tag:theconversation.com,2011:/global/topics/overfishing-4932/articlesOverfishing – The Conversation2024-03-07T19:03:24Ztag:theconversation.com,2011:article/2242302024-03-07T19:03:24Z2024-03-07T19:03:24ZFished for their meat and liver oil, many remarkable deep-water sharks and rays now face extinction<figure><img src="https://images.theconversation.com/files/580260/original/file-20240306-24-da5war.jpg?ixlib=rb-1.1.0&rect=19%2C173%2C4262%2C2156&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/six-gill-shark-pup-110832647">Shutterstock/Greg Amptman</a></span></figcaption></figure><p>The deep ocean, beyond 200 metres of depth, is the largest and one of the most complex environments on the planet. It covers 84% of the world’s ocean area and 98% of its volume – and it is home to a great diversity of species.</p>
<p>Yet it remains among the least studied places on Earth, with no comprehensive assessments of the state of deep-water biodiversity and no policy-relevant indicators to guide the taking of species targeted by fisheries. </p>
<p>This also applies specifically to deep-water sharks and rays, even though these species make up nearly half of the recognised diversity of all cartilaginous fishes (sharks, rays, and chimaeras) we know today. </p>
<p>Our <a href="https://www.science.org/doi/10.1126/science.ade9121">research</a> highlights how our growing impact on the deep ocean raises the threat to these species. </p>
<p>Using the <a href="https://www.iucn.org/">International Union for Conservation of Nature</a> Red List of Threatened Species, we show that the number of threatened deep-water sharks and rays has more than doubled between 1980 and 2005, following the emergence and expansion of deep-water fishing. </p>
<p>We estimate one in seven species (14%) are threatened with extinction. </p>
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Read more:
<a href="https://theconversation.com/sharks-and-rays-are-in-free-fall-more-than-one-third-are-threatened-with-extinction-from-overfishing-167329">Sharks and rays are in free fall: More than one-third are threatened with extinction from overfishing</a>
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<h2>Fishing for meat and oil</h2>
<p>Deep-water sharks and rays are in a group of marine vertebrates that are most sensitive to overexploitation. This is because of their long lifespans (possibly <a href="https://www.science.org/doi/full/10.1126/science.aaf1703">up to 450 years for the Greenland shark</a>, <em>Somniosus microcephalus</em>) and low reproduction rate (only <a href="https://www.iucnssg.org/publications-other.htmlhttps://www.iucnssg.org/publications-other.html">12 pups in a lifetime for the gulper shark</a>, <em>Centrophorus granulosus</em>). </p>
<p>These biological characteristics make them similar to formerly exploited, and now highly protected, marine mammals. </p>
<figure class="align-center ">
<img alt="Greenland shark in dark water" src="https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580036/original/file-20240305-21577-2siggc.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">The Greenland shark can live up to 450 years.</span>
<span class="attribution"><a class="source" href="https://oceanservice.noaa.gov/facts/greenland-shark.html">Wikimedia Comons/Hemming1952</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>The Greenland shark and the leafscale gulper shark (<em>Centrophorus squamosus</em>), for example, have population growth rates comparable to the sperm whale (<em>Physeter macrocephalus</em>) and the walrus (<em>Odobenus rosmarus</em>), respectively. Despite their known inherent vulnerability, there are very few species-specific management actions for deep-water sharks. </p>
<p>Our research shows that overfishing is the primary threat to deep-water sharks and rays. They are used for their meat and liver oil, which drives targeted fisheries but also incidental capture, meaning any accidental catches are retained by fisheries targeting other species. </p>
<p>In many nations, deep-water sharks and rays are regarded as a welcome catch because of the <a href="https://saveourseas.com/update/is-by-catch-responsible-for-the-decline-of-deep-sea-oil-sharks/">high value of their liver oil</a> and <a href="https://academic.oup.com/icesjms/article/80/3/578/6484966">high demand for skate meat</a>. These are not new trades, but the global expansion and diversification of use, particularly for shark liver oil, is a relatively new phenomenon. </p>
<figure class="align-center ">
<img alt="Gulper shark" src="https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580040/original/file-20240305-26-ioc67p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Deep-water sharks, such as this gulper shark, are used for meat and liver oil.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/okeanos/explorations/ex1811/logs/nov15/welcome.html">NOAA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Targeted shark liver oil fisheries are <a href="https://epubs.icar.org.in/index.php/IJF/article/view/92453">boom-and-bust fisheries</a>. They drive shark populations down and raise the extinction risk over short periods of time (less than 20 years). There is particular interest in shark liver oil for applications in cosmetics and human health products, including vaccine adjuvants. </p>
<p>This is despite a lack of evaluation of possible human health risks of using liver oil for medical purposes (deep-water sharks can bioaccumulate heavy metals and contaminants at concentrations at or above <a href="https://www.sciencedirect.com/science/article/abs/pii/S0025326X23013772">regulatory thresholds</a>). </p>
<h2>Need for global deep-water shark action</h2>
<p>There have been tremendous triumphs in shark conservation, including the regulation of the global trade in fins from threatened coastal and pelagic species. But deep-water sharks have been largely left out of conservation discussions. </p>
<p>The <a href="https://cites.org/eng">Convention on International Trade in Endangered Species of Wild Fauna and Flora</a> has yet to see a listing proposal for a deep-water shark or ray. </p>
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<img alt="A deepwater stingray, Plesiobatis daviesi" src="https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580257/original/file-20240306-28-9ocphi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&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">Deep-water sharks and rays, such as this stingray, have been left out of conservation discussions.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Plesiobatis_daviesi_cochin.jpg#/media/File:Plesiobatis_daviesi_cochin.jpg">Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>We call for trade and fishing regulations specific to deep-water sharks and rays to ensure legal, traceable and sustainable trade and to prevent their further endangerment. </p>
<p>There are presently limited ways of determining which species comprise internationally traded liver oil. It may be a byproduct of sustainable fisheries but the current lack of regulations could also be masking the trade of threatened species. </p>
<p>We also propose closures of areas important to deep-water sharks and rays to provide refuge from fishing and promote recovery and long-term survival. Nearly every deep-water shark is threatened by incidental capture. </p>
<p><a href="https://ices-library.figshare.com/articles/report/Report_of_the_Working_Group_on_Elasmobranch_Fishes_WGEF_/24190332">Retention bans have been implemented</a> in some regions as a mitigation strategy, including European waters managed under the <a href="https://ices-library.figshare.com/">International Council for the Exploration of the Sea</a>. But they don’t prevent the mortality of prohibited species that are released after being brought to the surface from great depths. </p>
<p>We need efforts to prevent capture in the first place. There is now a global push to protect 30% of the ocean by 2030 through the <a href="https://www.cbd.int/gbf/targets">Convention on Biological Diversity</a>, which New Zealand has ratified. </p>
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Read more:
<a href="https://theconversation.com/oceanic-sharks-and-rays-have-declined-by-71-since-1970-a-global-solution-is-needed-154102">Oceanic sharks and rays have declined by 71% since 1970 – a global solution is needed</a>
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<p>Our work shows protecting 30% of the deep ocean (200-2000m) would provide around 80% of deep-water shark species with at least partial spatial protection across their range. If a worldwide prohibition of fishing below 800m were to be implemented, it would provide 30% vertical refuge for one third of threatened deep-water sharks and rays.</p>
<p>Even though the extinction risk for these species is much lower than that of their shallow-water relatives, their potential for recovery from overexploitation is much reduced because of their long lifespans and low fecundity. One <a href="https://academic.oup.com/icesjms/article/76/7/2318/5506076">study</a> estimated it would take 63 years or more for the little gulper shark (<em>Centrophorus uyato</em>) to recover to just 20% of its original population size. </p>
<p>We know many shark populations around the world <a href="https://www.cell.com/current-biology/pdf/S0960-9822(21)01198-2.pdf">are in trouble</a>. Threatened deep-water sharks have little chance of recovery without immediate action. Now is the time to implement effective conservation actions in the deep ocean to ensure half of the world’s sharks and rays have a refuge from the global extinction crisis.</p><img src="https://counter.theconversation.com/content/224230/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brittany Finucci is affiliated with the IUCN Species Survival Commission Shark Specialist Group.</span></em></p><p class="fine-print"><em><span>Cassandra Rigby is affiliated with the IUCN Species Survival Commission Shark Specialist Group.</span></em></p>Long lifespans and slow reproduction rates make deep-water sharks and rays as vulnerable to overexploitation as whales once were. We must place them under protection to avoid extinctions.Brittany Finucci, Fisheries Scientist, National Institute of Water and Atmospheric ResearchCassandra Rigby, Adjunct Senior Research Fellow, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2246072024-03-06T19:07:52Z2024-03-06T19:07:52ZSharks, turtles and other sea creatures face greater risk from industrial fishing than previously thought − we estimated added pressure from ‘dark’ fishing vessels<figure><img src="https://images.theconversation.com/files/580177/original/file-20240306-22-3smwaf.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C2977%2C1998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Seabirds like this sooty shearwater can drown when they become tangled in drift nets and other fishing gear. </span> <span class="attribution"><a class="source" href="https://flic.kr/p/dj3H6v"> Roy Lowe, USFWS/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>My colleagues and I mapped activity in the northeast Pacific of “dark” fishing vessels – boats that turn off their location devices or lose signal for technical reasons. In <a href="https://www.science.org/doi/10.1126/sciadv.adl5528">our new study</a>, we found that highly mobile marine predators, such as sea lions, sharks and leatherback sea turtles, are significantly <a href="https://news.stanford.edu/2019/03/13/tunas-sharks-ships-sea/">more threatened than previously thought</a> because of large numbers of dark fishing vessels operating where these species live. </p>
<p>While we couldn’t directly watch the activities of each of these dark vessels, <a href="https://www.theguardian.com/environment/2022/nov/02/at-least-6-percent-global-fishing-likely-as-ships-turn-off-tracking-devices-study">new technological advances</a>, including satellite data and machine learning, make it possible to estimate where they go when they are not broadcasting their locations. </p>
<p>Examining five years of data from fishing vessel location devices and the habitats of 14 large marine species, including seabirds, sharks, turtles, sea lions and tunas, we found that our estimates of risk to these animals increased by nearly 25% when we accounted for the presence of dark vessels. For some individual predators, such as albacore and bluefin tunas, this adjustment increased risk by over 36%. The main hot spots were in the Bering Sea and along the Pacific coast of North America. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/bjFSgr_B38I?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Bycatch, or accidental take, is the leading threat to some endangered marine species.</span></figcaption>
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<h2>How we did our work</h2>
<p>Fishing boats use <a href="https://globalfishingwatch.org/faqs/what-is-ais/">Automatic Identification System</a>, or AIS, to avoid colliding with each other. Their AIS signals bounce off satellites to reach nearby ships. </p>
<p>This data is a valuable tool for <a href="https://www.cbsnews.com/detroit/news/study-choosing-fish-may-be-killing-sharks/">mapping risk at sea</a> and <a href="https://www.bbc.com/news/science-environment-43169824">understanding the footprints of fishing fleets</a>. AIS data captures an estimated <a href="http://dx.doi.org/10.1126/science.aao564">50% to 80%</a> of fishing operations occurring more than 100 nautical miles from shore.</p>
<p>But in some areas, vessels’ AIS signals can’t reach the satellites, either because reception is poor or many boats are crowded together – much as cellphones can have difficulty sending text messages in remote wildness or in crowded stadiums. And just as location tracking can be disabled on phones, fishing vessels can intentionally <a href="https://theconversation.com/when-fishing-boats-go-dark-at-sea-theyre-often-committing-crimes-we-mapped-where-it-happens-196694">disable their AIS</a> if they want to hide their location. Boats that do this may be engaged in criminal activities, such as <a href="https://www.penguinrandomhouse.com/books/538736/the-outlaw-ocean-by-ian-urbina/">illegal fishing or human trafficking</a>.</p>
<p>We calculated how much risk dark vessels pose to marine life by overlapping their activity with the modeled habitats of 14 highly mobile marine predators. Using the same method, we also calculated how much risk observable fishing vessels that broadcast their locations pose to marine life. These two calculations allowed us to understand the additional risk from dark fishing vessels.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A seal on a beach, with a rope wrapped around it and connected to a large orange float beside the animal." src="https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579990/original/file-20240305-26-vf2vcl.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>
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<span class="caption">A Hawaiian monk seal entangled on a large fishing float.</span>
<span class="attribution"><a class="source" href="https://photolib.noaa.gov/Collections/Fisheries/Other/emodule/1054/eitem/61324">Doug Helton, NOAA/NOS/ORR/ERD</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>Why it matters</h2>
<p>We know that many sea creatures, including endangered species, are <a href="https://www.msc.org/en-us/what-we-are-doing/oceans-at-risk/overfishing">killed by overfishing</a>, <a href="https://www.latimes.com/opinion/op-ed/la-oe-welch-sea-turtles-swordfish-climate-change-20190610-story.html">accidental catch</a> and <a href="https://www.fisheries.noaa.gov/west-coast/marine-mammal-protection/west-coast-large-whale-entanglement-response-program">entanglement in fishing gear</a>. More overlap between wildlife and fishing boats means that those harmful impacts are more likely to happen. </p>
<p>Even considering only <a href="https://globalfishingwatch.org/map/index?start=2023-11-25T00%3A00%3A00.000Z&end=2024-02-25T00%3A00%3A00.000Z&latitude=19&longitude=26&zoom=1.5">observable fishing boats broadcasting their positions</a>, the presence of boats signals considerable risk for marine life. For example, <a href="https://www.fisheries.noaa.gov/species/california-sea-lion">California sea lions</a> forage in Pacific coastal waters from the Canadian border to Baja California and are accidentally caught by boats fishing for hake and halibut. We found observable fishing activity in over 45% of the sea lions’ habitat. </p>
<p>In another example, migratory <a href="https://www.adfg.alaska.gov/index.cfm?adfg=salmonshark.main">salmon sharks</a> feed on salmon near Alaska’s Aleutian Islands during the summer and breed in warmer waters off the coasts of Oregon and California during the winter. Along their journey, salmon sharks are accidentally caught in fishing nets and longlines. We detected observable vessel fishing activity in nearly one-third of salmon shark habitat. </p>
