others. <a href="https://theconversation.com/pfas-forever-chemicals-are-getting-into-ocean-ecosystems-where-dolphins-fish-and-manatees-dine-we-traced-their-origins-216254">Recent research in Florida</a> in the United States found leaking septic and wastewater systems in urban areas were sources of PFAS runoff into the aquatic environment. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pfas-forever-chemicals-are-getting-into-ocean-ecosystems-where-dolphins-fish-and-manatees-dine-we-traced-their-origins-216254">PFAS 'forever chemicals' are getting into ocean ecosystems, where dolphins, fish and manatees dine – we traced their origins</a>
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</em>
</p>
<hr>
<p>The Burrunan dolphins are not alone. In 2017, the <a href="https://www.epa.sa.gov.au/files/12580_report_pfas_marine.pdf">South Australian Environment Protection Authority investigated</a> PFOS concentrations in dolphins from Western Australia, South Australia and New South Wales. Dolphins in the Swan-Canning River Estuary in Perth, and in Port River or Barker Inlet, SA, had high PFOS levels (2,800–14,000ng per gram and 510–5,000ng per gram, respectively). These PFOS levels are similar to those in the Burrunan dolphin (between 494ng and 18,700ng per gram).</p>
<p>The globally significant PFAS and PFOS concentrations in multiple Australian dolphin populations demonstrates potential widespread contamination. This highlights our limited understanding of the short- and long-term consequences in our oceans and estuaries. </p>
<p>It is crucial we understand where different PFAS compounds are coming from, particularly PFOS, and whether the contamination is from a time when we didn’t know better (known as legacy sources) or if we are still releasing them. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1725198561069912240"}"></div></p>
<h2>Isn’t PFOS getting banned anyway?</h2>
<p>The Australian government has <a href="https://theconversation.com/controversial-forever-chemicals-could-be-phased-out-in-australia-under-new-restrictions-heres-what-you-need-to-know-210697">expressed an intention</a> to further regulate PFOS and two other PFAS. This marks a significant step forward. However, the problem with forever chemicals is they will be around for a really long time. </p>
<p>Typically, these chemicals are substituted with alternatives believed to be less detrimental, but unfortunately that is not always the reality. For example, early replacements for PFOS were initially thought to be less readily absorbed by body tissues and pose lower health concerns. But <a href="https://doi.org/10.1021%2Facs.est.3c00374">studies</a> have shown their high <a href="https://www.merriam-webster.com/dictionary/biomagnification">biomagnification</a> potential (with levels increasing higher up the food chain) and accompanying <a href="https://doi.org/10.1016/j.envint.2023.107846">health risks</a>.</p>
<p>While PFOS levels were highest in the Burrunan dolphins we studied, emerging contaminants such as PFMPA, PFECHS, and 6:2 Cl-PFESA were also detected. The presence of these emerging and replacement compounds in dolphins shows they are accumulating within our waterways and suggests it is more than our historic usage that might be a problem. </p>
<h2>It’s not too late</h2>
<p>Dolphins are the “canary in the coal mine” for coastal ecosystems. They live their lives in these inshore waterways and they consume tonnes of fish within their lifetimes. Finding these alarming contaminant concentrations is an important first step to highlighting the problem. </p>
<p>So now we know there’s a problem, we need to ask why. Then we need to determine what can be done about it. </p>
<p>The next step is mapping sources of PFAS so we can more effectively manage this threat to our wildlife and ecosystems. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-found-long-banned-pollutants-in-the-very-deepest-part-of-the-ocean-204447">We found long-banned pollutants in the very deepest part of the ocean</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/218253/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chantel Foord receives funding from a Holsworth Wildlife Research Endowment Grant. She is affiliated with the Marine Mammal Foundation. </span></em></p>
Researchers are finding alarming concentrations of persistent pollutants such as PFAS in Australian dolphins. These record-breaking levels are cause for concern.
Chantel Foord, Research Associate, Marine Mammal Foundation, PhD researcher, RMIT University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/217856
2023-11-21T21:53:50Z
2023-11-21T21:53:50Z
Oxygen 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>
<hr>
<figure class="align-right ">
<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">
<figcaption>
<span class="caption"></span>
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</figure>
<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>
<hr>
<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/216330
2023-11-15T13:22:37Z
2023-11-15T13:22:37Z
As the US begins to build offshore wind farms, scientists say many questions remain about impacts on the oceans and marine life
<figure><img src="https://images.theconversation.com/files/558700/original/file-20231109-19-jiiump.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C5020%2C2988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A row of monopiles that will be the base for offshore wind turbines, in the Atlantic Ocean off the coast of Martha's Vineyard, Mass. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/new-bedford-ma-a-row-of-mono-piles-that-will-be-the-base-news-photo/1623091024">David L Ryan/The Boston Globe via Getty Images</a></span></figcaption></figure><p><em>As renewable energy production expands across the U.S., the environmental impacts of these new sources are receiving increased attention. In a <a href="https://nap.nationalacademies.org/catalog/27154/potential-hydrodynamic-impacts-of-offshore-wind-energy-on-nantucket-shoals-regional-ecology">recent report</a>, the National Academies of Sciences, Engineering, and Medicine examined whether and how constructing offshore wind farms in the Nantucket Shoals region, southeast of Massachusetts, could affect critically endangered North Atlantic right whales. The Conversation asked marine scientists <a href="https://scholar.google.com/citations?user=VRlWQ7QAAAAJ&hl=en">Erin L. Meyer-Gutbrod</a>, <a href="https://scholar.google.com/citations?user=_GGEmncAAAAJ&hl=en">Douglas Nowacek</a>, <a href="https://scholar.google.com/citations?user=U7NE0fUAAAAJ&hl=en">Eileen E. Hofmann</a> and <a href="https://www.researchgate.net/profile/Josh-Kohut">Josh Kohut</a>, all of whom served on the study committee, to explain the report’s key findings.</em></p>
<h2>Why did this study focus on such a specific site?</h2>
<p>The <a href="https://www.boem.gov/">Bureau of Ocean Energy Management</a>, which is part of the U.S. Department of the Interior and regulates offshore energy production, asked the National Academies to conduct this study. Regulators wanted to better understand how installing and operating offshore, fixed-bottom wind turbine generators would affect physical oceanographic processes, such as tides, waves and currents, and in turn how those changes could affect the ecosystem. </p>
<p>For example, offshore wind turbines decrease wind speeds behind them, and the presence of their structures makes the water more turbulent. These changes could affect ocean currents, surface wind speeds and other factors that influence <a href="https://www.allthescience.org/what-is-hydrodynamics.htm">hydrodynamics</a> – the structure and movement of the water around the turbines.</p>
<p>The <a href="https://dbpedia.org/page/Nantucket_Shoals">Nantucket Shoals</a> region is a large, shallow area in the Atlantic that extends south of Cape Cod. Our report focused on it because this is the first large-scale offshore wind farm area in the U.S., and the region has been included in several recent hydrodynamic modeling studies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing nine offshore leasing areas near Nantucket Shoals" src="https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559409/original/file-20231114-23-1q60k9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of the Nantucket Shoals region, showing current wind-power lease areas (colored zones) and water depth contours (red and white lines) in meters.</span>
<span class="attribution"><a class="source" href="https://nap.nationalacademies.org/read/27154/chapter/2">NASEM 2023</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why are North Atlantic right whales of special concern?</h2>
<p>North Atlantic right whales <a href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale">are critically endangered</a>. Scientists estimate that the population is down to <a href="https://www.fisheries.noaa.gov/s3/2023-10/TM314-508-0.pdf">just 356 animals</a>. </p>
<p>This species was <a href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale">almost driven to extinction</a> after centuries of commercial whaling. Even though the whales have been protected from whaling for almost 100 years, they are still accidentally killed when they are <a href="https://www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-vessel-strikes-north-atlantic-right-whales">hit by vessels</a> or <a href="https://doi.org/10.1111/csp2.12736">become entangled in fishing gear</a>. These two sources of mortality are responsible for most documented juvenile and adult right whale <a href="https://doi.org/10.25923/42zk-w456">deaths over the past 25 years</a>. </p>
<p>There are options for protecting them, such as <a href="https://www.fisheries.noaa.gov/feature-story/rule-amend-north-atlantic-right-whale-vessel-speed-regulations-closed-comment">slowing or rerouting boats</a>, shortening the fishing season or even <a href="https://theconversation.com/high-tech-fishing-gear-could-help-save-critically-endangered-right-whales-115974">modifying fishing gear</a> to make it more whale-safe. However, regulators need to know where the whales are going to be and when they’ll be there, so they can put those protections in place. </p>
<p>It’s usually hard to figure out where whales are – they have a large habitat and spend most of their time below the surface of the water, where observers can’t see them. Recently it’s gotten even harder, because climate change is causing whales to <a href="https://doi.org/10.5670/oceanog.2021.308">shift where and when they feed</a>. </p>
<p>Currently, right whales are <a href="https://doi.org/10.1038/s41598-022-16200-8">spending more time around the Nantucket Shoals region</a>. This means scientists and managers need to make sure that wind energy development in the area is happening safely and that threats to whales in the area are reduced.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6Pjj094pfCQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">North Atlantic right whales are critically endangered, mainly by boat strikes and entanglement in fishing gear.</span></figcaption>
</figure>
<h2>How might offshore wind farms affect right whales in the study area?</h2>
<p>Right whales are filter feeders that consume huge quantities of <a href="https://eol.org/pages/46532540/articles">tiny zooplankton</a>. The whales need to find large, dense patches of zooplankton at appropriate water depths in order to feed. Altering waves, tides and currents in ways that affect where their prey are located could affect whale feeding or cause the whales to change foraging habitats. </p>
<p>We concluded that it is critical to consistently monitor right whales and their prey within and outside the region, because we don’t know whether wind development will cause an increase, a decrease or no change to their zooplankton prey. Consistent monitoring will allow managers to mitigate potential negative impacts on the whales.</p>
<p>Researchers will need to collect data during all phases of wind farm construction and operation and develop robust models to determine whether wind farms will affect prey availability for right whales in the study area. Even once they do this research, it will still be difficult to isolate potential impacts from wind farms. </p>
<p>There is a tremendous amount of both natural and human-driven variability and change in this region, including tides, seasonal changes in water temperature and long-term ocean warming driven by climate change. <a href="https://doi.org/10.1002/lno.12242">Climate-driven shifts in prey in distant regions</a>, such as the <a href="https://www.britannica.com/place/Bay-of-Fundy">Bay of Fundy</a> or the <a href="https://www.britannica.com/place/Gulf-of-Saint-Lawrence">Gulf of St. Lawrence</a>, may also change how right whales use the Nantucket Shoals region. </p>
<p>Development of the first wind energy farms in the Nantucket Shoals region is a valuable opportunity to better understand hydrodynamic impacts of turbines on marine ecosystems. We expect that it will help guide future development of wind farms along the U.S. East Coast. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing offshore wind energy potential along U.S. coastlines." src="https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=355&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=355&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=355&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=446&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=446&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558703/original/file-20231109-29-vwzt46.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=446&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 2022 assessment by the National Renewable Energy Laboratory estimated that fixed-bottom and floating offshore wind turbines could generate enough energy to cover three times the annual electricity consumption in the U.S.</span>
<span class="attribution"><a class="source" href="https://www.nrel.gov/wind/offshore-resource.html">NREL</a></span>
</figcaption>
</figure>
<h2>What are the most important knowledge gaps?</h2>
<p>Few studies have been done to understand hydrodynamics around wind energy turbines, and those that exist focus on European offshore wind farms in the North Sea, where conditions are different from Nantucket Shoals. Large turbines of the size planned for the Nantucket Shoals region have not been built yet in U.S. waters. </p>
<p>Researchers have tried to model the hydrodynamic impacts of turbines, but their results don’t always agree with each other. There’s a need for more work to compare different types of models with each other, and with actual observations in the ocean, to make sure that they represent key processes like tides, stratification, turbulence and drag correctly. </p>
<p>The most accurate outputs will likely come from using a range of models. Oceanographers might start with models that predict what happens as water moves past a single turbine. These results then would inform models that predict the effects of an entire wind farm. Then results from wind farm-scale models would be incorporated into models that predict regional ocean circulation.</p>
<p>There are also a lot of knowledge gaps on the biology side, including questions about what species of zooplankton are in the Nantucket Shoals region, where they come from and what makes them aggregate into patches that are dense enough for right whales to eat. Right whale feeding in the Nantucket Shoals region isn’t well understood, so scientists need more observations to determine which zooplankton types are targeted by right whales and where and when the whales feed.</p>
<h2>Does the report call for slowing offshore wind development until these questions are answered?</h2>
<p>No, and we were not asked to provide recommendations for how the wind industry should proceed with construction. </p>
<p>Nantucket Shoals is one of many regions where large-scale wind farms will be built in U.S. waters over the coming decades. Our committee advised federal regulators and other relevant organizations to conduct observational and modeling research to better understand hydrodynamic and ecological processes before, during and after wind farm construction. These studies will be critical for understanding and addressing environmental impacts from offshore wind farm development.</p>
<p><em>Richard Merrick, former chief science adviser and director of scientific programs at National Oceanic and Atmospheric Administration Fisheries, and Kelly Oskvig, National Academies of Sciences, Engineering, and Medicine director of the study described here, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/216330/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erin L. Meyer-Gutbrod receives funding from the Bureau of Ocean Energy Management. She serves as a volunteer on the Marine Mammal Subcommittee of the Regional Wildlife Science Collaborative for Offshore Wind.</span></em></p><p class="fine-print"><em><span>Douglas Nowacek receives funding from the U.S. Department of Energy and the Bureau of Ocean Energy Management.</span></em></p><p class="fine-print"><em><span>Eileen E. Hofmann receives funding from the Bureau of Ocean Energy Management. </span></em></p><p class="fine-print"><em><span>Josh Kohut receives funding from the U.S. Department of Energy. He serves as a volunteer member of the board of directors for the Marine Technology Society. </span></em></p>
A recent study focusing on how offshore wind farms in Massachusetts waters could affect endangered right whales does not call for slowing the projects, but says monitoring will be critical.
