tag:theconversation.com,2011:/fr/topics/sharks-1561/articlesSharks – The Conversation2024-03-27T13:27:11Ztag:theconversation.com,2011:article/2247152024-03-27T13:27:11Z2024-03-27T13:27:11ZGo on an Easter egg case hunt on the beach to discover more about sharks and rays<figure><img src="https://images.theconversation.com/files/579193/original/file-20240301-20-bnz9ap.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Egg cases found along the foreshore can tell scientists a lot about the abundance and life cycles of sharks and rays</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-shark-egg-case-resting-on-1983639383">Ross Mahon/Shutterstock</a></span></figcaption></figure><p>Strolling along the shoreline, you may come across peculiar pouch-like objects on the sand. These leathery treasures are shark egg cases, also known as mermaid’s purses. Each capsule can tell us something about how sharks and rays reproduce, the lives they lead and how rare they might be. </p>
<p>The Shark Trust’s <a href="https://www.sharktrust.org/greateggcasehunt">great egg case hunt</a> encourages people to document their foreshore findings. Different sharks and rays produce egg cases with distinct characteristics. Skates and rays tend to have more elongated pouches with horn-like protrusions at each end. Shark egg cases often have spiral coiled tendrils which can be lodged into crevices or attached to underwater structures such as rocks, seaweed, or coral reefs.</p>
<p>These protective structures are produced by the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0016648022001010#:%7E:text=Reproductive%20strategies%20of%20elasmobranchs%20(sharks%2C%20rays%20and%20skates)%20have,species%20(Compagno%2C%201990).">40% of sharks and rays</a> and <a href="https://www.sharktrust.org/pups-skates-rays">all skates</a> that lay eggs. Each egg case safeguards an embryo from predators and harsh environmental conditions during their early stages of life. </p>
<p>Shark egg cases can be found around the world, in coastal waters, estuaries and deep ocean environments. Particularly after storms or during low tide, egg cases may become dislodged from their attachment sites on the ocean floor and end up on beaches. </p>
<h2>Record your findings</h2>
<p>If you come across an egg case while exploring the beach, try not to disturb or open it because it may contain precious shark or ray eggs. Avoid removing it from the beach (doing so may well be illegal in some parts of the world) and, as with any beach discovery, leave the area as you found it.</p>
<p>Take a moment to examine the egg case. Note its size, shape, colour and any other distinguishing features. Photograph the egg case from different angles and try to identify which species it came from using The Shark Trust’s <a href="https://www.sharktrust.org/geh-id">useful guide</a>. Record the precise location, date and time that you found the egg case. </p>
<p>Log your findings via citizen science projects such as the great egg case hunt, or report your discovery to local marine research organisations, aquariums or conservation groups that may be collecting data on egg case sightings. </p>
<p>Share your experience with friends, relatives and other beachgoers to raise awareness about the importance of shark and ray conservation. Encourage others to respect marine life and their habitats to ensure their preservation.</p>
<h2>A natural process</h2>
<p>The washing up of shark egg cases is a perfectly natural process. Some sharks and rays deposit their egg cases in shallow waters or near the shoreline, where they may become dislodged by wave action, currents, or storms. This helps to disperse the embryos and maintain genetic diversity within populations. Once the tide comes in, egg cases can be washed back into the sea allowing for further dispersal, so not all shark egg cases found on beaches are stranded or in need of intervention. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Underwater shot of yellow transparent egg case with dark-coloured live embryo inside , purple sea coral" src="https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579203/original/file-20240301-18-pcqiev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&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">Egg cases are designed to protect the embryos of sharks and rays.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dogfish-shark-eggs-close-hanging-red-326395700">Andrea Izzotti/Shutterstock</a></span>
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<p>If the embryos inside the egg cases are fully developed and ready to hatch, returning them to the sea may indeed increase their chances of survival. But if the water is too shallow, turbid or polluted, it may not be suitable for the survival of the embryos. Handling egg cases or disturbing them unnecessarily could inadvertently harm the developing embryos. So if you have concerns about the welfare of the embryos or the environmental conditions, consult with local marine conservation experts or beach authorities for guidance.</p>
<h2>Tracking cycles</h2>
<p>Identifying which species are present in a particular area can indicate the reproductive activity of local shark and ray populations. By monitoring the abundance and distribution of egg cases over time, scientists can track reproductive cycles and assess the health of populations. </p>
<p>While some species may reproduce all year round, others may have specific breeding seasons tied to environmental cues such as water temperature or daylight hours. Understanding the reproductive biology and habitat requirements of sharks and rays helps protect these vulnerable species and conserve their habitats.</p>
<p>Recordings of egg case sightings enable scientists to build up a picture of any changes in the abundance or condition of shark egg cases that might be indicative of broader environmental changes. The decline in the number of egg case sightings may suggest threats such as habitat degradation or over-fishing. Stormy weather or changes in ocean currents may also affect the distribution and abundance of egg cases by washing them ashore or dispersing them in the water. </p>
<p>Egg cases are fascinating structures that provide valuable information about sharks and rays. Next time you visit a beach, remember that each and every piece of debris, natural or human-made, tells a story about the interconnected web of life in the ocean. Take a closer look at what has been washed up on the shore and enjoy going on a shark egg case hunt.</p><img src="https://counter.theconversation.com/content/224715/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas Ray 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>Egg cases of sharks and rays can be found washed up on the shore. Citizen science data helps scientists understand the life cycles of these marine animals and how to best conserve them.Nicholas Ray, Doctoral School Programmes Manager, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2265132024-03-27T01:14:51Z2024-03-27T01:14:51ZThese extraordinary Australian islands are teeming with life – and we must protect them before it’s too late<p>In the Southern Ocean about 4,000 kilometres from Perth lies a truly extraordinary place. Known as the Heard Island and McDonald islands, they are among the most remote places on Earth: a haven for marine life amid the vast ocean, virtually undisturbed by human pressures.</p>
<p>But as our <a href="https://research-repository.uwa.edu.au/en/publications/understanding-the-marine-ecosystems-surrounding-heard-island-and-">report</a> released today reveals, this special place in Australia’s territory is at risk. In particular, climate change is warming the waters around the islands, threatening a host of marine life.</p>
<p>More than 20 years ago, a marine reserve was declared over the islands and parts of the surrounding waters. At the time, it was a significant step forward in environmental protection. But since then, science has progressed and the threats have worsened. </p>
<p>Our report reviewed these protections and found they are no longer adequate. The marine reserve surrounding the Heard and McDonald islands must urgently be expanded. </p>
<h2>Spotlight on the reserve system</h2>
<p>The Heard and McDonald islands are just a tiny tip of the Kerguelen Plateau – a huge underwater mass rising high above the surrounding ocean basins. </p>
<p>The plateau intercepts the Antarctic Circumpolar Current, the strongest current system in the world. When the current hits the plateau, deep, nutrient-rich waters are pushed to the surface. This supports a food chain ranging from tiny plankton to fish, invertebrates, seabirds and marine mammals such as elephant seals and sperm whales.</p>
<p>On Heard Island, Mawson’s Peak is officially Australia’s highest mountain. It is 2,745 metres high and forms the summit of an active volcano known as Big Ben. Heard Island and McDonald Islands also host valuable fisheries for Patagonian toothfish and mackerel icefish.</p>
<p>The marine reserve around the islands was declared in 2002 and extended in 2014. It now covers 17% of what is known as the “exclusive economic zone” – the area of the sea in which a nation (in this case, Australia) has exclusive rights to resources such as fish and minerals.</p>
<p>The original reserve was primarily designed for waters shallower than 1,000m, because in 2002 little was known about the area’s deeper waters. A review of the reserve system is due this year.</p>
<p>Our report draws on more than 20 years’ of research conducted since the reserve was first declared. It highlights new scientific understanding of the region and the need to expand its protection.</p>
<p><iframe id="oSiut" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/oSiut/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Climate pressures on the plateau</h2>
<p>Climate change poses wicked threats for the Heard and McDonald islands and surrounding marine environment. </p>
<p>We found the shelf area is <a href="https://www.nature.com/articles/s41467-020-20781-1">becoming warmer</a>. This potentially threatens species adapted to cold polar waters, such as the mackerel icefish. This species lives in shallow water and is an important food source for fur seals and other predators. </p>
<p>No other sub-antarctic shelf exists to the south of Heard Island, which means the region is a vital animal habitat. Maintaining the islands’ biodiversity in the face of climate change is best achieved by extending the existing marine reserve to cover more shallow waters, as well as protecting currently unprotected deeper waters.</p>
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<strong>
Read more:
<a href="https://theconversation.com/australias-only-active-volcanoes-and-a-very-expensive-fish-the-secrets-of-the-kerguelen-plateau-123351">Australia's only active volcanoes and a very expensive fish: the secrets of the Kerguelen Plateau</a>
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<h2>Protecting deep-water species</h2>
<p>The Patagonian toothfish is a top predator species that connects different parts of the food web. Commercial fishing in the islands’ economic zone targets toothfish using “<a href="https://www.fisheries.noaa.gov/national/bycatch/fishing-gear-bottom-longlines">bottom longlines</a>” which are weighted to the seafloor at depths down to 2,000m. The footprint of fishing operations has expanded over the past 30 years.</p>
<p>Our report suggests protecting <a href="https://www.sciencedirect.com/science/article/pii/S0304380016303325">spawning grounds</a> of toothfish will reduce risks to this species and help ensure the fishery does not deplete fish stock.</p>
<p>Fishing is managed in such a way to eliminate the accidental catching (or by-catch) of seabirds. But there is still significant by-catch of a number of non-target fish species, especially skates. </p>
<p>Keeping fishing out of some areas can reduce pressure on vulnerable species. Important areas for achieving this are in the deeper waters to the southeast of Heard Island. </p>
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Read more:
<a href="https://theconversation.com/climate-risk-index-shows-threats-to-90-per-cent-of-the-worlds-marine-species-190221">Climate risk index shows threats to 90 per cent of the world's marine species</a>
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<h2>Sustaining biodiversity into the future</h2>
<p>Our analysis reveals an updated understanding of the marine ecosystems surrounding Heard and McDonald islands.</p>
<p>Scientists now know more about where <a href="https://www.sciencedirect.com/science/article/abs/pii/S1470160X16302977">marine mammals and birds forage</a> – particularly in the important period when parents are feeding their young. We found some species that breed on Heard Island, including king penguins and fur seals, rely on areas not protected by the marine reserve during these times.</p>
<p>Our analysis also reveals a complex mosaic of productive habitats in shallow water, and less productive habitats in deeper water. This in turn affects the distribution of animal species.</p>
<p>Increased protection for the areas in the west, south, and southeast of the economic zone will be needed to protect animals in these habitats.</p>
<figure class="align-center ">
<img alt="Increased protections are needed to protect biodiversity in the region." src="https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/298059/original/file-20191022-28092-12ocbi6.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">Bird activity behind a research vessel near the Kerguelen Plateau.</span>
<span class="attribution"><span class="source">Paul Tixier</span></span>
</figcaption>
</figure>
<h2>Looking ahead</h2>
<p>The current marine reserve covering Heard and McDonald islands is not sufficient. It should cover deeper water ecosystems and provide protection for foraging areas of resident seals, penguins and albatross. </p>
<p>Protecting spawning grounds of toothfish and areas important to cold-adapted species, such as mackerel icefish, will help ensure these species have the best chance against continuing warming of the ocean. </p>
<p>Extending the protections would help Australia meet its domestic policy and international agreements. For example, the federal government has committed to protecting <a href="https://theconversation.com/weve-committed-to-protect-30-of-australias-land-by-2030-heres-how-we-could-actually-do-it-217795">at least 30%</a> of ocean ecosystems by 2030.</p>
<p>It would also ensure our marine protected areas are <a href="https://www.dcceew.gov.au/environment/marinereservesreview/resources/representative-system">nationally representative</a> – a key national objective Australia has committed to.</p>
<p>By extending adequate protection of Heard and McDonald islands, Australia has the chance to show global leadership in conserving this precious natural asset in the Southern Ocean.</p><img src="https://counter.theconversation.com/content/226513/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The report underpinning this article was part-funded by Pew Charitable Trusts and the Australian Marine Conservation Society.</span></em></p>A new report has found the marine reserve covering the Heard and McDonald islands must urgently be expanded.Ian Cresswell, Adjunct professor, The University of Western AustraliaAndrew J Constable, Adviser, Antarctica and Marine Systems, Science & Policy, University of TasmaniaKeith Reid, Honorary Research Associate, Institute for Marine and Antarctic Studies, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2232672024-03-08T13:36:46Z2024-03-08T13:36:46ZRare 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>
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<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>
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<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>
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<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>
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<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 FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2218062024-02-02T17:35:14Z2024-02-02T17:35:14ZHow trophy fishing can have a sustainable future<figure><img src="https://images.theconversation.com/files/572280/original/file-20240130-29-g3zie3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Blue sharks are popular targets of a catch-and-release fishery along the southern coast of England</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/magnificent-blue-shark-elegant-proud-look-2318078271">Vladimir Turkenich/Shutterstock</a></span></figcaption></figure><p>It was 1984, and a hot tropical sun beat down on the inky blue depths of the Huon Gulf, a large inlet of the Solomon Sea just off the coast of Papua New Guinea. Suddenly, the peace was broken by the scream of a fishing reel as a four-metre-long blue marlin (<em>Makaira mazaraburst</em>) burst from the water. </p>
<p>For the next hour the giant fish surged, leapt and tail walked, as my best friend and fishing companion mostly just held on. Then, suddenly, it was gone. </p>
<p>The trace had frayed. No fishermen likes to lose a fish, but for me, there was also a sense of relief that it had got away. That fish was the most magnificent creature I’d ever seen, and that moment helped inspire my lifelong career in marine biology.</p>
<p>Recreational fishing for the largest species and individual fish in the sea like this is often called trophy fishing. Anglers seek to set new size records, either overall or using particular line strengths. These can be incredible specimens – the <a href="https://www.marlinmag.com/biggest-marlin-ever-caught/">largest marlin ever caught</a> weighed over 700kg, similar to a small car. </p>
<h2>What’s the catch?</h2>
<p><a href="https://onlinelibrary.wiley.com/doi/10.1002/aqc.4051">In a new paper</a>, we analysed 80 years of trophy fishing world records, using data recorded by the International Game Fishing Association (IGFA) to reveal some intriguing trends. Notably, in the 1950s, the average record-holding fish weighed a hefty 168kg, but this figure fell drastically to just 8kg in the 2010s. </p>
<p>The fish are not shrinking, instead anglers are now targeting a broader range of smaller species. However, this might signal a concerning decline in the population of larger fish species.</p>
<p>There has also been a noticeable expansion of trophy fishing worldwide. While the US dominated the scene historically, recent decades have seen an uptick in records from regions like Japan and New Zealand. </p>
<p>This global spread offers potential social and economic benefits to these new areas, but also raises concerns about increased fishing pressure on local fish populations that were previously less targeted.</p>
<p>Perhaps our most significant observation was the sharp decline in new records for fish species listed as threatened with extinction by the International Union for Conservation of Nature. Comparing the last decade (2010–2018) to the 2000s, there has been a roughly 66% decrease in records for these at-risk species. </p>
<p>This trend could indicate a growing awareness towards conservation issues in trophy fishing or could reflect the worrying reality of diminished populations of these species. The exact implications of this trend are yet to be fully understood.</p>
<p>Trophy fishing is controversial. Some people will never be fans. The largest fish in the ocean are often <a href="https://academic.oup.com/icesjms/article/71/8/2171/748104">the most productive breeders</a>, so catching and killing them, especially threatened species, doesn’t make sense. However, while world record fish accredited by the IGFA gain the spotlight, they account for a very small number of fish in total. </p>
<p>Much more concerning are the fishing tournaments that offer <a href="https://www.bisbees.com/News/Article/166">highly lucrative prizes</a> for landing the largest and most fish and <a href="https://sharkallies.org/shark-fishing-tournaments">sharks</a> in a given period of time. </p>
<h2>Tackling sustainability</h2>
<p>Trophy fishing, and sport fishing in general, is changing to become more sustainable, and even a force for good. In 2011, the IGFA introduced the <a href="https://igfa.org/announcement/igfa-launches-all-tackle-length-record-release-category/">“all-tackle length” category</a>. This approach records the length of the fish rather than weight, enabling it to be released without needing to kill it. </p>
<p>The Shark Angling Club of Great Britain has been releasing all sharks for decades and the <a href="https://anglingtrust.net/2023/11/22/update-from-british-record-fish-committee/">British Record Fish Committee</a> recently decided to only allow length-based records for large sharks, with fish having to be measured while still in the water. Although releasing fish does not guarantee survival, that can be maximised by using <a href="https://academic.oup.com/conphys/article/11/1/coad100/7503354">the right gear and careful handling</a>. Such approaches should become mandatory for all trophy anglers.</p>
<p>Anglers dedicate extensive time to their passion, developing a wealth of knowledge about the fish they catch. Harnessing this expertise is crucial for better estimating the extent of trophy fishing and increasing knowledge of fish stocks in general. </p>
<p>In the UK, anglers and scientists are working together through initiatives such as <a href="https://anglingtrust.net/sea/sea-angling-science/shark-hub-uk/">Shark Hub UK</a> and <a href="https://anglingtrust.net/sea/sea-angling-science/pollack-project/">Project Pollack</a> to gather catch data, collect samples and tag fish. </p>
<p>This approach not only aids conservation efforts but also aligns with the anglers’ interest in maintaining healthy fish populations for the future. After all, the recreational fisheries are not only a source of livelihood but also contribute to the <a href="https://www.mdpi.com/2673-3986/4/3/30">mental and physical wellbeing</a> of those who engage with them.</p>
<p>Nearly 40 years after that experience in Papua New Guinea, I marvelled at huge schools of giant fish off the coast of southern England last summer. These Atlantic bluefin tuna (<em>Thunnus thynnus</em>) have had <a href="https://academic.oup.com/icesjms/article/78/5/1672/6231587?login=false">a remarkable recovery</a> around the coast, most likely due to a combination of improved management and changing environmental conditions. </p>
<p>From this year, the UK government has authorised a <a href="https://www.gov.uk/government/news/recreational-fishing-for-atlantic-bluefin-tuna-set-to-start-in-english-waters-next-year#:%7E:text=Each%20UK%20fisheries%20administration%20will,commercial%20fishery%20for%20bluefin%20tuna.">catch and release only recreational fishery</a> for these fish. With continued careful management this should bring exciting angling, social and economic benefits for years to come.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Bryce Stewart receives funding from Defra and UK Research and Innovation. He is a member of the Marine Conservation Society and the Yorkshire Wildlife Trust and sits on the Marine Stewardship Council Stakeholder Advisory Council.</span></em></p><p class="fine-print"><em><span>James Boon 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>Trophy fishing is a big threat to some of the most threatened species of fish, but there are ways to adapt the sport with marine conservation in mind.Bryce Stewart, Senior research fellow, Marine Biological AssociationJames Boon, PhD candidate in Marine Ecology, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2206292024-01-31T13:36:25Z2024-01-31T13:36:25Z‘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>