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<a href="https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&rect=31%2C0%2C5169%2C3461&q=45&auto=format&w=1000&fit=clip"><img alt="Dozens of fishing boats move out of an urban harbor" src="https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&rect=31%2C0%2C5169%2C3461&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579983/original/file-20240305-28-en5un3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Fishing boats head out for the East China Sea in Zhoushan, Zhejiang Province, China.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/fishing-boats-set-sail-in-the-morning-to-east-china-sea-for-news-photo/1340823231">Shen Lei/VCG via Getty Images</a></span>
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<p>Our findings indicate that such threats are higher when dark fishing boats are present. Estimates of risk to California sea lions and salmon sharks increased by 28% and 23%, respectively, when we accounted for dark vessels.</p>
<p>This information could affect fishery regulation. For example, regulators <a href="https://www.fisheries.noaa.gov/feature-story/fish-stock-assessment-101-part-2-closer-look-stock-assessment-models">use risk information</a> to set catch limits for species such as tuna; higher risk could mean that catch limits need to be lower. </p>
<p>For species such as sea lions and salmon sharks that are accidentally caught by fishermen, higher risk levels could indicate that fishing boats should use more selective gear. California is currently acting on this issue by helping fishermen phase out use of <a href="https://opc.ca.gov/2022/11/phase-out-drift-gillnets/">large-mesh drift gill nets</a> in state waters. These nets, which hang like curtains in the water, catch <a href="https://www.fao.org/3/T0502E/T0502E01.htm">many other fishes along with the target species</a>. </p>
<p>Accounting for dark vessels is particularly important in international waters where boats from multiple countries operate, because AIS data is one of the most complete sources of fishing activity across nations. Tracking dark vessels can help make this information as comprehensive as possible and provide insights into the multinational impacts of fishing. </p>
<p>Our study does not account for vessels that do not use any vessel tracking system, or that use systems other than AIS. Therefore, our risk calculations likely still underestimate the true impact of fisheries on marine predators. </p>
<h2>What’s next</h2>
<p>The world’s oceans are rich in life but poor in data, although this is changing. High-resolution <a href="https://www.smithsonianmag.com/smart-news/satellite-maps-reveal-rampant-fishing-untracked-dark-vessels-oceans-180983539/">satellite imagery</a> may soon offer even more information on risk from dark vessels. </p>
<p>President Joe Biden and other global leaders have pledged to protect <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2023/03/21/fact-sheet-biden-harris-administration-takes-new-action-to-conserve-and-restore-americas-lands-and-waters/">30% of the ocean by 2030</a>. Better data on human-wildlife interactions at sea can help ensure that new protected areas are in the right places to make a difference.</p><img src="https://counter.theconversation.com/content/224607/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heather Welch receives funding from NOAA's Office of Law Enforcement. </span></em></p>The toll on wildlife from illegal fishing, bycatch and entanglement in fishing gear is likely underestimated, because it doesn’t account for ‘dark’ fishing vessels, a new study finds.Heather Welch, Researcher in Ecosystem Dynamics, University of California, Santa CruzLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189772024-02-15T22:07:25Z2024-02-15T22:07:25Z8 ways that stopping overfishing will promote biodiversity and help address climate change<figure><img src="https://images.theconversation.com/files/576010/original/file-20240215-18-gqysb.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3804%2C2545&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Schools of jackfish pictured in the ocean off Losin, Thailand. Overfishing is a contributing factor in global climate change.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Amid the escalating threats of a warming world, and with the latest annual United Nations global climate conference (COP28) behind us, there is one critical message that’s often left out of the climate change discourse. Halting overfishing is itself effective climate action.</p>
<p>This argument is the logical conclusion of a plethora of studies that unequivocally assert that stopping overfishing isn’t just a necessity, it’s a win-win for ocean vitality, climate robustness and the livelihoods reliant on sustainable fisheries.</p>
<p>The intricate relationship between climate change and ocean ecosystems was the subject of recent collaborative research — led by researchers at the University of British Columbia — that highlighted the crucial links between overfishing and climate change. </p>
<h2>Finding the connections</h2>
<p>Our collaborative team of international researchers applied a host of methodologies ranging from literature reviews to quantitative and quality analysis. The findings of <a href="https://doi.org/10.3389/fmars.2023.1250449">this research</a> illuminate eight key multifaceted impacts.</p>
<p>1 — Ending overfishing <a href="https://doi.org/10.3389/fmars.2020.00523">isn’t merely an ecological imperative but a vital climate action</a>. Doing so would bolster marine life resilience in the face of climate shifts and reduce associate carbon emissions.</p>
<p>2 — Large subsidized fishing boat fleets can <a href="https://doi.org/10.1126/science.abm1680">actually be a burden on small-scale fisheries, leaving them disproportionately vulnerable to shocks</a>. In turn, overfishing not only depletes resources but also escalates carbon emissions, <a href="https://doi.org/10.3389/fmars.2022.768784">intensifying climate impacts on these fisheries and their communities, particularly women</a>.</p>
<p>Additionally, the <a href="https://doi.org/10.3389/fmars.2022.802762">vulnerability of shellfish fisheries to climate stressors further underscores the importance of adaptive strategies</a> tailored to local conditions. </p>
<p>3 — Success stories, like the recovery of European hake stocks, <a href="https://doi.org/10.3389/fmars.2022.788339">reveal a direct tie between stock recuperation and reduced emissions intensity from fisheries</a>. <a href="https://theconversation.com/how-to-stay-hopeful-in-a-world-seemingly-beyond-saving-210415">We must champion and also learn from these successes</a>.</p>
<p>4 — Ecosystem-based fisheries management reverses the “order of priorities so that management starts with ecosystem considerations rather than the maximum exploitation of several target species.” </p>
<p>Ecosystem-based fisheries management has considerable potential to enhance sustainable catches while fostering carbon sequestration. This is perhaps <a href="https://doi.org/10.3389/fmars.2022.879998">best exemplified by the successful implimentation of ecosystem-based fisheries management in the western Baltic Sea</a>.</p>
<p>5 — <a href="https://doi.org/10.3389/fmars.2021.770805">Heavy metal pollution in the ocean — such as mercury or lead waste — intensifies the negative impacts of warming and overfishing</a>. This pollution reinforces the need for developing multifaceted regulations based around ecosystem and ocean sustainability solutions. </p>
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Read more:
<a href="https://theconversation.com/flipping-indigenous-regional-development-in-newfoundland-upside-down-lessons-from-australia-218298">Flipping Indigenous regional development in Newfoundland upside-down: lessons from Australia</a>
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<p>6 — Overfishing <a href="https://doi.org/10.3389/fmars.2021.597385">exacerbates climate and biodiversity threats</a>. Climate change contributes to less defined and predictable seasons <a href="https://theconversation.com/how-climate-change-induced-stress-is-altering-fish-hormones-with-huge-repercussions-for-reproduction-213140">and is causing reproductive challenges</a> and the <a href="https://theconversation.com/climate-change-is-further-reducing-fish-stocks-with-worrisome-implications-for-global-food-supplies-217428">propagation of diseases in fish populations</a> — among other issues.</p>
<p>Adding to these problems, <a href="https://doi.org/10.1016/j.tree.2007.07.001">overfishing itself is altering ecological dynamics, modifying habitats and opening new pathways for invasive species</a>. These compounding crises further exacerbate the impacts of overfishing on marine ecosystems while at the same time making fish populations more vulnerable to climate change.</p>
<p>The above factors all combine to reduce the catch potential in any given ecosystem. In turn, fishers are forced to venture farther and deeper in the ocean to fish — increasing carbon emissions, personal risk factors to fishers and <a href="https://www.greenmatters.com/p/what-is-bycatch">bycatch</a> concerns. </p>
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<img alt="A dead shark is seen tangled in a fishing net." src="https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576013/original/file-20240215-24-d1h82g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&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">Reduced fish catches can lead to fishers going farther, and deeper, out to sea to find fish — with a host of associated consequences.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<p>7 — International fisheries management must play a central role in promoting biodiversity and retaining the ocean’s carbon sequestration potential. While 87 nations have signed the UN’s <a href="https://doi.org/10.3389/fmars.2022.764609">Biodiversity of Areas Beyond National Jurisdiction Treaty</a> (also known as the High Seas Treaty), only one has ratified it. This treaty must be fully ratified and its effective implementation should be contingent upon the creation of marine protected areas that cover at least 30 per cent of the high seas.</p>
<p>8 — The ocean has huge carbon sequestration potential. <a href="https://doi.org/10.3389/fmars.2022.800972">Shifting from the generally accepted maximum of sustainable yield management to maximizing carbon sequestration in fisheries management could further advance climate goals</a>.</p>
<p>Future regulations should allocate a percentage of the annual fish quota to maintain the carbon sequestration function of marine animals. Simply put, beyond just being food, fish stocks serve vital carbon sequestration and biodiversity services that directly benefit humanity. Future regulations should reflect this reality.</p>
<h2>A simple goal</h2>
<p>This joint collaborative research underscores the urgency of this issue. Ending overfishing isn’t just an ecological imperative but a linchpin for climate action. Furthermore, fisheries aren’t mere victims in these dynamics, but have real agency to play a pivotal role in either exacerbating or mitigating climate change.</p>
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Read more:
<a href="https://theconversation.com/the-future-of-fishing-and-fish-and-the-health-of-the-ocean-hinges-on-economics-and-the-idea-of-infinity-fish-182749">The future of fishing and fish — and the health of the ocean — hinges on economics and the idea of 'infinity fish'</a>
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<p>An ideal governance framework would focus on managing ecosystems with considerations for their diverse benefits, based on the best evidence available. Regulation of fisheries, while controversial, is essential to not overly exploit such a valuable public resource.</p>
<p>As we gear up to the next COP, we would do well to remember these conclusions. Without nurturing ocean life, addressing climate change becomes an uphill battle. Sustainable fisheries management is not just an ecological necessity. It is also the cornerstone of a resilient, sustainable future.</p><img src="https://counter.theconversation.com/content/218977/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rashid Sumaila receives funding from the Social Sciences and Humanities Research Council and the non-governmental organization Our Fish.</span></em></p>Recent research shows how reducing overfishing is both an ecological imperative and a critical means to addressing climate change.Rashid Sumaila, Director & Professor, Fisheries Economics Research Unit, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225112024-02-02T11:04:44Z2024-02-02T11:04:44ZGovernments spend US$22 billion a year helping the fishing industry empty our oceans. This injustice must end<figure><img src="https://images.theconversation.com/files/572830/original/file-20240201-27-sdoziy.jpg?ixlib=rb-1.1.0&rect=2%2C0%2C1370%2C770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/drone-view-of-fishing-trawler-on-sea-5829126/">Pok Rie/Pexel</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Overfishing has dire consequences for ocean health and for the millions of people who depend on fish for food and wellbeing. Globally, catch has been steadily <a href="https://www.nature.com/articles/ncomms10244">declining</a> since the 1990s. It’s a trend that’s likely to continue if we fail to act now.</p>
<p>Nearly all governments, including Australia’s, subsidise their fishing industries. Financial support comes in many forms, from taxpayer-funded fuel to reduced boat-building costs. These subsidies are harmful because they encourage overfishing. Some of the most environmentally damaging and least efficient fishing activities, such as <a href="https://www.sciencedirect.com/science/article/abs/pii/S0308597X09001663">bottom trawling</a> and <a href="https://www.science.org/doi/full/10.1126/sciadv.aat2504">distant water fishing</a>, would become unprofitable and cease without government <a href="https://archives.nereusprogram.org/ask-an-expert-why-is-the-global-fishing-industry-given-35-billion-in-subsidies-each-year/">subsidies</a>. </p>
<p>Scientists worldwide are rallying for stringent regulations to eliminate harmful fisheries subsidies, which totalled a whopping <a href="https://www.sciencedirect.com/science/article/pii/S0308597X19303677">US$22 billion</a> in 2018. Safeguarding the ocean will strengthen food security and allow more equitable distribution of marine resources.</p>
<p>Trade ministers from around the world are set to convene later this month in Abu Dhabi at a key meeting of the World Trade Organization (WTO). In an <a href="https://www.nature.com/articles/s44183-024-00042-0">open letter</a> published today, we are among 36 marine experts calling on the WTO to adopt ambitious regulations promoting fisheries sustainability and equity, and to eliminate harmful fisheries subsidies.</p>
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Read more:
<a href="https://theconversation.com/putting-an-end-to-billions-in-fishing-subsidies-could-improve-fish-stocks-and-ocean-health-163470">Putting an end to billions in fishing subsidies could improve fish stocks and ocean health</a>
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<h2>A long-awaited agreement</h2>
<p>International pressure from scientists helped to broker an earlier agreement on fishing subsidies, which is yet to be ratified. </p>
<p>In October 2021, 300 experts published an <a href="https://www.science.org/doi/10.1126/science.abm1680">article in Nature</a> calling for an end to harmful subsidies in the fishing sector. </p>
<p>After decades of fruitless negotiations, the WTO finally reached an <a href="https://www.wto.org/english/tratop_e/rulesneg_e/fish_e/fish_factsheet_e.pdf">agreement on fisheries subsidies</a> in June 2022. </p>
<p>Once ratified by two-thirds of WTO members, this agreement will partially address the United Nations <a href="https://indicators.report/targets/14-6/">Sustainable Development Goal Target 14.6</a> to eliminate harmful subsidies.</p>
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<a href="https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man in a suit brings down the gavel after agreement was reached on fisheries subsidies at the WTO meeting in 2022." src="https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572831/original/file-20240201-17-tiyvdp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The gavel goes down after members reached an agreement on fisheries subsidies, Geneva, 17 June 2022.</span>