Erin L. Meyer-Gutbrod, Assistant Professor of Earth, Ocean & Environment, University of South Carolina
Douglas Nowacek, Professor of Conservation Technology in Environment and Engineering, Duke University
Eileen E. Hofmann, Professor of Oceanography, Old Dominion University
Josh Kohut, Professor of Marine and Coastal Sciences, Rutgers University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/214215
2023-11-06T05:39:38Z
2023-11-06T05:39:38Z
Fieldwork can be challenging for female scientists. Here are 5 ways to make it better
<figure><img src="https://images.theconversation.com/files/555493/original/file-20231024-23-98o1fy.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5851%2C3818&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Merla, Shutterstock</span></span></figcaption></figure><p>Women coastal scientists face multiple barriers to getting into the field for research. These include negative perceptions of their physical capabilities, not being included in trips, caring responsibilities at home and a lack of field facilities for women. Even if women clear these barriers, the experience can be challenging. </p>
<p>This is a problem because fieldwork is crucial for gathering data, inspiring emerging scientists, developing skills, expanding networks and participating in collaborative research. </p>
<p><a href="https://doi.org/10.1017/cft.2023.26">Our recent study</a> revisited an international survey of 314 coastal scientists that revealed broad <a href="https://theconversation.com/gender-inequalities-in-science-wont-self-correct-its-time-for-action-99452">perceptions and experiences of gender inequality</a> in coastal sciences. We offer five ways to improve the fieldwork experience for women. </p>
<p>Our collective experience of more than 70 years as active coastal scientists suggests women face ongoing problems when they go to the field. Against a global backdrop of the #MeToo movement, the <a href="https://www.pictureascientist.com/">Picture a Scientist</a> documentary and media coverage about <a href="https://www.nature.com/articles/d41586-022-00097-4">incidents of sexual harassment</a> in the field, conversations between fieldworkers and research managers about behaviour and policy change are needed. </p>
<figure class="align-center ">
<img alt="A collage of photos showing female fieldworkers operating equipment, carrying gear and fixing engines" src="https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555495/original/file-20231024-21-prd8yo.png?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">Disrupting the narrative: Women fieldworkers operating equipment, carrying gear and fixing engines.</span>
<span class="attribution"><span class="source">Women in Coastal Geosciences and Engineering network</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sexual-harassment-impacts-university-staff-our-research-shows-how-211996">Sexual harassment impacts university staff – our research shows how</a>
</strong>
</em>
</p>
<hr>
<h2>Our research: what we did and what we found</h2>
<p>In 2016, we surveyed both male and female scientists about their experiences of gender equality in coastal sciences during an international symposium in Sydney and afterwards online.</p>
<p>From 314 responses, 113 respondents (36%) provided examples of gender inequality they had either directly experienced or observed while working in coastal sciences. About half of these were related to fieldwork.</p>
<p>Our <a href="https://doi.org/10.1017/cft.2023.26">recent paper</a> in the journal Coastal Futures revisits the survey results to further unpack fieldwork issues that continue to surface among the younger generation of female coastal scientists whom we supervise in our jobs. Many of those younger women don’t know how to address these issues.</p>
<p>The paper includes direct quotes from 18 survey respondents describing their experiences. One woman, a mid-career university researcher, said:</p>
<blockquote>
<p>As I fill in this survey, the corridor of the building I work in is lined with empty offices. My colleagues are out on boats doing fieldwork. I have a passion for coastal science. That’s why I’m working in a university. But I have a disproportionately large share of administrative, pastoral and governance duties that keep me from engaging in my passion. I’m about to go to a committee meeting of women, doing women’s work (reviewing teaching offerings). Inequality is alive and well in my workplace! </p>
</blockquote>
<p>Collectively, the responses highlight barriers to fieldwork participation and challenges in the field, such as sexual harassment and abuse.</p>
<h2>A pressing issue, on and off campus</h2>
<p>Universities have recently been <a href="https://www.theguardian.com/australia-news/2023/sep/14/universities-criticised-for-failed-response-after-report-details-extent-of-sexual-violence-on-campuses">criticised for failing to respond</a> to sexual violence on campus. But women employed by universities working off campus – at field sites – can be even more vulnerable. </p>
<p>The social boundaries that characterise day-to-day working life in the office and the laboratory are reconfigured on boats or in field camps. Personal space is reduced. Fieldworkers can be required to sleep in close proximity to one another, potentially putting women in vulnerable situations.</p>
<p>As this female early-career university researcher wrote:</p>
<blockquote>
<p>Sometimes women are ‘advised’ to avoid fieldwork for security reasons. Or [we] are considered weak, or we are threatened by rape for being with a lot of men.</p>
</blockquote>
<p><a href="https://tos.org/oceanography/article/women-in-oceanography-continuing-challenges">Women working on boats</a> commonly face inadequate facilities at sea for toileting, menstruation and managing lactation. Some women said they were “not allowed to join research vessels” or “prevented from [joining] research in the field because of gender”. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1579235099224473600"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/photos-from-the-field-our-voyage-investigating-australias-submarine-landslides-and-deep-marine-canyons-184839">Photos from the field: our voyage investigating Australia's submarine landslides and deep-marine canyons</a>
</strong>
</em>
</p>
<hr>
<h2>Reminded of our personal experiences</h2>
<p>Just reading the survey responses was difficult for us. Tales of exclusion and discrimination were particularly confronting because they resonated with our own personal experiences. As one of us, Sarah Hamylton, recalls:</p>
<blockquote>
<p>I remember spending a hot day in my early 20s on a small boat taking measurements over a reef. I was the only female. When one of the four guys asked about needing the toilet, he was told to stand and relieve himself off the stern. I had to hold on, so I was desperate when we returned to the main ship in the afternoon. </p>
</blockquote>
<p>But that wasn’t the only challenge Hamylton encountered on that trip:</p>
<blockquote>
<p>We got back into port and the night before we departed to go home, I was woken by the drunken second officer banging on my cabin door asking for sex. The following year women were banned from attending this annual expedition because someone else had complained about sexual assault.</p>
</blockquote>
<h2>Gender stereotypes and discrimination</h2>
<p>Coastal fieldwork demands diverse physical skills such as boating, four-wheel driving, towing trailers, working with hand and power tools, moving heavy equipment, SCUBA diving and being comfortable swimming in the surf, in currents or underwater. </p>
<p>But our survey revealed roles on field trips – and therefore opportunities to learn and gain crucial field skills – are typically handed to men rather than women. Several respondents observed female students and staff being left out of field work for “not being strong enough” and “too weak to pick stuff up”. </p>
<p>Body exposure can also be an issue for women in the field. Close-fitting wetsuits and swimsuits can increase the likelihood of womens’ bodies being objectified by colleagues. Undertaking coastal fieldwork while menstruating can also be a concern.</p>
<p>Another of us, Ana Vila-Concejo, notes:</p>
<blockquote>
<p>Some scientific presentations show women in bikinis as a ‘beach modelling’ joke. Beyond self-consciousness, I have felt vulnerable wearing swimmers and exerting myself during fieldwork. Women students and volunteers have declined to participate in field experiments for this reason, particularly while menstruating. </p>
</blockquote>
<p>The issue of body exposure also sheds light on the interconnections between race, religion, class and sexuality, which can create overlapping and intersectional disadvantages for women. Vila-Concejo adds:</p>
<blockquote>
<p>I am old enough now that I don’t care anymore. I can afford a wetsuit, but many students and volunteers don’t have one. For some women, it isn’t socially or culturally acceptable to wear swimmers, or even to do fieldwork.</p>
</blockquote>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5S5uNqHzDRU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gender inequality in coastal sciences: Overcoming fieldwork challenges.</span></figcaption>
</figure>
<h2>Five suggestions for improvement</h2>
<p>To improve the fieldwork experience for women in coastal sciences, our research found the following behavioural and policy changes are needed: </p>
<ol>
<li><p><strong>publicise field role models and trailblazers</strong> to reshape public views of coastal scientists, increasing the visibility of female fieldworkers</p></li>
<li><p><strong>improve opportunities and capacity for women to undertake fieldwork</strong> to diversify field teams by identifying and addressing the intersecting disadvantages experienced by women</p></li>
<li><p><strong>establish field codes of conduct</strong> that outline acceptable standards of behaviour on field trips, what constitutes misconduct, sexual harassment and assault, how to make an anonymous complaint and disciplinary measures</p></li>
<li><p><strong>acknowledge the challenges women face in the field and provide support where possible</strong> in fieldwork briefings and address practical challenges for women in remote locations, including toileting and menstruation</p></li>
<li><p><strong>foster an enjoyable and supportive fieldwork culture</strong> that emphasises mutual respect, safety, inclusivity, and collegiality on every trip. </p></li>
</ol>
<p>These five simple steps will improve the experience of fieldwork for all concerned and ultimately benefit the advancement of science.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/gender-inequalities-in-science-wont-self-correct-its-time-for-action-99452">Gender inequalities in science won't self-correct: it's time for action</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214215/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah Hamylton receives funding from The Australian Research Council. She is affiliated with the Women in Coastal Geosciences and Engineering Network. </span></em></p><p class="fine-print"><em><span>Ana Vila Concejo receives funding from the Australian Research Council and other sources unrelated to the subject of this article. She is a founding member and former co-chair of the Women in Coastal Geoscience and Engineering Network.</span></em></p><p class="fine-print"><em><span>Hannah Power receives funding from the Australian Research Council, the NSW State Government State Emergency Management Program, the Queensland Resilience and Risk Reduction Fund, the New Zealand Ministry for Business, Innovation and Employment Endeavour Fund, and ship time from Australia's Marine National Facility. She is a member of the NSW Coastal Council and is affiliated with the Women in Coastal Geosciences and Engineering Network.</span></em></p><p class="fine-print"><em><span>Shari L Gallop works for Pattle Delamore Partners (PDP). She has an honorary lectureship with the University of Waikato. She is a founding member and former co-chair of the Women in Coastal Geoscience and Engineering Network.</span></em></p>
Growing awareness of sexual harassment and discrimination in the field prompted an international survey and research into potential solutions.
Sarah Hamylton, Associate professor, University of Wollongong
Ana Vila Concejo, Associate professor, University of Sydney
Hannah Power, Associate Professor in Coastal and Marine Science, University of Newcastle
Shari L Gallop, Service Leader - Coastal, University of Waikato
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/213678
2023-10-02T14:37:50Z
2023-10-02T14:37:50Z
Nigeria’s new blue economy ministry could harness marine resources - moving the focus away from oil
<p><em>Nigeria’s President Bola Ahmed Tinubu announced a new <a href="https://www.channelstv.com/2023/08/16/full-list-of-ministers-and-portfolios/">ministerial portfolio</a> in August: Marine and Blue Economy. This was <a href="https://dailypost.ng/2023/08/22/long-overdue-creation-of-marine-and-blue-economy-ministry-excites-stakeholders/">welcome news</a> as it renewed hope for economic development outside the oil sector. We asked marine sustainability and blue economy <a href="https://iucn.org/our-union/commissions/group/iucn-ceesp-governance-equity-and-rights-thematic-group">expert</a> Isa Olalekan Elegbede to explain how the ministry could benefit Nigeria.</em></p>
<h2>Why has Nigeria established a new ministry for the blue economy?</h2>
<p>The <a href="https://link.springer.com/referenceworkentry/10.1007/978-3-030-02006-4_401-1">blue economy</a> is the sustainable use of ocean and coastal resources for economic growth. It <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.00586/full">integrates environmental, social, economic and institutional objectives</a> into the use of marine resources. It <a href="https://blue-economy-observatory.ec.europa.eu/eu-blue-economy-sectors_en">includes a wide range of sectors and resources</a> related to oceans, seas, coasts and waterways.</p>
<p>The ocean economy supports <a href="https://www.oecd.org/ocean/topics/ocean-economy/">90% of global trade</a> and <a href="https://www.worldbank.org/en/topic/oceans-fisheries-and-coastal-economies">provides millions of jobs</a>. It includes shipping, tourism and offshore energy <a href="https://www.weforum.org/agenda/2020/06/human-impact-ocean-economy/">valued at US$24 trillion</a>. </p>
<p>Marine fisheries and reefs, sea grass and mangroves are worth US$6.9 trillion; trade and transport US$5.2 trillion; and coastline productivity and carbon absorption US$12.1 trillion. </p>
<p>Nigeria’s establishment of a Ministry of Marine and Blue Economy is a strategic move. I believe the ministry will tap the country’s rich marine resources as an element of the national economic framework. </p>
<p>Nigeria’s coastline <a href="https://fcwc-fish.org/other-news/nigerian-navy-at-64-a-sustained-fight-against-maritime-crimes">stretches</a> for 420 nautical miles and covers an exclusive economic zone of 200 nautical miles. Its maritime interests span the Gulf of Guinea, covering roughly 574,800 square nautical miles with a 2,874 nautical mile coastline.</p>
<p>Marine resources can be exploited to create jobs and transform Nigeria into a <a href="https://venturesafrica.com/now-that-nigeria-has-created-a-ministry-of-marine-and-blue-economy/">leader in sustainable marine activities</a>. It will help diversify the country’s oil-based economy as well. <a href="https://www.rvo.nl/sites/default/files/2021/07/Blue-Bio-Economy-in-Norway.pdf">Norway</a> is an example of how this has been done successfully.</p>
<h2>What four areas should the ministry focus on?</h2>
<p>Nigeria hopes to generate over <a href="https://punchng.com/what-you-need-to-know-about-ministry-of-marine-and-blue-economy/">US$1.5 trillion annually</a> from exploiting its marine resources. To achieve this, the ministry should do the following:</p>
<ul>
<li><p>Create an inclusive committee for effective collaboration among stakeholders and partners. The committee should include scientists, NGOs, youth and traditional communities. Indigenous peoples, persons with disabilities, and the relevant <a href="https://www.legit.ng/politics/1549451-list-ministries-created-by-president-tinubu-ministers/">federal government agencies</a> should not be left out. The committee should advance beyond the scope of the Expanded Committee on Sustainable Blue Economy in Nigeria inaugurated by the former president Muhammadu Buhari.</p></li>
<li><p>Integrate sustainability into policies and strategies. Policies should prioritise sustainable marine resource use. Strategies should focus on sustainable and ethical harvesting, trading, extraction and tourism. Blue economy personnel, unemployed youths and women should be trained. Improved programmes would foster sustainable practices and raise the sector’s contribution to the country’s gross domestic product. </p></li>
<li><p>Sustain investment in ports, transport systems and storage facilities. The same should apply to research and technology. Aquaculture, offshore energy and marine biotechnology should be advanced to increase efficiency and sustainability. Additionally, remote coastal communities should have <a href="https://www.energy.gov/eere/water/marine-energy-blue-economy">access</a> to resilient and blue renewable energy sources and systems to enhance protection of coastal and ocean resources.</p></li>
<li><p>Check mismanagement. To ensure a sustainable future for all, the government should protect coastal and marine ecosystems. Mismanagement could destabilise the delicate balance of these ecosystems. This is crucial, considering the <a href="https://enveurope.springeropen.com/articles/10.1186/s12302-021-00502-1">intricate relationship between the blue economy and marine habitats</a>. Neglect puts fish resources at risk and endangers vital sectors like maritime transport, energy and fishing. Cooperation and commitment to stewardship are therefore imperative to maintaining the health and productivity of the oceans.</p></li>
</ul>
<h2>What benefits will Nigerians feel if these steps are taken?</h2>
<p>Oil is a key revenue source for the country. But it has led to major environmental problems. Harnessing the blue economy could be a game changer for Nigeria.</p>
<p>First, it could create jobs and generate income from fisheries, aquaculture, tourism, shipping and renewable energy. </p>
<p>Second, a blue economy could mitigate environmental damage as it enables the restoration of marine ecosystems. Unlike oil, fisheries are renewable. Nigeria’s oil-rich Niger Delta has experienced severe environmental harm. A shift to greener energy supplies could make a massive difference.</p>
<p>Third, it creates the opportunity to grow the tourism sector. Seychelles and Mauritius are examples of countries that earn foreign exchange from marine exports and tourism. </p>
<p>Fourth, it could help attract investment to Nigeria’s marine infrastructure, fisheries and technology. </p>
<p>Fifth, it could help decrease regional and social inequalities in coastal communities. </p>
<p>Finally, investment in the blue economy could encourage marine biology, oceanography and marine technology research. This could, in turn, lead to global innovations. </p>
<p>Despite competition from more experienced countries in the marine industry, the blue economy offers Nigeria significant potential. Strategic planning, global partnerships and investment can make it a reality.</p><img src="https://counter.theconversation.com/content/213678/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Isa O Elegbede is presently affiliated with the Lagos State University and with many international and local NGOs, such as Geo Blue Planet, IUCN/CEESP/TGER; he is also the president of Sayne Development Foundation and Executive director of Pearlrose Foundation. He has received a fellowship grant from Ocean Frontier institute (OFI) in Canada and several international organisations in the past.</span></em></p>
Nigeria’s new marine and blue economy ministry has promise but it must be well run.