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<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>
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<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 FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189022024-01-11T13:25:55Z2024-01-11T13:25:55ZTo protect endangered sharks and rays, scientists are mapping these species’ most important locations<figure><img src="https://images.theconversation.com/files/565884/original/file-20231214-27-kjjzka.jpg?ixlib=rb-1.1.0&rect=60%2C0%2C6720%2C4426&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A tiger shark swims among surgeonfish off Fuvahmulah Atoll, Maldives, in the Indian Ocean.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/tiger-shark-with-shoal-of-fish-surgeonfishes-indian-royalty-free-image/1262279323">imageBROKER/Norbert Probst via Getty Images</a></span></figcaption></figure><p>All of the saltwater bodies on Earth make up <a href="https://oceanservice.noaa.gov/facts/howmanyoceans.html">one big ocean</a>. But within it, there is infinite variety – just ask any scuba diver. Some spots have more coral, more sea turtles, more fish, more life. </p>
<p>“I’ve been diving in many places around the world, and there are few locations like the <a href="https://visitfuvahmulah.mv/discover-fuvahmulah/">Fuvahmulah Atoll</a> in the Maldives,” Amanda Batlle-Morera, a research assistant with the <a href="https://sharkrayareas.org/">Important Shark and Ray Areas project</a>, told me. “You can observe tiger sharks, thresher sharks, scalloped hammerheads, oceanic manta rays and more, without throwing out bait to attract them.” </p>
<p>Identifying areas like Fuvahmulah that are especially important to certain species is a <a href="https://www.fws.gov/sites/default/files/documents/critical-habitat-fact-sheet.pdf">long-standing strategy</a> for protecting threatened land animals, birds and marine mammals, such as whales and dolphins. Now our team of marine conservation scientists at the <a href="https://sharkrayareas.org/">Important Shark and Ray Areas project</a> is using it to help protect sharks and their relatives. </p>
<p>I am a <a href="https://scholar.google.com/citations?user=xb7noGAAAAAJ&hl=en">marine conservation biologist</a> and the project’s communications officer. This initiative is working to identify locations that are critical for sharks and rays, so that these zones can be flagged for future protection or fisheries management measures. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0mPBvhGvZLI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Divers get close views of tiger sharks at Fuvahmulah, an offshore island in the southern Maldives. Six threatened shark species and one threatened ray species appear regularly in the area.</span></figcaption>
</figure>
<h2>Where the sharks are</h2>
<p>Sharks and their relatives are some of the most imperiled animals on Earth: More than one-third of all known species are <a href="https://doi.org/10.1016/j.cub.2021.08.062">threatened with extinction</a>. Many of these animals play vital roles in their ecosystems. Losing marine predators <a href="https://doi.org/10.1016/j.tree.2008.01.003">can destabilize entire food webs</a> and the ecosystems that these food webs depend on.</p>
<p>In recent years, the management of sharks and their relatives, rays and chimaeras, has largely focused on curbing the impacts of fisheries and trade on these species. But their populations <a href="https://doi.org/10.1016/j.cub.2021.08.062">are still declining rapidly</a>, so new strategies are needed. </p>
<p>To effectively protect these important and threatened animals, my colleagues and I believe it is vital to identify and protect parts of the ocean, plus some freshwater habitats, that are especially significant for their lives. Some areas, for example, are important migratory pathways, or feeding or mating grounds, or places to lay eggs. </p>
<p>Our team has created a <a href="https://doi.org/10.3389/fmars.2022.968853">list of technical criteria</a> so that zones around the world can be examined and potentially designated as Important Shark and Ray Areas. We modeled these criteria on similar approaches that are already in use, such as <a href="https://doi.org/10.1641/0006-3568(2004)054%5B1110:KBAASC%5D2.0.CO;2">important marine mammal areas</a>, which we adapted to the specific needs and biology of sharks and their relatives. </p>
<p>We are now hosting a series of 13 regional workshops around the world and inviting local experts to nominate preliminary areas of interest for evaluation by our team and an independent expert review panel. So far, we’ve completed three workshops, one focusing on the Central and South American Pacific, another on the Mediterranean and Black seas, and the third on the Western Indian Ocean, with a workshop for Asia planned for early 2024. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A world map shows zones that scientists have identified as Important Shark and Ray Areas in the Pacific and Indian oceans and the Mediterranean Sea." src="https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568049/original/file-20240105-14-7s4g8o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&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 current version of the online atlas of Important Shark and Ray Areas. The atlas is organized by region, showing which parts of the world’s oceans and coasts have been assessed.</span>
<span class="attribution"><a class="source" href="https://sharkrayareas.org/">Important Shark and Ray Areas initiative</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>After the workshops and expert reviews, each finalized Important Shark and Ray Area will be added to our e-atlas, which <a href="https://sharkrayareas.org/e-atlas/">can be viewed online</a>. Each region’s Important Shark and Ray Areas are published in a formal compendium, and the whole global process will be repeated every 10 years. This cycle will allow us to consider changes to areas that have already been mapped, such as new fishery policies or impacts from climate change, and to take into account new research that can help us identify new areas. </p>
<h2>Informing conservation policies</h2>
<p>We recently published our <a href="https://sharkrayareas.org/download/mediterranean-and-black-seas-regional-compendium-of-important-shark-and-ray-areas/">Mediterranean and Black seas region compendium</a>, which reflects input from over 180 experts from around the region. It identifies 65 Important Shark and Ray Areas that range widely in size and habitat type. Our <a href="https://sharkrayareas.org/download/western-indian-ocean-regional-compendium-of-important-shark-and-ray-areas/">western Indian Ocean compendium</a> includes over 125 areas. </p>
<p>These zones are important for species like the critically endangered <a href="https://www.fisheries.noaa.gov/species/blackchin-guitarfish">blackchin guitarfish</a> (<em>Glaucostegus cemiculus</em>), as well as heavily fished shark species like the <a href="https://www.sharks.org/smoothhound-mustelus-mustelus">common smoothhound shark</a> (<em>Mustelus mustelus</em>). </p>
<p>Some of these areas, such as <a href="https://sharkrayareas.org/portfolio-item/benidorm-island-isra/">Benidorm Island</a> off Spain’s Mediterranean coast, are in shallow coastal zones. Others, like the <a href="https://sharkrayareas.org/wp-content/uploads/isra-factsheets/12CentralSouthPacific/Cocos-Galapagos-Swimway-12CentralSouthPacific.pdf">Cocos-Galapagos Swimway</a> off Costa Rica and Ecuador, reach into deep ocean waters. </p>
<p>The smallest area identified so far, Israel’s <a href="https://sharkrayareas.org/wp-content/uploads/isra-factsheets/03MedBlackSeas/Palmahim-Brine-Pools-03MedBlackSeas.pdf">Palmahim brine pools</a> in the southeast Mediterranean, measures just 0.03 square miles (0.09 square kilometers) – about half the size of New York City’s Grand Central station. <a href="https://eol.org/pages/46560072">Blackmouth catsharks</a>
(<em>Galeus melastomus</em>) breed and lay eggs there, and threatened <a href="https://eol.org/pages/46560287">angular rough sharks</a> (<em>Oxynotus centrina</em>) feed there, including on blackmouth catshark eggs. </p>
<p>The largest area is the <a href="https://sharkrayareas.org/wp-content/uploads/isra-factsheets/03MedBlackSeas/Strait-of-Sicily-and-Tunisian-Plateau-03MedBlackSeas.pdf">Strait of Sicily and Tunisian Plateau</a>, which extends over 77,000 square miles (200,000 square kilometers) – about the size of Great Britain – in the Mediterranean between Sicily, Malta, western Libya and Tunisia. This zone supports at least 32 species of sharks, rays and chimaeras, including many that are at risk of extinction, in habitats ranging from shallow seagrass beds to deep ocean trenches.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CsHnxebvcsp/?utm_source=ig_web_copy_link\u0026igsh=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Identifying a location as an Important Shark and Ray Area does not mean it will automatically be protected. Our goal is to inform countries’ existing spatial planning and fisheries management processes and other conservation planning. Eventually, these zones may be incorporated into <a href="https://oceanexplorer.noaa.gov/facts/mpas.html">marine protected areas</a> or other types of ocean preserves.</p>
<p>Sharks and their relatives need human help to survive and maintain their important biological roles in the ocean. Through the Important Shark and Ray Areas project, hundreds of scientists and other experts are helping to identify special places for these species that we believe need some extra attention.</p>
<p><em>Dr. Rima Jabado, chair of the IUCN Species Survival Commission Shark Specialist Group, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/218902/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Shiffman 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>A new initiative is pinpointing areas in the world’s oceans that are key habitats for sharks and their relatives, so that governments can consider protecting these areas.David Shiffman, Faculty Research Associate in Marine Biology, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2201062024-01-09T13:25:50Z2024-01-09T13:25:50ZI 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>
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</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 MiamiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2185192024-01-02T20:16:26Z2024-01-02T20:16:26ZJaws turns 50: reading Peter Benchley’s novel, you barely mind if its self-loathing characters are eaten by a ‘genius’ shark<p>How many times have you come out of the cinema and heard someone snidely remark they preferred the book, as though this somehow connects them to a richer, more highbrow tradition?</p>
<p>This might ring true when it comes to literary masterworks like F. Scott Fitzgerald’s The Great Gatsby, adapted into <a href="https://www.imdb.com/title/tt1343092/">so-so</a> <a href="https://www.imdb.com/title/tt0071577/">versions</a> nearly four decades apart (equally dull, for almost opposite reasons). But the reverse is often the case with popular fiction, which benefits from the immersive, visceral quality of the cinema.</p>
<p>Peter Benchley’s 1974 novel <a href="https://www.panmacmillan.com.au/9781447220039/">Jaws</a>, which turns 50 this year, was a smash. Despite critics’ reservations, it was on the New York Times bestseller list for 44 weeks. Yet when we think of Jaws, images from Steven Spielberg’s 1975 film adaptation are what come to mind – along with John Williams’ <a href="https://youtu.be/E-sX2Y0W8l0?si=7H4TUsSRrImq_eh-">iconic theme music</a>. </p>
<p>Spielberg’s <a href="https://www.imdb.com/title/tt0073195/">Jaws</a> keeps the simple – and stunning – narrative architecture of Benchley’s novel intact. A shark terrorises a small beach community that depends on wealthy tourists for sustenance. Brody, the chief of police, keeps the beaches open due to political pressure from Mayor Vaughan; when more attacks occur, marine biologist Matt Hooper comes to help. Together, they contract wild shark hunter Quint to help them kill the great white. </p>
<p>But the tone of grand adventure that defines Spielberg’s film marks a major departure from the novel. In Benchley’s work, more energy is directed towards exploring the minor social and political lives of its small-town denizens than in staging an epic showdown between man and beast – and, crucially, it differs radically from the film in its characterisation. In Spielberg’s world, the main characters are likeable, heroic, whereas in the novel they’re petty, broken and bitter, wading through the messes their personal lives have become. </p>
<p>These differences are not simply evidence of a young director’s desire to make the material his own. They map the changing consciousness of American popular culture in the 1970s, from a resolute focus on the violence simmering within United States society and policy (the civil rights movement and the Vietnam War) to an attempt to forget about these things through spectacular, anodyne entertainment. </p>
<p>As we know, Spielberg’s film reshaped Hollywood, virtually single-handedly inventing the “blockbuster” and marking a significant shift away from the existentially charged, sometimes nihilistic, ever self-critical films of the previous decade or so. </p>
<p>Yet the two dominant themes situating Benchley’s novel in a rich American literary tradition also underpin the film: its biting look at small-town politics and economics, and its reverent study of a wilderness awesome and sublime. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-jaws-to-star-wars-to-harry-potter-john-williams-90-today-is-our-greatest-living-composer-176245">From Jaws to Star Wars to Harry Potter: John Williams, 90 today, is our greatest living composer</a>
</strong>
</em>
</p>
<hr>
<h2>‘The shark material is brilliant’</h2>
<p>At the novel’s core is a swift, economically told tale of human versus beast: a classic American adventure in the vein of Jack London’s <a href="https://www.penguin.com.au/books/white-fang-9780241652664">White Fang</a> or Herman Melville’s <a href="https://www.penguin.com.au/books/moby--dick-9780451532282">Moby-Dick</a>. </p>
<p>Benchley punctuates this drama with a keen interrogation of the social dynamics of small American communities in the context of the economic pressures of capitalism. </p>
<p>A career journalist, Benchley is effective in describing actions, events and scenery: shark hunting, the ocean, Quint’s boat. The shark material is brilliant – the few times it cuts to the shark’s point of view (recalling Spielberg’s redeployment of the creature’s point of view from <a href="https://www.imdb.com/title/tt0046876/">Creature from the Black Lagoon</a>), the writing becomes electric, effortless. Benchley is at his best when describing the movements of the shark in the water. </p>
<p>For example, when Hooper is cage diving, towards the end of the novel: </p>
<blockquote>
<p>The head was only a few feet from the cage when the fish turned and began to pass before Hooper’s eyes – casually, as if in proud display of its incalculable mass and power. The snout passed first, then the jaw, slack and smiling, armed with row upon row of serrate triangles. And then the black, fathomless eye, seemingly riveted upon him. The gills rippled – bloodless wounds in the steely skin.</p>
</blockquote>
<p>But the material about people is less confident – the writing is uneven and trite in places, with moments between characters sometimes strained in order to generate the necessary action. </p>
<p>This includes two subplots Spielberg and team wisely cut from the film. </p>
<p>The first involves a murky connection between Mayor Vaughn and the Mob that is partly responsible for his desire to keep the beaches open, despite Brody’s warnings. It seems both underdeveloped – we don’t find out much about it – and strangely present, with the majority of the novel’s scenes involving the mayor gesturing towards it. </p>
<p>The second, which probably would have been fatal to the film, involves an affair between Brody’s wife Ellen and Matt Hooper. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/guide-to-the-classics-moby-dick-by-herman-melville-52000">Guide to the classics: Moby-Dick, by Herman Melville</a>
</strong>
</em>
</p>
<hr>
<h2>Characters ‘loathsome in places’</h2>
<p>One of the great joys of the film is the developing friendship between Hooper and Brody, culminating in their delightful final exchange. After the shark is dead and they are kicking their way back to shore, Brody laughs: “I used to hate the water.” Hooper replies, “I can’t imagine why”. Both men are happy to have survived, and to have each other. </p>
<p>In the novel, it’s more or less hate at first sight, with Brody immediately resenting Hooper because he grew up as a “summer person” in the area. Brody is ashamed he’s not one of the wealthy summer people, and tries to hide this through a kind of pathetic machismo, which emerges most visibly in his competitiveness with Hooper. </p>
<p>This obsession with summer people defines much of the dialogue between Brody and Ellen, with Brody’s resentment of the summer people’s nonchalant and emasculating wealth matched by Ellen’s resentment of the fact she used to be a summer person before she married this oaf of a police chief.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=880&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=880&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=880&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1106&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1106&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565548/original/file-20231213-23-ko2crz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1106&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<p>The characters in the novel are thus thoroughly unappealing – even loathsome in places. Spielberg famously stated the shark was his favourite character in the novel. </p>
<p>The film’s Brody, anchored by the effortless charisma of Roy Scheider, is a steadfast, stoic working man who loves his wife and children and isn’t ashamed to show it in a gentle, unassuming way. </p>
<p>In the novel, Brody is “jealous and injured, inadequate and outraged”, a chauvinistic beer-guzzling bully, an obsessive – and often self-loathing – jerk. One of our first forays into his consciousness makes this immediately apparent: </p>
<blockquote>
<p>Sometimes during the summer, Brody would catch himself gazing with idle lust at one of the young, long-legged girls who pranced around town – their untethered breasts bouncing beneath the thinnest of cotton jerseys. But he never enjoyed the sensation, for it always made him wonder whether Ellen felt the same stirring when she looked at the tanned, slim young men who so perfectly complemented the long-legged girls.</p>
</blockquote>
<p>Ellen is also much less sympathetic in the novel (though admittedly in the film she’s a cardboard cutout of virtuous motherhood and wifedom). </p>
<p>She moves around as a shell of a person, a terrible snob disappointed by her social status and too embarrassed and ashamed to do anything about it, “tortured by thoughts she didn’t want to think – thoughts of chances missed and lives that could have been”. Like Brody, she is drowning in self-loathing: </p>
<blockquote>
<p>She made sure that everyone she met knew she had started her Amity life on an entirely different plane. She was aware of what she was doing, and she hated herself for it, because in fact she loved her husband deeply, adored her children, and – for most of the year – was quite content with her lot.</p>
</blockquote>
<p>The Hooper of the novel is similarly transformed by the film from an arrogant show-off, vaingloriously pursuing fame as a scientist at the expense of everything else, into a smart, responsible and energetic ball of fun, fully embodied by dynamo actor Richard Dreyfuss. </p>
<p>Only Quint – the mythical, Ahab-esque hunter (“Brody saw fever in Quint’s face – a heat that lit up his dark eyes, an intensity that drew his lips back from his teeth in a crooked smile”) – remains fundamentally unchanged, even though his unyielding brutality seems more appealing in the novel than in the film, with Robert Shaw portraying him as an antisocial maniac. </p>
<p>This revision includes the whole dynamic of the Brody family. The delightful moments between the kids and their parents, reflecting Spielberg’s superpower as a director (his talent for bringing sentimental family moments to life), are absent from the novel. </p>
<p>There’s something depressing about Brody’s relationship with his family. He has virtually no interaction with his children, and when he does, it’s like this: </p>
<blockquote>
<p>The oldest boy, Billy, lay on the couch, leaning on an elbow. Martin, the middle son, age twelve, lounged in an easy chair, his shoeless feet propped up on the coffee table. Eight-year-old Sean sat on the floor, his back against the couch, stroking a cat in his lap. “How goes it?” said Brody. “Good, Dad,” said Bill, without shifting his gaze from the television.</p>
</blockquote>
<h2>Is ‘easy to swallow’ better?</h2>
<p>Of course, populating a novel with unlikable characters and depressing family scenes is not a problem in and of itself. Popeye from William Faulkner’s <a href="https://www.penguin.com.au/books/sanctuary-9780099541028">Sanctuary</a> is hardly likeable, neither is pompous Nick Carraway from <a href="https://www.penguin.com.au/books/the-great-gatsby-9781784877088">The Great Gatsby</a> – and you’d be hard pressed to find a Dickens novel that doesn’t feature some degree of family strife. </p>
<p>But in Jaws, a “man versus beast” tale, a melodramatic thriller, it creates a flat feeling: we don’t wholly mind the prospect of these characters being eaten by a shark. At the same time, Benchley – despite occasional flaws in the writing – does capture something of the dismal inconsistencies and banalities of being human. The complex self-loathing of the characters contrasts with the brutal and unthinking power – the genius for action and killing – of the shark. </p>
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<figcaption><span class="caption">Spielberg ‘buffed out the scratches’ in Bentley’s novel for his film.</span></figcaption>
</figure>
<p>The film redacts the frailties and faults of the characters, turning an adult (albeit imperfect) novel into family-friendly fodder. Spielberg took a low-key thriller doubling as a study of a small American community and turned it into the kind of blockbuster that would get people back into – and keep them in – cinemas. </p>
<p>It comes as no surprise that the film also excises much of the novel’s pointed class critique. Note, for example, this description of the summer people early in the book, the haves to the local have-nots: </p>
<blockquote>
<p>Privilege had been bred into them with genetic certainty. As their eyes were blue or brown, so their tastes and consciences were determined by other generations. They had no vitamin deficiencies, no sickle-cell anaemia. […] Their bodies were lean, their muscles toned by boxing lessons at age nine, riding lessons at twelve, and tennis lessons ever since. They had no body odour. When they sweated, the girls smelled faintly of perfume; the boys smelled simply clean.</p>
</blockquote>
<p>Most, I’m sure, would hold the novel up as an inferior work. At a technical level, they’d probably be right. But while it’s pretentious, it’s also much more ambitious than the film. </p>
<p>Is something easy to swallow necessarily better for the digestion? Only a shark could answer that. The novel is ugly in places. But where it works, it works at the level of great literature.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/surfers-share-their-waves-with-sharks-but-fear-not-193395">Surfers share their waves with sharks, but fear not</a>