<span class="attribution"><a class="source" href="https://www.wto.org/english/thewto_e/minist_e/mc12_e/photos_e.htm">WTO/Jay Louvion</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Unfortunately, while this agreement is historic, it is narrow. It only prohibits member governments from financing illegal fishing activities and the exploitation of already overfished stocks. But it’s obvious illegal fishing should be banned and the focus on overfished stocks is too little, too late. </p>
<p>Experts argue the agreement fails to specifically address harmful subsidies across global fisheries and as such only affects a <a href="https://oceana.org/blog/the-wto-agreement-saves-face-but-does-it-save-fish/">trivial component</a> of subsidy-driven exploitation. The subsidies that reduce operating costs and increase fishing capacity, allowing vessels to travel further and remain at sea longer, remain in place. </p>
<h2>Fisheries subsidies affect more than just fish</h2>
<p>Scientists have been <a href="https://www.nature.com/articles/s43016-021-00451-1">sounding the alarm</a> for decades. Many published studies document the <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020239">destabilising effects</a> of fisheries subsidies on ecosystems. In addition to impacting biodiversity and ecosystems, subsidies also increase the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0921800921001154">CO₂ emissions</a> that contribute to climate change.</p>
<p>More recently, studies have also applied a social perspective to this issue. Seafood lifts millions of people out of hunger, malnutrition and poverty. Yet more people will lose a secure <a href="https://www.nature.com/articles/534317a">source of food and nutrients</a> if fish stocks continue to decline due to industrial overfishing. </p>
<p>Research shedding light on the concept of “<a href="https://www.sciencedirect.com/science/article/pii/S0308597X20302529">equity</a>” shows subsidies don’t just harm the ocean, they also affect human <a href="https://www.worldwildlife.org/stories/5-ways-harmful-fisheries-subsidies-impact-coastal-communities">communities</a>. These communities are largely in developing countries which are rarely the source of harmful fisheries subsidies. Rather, their waters are exploited by <a href="https://oceana.org/wp-content/uploads/sites/18/OceanaDWF_FinalReport.pdf">foreign vessels</a> supported by wealthy governments’ fisheries subsidies.</p>
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<a href="https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person wearing gloves, bending down to handle drying squid on a fish net" src="https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572832/original/file-20240201-25-bknp4o.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">Fisheries contribute to livelihoods and food security of millions of people.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/person-drying-squid-on-fishnet-13243896/">Jimmy Liao/Pexel</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Fisheries subsidies foster unfair competition not only among countries but also between industrial and community led fishing fleets. In the <a href="https://www.nature.com/articles/s44183-023-00031-9">Indian Ocean</a>, the level of subsidies provided to industrial fisheries corresponds to the amount of seafood exported to international markets, largely supplying rich and food-secure countries. This shows governments are deliberately empowering their industrial fleets to fish for seafood largely exported and consumed elsewhere, instead of sustaining fisheries providing food for locals. </p>
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Read more:
<a href="https://theconversation.com/fisheries-subsidies-fuel-ocean-depletion-and-hurt-coastal-communities-142260">Fisheries subsidies fuel ocean depletion and hurt coastal communities</a>
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<h2>The good, the bad and the ugly</h2>
<p>While most nations contribute to harmful subsidies, <a href="https://oceana.org/wp-content/uploads/sites/18/994812/Oceana_Summary6-22.pdf">ten nations</a> are responsible for 70% of this unsustainable financing. Chief among them are China, Japan and the European Union, reflecting the significant size of their distant water fishing fleets that typically access the resources of less-developed nations.</p>
<p>In contrast, <a href="https://www.sciencedirect.com/science/article/pii/S0308597X19303677?via%3Dihub">Australia</a> contributes only 0.1% of global harmful subsidies. Only 6% of Australia’s annual US$400 million in fisheries subsidies is considered harmful. While Australia should give attention to its ongoing annual taxpayer contribution of US$25 million to the fishing sector, it is well placed to demonstrate global leadership on how fishing can deliver sustainable and equitable outcomes without harmful subsidies.</p>
<h2>An essential opportunity</h2>
<p>A <a href="https://www.wto.org/english/thewto_e/minist_e/mc13_e/mc13_e.htm">second wave</a> of negotiations on fisheries subsidies is expected during the WTO Ministerial Conference this February in Abu Dhabi. This conference represents an invaluable opportunity to better protect the ocean. </p>
<p>In anticipation of this meeting, <a href="https://www.nature.com/articles/s44183-024-00042-0">we are urging nations</a> to adopt more ambitious regulations that eliminate harmful subsidies, prioritising fisheries sustainability and ocean equity. </p>
<p>Harmful fisheries subsidies are not only unsustainable but profoundly unfair. Based on the extensive body of evidence, the WTO should agree to eliminate harmful subsidies once and for all.</p><img src="https://counter.theconversation.com/content/222511/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vania Andreoli received funding for her PhD research from the Australian Government Research Training Program Scholarship and The Jock Clough Marine Foundation through the Oceans Institute Robson and Robertson Award. </span></em></p><p class="fine-print"><em><span>Dirk Zeller supervises Vania Andreoli’s PhD, so his lab has indirectly received funding for this doctoral research from the Australian Government and the Jock Clough Marine Foundation.</span></em></p><p class="fine-print"><em><span>Jessica Meeuwig supervises Vania Andreoli's PhD so her lab has indirectly received funding for this doctoral research from the Australian Government and the Jock Clough Marine Foundation. </span></em></p>Governments all over the world are propping up overfishing. Now scientists have penned an open letter calling on trade ministers to implement stricter regulations against harmful fisheries subsidies.Vania Andreoli, PhD Candidate, The University of Western AustraliaDirk Zeller, Professor & Director, Sea Around Us - Indian Ocean, 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/2219662024-01-29T00:20:35Z2024-01-29T00:20:35ZSediment runoff from the land is killing NZ’s seas – it’s time to take action<p>The fishers at Separation Point, between Golden Bay and Tasman Bay in New Zealand’s northwest South Island, used to be cautious. Something they called “hard coral” would tear their nets. If you dived down about 30 metres, you could see why: extensive reefs.</p>
<p>These reefs were constructed by <a href="https://www.sciencelearn.org.nz/resources/147-bryozoans">bryozoans</a>, tiny polyp-like creatures that cooperate to build large, branching colonies. They are similar to corals but live in deeper and cooler water.</p>
<p>The reefs at Separation Point were gorgeous and biodiverse. They provided shelter for small animals such as oysters and young fish. In 1980, the world’s first bryozoan-based fishing exclusion area was created to protect them: 146 square kilometres of seafloor was closed to most fishing, from the coastline to a depth of about 50 metres.</p>
<p>It went well at first. A 1983 study from the National Institute of Water and Atmospheric Research (<a href="https://niwa.co.nz/">NIWA</a>) of just one reef found 37 species of bryozoans and another 39 invertebrate species, plus numerous fish. In 2008, a <a href="https://niwa.co.nz/publications/water-and-atmosphere/vol16-no3-september-2008/effects-of-a-30-year-fishing-ban">study comparing fished and unfished areas</a> off Separation Point found more biodiversity where fishing had been limited.</p>
<p>Alas, subsequent developments have not been so kind. Land clearance for agriculture and forestry since human occupation has resulted in a ten-fold increase in sediment runoff in the area. </p>
<p>Thick beds of mud and silt have built up, destroying and burying the reefs. A <a href="https://www.stuff.co.nz/environment/128742534/protected-fish-nursery-wiped-out-by-mud">survey of the same area</a> in 2021 found flat mud deposits, with the occasional small, dead bryozoan sticking up. No fish remained in this marine ghost town.</p>
<h2>Part of a bigger picture</h2>
<p>These days it’s hard to escape news that the ocean is in trouble. Warming waters cause heatwaves that bleach corals. Fish and sharks appear where they never used to. Plastic is everywhere, including the stomachs of dolphins and penguins. Overfishing is causing populations to crash.</p>
<p>Meanwhile, sea levels are rising, dredging and mining are destroying ecosystems, while underwater engine noise and artificial light are changing how animals behave. Even the fundamental chemistry of seawater is changing as CO₂ dissolves in it. UNESCO’s <a href="https://oceanliteracy.unesco.org/?post-types=all&sort=popular">Ocean Literacy Portal</a> reads like an obituary.</p>
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<strong>
Read more:
<a href="https://theconversation.com/plastic-pollution-in-some-nz-lakes-is-comparable-to-northern-hemisphere-lakes-in-highly-populated-areas-global-study-finds-209509">Plastic pollution in some NZ lakes is comparable to northern hemisphere lakes in highly populated areas, global study finds</a>
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<p>But there’s another problem often left off that grim list: sediment runoff. When people remove trees, build roads and overstock paddocks, sand, mud and silt flow into the sea.</p>
<p>The resulting damage to coastal ecosystems gets little press, despite being described by the US National Oceanic and Atmospheric Administration as the <a href="https://oceanservice.noaa.gov/facts/pollution.html">greatest single source of pollution</a> in the world’s waterways and coasts. </p>
<p>The first objective of the <a href="https://www.doc.govt.nz/about-us/science-publications/conservation-publications/marine-and-coastal/new-zealand-coastal-policy-statement/new-zealand-coastal-policy-statement-2010/">New Zealand Coastal Policy Statement</a> in 2010 was to maintain and restore marine water quality. But that’s far from what we have today.</p>
<p>Dark waters, turbid with silt, affect marine life. We are increasingly aware of the changes in seaweed cover around New Zealand, from damage to kelp canopies to changes in phytoplankton. Seaweeds need light and clear waters.</p>
<p>Bryozoans, barnacles, oysters, cockles and scallops are suffering too. They literally starve to death by collecting dirt particles rather than food. Their delicate feeding tentacles are damaged or clogged, while their neighbours (such as pāua) are smothered or buried.</p>
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<strong>
Read more:
<a href="https://theconversation.com/nzs-vital-kelp-forests-are-in-peril-from-ocean-warming-threatening-the-important-species-that-rely-on-them-212956">NZ’s vital kelp forests are in peril from ocean warming – threatening the important species that rely on them</a>
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</em>
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<h2>New Zealand’s disproportionate problem</h2>
<p>Sediment runoff is most likely in wet places with high and regular rainfall, prone to being disturbed by storms and earthquakes, and with steep slopes, young rocks and soils. Agricultural land is a particularly strong source of sediment to waterways. Sound like somewhere you know?</p>
<p>Aotearoa New Zealand is eroding into the sea right under our feet. Over 200 million tonnes of sediment are <a href="https://niwa.co.nz/news/reducing-sedimentation">transported by rivers to the sea</a> each year, making fine sediment the most important and widespread water contaminant in this country.</p>
<p>Despite covering only 0.2% of global land area, the Ministry for the Environment <a href="https://environment.govt.nz/publications/new-zealands-land-at-a-glance-our-land-2018/">reported in 2018</a> that New Zealand contributes 1.7% of the sediment to the world’s oceans.</p>
<p>Removal of forest and well-rooted plants, overgrazing and construction all result in sediment washing into the sea. Excavating old soils containing now-outlawed pollutants such as DDT, tin or lead exacerbates the problem.</p>
<p>Under the Resource Management Act, regional councils have the authority to prevent discharge of contaminants into water, and the responsibility to manage catchments to minimise sediment getting to the sea. Murky coastal waters suggest they’re not coping with this task. </p>
<h2>Action and policy needed</h2>
<p>We can make a difference. Planting and avoiding runoff are the most obvious solutions. Roots hold soil better than anything humans have invented. Usefully, they also direct water deep into the ground and remove carbon from the atmosphere.</p>
<p>The usual advice is to plant forests near the tops of catchments, where the ground is steepest and most vulnerable. Projects such as the government’s <a href="https://www.mpi.govt.nz/forestry/funding-tree-planting-research/one-billion-trees-programme/">One Billion Trees Programme</a> are promising, but the key is to leave those trees alone, or find ways to harvest them that minimise runoff.</p>
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Read more:
<a href="https://theconversation.com/new-zealands-maritime-territory-is-15-times-its-landmass-heres-why-we-need-a-ministry-for-the-ocean-210123">New Zealand's maritime territory is 15 times its landmass – here's why we need a ministry for the ocean</a>
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<p>The Building Research Association of New Zealand recommends <a href="https://www.level.org.nz/health-and-safety/airborne-and-other-pollutants/sediment-and-run-off/">managing construction projects to avoid runoff</a>, including using settling ponds and channels to retain dirty water, or chemical “<a href="https://enva.com/case-studies/flocculants-in-wastewater-treatment">flocculants</a>” to make fine sediments bind together into a glob and sink. Every project should include the post-completion planting needed to retain soil.</p>
<p>Individuals and households can plant gardens and trees to avoid bare spots. They can limit the use of concrete and other impervious surfaces or choose permeable concrete. They can capture rain from their roof in a rain barrel instead of using storm water drains.</p>
<p>The Māori concept of “<a href="https://niwa.co.nz/news/ki-uta-ki-tai-niwas-role-in-mountains-to-sea-estuarine-management">ki uta ki tai</a>” recognises the connection between the land and sea, and should inform more robust and holistic environmental management policy, from the mountaintops to the deep ocean. </p>
<p>Regional councils use these words, but we need to see real action. Working together, we can keep soil on land where it belongs, and the ocean clean and clear.</p><img src="https://counter.theconversation.com/content/221966/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abigail M Smith 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>Over 200 million tonnes of sediment are transported by rivers to the sea each year, the most widespread water contaminant in the country. Its devastating impact on marine life has to be reversed.Abigail M Smith, Professor of Marine Science, University of OtagoLicensed 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>
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<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>
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<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>
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<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/2174282023-12-14T22:14:08Z2023-12-14T22:14:08ZClimate change is further reducing fish stocks with worrisome implications for global food supplies<figure><img src="https://images.theconversation.com/files/565799/original/file-20231214-17-9k9tr0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4000%2C3000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Seafood is a ubiquitous human food-source, the future stability of which is uncertain.</span> <span class="attribution"><span class="source">(Pexels)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/climate-change-is-further-reducing-fish-stocks-with-worrisome-implications-for-global-food-supplies" width="100%" height="400"></iframe>