Isa Olalekan Elegbede, Lecturer, Brandenburg University of Technology Cottbus-Senftenberg
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/211207
2023-09-07T20:01:57Z
2023-09-07T20:01:57Z
Whales stop singing and rock lobsters lose their balance: how seismic surveys can harm marine life
<figure><img src="https://images.theconversation.com/files/546675/original/file-20230906-22-wgw02j.jpg?ixlib=rb-1.1.0&rect=53%2C33%2C4439%2C2957&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/whale-half-air-315070277">jamesteohart, Shutterstock</a></span></figcaption></figure><p>Woodside Energy this week announced it <a href="https://www.afr.com/companies/energy/woodside-to-start-scarborough-seismic-despite-legal-stoush-20230906-p5e2ff">would start seismic testing</a> for its Scarborough gas project off Australia’s west coast, before <a href="https://www.watoday.com.au/national/western-australia/woodside-vows-to-halt-seismic-testing-as-scarborough-row-escalates-20230907-p5e2rw.html">reversing the decision</a> in the face of a legal challenge from Traditional Owners. </p>
<p>Seismic testing is highly controversial in marine environments. The federal regulator (the National Offshore Petroleum Safety and Environmental Management Authority) is currently examining a proposal for seismic testing <a href="https://docs.nopsema.gov.au/A952201">in the Otway Basin</a> in Bass Strait, which conservationists say has attracted <a href="https://www.marineconservation.org.au/30000-submissions-over-seismic-blasting-between-otway-coast-nw-tasmania/">more than 30,000 public submissions</a>. </p>
<p>Seismic testing <a href="https://www.nationaltribune.com.au/pep11-is-back-gas-oil-drilling-to-start-off-nsw/">is also mooted</a> as part of the “PEP11” (Petroleum Exploration Permit 11) off the coast of New South Wales, from Manly to Newcastle. </p>
<p>As marine biologists with research expertise in this field, here we give a roundup of the latest evidence on the effects of seismic surveys. It shows there are many potential harms to marine life, and many unanswered questions. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/o3-BxUE1iOg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Australian Marine Conservation Society wants to stop seismic surveys.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/underwater-noise-is-a-threat-to-marine-life-197432">Underwater noise is a threat to marine life</a>
</strong>
</em>
</p>
<hr>
<h2>What are seismic surveys?</h2>
<p>Marine seismic surveys are used to search for <a href="https://www.industry.gov.au/mining-oil-and-gas/oil-and-gas/offshore-oil-and-gas/offshore-oil-and-gas-exploration-and-development-requirements">oil and gas</a>, <a href="https://www.minister.industry.gov.au/ministers/king/media-releases/new-offshore-greenhouse-gas-storage-acreage-help-cut-emissions">places to stash greenhouse gases</a>, and potential locations for <a href="https://www.openaccessgovernment.org/offshore-wind-farm-construction/78913/">wind farms</a>. </p>
<p>The surveys use air guns to generate sound signals. These sound signals are intense (loud, at high decibel levels) and “impulsive” (sharp, like a balloon popping). In the open ocean, sound waves can be detected <a href="https://pubs.aip.org/asa/jasa/article/131/2/1102/917139">thousands of kilometres</a> from the source. </p>
<p>The sound can penetrate more than ten kilometres into the earth beneath the seafloor. The way the signals reflect off different layers of the seabed can identify geological structures, including those that contain mineral deposits such as oil and gas. The sound signals bounce back to acoustic receivers (hydrophones) towed behind the survey vessel on cables known as streamers.</p>
<p>During a survey, sound signals are generated every four to ten seconds, 24 hours a day, seven days a week. Surveys can last for weeks or months, and cover thousands of square kilometres of ocean. The proposal to study the Otway Basin, for example, covers 45,000 square km. </p>
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<h2>Seismic surveys and marine life</h2>
<p>The ability to fully examine the effects of seismic surveys in mammals is limited, because invasive methods are not logistically possible or ethically acceptable. </p>
<p>But there is a <a href="https://www.google.com.au/books/edition/Marine_Mammals_and_Noise/OIWmaG906jgC?hl=en">long history</a> of research on whales and dolphins, given their reliance on sound to communicate, find food and navigate. </p>
<p><a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/130286">Observations of marine mammals</a> show intense sound signals such as those from seismic surveys can affect hearing ability, either temporarily or permanently, depending on the intensity, range and duration of exposure. </p>
<p>Noise pollution can mask communications, causing whales either to <a href="https://pubs.aip.org/asa/jasa/article/147/3/2061/997280">sing more loudly</a> or to <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mms.12001">stop singing</a> altogether, which can affect social structure and interaction. Seismic surveys can also alter the presence and abundance of marine mammal <a href="https://www.ingentaconnect.com/content/mts/mtsj/2003/00000037/00000004/art00003#">prey</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/hXTcnd1pXBU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Offshore Seismic Surveys at Woodside.</span></figcaption>
</figure>
<h2>What about fish?</h2>
<p>Fish also show a range of responses to seismic testing. Some fish exhibit physical damage to <a href="https://pubs.aip.org/asa/jasa/article/113/1/638/548740/High-intensity-anthropogenic-sound-damages-fish">hearing organs</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0144860915000503">signs of stress</a>. </p>
<p>Fish behaviour may also change. Some leave regular feeding or breeding areas, which raises concerns over effects to fishing grounds or impacts on important prey species. It’s also uncertain whether the fish will be able to find suitable alternative habitats if they are displaced in the long term.</p>
<p>Others may “<a href="https://academic.oup.com/conphys/article/7/1/coz020/5490268?login=true">habituate</a>” or become accustomed to exposure, raising the risk of more extensive damage by spending more time in the survey area. </p>
<h2>Scallops, lobsters and plankton</h2>
<p>Despite invertebrates making up around <a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.690704/full">92% of marine species</a>, the impact of marine noise on these creatures has only recently been studied. This <a href="https://www.frontiersin.org/articles/10.3389/fmars.2023.1129057/">has shown</a> a potential for harm. </p>
<p>In the valuable southern rock lobster fishery, off the coasts of Victoria, South Australia and Tasmania, seismic air gun exposure <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2019.1424">damaged the sensory organ</a> that provides a sense of gravity and balance, similar to the human inner ear. Affected lobsters also had impaired ability to right themselves when placed upside down, a reflex that underpins important behaviours such as escaping predators. </p>
<p>Scallops showed more <a href="https://www.pnas.org/doi/10.1073/pnas.1700564114">severe impacts</a>, with up to four times higher death rates and a range of other sub-lethal effects including altered behaviour, impaired physiology and a disrupted immune system. As this animal already suffers high levels of mortality naturally and due to fishery activity, this extra pressure could be of considerable concern. </p>
<p>Invertebrates also make up a large proportion of the <a href="https://www.imas.utas.edu.au/zooplankton/about/what-are-zooplankton">zooplankton</a> community, a broad group of very small animals carried by ocean currents. They are food for a wide range of marine life, from other zooplankton to small fish and whales. </p>
<p>In the <a href="https://www.nature.com/articles/s41559-017-0195">first experimental exposure</a> to a seismic air gun, a large proportion of zooplankton died. Overall abundance decreased significantly, at distances up to 1.2km from the air gun. </p>
<p>Confirming this result, <a href="https://www.sciencedirect.com/science/article/pii/S0269749123004712">another recent study</a> of zooplankton found exposure to seismic air guns 50 metres away resulted in increased mortality immediately after exposure. The plankton continued to die off or suffer impaired development for several days. These effects, particularly in the case of exposure that is repeated over the course of months within a single area, have the potential to severely impact the plankton populations that underpin marine food webs.</p>
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<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australian-humpback-whales-are-singing-less-and-fighting-more-should-we-be-worried-200062">Australian humpback whales are singing less and fighting more. Should we be worried?</a>
</strong>
</em>
</p>
<hr>
<h2>Difficulties in predicting impacts</h2>
<p>While the handful of available studies shows exposure to seismic surveys can harm animals, our ability to understand or predict what happens in the wild is still very limited.</p>
<p>Part of the problem is conflicting results. For example, in one case, seismic survey exposure had no impact on the <a href="https://www.pnas.org/doi/10.1073/pnas.2100869118">types of fish found in an area or their behaviour</a>. And a separate study of <a href="https://www.sciencedirect.com/science/article/pii/S0025326X17309128">scallops</a> found no mortality after seismic exposure. These studies conflict with the results we described earlier, which happens commonly in science and highlights the need for ever more detailed research.</p>
<p>Only a few animal species have so far been investigated, making it hard to tell how other animals might be affected by seismic testing. There are also limitations to the methods of studies that reduce our ability to understand the real-world impacts, such as housing animals in captivity after exposure. </p>
<p>Sound behaves very differently in water than in air. Water is more dense, allowing sound to travel faster, farther and with less of a drop in intensity. Comparisons between the “loudness” of sounds in air and water <a href="https://oceanexplorer.noaa.gov/explorations/sound01/background/acoustics/acoustics.html">are not straightforward</a>. </p>
<p>While mounting evidence shows seismic surveys can harm a range of marine animals, there is so much still to learn. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-has-introduced-a-new-bill-that-will-allow-us-to-ship-carbon-emissions-overseas-heres-why-thats-not-a-great-idea-208456">Australia has introduced a new bill that will allow us to ship carbon emissions overseas. Here's why that's not a great idea</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/211207/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Day has received funding and/or research contributions from the Australian Government through the Fisheries Research and Development Corporation, Beach Energy, CGG, ConocoPhillips, Origin Energy, the CarbonNet Project, the Victorian Department of Economic Development, Jobs, Transport and Resources.</span></em></p><p class="fine-print"><em><span>Jayson Semmens has received funding and/or research contributions from the Australian Government through the Fisheries Research and Development Corporation, Beach Energy, CGG, ConocoPhillips, Origin Energy, the CarbonNet Project, the Victorian Department of Economic Development, Jobs, Transport and Resources.</span></em></p><p class="fine-print"><em><span>Robert McCauley receives funding from industry and Government to study impacts of seismic on marine fauna, which over his career includes: Fisheries Research and Development Corporation (FRDC); Beach Energy; CGG; University of Tasmania; Australian Institute of Marine Science; Australian Petroleum Production Exploration Association (APPEA); Bureau Offshore Energy and Minerals (BOEM, USA); Joint Industry Program (JIP); Woodside Energy; Origin Energy; Santos; Apache Energy (now Quadrant); and Roc Oil.</span></em></p>
Mounting evidence shows seismic surveys can harm a range of marine animals.
Ryan Day, Senior research fellow, University of Tasmania
Jayson Semmens, Professor, Sustainable Marine Research Collaboration, University of Tasmania
Robert McCauley, Professor at the Centre for Marine Science and Technology, Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/211887
2023-08-23T18:00:14Z
2023-08-23T18:00:14Z
Secrets of the Octopus Garden: Moms nest at thermal springs to give their young the best chance for survival
<figure><img src="https://images.theconversation.com/files/544085/original/file-20230822-27-tpp2pi.jpg?ixlib=rb-1.1.0&rect=330%2C14%2C1549%2C1063&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Female pearl octopus nest at the Octopus Garden off California.</span> <span class="attribution"><a class="source" href="https://www.mbari.org/about/for-media/">Credit: © 2019 MBARI</a></span></figcaption></figure><p>Two miles below the ocean surface off Monterey, California, warm water percolates from the seafloor at the base of an underwater mountain. It’s a magical place, especially if you’re an octopus. </p>
<p>In 2018, one of us, <a href="https://scholar.google.ca/citations?user=Cq1iuicAAAAJ">Amanda Kahn</a>, was aboard the research vessel E/V Nautilus when scientists discovered the “Octopus Garden.” Thousands of pearl octopuses (<em>Muusoctopus robustus</em>) were curled up into individual balls in lines and clumps. As Nautilus Live <a href="https://youtu.be/RHR70lVy79Y">streamed the expedition</a> online, the world got to share the excitement of the discovery.</p>
<p>We now know why these amazing creatures gather at this and other underwater warm springs.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/zEXUOPkQPo8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientists with the Monterey Bay Aquarium Research Institute take viewers on a journey to Davidson Seamount in a video narrated by Jim Barry, an author of this article. Credit: © MBARI.</span></figcaption>
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<p>In a <a href="https://www.science.org/doi/10.1126/sciadv.adg3247">new study</a> involving scientists from several fields, we explain why octopuses migrate to the Octopus Garden. It’s both a mating site and a nursery where newborn octopuses develop faster than expected, giving them the best shot at survival in the deep, cold sea.</p>
<h2>Life in the Octopus Garden</h2>
<p>Female octopuses seek out rocky cracks and crevices <a href="https://www.science.org/doi/10.1126/sciadv.adg3247">where warm water seeps</a> from the rocks. There, they vigilantly guard their broods. Subsisting off their energy reserves alone, these mothers will never eat again. Like most cephalopods, they make the ultimate sacrifice for their offspring and die after their eggs hatch.</p>
<p>The Octopus Garden, at the base of <a href="https://montereybay.noaa.gov/research/dsmz/welcome.html">Davidson Seamount</a> about 80 miles (130 kilometers) southwest of Monterey, California, is the largest of a handful of octopus nurseries recently discovered in the Eastern Pacific. Many have been found near hydrothermal springs where warm water seeps from the seafloor.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing Monterey Bay National Marine Sanctuary and the location of the Octopus Garden near Davidson Seamount, an inactive volcano off the Central California coast, at a depth of approximately 2 miles (3,200 meters)." src="https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544086/original/file-20230822-27-c2nbz5.jpg?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"></a>
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<span class="caption">The Octopus Garden is about 2 miles deep near Davidson Seamount, an inactive volcano off the Central California coast. It is inside the Monterey Bay National Marine Sanctuary.</span>
<span class="attribution"><a class="source" href="https://www.mbari.org/">Illustration by Madeline Go/MBARI, basemap created via ArcGIS Online, sources: Esri, USGS | Esri, GEBCO, DeLorme, NaturalVue | California State Parks, Esri, HERE, Garmin, SafeGraph, FAO, METI/NASA, USGS, Bureau of Land Management, EPA, NPS</a></span>
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<p>We wanted to know what makes these environments so appealing for nesting octopuses.</p>
<p>To solve this mystery, we assembled geologists, biologists and engineers. Using <a href="https://www.mbari.org/">Monterey Bay Aquarium Research Institute</a>’s deep-sea <a href="https://www.mbari.org/technology/rov-doc-ricketts/">robots</a> and <a href="https://www.mbari.org/project/low-altitude-survey-system/">sensors</a>, we studied and mapped the Octopus Garden during several visits over three years to examine the links between thermal springs and breeding success for pearl octopuses. We found nearly 6,000 nests in a 6-acre (2.5-hectare) area, suggesting more than 20,000 octopuses occupy this site.</p>
<p>A time-lapse camera that kept watch over a group of nesting mothers for six months opened a window into the <a href="https://www.youtube.com/watch?v=zEXUOPkQPo8">dynamic life in the Octopus Garden</a>.</p>
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<a href="https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo taken underwater shows a female octopus in a depression in the surface with her tentacles around several oblong eggs." src="https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544087/original/file-20230822-29-xqz938.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"></a>
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<span class="caption">A female pearl octopus brooding her eggs at the Octopus Garden.</span>
<span class="attribution"><a class="source" href="https://www.mbari.org/about/for-media/">Credit: © 2020 MBARI</a></span>
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<p>We witnessed male octopuses approaching and mating with females. We cheered for the successful emergence of hatchlings, which looked like translucent miniatures of their parents. And we mourned the deaths of mothers and their broods.</p>
<p>When a nest became empty, it was quickly filled by a different octopus mother. We saw that nothing went to waste at the Octopus Garden. Dead octopesus provided a vital food source for a host of scavengers, like sea anemones and snails.</p>
<h2>Warmer water speeds up embryo development</h2>
<p>A new generation of octopuses must overcome at least two hurdles before hatching.</p>
<p>First, they must develop from egg to hatchling. They start as opaque, sausage-shaped eggs cemented to the rocks. Over time, tiny black eyes, then eight little arms grow visible through the egg capsule. Second, crucially, <a href="https://doi.org/10.1016/j.aquaculture.2013.12.039">they must not succumb to external threats</a>, including predators, injuries and infections. The longer the incubation period, the greater the risk that an embryo might not survive to hatch.</p>
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<a href="https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo shows dozens of octopuses forming a line and clumps where heat seeps out." src="https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=483&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=483&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=483&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=607&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=607&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544096/original/file-20230822-15-ebr25z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=607&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 portion of a photomosaic produced following surveys of the Octopus Garden with MBARI’s remotely operated vehicle Doc Ricketts and the Low-Altitude Survey System sensor suite from the Seafloor Mapping Lab at Monterey Bay Aquarium Research Institute, or MBARI. The photo allowed researchers to count nests and estimate the total.</span>
<span class="attribution"><a class="source" href="https://www.mbari.org/about/for-media/">Credit: © 2022 MBARI</a></span>
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<p>For octopus species living in warm, shallow waters, <a href="https://doi.org/10.3354/meps12749">brood periods are only days to weeks long</a>. But a very different scenario plays out in the abyss. Near-freezing temperatures dramatically slow metabolic processes in coldblooded animals like octopuses. The <a href="https://doi.org/10.1371/journal.pone.0103437">longest-known brood period for any animal</a> actually comes from another deep-sea octopus species, <em>Graneledone pacifica</em>, with a mother tending her nest for a remarkable 4½ years. An octopus nursery for this species <a href="https://www.oceannetworks.ca/expeditions/northeast-pacific-deep-sea-expedition/">was recently discovered off the west coast of Canada</a>.</p>
<p>At Davidson Seamount, where ambient water temperatures are 35 degrees Fahrenheit (1.6 degrees Celsius), we would expect pearl octopus embryos to <a href="https://www.science.org/doi/10.1126/sciadv.adg3247">take five to 10 years</a>, or possibly longer, to develop. Such an extended brooding period would be the longest known for any animal, exposing an embryo to exceptional risks.</p>
<p>Instead, temperature and oxygen sensors we were able to slip inside octopus nests documented a much warmer microenvironment around the eggs. On average, the temperature inside octopus nests was about 41 F (5.1 C), considerably warmer than the surrounding waters. We predicted that octopus embryos would develop faster in this warmer water.</p>
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<a href="https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A female pearl octopus brooding her eggs at the Octopus Garden." src="https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544095/original/file-20230822-14419-19c1pz.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"></a>
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<span class="caption">Each octopus has distinctive markings that scientists quickly learned to identify.</span>
<span class="attribution"><a class="source" href="https://www.mbari.org/about/for-media/">Credit: © 2022 MBARI</a></span>
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<p>Distinctive marks and scars helped us identify individual mothers. Over repeat visits we tracked the development of their brood. Although we did expect faster growth in the warm water, we were stunned to find that eggs hatched in less than two years. Nesting in thermal springs clearly gives pearl octopuses a boost.</p>
<p>But nesting in thermal springs is a potentially risky strategy. Once eggs are laid, they’re <a href="https://doi.org/10.1098/rspb.1975.0005">cemented to the rock</a>. We know little of the thermal tolerance of pearl octopuses or their embryos, but even a short exposure to overly warm waters could be lethal to developing embryos, wiping out any hope of successful reproduction for that mother. Indeed, one of the first recorded deep-sea octopus nurseries may have <a href="https://doi.org/10.1016/j.dsr.2018.03.011">experienced unpredictable fluid flow</a>.</p>
<h2>Nurseries highlight risks to seafloor habitat</h2>
<p>The thermal springs at the Octopus Garden are part of a <a href="https://doi.org/10.1029/2018GC007933">ridge flank hydrothermal system</a>. Here, water percolating beneath the seafloor picks up heat from Earth’s mantle before it’s channeled out from volcanic rock outcrops like Davidson Seamount. These systems have become an emerging focus in seafloor geology, though only a few have been discovered so far.</p>
<p>Unlike hydrothermal vents, which form at ridge crests and belch plumes of hot water that are detectable hundreds of meters above the bottom, thermal springs on ridge flanks are cryptic. These springs seep warm water that dissipates only meters above the bottom, making them exceedingly difficult to find and only visible by a slight shimmer in the water.</p>
<p>Our yearlong recordings from thermal springs at the Octopus Garden demonstrate these may be stable environments, with the potential to release warm fluids for thousands of years. Such stability benefits not only pearl octopus, but also the community of life that thrives alongside the nesting mothers.</p>
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<a href="https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo shows an octopus using its long arms to move across the seafloor." src="https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544097/original/file-20230822-20-d5s58a.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"></a>
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<span class="caption">A male octopus walks through the Octopus Garden.</span>
<span class="attribution"><a class="source" href="https://www.mbari.org/about/for-media/">Credit: © 2019 MBARI</a></span>
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<p>The recent discoveries of <a href="https://schmidtocean.org/scientists-discover-new-deep-sea-octopus-nurseries-in-costa-rica/">octopus nurseries off the Pacific coast of Costa Rica</a>, also near hydrothermal springs, suggests these areas may be more common than previously thought. It also highlights that hydrothermal springs may be vital biological hot spots.</p>
<p>The deep sea is the largest living space on Earth, and that expansive size can hide the importance of localized hot spots like these. Davidson Seamount and its Octopus Garden are protected as part of <a href="https://montereybay.noaa.gov">Monterey Bay National Marine Sanctuary</a>, but many more biological treasures like thermal springs may be at risk, especially as <a href="https://theconversation.com/deep-seabed-mining-plans-pit-renewable-energy-demand-against-ocean-life-in-a-largely-unexplored-frontier-193273">deep-seabed mining</a> proposes to scrape large <a href="https://doi.org/10.1016/j.marpol.2022.105006">understudied swaths of seafloor</a>. We hope the octopus mothers we’ve met at this nursery inspire everyone to rethink stewardship for the yet-undiscovered hidden gems that may be lost.</p><img src="https://counter.theconversation.com/content/211887/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jim Barry receives funding from NOAA.</span></em></p><p class="fine-print"><em><span>Amanda Kahn does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Thousands of pearl octopuses were discovered in 2018 lining thermal vents near a deep-sea volcano. Researchers now know why octopus moms gather there.