</strong>
</em>
</p>
<hr>
<h2>Benchley’s novel lingers longer</h2>
<p>One of the outcomes of Jaws was at least a couple of generations of people who, if not exactly afraid to go back in the water, had a tendency to hum the film’s theme to themselves when wading into the surf alone. </p>
<p>Benchley, horrified by the bad rap his novel gave sharks, would go on to become an ecological activist focused on shark protection. In 2015, a shark was named after him: <a href="https://hakaimagazine.com/news/meet-new-ninja-lanternshark/">Etmopterus benchleyi</a>.</p>
<p>Benchley’s Jaws may not immediately grab one as easily as Spielberg’s, and it’s certainly not as technically accomplished. Its position in American literature is minor compared to the film’s in Hollywood cinema. </p>
<p>But despite – or, perhaps, because of – its flaws, the novel is worth reading at a time when the blockbuster has virtually decimated the middle of American cinema, churning out masses of pleasurably forgettable, interchangeable films that float like a thick slick of chum on the water’s surface.</p><img src="https://counter.theconversation.com/content/218519/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ari Mattes 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>Peter Benchley’s classic 1974 ‘man versus beast’ blockbuster novel doubled as a scathing critique of 1970s America. Spielberg’s film made its characters likeable – and its tone into a ‘grand adventure’.Ari Mattes, Lecturer in Communications and Media, University of Notre Dame AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2146882023-12-19T18:13:36Z2023-12-19T18:13:36ZShipwrecks 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>
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<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 AdministrationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2182672023-11-30T13:35:54Z2023-11-30T13:35:54ZDrone fishing in South Africa is a danger to sharks and may be unfair to other fishers – study<p>“Drone fishing” is a relatively recent innovation in the use of unmanned aerial vehicles. Some recreational anglers are using personal drones to fly baited lines into hard-to-reach areas of water, or to look for good fishing areas. </p>
<p>Recreational fishing is a popular sport and hobby in South Africa, which has a 2,850km shoreline. The most recent estimate of the number of marine shore based anglers is about <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1111/fme.12515">400,000</a>. </p>
<p>The group of researchers I’m part of, who study linefish (fish caught using hook and line) became aware over the past 10 years or so of the increased practice of drone fishing. This was in part thanks to recreational fishers approaching us with their concerns. </p>
<p>One of the concerns is that increases in the numbers of enthusiastic anglers and their ability to catch fish might have significant effects on fish stocks and other animals (such as birds) in coastal zones. Another is that drone fishing might intensify conflict between fisher groups competing for the same species. Aside from recreation, linefishing provides the primary source of <a href="https://www.tandfonline.com/doi/abs/10.2989/1814232X.2020.1824738">protein and income</a> for about 2,730 commercial fishers, 2,400 small-scale boat fishers and 30,000 small-scale shore-based fishers in South Africa. </p>
<p>We agreed the practice should be investigated, but faced a challenge: there was very little monitoring going on to provide data. </p>
<p>So we took an unconventional approach to our <a href="https://link.springer.com/article/10.1007/s13280-021-01578-y#Sec11">study</a>. We used publicly available online monitoring to estimate the growing interest, global extent and catch composition of drone fishing. This showed us that there had been a big (357%) spike in interest in drone fishing in 2016. There were also worrying indications of a threat to species of conservation concern in South Africa. </p>
<p>We then consulted commercial drone operators, legal researchers and others to get a more holistic view. Drone fishing has economic, political, legal, ecological and physiological implications. Based on this we made some recommendations for further research and monitoring, and shared them with fishing authorities.</p>
<p>The South African Department of Forestry, Fisheries and the Environment then released a <a href="https://www.dffe.gov.za/sites/default/files/legislations/publicnotices/25february2022motorisedequipment_recreationalangling.pdf">public notice</a> warning recreational anglers that the use of drones and other electronic devices is deemed illegal under the <a href="https://www.gov.za/documents/marine-living-resources-act-27-may-1998-0000">South African Marine Living Resources Act</a>.</p>
<p>The fishing drone companies that had already emerged are now struggling to survive. They have taken the department to <a href="https://www.saflii.org/za/cases/ZAGPPHC/2022/250.html">court</a> seeking clarity on the legality of using drones in fishing. The judgement on this case, which is currently in the appeal court, will no doubt pave the way for how drone fishing is managed in South Africa in the future.</p>
<h2>Innovative research methods</h2>
<p>Largely because we were house-bound during the 2020-2021 COVID-19 pandemic we gathered most of our data via the internet. We surveyed social media platforms for drone-fishing dedicated groups and used Google Trends to track internet searches for “drone fishing”.</p>
<p>Results indicated a 357% spike in interest in 2016, after the release of a popular YouTube <a href="https://www.youtube.com/watch?v=8sdUZqOoAq4">video</a> of an angler catching a large longfin tuna from an Australian beach using a drone. The search volume increased to about 3,600 monthly searches from an average of about 1,400 before the peak. “Drone fishing” Facebook groups had over 17,000 members and 38,700 videos with titles including the term “drone fishing” had been uploaded. </p>
<p>The online interest was mostly in three countries: New Zealand, South Africa and Australia. </p>
<p>To get an idea of which fish species were targeted, we then watched 100 YouTube videos posted by drone fishers in those three countries. In both New Zealand and Australia, the most frequently observed catch was red snapper, which is not a species of direct conservation concern. In South Africa, though, sharks made up the majority (97%) of viewed catches, many of which are of severe conservation concern, such as the <a href="https://www.iucnredlist.org/species/3852/2872747">dusky shark</a>. </p>
<h2>Impacts of drone fishing</h2>
<p>Having established interest in and the presence of drone fishing in South Africa, we sought to consider the issue holistically – its impact on:</p>
<ul>
<li><p>targeted fish and their habitats</p></li>
<li><p>other animals in the coastal zone</p></li>
<li><p>other people using the coastal zone.</p></li>
</ul>
<p>Drones with cameras allow anglers to <a href="https://www.instagram.com/reel/Cz8sBz7ihYb/?igshid=MTc4MmM1YmI2Ng%3D%3D">identify</a> ideal fishing habitats far from the shore. Areas that anglers couldn’t reach before are now open to exploitation. Even fish that are released are less likely to survive when caught further offshore. A large fish hooked hundreds of metres offshore is likely to experience <a href="https://www.int-res.com/articles/meps2013/496/m496p207.pdf?">extreme exhaustion and physiological disturbance</a> and may be consumed by other predators. </p>
<p>The potential loss of fishing tackle by drone anglers is also a concern. It is common to lose tackle, either when it gets stuck in rocky habitats or while fighting large fish such as sharks. Both scenarios may result in hundreds of metres of fishing line remaining in the ocean. In addition to polluting the marine environment, such debris threatens to entangle birds, marine mammals and turtles. </p>
<p>In South Africa, drone fishing is only accessible to affluent anglers. Their increased catches might lead to conflict with fishers who depend on their catch for food or income.</p>
<p>It’s also possible that sharing live information on fishing conditions via the internet could add to concerns about the privacy of other public beach users.</p>
<p>Our 2021 <a href="https://link.springer.com/article/10.1007/s13280-021-01578-y#Sec11">paper</a> noted that at the time, there were no specific regulations relating to drone fishing in any country, including South Africa. We drew attention to legislation that could be used indirectly to regulate the practice. </p>
<h2>Regulation and management of fisheries</h2>
<p>Three of the paper’s co-authors were part of a working group for the South African Department of Forestry, Fisheries and the Environment. We shared the paper with the department and in 2022, it took concrete action on this issue for the first time. </p>
<p>The department released a <a href="https://www.dffe.gov.za/sites/default/files/legislations/publicnotices/25february2022motorisedequipment_recreationalangling.pdf">public notice</a> which explicitly prohibits drones and other remotely operated vehicles for angling. </p>
<p>Companies that custom build fishing drones were granted <a href="https://www.gov.za/speeches/use-motorised-equipment-recreational-angling-drones-and-remotely-operated-devices-and-or">leave to appeal</a> the original court ruling on their application to unban drone fishing. The appeal has not yet been heard.</p>
<p>We hope the end result will be better monitoring and management of South African recreational fishery, so that resources are available to those who need them the most.</p><img src="https://counter.theconversation.com/content/218267/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Claus Winkler 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>Increased interest in recreational fishing with drones has led to concern about its environmental and social impact.Alexander Claus Winkler, Research Associate, Rhodes UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2162542023-11-14T13:25:27Z2023-11-14T13:25:27ZPFAS ‘forever chemicals’ are getting into ocean ecosystems, where dolphins, fish and manatees dine – we traced their origins<p>PFAS, the “forever chemicals” that have been raising health concerns across the country, are not just a problem in drinking water. As these chemicals leach out of <a href="https://doi.org/10.1016/j.scitotenv.2015.12.081">failing septic systems</a> and <a href="https://doi.org/10.1016/j.watres.2021.117983">landfills</a> and wash off <a href="https://doi.org/10.1016/j.scitotenv.2021.150393">airport runways</a> and <a href="https://doi.org/10.1016/j.jhazmat.2022.129264">farm fields</a>, they can end up in streams that ultimately discharge into ocean ecosystems where fish, dolphins, manatees, sharks and other marine species live.</p>
<p>We study the risks from these persistent pollutants in coastal environments as <a href="https://scholar.google.com/citations?user=z697KEMAAAAJ&hl=en">environmental</a> <a href="https://scholar.google.com/citations?user=w3It4CgAAAAJ&hl=en">analytical chemists</a> at Florida International University’s Institute of the Environment.</p>
<p>Because PFAS can <a href="https://doi.org/10.1016/j.envint.2022.107640">enter the food chain</a> and accumulate in marine plants and animals, including fish that humans eat, the spread of these chemicals has <a href="https://doi.org/10.1016/j.envres.2022.115165">ecological</a> and <a href="https://doi.org/10.1016/j.scitotenv.2022.155316">human health</a> implications. </p>
<figure class="align-center ">
<img alt="Reef fish in Biscayne Bay." src="https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558906/original/file-20231111-17-ata3gl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Biscayne Bay and nearby coastal areas are teeming with fish, including many varieties that people eat.</span>
<span class="attribution"><a class="source" href="https://www.nps.gov/media/photo/gallery-item.htm?pg=898241&id=ccce1eac-1dd8-b71b-0bc0-d80f536c707c&gid=CA49F0A1-1DD8-B71B-0B6B1F1948BFA884">NPS image by Shaun Wolfe</a></span>
</figcaption>
</figure>
<p>In a new study, we <a href="https://doi.org/10.1016/j.scitotenv.2023.168413">traced the origins of PFAS contamination</a> in Miami’s <a href="https://doi.org/10.1007/s11356-022-21589-w">Biscayne Bay</a> to help pinpoint ways to reduce the harm.</p>
<h2>What are PFAS?</h2>
<p>PFAS – perfluoroalkyl and polyfluoroalkyl substances – are a group of human-made contaminants that have been <a href="https://theconversation.com/what-are-pfas-the-forever-chemicals-showing-up-in-drinking-water-an-environmental-health-scientist-explains-185015">used for over 50 years</a>. They’re found in personal care products, such as cosmetics and shampoo, and in water-repellent coatings for nonstick cookware and food packaging. They’re also used in adhesives and aqueous firefighting foams, among other products.</p>
<p>As those PFAS-containing products washed down drains and were thrown in landfills over the years, PFAS chemicals became widespread in the environment. Eventually, these chemicals found their way into aquatic ecosystems, including surface water, groundwater and coastal environments.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=534&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=534&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558904/original/file-20231111-15-iq9oxm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=534&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An illustration shows some of the sources of PFAS in the environment.</span>
<span class="attribution"><a class="source" href="https://scdhec.gov/environment/polyfluoroalkyl-substances-pfas">North Carolina Department of Health and Environmental Control</a></span>
</figcaption>
</figure>
<p>The same stability and resistance to degrading that makes these chemicals valuable for water- and stain-proof products also makes them nearly impossible to destroy. Hence, the nickname “forever chemicals.” They persist in the environment for decades to centuries.</p>
<p>That’s a problem, because PFAS have been linked to <a href="https://doi.org/10.1038/s41370-018-0097-y">immunological disorders</a>, endocrine, developmental, reproductive and neurological disruption and increased risk of bladder, <a href="https://doi.org/10.1007/s00204-020-02808-0">liver</a>, <a href="https://doi.org/10.1093/jnci/djaa143">kidney</a> and <a href="https://doi.org/10.1289/EHP12603">testicular cancer</a>. A drinking water study by the U.S. Geological Survey estimated these chemicals were in <a href="https://www.usgs.gov/news/national-news-release/tap-water-study-detects-pfas-forever-chemicals-across-us">at least 45% of tap water</a> across the U.S., and a large percentage of Americans are now believed to have <a href="https://www.niehs.nih.gov/health/topics/agents/pfc/index.cfm">PFAS detectable in their blood</a>.</p>
<p>Studies have also found PFAS in a broad range of <a href="https://doi.org/10.1016/j.envint.2022.107640">marine wildlife</a>, including in the livers of otters and in gulls’ eggs, as well as <a href="https://doi.org/10.1016/j.envres.2022.115165">in freshwater fish</a> across the U.S. These chemicals have already been shown to affect the <a href="https://doi.org/10.1016/j.envint.2019.105358">immune system and liver function of fish</a> and <a href="https://doi.org/10.1016/j.envint.2015.10.007">marine mammals</a>.</p>
<h2>How PFAS get into the marine environment</h2>
<p>When we began tracking the sources of PFAS in Biscayne Bay, we found hot spots of these chemicals around the exits of urban canals – especially the Miami River, Little River and Biscayne Canal. Each of these canals, we found, is a <a href="https://doi.org/10.1016/j.scitotenv.2023.168413">major point source</a> contributing to the presence of PFAS in offshore areas of the Atlantic Ocean.</p>
<p>One major source of that PFAS is sewage contamination from failed septic systems and wastewater leaks in urban areas. This is evident by the presence of the types of PFAS – such as PFOS, PFOA, PFPeA, PFHxS, PFHxA, PFBA and PFBS – that <a href="https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=345065">are used as</a> stain and grease repellents and in carpets, food packaging materials and household products.</p>
<p>Another major source is represented by the predominance of <a href="https://doi.org/10.1093/toxsci/kfad006">6-2 FTS</a> in the Miami River – 6-2 FTS is a fluorotelomer PFAS typically used in aqueous film-forming foam found at military and airport facilities. The Miami River flows past rail yards, industries and Miami International Airport on its way to Biscayne Bay.</p>
<figure class="align-center ">
<img alt="A map of Miami's Biscayne Bay and nearby coastal areas that were sampled. The hot spots stand out clearly near canal exits." src="https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=847&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=847&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=847&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1065&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1065&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558902/original/file-20231111-17-le8qtk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1065&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A map from the study shows PFAS hot spots near canals that carry water from the city. Red indicates higher PFAS concentrations, measured in nanograms per liter. Green indicates lower, more diluted PFAS concentrations.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We also used a model to predict how ocean currents would disperse PFAS coming out of those canals and into coastal areas. We found that the PFAS concentrations were highest close to the canals, decreased along the bay and declined as ocean water became deeper and more saline, which makes PFAS less soluble in water. </p>
<p>Overall, PFAS concentrations were almost <a href="https://doi.org/10.1016/j.scitotenv.2023.168413">six times higher</a> in surface waters near land compared with deep-water samples collected 13 to 33 feet (4 to 10 meters) below the surface in the bay and offshore. That suggests the highest risk is to pelagic fish that hang out in surface waters, such as mackerel, tunas and mahi-mahi.</p>
<h2>How marine organisms are at risk</h2>
<p>The <a href="https://doi.org/10.1016/j.scitotenv.2023.168413">levels of PFOS and PFOA</a> in our study were below the Florida Department of Environmental Protection advisory levels in surface water for human health exposure. However, the advisory levels might not be protective of human and marine life. </p>
<p>They do not take into consideration that these chemicals accumulate <a href="https://doi.org/10.1016/j.jhazmat.2022.128602">through the food chain</a>. Higher concentration in the top of the food web means PFAS could pose a greater <a href="https://doi.org/10.1016/j.chemosphere.2009.07.079">risk to dolphins</a>, sharks and humans <a href="https://doi.org/10.1021/acs.est.3c00374">that consume fish</a>.</p>
<figure class="align-center ">
<img alt="A man leans over the edge of a boat holding a rope attached to sampling devices that are in the water below." src="https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=457&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=457&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=457&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=574&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=574&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558903/original/file-20231111-21-a6fbtm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=574&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Olutobi Daniel Ogunbiyi, an author of this article and lead author of the study, takes water samples in Biscayne Bay.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Many types of PFAS identified in our samples are not regulated, and their potential toxicity is unknown. We believe there is a need for federal and state agencies to develop guidelines and implement action plans to protect people and the aquatic life in Biscayne Bay.</p>
<h2>What you can do about it</h2>
<p>Given the persistence of PFAS and their widespread use, it is not surprising that these forever chemicals are found in almost all water systems in South Florida and are showing up <a href="https://doi.org/10.1016/j.scitotenv.2020.143297">in coastal waters around the world</a>.</p>
<p>While scientists look for effective and efficient ways to eliminate and remove these chemicals from water, food and the environment, people can limit their use of PFAS-containing products to reduce the amounts of these chemicals that get into the marine environment.</p>
<p>Here are some <a href="https://www.fda.gov/food/process-contaminants-food/authorized-uses-pfas-food-contact-applications">common products that contain PFAS</a> to watch for: Teflon nonstick cookware; food packaging for fast food and popcorn; water-resistant clothing and cosmetics; and treated carpets.</p><img src="https://counter.theconversation.com/content/216254/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Natalia Soares Quinete receives funding from National Science Foundation.</span></em></p><p class="fine-print"><em><span>Olutobi Daniel Ogunbiyi receives funding from the National Science Foundation awarded through FIU Institute of Environment and Center for Research and Excellence in Science and Tech. </span></em></p>Scientists found PFAS hot spots in Miami’s Biscayne Bay where the chemicals are entering coastal waters and reaching the ocean. Water samples point to some specific sources.Natalia Soares Quinete, Assistant Professor of Chemistry, Florida International UniversityOlutobi Daniel Ogunbiyi, Ph.D. Candidate in Chemistry, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2140702023-10-26T22:55:00Z2023-10-26T22:55:00ZBringing a shark to a knife fight: 7,000-year-old shark-tooth knives discovered in Indonesia<figure><img src="https://images.theconversation.com/files/555981/original/file-20231026-37260-5cxl3t.jpg?ixlib=rb-1.1.0&rect=31%2C31%2C5083%2C3414&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/tiger-shark-jaw-showing-teeth-343934774">Matthew R McClure/Shutterstock</a></span></figcaption></figure><p>Excavations on the Indonesian island of Sulawesi have uncovered two unique and deadly artefacts dating back some 7,000 years – tiger shark teeth that were used as blades.</p>
<p>These finds, reported in the journal <a href="https://doi.org/10.15184/aqy.2023.144">Antiquity</a>, are some of the earliest archaeological evidence globally for the use of shark teeth in composite weapons – weapons made with multiple parts. Until now, the oldest such shark-tooth blades found were less than 5,000 years old.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photos of two bone shards with a serrated edge and holes along the bottom" src="https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550157/original/file-20230926-23-g9d5se.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Modified tiger shark teeth found in 7,000-year-old layers of Leang Panninge (top) and Leang Bulu’ Sipong 1 (bottom) on the Indonesian island of Sulawesi.</span>
<span class="attribution"><span class="source">M.C. Langley</span></span>
</figcaption>
</figure>
<p>Our international team used a combination of scientific analysis, experimental reproduction and observations of recent human communities to determine that the two modified shark teeth had once been attached to handles as blades. They were most likely used in ritual or warfare.</p>
<h2>7,000-year-old teeth</h2>