<p>The health benefits of eating seafood are appreciated in many <a href="https://www.fao.org/3/cc0461en/online/sofia/2022/consumption-of-aquatic-foods.html">cultures</a> which rely upon it to provide critical nutrients vital to our <a href="https://doi.org/10.1016/bs.afnr.2021.04.001">physical and mental development and health</a>. Eating fish and shellfish provides significant benefits to <a href="https://doi.org/10.1038/nrn3820">neurological development and functioning</a> and provides protection against the risks of <a href="https://doi.org/10.1038/s43016-019-0013-1">coronary heart disease and Type 2 diabetes</a>. </p>
<p>Over three billion people get at least 20 per cent of their daily animal protein from fish. In countries from Bangladesh to Cambodia, Gambia, Ghana, Indonesia, Sierra Leone and Sri Lanka, <a href="https://www.fao.org/3/ca9229en/ca9229en.pdf">fish consumption accounts for 50 per cent or more</a> of daily intake.</p>
<p>However, expansive growth of human populations globally puts immense pressure on the health of wild fish stocks. Fish catches <a href="https://doi.org/10.1038/ncomms10244">peaked in 1996</a>, and <a href="https://www.fao.org/state-of-fisheries-aquaculture">one-third are considered overexploited</a>. With less fish available to still more people, the future of fish as an accessible source of nutritious food is at risk, particularly among low-income countries.</p>
<h2>Seafood nutrient losses</h2>
<p>Threats to seafood access aren’t just due to overharvesting. There is a growing body of research showing that higher water temperatures due to climate change can impact the <a href="https://doi.org/10.1038/nature12156">presence and abundance of the catch</a>, through shifts in species distribution and changes in the species caught. This impacts the amount that can be harvested, as well as the nutritional value of that harvest.</p>
<p>A <a href="https://doi.org/10.1038/s41558-023-01822-1">new study</a> (which Aaron MacNeil contributed to) quantified nutrient availability from seafood through time considering the twin impacts of overfishing and climate change. </p>
<p>Focusing on four key nutrients important to human health — calcium, iron, omega-3 fatty acids and protein — the authors argue that nutrient availability in seafood has been declining since 1990 and will further decline by around 30 per cent by 2100 in predominately tropical, low-income countries with 4 C of warming.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/how-climate-change-induced-stress-is-altering-fish-hormones-with-huge-repercussions-for-reproduction-213140">How climate change-induced stress is altering fish hormones — with huge repercussions for reproduction</a>
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<p>These predicted losses are significant. While global famines are now relatively rare, some <a href="https://doi.org/10.1016/j.gfs.2020.100480">50 million people suffer from “hidden hunger”</a> — nutrient-deficient diets that are masked by being otherwise calorie-sufficient. </p>
<p>For animal-derived nutrients such as B12 and omega-3 fatty acids, <a href="https://doi.org/10.1038/534317a">nearly 20 per cent of the global population are at risk of becoming nutrient-deficient</a> in coming decades due to reliance on wild-caught fish.</p>
<p>Climate change is also affecting natural cycles of nutrients in the ocean. For example, it has been predicted that increasing water temperatures will cause a <a href="https://doi.org/10.1007/s13280-019-01234-6">decline in natural omega-3 availability from seafood by more than 50 per cent by 2100</a>. At the bottom of the food chain, microalgae that naturally produce omega-3s <a href="https://doi.org/10.1111/gcb.13295">are less productive at warmer temperatures</a> and this cascades through marine and freshwater food chains resulting in fish having less omega-3s available to eat and store in their bodies. </p>
<figure class="align-center ">
<img alt="Men standing on three small boats cast nets into the ocean." src="https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565818/original/file-20231214-15-s4v8j4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The global problems of climate change and overfishing have led to decreasing availability of seafood for millions around the world.</span>
<span class="attribution"><span class="source">(Pexels)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>These kinds of climate-caused losses are expected to disproportionately affect vulnerable populations, especially in inland Africa.</p>
<h2>Challenges and strategies for nutritious seafood</h2>
<p>Aquaculture can help supply some of these missing nutrients, but it is an industry also vulnerable to the effects of climate change. A <a href="https://doi.org/10.3389/fsufs.2021.609097">recent study</a> predicted that 90 per cent of aquaculture will be impacted by climate change, where warm waters increase <a href="https://www.jstor.org/stable/26920865">disease outbreaks, harmful algal blooms and impact the availability of feed supplies</a>.</p>
<p><a href="https://www.un.org/en/global-issues/food">Global disparities already exist in food security</a> that will be exacerbated by climate change in the future. Yet the effects of warming waters on nutrient availability from seafood will compound these inequities among tropical and low-income countries. </p>
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Read more:
<a href="https://theconversation.com/the-future-of-fishing-and-fish-and-the-health-of-the-ocean-hinges-on-economics-and-the-idea-of-infinity-fish-182749">The future of fishing and fish — and the health of the ocean — hinges on economics and the idea of 'infinity fish'</a>
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<p>These results suggest a major challenge to our future nutritional security that demands strong fisheries and aquaculture management to facilitate equitable distribution of nutritious seafoods. </p>
<p>Improvements are possible. </p>
<p>For example, <a href="https://doi.org/10.1038/s41586-019-1592-6">redirecting nine per cent of Namibia’s fisheries toward its coastal population</a> would alleviate the severe iron deficiencies experienced there. Policies that prioritize nutrient supply would help maintain diets as the climate warms. </p>
<p>The recent United Nations call to action for <a href="https://www.fao.org/documents/card/en?details=cc0459en/">blue transformation</a> emphasizes the need to provide sufficient aquatic food from fisheries and aquaculture for our growing population in a sustainable way. </p>
<p>To do this, strategies are needed to achieve healthy, equitable and resilient food systems that adequately deal with overfishing, strive for equal access to resources and markets and mitigate the environmental impacts of aquatic food production. </p>
<p>Ultimately, these strategies must support the nutritional security of vulnerable nations and consider global health equity and the cultural significance of seafood.</p><img src="https://counter.theconversation.com/content/217428/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stefanie Colombo receives funding from the Natural Sciences and Engineering Research Council and the Ocean Frontier Institute, through an award from the Canada First Research Excellence Fund. She serves as the Science Advisor for the Aquaculture Association of Nova Scotia. </span></em></p><p class="fine-print"><em><span>Aaron MacNeil receives funding from the Shark Conservation Fund, the Natural Sciences and Engineering Research Council, and the Ocean Frontier Institute, through an award from the Canada First Research Excellence Fund.</span></em></p>Climate change and overfishing are depleting global fish stocks with clear implications for the food security future of billions of people.Stefanie Colombo, Canada Research Chair in Aquaculture Nutrition, Dalhousie UniversityAaron MacNeil, Professor, Department of Biology, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170252023-11-13T21:44:00Z2023-11-13T21:44:00ZGulf of St. Lawrence: Analyzing fish blood can show us how healthy they are<figure><img src="https://images.theconversation.com/files/557461/original/file-20231003-21-bibw4p.jpeg?ixlib=rb-1.1.0&rect=30%2C12%2C3995%2C3005&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The industrialization of the fishing industry and changes in the environment have raised many issues about the management of our fisheries.</span> <span class="attribution"><span class="source">(Fanny Fronton)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>The Gulf of St. Lawrence is an invaluable resource for Canada. Fish and shellfish fisheries that date to the 16th century have remained an essential source of income for many communities, including those on the North Shore and Gaspésie or the Îles-de-la-Madeleine.</p>
<p>For example, in <a href="https://publications.gc.ca/collections/collection_2019/mpo-dfo/Fs124-10-2018-eng.pdf">Îles-de-la-Madeleine</a>, nearly 1,800 jobs (for a total of 12,500 inhabitants) were linked to fishing in 2015.</p>
<p>But the industrialization of fishing, and changes in the environment, have brought about many new problems in the management of our fisheries. The abundance of different fish species in the Gulf has fluctuated greatly over the last 20 years.</p>
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<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
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<p>A case in point: the number of Greenland halibut has declined drastically. This year, <a href="https://www.hi.no/hi/nettrapporter/imr-pinro-en-2023-6">landings</a> are six times lower for fishermen compared to last year.</p>
<p>But other species are benefiting from the situation. This is the case for the population of Atlantic halibut, which is at record levels today.</p>
<p>What is causing these changes? And can we predict further changes?</p>
<p>As a doctoral student in biology at the Institut national de la recherche scientifique (INRS), I am trying to find possible answers to these questions as part of my research work.</p>
<h2>A new health monitoring technique</h2>
<p>The means available for studying the health of fish at the individual level are limited. On the one hand, we can calculate indicators from the weight and height of individual fish. But these measurements are too vague and don’t tell us much.</p>
<p>The logistics of performing biopsies on the tissue of fish — which requires taking samples from their muscle or organs — are complex. To carry them out, researchers must have to travel to the ocean, physically collect samples and bring them back to a laboratory. And then there are ethical considerations, since obviously fish must be sacrificed to achieve this.</p>
<p>Even so, these methods are not very effective for detecting stress induced by environmental changes, and are not effective for detecting stress at early stages, before the physical effects can become manifest.</p>
<p>Yet in a context where the abundance of certain fish species is in rapid decline, an analysis of their overall health is necessary. Fortunately, a new tool is being developed: the <a href="https://www.nature.com/articles/s41598-023-32690-6">circulating microbiome</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="viruses in the blood" src="https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&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">It is often wrongly believed that blood is sterile.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>A little-known practice</h2>
<p>The circulating microbiome is a biomarker, an alarm signal that can be detected in fish even before their health begins to deteriorate. A good biomarker is sensitive, easy to sample, and inexpensive.</p>
<p>The analysis of the circulating microbiome, made up of the DNA of bacteria found in the blood, is directly inspired by <a href="https://theconversation.com/ladn-%20circulating-a-new-simple-and-rapid-weapon-in-the-diagnosis-and-monitoring-of-cancers-206786">similar analyses performed on humans</a>, which provide a great deal of information.</p>
<p>In particular, these analyses make it possible to detect anomalies resulting from the effect of a stress factor on the body, or the development of a disease.</p>
<p>Changes in the environment can also be detected from studying the circulating microbiome. But a major problem emerges here: a fish is not a human. Humans are studied in such detail that knowledge about their health can then be used for an infinite amount of further research. However, sampling fish blood is not a common practice. So there is a great deal that needs to be done before we can properly evaluate the health of fish.</p>
<p>Since the analysis of the circulating microbiome in fish has never been studied before, a lot of work needs to be done to develop the technique.</p>
<h2>Traces of bacteria in the blood?</h2>
<p>As blood circulates throughout the body, it comes into contact specifically with bacteria that make up the other microbiomes (intestinal, oral, dermal). Both in fish and humans, these bacteria are essential for good health.</p>
<p>When we analyze bacterial DNA in the blood, it is therefore possible to find bacteria from the intestine, mouth, or skin. But the hypothesis that these are bacteria specific to the blood cannot be completely ruled out either.</p>
<p>While some continue to believe that blood is sterile, and therefore does not contain any bacteria, we have known since the 1970s that this hypothesis is false — it was confirmed <a href="https://doi.org/10.1128/jcm.39.5.1956-1959.2001">in the 2000s by genomic studies</a>. It’s possible that in 1674, the Dutch microbiologist Antonie Van Leeuwenhoek may even have observed bacteria in salmon blood <a href="https://doi.org/10.3389/fcimb.2019.00148">under a microscope</a>.</p>
<p>Today, we can analyze these bacteria in detail by targeting a very specific bacterial gene, the 16S ribosomal RNA gene. Present in all bacteria around the world, this gene varies slightly from one species to another. That makes it possible to identify and analyze the biodiversity of the microbiome.</p>
<h2>I eat, therefore I am</h2>
<p>Our recent work has made it possible to characterize, for the first time, the <a href="https://www.nature.com/articles/s41598-023-32690-6">circulating microbiomes of turbot and halibut</a>. We have demonstrated that the two fish species have circulating microbiomes dominated by the presence of the species <em>Pseudoalteromonas</em> and <em>Psychrobacter</em>. These bacteria are known to colonize cold environments, for example the bottom of the Gulf of St. Lawrence, which is around 5°C. They are also known to produce bioactive compounds (antibacterials and antifungals). They are more tenacious than other bacteria.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="person with blue gloves holds a fish" src="https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Greenland halibut.</span>
<span class="attribution"><span class="source">(Fanny Fronton)</span>, <span class="license">Fourni par l'auteur</span></span>
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</figure>
<p>However, differences can be observed between the two species. Turbot has more bacteria called <em>Vibrio</em>, some of which metabolize chitin, a molecule that makes up the shells of the invertebrates on which it feeds. Atlantic halibut, for its part, presents more <em>Acinetobacter</em> bacteria, typical of piscivorous (fish-eating) diets in the intestinal microbiomes. The circulating microbiome in these two fish species therefore seems to be influenced by intestinal bacteria, as is the case in humans. We could therefore potentially link a blood microbiome to the fish’s diet, which is often difficult to estimate.</p>
<h2>An embryonic, but promising technique</h2>
<p>So this first bacterial mapping of the blood of these two species probably reflects their respective intestinal microbiome. From this characterization, detection of a variation in the composition of bacteria could be linked to stress, a change in the environment or a physiological change in the animal.</p>
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<a href="https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="comic strip" src="https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=907&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=907&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=907&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1140&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1140&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1140&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comic strip illustrating the principle of analyzing the circulating microbiome.</span>