Amanda Kahn, Assistant Professor of Invertebrate Ecology at Moss Landing Marine Laboratories, San José State University
Jim Barry, Marine Ecologist, MBARI, San José State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/209333
2023-07-30T20:08:25Z
2023-07-30T20:08:25Z
The secret lives of silky sharks: unveiling their whereabouts supports their protection
<figure><img src="https://images.theconversation.com/files/537312/original/file-20230713-21-uoy0fa.jpg?ixlib=rb-1.1.0&rect=11%2C5%2C1905%2C1072&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Marine Futures Lab</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Open ocean sharks are elusive and mysterious. They undertake vast journeys that span hundreds to thousands of kilometres across immense ocean basins. We know very little about the secret lives of ocean sharks, where they live and why they are there.</p>
<p>What we do know is sharks are immensely important to the natural systems in which they live. Over 450 million years of evolution have perfected their role as apex predators and they play vital roles in fish community regulation and nutrient cycling. Healthy ecosystems rely on healthy shark populations. </p>
<p>Sharks, numbering more than <a href="https://ocean.si.edu/ocean-life/sharks-rays/sharks">500 species</a>, are also among the most threatened groups of vertebrates (animals with backbones). After surviving five mass extinctions through geological time, sharks are now facing the greatest threat to their survival from industrial fishing. </p>
<p>Their elusive nature and the immensity of our oceans means sharks are difficult to study. Our limited knowledge is particularly problematic given their threatened status. A solid understanding of the distribution of oceanic sharks is fundamental to their protection and our <a href="https://link.springer.com/article/10.1007/s10641-023-01437-7">new research</a> provides valuable insights into the secret lives of these wide-ranging predators.</p>
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Read more:
<a href="https://theconversation.com/oceanic-sharks-and-rays-have-declined-by-71-since-1970-a-global-solution-is-needed-154102">Oceanic sharks and rays have declined by 71% since 1970 – a global solution is needed</a>
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<h2>Silky by name, silky by nature</h2>
<p><a href="https://www.fishbase.se/summary/Carcharhinus-falciformis.html">Silky sharks</a> (<em>Carcharhinus falciformis</em>), named for the silky-smooth feel of their skin, are emblematic of open ocean sharks. They are highly mobile, have long life-spans, and are slow to reproduce. They are found throughout tropical and sub-tropical waters.</p>
<p>Silky shark numbers have declined globally due to industrial-scale fishing. Targeted for their fins and meat, they are also frequently incidentally caught in tuna fisheries. In 2017 the International Union for the Conservation of Nature classified this species as <a href="https://www.iucnredlist.org/ja/species/39370/205782570">vulnerable</a> to extinction. Their trade is controlled under the Convention on International Trade in Endangered Species.</p>
<h2>What we did</h2>
<p><a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.649123/full">Baited remote underwater video systems</a>, or BRUVS for short, are used to document the wildlife of the open oceans. Armed with a pair of small action cameras and baited to attract predators, BRUVS are suspended at 10m depth and drift with ocean currents. Video analysts review the footage to identify, count and measure all observed animals.</p>
<p>BRUVS have previously revealed the <a href="https://www.thelondoneconomic.com/news/environment/sharks-and-marine-predators-need-to-live-1250km-from-humans-in-order-to-thrive-155182/">impact of human activity</a> on marine predator populations, the ecological value of offshore oil and gas platforms as <a href="https://particle.scitech.org.au/earth/offshore-rigs-and-their-boon-for-marine-life/">novel ecosystems</a>, and even that tunas use sharks to scratch their itches.</p>
<p>We deployed more than 1,000 BRUVS across the Atlantic, Pacific and Indian oceans between 2012-20 to record where silky sharks hang out and predict how many there are and how big they are.</p>
<figure class="align-center ">
<img alt="PhD candidate Andrea López onboard a boat deploys a baited remote underwater video systems rig" src="https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537231/original/file-20230713-27-4h4hjg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Baited remote underwater video systems, or BRUVS, are lightweight yet robust due to their carbon fibre design. Here PhD candidate Andrea López deploys a BRUVS rig.</span>
<span class="attribution"><span class="source">Blue Abacus</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-fishes-scratch-their-itches-it-turns-out-sharks-are-involved-192512">How do fishes scratch their itches? It turns out sharks are involved</a>
</strong>
</em>
</p>
<hr>
<h2>A love affair between silky sharks and seamounts</h2>
<p>Silky sharks love seamounts. The closer we sampled to seamounts, the more frequently we observed silky sharks, and in higher numbers. </p>
<p>Seamounts are huge underwater mountains that rise from depths of thousands of metres to pinnacles that summit from hundreds to just tens of metres below the surface. The best estimate predicts the occurrence of more than <a href="https://ucl.scienceopen.com/hosted-document?doi=10.14324/111.444/ucloe.000030">37,000 seamounts</a> worldwide.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=292&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=292&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=292&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=367&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=367&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537234/original/file-20230713-21-56laau.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=367&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There are more than 37,000 seamounts globally and the majority are unprotected.</span>
<span class="attribution"><span class="source">Data from Yesson et al. (2019)</span></span>
</figcaption>
</figure>
<p>Seamounts are often hotspots of marine biodiversity. They act as landmarks in the otherwise relatively featureless open ocean seascape. Seamounts provide feeding, breeding, and resting spots for ocean roamers such as sharks, tuna, and whales. Migratory wildlife also use seamounts as navigational beacons and as stepping stones along their trans-ocean journeys.</p>
<p>Our results also reveal the smallest silky sharks hang out closest to seamounts. Seamounts may provide a rich smorgasbord for these rapidly growing youngsters.</p>
<figure class="align-center ">
<img alt="A silky shark pup approaches the baited remote underwater video systems" src="https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537293/original/file-20230713-19-j8t5f7.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">This 68cm silky shark pup provides insights into the whereabouts of this rarely seen life stage.</span>
<span class="attribution"><span class="source">Marine Futures Lab</span></span>
</figcaption>
</figure>
<h2>A human footprint on silky sharks</h2>
<p>Humans are leaving their <a href="https://www.newscientist.com/article/dn13326-map-reveals-extent-of-human-damage-to-oceans/">heavy footprints</a> on much of the ocean and silky sharks are no exception. Silky shark numbers declined the closer we sampled to coastal ports. Only the most remote areas had high numbers of silky sharks.</p>
<p>Silky sharks close to ports and human populations were also smaller than those observed further away. Such patterns are consistent with fishing impacts as exploitation typically first removes the largest individuals from the population. Our results reflect those for other open ocean sharks: hammerhead, sandbar, tiger and whale sharks have all <a href="https://ncseagrant.ncsu.edu/coastwatch/current-issue/spring-2022/are-sharks-getting-smaller/">declined globally in numbers and size </a>.</p>
<p>The distribution of silky sharks exemplifies the pervasive and negative impacts of human activity on oceanic sharks more generally. It highlights the critical need for refuges in which these animals are protected from exploitation.</p>
<figure class="align-center ">
<img alt="Image of a shark with a hook and line in its mouth" src="https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=271&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=271&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=271&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537235/original/file-20230713-27-5zkdsr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Silky sharks are particularly vulnerable to longline fishing.</span>
<span class="attribution"><span class="source">Simon Baxter/WWF</span></span>
</figcaption>
</figure>
<h2>A path to protection</h2>
<p>The need for improved protection for oceanic wildlife is well-recognised and marine protected areas are a key tool to deliver this protection. In 2022, under the Convention on Biological Diversity, nearly every country in the world committed to <a href="https://www.rmg.co.uk/stories/our-ocean-our-planet/what-is-30x30-marine-protected-areas-ocean-2030">protect 30% of their oceans by 2030</a>. </p>
<p>In 2023, the <a href="https://www.bbc.com/news/science-environment-64815782">High Seas Treaty</a> was ratified by the 193 member states of the United Nations, paving the path towards strong and effective protection of the vast swaths of ocean beyond national jurisdiction. Given that less than <a href="https://mpatlas.org/">2.9% of our oceans</a> are currently highly protected, such opportunities are essential.</p>
<p>Our research provides clues on how best to harness these agreements to protect silky sharks and their open-ocean companions. If marine protected areas are going to work, they need to include areas that threatened wildlife inhabit. As seamounts are hotspots for silky sharks, they are a fitting focus for marine protected areas.</p>
<p>It has never been more important to protect sharks. We have never had as much knowledge to do so. We hope recent commitments to ocean protection will spur research to further unveil the secret lives of oceanic sharks and ensure their survival in the face of their greatest threat yet.</p><img src="https://counter.theconversation.com/content/209333/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica Meeuwig has received funding from the Ian Potter Foundation, the Bertarelli Foundation, and receives funding from National Geographic's Pristine Seas programme. </span></em></p><p class="fine-print"><em><span>Shona Murray 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>
Open ocean sharks are globally threatened with extinction. Knowing where they are helps us protect them. Here, new research into silky sharks reveals priorities for conservation.
Shona Murray, PhD candidate, The University of Western Australia
Jessica Meeuwig, Wen Family Chair in Conservation, The University of Western Australia
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/208269
2023-07-11T12:29:02Z
2023-07-11T12:29:02Z
Sawfish, guitarfish and more: Meet the rhino rays, some of the world’s most oddly shaped and highly endangered fishes
<figure><img src="https://images.theconversation.com/files/536338/original/file-20230707-2339-cd9dxd.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2891%2C1937&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An Atlantic guitarfish swimming in the Gulf of Mexico.