<p>The two shark teeth were recovered during excavations as part of a joint Indonesian-Australian archaeological research program. Both specimens were found in archaeological contexts attributed to the <a href="https://theconversation.com/who-were-the-toaleans-ancient-womans-dna-provides-first-evidence-for-the-origin-of-a-mysterious-lost-culture-166565">Toalean culture</a> – an enigmatic foraging society that lived in southwestern Sulawesi from around 8,000 years ago until an unknown period in the recent past.</p>
<p>The shark teeth are of a similar size and came from <a href="https://oceana.org/marine-life/tiger-shark/">tiger sharks</a> (<em>Galeocerda cuvier</em>) that were approximately two metres long. Both teeth are perforated.</p>
<p>A complete tooth, found at the cave site of Leang Panninge, has two holes drilled through the root. The other – found at a cave called Leang Bulu’ Sipong 1 – has one hole, though is broken and likely originally also had two holes.</p>
<p>Microscopic examination of the teeth found they had once been tightly fixed to a handle using plant-based threads and a glue-like substance. The adhesive used was a combination of mineral, plant and animal materials.</p>
<p>The same method of attachment is seen on modern shark-tooth blades used by cultures throughout the Pacific.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up photo of a pointy yellow tooth tooth with scratches clearly visible" src="https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=598&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=598&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555969/original/file-20231026-32800-1mgf8c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=598&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scratches and a ground section on the tip of the Leang Panninge shark tooth indicate its use by people 7,000 years ago.</span>
<span class="attribution"><span class="source">M.C. Langley</span></span>
</figcaption>
</figure>
<p>Examination of the edges of each tooth found they had been used to pierce, cut and scrape flesh and bone. However, far more damage was present than a shark would naturally accrue during feeding.</p>
<p>While these residues superficially suggest Toalean people were using shark-tooth knives as everyday cutting implements, ethnographic (observations of recent communities), archaeological and experimental data suggest otherwise.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A brownish yellow bone close up with holes and grooves clearly visible" src="https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=264&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=264&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=264&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=332&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=332&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555970/original/file-20231026-30-epfmyw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=332&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Grooves and traces of red resin along the base of the Leang Panninge tooth show how the teeth were attached using threads.</span>
<span class="attribution"><span class="source">M.C. Langley</span></span>
</figcaption>
</figure>
<h2>Why use shark teeth?</h2>
<p>Not surprisingly, our experiments found tiger shark-tooth knives were equally effective in creating long, deep gashes in the skin when used to strike (as in fighting) as when butchering a leg of fresh pork.</p>
<p>Indeed, the only negative aspect is that the teeth blunt relatively quickly – too quickly to make their use as an everyday knife practical.</p>
<p>This fact, as well as the fact shark teeth can inflict deep lacerations, probably explains why shark-tooth blades were restricted to weapons for conflict and ritual activities in the present and recent past.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/evolution-of-a-smile-400-million-year-old-spiny-fish-overturns-shark-theory-of-tooth-origins-160563">Evolution of a smile: 400 million year old spiny fish overturns shark theory of tooth origins</a>
</strong>
</em>
</p>
<hr>
<h2>Shark-tooth blades in recent times</h2>
<p>Numerous societies across the globe have integrated shark teeth into their material culture. In particular, peoples living on coastlines (and actively fishing for sharks) are more likely to incorporate greater numbers of teeth into a wider range of tools.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three serrated implements with neat rows of pointy teeth attached" src="https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=667&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=667&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=667&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=838&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=838&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550163/original/file-20230926-28-azgt97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=838&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 teeth are widely used to edge deadly combat weapons or powerful ritual blades in the Pacific. Left: a knife from Kiribati; centre and right: weapons from Hawai'i.</span>
<span class="attribution"><a class="source" href="https://www.britishmuseum.org/collection/search?keyword=shark&keyword=tooth&keyword=knife">The Trustees of The British Museum</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Observations of present-day communities indicate that, when not used to adorn the human body, shark teeth were almost universally used to create blades for conflict or ritual – including ritualised combat.</p>
<p>For example, a fighting knife found throughout north Queensland has a single long blade made from approximately 15 shark teeth placed one after the other down a hardwood shaft shaped like an oval, and is used to strike the flank or buttocks of an adversary. </p>
<p>Weapons, including lances, knives and clubs armed with shark teeth are known from mainland New Guinea and Micronesia, while lances form part of the mourning costume in Tahiti. </p>
<p>Farther east, the peoples of Kiribati are renowned for their shark-tooth daggers, swords, spears and lances, which are recorded as having been used in highly ritualised and often fatal conflicts.</p>
<p>Shark teeth found in Maya and Mexican archaeological contexts are widely thought to have been used for ritualised bloodletting, and shark teeth are known to have been used as tattooing blades in Tonga, Aotearoa New Zealand, and Kiribati. </p>
<p>In Hawai‘i, so-called “shark-tooth cutters” were used <a href="https://www.jstor.org/stable/20702769">as concealed weapons and for</a> “cutting up dead chiefs and cleaning their bones preparatory to the customary burials”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A wooden weapon with a rounded handle and jagged tooth attachments at the other end" src="https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=379&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=379&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550167/original/file-20230926-18-o9w9uq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=379&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 shark-tooth knife from Aua Island, Papua New Guinea. Red arrows highlight wear and damage caused by fighting.</span>
<span class="attribution"><span class="source">M. Langley and The University of Queensland Anthropology Museum</span></span>
</figcaption>
</figure>
<h2>Other shark tooth archaeological finds</h2>
<p>Almost all shark-tooth artefacts recovered globally have been identified as adornments, or interpreted as such.</p>
<p>Indeed, modified shark teeth have been recovered from older contexts. A solitary tiger shark tooth with a single perforation from Buang Merabak (New Ireland, Papua New Guinea) is dated to around 39,500–28,000 years ago. Eleven teeth with single perforations from Kilu (Buka Island, Papua New Guinea) are dated to around 9,000–5,000 years ago. And an unspecified number of teeth from Garivaldino (Brazil) is dated to around 9,400–7,200 years ago.</p>
<p>However, in each of these cases the teeth were likely personal ornaments, not weapons.</p>
<p>Our newly described Indonesian shark tooth artefacts, with their combination of modifications and microscopic traces, instead indicate they were not only attached to knives, but very likely linked to ritual or conflict.</p>
<p>Whether they cut human or animal flesh, these shark teeth from Sulawesi could provide the first evidence that a distinctive class of weaponry in the Asia-Pacific region has been around much longer than we thought.</p><img src="https://counter.theconversation.com/content/214070/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Langley is an Associate Professor of Archaeology in the Australian Research Centre for Human Evolution at Griffith University, Brisbane. She receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Adam Brumm receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Adhi Oktaviana is a PhD Candidate at Griffith Centre for Social and Cultural Research, Griffith University, Gold Coast and Researcher at Research Centre of Archaeometry, The National Research and Innovation Agency, Jakarta</span></em></p><p class="fine-print"><em><span>Lecturer in the archeology study program, Hasanuddin University and Chair of the Sulawesi Archaeological Research Collaboration Center. </span></em></p><p class="fine-print"><em><span>Basran Burhan is a PhD student at Australian Research Centre for Human Evolution at Griffith University, Brisbane. </span></em></p>Archaeologists have discovered two 7,000-year-old tiger shark teeth that were once part of ritual or fighting blades on the Indonesian island of Sulawesi.Michelle Langley, Associate Professor of Archaeology, Griffith UniversityAdam Brumm, Professor, Griffith UniversityAdhi Oktaviana, PhD Candidate, Griffith UniversityAkin Duli, Professor, Universitas HasanuddinBasran Burhan, PhD candidate, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2132582023-10-16T01:38:40Z2023-10-16T01:38:40ZCritically endangered scalloped hammerheads gather in seas off Perth. They need protection<figure><img src="https://images.theconversation.com/files/553890/original/file-20231016-18-xqswws.jpg?ixlib=rb-1.1.0&rect=0%2C26%2C5991%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Unlike nearly every other species of shark, scalloped hammerheads are highly social. They gather in large groups, or aggregations, numbering in the hundreds. But why? We don’t know. </p>
<p>With the help of drones, we now know a bit more. In our <a href="https://doi.org/10.1093/icesjms/fsad153">new research</a>, we describe finding a location in a marine park off the coast of Perth where juvenile scalloped hammerheads (<em>Sphyrna lewini</em>) gather in numbers. </p>
<p>Scalloped hammerheads – one of ten species in the hammerhead family – prefer warm waters. But they have become regular visitors to the waters off Perth in summer, now the <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/aec.13149">southernmost part</a> of their range. The sharks are not considered dangerous to humans. </p>
<p>These iconic sharks are among the world’s <a href="https://www.iucnredlist.org/species/39385/2918526">most threatened species</a> due to over-fishing. And incredibly they are still legally fished in <a href="https://www.abc.net.au/news/2022-03-28/nt-hammerhead-sharks-tighter-fishing-rules/100930138">Australia</a>, despite their populations falling by 80% in just 55 years. </p>
<p>They are in danger unless we protect them. </p>
<h2>What’s special about these oceanic wayfarers?</h2>
<p><a href="https://www.fishbase.se/summary/912#:%7E:text=This%20hammerhead%20shark%20is%20distinguished,posterior%20to%20or%20nearly%20opposite">Scalloped hammerheads</a> are named for the dents on their hammer-shaped head or <a href="https://theconversation.com/why-do-hammerhead-sharks-have-hammer-shaped-heads-184372">cephalofoil</a>. They’re skilled long-distance swimmers and exceptional <a href="https://www.science.org/doi/10.1126/science.add4445#:%7E:text=Scalloped%20hammerhead%20sharks%20occupy%20warm,diets%20(12%E2%80%9318).">free divers</a>, able to hunt in the dark waters 500 metres below the surface. They grow slowly and live for up to 55 years. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-hammerhead-sharks-have-hammer-shaped-heads-184372">Why do hammerhead sharks have hammer-shaped heads?</a>
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</em>
</p>
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<p>They’re a challenging species to study because they cover long distances and spend lots of time down deep. Finding a place where these sharks regularly aggregate offers us a remarkable opportunity to learn more about these oceanic wayfarers.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&rect=0%2C2%2C1917%2C1074&q=45&auto=format&w=1000&fit=clip"><img alt="A school of scalloped hammerhead sharks in shallow seas" src="https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&rect=0%2C2%2C1917%2C1074&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553422/original/file-20231012-21-jof197.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">From our drones, we could watch as the scalloped hammerheads grouped together each month.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>How did we find them?</h2>
<p>Small commercial drones <a href="https://www.mdpi.com/2504-446X/5/1/8">are revolutionising</a> the way we study marine wildlife – especially sharks. The aerial perspective lets us see things we couldn’t see before. Drones have shed light on <a href="https://theconversation.com/humpback-whales-have-been-spotted-bubble-net-feeding-for-the-first-time-in-australia-and-we-have-it-on-camera-157355">elusive behaviours</a> we have otherwise been unable to verify. Footage can also be used to identify, count and measure animals.</p>
<p>We heard surf lifesavers had observed hammerhead sharks off Perth beaches during their helicopter shark patrols. We began our search at the <a href="https://exploreparks.dbca.wa.gov.au/park/shoalwater-islands-marine-park">Shoalwater Islands Marine Park</a>, off the coast from Rockingham, in Perth’s southern suburbs. </p>
<p>Over two successive summers, we used drones to successfully spot and then track scalloped hammerheads as they aggregated inside the marine park. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of Perth's shoalwater islands marine park. Image shows shallow waters, land and sand" src="https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=275&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=275&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=275&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=345&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=345&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551983/original/file-20231004-21-xyon8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=345&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 juvenile sharks aggregate in the shallow waters of the Shoalwater Islands Marine Park, south of Perth.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>What did we learn?</h2>
<p>We learned many things. First, the scalloped hammerheads aggregating at the marine park were juveniles, not adults. </p>
<p>We only found them in a small area of the marine park. They were present with the full moon. </p>
<p>Once aggregated, they would swim in formation, moving in winding patterns through the shallow waters of the marine park. </p>
<p>In terms of what were they doing, our study suggest they’re seeking a place to rest and recover. Sharks often hunt more on the nights with a full moon, taking advantage of better light to see prey. </p>
<p>That would mean these juveniles are tired after a night’s hunting. Now they need to rest and digest. Gathering in a group could also provide some degree of protection from other predators in the area. </p>
<p>It’s likely, therefore, these shallow waters are important shelter for scalloped hammerheads.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up of a scalloped hammerhead shark filmed by a robotic camera underwater" src="https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551982/original/file-20231004-27-gnonhe.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=427&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This scalloped hammerhead was filmed by a baited remote underwater video system (BRUVS) off the Cocos Keeling Islands, Western Australia.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>How can we protect them?</h2>
<p>Our research points to the urgent need to strengthen protection of scalloped hammerheads in the popular Shoalwater Islands Marine Park. </p>
<p>We need a code of conduct to prevent water users such as boaters, kayakers, and swimmers from disturbing the animals, similar to those protecting <a href="https://ningaloo-atlas.org.au/node/371">whale sharks</a> and <a href="https://www.agriculture.gov.au/sites/default/files/documents/aust-national-guidelines-whale-dolphin-watching-2017.pdf">humpback whales</a>. Boat speed limits and bans on chasing animals are essential if we are to protect these endangered animals.</p>
<p>Stopping fishing at the aggregation site is vitally important. Hammerheads are <a href="https://www.int-res.com/articles/meps2013/496/m496p207.pdf">extremely vulnerable to any capture</a> and are unlikely to survive “catch and release” fishing. The marine park should be a safe spot for the sharks to shelter and rest.</p>
<p>We need to strengthen protections in the marine park, shifting from multiple use status – which allows fishing – to highly protected, which prohibits fishing. </p>
<p>Right now, the federal government is reviewing the status of these sharks. Given ongoing fishing pressure, there are clear reasons to assess them as endangered rather than their unclear status as “<a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=85267">conservation dependent</a>”.</p>
<p>Australia is fortunate to host remarkable and endangered species such as hammerhead sharks. As our understanding grows, so does our responsibility. There are simple steps available to the state and federal government to safeguard the future of this threatened species and maintain healthy marine ecosystems. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/some-sharks-have-declined-by-92-in-the-past-half-century-off-queenslands-coast-108742">Some sharks have declined by 92% in the past half-century off Queensland's coast</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/213258/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Naima Andrea López received funding for her PhD research from the Australian Government RTP Scholarship, The Jock Clough Marine Foundation through the Oceans Institute Robson and Robertson Award and The Holsworth Wildlife Research Endowment & The Ecological Society of Australia. </span></em></p><p class="fine-print"><em><span>Jessica Meeuwig 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>Scalloped hammerheads pose no risk to us – but we pose enormous risk to them. Our discovery of a large new aggregation gives us an opportunity to protect these animals.Naima Andrea López, Postdoctoral Research Fellow, The University of Western AustraliaJessica Meeuwig, Wen Family Chair in Conservation, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2122112023-09-07T13:30:48Z2023-09-07T13:30:48ZSouth Africa’s great white sharks are changing locations – they need to be monitored for beach safety and conservation<p>South Africa is renowned for having one of the world’s biggest populations of great white sharks (<em>Carcharodon carcharias</em>). Substantial <a href="https://www.science.org/content/article/great-white-sharks-have-suddenly-disappeared-one-their-favorite-hangouts">declines</a> have been observed, however, in places where the sharks normally gather on the coast of the Western Cape province. Sharks congregate at these locations to feed, interact socially, or rest. </p>
<p>In Cape Town, skilled “<a href="https://sharkspotters.org.za/safety/shark-sightings/#:%7E:text=Shark%20Sightings%20to%20Date%20Since%20the%20program%20began,over%202%2C020%20shark%20sightings%20on%20Shark%20Spotters%20beaches.">shark spotters</a>” documented a peak of over 300 great white shark sightings across eight beaches in 2011, but have recorded no sightings since 2019. These declines have sparked concerns about the overall conservation status of the species. </p>
<p>Conserving great white sharks is vital because they have a pivotal role in marine ecosystems. As top predators, they help maintain the health and balance of marine food webs. Their presence influences the behaviour of other marine animals, affecting the entire ecosystem’s structure and stability. </p>
<p>Marine biologists like us needed to know whether the decline in shark numbers in the Western Cape indicated changes in the whole South African population or whether the sharks had moved to a different location.</p>
<p>To investigate this problem, we undertook an extensive <a href="https://www.sciencedirect.com/science/article/pii/S1470160X23008622">study</a> using data collected by scientists, tour operators and shore anglers. We examined the trends over time in abundance and shifts in distribution across the sharks’ South African range. </p>
<p>Our investigation revealed significant differences in the abundance at primary gathering sites. There were declines at some locations; others showed increases or stability. Overall, there appears to be a stable trend. This suggests that white shark numbers have remained constant since they were given protection in 1991.</p>
<p>Looking at the potential change in the distribution of sharks between locations, we discovered a shift in human-shark interactions from the Western Cape to the Eastern Cape. More research is required to be sure whether the sharks that vanished from the Western Cape are the same sharks documented along the Eastern Cape.</p>
<p>The stable population of white sharks is reassuring, but the distribution shift introduces its own challenges, such as the risk posed by fisheries, and the need for beach management. So there is a need for better monitoring of where the sharks are.</p>
<h2>Factors influencing shark movements</h2>
<p>We recorded the biggest changes between 2015 and 2020. For example, at Seal Island, False Bay (Western Cape), shark sightings declined from 2.5 sightings per hour in 2005 to 0.6 in 2017. Shifting eastward to Algoa Bay, in 2013, shore anglers caught only six individual sharks. By 2019, this figure had risen to 59. </p>
<p>The changes at each site are complex, however. Understanding the patterns remains challenging. </p>
<p>These predators can live for more than 70 years. Each life stage comes with <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.811985/full?fbclid=IwAR3JnefKDynkDfRp0ffs2p6l9T1oRXdBJcVeIOLnd6FAV3BlcnSfzgQk8ig&utm_source=hoobe&utm_medium=page">distinct behaviours</a>: juveniles, especially males, tend to stay close to the coastline, while sub-adults and adults, particularly females, venture offshore.</p>
<p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0068554">Environmental factors</a> like water temperature, lunar phase, season and food availability further influence their movement patterns. </p>
<p>Changes in the climate and ocean over extended periods might also come into <a href="https://www.dailymaverick.co.za/article/2021-09-27-quest-for-elusive-white-shark-decades-ago-raises-questions-about-the-species-today/">play</a>. </p>
<p>As adaptable predators, they target a wide range of prey and thrive in a broad range of temperatures, with a preference for 14–24°C. Their migratory nature allows them to seek optimal conditions when faced with unfavourable environments.</p>