<span class="attribution"><span class="source">(Fanny Fronton)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>For example, we know that in humans, the loss of <em>Actinobacteria</em> in the circulating microbiome is associated with severe acute <a href="https://doi.org/10.3389/fcimb.2018.00005">pancreatitis</a>. And there are dozens of examples like this in humans.</p>
<p>This study, the result of a collaboration between university researchers from INRS, the University of Québec at Rimouski and the Department of Fisheries and Oceans Canada, provides a small overview of the informative potential offered by the blood microbiomes of fish from the Gulf of St. Lawrence.</p>
<p>Further research will make it possible to estimate their health and better predict the evolution of their population. The dramatic collapse of the cod stock in the late 1980s had a major impact on fishermen. Several of them even fear that this situation will happen again with another species. As turbot remains a species at risk, it is essential to ensure better management of St. Lawrence species.</p>
<p>Only by refining our analysis techniques and deepening our scientific knowledge can we prevent this type of collapse from happening again in the future.</p><img src="https://counter.theconversation.com/content/217025/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fanny Fronton received a grant from the Fondation Armand Frappier.</span></em></p>Blood isn’t sterile, and analyzing the bacteria in it could help assess the health of fish and prevent the collapse of their populations.Fanny Fronton, Doctorante en Écologie halieutique et biologie moléculaire, Institut national de la recherche scientifique (INRS)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2164892023-10-31T16:47:07Z2023-10-31T16:47:07ZFarming tuna on land heralded as a win for sustainability – but there are serious concerns around animal welfare<figure><img src="https://images.theconversation.com/files/556597/original/file-20231030-21-lzpkx3.jpg?ixlib=rb-1.1.0&rect=7%2C0%2C5160%2C3998&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/tuna-caught-atlantic-blue-transit-box-1795226674">Steven4z/Shutterstock</a></span></figcaption></figure><p><a href="https://www.nationalgeographic.com/animals/fish/facts/atlantic-bluefin-tuna">Atlantic bluefin tuna</a> used to be caught only relatively rarely, mainly by sports fishermen in North America. But this all changed in the 1950s when consumers of sushi, particularly in Japan, <a href="https://www.google.com/books/edition/_/CE95Nn2N34sC?hl=en">developed more of a taste</a> for the species. </p>
<p>Historically, Atlantic bluefins have either been caught directly from the ocean or caught while young and fattened in large offshore cages called “ranches”. Both wild fishing and ranching pose sustainability issues since they involve taking fish from the wild. The surge in demand resulted in excessive fishing pressure. By 2006, the International Commission for the Conservation of Atlantic Tunas <a href="https://www.iccat.int/Documents/Recs/compendiopdf-e/2006-05-e.pdf">warned</a> that the Atlantic bluefin stock was close to collapse. </p>
<p>Scientists are now exploring ways to breed Atlantic bluefin tuna in captivity as an alternative to catching young fish from the sea. These approaches involve the manipulation and release of hormones into the water to stimulate egg production in the fish. The resulting eggs and fish larvae are then kept in a series of tanks until they grow to a suitable size, at which point they are relocated to cages at sea.</p>
<p>In a significant breakthrough in July 2023, scientists at the Spanish Institute of Oceanography <a href="https://www.theguardian.com/environment/2023/sep/04/breeding-breakthrough-paves-way-for-intensive-tuna-farming-on-land">successfully bred Atlantic bluefin tuna</a> in tanks on land for the first time. This development has been seen as a <a href="https://www.nexttuna.com/page7.html#:%7E:text=Next%20Tuna%20will%20provide%20the,for%20European%20and%20global%20consumers.">win for sustainability</a>. By breeding fish in enclosed tanks, fewer Atlantic bluefins will need to be caught from the wild.</p>
<p>But there are concerns surrounding the welfare of farmed tuna and their environmental impact. Atlantic bluefins are not well suited to captivity as ordinarily they <a href="https://www.mdpi.com/2071-1050/15/4/2976">migrate over thousands of miles</a> of open ocean. Research also suggests that the methods used to get the tuna to spawn may <a href="https://www.academia.edu/33670655/Van_Beijnen_2017_The_closed_cycle_aquaculture_of_Atlantic_Bluefin_Tuna_in_Europe_current_status_market_perceptions_and_future_perspectives">cause them stress</a>.</p>
<h2>Welfare in hatcheries</h2>
<p>An astonishing proportion of tuna larvae die in the hatcheries. In the EU’s early Atlantic bluefin domestication project, called Transdott, which started in 2012, <a href="https://cordis.europa.eu/project/id/311904/reporting">only 0.44% of tuna larvae</a> survived 30 days after hatching. </p>
<p>This death rate seems shockingly high. But an <a href="https://academic.oup.com/plankt/article/44/5/782/6307936">extremely high number</a> of tuna larvae die in the wild as well. Hatcheries may also become better at preventing some of these deaths in future, since they will struggle to make a profit if most of their stock dies. </p>
<p>There are, however, causes of death within hatcheries that don’t exist in the wild. Some larvae die by crashing into tank walls and others perish when they are moved between tanks. </p>
<p>It’s difficult to assess the day-to-day experience of tuna in hatcheries. Part of the reason for this is because conditions in hatcheries are often kept private. But undomesticated species of fish generally experience <a href="https://www.sciencedirect.com/science/article/abs/pii/S1050464821001182#:%7E:text=Generally%2C%20domesticated%20fish%20were%20characterized,comparison%20to%20the%20wild%20fish.">greater stress in captivity</a> and in response to human handling than domesticated species, which have adapted to this over time. </p>
<p>Since we are in the early stages of the domestication process for Atlantic bluefins, we should expect the tuna to be stressed by the large degree of human contact.</p>
<p>There is also some evidence that fish can become distressed by noise and are unaccustomed to vibrations. But noise may be hard to avoid on farms, particularly inland. <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.200172">One study</a> found that <a href="https://www.britannica.com/animal/guppy">guppies</a> exposed to chronic noise exhibited a significantly shorter lifespan compared with those in either acute noise or noise-free conditions.</p>
<p>On a more positive note, it’s in producers’ interests to ensure that their fish have good welfare and are not distressed. <a href="https://www.tandfonline.com/doi/abs/10.4081/ijas.2005.2s.603">Research</a> has found that stressed fish don’t taste as good, so they don’t fetch as high a price.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing each life stage of the Atlantic bluefin tuna." src="https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=341&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=341&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=341&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=428&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=428&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556603/original/file-20231030-23-q4pcps.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=428&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 life cycle of the Atlantic bluefin tuna.</span>
<span class="attribution"><a class="source" href="https://creativecommons.org/licenses/by-nc-nd/4.0/">The Spanish Institute of Oceanography</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>The transfer of young tuna to offshore enclosures raises several environmental concerns. Tuna are fed substantial amounts of frozen fish, such as mackerel and sardines, and there is always at least some uneaten. <a href="http://dx.doi.org/10.1111/j.1365-2109.2007.01649.x">Research</a> has shown that this residual feed, when combined with fish faeces, reduces biodiversity directly below the tuna cages.</p>
<p>Other species of fish that are kept in captivity, such as <a href="https://www.britannica.com/animal/Atlantic-salmon">Atlantic salmon</a>, often experience <a href="https://www.nhm.ac.uk/discover/the-problem-of-sea-lice-in-salmon-farms.html">high numbers of parasitic infestations</a> because they are packed so closely together. <a href="https://www.ncrac.org/files/biblio/SRAC0474.pdf">Research</a> suggests that higher stress levels can render fish more susceptible to diseases too. As tuna farming operations grow, there will probably be a need to use more antimicrobials to treat disease outbreaks.</p>
<h2>Slaughtering methods</h2>
<p>The <a href="https://www.sciencedirect.com/science/article/abs/pii/S0144860905000701">most common way</a> of slaughtering large Atlantic bluefins is to shoot the fish in the head while they are still underwater. This method should theoretically cause minimal suffering as the fish usually die instantly. However, it’s not yet clear how easy it is for farm workers to get this technique right.</p>
<p>Smaller tuna are slaughtered in a way that probably causes them more suffering. The fish are crowded before slaughter, sometimes for several hours, which causes distress. They are then hauled out of the water and stabbed in the head with a metal spike (a process called “coring”). Fish can be mis-cored, meaning that they don’t lose consciousness immediately.</p>
<p>The extent of welfare concerns in Atlantic bluefin tuna hatcheries remains uncertain. But it’s worth noting that many of the factors that are detrimental to fish welfare may also have negative consequences for companies in the industry. </p>
<p>High death rates can hinder profitability, while stressed fish may be less palatable and, as a consequence, less valuable. As the industry evolves, there may be inherent incentives for companies to improve the welfare conditions for farmed Atlantic bluefin tuna.</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>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<p class="fine-print"><em><span>Wasseem Emam has received funding from the Natural Sciences and Engineering Research Council of Canada.
Amber Dawn Ace and Valerie Monckton contributed to the drafting of this article.</span></em></p>Breeding tuna in captivity is a promising solution to overfishing, but there are concerns surrounding fish welfare.Wasseem Emam, PhD Candidate in the Institute of Aquaculture, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2098072023-07-31T11:44:09Z2023-07-31T11:44:09ZI’ve spent 50 years studying one seabird colony fight its way back from near extinction – now it faces new threats<figure><img src="https://images.theconversation.com/files/539505/original/file-20230726-27-rfmrqb.jpg?ixlib=rb-1.1.0&rect=31%2C0%2C3500%2C2321&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A guillemot nesting on a cliff ledge on Skomer Island, south Wales.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/guillemot-nesting-on-cliff-ledge-skomer-454070743">Andrew Astbury/Shutterstock</a></span></figcaption></figure><p>Over the past few decades, Skomer Island off the south coast of Wales has witnessed a remarkable resurgence in its guillemot population. Before 1930, Skomer was home to over 100,000 <a href="https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/guillemot/">common guillemots</a>. But by the end of the second world war, this number had <a href="https://www.researchgate.net/publication/320460192_Changes_in_the_numbers_of_common_guillemots_on_skomer_since_the_1930s">plummeted by about 95%</a> and continued to decline for the next few decades. </p>
<p>This population decline was probably caused by chronic oil pollution during the second world war and several major oil tanker incidents in the subsequent years. In 1967, for example, the supertanker SS Torrey Canyon <a href="https://www.bbc.co.uk/news/uk-england-39223308">spilled over 100,000 tonnes of crude oil</a> into the English channel.</p>
<p>However, counts conducted by the Wildlife Trust of South and West Wales show that Skomer’s guillemot population has consistently grown at an <a href="https://britishbirds.co.uk/content/june-2023">annual rate of about 5%</a> since the 1980s. In 1972, there were around 2,000 guillemots breeding on Skomer. Fast forward to 2023 and that number has skyrocketed to around 30,000. </p>
<p>This resurgence has been the subject of a long-term study conducted by myself and my colleagues over past 50 years. The increase in Skomer’s guillemot population is remarkable considering that populations in northern regions of the country have declined over the same period. </p>
<p>But our study also reveals that seabirds, including Skomer’s guillemots, now face several pressing threats – with climate change emerging as one of the most significant challenges.</p>
<figure class="align-center ">
<img alt="Tim Birkhead sat on top of a cliff peering through binoculars." src="https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539550/original/file-20230726-15479-ui884.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Tim Birkhead (pictured) has studied guillemots (Uria aalge) on Skomer Island for 50 years.</span>
<span class="attribution"><span class="source">K. Nigge</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Guillemots on the rise</h2>
<p>We have been monitoring the survival and breeding success of guillemots on Skomer. Our aim was to establish whether chick production, breeding age and adult and chick survival rates could explain the observed increase in their numbers. It took 30 years until we had a sufficient sample size to address these questions.</p>
<p><a href="https://www.researchgate.net/publication/260104714_The_population_increase_of_common_guillemots_Uria_aalge_on_Skomer_Island_is_explained_by_intrinsic_demographic_properties">Our results</a> showed that the population increase since 1980 is entirely due to the productivity and survival of the Skomer birds themselves. In fact, there’s relatively little immigration or emigration affecting the colony’s numbers. </p>
<p>There has, however, been a <a href="http://www.seabirdgroup.org.uk/journals/seabird-34/seabird-34-1.pdf">marked reduction in oil pollution</a> in waters surrounding the UK in recent years. In the 1970s, around 90% of the dead guillemots found on beaches surrounding the North Sea were contaminated with oil. By 2020, this proportion had fallen to 10%. </p>
<p>This decline in oil pollution may be what has allowed the guillemot population on Skomer and other southern regions of the UK to bounce back towards the levels seen before 1930.</p>
<h2>Breeding earlier</h2>
<p>However, seabirds, including Skomer’s guillemots, continue to face a <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129342">multitude of threats</a>. Oil pollution has declined, but it has been superseded by the even more insidious and <a href="https://www.cebc.cnrs.fr/wp-content/uploads/publipdf/2021/SS372_2021.pdf">far-reaching effects of climate change</a>. Together with <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.13442">persistent overfishing</a> and the recent <a href="http://www.seabirdgroup.org.uk/journals/seabird-34/seabird-34-C.pdf">emergence of avian flu</a>, climate change has further contributed to the increasing fragility of seabird populations.</p>
<p>One of our most striking results is that the timing of guillemot breeding has advanced by more than two weeks on average since the 1970s. The cause of this advance, which has also been noted in many bird species on land, is <a href="https://www.bto.org/sites/default/files/publications/bto_climate_change_and_uk_birds_-_james_pearce-higgins_bto_web-compressed.pdf">probably climate change</a>.</p>
<p>We believe the early breeding season might be linked to the seasonal availability of their fish prey. There is <a href="https://onlinelibrary.wiley.com/doi/10.1002/aqc.2244">increasing evidence</a> that warmer seas are having a marked effect on both the distribution and abundance of marine fish in the UK.</p>
<h2>Dealing with extreme weather</h2>
<p>Climate change is also causing an increase in the frequency and intensity of winter storms. Sustained bad winter weather makes it difficult for guillemots and <a href="https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/puffin/">puffins</a> (another member of the bird family known as auks) to find food. This can lead to devastating “wrecks” where large numbers of dead seabirds wash up on the shore.</p>