</span> <span class="attribution"><a class="source" href="https://flic.kr/p/8UpjyX">NOAA SEFSC Pascagoula Laboratory/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>“Shark!” When you hear this word, especially at the beach, it can conjure up images of bloodthirsty monsters. This summer, my colleagues and I are eager to help the public learn more about these misunderstood, ecologically important and highly threatened animals and <a href="https://www.britannica.com/animal/chondrichthian">their close relatives – rays and chimaeras</a>. </p>
<p>As a <a href="https://scholar.google.com/citations?user=xb7noGAAAAAJ&hl=en">marine biologist focused on conserving sharks</a>, I want people to know that an estimated one-third of them are <a href="https://doi.org/10.1016/j.cub.2021.08.062">at risk of extinction</a>. Second, there’s an amazing variety of species in an astounding variety of shapes sizes and colors, and many of them get very little attention. </p>
<p>Here is an introduction to a group of fishes that are at <a href="https://www.iucnssg.org/press/a-special-group-of-rays-are-now-worlds-most-threatened-marine-fish">extremely high risk of extinction</a>, and also delightfully weird: the rhino rays, named for their <a href="https://researchers.cdu.edu.au/en/publications/most-rhino-rays-sawfishes-wedgefishes-giant-guitarfishes-guitarfi">elongated noses</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/zYBSOjJe73w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientists tag endangered sawfish off Florida’s west coast to identify and protect their habitats and educate the public about them.</span></figcaption>
</figure>
<h2>Motley shapes</h2>
<p>Rhino rays are sharklike rays from five families: sawfish, wedgefish, giant guitarfish, guitarfish and banjo rays. The <a href="https://www.floridamuseum.ufl.edu/discover-fish/teaching-resources/sawfish-classroom-activities/what-is-a-sawfish/">sawfish</a> has a chainsaw-like extension in front of its mouth that it uses to stun and shred its prey. <a href="https://www.inaturalist.org/taxa/114627-Trygonorrhina-fasciata">Banjo rays</a> and <a href="https://www.fisheries.noaa.gov/species/common-guitarfish">guitarfishes</a> have body shapes that resemble those respective musical instruments. <a href="https://citessharks.org/wedgefishes">Wedgefishes</a> are, well, wedge-shaped, like doorstops with fins and tails. </p>
<p>These fishes are found in tropical and warm temperate waters all over the world, but many species have extremely restricted ranges. For example, the <a href="https://shark-references.com/species/view/Rhynchorhina-mauritaniensis">false shark ray</a> (<em>Rhynchorhina mauritaniensis</em>) is known to inhabit only one bay, on the coastline of Mauritania. </p>
<p>Rhino rays range in size, from 2 to 3 feet long (less than 1 meter) at one extreme to the largest species, the <a href="https://www.fisheries.noaa.gov/species/green-sawfish">green sawfish</a> (<em>Pristis zijsron</em>), which can grow to 23 feet (7 meters). They all are carnivores and eat all kinds of things, but mainly small crustaceans and fish, as well as worms that live in sand or mud. All rhino rays give birth to live young, just as mammals do. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/gt-sE14dYXs?wmode=transparent&start=6" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientists capture footage of a sawfish giving birth in the wild.</span></figcaption>
</figure>
<h2>Conservation strategies</h2>
<p>Sometimes rhino rays’ unusual features cause them problems. For example, fishing boats often haul in <a href="https://www.fisheries.noaa.gov/species/smalltooth-sawfish">smalltooth sawfish</a> (<em>Pristis pectinata</em>) as bycatch, or accidental catch, because their saws become tangled in fishing gear. Currently, shrimp trawl nets pose a serious threat to this species.</p>
<p>The smalltooth sawfish was the first marine fish species <a href="https://ecos.fws.gov/ecp/species/3253">listed under the U.S. Endangered Species Act</a>, in 2003. Once found from North Carolina to Texas, it now is restricted to small parts of south Florida, a range reduction of more than 95%. In some parts of the world, populations are starting to recover, but local extinction of sawfish from countries where they were once so common that they’re featured on currency has earned them the nickname “<a href="https://doi.org/10.1002/aqc.2525">Ghosts of the Coast</a>.” </p>
<p>Another rhino ray, the <a href="https://www.aquariumofpacific.org/onlinelearningcenter/species/bowmouth_guitarfish">bowmouth guitarfish</a> (<em>Rhina ancylostomus</em>), can grow up to 10 feet (3 meters) and has thornlike ridges covering its head and back. A recent study reported that these thorns are <a href="https://doi.org/10.1111/csp2.12896">actively traded online</a> among buyers who believe the thorns contain magical properties and use them to make protective amulets. While <a href="https://www.science.org/content/article/most-high-seas-shark-species-now-threatened-extinction">overfishing for fins and meat</a> is the most serious threat to sharks and rays overall, it also is important to consider these kinds of niche threats to some species.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CHtTyrqlQw7/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Fortunately, there are <a href="https://doi.org/10.1111/acv.12265">conservation solutions</a> that can be used to protect these animals and their important habitats. To reduce bycatch, some solutions require changing fishing gear. </p>
<p>“For gill nets, simple measures like lifting the net off the seafloor so sawfish have space to swim under them without getting tangled can help,” <a href="https://scholar.google.com.au/citations?user=bu2A-2kAAAAJ&hl=en">Charles Darwin University biologist Peter Kyne</a> told me in an interview. Using lights to illuminate nets has drastically reduced bycatch in some places. Kyne and his colleagues are testing <a href="https://doi.org/10.3354/esr01146">devices that generate electric fields underwater</a> to make sawfish swim away from nets so they don’t get entangled. </p>
<p>When bycatch can’t be averted, another strategy is training fishers to safely handle and release nontargeted species so that the fishes survive the encounter. Release-based conservation initiatives are an opportunity for scientists to <a href="https://doi.org/10.1111/acv.12651">collaborate with fishing communities</a> and the public. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/_Pohz3toARc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Researchers interview people in fishing communities in Goa, India, to understand the behavior of critically endangered guitarfishes and wedgefishes.</span></figcaption>
</figure>
<p>“For sawfishes, we started conservation work when species had already disappeared from across their historical range. We now have an opportunity to save the remaining species of rhino rays before it’s too late,” Rima Jabado, chair of the Shark Specialist Group for the International Union for the Conservation of Nature’s <a href="https://www.iucn.org/our-union/commissions/species-survival-commission">Species Survival Commission</a>, told me in an interview. “We know that fishing is the primary threat, and we have solutions to minimize bycatch.” </p>
<p>To learn more about rhino rays, follow #RhinoRay on Twitter and Instagram for posts from scientists, conservation experts, government agencies, zoos and aquariums all over the world. You can find the IUCN Species Survival Commission Shark Specialist Group on Twitter, Facebook and LinkedIn for weekly updates about the conservation status of these amazing and threatened animals. </p>
<p><em>Rima Jabado, chair of the IUCN Species Survival Commission Shark Specialist Group (SSG), contributed to this article.</em></p><img src="https://counter.theconversation.com/content/208269/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Shiffman currently serves as the communications officer for the IUCN Species Survival Commission Shark Specialist Group</span></em></p>
Rhino rays, which are close relative of sharks, are some of the most fascinating – and most threatened – fishes that you’ve never heard of.
David Shiffman, Faculty Research Associate in Marine Biology, Arizona State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/203491
2023-06-05T12:09:28Z
2023-06-05T12:09:28Z
Is there life in the sea that hasn’t been discovered?
<figure><img src="https://images.theconversation.com/files/529826/original/file-20230602-17-k2m7hu.jpeg?ixlib=rb-1.1.0&rect=6%2C2%2C1502%2C1002&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Rose-veiled fairy wrasse, a small reef fish discovered in 2022.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cirrhilabrus_finifenmaa_underwater_photograph_from_Rasdhoo_Atoll,_Maldives_-_Oo_654790.jpg">Luiz A. Rocha/Wikimedia Commons</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p>Is there life in the sea that hasn’t been discovered? – Haven W., age 12, McKinney, Texas</p>
</blockquote>
<hr>
<p>Imagine going to a place on Earth where no one has ever been. There are many locations like that in the ocean, which covers <a href="https://www.usgs.gov/special-topics/water-science-school/science/how-much-water-there-earth">more than 70% of our planet</a>. </p>
<p>In the ocean, creatures live at many different depths, just as animals and birds live at different heights in a forest. Every ocean life form has to find a way to gather nourishment, reproduce and contribute to an ecological community. </p>
<p>The ocean is <a href="https://theconversation.com/how-deep-is-the-ocean-121168">thousands of feet deep in many areas</a> and offers millions of opportunities for life to thrive. Biologists don’t know how many species live in the ocean, but they estimate that <a href="https://oceanservice.noaa.gov/facts/ocean-species.html">fewer than 10% have been described</a>. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CszRZcWPjHH/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Black and white smokers</h2>
<p>Fifty years ago, no one imagined that entire biologic communities were thriving in extreme darkness under the crushing pressures of the deep sea. Then they found them, at spots called <a href="https://oceanservice.noaa.gov/facts/vents.html">hydrothermal vents</a> – first with underwater cameras and thermometers, next by sending humans down in <a href="https://www.whoi.edu/what-we-do/explore/underwater-vehicles/hov-alvin/">Alvin, an underwater vehicle</a>. </p>
<p>The researchers found spots where hot water jetted upward through cracks in the seafloor, like geysers on land. Some of the water was as hot as 750 degrees Fahrenheit (400 degrees Celsius) – more than twice as hot as the oven when you bake a cake. And it was full of dissolved minerals. </p>
<p>As the hot water spilled onto the seafloor, where the water around it was much colder – just 36 F (2 C) – it quickly cooled, and the minerals solidified into stacks that looked like chimneys. Some were tens or hundreds of feet high. </p>
<p>Even in these cold, dark zones, the vents were home to all kinds of living organisms, including giant tube worms, clams, crabs and other species. Sunlight doesn’t reach deep enough in the ocean to serve as an energy source for these communities as it does for ecosystems on land. Instead, these complex ecosystems run on <a href="https://oceanexplorer.noaa.gov/facts/photochemo.html">chemosynthesis</a> – energy from chemical reactions between bacteria and the water. </p>
<figure>
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<figcaption><span class="caption">Deep-sea biologist Shannon Johnson describes hydrothermal vents and some of the creatures that thrive around them.</span></figcaption>
</figure>
<p>Bacteria that lived in the vents use chemicals such as hydrogen sulfide for energy to make carbohydrates. Then larger organisms feed on the bacteria and the creatures they nourish, and in turn are eaten by still larger creatures, creating a food chain.</p>
<p>Scientists first found “white smokers” – underwater vents where the superheated water deposited light-colored minerals, made of calcium and silicon – northeast of the <a href="https://oceanservice.noaa.gov/facts/vents.html">Galapagos Islands in 1977</a>. Then, in 1979, they found “black smokers,” made from darker, metal-rich minerals like iron sulfides, <a href="https://www.whoi.edu/feature/history-hydrothermal-vents/discovery/1979-2.html">at the southern tip of Baja Mexico</a>. </p>
<p>I was working at the Wood Hole Oceanographic Institution, which designed and built Alvin, when black smokers were discovered. The water around the vents was so hot that the plastic tip on Alvin’s external thermometer melted. We were worried for the safety of the researchers and pilot in Alvin because the thick plastic on the viewing portholes was the same composition as the thermometer tip. </p>
<p>But Alvin was well designed, and everyone survived. In fact, Alvin has been updated many times; scientists are still using it to explore deep reaches of the ocean.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/Bti1AbFnFuD/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Fluffy crabs and glowing worms</h2>
<p>Every year, scientists discover new marine species. Some swim in deep water or crawl and wiggle near or on the seafloor. Some, like slow-growing bacteria that inhabit the deep ocean crust, barely move at all. </p>
<p>Just in the past two years, researchers have found dozens of new species in the oceans. For example, there’s the “<a href="https://marinespecies.org/aphia.php?p=image&tid=1579238&pic=159908">fluffy” sponge crab (<em>Lamarckdromia beagle</em>)</a>, which decorates its shell with sponges, probably as camouflage from predators. </p>
<p>Another striking find, the <a href="https://www.calacademy.org/press/releases/stunning-new-to-science-fairy-wrasse-is-first-ever-fish-described-by-a-maldivian">Rose-veiled fairy wrasse (<em>Cirrhilabrus finifenmaa</em>)</a>, is a stunning pink reef fish from the Maldives, an island nation in the Indian Ocean.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1637242518550061056"}"></div></p>
<p>In Australia, scientists had been speculating for years about the origin of an unusual shark egg case in their country’s <a href="https://www.csiro.au/en/about/facilities-collections/collections/anfc">National Fish Collection</a>. In May 2023, they identified a new species of shark that produced it: the <a href="https://shark-references.com/species/view/Apristurus-ovicorrugatus">ghost or demon catshark (<em>Apristurus ovicorrugatus</em>)</a>, so called because its eyes have <a href="https://www.cbsnews.com/news/scientists-identify-new-species-of-demon-catshark-with-white-shiny-irises/">spooky-looking white irises</a>. </p>
<p>Three of the most intriguing new species are <a href="https://www.popsci.com/environment/bioluminescent-sea-worm-species-japan/">bioluminescent sea worms</a> that emit a bluish-violet light. The researchers who found the worms in shallow waters near Japan named one <em>Polycirrus Ikeguchi</em>, after a notable Japanese marine biologist named Shinichiro Ikeguchi. They called the other two <em>Polycirrus aoandon</em>, which means “blue lantern ghost,” and <em>Polycirrus onibi</em>, which means “demon fire.” Both names refer to spirits in Japanese folklore.</p>
<p>You can follow new discoveries as they are entered into the <a href="https://www.marinespecies.org/">World Register of Marine Species</a>. With 90% of ocean life still to describe, there are countless new discoveries to be made. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/203491/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Suzanne OConnell does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
From fluffy crabs that wear sea sponge hats to worms that glow in the dark, scientists are constantly finding amazing new life forms in the ocean.
Suzanne OConnell, Harold T. Stearns Professor of Earth Science, Wesleyan University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/199229
2023-06-01T12:30:00Z
2023-06-01T12:30:00Z
Invasive lionfish have spread south from the Caribbean to Brazil, threatening ecosystems and livelihoods
<figure><img src="https://images.theconversation.com/files/528927/original/file-20230529-34716-wug34x.jpg?ixlib=rb-1.1.0&rect=16%2C0%2C3591%2C2396&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An invasive lionfish at Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/23YKdEZ">G. P. Schmahl/NOAA</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Brazil’s coastal waters teem with a rich array of species that paint a living tapestry beneath the waves. This underwater world is particularly special because many of its species are <a href="https://www.britannica.com/science/endemic-species">endemic</a> – they are found nowhere else on Earth. The southwestern Atlantic is home to <a href="https://doi.org/10.1111/ddi.12729">111 endemic reef fish species</a>, each of which plays a crucial role in the intricate web of marine life. </p>
<p>An uninvited guest has arrived in these tropical waters: the <a href="https://invasions.si.edu/nemesis/species_summary/166883">Pacific red lionfish</a> (<em>Pterois volitans</em>). Renowned for its stunning appearance and voracious appetite, the lionfish was first detected off of Florida in 1985 and has spread throughout the Caribbean, <a href="https://www.fisheries.noaa.gov/southeast/ecosystems/impacts-invasive-lionfish">killing reef fish in large numbers</a>. </p>
<p>Now it has breached a formidable obstacle: the Amazon-Orinoco river plume, which flows into the Atlantic from northeastern Brazil. This massive discharge of fresh water has long <a href="http://dx.doi.org/10.1111/jbi.14398">functioned as a barrier</a> separating Caribbean fish species from those farther south along Brazil’s coastline.</p>
<p>Scientists and environmental managers widely agree that the lionfish invasion in Brazil is a potential ecological disaster. As a <a href="https://scholar.google.com.au/citations?user=_ArEYYMAAAAJ&hl=en">marine ecologist</a>, I believe mitigating the damage will require a comprehensive approach that addresses the ecological, social and economic harms wrought by this predatory fish.</p>
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<figcaption><span class="caption">Lionfish have no known predators and feed on the juveniles of important commercial fish species, such as grouper and snapper.</span></figcaption>
</figure>
<h2>Tracing the lionfish’s spread</h2>
<p>It’s easy to see why lionfish <a href="https://www.petco.com/content/petco/PetcoStore/en_US/pet-services/resource-center/caresheets/lionfish.html">appeal to aquarium enthusiasts</a>. Native to the warm waters of the Indo-Pacific ocean, they are 12 to 15 inches long, with red and white stripes and long, showy fins. They protect themselves with dorsal spines that deliver painful venomous stings.</p>
<p>Lionfish were first detected in the Atlantic Ocean <a href="https://myfwc.com/wildlifehabitats/profiles/saltwater/lionfish/">in 1985 off Dania Beach, Florida</a>, probably discarded by a tropical fish collector. Since then they have spread throughout the Caribbean Sea, the Gulf of Mexico and northward as far as <a href="https://www.pbsnc.org/blogs/science/rethinking-the-lionfish-invasion-hint-its-still-a-problem/">Bermuda and North Carolina</a> – one of the <a href="https://doi.org/10.1016/j.biocon.2013.04.014">most successful marine invasions on record</a>. A close relative, the common lionfish or devil firefish (<em>Pterois miles</em>), has <a href="https://doi.org/10.1111/jfb.14340">invaded the Mediterranean Sea</a> and is spreading rapidly there.</p>
<p>Lionfish can be eaten safely if they are properly prepared to remove their venomous spines. In Florida and the Caribbean, <a href="https://myfwc.com/fishing/saltwater/recreational/lionfish/events/">lionfish hunting tournaments</a> have become popular as a control method. However, lionfish <a href="https://doi.org/10.1007/s10530-016-1358-0">move to deeper waters as they grow</a>, so hunting alone can’t prevent them from spreading. </p>
<p>Marine scientists have anticipated for years that lionfish would someday arrive along the eastern coast of South America. <a href="https://doi.org/10.1038/nature.2015.17414">A single sighting in 2014</a>, far removed from the Amazon-Orinoco plume, was likely a result of an aquarium release rather than a natural migration. </p>