<h2>Predation of sharks by killer whales</h2>
<p>The movement complexity deepens with the involvement of <a href="https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2531">specialist killer whales with a taste for shark livers</a>. Recently, these apex predators have been observed preying on white, sevengill and bronze whaler sharks. </p>
<p>Cases were first documented in 2015 along the South African coast, coinciding with significant behavioural shifts in white sharks within Gansbaai and False Bay. </p>
<p>Although a direct cause-and-effect link is not firmly established, observations and tracking data support the notion of a distinct <a href="https://www.researchgate.net/profile/Simon-Elwen/publication/361638937_Fear_at_the_top_killer_whale_predation_drives_white_shark_absence_at_South_Africa's_largest_aggregation_site/links/62d4f7aba6abd57c6aeea4ed/Fear-at-the-top-killer-whale-predation-drives-white-shark-absence-at-South-Africas-largest-aggregation-site.pdf">flight response</a> among white sharks following confirmed predation incidents. </p>
<p>More recently, it was clear that in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10078210/">Mossel Bay</a>, when a killer whale pod killed at least three white sharks, the remaining sharks were prompted to leave the area. </p>
<h2>Survival and conservation of sharks</h2>
<p>The risk landscape for white sharks is complex. A <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.811985/full?fbclid=IwAR3JnefKDynkDfRp0ffs2p6l9T1oRXdBJcVeIOLnd6FAV3BlcnSfzgQk8ig&utm_source=hoobe&utm_medium=page">study</a> published in 2022 showed a notable overlap of white sharks with longline and gillnet fisheries, extending across 25% of South Africa’s Exclusive Economic Zone. The sharks spent 15% of their time exposed to these fisheries. </p>
<p>The highest white shark catches were reported in KwaZulu-Natal, averaging around 32 per year. This emphasised the need to combine shark movement with reliable catch records to assess risks to shark populations.</p>
<p>As shark movement patterns shift eastward, the potential change in risk must be considered. Increased overlap between white sharks, shark nets, drumlines (baited hooks) and gillnets might increase the likelihood of captures.</p>
<h2>Beach safety and management adaptation</h2>
<p>Although shark bites remain a <a href="https://sharkspotters.org.za/wp-content/uploads/2016/10/Curtis-et-al.-Responding-to-the-risk-of-white-shark-attack-sm.pdf">low risk</a>, changing shark movements could also influence beach safety. The presence of sharks can influence human activities, particularly in popular swimming and water sports areas. Adjusting existing shark management strategies might be necessary as distributions change. </p>
<p>Increased signage, temporary beach closures, or improved education about shark behaviour might be needed. </p>
<p>In Cape Town, for example, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185335">shark spotters</a> have adjusted their efforts on specific beaches. Following two <a href="https://www.newsweek.com/great-white-sharks-gather-site-fatal-attack-1749172">fatal shark incidents</a> in 2022, their programme expanded to <a href="https://www.bing.com/search?q=+plettenberg+bay+shark+spotters&qs=n&form=QBRE&sp=-1&lq=0&pq=+plettenberg+bay+shark+spotte&sc=7-29&sk=&cvid=FB5D782CE8BF476793D155E8B9C6B408&ghsh=0&ghacc=0&ghpl=">Plettenberg Bay</a>. Anecdotal evidence highlights additional Eastern Cape locations where surfers and divers encounter more white sharks than before.</p>
<h2>Enhanced monitoring and long-term programmes</h2>
<p>Further research is required to understand the factors behind the movements of sharks and their impact on distribution over space and time. Our study underscores the importance of standardising data collection methods to generate reliable abundance statistics across their entire range. Other countries suffer from the same problem.</p>
<p>Additionally, we propose establishing long-term monitoring programmes along the Eastern Cape and continuing work to reduce the number of shark deaths.</p>
<p><em>Sarah Waries, a master’s student and CEO of Shark Spotters in Cape Town, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/212211/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alison Kock works for South African National Parks. She is affiliated with the Top Predator Scientific Working Group of the Department of Forestry, Fisheries and the Environment and Shark Spotters. She received funding from the Save Our Seas Foundation for shark research.</span></em></p><p class="fine-print"><em><span>Alison Towner, Heather Bowlby, Matt Dicken, and Toby Rogers do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>South Africa’s white shark population is not in decline but migrating to survive.Alison Kock, Marine Biologist, South African National Parks (SANParks); Honorary Research Associate, South African Institute for Aquatic Biodiversity (SAIAB), South African Institute for Aquatic BiodiversityAlison Towner, Marine biologist, Rhodes UniversityHeather Bowlby, Research Lead, Fisheries and Oceans CanadaMatt Dicken, Adjunct Professor of Marine Biology, Nelson Mandela UniversityToby Rogers, PhD Candidate, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2115062023-09-04T02:35:55Z2023-09-04T02:35:55ZHow diving as a boy took Tim Flannery on the trail of the megalodon in all its ‘terrifying glory’<figure><img src="https://images.theconversation.com/files/545437/original/file-20230830-39956-lsjhr9.jpg?ixlib=rb-1.1.0&rect=77%2C11%2C3886%2C1970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tim Flannery with a model set of jaws of a megalodon at the Australian Museum, and, on right, a megalodon tooth.</span> <span class="attribution"><span class="source">Photos: Text Publishing, Wikimedia Commons</span></span></figcaption></figure><p>With <a href="https://www.imdb.com/title/tt9224104/">Meg 2: The Trench</a> currently showing in cinemas – its eponymous star looking unhelpfully like an oversized great white shark – megalodons are having another pop cultural moment.</p>
<p>Cinema-goers may, justifiably, have questions about the accuracy of this latest representation of these prehistoric creatures. The good news is that Tim and Emma Flannery have written a book that will both thrill and inform such curious readers.</p>
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<p><em>Review: Big Meg: The Story of the Largest and Most Mysterious Predator that Ever Lived – Tim Flannery and Emma Flannery (Text Publishing)</em></p>
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<p>Megalodons had cartilaginous structures, rather than the bony skeletons of the dinosaurs. While dinosaurs roamed Earth during the Triassic, Jurassic and Cretaceous periods (from 252 million to 66 million years ago), it is believed the megalodon emerged a mere 23 million years ago. </p>
<p>Megalodons had big, serrated teeth that could cut through large marine animals. When they became extinct, about 3.6 million years ago, palaeontologists were left only with remnants of their toothy smile from which to unpick the story of these sharks.</p>
<p>A palaeontologist by training, Tim Flannery’s prolific literary output has contributed both to academic debate and general awareness-raising about the nature and needs of the planet we continue to dominate. In this latest book, he has combined forces with his daughter, Emma, a scientist and explorer in her own right, but this is very much his story.</p>
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<p>Text Publishing’s edition advertises Big Meg as: “The Story of the Largest and Most Mysterious Predator that Ever Lived”. While these words are intended to excite readers, scientists have not yet assigned a definitive shape or weight to the megalodon. How sure can we be that it was the largest predator? <a href="https://en.wikipedia.org/wiki/Livyatan">Livyatan</a>, for instance, a prehistoric sperm whale, was an estimated 17.5m long and sported the largest teeth of any known creature. </p>
<p>At any rate, Tim and Emma Flannery approach the mysterious megalodon with imagination and intelligent speculation. They draw on what is already known of other species of sharks, while accepting this one could have been quite different.</p>
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Read more:
<a href="https://theconversation.com/ancient-megalodon-super-predators-could-swallow-a-great-white-shark-whole-new-model-reveals-188749">Ancient megalodon super-predators could swallow a great white shark whole, new model reveals</a>
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<p>The book begins with an account of Tim as a teenage fossil-hunter in western Victoria. After unprecedented floods in 1973 expose a fresh layer of fossils for exploration, he finds a large megalodon tooth. From this moment, his passion is fired to find out more about this mysterious creature.</p>
<p>At the Museum of Victoria, Tim finds a curator who becomes his lifelong mentor. Tim had already found bits of a fossilised seal at Melbourne’s Beaumaris beach, so his mentor employs him to look for the rest of it on the understanding he must hand over anything he finds. On his first day’s dive, Tim discovers a beautiful, large, green megalodon tooth. He agonises over parting with it.</p>
<p>More than four decades later, he finds closure when he revisits this tooth at the museum. (Ironically, his mentor tells him: “I would have been happy for you to keep it.”) As he once more holds the tooth in his hand, reflecting on its rightful place in the museum’s collection, he realises he “had finally grown up”.</p>
<p>Throughout the book, Tim and Emma explore this tooth’s place in Earth’s emerging environments with an ease that comes with extensive knowledge of the subject. Drawing on comparative examples of fossilised prey, they imaginatively recreate the megalodon’s life in the ancient oceans as an apex predator. </p>
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<span class="caption">Tim and Emma Flannery.</span>
<span class="attribution"><span class="source">Photo: Kate Holden</span></span>
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<p>Exactly when the megalodon became extinct remains a mystery, but several reasons are offered as to why it did – including, perhaps, that the food required to sustain such enormous creatures was running low during the <a href="https://en.wikipedia.org/wiki/Pliocene">Pliocene</a> epoch (5.33 million to 2.58 million years ago). With fierce competition from sharks such as great whites, the supposedly bigger female megalodons, in particular, may have been just too large for the oceans to sustain the needs of any more than a small population. The species, write the authors, “may have always lived on a knife edge”.</p>
<p>As we follow this toothy tale, we learn of the cult of collectors, some of whom will go to extraordinary lengths, diving to dangerous, pitch-dark depths, to acquire a much-prized tooth. </p>
<p>Megalodon teeth vary considerably in appearance because of the absorption of particular chemicals in rocks and sediment in the many locations where they have been found. The authors describe the beauty of some of the teeth they have seen – jewel-like, variously coloured and patterned – pointing readers towards some of the likeliest sites for successful fossil-hunting. The US east coast (especially North Carolina) is a particularly rich hunting ground.</p>
<p>However, they point out that hunting is not without its dangers. Amateur fossil excavation can also risk disturbing valuable sites.</p>
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Read more:
<a href="https://theconversation.com/meg-2-the-truth-about-the-extinct-mega-shark-and-why-even-this-ridiculous-film-could-inspire-future-palaeontologists-210751">Meg 2: the truth about the extinct mega shark – and why even this ridiculous film could inspire future palaeontologists</a>
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<h2>Truth in a tooth</h2>
<p>In the absence of a fully fossilised megalodon discovery that might reveal its shape and likely weight, it seems there is still a lot of truth in a tooth. The largest megalodon tooth yet found is “18cm from base to tip” and “almost certainly came from an individual that exceeded 15m in length”.</p>
<p>The shape of the tooth and its serrations confirm its job was to kill other marine mammals. The tooth’s marks on ancient bones or positions within them can reveal what the megalodon ate, while its colour, pattern and lustre can reveal the location of the creature when it died. </p>
<p>The authors acknowledge that the megalodon is not the ancestor of the great white shark – but analogies are made with this shark to allow the reader to get some sense of the kind of creature the megalodon might have been.</p>
<p>Two chapters, “Shark Eats Man” and “Man Eats Shark”, are almost entirely taken up with accounts of great white sharks, tiger sharks or bull sharks, either attacking humans, being attacked, or otherwise being used by humans to feed their desire for shark deities, shark trophies or shark fin soup. All of this rather distracts from the otherwise entertaining and informative story.</p>
<p>There is real passion in this story, but also horror and terror. Given the frequent analogies made with much oppressed, present-day sharks, more moderate language might have been used. The poor <a href="https://en.wikipedia.org/wiki/Greenland_shark">Greenland sharks</a> are gruesomely described. The great whites and others become the stuff of nightmares. Readers who will never experience the beauty of these elegant and inquisitive creatures in their own environments may well associate these sharks with the imagined meg, a “terrifying”, “horrifying” “monster”, with “razor-sharp teeth” that is the star of this book.</p>
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<span class="caption">Man Eating Shark. Two chapters of the book focus on human-shark interactions.</span>
<span class="attribution"><span class="source">Sculpture and Photo: Dave Williams</span></span>
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Read more:
<a href="https://theconversation.com/friday-essay-the-meg-is-a-horror-story-but-our-treatment-of-sharks-is-scarier-100886">Friday essay: The Meg is a horror story but our treatment of sharks is scarier</a>
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<p>In a final chapter, the authors return to the megalodon. Cryptozoologists, who search the planet for signs that creatures believed to be extinct are still alive, are on the trail of the megalodon following <a href="https://www.australiangeographic.com.au/topics/wildlife/2017/08/everything-you-need-to-know-about-the-megamouth-shark/">the discovery by a US navy ship in 1976 of a supposedly extinct megamouth shark</a>, a contemporary of the megalodon.</p>
<p>Tim and Emma doubt megalodons are still out there. The sharks would hunt, they reason, where they would be seen by us and there have been no traces of even parts of a megalodon washed ashore, as in the case of other large and mysterious creatures.</p>
<p>However, they’re optimistic that further scientific discoveries will reveal more about the true shape and size of the creature. </p>
<p>If a complete set of teeth could be found – exactly as they lay in the mouth – this would reveal how the jaws worked, how many teeth there were, and what megalodons primarily hunted. If enough of a fossil was found to indicate the length and shape of the fins, we might learn more about the megalodon’s swimming and hunting strategies.</p>
<p>In 1988, the fossil of an extinct cartilaginous shark (<em>Carcharodon hubbelli</em>) was <a href="https://www.foxnews.com/science/whos-your-daddy-great-white-sharks-parent-found">unearthed by an olive farmer</a> in the <a href="https://en.wikipedia.org/wiki/Pisco_Formation">Pisco Formation of Southern Peru</a>.</p>
<p>Tim Flannery suggests that if a megalodon fossil were to be found, it would most likely be in the Pisco Formation “where the ancient sea floor, miraculously preserved, is laid out in exquisite detail”.</p>
<p>For now, the creature, whose arrowhead tooth once sat in his youthful hand – pointing him to the path of palaeontology – exists largely in his imagination: the “megalodon in all its terrifying glory”.</p><img src="https://counter.theconversation.com/content/211506/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vivienne Westbrook has been the recipient of many international research funding institutes, though is not presently being funded by any organisation.</span></em></p>Megalodons are having a cultural moment. What do we know about them? And might further scientific discoveries reveal more about the true shape and size of these creatures?Vivienne Westbrook, Adjunct Senior Research Fellow, Oceans Institute, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2107512023-08-01T14:44:03Z2023-08-01T14:44:03ZMeg 2: the truth about the extinct mega shark – and why even this ridiculous film could inspire future palaeontologists<p><em>Otodus megalodon</em>, the biggest shark of all time, has long captured the imaginations of palaeontologists and the public alike. Scientific fascination spawns from the sheer enormity of their fossilised teeth. As big as human hands and serrated like kitchen knives, they were used for cutting down whales unlucky enough to encounter these sharks. </p>
<p>This gigantic predator has been further propelled into the limelight through popular culture. Nowhere has the megalodon made a bigger splash than its starring role in 2018’s The Meg, which will be followed by a sequel this year, Meg 2: The Trench. </p>
<p>Adapted from the bestselling novel <a href="https://www.stevealten.com/books/the-meg/">Meg: A Novel of Deep Terror</a> by Steve Alten, The Meg tells the story of a group of scientists discovering megalodon living in the Mariana Trench in the western Pacific Ocean.</p>
<p>The film is undeniably riddled with scientific inaccuracies. However, I can’t help but appreciate The Meg. A ridiculous film? Yes. But everyone involved seems very aware of this, making for highly entertaining viewing. </p>
<p>In my professional opinion, if a future palaeontologist becomes inspired and makes new megalodon discoveries because they saw this unserious film, then its existence has surely been a good thing.</p>
<p>I feel this way because it is ultimately my own story. </p>
<p>The very reason I discovered megalodon was because I watched a media depiction of it – specifically the BBC documentary series <a href="https://www.bbc.co.uk/programmes/p008c6n4">Sea Monsters</a> (2003) in which zoologist Nigel Marven visits prehistoric seas in his time-travelling boat to dive with ancient beasts. </p>
<p>I was just six at the time. I am now, 20 years later, a practising palaeobiologist specialising in fossil sharks and my most <a href="https://www.nature.com/articles/s41598-020-71387-y">well-known</a> <a href="https://www.science.org/doi/full/10.1126/sciadv.abm9424">work</a> revolves around none other than megalodon. </p>
<h2>Megalodon biology and cinematic representation</h2>
<p>The Meg does take artistic licence with available scientific knowledge. For example, the sharks are portrayed at exaggerated sizes of 27 metres (88 feet). The <a href="https://doi.org/10.26879/1140">most recent scientific extrapolations from tooth size</a>, however, estimate a maximum size of 20 metres (65 feet) long, still making it one of the largest predators that have ever existed.</p>
<p>Some dismiss megalodon’s appeal as beginning and ending with its humongous size. Nothing could be further from the truth.</p>
<p>For starters, this shark was everywhere. Its fossil teeth occur in geological formations on <a href="https://doi.org/10.1111/jbi.12754">six continents dating across 20 million years</a> during the Miocene and Pliocene epochs (23 million years ago to around 3 million years ago).</p>
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<p>Intriguingly, some of those formations were shallow habitats with lots of small megalodon teeth: telltale signs of nurseries where the babies were left to grow with plenty of food and protection from predators. One such site is <a href="https://doi.org/10.1371/journal.pone.0010552">Panama’s Gatun Formation</a>, which is referenced in The Meg.</p>
<p>Unravelling megalodon’s predatory ecology from fossils is even more interesting. </p>
<p>Its enormous teeth have left behind nasty injuries on whales that fell victim to its <a href="https://doi.org/10.1111/j.1469-7998.2008.00494.x">massive bite force</a>, including <a href="https://doi.org/10.26879/1171">baleen whales</a> and even <a href="https://doi.org/10.4202/app.00820.2020">sperm whales</a>. Using 3D modelling around <a href="https://www.science.org/doi/full/10.1126/sciadv.abm9424">a 140-vertebrae spinal column</a>, researchers have made stomach volume calculations that suggest megalodon could eat predators the size of today’s killer whales <a href="https://www.science.org/doi/full/10.1126/sciadv.abm9424">in just a few bites</a>. </p>
<p>Recent chemical analyses from teeth have also produced compelling findings. Nitrogen isotope values from megalodon are <a href="https://www.science.org/doi/10.1126/sciadv.abl6529">exceptionally high</a>, indicating it was higher up the food chain than any living marine predator. In short, the megalodon was the most apex of ocean predators.</p>
<p><a href="https://doi.org/10.1371/journal.pone.0185185">Oxygen isotopes</a> in fossils demonstrate <a href="https://www.pnas.org/doi/full/10.1073/pnas.2218153120">higher body temperatures than the surrounding environment</a>. This indicates mesothermy – an ability to maintain high body temperatures seen in only a few species such as <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1500316112">great whites, mako sharks</a> and <a href="https://doi.org/10.3354/esr01257">basking sharks</a>. </p>
<p>Mesothermy <a href="https://doi.org/10.1111/1365-2435.13869">enhances swimming speeds</a>, allowing a megalodon to travel faster and further, increasing its chances of finding prey. This active lifestyle would have forced megalodon to eat more food – around <a href="https://www.science.org/doi/full/10.1126/sciadv.abm9424">98,000 kcal every day</a> – to justify its size. As such, <a href="https://doi.org/10.1038/s41559-017-0223-6">the loss of its coastal habitats and associated prey</a> would have limited food intake and possibly starved it into extinction 3 million years ago.</p>
<p>The upcoming Meg 2 will feature a slightly different ecology. It is due to depict a megalodon devouring a <em>Tyrannosaurus rex</em>. The shark first evolved more than 40 million years after non-avian dinosaurs went extinct so, unfortunately, this clash of the iconic beasts would never have happened in reality. It is, however, a nod to Steve Alten’s original novel that also featured such a fantastical scene. And it should make for a very cool moment of cinematic absurdity.</p>
<h2>A better story for sharks</h2>
<p>Notably, The Meg portrays megalodon as surviving into the present day. This is impossible because the fossil record shows the disappearance of the <a href="https://www.science.org/doi/full/10.1126/sciadv.abm9424">apex super-predator</a> megalodon had a cascading effect on the ecosystem. It caused <a href="https://doi.org/10.7717/peerj.6088">the spread of great white sharks</a>, for example, and allowed whales to get even bigger because there were <a href="https://doi.org/10.1371/journal.pone.0111086">no more giant sharks to fear</a>.</p>
<p>Unfortunately, media depictions like this can drive bizarre <a href="https://www.livescience.com/animals/extinct-species/could-the-megalodon-still-exist-today">conspiracy theories</a> that megalodons are somehow still alive. This is, of course, nonsense but isn’t necessarily the fault of The Meg. <a href="https://entertainment.time.com/2013/08/07/discovery-channel-provokes-outrage-with-fake-shark-week-documentary/">Fake documentaries</a> using actors as scientists are far more guilty than a silly Hollywood movie.</p>