<p>In early 2014, a series of storms resulted in the <a href="http://www.seabirdgroup.org.uk/journals/seabird-29/seabird-29-22.pdf">deaths of over 55,000 seabirds</a> around European coastlines, including 15,000 guillemots. In that year, the mortality rate of Skomer’s adult guillemots doubled to 12%. </p>
<figure class="align-center ">
<img alt="Guillemots mating on Skomer island, UK." src="https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539497/original/file-20230726-15-kg6ywj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Extreme weather is becoming more common during the breeding season.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/guillemots-uria-aalge-mating-skomer-island-1055564837">Salparadis/Shutterstock</a></span>
</figcaption>
</figure>
<p>More worrying is the increasing incidence of extreme weather during the guillemots’ breeding season. Summers are witnessing stronger winds, rougher seas, torrential rain and extreme heat – all of which can reduce guillemot breeding success. </p>
<p>In May 2022, for example, two unseasonal storms resulted in many guillemots losing their eggs from breeding ledges, leading to the lowest breeding success we have seen on Skomer for several decades.</p>
<p>Long-term studies like mine provide the information that allows us to identify and measure the effects of different threats. In a few cases, they may also allow us to take action to minimise their effects. Yet these studies are few and far between.</p>
<p>As I see it, long-term studies on Skomer provide the ammunition that can help us fight the war against climate change and environmental degradation. Now more than ever, it is important that such studies continue.</p>
<hr>
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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><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/209807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Birkhead has in the past received funding from the Countryside Council for Wales (CCW), the University of Sheffield and the Natural Environment Research Council (NERC), but for the last ten years the project has been supported entirely by crowd funding</span></em></p>Studying a guillemot colony for 50 years has provided unique insights into how climate change and oil spills affect seabird populations.Tim Birkhead, Emeritus Professor of Zoology, University of SheffieldLicensed 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>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/XqZsoesa55w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<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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<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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<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>
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<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>
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<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>
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<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">
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<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>
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<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>
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<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>
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<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/2037392023-07-10T21:05:54Z2023-07-10T21:05:54ZClimate change is transforming our oceans. Can fisheries management adapt?<figure><img src="https://images.theconversation.com/files/523608/original/file-20230501-28-hwh67t.jpg?ixlib=rb-1.1.0&rect=251%2C305%2C5739%2C3682&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In the 1990s, the northern cod population in Newfoundland, Canada, collapsed by more than 99 per cent.</span> <span class="attribution"><span class="source">(Ricardo Resende/Unsplash)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/climate-change-is-transforming-our-oceans-can-fisheries-management-adapt" width="100%" height="400"></iframe>
<p>Newfoundland’s northern cod was once thought to be an inexhaustible resource. In fact, much of the province’s history and culture continues to be linked with this iconic species. But in the 1990s, the northern cod population here <a href="https://doi.org/10.1890/1051-0761(1997)007%5B0091:WDFSCT%5D2.0.CO;2">collapsed by more than 99 per cent</a> along with <a href="https://doi.org/10.1098/rsos.170215">other groundfish species</a>.</p>
<p>In addition to prolonged overfishing, this decline has been attributed to the <a href="https://doi.org/10.5194/essd-13-1807-2021">ecosystem’s decreased productivity during a 15-year-long cold period in the Canadian Atlantic</a>, resulting in <a href="https://doi.org/10.1016/j.fishres.2021.106180">less food availability for cod</a> and other groundfish. The northern cod collapse brought about a fishing moratorium in 1992, putting more than <a href="https://canadiangeographic.ca/articles/cod-moratorium-how-newfoundlands-cod-industry-disappeared-overnight/">30,000 Newfoundlanders out of work</a>. </p>
<p>In the following years, cod and other groundfish were much slower to recover than expected. Meanwhile, invertebrates such as <a href="https://doi.org/10.1007/s11160-014-9349-7">snow crab</a> and <a href="https://doi.org/10.2960/J.v27.a5">northern shrimp</a> boomed. The soaring snow crab and shrimp fisheries fetched as much as ten times the price of cod. </p>
<p>Managing fisheries in ecosystems that undergo dramatic shifts in species dominance can be challenging — they are a moving target. As we explore ways to sustainably manage the fisheries of these moving targets, we need to have a flexible and adaptable management system, especially in times of a <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">rapidly changing climate that is altering marine ecosystems globally</a>. </p>
<h2>Challenges for fisheries science and management</h2>
<p>The Newfoundland story highlights a challenge for fisheries science and management. <a href="https://www.dfo-mpo.gc.ca/fisheries-peches/commercial-commerciale/atl-arc/2023/snow-crab-crabe-neige-tac-2023-eng.html">Fisheries catch quotas set by Fisheries and Oceans Canada</a> relative to the baseline of the population of the specific fish species — also referred to as reference points. </p>
<p>Reference points serve as standards to assess the present condition of a fish stock in relation to a preferred (or undesired) state. They guide setting sustainable limits of fishing quotas.</p>
<p>Quotas are set to prevent overfishing. Typically, fisheries targets aim to keep population biomass — the overall population size — at about 50 per cent of the unfished population baseline. In general, a fish population is most productive when it is at this level. </p>
<figure class="align-center ">
<img alt="A lot of fish in in a fishing boat" src="https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523612/original/file-20230501-28-dnw6ms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Atlantic cod removed from fishing boats in Newfoundland.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dkeats/5645779248/in/album-72157626428355069/">(Derek Keats/flickr)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Within fisheries management agencies in Canada, there has been a move to implement <a href="https://www.dfo-mpo.gc.ca/reports-rapports/regs/sff-cpd/precaution-back-fiche-eng.htm">“limit reference points”</a>. </p>
<p>These limit reference points mark the fine line between cautious and critical levels. If the fish stock falls below the limit, there is risk of serious harm to a fished population. Limit reference points are typically set between 20 to 30 per cent of the unfished biomass baseline. </p>
<p>If biomass falls below the limit, it is prudent to close the fishery until it recovers — although, <a href="https://doi.org/10.1139/facets-2020-0006">in Canada, this decision is subject to ministerial discretion</a>. </p>
<p>However, setting these reference points can be challenging when ecosystems are highly dynamic over time, <a href="https://essd.copernicus.org/articles/13/1807/2021/essd-13-1807-2021-discussion.html">as seen in Newfoundland</a>. In a highly dynamic ecosystem, reference points based on outdated productivity regimes are ineffective.</p>
<p>Sometimes initial baselines of unfished biomass are no longer achievable under a new productivity pattern. Accounting for changes in productivity can help prevent fish stocks from collapsing.</p>
<h2>A cutting-edge solution</h2>
<p>The challenge of managing fisheries in highly dynamic ecosystems has a new solution — “dynamic reference points.” <a href="https://doi.org/10.1016/j.fishres.2018.11.028">Dynamic reference points consider changes in the ecosystem and fish population productivity</a> to inform sustainable fisheries targets and to set limits to avoid overfishing. </p>
<p>Dynamic reference points are a way to adapt fisheries management to environmental changes. For example, if a fish stock is less productive than it was historically and has a lower population size, dynamic reference points account for this change.</p>
<p>By accounting for the influence of the environment and other species on fish stocks, this approach provides a bridge between fisheries management of individual species and <a href="https://www.dfo-mpo.gc.ca/reports-rapports/regs/sff-cpd/ecosys-back-fiche-eng.htm">an ecosystem-based fisheries management</a>. </p>
<p>Traditional fisheries reference points assume the environment and ecosystem are stable. This might be reasonable in some cases, but as <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">climate change is shifting species ranges and causing greater changes in environmental conditions</a>, ensuring reference points reflect these changes is important to sustainably manage fisheries. </p>
<h2>Overcoming barriers</h2>
<p>The uptake of this cutting-edge approach for fisheries management practices is not without barriers. Based on <a href="https://doi.org/10.1139/facets-2022-0216">our global expert survey</a>, just published, only 10 per cent of reported fisheries used dynamic reference points.</p>
<p>Our study found that institutional inertia and uncertainty about whether changes in ecosystems or fish stock productivity are lasting or not are some of the main barriers to the implementation of these dynamic reference points.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bar graph of the barriers to sustainable fisheries tool" src="https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523610/original/file-20230501-28-jmw3na.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&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 main barriers to implementing dynamic reference points in fisheries management as identified by survey participants.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1139/facets-2022-0216">(Tyler Eddy)</a>, <span class="license">Author provided</span></span>
</figcaption>
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<p>Government institutions that manage fisheries can be slow to adopt new approaches. This may benefit fishing industries, as they know what to expect. However, as <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">climate change increasingly affects marine ecosystems and the fisheries they support</a>, dynamic reference points provide a solution to adapt to these changes. </p>
<p>Overcoming the barriers to implementation of dynamic reference points is key for fisheries management agencies to effectively respond to highly dynamic ecosystems. While uncertainty about if changes in ecosystems or fish populations are lasting might never be removed, implementing dynamic reference points may promote early detection of — and rapid response to — those changes. </p>
<p>Ultimately, this can help prevent devastating collapses in species such as the northern cod of Newfoundland.</p><img src="https://counter.theconversation.com/content/203739/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tyler Eddy receives funding from the Ocean Frontier Institute, Fisheries & Oceans Canada, and the Natural Sciences and Engineering Research Council of Canada. </span></em></p><p class="fine-print"><em><span>Andrea Bryndum-Buchholz receives funding from the Ocean Frontier Institute.</span></em></p>Having a flexible and adaptable management system is necessary to sustainably manage fisheries, especially in times of a rapidly changing climate.Tyler Eddy, Research Scientist in Fisheries Science, Memorial University of NewfoundlandAndrea Bryndum-Buchholz, Postdoctoral Researcher in Marine Ecology and Climate-Impact Sciences, Memorial University of NewfoundlandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2070832023-06-06T12:29:31Z2023-06-06T12:29:31ZProtecting the ocean: 5 essential reads on invasive species, overfishing and other threats to sea life<figure><img src="https://images.theconversation.com/files/530186/original/file-20230605-15-w5h9js.jpg?ixlib=rb-1.1.0&rect=23%2C15%2C5283%2C3516&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fish in a kelp forest off San Benito Island, Mexico.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/garibaldi-fish-in-kelp-forest-hypsypops-rubicundus-san-news-photo/551022897">Photo by Reinhard Dirscherl/ullstein bild via Getty Images</a></span></figcaption></figure><p>Humans rely on the ocean for many things, including food, jobs, recreation and <a href="https://oceanexplorer.noaa.gov/facts/climate.html">stabilization of Earth’s climate</a>. But although ocean resources may seem infinite, human impacts like pollution, overfishing and climate change are creating what United Nations Secretary-General António Guterres has called an “<a href="https://press.un.org/en/2022/sea2143.doc.htm">ocean emergency</a>.” Climate change is pushing ocean temperatures to <a href="https://phys.org/news/2023-05-sea-surface-surge.html">record levels</a>, many <a href="https://www.fao.org/documents/card/en/c/cc0461en">fisheries are overharvested</a>, and plastic waste is <a href="https://www.nytimes.com/2022/04/03/science/ocean-plastic-animals.html">accumulating in the deep sea</a>.</p>
<p>These five articles from The Conversation’s archive spotlight urgent challenges for ocean conservation, and describe what researchers are doing to devise effective responses.</p>
<h2>1. A devastating invasion is expanding</h2>
<p>Invasive lionfish are aggressive predators, native to the Indo-Pacific Ocean, that feed on smaller reef fish. They have caused heavy damage in the Caribbean and Gulf of Mexico since they first appeared in the Atlantic in 1985. Now, they’ve spread south to Brazil, which has many rare endemic fish species and is behind the curve in responding. </p>
<p>“As one of many Brazilian scientists who warned repeatedly about a potential lionfish invasion over the past decade, I’m disheartened that my country missed the window to take early action,” wrote Charles Darwin University marine scientist <a href="https://scholar.google.com.au/citations?user=_ArEYYMAAAAJ&hl=en">Osmar J. Luiz</a>. “Now, however, marine researchers and local communities are stepping up.”</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A red-and-white striped fish with long spines in closeup." src="https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/530188/original/file-20230605-19-vvnm8h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Lionfish have venomous spines that protect them against predators.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/u8LkfH">Florida Fish and Wildlife</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>One important control strategy was to create an interactive dashboard where anyone can report lionfish sightings. Other steps are likely to include environmental education, organized culls and genetic research to identify distinct lionfish populations and see where they’re moving. With a similar lionfish invasion underway in the Mediterranean, there’s urgent need for effective responses.</p>
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<em>
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Read more:
<a href="https://theconversation.com/invasive-lionfish-have-spread-south-from-the-caribbean-to-brazil-threatening-ecosystems-and-livelihoods-199229">Invasive lionfish have spread south from the Caribbean to Brazil, threatening ecosystems and livelihoods</a>
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<h2>2. Mining the seabed poses ecological risks</h2>