<p>Then in December 2020, local fishermen caught a pair of lionfish on coral reefs in the <a href="https://flowergarden.noaa.gov/about/mesophotic.html#">mesophotic, or “twilight,” zone</a> several hundred feet <a href="https://doi.org/10.1007/s10530-021-02575-8">below the mighty Amazon River plume</a>. A scuba diver also encountered a lionfish in the oceanic archipelago of <a href="https://whc.unesco.org/en/list/1000/">Fernando de Noronha</a>, 220 miles (350 kilometers) off Brazil’s tropical coast. </p>
<p>New invasion fronts have quickly opened along Brazil’s north and northeast coasts, covering eight states and diverse marine habitats. <a href="https://doi.org/10.3389/fmars.2022.956848">More than 350 lionfish have been tallied</a> along a 1,720-mile (2,765-kilometer) swath of coastline. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528934/original/file-20230529-15-37nsp4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map visualizing the spread of lionfish in the Atlantic, with orange dots representing recorded sightings as of 2023 from the ‘Lionfish Monitoring Dashboard,’ a collaborative project spearheaded by researchers at the Federal University of Ceará, Brazil.</span>
<span class="attribution"><a class="source" href="https://monitoramentos.shinyapps.io/LionfishWatch/">Lionfish Watch</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Aggressive predators without natural enemies</h2>
<p>Like many introduced species, lionfish in the Atlantic don’t face natural population control mechanisms such as predation, disease and parasitism that limit their numbers in the Indo-Pacific. A 2011 study found that lionfish on reefs in the Bahamas were <a href="https://doi.org/10.1007/s10530-011-0020-0">larger and more abundant</a> than their Pacific counterparts.</p>
<p>Lionfish thrive in many marine habitats, from mangroves and seagrass beds to deepwater reefs and shipwrecks. They are aggressive, persistent hunters that <a href="https://www.fisheries.noaa.gov/southeast/ecosystems/impacts-invasive-lionfish">feed on smaller fish</a>, including species that keep coral reefs clean and others that are food for important commercial species like snappers and groupers. In a 2008 study, when lionfish appeared on reefs in the Bahamas, populations of small juvenile reef fish <a href="https://doi.org/10.3354/meps07620">declined by 80% within five weeks</a>.</p>
<p>Brazil’s northeast coast, with its rich artisanal fishing activity, stands on the front line of this invasive threat. Lionfish are present in coastal <a href="https://oceanservice.noaa.gov/facts/mangroves.html">mangrove forests</a> and <a href="https://oceanservice.noaa.gov/facts/estuary.html">estuaries</a> – brackish water bodies where rivers meet the sea. These areas serve as nurseries for important commercial fish species. Losing them would increase the risk of hunger in a region that is already grappling with substantial social inequality. </p>
<p>Fishers also face the threat of lionfish stings, which are not lethal to humans but <a href="https://dan.org/alert-diver/article/lionfish-stings/">can cause painful wounds</a> that may require medical treatment.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Five people on a small boat near shore" src="https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529112/original/file-20230530-23-r3sjuy.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">Fishing is a major income source for Brazilians along the coast, like these in Cabo Frio, and could suffer if lionfish predation reduces catches.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/fishing-activity-is-a-major-source-of-income-for-the-news-photo/609864872">Luiz Souza/NurPhoto via Getty Images</a></span>
</figcaption>
</figure>
<h2>Facing the invasion: Brazil’s challenges</h2>
<p>Biological invasions are easiest to control in early stages, when the invader population is still growing slowly. However, Brazil has been slow to react to the lionfish incursion. </p>
<p>The equatorial southwestern Atlantic, where the invasion is taking place, has been less thoroughly surveyed than the Caribbean. There has been little high-resolution seabed mapping, which would help scientists identifying potential lionfish habitats and anticipate where lionfish might spread next or concentrate their populations. Understanding of the scale of the invasion is largely based on estimates, which likely underrepresent its true extent. </p>
<p>Moreover, turbid waters along much of Brazil’s coast make it hard for scientists to monitor and document the invasion. Despite their distinctive appearance, lionfish are difficult to spot and record in murky water, which makes it challenging for scientists, divers and fishers to keep an accurate record of their spread. </p>
<p>Still another factor is that from 2018 through 2022, under former President Jair Bolsonaro, Brazil’s government <a href="https://doi.org/10.1590/0001-3765202020200700">sharply cut the national science budget</a>, reducing funding for field surveys. The COVID-19 pandemic further reduced field research because of lockdowns and social distancing measures.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1655705639665168385"}"></div></p>
<h2>Making up for lost time</h2>
<p>Brazil has a history of inadequately monitoring for <a href="http://dx.doi.org/10.1126/science.abb7255">early detection of marine invasions</a>. The lionfish is no exception. Actions thus far have been reactive and often initiated too late to be fully effective. </p>
<p>As one of many Brazilian scientists who <a href="http://dx.doi.org/10.3354/meps10383">warned repeatedly</a> about a potential lionfish invasion over the past decade, I’m disheartened that my country missed the window to take early action. Now, however, marine researchers and local communities are stepping up.</p>
<p>Given the length of Brazil’s coast, traditional monitoring methods are often insufficient. So we’ve turned to citizen science and information technology to fill the gaps in our knowledge. </p>
<p>In April 2022, a group of academic researchers spearheaded the launch of an <a href="https://monitoramentos.shinyapps.io/LionfishWatch/">online dashboard</a>, which is updated continuously with data from scientific surveys and local community self-reports. This interactive platform is maintained by a research group led by marine scientists <a href="https://scholar.google.com/citations?user=HE-s5mUAAAAJ&hl=it">Marcelo Soares</a> and <a href="https://scholar.google.com.br/citations?user=FoB0KPgAAAAJ&hl=pt-BR">Tommaso Giarrizzo</a> from the Federal University of Ceará. </p>
<p>The dashboard allows anyone, from fishers to recreational divers and tourists, to upload data on lionfish observations. This information supports rapid response efforts, strategic planning for preventive measures in areas still free from lionfish, and the development of localized lionfish removal programs.</p>
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<figcaption><span class="caption">Artisanal fishers on Costa Rica’s southern Caribbean coast are working with regulators to curb the spread of invasive lionfish.</span></figcaption>
</figure>
<p>I believe lionfish are here to stay and will integrate over time into Brazil’s marine ecosystems, much as they have in the Caribbean. Given this reality, our most pragmatic and effective strategy is to reduce lionfish populations below levels that cause unacceptable ecological harm.</p>
<p>Regions along the coast that are still lionfish-free might benefit from early and preventive actions. Comprehensive surveillance plans should include environmental education programs about exotic species; early detection approaches, using techniques such as analyzing environmental DNA; citizen science initiatives to monitor and report lionfish sightings, participate in organized culls and help collect research data; and genetic surveys to identify patterns of connectivity among lionfish populations along Brazil’s coast and between Brazilian and Caribbean populations. </p>
<p>Brazil missed its initial opportunity to prevent the lionfish invasion, but I believe that with strategic, swift action and international collaboration, it can mitigate the impacts of this invasive species and safeguard its marine ecosystems. </p>
<p><em>This article has been updated to reflect that the correct number of endemic reef fish species in the southwestern Atlantic is 111.</em></p><img src="https://counter.theconversation.com/content/199229/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Osmar J. Luiz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
One of the most damaging invasive species in the oceans has breached a major barrier – the Amazon-Orinoco river plume – and is spreading along Brazil’s coast. Scientists are trying to catch up.
Osmar J. Luiz, Senior Research Fellow in Aquatic Ecology, Charles Darwin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/205557
2023-05-15T15:01:09Z
2023-05-15T15:01:09Z
You shed DNA everywhere you go – trace samples in the water, sand and air are enough to identify who you are, raising ethical questions about privacy
<figure><img src="https://images.theconversation.com/files/525993/original/file-20230512-24221-4caajm.png?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A casual stroll on the beach can leave enough intact DNA behind to extract identifiable information.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/human-footprint-on-the-sand-royalty-free-image/1030780262">Comezora/Moment via Getty Images</a></span></figcaption></figure><p>Human DNA can be sequenced from small amounts of water, sand and air in the environment to <a href="https://www.nature.com/articles/s41559-023-02056-2">potentially extract identifiable information</a> like genetic lineage, gender, and health risks, according to our new research.</p>
<p>Every cell of the body <a href="https://calteches.library.caltech.edu/2687/1/bonner.pdf">contains DNA</a>. Because each person has a unique genetic code, DNA can be <a href="https://theconversation.com/genetic-paparazzi-are-right-around-the-corner-and-courts-arent-ready-to-confront-the-legal-quagmire-of-dna-theft-178866">used to identify individual people</a>. Typically, medical practitioners and researchers obtain human DNA through direct sampling, such as blood tests, swabs or biopsies. However, all living things, including animals, plants and microbes, <a href="https://doi.org/10.1016/j.biocon.2014.11.019">constantly shed DNA</a>. The water, soil and even the air contain microscopic particles of biological material from living organisms.</p>
<p>DNA that an organism has shed into the environment is known as <a href="https://doi.org/10.1093/biosci/biab027">environmental DNA, or eDNA</a>. For the last couple of decades, scientists have been able to collect and sequence eDNA from soil or water samples to <a href="https://theconversation.com/fishing-for-dna-free-floating-edna-identifies-presence-and-abundance-of-ocean-life-75957">monitor biodiversity, wildlife populations</a> and <a href="https://theconversation.com/environmental-dna-how-a-tool-used-to-detect-endangered-wildlife-ended-up-helping-fight-the-covid-19-pandemic-158286">disease-causing pathogens</a>. Tracking rare or elusive endangered species <a href="https://doi.org/10.1007/s00114-019-1605-1">through their eDNA</a> has been a boon to researchers, since traditional monitoring methods such as observation or trapping can be difficult, often unsuccessful and intrusive to the species of interest.</p>
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<figcaption><span class="caption">The authors and their colleagues use environmental DNA to study sea turtles.</span></figcaption>
</figure>
<p>Researchers using eDNA tools usually focus only on the species they’re studying and disregard DNA from other species. However, humans <a href="https://theconversation.com/genetic-paparazzi-are-right-around-the-corner-and-courts-arent-ready-to-confront-the-legal-quagmire-of-dna-theft-178866">also shed</a>, cough and <a href="https://theconversation.com/who-sees-what-you-flush-wastewater-surveillance-for-public-health-is-on-the-rise-but-a-new-survey-reveals-many-us-adults-are-still-unaware-193007">flush DNA</a> into their surrounding environment. And as our team of geneticists, <a href="https://scholar.google.com/citations?user=czRqHV4AAAAJ&hl=en&oi=ao">ecologists</a> and <a href="https://scholar.google.com/citations?user=3cQ6umoAAAAJ&hl=en">marine biologists</a> in the <a href="https://scholar.google.com/citations?hl=en&user=LtNEh9gAAAAJ">Duffy Lab</a> at the University of Florida found, <a href="https://www.nature.com/articles/s41559-023-02056-2">signs of human life can be found everywhere</a> but in the most isolated locations. </p>
<h2>Animals, humans and viruses in eDNA</h2>
<p>Our team uses environmental DNA to study <a href="https://doi.org/10.1111/1755-0998.13617">endangered sea turtles and the viral tumors</a> to which they are susceptible. Tiny hatchling sea turtles shed DNA as they crawl along the beach on their way to the ocean shortly after they are born. <a href="https://doi.org/10.1111/1755-0998.13617">Sand scooped from their tracks</a> contains enough DNA to provide valuable insights into the turtles and the chelonid herpesviruses and <a href="https://theconversation.com/could-human-cancer-treatments-be-the-key-to-saving-sea-turtles-from-a-disfiguring-tumor-disease-98140">fibropapillomatosis tumors that afflict them</a>. Scooping a liter of <a href="https://doi.org/10.1038/s42003-021-02085-2">water from the tank</a> of a recovering sea turtle under veterinary care equally provides a wealth of genetic information for research. Unlike blood or skin sampling, collecting eDNA causes no stress to the animal.</p>
<p><a href="https://theconversation.com/genomic-sequencing-heres-how-researchers-identify-omicron-and-other-covid-19-variants-172935">Genetic sequencing technology</a> used to decode DNA has improved rapidly in recent years, and it is now possible to easily sequence the DNA of every organism in a sample from the environment. Our team suspected that the sand and water samples we were using to study sea turtles would also contain DNA from a number of other species – including, of course, humans. What we didn’t know was <a href="https://www.nature.com/articles/s41559-023-02056-2">just how informative</a> the human DNA we could extract would be. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people on a boat collecting water samples from a river" src="https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525991/original/file-20230512-33762-xb83ft.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>
<figcaption>
<span class="caption">The researchers were able to collect intact human DNA in water samples from a river in Florida.</span>
<span class="attribution"><span class="source">Todd Osborne</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>To figure this out, we took samples from a variety of locations in Florida, including the ocean and rivers in urban and rural areas, sand from isolated beaches and a remote island never usually visited by people. We found human DNA in all of those locations except the remote island, and these samples were high quality enough for analysis and sequencing. </p>
<p>We also tested the technique in Ireland, tracing along a river that winds from a remote mountaintop, through small rural villages and into the sea at a larger town of 13,000 inhabitants. We found human DNA everywhere but in the remote mountain tributary where the river starts, far from human habitation.</p>
<p>We also collected air samples from a room in our wildlife veterinary hospital in Florida. People who were present in the room gave us permission to take samples from the air. We recovered DNA matching the people, the animal patient and common animal viruses present at the time of collection.</p>
<p>Surprisingly, the human eDNA found in the local environment was intact enough for us to identify mutations associated with disease and to determine the genetic ancestry of people who live in the area. Sequencing DNA that volunteers left in their footprints in the sand even yielded part of their sex chromosomes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram depicting eDNA collection sources and analysis workflow" src="https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526004/original/file-20230513-16755-kheuum.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Human eDNA can be collected and analyzed from a variety of sources.</span>
<span class="attribution"><span class="source">Liam Whitmore/Created with BioRender.com</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Ethical implications of collecting human eDNA</h2>
<p>Our team dubs inadvertent retrieval of human DNA from environmental samples <a href="https://www.nature.com/articles/s41559-023-02056-2">“human genetic bycatch.”</a> We’re calling for deeper discussion about how to ethically handle human environmental DNA. </p>
<p>Human eDNA could present significant advances to research in fields as diverse as conservation, epidemiology, forensics and farming. If handled correctly, human eDNA could help archaeologists <a href="https://theconversation.com/who-owned-this-stone-age-jewellery-new-forensic-tools-offer-an-unprecedented-answer-204797">track down undiscovered ancient human settlements</a>, allow biologists to <a href="https://doi.org/10.1038/s42003-021-01656-7">monitor cancer mutations in a given population</a> or provide law enforcement agencies <a href="https://doi.org/10.1016/j.forsciint.2023.111599">useful forensic information</a>.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Footprints in the sand at a beach" src="https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=899&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=899&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=899&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525989/original/file-20230512-7632-rct90g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&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 researchers extracted identifiable genetic information from footprints in the sand.</span>
<span class="attribution"><span class="source">David Duffy</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>However, there are also myriad ethical implications relating to the inadvertent or deliberate collection and analysis of human genetic bycatch. Identifiable information can be extracted from eDNA, and accessing this level of detail about individuals or populations comes with <a href="https://theconversation.com/how-a-south-african-communitys-request-for-its-genetic-data-raises-questions-about-ethical-and-equitable-research-166940">responsibilities relating to consent and confidentiality</a>.</p>
<p>While we conducted our study with the approval of our <a href="https://doi.org/10.2146/ajhp070066">institutional review board</a>, which ensures that studies on people adhere to ethical research guidelines, there is no guarantee that everyone will treat this type of information ethically. </p>
<p>Many questions arise regarding human environmental DNA. For instance, who should have access to human eDNA sequences? Should this information be made publicly available? Should consent be required before taking human eDNA samples, and from whom? Should researchers remove human genetic information from samples originally collected to identify other species?</p>
<p>We believe it is vital to implement regulations that ensure collection, analysis and data storage are carried out ethically and appropriately. Policymakers, scientific communities and other stakeholders need to take human eDNA collection seriously and balance consent and privacy against the possible benefits of studying eDNA. Raising these questions now can help ensure everyone is aware of the capabilities of eDNA and provide more time to develop protocols and regulations to ensure appropriate use of eDNA techniques and the ethical handling of human genetic bycatch.</p><img src="https://counter.theconversation.com/content/205557/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica Alice Farrell received funding from the Gumbo Limbo Nature Center d/b/a Friends of Gumbo Limbo (a 501c3 non-profit organization) through a generous donation through their Graduate Research Grant programme</span></em></p><p class="fine-print"><em><span>Jenny Whilde does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Environmental DNA provides a wealth of information for conservationists, archaeologists and forensic scientists. But the unintentional pickup of human genetic information raises ethical questions.