<p>Would I like to see films that accurately use all available science to depict such a remarkable shark? Of course. But entertainment is what it is. </p>
<p>Sharks continue to be <a href="https://www.theguardian.com/commentisfree/2023/jul/28/jaws-shark-attack-panic-oceans-warm">portrayed negatively in the wider media</a>, despite <a href="https://doi.org/10.1016/j.cub.2021.08.062">up to a third of today’s sharks being threatened with extinction</a>.</p>
<p>So if Hollywood is going to continue portraying living megalodons, then I feel the most interesting aspect of this fictional scenario has yet to be properly explored: would we be far more dangerous to megalodons than they would be to us? I think the answer is a resounding “yes”. </p>
<p>We kill as many as <a href="https://doi.org/10.1016/j.marpol.2012.12.034">100 million sharks every year</a> and <a href="https://doi.org/10.1111/j.1461-0248.2010.01489.x">the largest ones are at particular risk</a>. This could be a powerful story to help explain the importance and vulnerability of today’s sharks to modern audiences, the same way The Meg brings attention to the biggest shark of all. </p>
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<p class="fine-print"><em><span>Jack Cooper is a PhD researcher at Swansea University, specialising in the palaeoecology of fossil sharks. He receives funding via a studentship from the Fisheries Society of the British Isles. </span></em></p>A paleobiologist on why he appreciates the franchise despite its inaccuracies.Jack Cooper, Doctoral researcher in Palaeobiology, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2093332023-07-30T20:08:25Z2023-07-30T20:08:25ZThe 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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<strong>
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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</p>
<hr>
<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>
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</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>
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<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 AustraliaJessica Meeuwig, Wen Family Chair in Conservation, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2098652023-07-28T03:33:58Z2023-07-28T03:33:58ZYou’ve heard the annoyingly catchy song – but did you know these incredible facts about baby sharks?<p><em>“Baby shark doo-doo doo-doo doo-doo, baby shark doo-doo doo-doo doo-doo …”</em> If you’re the parent of a young child, you’re probably painfully familiar with this infectious song, which now has <a href="https://www.youtube.com/watch?v=XqZsoesa55w">more than 13 billion views</a> on YouTube.</p>
<p>The Baby Shark song, released in 2016, has got hordes of us singing along, but how much do you really know about baby sharks? Do you know how a baby shark is born, or how it survives to become an apex predator? </p>
<p>I study coastal marine ecology. I believe baby sharks are truly fascinating, and I hope greater public knowledge about these creatures will help protect them in the wild. </p>
<p>So sink your teeth into this Q&A on the weird and wonderful world of baby sharks.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/XqZsoesa55w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>How are baby sharks conceived and born?</h2>
<p>To the human eye, shark courtship practices may seem barbaric. Males typically attract the attention of a female by biting her. If successful, this is generally followed by even toothier bites to hold on <a href="https://www.bing.com/videos/search?q=mating+of+sharks+youtube+video+sharktrust&&view=detail&mid=F06D036ECEF53DA14F94F06D036ECEF53DA14F94&&FORM=VRDGAR&ru=%2Fvideos%2Fsearch%3Fq%3Dmating%2Bof%2Bsharks%2Byoutube%2Bvideo%2Bsharktrust%26FORM%3DHDRSC6">during copulation</a>. Females can carry the scars of these encounters long after the mating season is over. </p>
<p>The act of copulation itself is comparable to that of humans. The male inserts its sexual organ, known as a “clasper”, into the female and releases sperm to <a href="https://ocean.si.edu/ocean-life/sharks-rays/sharks">fertilise the eggs</a>. </p>
<p>However, in extremely rare cases, sharks can reproduce asexually – in other words, embryos develop without being fertilised. This occurred at a Queensland aquarium in 2016, when a zebra shark <a href="https://www.sciencealert.com/zebra-shark-makes-world-first-switch-from-sexual-to-asexual-reproduction">gave birth</a> to a litter of pups despite not having had the chance to mate in several years.</p>
<p>Sharks give birth in a variety of ways. Some species produce <a href="https://www.sharktrust.org/shark-reproduction">live pups</a>, which swim away to fend for themselves as soon as they’re born. Others hatch from eggs outside the mother’s body. Remnants of these egg cases have been found washed up on beaches across the world.</p>
<h2>How big is a litter of shark pups?</h2>
<p>Litter size across sharks varies considerably. For example, the grey nurse shark starts with several embryos but only two are born. This is because the embryos actually eat each other while in utero! This leaves only one survivor in each of the mother’s two uteruses.</p>
<p><a href="https://www.australiangeographic.com.au/fact-file/grey-nurse-shark/">Intrauterine cannibalism</a> may seem disturbing but is nature’s way of ensuring that the strongest pups get the best chance of survival. </p>
<p>In contrast, other species such as the <a href="https://www.fisheries.noaa.gov/feature-story/eight-surprising-shark-facts">whale shark</a> use a completely different strategy to ensure some of their offspring survive: having hundreds of pups in a single litter. </p>
<h2>Where do baby sharks live?</h2>
<p>The open ocean is a dangerous place. That’s why pregnant female sharks often give birth in shallow coastal waters known as “nurseries”. There, baby sharks are better protected from harsh environmental conditions and roaming predators, including other sharks.</p>
<p>Sites for shark nurseries include river mouths, estuaries, mangrove forests and coral reef flats. </p>
<p>For example, the white shark has established nursery grounds along the <a href="https://www.australiangeographic.com.au/topics/wildlife/2011/12/great-white-shark-nursery">east coast</a> of Australia, where babies may remain for several years before moving to deeper waters.</p>
<p>Although most types of sharks are confined to saltwater, the bull shark <a href="https://australian.museum/learn/animals/fishes/bull-shark-carcharhinus-leucas-valenciennes-1839/#:%7E:text=The%20Bull%20Shark%20can%20live,for%20extended%20periods%20in%20freshwater.">can live</a> in freshwater habitats. Bull shark pups born near river mouths and estuaries often <a href="https://www.abc.net.au/news/2017-11-29/curious-north-coast-sharks/9197516">migrate upstream</a> (sometimes vast distances inland) to escape being preyed upon.</p>
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<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>
<figure class="align-center ">
<img alt="young sharks swim in shallow water" src="https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539886/original/file-20230728-19-j6pxbd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Baby sharks are often born in ‘nurseries’ - shallow coastal waters where food is plentiful and ocean predators are less likely.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>When are baby sharks born?</h2>
<p>Sharks, like most animals in the wild, generally give birth during periods that provide favourable conditions for their offspring. </p>
<p>In Australia, for example, <a href="https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0014/433121/Primefact-1218-Scalloped-Hammerhead-Shark-Sphyrna-lewini.pdf#:%7E:text=Scalloped%20Hammerheads%20give%20birth%20to%20live%20young.%20This,litters%20of%2013%20-%2041%20pups%20%28averaging%2025%29">scalloped hammerheads</a> and <a href="https://www.abc.net.au/news/2022-02-05/sharks-la-nina-breeding-rainfall-influx/100805590">bull sharks</a> tend to breed in the wet summer months when nursery grounds are warmer and there are rich feeding opportunities.</p>
<h2>How long do baby sharks take to grow up?</h2>
<p>Sharks grow <a href="https://saveourseas.com/worldofsharks/threats/slow-reproduction">remarkably slowly</a> compared to other fish and remain juveniles for a long time. Although some species mature in a <a href="https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0206581">few years</a>, most take considerably longer.</p>
<p>Take the Greenland shark – the world’s longest living shark. It can live to <a href="https://oceanservice.noaa.gov/facts/greenland-shark.html">at least 250 years</a> and according to <a href="https://www.nationalgeographic.com/animals/article/greenland-sharks-animals-science-age">recent research</a>, it’s thought to take more than a century to reach <a href="https://oceanservice.noaa.gov/facts/greenland-shark.html">sexual maturity</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/surfers-share-their-waves-with-sharks-but-fear-not-193395">Surfers share their waves with sharks, but fear not</a>
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</em>
</p>
<hr>
<h2>What threats do baby sharks face?</h2>
<p>While small, sharks must eat or be eaten – all the while enduring the elements and finding enough food to survive and grow. </p>
<p>Yet there is another challenge: humans. In fact, we are the <a href="https://australian.museum/learn/animals/fishes/shark-myths-and-facts/">greatest threat</a> to sharks.</p>
<p>Shark nurseries are heavily concentrated in coastal zones, and often overlap with human activities such as fishing, boating and coastal development. And because sharks grow <a href="https://saveourseas.com/worldofsharks/threats/slow-reproduction">so slowly</a>, they are particularly to vulnerable to <a href="https://www.sharktrust.org/shark-threats">overfishing</a> because when populations decline, they can take a long time to bounce back. </p>
<h2>Much more to learn</h2>
<p>Scientists are still working to understand the life cycles of the <a href="https://ocean.si.edu/ocean-life/sharks-rays/sharks#:%7E:text=500%2B%20Species,-Sharks%20come%20in&text=With%20over%20500%20species%20of,39%20feet%20(12%20meters).">500-plus species of sharks</a> in our oceans. Each time I hear the song Baby Shark, it reminds me there’s a lot more work to do. </p>
<p>It’s crucial to keep monitoring and studying these baby wonders of the deep, to ensure shark populations survive and we maintain the delicate balance of our underwater ecosystems.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-we-swim-in-the-ocean-we-enter-another-animals-home-heres-how-to-keep-us-all-safe-193457">When we swim in the ocean, we enter another animal's home. Here's how to keep us all safe</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/209865/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaelen Nicole Myers receives funding from James Cook University, the Ecological Society of Australia, and the Royal Zoological Society of New South Wales.</span></em></p>Some baby sharks eat their unborn siblings in utero, while others spend 100 years in childhood. Sink your teeth into the weird world of these juvenile wonders of the deep.Jaelen Nicole Myers, PhD Candidate, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2062852023-07-13T20:56:33Z2023-07-13T20:56:33ZReversing the decline in shark and ray populations is possible, but requires strong governance and management<figure><img src="https://images.theconversation.com/files/531993/original/file-20230614-17-l5ljpl.jpg?ixlib=rb-1.1.0&rect=190%2C539%2C1358%2C815&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sharks and rays are rapidly declining globally, and their situation is representative of many other exploited marine species that lack scientific monitoring.</span> <span class="attribution"><span class="source">(Carlos Diaz/Ocean Image Bank)</span></span></figcaption></figure><p>The oceans remain vast and inscrutable. While technology has revolutionized our capacity to track threats to biodiversity on land, our understanding of the status of marine biodiversity remains <a href="https://doi.org/10.1126/science.abj0211">fragmented and biased toward economically high-valued species</a>. </p>
<p><a href="https://doi.org/10.1111/faf.12593">Most fish species are not scientifically monitored</a>, which is done by collecting and analyzing population data. Global marine fish catches continue to be underestimated, with as much as <a href="https://doi.org/10.1038/ncomms10244">one-third missing</a>.</p>
<p>The fast decline of shark and ray species globally is representative of many other exploited marine species that lack scientific monitoring and <a href="https://doi.org/10.1016/j.ocecoaman.2019.104994">a general political will for fisheries management</a>. </p>
<p><a href="https://doi.org/10.1038/s41586-020-03173-9">Seventy-one per cent of oceanic shark and ray populations have been depleted in the last half-century</a> and <a href="https://doi.org/10.1016/j.cub.2021.08.062">one-third of all 1,199 shark and ray species are now threatened with extinction</a>, based on the International Union for Conservation of Nature (IUCN) criteria, primarily due to overfishing. These species have a key role in marine ecosystem functioning and human food security.</p>
<p>Fortunately, there are signs of hope. New scientific techniques and recent efforts of the scientific community have helped create a more comprehensive picture of the speed and scale of these changes, highlighting successful cases of protection and management efforts, including those in <a href="https://doi.org/10.1016/j.cub.2016.12.017">Australia, New Zealand, the United States, Canada and the European Union</a>.</p>
<h2>Coastal sharks and rays missing in some areas, thrive in others</h2>
<p>In 2019, our team of experts carried out IUCN Red List assessments in the Bahamas to determine the global extinction risk status of several sharks and rays.</p>
<p>We found ourselves attempting to reconcile widely divergent views of the regional status of species that were more common in the northwest Atlantic and rare or near absent in the southwest Atlantic.</p>
<p>To understand the reasons for this difference, we gathered data on population status of all 26 coastal sharks and rays — ranging from north to south — across the western Atlantic Ocean, examining the factors like fishing pressure and management effort that could influence the extinction risk status of these species.</p>
<p>We found that <a href="https://doi.org/10.1073/pnas.2216891120">populations of the same species had collapsed in the southwest Atlantic due to unrestrained fishing</a>. Across the whole region, we saw that although fishing pressure increased extinction risk, the strength of management engagement was widely overlooked, despite it reducing the extinction risk of all 26 wide-ranging sharks and rays. </p>
<p>The bonnethead shark species (<em>Sphyrna tiburo</em>) is an excellent <a href="https://www.iucnredlist.org/species/39387/205765567#population">example</a> of what is happening in the Western Atlantic region. The species is abundantly found in the northern part of its range. But further south, it hasn’t been seen in decades.</p>
<figure class="align-center ">
<img alt="A bonnethead shark swims in green waters" src="https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=365&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=365&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=365&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=459&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=459&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=459&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Abundantly found in the northern Atlantic waters, bonnethead sharks are no longer seen in the south.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>So, why is this happening?</p>
<p>In the United States, this shark species is managed by catch quota, while in Mexico there is a seasonal fishery quota. The Bahamas has been dubbed a ‘<a href="https://oceanographicmagazine.com/features/true-value-shark-sanctuaries/">shark sanctuary</a>’ because of their ban on commercial shark fishing.</p>
<p>Further south, there is no discernible management and this species is captured in unregulated targeted fisheries and as retained incidental catch. Down south, this species is likely subject to heavy unmanaged fishing pressure in most countries. It is very rarely found in Colombia and has collapsed in Brazil where there are very few recent records.</p>
<h2>A road map for shark recovery</h2>
<p>The <a href="https://www.fisheries.noaa.gov/sustainable-fisheries/atlantic-shark-fisheries-management-highlights-timeline#1993">U.S. Fishery Management Plan for Sharks of the Atlantic Ocean</a> was implemented by the National Oceanic and Atmospheric Administration in 1993.</p>
<p>This plan was developed in response to the <a href="https://www.fisheries.noaa.gov/sustainable-fisheries/atlantic-shark-fisheries-management-highlights-timeline#1976">intense expansion of commercial and recreational fisheries in the 1970s to 1980s due to the increased global demand for shark meat, fins and cartilage as well as the concerns about their effects on shark populations</a>.</p>
<p>We found that populations in the northwest Atlantic recovered shortly after the implementation of this management plan.</p>
<figure class="align-right ">
<img alt="A pile of fish." src="https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.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">
<figcaption>
<span class="caption">Requiring sharks to be brought ashore with fins attached as per the Shark Conservation Act of 2010 vastly improved species identification and the quality of data, providing a better means for enforcing regulations.</span>
<span class="attribution"><span class="source">(NOAA Fisheries)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Thirty years after this implementation, we found the stabilization of three populations. We also documented the rebuilding population of six of the 11 coastal sharks here. </p>
<p>We believe that this success can be attributed to:</p>
<ul>
<li><p>A strong regulation system where catch is prohibited for some species (or group of species) and limited for others. A system that improves catch reporting and reduces the pressure of fishing through the reduction of the number of shark-directed fishing permits.</p></li>
<li><p>strict enforcement by the U.S. Coast Guard and law enforcement agencies for fishers in U.S. waters</p></li>
<li><p>continuous monitoring of the fishery for data collection</p></li>
</ul>
<h2>Recovering species population through collaboration</h2>
<p>Our research found that halting and reversing declines and creating sustainable fisheries is possible even for wide-ranging sharks and rays.</p>
<p>But this requires strong governance and management.</p>
<p>Concerted efforts can bridge the spots of successful management and recovery with adjacent nations where the species are still in decline, leading to success at a global scale. This approach will ensure that successful conservation in one country is not undone by less regulated fishing areas outside those borders.</p>
<p>Developed nations, that are bringing their fisheries into sustainability and importing more fish, should translate their successes into capacity-building lessons to support other nations undergoing the transition towards sustainability.</p><img src="https://counter.theconversation.com/content/206285/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was funded by the Shark Conservation Fund as part of the Global Shark Trends Project</span></em></p>Through regulation, enforcement and monitoring, fisheries management can lead to recoveries in shark and ray populations.Nathan Pacoureau, Postdoctoral Research Fellow, Global Shark Trends Project, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2082692023-07-11T12:29:02Z2023-07-11T12:29:02ZSawfish, 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 UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1981372023-02-21T19:41:35Z2023-02-21T19:41:35Z104 shark and ray species now receive new protections, but are they enough?<figure><img src="https://images.theconversation.com/files/508750/original/file-20230207-27-oyd3os.jpg?ixlib=rb-1.1.0&rect=58%2C400%2C5501%2C3300&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Shark and stingray populations have declined by 71 per cent in the last half-century</span> <span class="attribution"><span class="source">(Hannes Klostermann / Ocean Image Bank)</span></span></figcaption></figure><p><a href="https://doi.org/10.1016/j.cub.2021.08.062">Shark populations have been declining for years</a>, largely due to overfishing. And for years, the solutions offered by researchers have included increasing the number, <a href="https://doi.org/10.1038/nature13022">size and effectiveness of marine protected areas (MPA)</a> and <a href="https://doi.org/10.1111/faf.12695">improving the global management of sharks and stingrays in fisheries that catch them</a>.</p>
<p>However, the large expanse of the ocean makes it hard to properly enforce protections in these MPAs, making this a global challenge. A solution to this issue lies in the use of international treaties like the <a href="https://cites.org/eng">Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)</a>, wherein 184 member countries propose ways to ensure that species are not threatened due to international trade.</p>
<p>At the recent <a href="https://cites.org/eng/cop19">CITES Conference of the Parties (COP19) held in Panama City</a> in November 2022, I witnessed the discussions that went into four proposals to include 104 shark and ray species in the CITES Appendix II. The acceptance of these four proposals, which included 54 requiem sharks, 37 guitarfishes, six hammerheads and seven river rays, would restrict their trade to sustainable and legal avenues. </p>
<p>This listing would impact global fisheries and trade, especially considering that the requiem sharks make up over <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12940">half of the global annual reported catch of sharks and rays</a>. Guitarfishes are, meanwhile, <a href="https://doi.org/10.1038/s41467-022-35091-x">heavily traded throughout Africa and southern Asia</a>. <a href="https://www.traffic.org/news/cites-cop19-summary/">All four shark and ray proposals passed and the species were added to the list</a>. But how good is this news really?</p>
<h2>Why are sharks and rays declining today?</h2>
<p>On the surface, these new protections for sharks and rays are a step in the right direction. But, being listed on CITES means the species’ population was in steep decline, driven by humans trading these species at unsustainable levels. </p>
<p>This unsustainable trade is due to <a href="https://doi.org/10.1016/j.gecco.2015.05.003">improper management</a>, or in some cases — no management of the catch and landing of sharks and rays in fisheries.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&rect=8%2C125%2C5576%2C3600&q=45&auto=format&w=1000&fit=clip"><img alt="Whitetip reef shark swimming" src="https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&rect=8%2C125%2C5576%2C3600&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508749/original/file-20230207-13-271v48.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">In fisheries across 30 nations and four Regional Fisheries Management Organizations, only half the ideal management efforts are in place for requiem sharks including this whitetip reef shark.</span>