<p>One of the ocean’s potentially most valuable resources hasn’t been tapped yet – but that could be about to change. </p>
<p>Scattered across large zones of the ocean floor, manganese nodules – lumps that look like cobblestones – contain rich deposits of <a href="https://theconversation.com/deep-seabed-mining-plans-pit-renewable-energy-demand-against-ocean-life-in-a-largely-unexplored-frontier-193273">nickel, copper, cobalt and other metals</a> that are newly in demand for manufacturing batteries and renewable energy components. </p>
<p>“A fierce debate is now playing out as a Canadian company makes plans to launch the first commercial deep sea mining operation in the Pacific Ocean,” Indiana University scholars <a href="https://scholar.google.com/citations?user=YtgRGx0AAAAJ&hl=en">Scott Shackelford</a>, <a href="https://law.indiana.libguides.com/ochoa">Christiana Ochoa</a>, <a href="https://scholar.google.com/citations?user=2bs3bogAAAAJ&hl=en">David Bosco</a> and <a href="https://www.researchgate.net/profile/Kerry-Krutilla">Kerry Krutilla</a> warned.</p>
<p>Less than 10% of the deep seabed has been mapped thoroughly, and most life forms discovered there have never been seen before. Collecting materials from the ocean floor could harm these species – for example, by burying them in sediments. “We believe it would be wise to better understand this existing, fragile ecosystem better before rushing to mine it,” the authors concluded.</p>
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Read more:
<a href="https://theconversation.com/deep-seabed-mining-plans-pit-renewable-energy-demand-against-ocean-life-in-a-largely-unexplored-frontier-193273">Deep seabed mining plans pit renewable energy demand against ocean life in a largely unexplored frontier</a>
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<h2>3. Illegal fishing is common and hard to detect</h2>
<p>Illegal fishing – taking too many fish, or harvesting threatened species – causes economic losses estimated at US$10 billion to $25 billion annually. It also has been linked to human rights violations, such as forced labor and human trafficking. But it’s easy to conduct these activities out of sight on the high seas.</p>
<p>By looking at when and where fishing boats turned off their location transponders at sea, academic and nongovernment researchers showed that these silences can be an important signal. </p>
<p>“Vessels frequently went dark on the high-seas edge of exclusive economic zone boundaries, which can <a href="https://theconversation.com/when-fishing-boats-go-dark-at-sea-theyre-often-committing-crimes-we-mapped-where-it-happens-196694">obscure illegal fishing in unauthorized locations</a>,” wrote <a href="https://scholar.google.com/citations?user=L0Ue4hIAAAAJ&hl=en">Heather Welch</a>, a researcher in ecosystem dynamics at the University of California, Santa Cruz. </p>
<p>Ships may also disable their transponders to avoid pirates or avoid drawing competitors to rich fishing sites, so making it illegal to turn their signals off isn’t a practical strategy. But more analysis of where boats go dark could help governments target inspections and patrols, reducing crimes at sea.</p>
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Read more:
<a href="https://theconversation.com/when-fishing-boats-go-dark-at-sea-theyre-often-committing-crimes-we-mapped-where-it-happens-196694">When fishing boats go dark at sea, they're often committing crimes – we mapped where it happens</a>
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<a href="https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Dozens of dead red snapper arranged in rows on a pier." src="https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/530190/original/file-20230605-15-2du56b.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>
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<span class="caption">Red snapper seized by Coast Guard law enforcement crews that interdicted a Mexican boat crew fishing illegally in federal waters off southern Texas, Nov. 24, 2017.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/ZwEV3B">U.S. Coast Guard</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<h2>4. Scientists are designing an ‘internet of the ocean’</h2>
<p>Just as there are unnumbered life forms in the ocean yet to be discovered, there also are many unanswered questions about its physical processes. For example, scientists know that the ocean <a href="https://www.pmel.noaa.gov/co2/story/Ocean+Carbon+Storage">pulls carbon from the atmosphere</a> and transfers it to deep waters, where it can remain stored for long periods. But they don’t know how biological and chemical shifts affect this carbon cycling process. </p>
<p>Scientists at the <a href="https://www.whoi.edu/">Woods Hole Oceanographic Institution</a> in Massachusetts are designing a monitoring system called the Ocean Vital Signs Network that could make it possible to test strategies for storing more carbon in the ocean and tracking how well they work. They envision “a large network of moorings and sensors that <a href="https://theconversation.com/scientists-envision-an-internet-of-the-ocean-with-sensors-and-autonomous-vehicles-that-can-explore-the-deep-sea-and-monitor-its-vital-signs-197134">provides 4D eyes on the oceans</a> – the fourth dimension being time – that are always on, always connected to monitor these carbon cycling processes and ocean health,” wrote WHOI director <a href="https://scholar.google.com/citations?user=Etpzd_UAAAAJ&hl=en">Peter de Menocal</a>, a marine geologist and paleoclimatologist.</p>
<p>The network would include intelligent gliders and autonomous vehicles that could collect data and then dock, repower and upload it. It also would use sensors and acoustic transceivers to monitor dark, hidden reaches of the ocean where carbon is stored. “This network makes observation possible for making decisions that will affect future generations,” de Menocal wrote.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/scientists-envision-an-internet-of-the-ocean-with-sensors-and-autonomous-vehicles-that-can-explore-the-deep-sea-and-monitor-its-vital-signs-197134">Scientists envision an 'internet of the ocean,' with sensors and autonomous vehicles that can explore the deep sea and monitor its vital signs</a>
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<h2>5. Ocean plastic waste has a message for humans</h2>
<p>Over the past several decades, plastic pollution has become one of the world’s more widespread environmental crises. Every year, millions of tons of plastic trash end up in the ocean, <a href="https://theconversation.com/newly-hatched-florida-sea-turtles-are-consuming-dangerous-quantities-of-floating-plastic-143785">killing sea creatures</a>, <a href="https://www.epa.gov/sciencematters/tiny-plastics-big-threat-how-are-microplastics-impacting-our-coral-reefs">smothering ecosystems</a> and <a href="https://theconversation.com/hundreds-of-fish-species-including-many-that-humans-eat-are-consuming-plastic-154634">threatening human health</a>.</p>
<p>Georgia State University art professor <a href="https://artdesign.gsu.edu/profile/pamela-longobardi/">Pam Longobardi</a> grew up in New Jersey, where her father brought home plastic trinkets from his job at the chemical company Union Carbide. Today, Longobardi collects plastic waste from shorelines around the world and sculpts it into large-scale installations that are both eye-catching and alarming. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large sculpted anchor in the center of an art gallery, with ties to life preservers mounted on the ceiling." src="https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/509544/original/file-20230210-25-ixc2yr.png?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">‘Albatross’ and ‘Hope Floats,’ 2017. Recovered ocean plastic, survival rescue blankets, life vest straps and steel.</span>
<span class="attribution"><span class="source">Pam Longobardi</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>“I see plastic as <a href="https://theconversation.com/my-art-uses-plastic-recovered-from-beaches-around-the-world-to-understand-how-our-consumer-society-is-transforming-the-ocean-187970">a zombie material that haunts the ocean</a>,” Longobardi wrote. “I am interested in ocean plastic in particular because of what it reveals about us as humans in a global culture, and about the ocean as a cultural space and a giant dynamic engine of life and change. Because ocean plastic visibly shows nature’s attempts to reabsorb and regurgitate it, it has profound stories to tell.”</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/my-art-uses-plastic-recovered-from-beaches-around-the-world-to-understand-how-our-consumer-society-is-transforming-the-ocean-187970">My art uses plastic recovered from beaches around the world to understand how our consumer society is transforming the ocean</a>
</strong>
</em>
</p>
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<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/207083/count.gif" alt="The Conversation" width="1" height="1" />
Humans rely on the ocean for food, jobs and other resources, but these systems are being stressed to the brink.Jennifer Weeks, Senior Environment + Cities Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2041952023-05-01T20:00:55Z2023-05-01T20:00:55ZWild-caught seafood is often untraceable – and some industry players don’t want that to change. Here’s why<figure><img src="https://images.theconversation.com/files/523567/original/file-20230501-26-l8bw6m.jpg?ixlib=rb-1.1.0&rect=74%2C37%2C6155%2C3465&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>The wild-caught fish you buy was landed far away from cameras or scrutiny. So how do you know it really is what the label says? How do you know it was caught in a sustainable fishery? Even in regulated fisheries like Australia’s, the answer is, broadly, you don’t. </p>
<p>That’s because most wild-caught seafood is untraceable. Yes, it could have been caught sustainably by pole and line fishers. But it could have been relabelled as a different fish altogether. Worldwide, seafood fraud <a href="https://www.theguardian.com/environment/2021/mar/15/revealed-seafood-happening-on-a-vast-global-scale">is rampant</a>. That’s why conservationists ask fish buyers to use apps like <a href="https://goodfish.org.au">GoodFish</a> to check. </p>
<p>And while technologies now exist to solve this problem and make opaque supply chains transparent, our <a href="https://www.sciencedirect.com/science/article/pii/S0160791X23000404?dgcid=author">new research</a> suggests many players in the Australian industry are not interested in change – particularly large wholesalers, processors and fish markets. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="prawn dinner" src="https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523565/original/file-20230501-26-8b9nej.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">Where did the prawns on your plate come from - and how do you know?</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What did we find?</h2>
<p>We interviewed people who work in seafood supply chains in Australia – from fishers and aquaculture companies to seafood traders and restaurants. </p>
<p>These insiders believed bigger supply chain actors were often not doing the right thing, by concealing trade information, manipulating prices, and with little concern about product origin. </p>
<p>Fishers and fish farmers explained that once their catch departs for the big seafood markets, they “lose control of the supply chain”, have “no idea where they go”, and that it’s “impossible to keep track of any of it”. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/where-is-your-seafood-really-from-were-using-chemical-fingerprinting-to-fight-seafood-fraud-and-illegal-fishing-189471">Where is your seafood really from? We’re using 'chemical fingerprinting' to fight seafood fraud and illegal fishing</a>
</strong>
</em>
</p>
<hr>
<p>Our interviewees told us a degree of <a href="https://link.springer.com/article/10.1007/s12571-018-0826-z">food fraud</a> still exists. This is when a species is incorrectly labelled by name, origin or how it was caught. </p>
<p>This can be accidental, or done deliberately to mask certain information or to justify selling it at a higher price. For example, <a href="https://www.marineconservation.org.au/commercially-fished-shark-species-declared-critically-endangered/">critically endangered</a> species such as the school shark are being <a href="https://www.sciencedirect.com/science/article/pii/S0956713523000063?via%3Dihub">mislabelled as gummy shark</a> – which is sustainably caught in Australia.</p>
<p>Chefs told us about regularly seeing species labelled as locally caught when they knew they were out of season in their state. </p>
<p>Fish farmers told us cheap overseas fish of questionable quality would often be sold as their fish. As one barramundi farm representative told us: </p>
<blockquote>
<p>It honestly really frustrates and upsets me because you do all this work and your barramundi is happily substituted.</p>
</blockquote>
<p>Fishers, fish farmers, and restaurants were largely supportive of traceability technologies. But they feared a backlash from the wholesalers on which their sales relied. Some interviewees reported experiences of threatening, bullying and cajoling from some wholesalers. </p>
<p>As one interviewee told us: </p>
<blockquote>
<p>I know that these guys [wholesalers], right or wrong, can hold me to ransom. If they don’t buy my fish, we don’t have ability to send [high volumes] to anyone else.</p>
</blockquote>
<h2>How would traceability improve the situation?</h2>
<p>At present, tracking where fish, prawns, shellfish and other seafood come from relies on largely paper-based systems. These are prone to human error, negligence, or manipulation. </p>
<p>In an effort to fix the problem, several traceability platforms have been developed in Australia. These tend to rely on blockchain, where encrypted “blocks” of product, trade, and price data are stored along a digital “chain” which is publicly visible. </p>
<p>This data is linked to a QR code on individual fish or boxes of fish. Data added include the species name, time of catch, product weight, and the time of each physical handover point – with new data being verified against preexisting data in the chain. Traders and consumers can scan these QR codes to access information on the seafood product in front of them.</p>
<p>In short, digital tracing of seafood would create a transparent trading environment by making public how the market operates, from buyers and sellers to the prices paid, and the ability to track seafood from ocean to plate. </p>
<p>A system like this would also give fishers more power. At present, wholesalers are often able to name a price that fishers simply have to accept. </p>
<p>Fishers would much prefer to be able to set their own prices. Traceability technology could help here too, to give fishers a sense of which seafood products are in demand right now and allow them to price their products accordingly. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="seafood tracing" src="https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=320&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=320&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=320&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=402&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=402&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523568/original/file-20230501-24-sn9s3b.jpeg?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">What if seafood was trackable from ocean to plate?</span>
<span class="attribution"><span class="source">Sascha Rust</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Australia should embrace greater seafood transparency</h2>
<p>Estimates of food fraud in global fisheries range widely, from <a href="https://www.fao.org/3/I8791EN/i8791en.pdf">20% up to 90%</a>. That is to say, we know there’s a real problem here – we just don’t know exactly how large. But we do know there are very real problems in the world’s wild-caught fisheries. </p>
<p>Australia could have a role here to demonstrate what good fisheries can look like. At present, our fishing authorities are primarily concerned with catch regulations at sea. </p>
<p>There’s not enough focus on what happens next. Our label-based traceability systems are <a href="https://cdn.minderoo.org/content/uploads/2021/09/29112031/20210917-mending-the-net.pdf">weak compared to the European Union</a> which has the strict import laws and seafood labelling standards that conservationists in Australia are <a href="https://www.faircatchalliance.org.au/">pushing for</a>.</p>