Jenny Whilde, Adjunct Research Scientist in Marine Bioscience, University of Florida
Jessica Alice Farrell, Postdoctoral associate, University of Florida
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/202424
2023-04-18T12:44:48Z
2023-04-18T12:44:48Z
El Niño is coming, and ocean temps are already at record highs – that can spell disaster for fish and corals
<figure><img src="https://images.theconversation.com/files/521111/original/file-20230414-14-kbsx6w.jpg?ixlib=rb-1.1.0&rect=10%2C3%2C2385%2C1591&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Marine heat waves can reach the ocean floor as well as surface waters.</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/YV593oyMKmo">Sebastian Pena Lambarri via Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>It’s coming. Winds are weakening along the equatorial Pacific Ocean. Heat is building beneath the ocean surface. By July, <a href="https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/">most forecast models agree</a> that the climate system’s biggest player – El Niño – will return for the first time in nearly four years.</p>
<p>El Niño is one side of the climatic coin called the <a href="https://www.climate.gov/news-features/understanding-climate/el-ni%C3%B1o-and-la-ni%C3%B1a-frequently-asked-questions">El Niño-Southern Oscillation, or ENSO</a>. It’s the heads to La Niña’s tails.</p>
<p>During El Niño, a swath of ocean stretching 6,000 miles (about 10,000 kilometers) westward off the coast of Ecuador warms for months on end, typically by 2 to 4 degrees Fahrenheit (about 1 to 2 degrees Celsius). A few degrees may not seem like much, but in that part of the world, it’s more than enough to completely reorganize wind, rainfall and temperature patterns all over the planet.</p>
<figure class="align-center ">
<img alt="White corals indicate bleaching from heat stress." src="https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521376/original/file-20230417-26-ukagro.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">Marine heat waves can trigger coral bleaching.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/view-of-major-bleaching-on-the-coral-reefs-of-the-society-news-photo/1148857683">Alexis Rosenfeld/Getty Images</a></span>
</figcaption>
</figure>
<p>I’m a climate scientist who studies the oceans. After <a href="https://earthobservatory.nasa.gov/images/150691/la-nina-times-three">three years</a> of <a href="https://oceanservice.noaa.gov/facts/ninonina.html">La Niña</a>, it’s time to start preparing for what El Niño may have in store.</p>
<h2>How El Niño affects the planet</h2>
<p>No two El Niño events are exactly alike, though we’ve seen enough of them that forecasters have a pretty good idea of <a href="https://www.weather.gov/images/fwd/climate/enso/ElNino.png">what’s likely to happen</a>.</p>
<p>People tend to focus on El Niño’s impact on land, justifiably. The warm water affects air currents that leave areas wetter or drier than usual. It can ramp up storms in some areas, like the southern U.S., while <a href="https://tropical.colostate.edu/Forecast/2023-04.pdf">tending to tamp down Atlantic hurricane activity</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/wVlfyhs64IY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How El Niño forms. NOAA.</span></figcaption>
</figure>
<p>El Niño can also wreak havoc on the many marine ecosystems that support the world’s fishing industries, including <a href="https://theconversation.com/watching-a-coral-reef-die-as-climate-change-devastates-one-of-the-most-pristine-tropical-island-areas-on-earth-159792">coral reefs</a> and <a href="https://theconversation.com/restoring-seagrasses-can-bring-coastal-bays-back-to-life-147798">seagrass meadows</a>.</p>
<p>Specifically, El Niño tends to trigger intense and widespread periods of extreme ocean warming known as marine heat waves.</p>
<p><a href="https://www.theguardian.com/environment/2023/apr/08/headed-off-the-charts-worlds-ocean-surface-temperature-hits-record-high?CMP=share_btn_tw">Global ocean temperatures</a> are already <a href="https://climatereanalyzer.org/clim/sst_daily/">at record highs</a>, so El Niño-induced marine heat waves could push many sensitive fisheries to a breaking point.</p>
<h2>The problem with marine heat waves</h2>
<p>A marine heat wave is just that: a “wave” of extreme heat in the ocean, not dissimilar to an atmospheric heat wave on land. </p>
<p>At their smallest, marine heat waves can inundate <a href="https://doi.org/10.1029/2019JC015673">local bays and coves</a> with hotter-than-normal water for a few days or weeks. At their largest, marine heat waves like the <a href="https://doi.org/10.1002/2015GL063306">Northeast Pacific Warm Blob</a> of 2013-2014 can grow to gargantuan proportions, with regions <a href="https://indd.adobe.com/view/ffe33cde-3628-42e8-adc2-eaf85d8312e4">three times the size of Texas</a> experiencing ocean temperatures 4 to 6 F (about 2 to 3 C) above average for months or even years.</p>
<figure class="align-center ">
<img alt="An example of a marine heat wave showing intense heat." src="https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=363&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=363&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=363&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=456&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=456&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521094/original/file-20230414-24-5gh4an.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=456&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fierce marine heat waves like this one in 2019 can wreak havoc on sea life off the North American Pacific Coast with temperatures about 4 to 6 F (2 to 3 C) above normal.</span>
<span class="attribution"><span class="source">Dillon Amaya</span></span>
</figcaption>
</figure>
<p>Warm water might not seem like a big deal, especially to surfers hoping to leave their wetsuits at home. But for many marine organisms that are highly adapted to specific water temperatures, <a href="https://doi.org/10.1146/annurev-marine-032122-121437">marine heat waves can make living in the ocean feel like running a marathon</a>.</p>
<p>For example, some fish increase their metabolism in warm waters by so much that they burn energy faster than they can eat, and they can die. Pacific cod declined by 70% in the Gulf of Alaska in response to a marine heat wave. <a href="https://doi.org/10.1038/s41558-019-0412-1">Other impacts</a> include bleached corals, widespread harmful algal blooms, decimated seaweeds and increased marine mammal strandings. All told, <a href="https://www.annualreviews.org/doi/10.1146/annurev-marine-032122-121437">billions of U.S. dollars are lost</a> to marine heat waves each year.</p>
<p>Marine heat waves flare up for a <a href="https://doi.org/10.1038/s41467-019-10206-z">variety of reasons</a>. Sometimes ocean currents shift warm water around. Sometimes surface winds are weaker than normal, leading to less evaporation over the ocean and warmer waters. Sometimes cloudy places just aren’t as cloudy for a few months, which lets more sunlight in and heats up the ocean. Sometimes both weaker winds and fewer clouds happen at the same time, producing <a href="https://doi.org/10.1038/s41467-020-15820-w">record-breaking marine heat waves</a>.</p>
<h2>Where El Niño fits in</h2>
<p>In the climate system, El Niño is king. When it dons its fiery crown, the entire planet takes notice, and the oceans are no exception. But the likelihood of increased marine heat wave activity during El Niño depends on where you are.</p>
<p>Along the U.S. West Coast during El Niño, surface winds that normally blow from the north tend to subside. This weakens evaporation and <a href="https://oceanservice.noaa.gov/education/tutorial_currents/03coastal4.html">slows upwelling</a> of colder, deeper water. That increases the chances of coastal marine heat waves.</p>
<p><iframe id="17ZbA" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/17ZbA/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Peruvian fishers have for centuries weathered periods of extreme ocean warming that drive fish away. <a href="https://earthobservatory.nasa.gov/features/ElNino/page3.php">It wasn’t until the 1920s</a> that scientists realized that these South American marine heat waves were related to the Pacificwide ENSO.</p>
<p>In the Bay of Bengal east of India, interactions between El Niño and a tropical air flow pattern known as the <a href="https://www.climate.gov/news-features/blogs/enso/walker-circulation-ensos-atmospheric-buddy">Walker Circulation</a> elevate the risk for marine heat waves.</p>
<h2>Seafloor heat waves are another risk</h2>
<p>Even if marine heat waves aren’t more obvious at the ocean surface this year, it doesn’t mean all is well down below.</p>
<p>In a <a href="https://doi.org/10.1038/s41467-023-36567-0">recent study</a>, my colleagues and I showed that marine heat waves also unfold along the seafloor of coastal regions. In fact, these “bottom marine heat waves” are sometimes more intense than their surface counterparts. They can also persist much longer. For example, a 1997-1998 bottom marine heat wave off the U.S. West Coast lasted an extra four to five months after surface ocean temperatures had already cooled.</p>
<p>Events like this can be related to El Niño and put a lot of stress on bottom-dwelling species. Bering Sea snow crab landings were down 84% in 2018 after a marine heat wave reached the seafloor.</p>
<h2>We’re in (for) hot water</h2>
<p>With El Niño on the horizon, what can we expect for this year?</p>
<p>The good news is <a href="https://doi.org/10.1038/s41586-022-04573-9">seasonal forecast models can skillfully predict marine heat waves</a> three to six months in advance, depending on the region. And forecasts tend to be most accurate during El Niño years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing where marine heat waves are forecast in October 2023." src="https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=292&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=292&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=292&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=367&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=367&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521512/original/file-20230418-28-f96w6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=367&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">NOAA’s marine heat wave forecast issued in early April predicting October 2023.</span>
<span class="attribution"><a class="source" href="https://psl.noaa.gov/marine-heatwaves/">NOAA/Jacox, et al. 2022</a></span>
</figcaption>
</figure>
<p><a href="https://psl.noaa.gov/marine-heatwaves/">The latest forecast</a> predicts several active marine heat waves to persist into June-August, including in the North Pacific, off the coast of Peru, southeast of New Zealand and in the tropical North Atlantic.</p>
<p>The same forecasts predict El Niño to ramp up over the next six to nine months, increasing marine heat wave risk in January to March of 2024 for the U.S. West Coast, the western Indian Ocean, the Bay of Bengal, and the tropical North Atlantic. </p>
<p>That said, these predictions are far enough out that things could change. Time will tell whether they hold (hot) water, but we would do well to prepare. El Niño is coming.</p><img src="https://counter.theconversation.com/content/202424/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dillon Amaya does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
El Niño can trigger intense and widespread periods of extreme ocean warming known as marine heat waves. They can devastate marine life.
Dillon Amaya, Climate Research Scientist, National Oceanic and Atmospheric Administration
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/203231
2023-04-04T20:20:35Z
2023-04-04T20:20:35Z
Monsters or masters of the deep sea? Why the deepest of deep-sea fish aren’t as scary as you might think
<figure><img src="https://images.theconversation.com/files/519199/original/file-20230404-14-lonkuu.jpg?ixlib=rb-1.1.0&rect=411%2C425%2C1506%2C652&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.uwa.edu.au/news/Article/2023/April/Scientists-break-new-record-after-finding-worlds-deepest-fish">Caladan Oceanic</a>, <span class="license">Author provided</span></span></figcaption></figure><p>How deep can fish live in the ocean? That question has captivated me for more than a decade. But my research team’s discovery of the <a href="https://www.uwa.edu.au/news/Article/2023/April/Scientists-break-new-record-after-finding-worlds-deepest-fish">deepest sea fish</a>, announced this week, might not be the final answer. There may be more. How deep – and how strange – remains open for debate.</p>
<p>Last year, my colleagues and I went on an expedition to the deep trenches around Japan. Having already found the <a href="https://theconversation.com/how-we-found-worlds-deepest-fish-in-the-mariana-trench-and-why-we-must-keep-exploring-35743">Mariana snailfish</a> in 2014 – thought to be the deepest ever – we had a hunch that with more exploration and a better understanding of things like temperature, the Japanese trenches would host a fish at even greater depths. </p>
<p>After another 63 deployments of our deep-sea cameras, bringing our total to about 250 across the globe, we hit the jackpot.</p>
<p>We found what is likely a new species of fish in the Izu-Ogasawara Trench and filmed it many times at depths between 6,500 and 8,000 metres. Then, at a staggering 8,336m, a rather unassuming little juvenile slowly swam past the camera, oblivious to the fact it had just become the <a href="https://www.uwa.edu.au/news/Article/2023/April/Scientists-break-new-record-after-finding-worlds-deepest-fish">deepest fish on record</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/wG1je9DDzbg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Researchers near Japan capture footage of deepest fish ever recorded underwater (The Guardian)</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ten-things-you-never-knew-about-the-oceans-deepest-places-55172">Ten things you never knew about the ocean’s deepest places</a>
</strong>
</em>
</p>
<hr>
<h2>Much more than monsters</h2>
<p>If you ask someone what the deepest fish in the world looks like, they will probably conjure up an image of a scaly, black, stealthy creature with bioluminescent lures, large fangs, spiny fins and demonic eyes lurking in the depths waiting to strike at unsuspecting victims. It would be nothing like the shallow-water fish we eat, keep as pets, or pay to see in aquariums. It would be more the stuff of nightmares.</p>
<p>While these sorts of visually striking creatures do exist, they are often not that deep, or that big. Hatchet fish, fangtooth, lanternfish, dragonfish, viperfish and angler fish inhabit the mid-waters of the twilight zone (less than 1,000m deep). Many of these classically spooky monsters are actually very small and are simply enlarged in our imagination, in the absence of any sense of physical scale.</p>
<figure class="align-center ">
<img alt="Side profile of the deep ocean Sloane viperfish (Chauliodus sloani)" src="https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=438&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=438&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=438&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=550&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=550&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519205/original/file-20230404-20-7n3dx9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=550&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sloane’s Viperfish is one of the most recognizable deep sea fishes with its long fang-like teeth.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sloane-viperfish-chauliodus-sloani-deep-ocean-2257607267">Diego Grandi/Shutterstock</a></span>
</figcaption>
</figure>
<p>The black body, big eyes, bioluminescent lures and unfamiliar fins and textures are all adaptations to stealthy but efficient living in low-light conditions. </p>
<p>At deeper levels, where low-light adaptations are no longer required (because there’s a total absence of light), marine life takes on different, less dramatic forms. Adaptations to depth, or rather high pressure, are not usually things we can see, but rather changes at the level of cells or body tissues, to enable life at depth. </p>
<p>If we take, for example, the <a href="https://theconversation.com/snailfish-how-we-found-a-new-species-in-one-of-the-oceans-deepest-places-103003">deepest fish</a>, the <a href="https://academic.oup.com/jcb/article/41/1/ruaa102/6128500?login=true">deepest prawn</a>, the <a href="https://link.springer.com/article/10.1007/s00227-023-04177-5">deepest jellyfish</a>, the deepest anemone and the <a href="https://link.springer.com/article/10.1007/s00227-020-03701-1">deepest octopus</a>, we find them at depths of 8,336m, 7,703m, 10,000m, 10,900m and 7,000m, respectively (between 4.3 and 6.8 miles deep).</p>
<h2>The deepest of the deep</h2>
<p>The deepest fish in the world isn’t really a deep-sea fish. They are snailfish in the family of ray-finned fishes called Liparidae. There are more than 400 species of snailfish, and most are found in shallow waters, or even estuaries in some cases. This family of fish has adapted to an array of different environmental settings and habitats, including the deepest. </p>
<p>We found the deepest of all in the Izu-Ogasawara Trench at 8,336m, but this fish does not conform to any preconceived visual impression of what the deepest dweller should look like. They are in fact small, translucent pink, quirky little fish that swim like tadpoles and would not look out of place in a sunlit lagoon. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two deep-sea snailfish specimens, like pink tadpoles, resting on a dark grey background" src="https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519202/original/file-20230404-20-m322pa.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>
<figcaption>
<span class="caption">These two specimens are the deepest fish ever caught, recovered from a depth of 8022m in the Japan trench.</span>
<span class="attribution"><span class="source">Alan Jamieson</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Similarly, if we look at the deepest of the big crustaceans, which happen to be penaeid prawns (<em>Benthesicymus</em>), there is nothing all that unfamiliar about them. The can be up to a foot long, strikingly red in colour, and swim and behave in exactly the way one would expect a prawn to swim and behave in our coastal regions. It would not look out of place at the local fish market.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/deep-sea-reefs-are-spectacular-and-barely-explored-they-must-be-conserved-197566">Deep sea reefs are spectacular and barely-explored – they must be conserved</a>
</strong>
</em>
</p>
<hr>
<p>The deepest jellyfish looks like a normal jellyfish. The deepest anemones can be found attached to rocks at the very bottom of the Challenger Deep, the deepest place on Earth. These as yet unknown species are attached to rocks that filter food out of the water. They appear more plant-like, resembling delicate and beautiful flowers swaying in the wind. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two deep-sea images of the white anemone that resembles delicate and beautiful flowers swaying in the wind" src="https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519206/original/file-20230404-22-bko7fm.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"></a>
<figcaption>
<span class="caption">Like delicate flowers from an underwater garden at the deepest place on Earth, the deepest anemones.</span>
<span class="attribution"><span class="source">Caladan Oceanic</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>And then there is the octopus, an animal that has haunted sailors for centuries. In contrast, the newly discovered species of Dumbo octopus (<em>Grimpoteuthis</em>) is a small and cute little cephalopod with fins that resemble big ears (as in Dumbo the elephant). The species was filmed nearly 2,000 metres deeper than any other octopus or squid at a depth of nearly 7,000m.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/OX7w5EcDX9o?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A guide to the Dumbo octopus, from Deep Marine Scenes.</span></figcaption>
</figure>
<h2>The true masters</h2>
<p>Essentially, dark-sea creatures in the upper ocean detract from the real deep-sea creatures, giving us a false impression of the natural aesthetic of this community. </p>
<p>While the dark-sea animals have adapted to low light in a way that jars our imagination, the true deep-sea animals represent more of a case of where the wild things aren’t. </p>
<p>The snailfish are the true masters of the deep, not monsters of the deep. If we are to ever truly understand the ocean, and appreciate it as the largest habitat on Earth, we should retrain our brains and realise that even thousands of metres underwater, there are populations of little fish just going about their daily business.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A still image from deep sea video footage showing an octopus, snailfish and a prawn PLEASE CHECK approaching the fish food lure" src="https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519207/original/file-20230404-16-9ynrlj.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"></a>
<figcaption>
<span class="caption">Coming for dinner, an octopus, two cusk eels and a prawn approaching one of the deep-sea cameras.</span>
<span class="attribution"><span class="source">Caladan Oceanic</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-ocean-is-not-a-quiet-place-184543">The ocean is not a quiet place</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/203231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Jamieson receives funding from the Minderoo Foundation. </span></em></p>
The discovery of the deepest fish in a Japanese trench raises the question, what else is out there? But before the mind leaps to all things dark and spooky, take a fresh look at life in the deep sea.