<span class="attribution"><span class="source">(Brook Peterson/ Ocean Image Bank)</span></span>
</figcaption>
</figure>
<p>In our newly published paper, we revealed that <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12940">requiem sharks only have half of the ideal management</a> in place and in another paper show that <a href="https://cites.org/sites/default/files/documents/E-CoP19-Inf-78.pdf">guitarfish have just 45 per cent of ideal management</a> in fisheries across 30 countries and four Regional Fisheries Management Organizations.</p>
<p>On assessing their <a href="https://doi.org/10.1111/faf.12695">fisheries management</a>, we found that most countries have a central management body in place, engage with international treaties (like CITES) and manage illegal, unreported and unregulated fishing. This shows they have the capacity and infrastructure to ideally manage sharks and rays.</p>
<p>However, this was not usually the case. We found most countries have little understanding of the population status of species in their waters and few, if any, landing limits — number of individuals or total tonnes allowed to be caught — were imposed for sharks and rays. </p>
<p>We did find that landing limits were more likely to exist for species already listed on CITES Appendix II — like the <a href="https://cites.org/sites/default/files/shark-ndf/Marine%20Fisheries%20Policy%20Series_NDF%20Silky%20Shark.pdf">Oceanic Whitetip and Silky Sharks</a>. Therefore, the inclusion of an additional 104 species will hopefully improve management of sharks and rays in fisheries globally. </p>
<p>There are big differences in how well sharks and rays are managed globally. In wide-ranging species, like many requiem sharks, they are subject to a patchwork of management. For example, <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12940">the Blacktip Reef Shark is well-managed in Australia, but less so elsewhere in its range</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1593619728232161280"}"></div></p>
<p>While guitarfish are found throughout the tropics, the distribution of their various individual species vary across waters of different countries. One species is found in Tanzania and Madagascar, while another can be found in Malaysia and Indonesia. Another species is found in the waters surrounding Taiwan. This varied distribution means that each species’ global status is directly related to how well these countries manage their catch. </p>
<p>According to the <a href="https://www.iucnredlist.org/">International Union for Conservation of Nature’s Red List of Threatened Species</a>, over 77 per cent of guitarfish are threatened with extinction, meaning current management is not working. What’s worse? <a href="https://www.biorxiv.org/content/10.1101/2022.10.05.510982v1">There is no data regarding the volume and species of guitarfish that are traded internationally</a>. </p>
<p>We need fisheries legislation that requires species-specific reporting of catch and trade in these species to better understand the population status and changes in abundance of these species. </p>
<h2>How does Canada fit in?</h2>
<p>Canada is blessed with vast forests, lakes and oceans. But it <a href="https://theconversation.com/cop15-biodiversity-summit-in-montreal-canada-failed-to-meet-its-2020-conservation-targets-will-2030-be-any-better-195347">failed to protect its biodiversity</a> as planned at the United Nations Convention on Biological Diversity (CBD) in Japan in 2010, or the <a href="https://www.cbd.int/sp/targets/">Aichi Biodiversity Targets</a>. </p>
<p>In particular, Target 11, which states 10 per cent of coastal and marine areas and 17 per cent of terrestrial and inland waters should be protected by 2020. Despite these targets not being met, more ambitious goals have been set at the most recent CBD meeting in Montréal, including <a href="https://www.carbonbrief.org/cop15-key-outcomes-agreed-at-the-un-biodiversity-conference-in-montreal/">protecting 30 per cent of the world’s land and ocean by 2030</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1165731811953172480"}"></div></p>
<p>Canada voted against protecting guitarfishes at CITES COP19. There are no guitarfishes that live in Canadian waters, nor is there any evidence of import. Therefore, this vote would not affect any catch, landings or trade for Canada.</p>
<p>All votes regarding requiem sharks were done by secret ballot, so Canada’s vote can only be speculated on. However, Canada spoke in support of the removal of ‘look-alike’ species, which includes the only requiem shark found in Canadian waters — <a href="https://www.iucnredlist.org/species/39381/2915850">the near-threatened Blue Shark</a>. </p>
<p>The discussions concluded with the final vote to include all requiem shark species on Appendix II, which was accepted with 75 per cent support including the European Union and its Member States and the USA who declared their votes publicly. </p>
<h2>What does this all mean?</h2>
<p>Canada should be transparent about the reasons environmental policies like the Aichi targets or the CITES voting are or are not put in place. Citizens have a right to know how their government is voting on international policies (like the protection of requiem sharks), and the reasons behind those decisions. </p>
<p>On a global scale, fisheries need to be managed as per the most susceptible species nations interact with. The excuse that sharks and rays are “<a href="https://www.foodsafetynews.com/2014/03/bycatch-blamed-for-nine-dirty-ocean-fisheries-off-u-s-shores/">unavoidable bycatch</a>” has led to severe declines in their populations in all environments. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/bYn6xImdGtU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Getting caught as unavoidable fisheries bycatch has steeply depleted shark populations today.</span></figcaption>
</figure>
<p>In the open ocean, shark and ray populations have <a href="https://doi.org/10.1038/s41586-020-03173-9">declined by 71 per cent</a> in the last half century. Sharks and rays have been so overfished on <a href="https://doi.org/10.1038/s41467-022-35091-x">coral reefs that almost two-thirds</a> are now threatened with extinction. </p>
<p>There is hope still.</p>
<p>New research shows that implementing <a href="https://doi.org/10.1073/pnas.2216891120">science-based effective limits on fishing can improve the status of shark populations</a>. However, it takes time for these long-lived animals to recover, which is why changes need to be made immediately. </p>
<p>Improved fisheries management is essential to ensure long-term sustainability for sharks and rays as well as the associated fisheries as food and income sources. Managing fisheries —<a href="https://doi.org/10.1016/j.cub.2021.08.062">the main threat for sharks and rays</a> — is the only way to prevent them from needing international protection like CITES in the future.</p><img src="https://counter.theconversation.com/content/198137/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Sherman received funding from the Shark Conservation Fund. She is a member of the IUCN SSC Shark Specialist Group</span></em></p>Over 100 shark and ray species were recently added to an international treaty, known as the CITES list, to protect them from the threat of unsustainable and illegal trade.Samantha Sherman, Postdoctoral research fellow in Biological Sciences, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1983502023-02-01T06:12:08Z2023-02-01T06:12:08ZSeychelles is becoming overwhelmed by marine plastic – we now know where it comes from<figure><img src="https://images.theconversation.com/files/507320/original/file-20230131-12-y5egtu.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C5087%2C3396&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A green turtle on Aldabra entangled in abandoned fishing gear.</span> <span class="attribution"><span class="source">Rich Baxter</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>More than 1,000km southwest of Mahé, the main inhabited island in Seychelles, lies a ring of coral islands called the <a href="https://en.wikipedia.org/wiki/Aldabra">Aldabra Atoll</a>. The islands are a <a href="https://whc.unesco.org/en/list/185/">Unesco world heritage site</a> and support a huge diversity of marine species including manta rays and tiger sharks. The atoll is also a <a href="https://theconversation.com/how-we-discovered-that-sea-turtles-in-seychelles-have-recovered-from-the-brink-179041">breeding site</a> for endangered <a href="https://www.worldwildlife.org/species/green-turtle">green turtles</a>.</p>
<p>Aldabra has long been <a href="http://www.sif.sc/aldabra">protected</a> from threats to its biodiversity by its remoteness. But now plastic debris is strewn across Aldabra’s coastlines, threatening nearby marine ecosystems. <a href="https://doi.org/10.1126/science.aar3320">Research</a> finds the likelihood of coral disease increases from 4% to 89% when coral are in contact with plastic.</p>
<p>The <a href="http://sif.sc/">Seychelles Islands Foundation</a>, who are responsible for managing Aldabra, conducted a plastic clean-up operation in partnership with <a href="https://www.ox.ac.uk/news/2020-09-10-millions-dollars-clean-tuna-nets-and-flip-flops-island-state">Oxford University</a> in 2019. Roughly 25 tonnes of plastic waste were removed from the islands. </p>
<p>A <a href="https://doi.org/10.1016/j.marpolbul.2022.114497">new study</a> that we co-authored modelled the flow of plastic debris in the Indian Ocean between 1993 and 2019 and traced it to its source. We found that none of the plastic that washes up on Aldabra comes from the islands themselves. </p>
<figure class="align-center ">
<img alt="An aerial shot of the Aldabra Atoll." src="https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=596&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=596&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=596&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=749&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=749&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507332/original/file-20230131-7253-8kr9t0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=749&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Aldabra Atoll, part of the Seychelles’ Outer Islands.</span>
<span class="attribution"><span class="source">Seychelles Islands Foundation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Simulating plastic flow</h2>
<p>Using data on plastic waste generation and fishing activity, we generated hundreds of billions of virtual plastic particles entering the Indian ocean. We then simulated their movement based on ocean currents, waves and winds.</p>
<p>Bottle caps and other low-buoyancy items sink fast and plastic loses buoyancy as it fragments or becomes <a href="https://www.sciencedirect.com/science/article/pii/S0269749116300264">covered in waterborne organisms</a>. Items that remain buoyant for longer are transported further distances. To reach Aldabra from the eastern Indian Ocean, our model estimates that debris must be floating for at least six months.</p>
<p>We determined the likelihood that this debris would wash up on the coast by analysing the rate at which <a href="https://www.aoml.noaa.gov/phod/gdp/index.php">scientific “drifters”</a> (instruments that record ocean currents) and <a href="https://www.sciencedirect.com/science/article/pii/S0006320720309976">GPS-tracked floating fishing devices</a> become “beached”. Free-floating instruments such as these behave well as proxies for floating plastic. These observations indicate that around 3% of the debris that is within 10km of a coast beaches each day.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ma0wlFfA6dI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Four-year simulation of highly buoyant marine debris transport in the Indian Ocean.</span></figcaption>
</figure>
<h2>Island under siege</h2>
<p>Our model predicts that Indonesia is responsible for most of the plastic debris, including as flip-flops and plastic packaging, that beaches across Seychelles. Various other countries including India, Sri Lanka and the Philippines are also major sources.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A figure showing the sources of marine debris across the Indian Ocean." src="https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=770&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=770&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=770&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=968&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=968&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506216/original/file-20230125-11-441nau.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=968&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sources of marine debris for Seychelles and other remote islands in the western Indian Ocean (1993-2014).</span>
<span class="attribution"><a class="source" href="https://creativecommons.org/licenses/by/4.0/">Vogt-Vincent et al. (2023)</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>But Seychelles is also contaminated with plastic waste from other places. </p>
<p>Almost half of the plastic bottles found on Aldabra during the initial clean-up had been manufactured in China. But ocean currents do not flow directly between China and the western Indian Ocean. It is thus unlikely that a large number of bottles could float from China to Seychelles. </p>
<p>But Seychelles is close to a <a href="https://www.marinetraffic.com/en/ais/home/centerx:63.4/centery:-8.7/zoom:4">major shipping lane</a> that connects southeast Asia to the Atlantic. If bottles were discarded from ships crossing the Indian Ocean then they would likely beach across Seychelles. </p>
<p><a href="https://doi.org/10.1038/s41598-020-71444-6">Research</a> that we conducted in 2020 estimated that the fishing industry was responsible for 83% of the plastic waste on Aldabra. Most of the fishing gear abandoned by <a href="https://www.msc.org/what-we-are-doing/our-approach/fishing-methods-and-gear-types/purse-seine">“purse seine” fisheries</a> (a method of fishing that employs large nets to catch tuna) likely relates to regional fishing activity around Seychelles. But abandoned gear from longline fisheries may have drifted in from as far afield as western Australia.</p>
<p>Perhaps most importantly, our modelling also suggests that the rates at which plastic debris will beach in the Indian Ocean will follow strong seasonal cycles. </p>
<p>Winds tend to have a <a href="https://iridl.ldeo.columbia.edu/maproom/Global/Climatologies/Vector_Winds.html?bbox=bb%3A15.12%3A-39.110%3A132.52%3A35.656%3Abb&T=Jul">southerly (northward) component</a> during the Indian Ocean’s summer monsoon season. But major debris sources such as Indonesia and India share similar, or more northerly, latitudes with Seychelles. During this period, debris from these sources tends to miss Seychelles and is transported further north. </p>
<p>By contrast, the winds reverse during the <a href="https://iridl.ldeo.columbia.edu/maproom/Global/Climatologies/Vector_Winds.html?bbox=bb%3A15.12%3A-39.110%3A132.52%3A35.656%3Abb&T=Jan">winter monsoons</a> and transport debris directly towards Seychelles. We expect plastic debris accumulation to peak in Seychelles shortly after the winter monsoons (February to April). In the southernmost islands, almost all of the debris that beaches will do so at this point. </p>
<figure class="align-center ">
<img alt="A map showing the direction of ocean currents in the Indian Ocean across different seasons." src="https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506218/original/file-20230125-12-c6pgwb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Schematic of ocean currents in the Indian Ocean.</span>
<span class="attribution"><a class="source" href="https://creativecommons.org/licenses/by/4.0/">Vogt-Vincent et al. (2023)</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Planning effective mitigation</h2>
<p>Seychelles is not responsible for generating this waste but face mounting environmental and economic costs. For example, <a href="https://doi.org/10.1038/s41598-020-71444-6">500 tonnes</a> of litter remained following the initial clean-up of Aldabra’s coasts, which may cost up to US$5 million (£4 million) to remove.</p>
<p>The United Nations last year <a href="https://www.unep.org/news-and-stories/story/what-you-need-know-about-plastic-pollution-resolution">agreed</a> to establish a <a href="https://www.plasticstreaty.org/">global plastic treaty</a> that will tackle plastic pollution at its roots. But negotiations only began recently and it may be a long time before the treaty has any meaningful impact. </p>
<figure class="align-center ">
<img alt="An aerial shot of a group of people removing litter from a beach." src="https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506404/original/file-20230125-22-6nbe1u.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">A team from the Seychelles Islands Foundation removing litter from the coastline of Aldabra.</span>
<span class="attribution"><span class="source">Seychelles islands Foundation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Until then our modelling may help to establish other strategies to reduce the accumulation of plastic debris in Seychelles. </p>
<p>We identified fishing gear and shipping as being responsible for the majority of plastic pollution on Seychelles. Better enforcement of existing laws such as the 1983 ban on the disposal of plastic into the sea under the <a href="https://www.imo.org/en/about/Conventions/Pages/International-Convention-for-the-Prevention-of-Pollution-from-Ships-(MARPOL).aspx">Marpol Convention</a> should reduce the amount of plastic entering the Indian Ocean.</p>
<p>Predicting the peak of plastic accumulation in Seychelles will also maximise the effectiveness of beach clean-ups. Removing litter shortly after its arrival will minimise the time debris spends being broken down into unmanageable fragments.</p>
<p>Remote Indian Ocean islands are increasingly affected by plastic waste generated overseas. But by modelling the flow of plastic debris, we now have the chance to develop more effective strategies to reduce plastic accumulation and strengthen demands for stronger commitments under the global plastic treaty. </p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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<p class="fine-print"><em><span>Noam Vogt-Vincent receives funding from the Natural Environment Research Council (NERC). </span></em></p><p class="fine-print"><em><span>April Burt works with Seychelles Islands Foundation, who manage Aldabra Atoll</span></em></p>Remote islands in the Indian Ocean are now strewn with plastic waste – the origin of this waste has until now not been established.Noam Vogt-Vincent, DPhil Candidate in Earth Sciences, University of OxfordApril Burt, Research Associate, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1919842023-01-31T20:02:10Z2023-01-31T20:02:10ZSharks and stingrays have been traded for centuries — here’s why that history could help save them<figure><img src="https://images.theconversation.com/files/506987/original/file-20230130-11-jtv92r.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3780%2C2733&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Freshly caught shark for sale at a market in Kerala, in southwest India.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p><a href="https://ocean.si.edu/ocean-life/sharks-rays">Sharks, along with rays</a>, and their products have been historically consumed and traded by many communities globally over centuries. Between 2012 and 2019, the trade in shark and ray meat was <a href="https://wwfeu.awsassets.panda.org/downloads/a4_shark_2021_low.pdf">valued at over US$4.1 billion</a>. </p>
<p>Sharks and rays each have complex and distinct chains of supply and distribution, which are harder to unravel, affecting the success of management initiatives. This is concerning for conservation efforts to be successful as sharks and rays are some of the most threatened species today, mostly due to overfishing. </p>
<p>In India, fresh, salted and dried shark meat were traditionally consumed in several coastal communities, especially along the country’s west coast. There, shark meat was a diet staple for the poor. Sharks are also consumed for cultural reasons, as their meat is considered a nourishing food for mothers after childbirth; while ray meat is consumed during festivities.</p>
<p>As a response to <a href="https://www.fao.org/3/x3690e/x3690e.pdf">the rising global demand for sharks between 1950 and 1980</a> for shark products such as shark liver oil and shark fin soup, targeted shark fisheries developed in several parts of India to meet this demand. One such place was the Andaman Islands, <a href="https://doi.org/10.1016/j.marpol.2022.105295">where I conducted my research between 2018 and 2019</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a man and two women sit on stools with a variety of fish for sale at their feet" src="https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498662/original/file-20221202-20-t9s5ng.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">Sharks and rays for sale at a fish market in southern India.</span>
<span class="attribution"><span class="source">(Zoya Tyabji)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Consumption preferences</h2>
<p>Locals in the Andaman Islands preferred consuming reef fish, due to the taste, tough skin and difficulty in cooking sharks and rays. However, as most of the fish caught in the Andaman Islands are exported, the consequent local shortages of reef fish led to locals consuming what was available.</p>
<p>Another factor in the rise in consumption was the migration of people from parts of mainland India and Southeast Asia to the Andaman Islands who consumed sharks and rays traditionally. Not all shark and ray species were preferred for consumption and trade: smaller sharks were preferred as the texture of their meat was softer.</p>
<p>One such example is from a community in Middle Andaman who started consuming nurse sharks due to their availability and declines of other reef fish. They locally call them “biscuit sharks” due to the texture of the shark when consumed. </p>
<p>There is a common belief in mainland India that milk sharks (<em>Rhizoprionodon acutus</em>) were especially beneficial to pregnant and lactating women. However, all sharks under a metre in length were misidentified as milk sharks.</p>
<p>Our research also found that there were consumption preferences when it came to rays. Those which were uniformly coloured (such as <em>Pateobatis jenkinsii</em> and <em>Pateobatis fai</em>) and had white meat were also preferred over spotted rays (<em>Himantura uarnak</em>) and those with black meat (all eagle rays and devil rays).</p>
<h2>Complex trade routes</h2>
<p>Local shark and ray consumption on the Andaman Islands is at a much smaller scale than the export of sharks and rays outside the islands. The trade routes for sharks and rays are complex, with each product having its own distinct supply chain.</p>
<p>Shark meat from smaller sharks (less than one metre in length) was sold in domestic markets on the Indian mainland. Other products sold included meat from larger sharks and rays, meat and leather from small sharks (individuals measuring less than one metre in length). </p>
<p>In international markets, demand was for products such as shark and ray meat from larger individuals, ray skin for the leather industry, gill plates from mobula rays for medicines, and shark liver oil for tonics.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a small shark rests on a rock" src="https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=320&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=320&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=320&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=402&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=402&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506988/original/file-20230130-24-m5ptoa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=402&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nurse sharks were locally referred to as biscuit sharks because of the texture of their meat after cooking.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Our results also suggested that a targeted stingray fishery is now developing on the islands to supply the high demand for meat on peninsular India. This is profitable due to the perceived high abundance of rays in the islands, the demand, and the lack of policies on stingrays. This is concerning as <a href="https://www.iucnssg.org/">stingrays are even more threatened than sharks</a>. </p>
<p>Further, the trade affects stakeholders differently. For example, small scale fishers informed us about the declines in shark populations in these areas, which also affects their livelihoods. However, fishers who have the resources to invest in boats and gear that can fish sharks from offshore areas perceive them to be abundant. This also causes conflict between stakeholder groups as those with networks and resources benefit more than others.</p>
<h2>Protecting sharks and rays</h2>
<p>While there are international regulations such as the <a href="https://cites.org/eng/disc/what.php">Convention on International Trade in Endangered Species of Wild Fauna and Flora</a> in place, our findings make it clear that there is an urgent need to regulate the domestic trade in India. </p>
<p>Additionally, increasing awareness of how consuming sharks and rays endangers them is important. Any regulations and policies should be developed with local communities whose livelihoods may be affected.</p>
<p>Understanding how and why sharks and rays are consumed and traded can inform where and how interventions should be made. Such studies also help us identify species most at risk.</p><img src="https://counter.theconversation.com/content/191984/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zoya Tyabji 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>Sharks and rays are traded for their meat, liver and other products. The global demand for these products has increased, and in India, the trade affects livelihoods and culture.Zoya Tyabji, PhD student, Biology, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1934572023-01-02T19:44:56Z2023-01-02T19:44:56ZWhen we swim in the ocean, we enter another animal’s home. Here’s how to keep us all safe<figure><img src="https://images.theconversation.com/files/501731/original/file-20221219-11129-flr0fc.jpg?ixlib=rb-1.1.0&rect=23%2C7%2C5176%2C3453&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Every summer, many Australians head to the ocean to swim, surf, sail, kayak, and walk along the beach. </p>
<p>But humans are not alone when we use the ocean. Fish, seals, dolphins, sharks, jellyfish, turtles, stingrays, cuttlefish, and birds often swim alongside us. When we enter the ocean we become part of an entangled web of animal relationships.</p>
<p>Encountering animals when we swim and surf in the ocean is fun and exciting. But sharing the water with animals also <a href="https://www.tandfonline.com/doi/full/10.1080/02614367.2022.2149842">comes with</a> the risk of stings, bites, frights, and injury to us. It can also bring harm to ocean wildlife.</p>
<p>By educating ourselves about marine life, humans can minimise risks to ourselves and the animals who call the ocean home.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/reel/CR5S0o8nMhO/?igshid=YmMyMTA2M2Y%3D","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>We can frighten animals – and they can scare us</h2>
<p>Despite how vulnerable we feel when swimming, our presence in the ocean can frighten or harm an animal. Animals may see us as a predator and alter their behaviour accordingly.</p>
<p>Fish, birds and small stingrays might swim off, and turtles might delay rising to the ocean’s surface to breathe. </p>
<p>Not all animals are frightened of humans. It’s a highlight when curious dolphins swim and play around us. But dolphins can attack humans or other animals if they <a href="https://www.ingentaconnect.com/content/cog/tme/2020/00000015/f0020003/art00008">feel threatened</a> - for example when feeding or protecting their young.</p>
<p>Humans can also be scared of animals in the water. This fear drives the use of shark nets off beaches or, less commonly, shark culls.</p>
<p>Shark nets are controversial – not least because they can <a href="https://theconversation.com/why-do-whales-keep-getting-tangled-in-shark-nets-and-what-should-you-do-if-you-see-it-happen-186468">entangle and kill</a> animals including turtles, non-target sharks, stingrays, and whales. </p>
<p>Even more controversial are shark culls, such as those <a href="https://theconversation.com/western-australias-shark-culls-lack-bite-and-science-21371">planned</a> for Western Australia in 2013 after a spate of fatal shark attacks. The plan was later <a href="https://www.theguardian.com/environment/2014/oct/24/wa-abandons-shark-culling-program-but-reserves-right-to-kill-again">abandoned</a>, after it was criticised as cruel and <a href="https://www.theguardian.com/world/2014/jul/04/wa-shark-cull-condemned-by-global-group-of-marine-scientists">lacking</a> scientific basis.</p>
<p>Killing or harming ocean animals so humans can have fun in the water raises all sorts of <a href="https://ro.uow.edu.au/asj/vol7/iss1/13/">questions</a> and moral dilemmas. So how else might we keep ourselves safe in the ocean?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/shark-nets-are-destructive-and-dont-keep-you-safe-lets-invest-in-lifeguards-127453">Shark nets are destructive and don't keep you safe – let's invest in lifeguards</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Hammerhead shark caught in net" src="https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501738/original/file-20221219-20-3cltme.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shark nets can kill non-target species, such as this hammerhead shark trapped off the Gold Coast.</span>
<span class="attribution"><span class="source">Sea Shepherd</span></span>
</figcaption>
</figure>
<h2>Learn about ocean animals</h2>
<p>Learning about what ocean animals you might encounter – and when – can help keep both people and animals safe.</p>
<p>Some animals are present year-round. But, as whale watchers and fisherman are well aware, many animals are more active in a particular seasons or only appear at certain times of the year. </p>
<p>For example, in cooler months in the waters off northern Australia, <a href="https://australian.museum/learn/animals/fishes/manta-ray-manta-birostris/">manta rays</a> are most active. <a href="https://search.informit.org/doi/pdf/10.3316/ielapa.702610524429802">Leopard sharks</a>, meanwhile, appear during warmer months in southeast Queensland and northeast New South Wales. </p>
<p>And from November until May or June, a variety of <a href="https://www.abc.net.au/news/2022-10-31/stinger-season-north-queensland-warning/101597638">marine stingers</a> can be found in the coastal waters of Far North Queensland. These include the potentially lethal box jellyfish. </p>
<p>Informing ourselves means we can take measures to keep safe. For example, people swimming in North Queensland in the warmer months are <a href="https://www.visitcairns.com.au/stingerseasoncairns.htm">advised to</a> swim at netted beaches, and wear wetsuits or stinger suits. Entering the water slowly also gives some marine stingers time to move away.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/want-to-avoid-a-bluebottle-sting-heres-how-to-predict-which-beach-theyll-land-on-179947">Want to avoid a bluebottle sting? Here's how to predict which beach they'll land on</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="sign depicting person caught by stinger" src="https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501736/original/file-20221219-11243-gy294k.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">Ocean-goers in North Queensland should know when marine stingers are about.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>When it comes to sharks, there are <a href="https://theconversation.com/shark-nets-are-destructive-and-dont-keep-you-safe-lets-invest-in-lifeguards-127453">growing calls</a> to adopt non-violent approaches to minimise risks to humans. This could include public education on, for example, links between fish seasons and shark activity. </p>
<p>Educating ourselves about ocean animals also helps us protect them.</p>
<p><a href="https://birdlife.org.au/projects/beach-nesting-birds">Shorebirds</a>, for instance, nest in spring and summer. This is prime beach time for people, too. Shorebird nests are shallow and vulnerable, and birds will often abandon their eggs when humans are around. Dogs and 4WDs pose an even <a href="https://theconversation.com/contested-spaces-saving-nature-when-our-beaches-have-gone-to-the-dogs-72078">bigger threat</a>.</p>
<p>If we know we’re sharing a beach with nesting shorebirds, we can take steps to ensure their safety, such as keeping our dogs on a leash and avoiding using dunes and other common nesting areas.</p>
<p>The annual migration of whales and their calves up and down our coasts is an exciting time to visit the beach and, if you’re lucky, to view a splashy show of breaching or water slapping. </p>
<p>But if you plan to go sailing or kayaking, be aware of rules around interacting with whales. They law states they can approach us, but we <a href="https://www.dcceew.gov.au/environment/marine/publications/australian-national-guidelines-whale-and-dolphin-watching-2017">must not</a> get too close to them.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/this-birds-stamina-is-remarkable-it-flies-non-stop-for-5-days-from-japan-to-australia-but-now-its-habitat-is-under-threat-165964">This bird's stamina is remarkable: it flies non-stop for 5 days from Japan to Australia, but now its habitat is under threat</a>
</strong>
</em>
</p>
<hr>
<p>If you’re not an experienced ocean user, or don’t know about the animals living in a particular place, talk to someone who is informed. </p>
<p>If you use beaches patrolled by surf lifesavers they can give you information about animals that might be present that day, such as sharks or jellyfish. They can also tell you about ocean conditions such as rips, currents and water quality.</p>
<p>If you do suffer a painful bluebottle or jellyfish sting, surf lifesavers may also provide basic <a href="https://beachsafe.org.au/surf-safety/marine-stingers">treatments</a> such as dousing the sting with hot water or vinegar.</p>
<p>If you’re planning to swim or surf at unpatrolled beaches – especially if they’re remote – pack a basic first aid kit including sunscreen, vinegar and instant ice packs.</p>
<p>And remember, enjoying time in the ocean with other poeple is <a href="https://journals.sagepub.com/doi/full/10.1177/0193723520928594">safer than</a> swimming alone.</p>
<figure class="align-center ">
<img alt="boy with boogie board and other swimmers" src="https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501764/original/file-20221219-13-4o0pxv.jpg?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">
<figcaption>
<span class="caption">It’s safer to swim with others than alone.</span>
<span class="attribution"><span class="source">Jason O'Brien/AAP</span></span>
</figcaption>
</figure>
<h2>Ensuring everyone enjoys the encounter</h2>
<p>Despite the risks, most human encounters with animals in the ocean are <a href="https://theconversation.com/why-going-for-a-swim-in-the-ocean-can-be-good-for-you-and-for-nature-150281">exciting</a> and positive. </p>
<p>Learning about the kinds of animals you might come across, as well as the best ways to interact with them, will help keep you safe – and make sure its a good experience for the animals too.</p><img src="https://counter.theconversation.com/content/193457/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Olive receives funding from The Australian Research Council. </span></em></p>Swimming and surfing in the ocean is fun and invigorating. But sharing the water with animals comes with risks to us and them.Rebecca Olive, Vice Chancellor's Senior Research Fellow, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1955932022-12-30T08:27:09Z2022-12-30T08:27:09ZFive human technologies inspired by nature – from velcro to racing cars<figure><img src="https://images.theconversation.com/files/500467/original/file-20221212-114007-p3m533.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3055%2C2024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many of humanity's innovations have taken inspiration from the natural world.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/great-white-shark-carcharodon-carcharias-surface-1706225779">Alessandro De Maddalena/Shutterstock</a></span></figcaption></figure><p>Nature has, over millions of years, evolved solutions to adapt to an array of challenges. As the challenges facing humanity become more complex, we are seeing inspiration being increasingly drawn from nature. </p>
<p>Taking biological processes and applying them to technological and design problems is called <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/bioinspiration">bioinspiration</a>. This is a fast-growing field, and our ability to copy nature is becoming more sophisticated. Here are five striking examples where nature has guided human innovation – and in some cases, could lead to even more exciting breakthroughs. </p>
<h2>1. Navigation</h2>
<p>Using <a href="https://www.nps.gov/subjects/bats/echolocation.htm">echolocation</a>, bats are able to fly in <a href="https://www.sciencedirect.com/science/article/pii/B9780128093245210316">complete darkness</a>. They emit sound and ultrasound waves, then monitor the time and magnitude of these waves’ reflections to create <a href="https://www.sciencedirect.com/science/article/abs/pii/S1071581907000833">three-dimensional spatial maps</a> of their surroundings. </p>
<p>The sensors that identify obstacles when reversing in many modern cars are <a href="https://www.techbriefs.com/component/content/article/tb/pub/features/articles/36374">inspired</a> by bat navigation. The direction and distance of an obstacle is calculated by emitting ultrasound waves which reflect off objects in a car’s path.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498452/original/file-20221201-6347-cjueta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The echolocation concept has been adopted by many technologies in modern life, Amin Al-Habaibeh, Author provided.</span>
</figcaption>
</figure>
<p>Sensory navigation technologies have also been <a href="https://www.sciencedirect.com/science/article/pii/S1877050915031312">proposed</a> to improve the safety of those with restricted vision. Ultrasound sensors installed on the human body would offer sound-based feedback of a person’s surroundings. This would allow them to move more freely by eliminating the threat of obstacles.</p>
<h2>2. Construction equipment</h2>
<p>Woodpeckers <a href="https://www.batzner.com/resources/blog-posts/why-woodpeckers-peck-and-prevent-them-from-pecking-your-house/#:%7E:text=They%20peck%20at%20wood%20to,is%20attached%20to%20a%20building.">knock</a> on the hard surface of trees to forage for food, build nests and attract a mate. Construction tools, such as handheld hydraulic and pneumatic hammers, mimic the <a href="https://apologeticspress.org/the-jackhammer-in-your-backyard-2315/">vibrating bill of a woodpecker</a> using a frequency roughly equivalent to a woodpecker’s hammering (<a href="https://www.sciencedirect.com/science/article/abs/pii/S1672652914600457">20 to 25 Hz</a>). </p>
<figure class="align-center ">
<img alt="A woodpecker feeding chicks in its nest in a hole of a tree." src="https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499263/original/file-20221206-25-zf8fph.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">Woodpeckers knock on the hard surface of trees to forage for food, build nests and attract a mate.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/great-spotted-woodpecker-dendrocopos-major-perched-2060062277">Vaclav Matous/Shutterstock</a></span>
</figcaption>
</figure>
<p>But the vibration of these power tools can damage the hands of construction workers. This can, in some cases, cause <a href="https://www.hse.gov.uk/mvr/topics/vibration.htm">vibration white finger</a>, a condition where sufferers experience permanent numbness and pain in their hands and arms. </p>
<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S0960982222009964">Research</a> is now studying how woodpeckers protect their brains from the impact of repeated drilling. One <a href="https://www.sciencedirect.com/science/article/abs/pii/S175161611830688X?via%3Dihub">study</a> found that woodpeckers have several impact-absorbing adaptions that other birds do not have. </p>
<p>Their skull is adapted to be tough and hard, and their tongue wraps around the back of the skull and anchors between their eyes. This protects a woodpecker’s brain by softening the impact of the hammering and its vibrations.</p>
<p>Research such as this is guiding the design of <a href="https://www.mdpi.com/2076-3417/11/22/10584/htm">shock absorbers and vibration control devices</a> to protect the users of such equipment. The same concept has also inspired innovations such as <a href="https://www.sciencedirect.com/science/article/pii/S2214785319341987">layered shock-absorbing structures</a> for building design.</p>
<h2>3. Building design</h2>
<p>Scallops are molluscs with a fan-shaped, corrugated external shell. The zig-zag shape of these <a href="https://www.sciencedirect.com/topics/engineering/corrugated-sheet">corrugations</a> strengthens the shell’s structure, enabling it to withstand high pressure under water.</p>
<p>The same process is used to increase the strength of a cardboard box, with corrugated paper material being glued between the two external cardboard layers. The introduction of a corrugated surface significantly increases a material’s strength, in the same way that folding a piece of paper into a zig-zag shape allows it to take an additional load.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=350&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=350&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=350&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=440&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=440&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498782/original/file-20221204-55844-i0v9vg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=440&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A folded piece of paper in a zig-zag shape could withstand heavy load. Amin Al-Habaibeh, Author provided.</span>
</figcaption>
</figure>
<p>The dome-shaped structure of a scallop’s shell also enables it to withstand significant loads. This structure is self-supporting as it distributes the weight evenly over the entire dome shape, reducing the load on a single point. This improves the structure’s stability without the need for reinforcing steel beams and has inspired the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0378778821003182">design of many buildings</a>, including St Paul’s Cathedral in London. </p>
<h2>4. Transport aerodynamics</h2>
<p>Sharks have two dorsal fins which provide several aerodynamic advantages. They <a href="https://dlnr.hawaii.gov/sharks/anatomy/fins-swimming/#:%7E:text=Dorsal%20fins%20stabilize%20the%20shark,and%20helping%20to%20conserve%20energy.">stabilise the shark</a> from rolling, while their aerofoil shape creates an area of low turbulence behind them and so increases the efficiency of the shark’s forward movement. </p>
<p>Shark fins have been replicated in motorised transportation. For example, racing cars use fins to both reduce turbulence when travelling at high speed and <a href="https://www.roadandtrack.com/motorsports/a28497386/shark-fin-race-car-wing-explained/">improve stability</a> when cornering. </p>
<p>Many road cars now have a small “shark fin” installed on their roof, which is used to integrate their <a href="https://natalexauto.com/blogs/natalex-auto-blog/what-is-the-shark-fin-on-the-roof-of-a-car">radio antenna</a>. This reduces drag compared to the traditional pole antenna.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498796/original/file-20221204-55991-d268zz.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">Shark-fin antenna in a modern car. Amin Al-Habaibeh. Author provided.</span>
</figcaption>
</figure>
<p>We have also taken inspiration from nature to increase the efficiency of aircraft flight. An owl’s wings act as a <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2020.1748">suspension system</a>; by changing the position, shape and angle of their wings, they are able to <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2020.1748">reduce the effect</a> of turbulence while in flight. And <a href="https://www.nationalgeographic.co.uk/science-and-technology/2021/03/owl-wings-may-hold-the-key-to-turbulence-proof-planes">research</a> into owl flight may open the door to turbulence-free air travel in the future.</p>
<h2>5. Velcro</h2>
<p>The hook-and-loop <a href="https://www.velcro.co.uk/blog/2018/06/how-do-velcro-brand-fasteners-work/#:%7E:text=Hook%20and%20loop%20fasteners%20have,and%20loop%20fastener%20will%20be.">fastening mechanism</a> of <a href="https://www.velcro.com/news-and-blog/2016/11/an-idea-that-stuck-how-george-de-mestral-invented-the-velcro-fastener/">velcro</a> was inspired by the ability of the burrs of burdock plants to fasten to human clothing.</p>
<p>Plants use burrs to <a href="https://homeguides.sfgate.com/plants-burrs-26416.html">attach seed pods</a> to passing animals and people, in order to disperse seeds over wider areas. Burrs possess small hooks that interlock with the small loops in soft material.</p>
<p>Velcro replicates this by using a strip lined with hooks together with a fabric strip. When pressed together, the hooks attach to the loops and fasten to one another. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=244&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=244&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=244&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=307&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=307&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498799/original/file-20221204-25475-ps5jqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=307&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hook and Loop structure under the microscope. Amin Al-Habaibeh, Author provided.</span>
</figcaption>
</figure>
<p>Velcro is used in a wide range of products worldwide. According to <a href="https://www.nasa.gov/offices/ipp/home/myth_tang.html#:%7E:text=Velcro%20was%20used%20during%20the,associated%20with%20the%20Space%20Program.">Nasa</a>, it was used in space during the Apollo missions from 1961 to 1972 to fix equipment in place in zero gravity.</p><img src="https://counter.theconversation.com/content/195593/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amin Al-Habaibeh 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>Humans often look to nature for the solutions to complex problems – here are five times where biological processes have inspired innovation.Amin Al-Habaibeh, Professor of Intelligent Engineering Systems, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.