Alan Jamieson, Founding Professor of the Minderoo-UWA Deep-Sea Research centre, The University of Western Australia
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/197134
2023-02-01T13:24:59Z
2023-02-01T13:24:59Z
Scientists envision an ‘internet of the ocean,’ with sensors and autonomous vehicles that can explore the deep sea and monitor its vital signs
<figure><img src="https://images.theconversation.com/files/505223/original/file-20230118-24-dogl3z.jpg?ixlib=rb-1.1.0&rect=753%2C753%2C7205%2C4708&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A large robot, loaded with sensors and cameras, designed to explore the ocean twilight zone.</span> <span class="attribution"><a class="source" href="https://twilightzone.whoi.edu/work-impact/technology/mesobot/">Marine Imaging Technologies, LLC © Woods Hole Oceanographic Institution</a></span></figcaption></figure><p><em>Deep below the ocean surface, the light fades into a twilight zone where whales and fish migrate and dead algae and zooplankton rain down from above. This is the <a href="https://www.youtube.com/watch?v=Fma6MM359Z0">heart of the ocean’s carbon pump</a>, part of the natural ocean processes that capture about a third of all human-produced carbon dioxide and sink it into the deep sea, where it remains for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838858/">hundreds of years</a>.</em> </p>
<p><em>There may be ways to enhance these processes so the ocean pulls more carbon out of the atmosphere to help slow climate change. Yet little is known about the consequences.</em></p>
<p><em>Peter de Menocal, a <a href="https://scholar.google.com/citations?hl=en&user=Etpzd_UAAAAJ&view_op=list_works&sortby=pubdate">marine paleoclimatologist</a> and director of Woods Hole Oceanographic Institution, discussed ocean carbon dioxide removal at a recent <a href="https://tedxboston.com/planetary-stewardship/">TEDxBoston:</a> <a href="https://www.youtube.com/playlist?list=PLLZP1f7L84FqRhJeC_72AsKm4ZvJgdqwT">Planetary Stewardship</a> event. In this interview, he dives deeper into the risks and benefits of human intervention and describes an ambitious plan to build a vast monitoring network of autonomous sensors in the ocean to help humanity understand the impact.</em></p>
<h2>First, what is ocean carbon dioxide removal, and how does it work in nature?</h2>
<p>The ocean is like a big carbonated beverage. Although it doesn’t fizz, it has <a href="https://science.nasa.gov/earth-science/oceanography/ocean-earth-system/ocean-carbon-cycle">about 50 times more carbon</a> than the atmosphere. So, for taking carbon out of the atmosphere and storing it someplace where it won’t continue to warm the planet, the ocean is the <a href="https://essd.copernicus.org/articles/14/4811/2022/">single biggest place it can go</a>.</p>
<p>Ocean carbon dioxide removal, or ocean CDR, uses the ocean’s natural ability to take up carbon on a large scale and amplifies it.</p>
<figure class="align-center ">
<img alt="Illustration showing methods of carbon storage, including growing kelp" src="https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=416&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=416&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505217/original/file-20230118-23-d817gq.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=416&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Methods of ocean carbon storage.</span>
<span class="attribution"><span class="source">Natalie Renier/©Woods Hole Oceanographic Institution</span></span>
</figcaption>
</figure>
<p><iframe id="XZVDq" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/XZVDq/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Carbon gets into the ocean from the atmosphere in two ways.</p>
<p>In the first, air <a href="https://www.whoi.edu/press-room/news-release/the-oceans-biological-pump-captures-more-carbon-than-expected/">dissolves into the ocean surface</a>. Winds and crashing waves mix it into the upper half-mile or so, and because seawater is slightly alkaline, the carbon dioxide is absorbed into the ocean.</p>
<p>The second involves the biologic pump. The ocean is a living medium – it has algae and fish and whales, and when that organic material is eaten or dies, it gets recycled. It rains down through the ocean and makes its way to the ocean twilight zone, a level around 650 to 3300 feet (roughly 200 to 1,000 meters) deep.</p>
<figure><img src="https://cdn.theconversation.com/static_files/files/2494/whoi2.gif?1672717556"><figcaption>The years indicate how long deposited carbon is expected to remain before the water cycles to the surface. Woods Hole Oceanographic Institution</figcaption></figure>
<p>The ocean twilight zone sustains biologic activity in the oceans. It is the “soil” of the ocean where organic carbon and nutrients accumulate and are recycled by microbes. It is also home to the largest animal migration on the planet. Each day trillions of fish and other organisms migrate from the depths to the surface to feed on plankton and one another, and go back down, acting like a large carbon pump that captures carbon from the surface and shunts it down into the deep oceans where it is stored away from the atmosphere.</p>
<h2>Why is ocean CDR drawing so much attention right now?</h2>
<p>The single most shocking sentence I have read in my career was in the <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/">Intergovernmental Panel on Climate Change’s Sixth Assessment Report</a>, released in 2021. It said that we have delayed action on climate change for so long that removing carbon dioxide from the atmosphere is now necessary for all pathways to keep global warming <a href="https://climate.nasa.gov/news/2865/a-degree-of-concern-why-global-temperatures-matter/">under 1.5 degrees Celsius</a> (2.7 F). Beyond that, climate change’s impacts become increasingly dangerous and unpredictable.</p>
<p>Because of its volume and carbon storage potential, the ocean is really the only arrow in our quiver that has the ability to take up and store carbon at the scale and urgency required.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/JeYjSPuyjgc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Peter de Menocal at TEDxBoston: Planetary Stewardship.</span></figcaption>
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<p>A 2022 <a href="https://nap.nationalacademies.org/catalog/26278/a-research-strategy-for-ocean-based-carbon-dioxide-removal-and-sequestration">report by the national academies</a> outlined a research strategy for ocean carbon dioxide removal. The three most promising methods all explore ways to enhance the ocean’s natural ability to take up more carbon.</p>
<p>The first is <a href="https://www.whoi.edu/know-your-ocean/ocean-topics/climate-weather/ocean-based-climate-solutions/">ocean alkalinity enhancement</a>. The oceans are salty – they’re naturally alkaline, with a <a href="https://www.whoi.edu/know-your-ocean/ocean-topics/how-the-ocean-works/ocean-chemistry/ocean-acidification/">pH of about 8.1</a>. Increasing alkalinity by dissolving certain powdered rocks and minerals makes the ocean a chemical sponge for atmospheric CO2.</p>
<figure class="align-center ">
<img alt="Vibrant corals of many types and colorful fish." src="https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/503166/original/file-20230105-129741-5tcaos.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">Studies show increasing alkalinity can also reduce ocean acidification stress on corals.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Great_barrier_reef.JPG">Wise Hok Wai Lum/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>A second method adds micronutrients to the surface ocean, particularly soluble iron. Very small amounts of <a href="https://www.nature.com/articles/s41612-022-00250-w">soluble iron can stimulate greater productivity</a>, or algae growth, which drives a more vigorous biologic pump. Over a dozen of these experiments have been done, so we know it works.</p>
<p>Third is perhaps the easiest to understand – <a href="https://nap.nationalacademies.org/read/26278/chapter/1">grow kelp in the ocean</a>, which captures carbon at the surface through photosynthesis, then bale it and sink it to the deep ocean. </p>
<p>But all of these methods have drawbacks for large-scale use, including cost and <a href="https://www.smithsonianmag.com/science-nature/complicated-role-iron-ocean-health-and-climate-change-180973893/">unanticipated consequences</a>.</p>
<figure class="align-center ">
<img alt="The view looking toward the ocean surface through a kelp forest." src="https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505225/original/file-20230118-7884-4i46xa.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">
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<span class="caption">Kelp takes up carbon dioxide during photosynthesis.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sunlight-streaming-through-a-forest-of-giant-kelp-news-photo/635826440">David Fleetham/VW PICS/Universal Images Group via Getty Images</a></span>
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<p>I’m not advocating for any one of these, or for ocean CDR more generally. But I do believe accelerating research to understand the impacts of these methods is essential. The ocean is essential for everything humans depend on – food, water, shelter, crops, climate stability. It’s the <a href="https://sos.noaa.gov/catalog/datasets/ocean-atmosphere-co2-exchange/">lungs of the planet</a>. So we need to know if these ocean-based technologies to reduce carbon dioxide and climate risk are viable, safe and scalable.</p>
<h2>You’ve talked about building an ‘internet of the ocean’ to monitor changes there. What would that involve?</h2>
<p>The ocean is changing rapidly, and it is the single biggest cog in Earth’s climate engine, yet we have almost no observations of the subsurface ocean to understand how these changes are affecting the things we care about. We’re basically flying blind at a <a href="https://www.nature.com/articles/d41586-020-00915-7">time when we most need observations</a>. Moreover, if we were to try any of these carbon removal technologies at any scale right now, we wouldn’t be able to measure or verify their effectiveness or assess impacts on ocean health and ecosystems.</p>
<p>So, we are leading an initiative at Woods Hole Oceanographic Institution to build the <a href="https://www.whoi.edu/wp-content/uploads/2022/07/OVSN_Carbon.mp4?_=1">world’s first internet for the ocean</a>, called the <a href="https://www.whoi.edu/fowler-center-ocean-climate/related-activities-and-initiatives/">Ocean Vital Signs Network</a>. It’s a large network of moorings and sensors that provides 4D eyes on the oceans – the fourth dimension being time – that are always on, always connected to monitor these carbon cycling processes and ocean health. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration showing where different species live at different depths in the ocean." src="https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505221/original/file-20230118-17-lamel0.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>
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<span class="caption">Top predators such as whales, tuna, swordfish and sharks rely on the twilight zone for food, diving down hundreds or even thousands of feet to catch their prey.</span>
<span class="attribution"><span class="source">Eric S. Taylor /© Woods Hole Oceanographic Institution</span></span>
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<p>Right now, there is about one <a href="https://argo.ucsd.edu/">ocean sensor</a> in the global Argo program for every patch of ocean the size of Texas. These go up and down like pogo sticks, mostly measuring temperature and salinity.</p>
<p>We envision <a href="https://www.whoi.edu/fowler-center-ocean-climate/related-activities-and-initiatives/#:%7E:text=The%20Ocean%20Vital%20Signs%20Network,circulation%20patterns%2C%20geochemical%20reactions%2C%20and">a central hub in the middle of an ocean basin</a> where a dense network of intelligent gliders and autonomous vehicles measure ocean properties including carbon and other vital signs of ocean and planetary health. These vehicles can dock, repower, upload data they’ve collected and go out to collect more. The vehicles would be sharing information and making intelligent sampling decisions as they measure the chemistry, biology and environmental DNA for a volume of the ocean that’s really representative of how the ocean works.</p>
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<img alt="A large robot with a light and sensors descends into darker water" src="https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505212/original/file-20230118-14-8t42gg.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">
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<span class="caption">Mesobot starts its descent toward the ocean twilight zone.</span>
<span class="attribution"><span class="source">Marine Imaging Technologies, LLC © Woods Hole Oceanographic Institution</span></span>
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<p>Having that kind of network of autonomous vehicles, able to come back in and power up in the middle of the ocean from wave or solar or wind energy at the mooring site and send data to a satellite, could launch a new era of ocean observing and discovery.</p>
<h2>Does the technology needed for this level of monitoring exist?</h2>
<p>We’re already doing much of this engineering and technology development. What we haven’t done yet is stitch it all together.</p>
<p>For example, we have a team that works with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5240338/">blue light lasers</a> for communicating in the ocean. Underwater, you can’t use electromagnetic radiation as cellphones do, because seawater is conductive. Instead, you have to use sound or light to communicate underwater.</p>
<p>We also have an <a href="https://acomms.whoi.edu/">acoustics communications</a> group that works on <a href="https://techtransfer.whoi.edu/whoi-engineers-work-to-adapt-swarming-capabilities-for-low-cost-uuvs/">swarming technologies</a> and communications between nearby vehicles. Another group works on how to dock vehicles into <a href="https://www.whoi.edu/know-your-ocean/ocean-topics/ocean-tech/moorings-buoys/">moorings in the middle of the ocean</a>. Another specializes in mooring design. Another is building chemical sensors and physical sensors that measure ocean properties and environmental DNA. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/Fma6MM359Z0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A tour of sea life in the ocean twilight zone.</span></figcaption>
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<p>This summer, 2023, <a href="https://twilightzone.whoi.edu/about/">an experiment in the North Atlantic</a> called the Ocean Twilight Zone Project will image the larger functioning of the ocean over a big piece of real estate at the scale at which ocean processes actually work.</p>
<p>We’ll have acoustic transceivers that can create a 4D image over time of these dark, hidden regions, along with gliders, new sensors we call “minions” that will be looking at ocean <a href="https://twilightzone.whoi.edu/work-impact/technology/">carbon flow, nutrients and oxygen changes</a>. “<a href="https://www.youtube.com/watch?v=TaNZH1sXGEo">Minions</a>” are basically sensors the size of a soda bottle that go down to a fixed depth, say 1,000 meters (0.6 miles), and use essentially an iPhone camera pointing up to take pictures of all the material floating down through the water column. That lets us quantify how much organic carbon is making its way into this old, cold deep water, where it can remain for centuries.</p>
<p>For the first time we’ll be able to <a href="https://twilightzone.whoi.edu/work-impact/technology/">see just how patchy productivity is</a> in the ocean, how carbon gets into the ocean and if we can quantify those carbon flows. </p>
<p>That’s a game-changer. The results can help establish the effectiveness and ground rules for using CDR. It’s a Wild West out there – nobody is watching the oceans or paying attention. This network makes observation possible for making decisions that will affect future generations.</p>
<h2>Do you believe ocean CDR is the right answer?</h2>
<p>Humanity doesn’t have a lot of time to reduce carbon emissions and to lower carbon dioxide concentrations in the atmosphere.</p>
<p>The reason scientists are working so diligently on this is not because we’re big fans of CDR, but because we know the oceans may be able to help. With an ocean internet of sensors, we can really understand how the ocean works including the risks and benefits of ocean CDR.</p><img src="https://counter.theconversation.com/content/197134/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter de Menocal is the president and director of Woods Hole Oceanographic Institution.</span></em></p>
The ocean twilight zone could store vast amounts of carbon captured from the atmosphere, but first we need a 4D monitoring system to ensure ramping up carbon storage does no harm.
Peter de Menocal, Director, Woods Hole Oceanographic Institution
Licensed as Creative Commons – attribution, no derivatives.