<p>But digital technology could offer something even better. While the EU’s solution is positive, it’s been <a href="https://www.sciencedirect.com/science/article/pii/S0308597X21002773">criticised</a> by scholars for being overly bureaucratic and not delivering the same depth of information.</p>
<p>Could it happen? Yes – but it would have to happen over the protests of those who would be disadvantaged, such as some seafood wholesalers. </p>
<p>One way it could happen is if the government adds more information disclosure requirements to laws governing fair competition. This would give the market the nudge required to see traceability technologies more rapidly adopted. </p>
<p>If nothing is done, Australia’s seafood industry could become less viable since illegal fishing practices would remain difficult to identify, putting strain on fish stocks. But we are optimistic that innovators will eventually succeed in bringing together enough actors across the supply chain to make the shift to digital traceability happen.</p>
<p>While many <a href="https://www.sciencedirect.com/science/article/pii/S0925527319300507#bib55">academics</a>, <a href="https://www.forbes.com/sites/bernardmarr/2018/03/23/how-blockchain-will-transform-the-supply-chain-and-logistics-industry/?sh=744b32005fec">disruptors</a> and <a href="https://www2.deloitte.com/us/en/pages/operations/articles/blockchain-supply-chain-innovation.html">commentators</a> often laud blockchain as a way to rapidly drive sustainable change, our research suggests this will only occur if the most influential supply chain actors see value in using it.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/blockchains-can-trace-foods-from-farm-to-plate-but-the-industry-is-still-behind-the-curve-138666">Blockchains can trace foods from farm to plate, but the industry is still behind the curve</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/204195/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This article is based on research co-authored with my industry partner Sascha Rust, who currently works for a digital technology developer operating in the Australian seafood industry. I undertook the data collection, interviews and analysis independently. </span></em></p>When you buy seafood, you can’t be sure it is what it says it is – and Australian wholesalers are resistant to new traceability technologies.Benjamin Thompson, Lecturer in Human Geography, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2002142023-04-04T12:16:46Z2023-04-04T12:16:46ZHow much is the world’s most productive river worth? Here’s how experts estimate the value of nature<figure><img src="https://images.theconversation.com/files/519125/original/file-20230403-22-i7bnbw.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5520%2C3668&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Establishing the financial worth of a river's fish is complicated when many people don't sell the fish they catch.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/this-photo-taken-on-january-5-2018-shows-women-removing-news-photo/902376180">Tang Chhin Sothy/AFP via Getty Images</a></span></figcaption></figure><p>Southeast Asia’s Mekong may be the most important river in the world. Known as the “mother of waters,” it is home to the world’s largest inland fishery, and the huge amounts of sediments it transports feed some of the planet’s most fertile farmlands. Tens of millions of people depend on it for their livelihoods.</p>
<p>But how valuable is it in monetary terms? Is it possible to put a dollar value on the multitude of ecosystem services it provides, to help keep those services healthy into the future?</p>
<p>That’s what my research colleagues and I are <a href="https://2012-2017.usaid.gov/cambodia/fact-sheets/wonders-mekong">trying to figure out</a>, <a href="https://2012-2017.usaid.gov/cambodia/fact-sheets/wonders-mekong">focusing on</a> two countries that hold <a href="https://wwfasia.awsassets.panda.org/downloads/key_findings_mekong_river_in_the_economy.pdf">the river’s most productive areas</a> for fishing and farming: Cambodia and Vietnam.</p>
<p>Understanding the value of a river is essential for good management and decision-making, such as where to develop infrastructure and where to protect nature. This is particularly <a href="https://e360.yale.edu/features/mekong-river-cambodia-recovery">true of the Mekong</a>, which has <a href="https://www.lowyinstitute.org/the-interpreter/trouble-mekong">come under enormous pressure</a> in recent years from overfishing, dam building and climate change, and where decisions about development projects often do not take environmental costs into account.</p>
<figure class="align-center ">
<img alt="A brown river winds through a steep cliffs with a road and some buildings along the banks." src="https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519126/original/file-20230403-28-5xowi1.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">The Mekong River winds through six countries, across 2,700 miles (about 4,350 kilometers) from the mountains to the sea.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/downstream-from-the-controversial-gongguoqiao-dam-on-the-news-photo/479183194">Leisa Tyler/LightRocket via Getty Images</a></span>
</figcaption>
</figure>
<p>“Rivers such as the Mekong function as life-support systems for entire regions,” said Rafael Schmitt, lead scientist at the Natural Capital Project at Stanford University, who has studied the Mekong system for many years. “Understanding their values, in monetary terms, can be critical to fairly judge the impacts that infrastructure development will have on these functions.”</p>
<p>Calculating that value isn’t simple, though. Most of the natural benefits that a river brings are, naturally, under water, and thus hidden from direct observation. Ecosystem services may be hard to track because rivers often flow over large distances and sometimes across national borders.</p>
<h2>Enter natural capital accounting</h2>
<p>The <a href="https://www.cbd.int/business/projects/natcap.shtml">theory of natural capital</a> suggests that ecosystem services provided by nature – such as water filtration, flood control and raw materials – <a href="https://doi.org/10.1126/science.289.5478.395">have economic value</a> that should be taken into account when making decisions that affect these systems.</p>
<p>Some people <a href="https://www.theguardian.com/commentisfree/2018/may/15/price-natural-world-destruction-natural-capital">argue that it’s morally wrong</a> to put a financial price on nature, and that doing so undermines people’s intrinsic motivation to value and protect nature. Critics say valuations <a href="https://neweconomics.org/2020/01/can-a-natural-capital-approach-restore-nature-in-the-uk">often do not capture</a> the <a href="https://sustainabledevelopment.un.org/content/documents/6569122-Pelenc-Weak%20Sustainability%20versus%20Strong%20Sustainability.pdf">whole worth of a natural service</a>.</p>
<p>Proponents maintain that natural capital accounting puts a spotlight on <a href="https://theconversation.com/putting-a-dollar-value-on-nature-will-give-governments-and-businesses-more-reasons-to-protect-it-153968">natural systems’ value</a> when weighed against commercial pressures. They say it brings visibility to natural benefits that are <a href="https://www.greenbiz.com/article/case-natural-capital-accounting">otherwise hidden</a>, using language that policymakers can better understand and utilize. </p>
<figure class="align-center ">
<img alt="Two people in a motor boat move through a section of lake with trees and small islands of vegetation." src="https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519127/original/file-20230403-18-8kpwds.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">More than a million people live on or around Tonle Sap lake, the world’s largest inland fishery. Climate change and dams can affect its water level and fish stocks.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/this-photo-taken-on-october-13-2020-shows-a-boat-driving-news-photo/1230240288">Tang Chhin Sothy/AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>Several countries have incorporated natural capital accounting <a href="https://doi.org/10.1016/j.ecoser.2017.09.008">in recent years</a>, including <a href="https://www.wavespartnership.org/en/knowledge-center/natural-capital-accounting-and-policy-costa-rica">Costa Rica</a>, <a href="https://www23.statcan.gc.ca/imdb/p2SV.pl?Function=getSurvey&SDDS=5114">Canada</a> and Botswana. Often, that has <a href="https://www.washingtonpost.com/climate-solutions/interactive/2021/gretchen-daily-natural-capital-environment/">led to better protection</a> of natural resources, such as mangrove forests that protect fragile coastlines. The U.S. government also <a href="https://www.whitehouse.gov/ostp/news-updates/2023/01/19/fact-sheet-biden-harris-administration-releases-national-strategy-to-put-nature-on-the-nations-balance-sheet/">announced a strategy</a> in 2023 to start developing metrics to account for the value of underlying natural assets, such as critical minerals, forests and rivers.</p>
<p>However, <a href="https://seea.un.org/news/new-business-and-natural-capital-accounting-case-studies-released">natural capital studies</a> have largely focused on terrestrial ecosystems, where the trade-offs between human interventions and conservation are easier to see. </p>
<p>When valuing rivers, the challenges run much deeper. “If you cut down a forest, the impact is directly visible,” Schmitt points out. “A river might look pristine, but its functioning may be profoundly altered by a faraway dam.”</p>
<h2>Accounting for hydropower</h2>
<p>Hydropower provides one example of the challenges in making decisions about a river without understanding its full value. It’s often much easier to <a href="https://www.omnicalculator.com/ecology/hydroelectric-power">calculate the value of a hydropower dam</a> than the value of the river’s fish, or sediment that eventually becomes fertile farmland.</p>
<p>The rivers of the Mekong Basin have been widely exploited for power production in recent decades, with a proliferation of dams in China, Laos and elsewhere. The <a href="https://monitor.mekongwater.org/virtual-gauges/?v=1642195188734">Mekong Dam Monitor</a>, run by the nonprofit <a href="https://www.stimson.org/project/mekong-dam-monitor/">Stimson Center</a>, monitors dams and their environmental impacts in the Mekong Basin in near-real time.</p>
<figure class="align-right ">
<img alt="Map showing the river through Vietnam and Cambodia" src="https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=718&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=718&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=718&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=902&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=902&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518678/original/file-20230331-26-r2tgxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=902&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The lower Mekong River.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/media/images/lower-mekong-river-basin-0">USGS</a></span>
</figcaption>
</figure>
<p>While hydropower is <a href="https://www.energy.gov/eere/water/benefits-hydropower">clearly an economic benefit</a> – powering homes and businesses, and contributing to a country’s GDP – dams also <a href="https://www.nationalgeographic.com/environment/article/is-building-more-dams-the-way-to-save-rivers">alter river flows</a> and block both fish migration and sediment delivery.</p>
<p>Droughts in the Mekong in recent years, <a href="https://asmc.asean.org/asmc-el-nino/">linked to El Niño</a> and exacerbated by climate change, were made worse by dam operators holding back water. That caused water levels to drop to historical low levels, with devastating consequences for fisheries. In the Tonlé Sap Lake, Southeast Asia’s largest lake and the heart of the Mekong fishery, thousands of fishers were <a href="https://www.voacambodia.com/a/fishers-leave-crisis-hit-tonle-sap-lake-in-search-of-livelihoods-ashore/6695988.html">forced to abandon their occupation</a>, and many <a href="https://www.nationalgeographic.com/animals/article/mekong-river-fish-migrations">commercial fisheries</a> had to close.</p>
<figure>
<iframe frameborder="0" class="juxtapose" width="100%" height="400" src="https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=7b7e5f2e-cf6e-11ed-b5bd-6595d9b17862"></iframe>
</figure><figure><figcaption>Hydropower dams like the one in the photos above in Cambodia can disrupt a river’s natural services. The Sesan River (Tonlé San) and Srepok River are tributaries of the Mekong. Move the slider to see how the dam changed the water flow. <a href="https://earthobservatory.nasa.gov/images/91761/a-new-reservoir-in-cambodia">NASA Earth Observatory</a></figcaption></figure>
<p>One project under scrutiny now in the Mekong Basin is a small dam being constructed on the Sekong River, a tributary, in Laos near the Cambodian border. While the dam is expected to generate a very small amount of electricity, <a href="https://www.iucn.org/news/viet-nam/202205/sekong-a-dam-lao-pdr-and-mekong-delta-a-moment-decision-viet-nam">preliminary studies show</a> it will have a dramatically negative impact on many migratory fish populations in the Sekong, which remains the last major free-flowing tributary in the Mekong River Basin.</p>
<h2>Valuing the ‘lifeblood of the region’</h2>
<p>The Mekong River originates in the Tibetan highlands and runs for 2,700 miles (about 4,350 kilometers) through six countries before emptying into the South China Sea.</p>
<p>Its <a href="https://2012-2017.usaid.gov/cambodia/fact-sheets/wonders-mekong">ecological and biological riches</a> are clearly considerable. The river system is home to over 1,000 species of fish, and the annual fish catch in just the lower basin, below China, is estimated at more than <a href="https://www.mrcmekong.org/our-work/topics/fisheries/">2 million metric tons</a>. </p>
<p>“The river has been the lifeblood of the region for centuries,” says Zeb Hogan, a biologist at the University of Nevada, Reno, who leads the USAID-funded <a href="https://2012-2017.usaid.gov/cambodia/fact-sheets/wonders-mekong">Wonders of the Mekong</a> research project, which I work on. “It is the ultimate renewable resource – if it is allowed to function properly.”</p>
<p>Establishing the financial worth of fish is more complicated than it appears, though. Many people in the Mekong region are <a href="https://www.theforgottenintl.org/in-the-world-today/subsistence-fishing/">subsistence fishers</a> for whom fish have little to no market value but are crucial to their survival.</p>
<figure class="align-center ">
<img alt="Two women row a small boat in through a narrow channel in the Mekong Delta. Another boat is passing them." src="https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519129/original/file-20230403-14-qk2mdy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Mekong Delta in Vietnam is essential to transportation, food and culture.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/woman-on-a-rowing-boat-on-mekong-river-near-my-tho-village-news-photo/849862626">Sergi Reboredo/VW PICS/Universal Images Group via Getty Images</a></span>
</figcaption>
</figure>
<p>The river is also home to some of the largest freshwater fish in the world, like <a href="https://doi.org/10.1126/science.adb2956">giant stingray and catfish</a> and critically endangered species. “How do you value a species’ right to exist?” asks Hogan.</p>
<p>Sediment, which fertilizes floodplains and builds up the Mekong Delta, has been relatively easy to quantify, says Schmitt, the Stanford scientist. According to his analysis, the Mekong, in its natural state, delivers <a href="https://doi.org/10.1126/sciadv.aaw2175">160 million tons of sediment each year</a>.</p>
<p>However, dams let through only <a href="https://doi.org/10.1126/sciadv.aaw2175">about 50 million tons</a>, while <a href="https://theconversation.com/the-world-is-facing-a-global-sand-crisis-83557">sand mining</a> in Cambodia and Vietnam extracts 90 million, meaning more sediment is blocked or removed from the river than is delivered to its natural destination. As a result, the Mekong Delta, which naturally would receive much of the sediment, has suffered <a href="https://www.thethirdpole.net/en/livelihoods/in-vietnam-mekong-delta-sand-mining-means-lost-homes-and-fortunes/">tremendous river erosion</a>, with thousands of homes being swept away.</p>
<h2>A potential ‘World Heritage Site’ designation</h2>
<p>A river’s natural services may also include <a href="https://doi.org/10.3390/w15071279">cultural and social benefits</a> that can be difficult to place monetary values on.</p>
<p>A <a href="https://thediplomat.com/2022/12/cambodia-seeks-unesco-world-heritage-status-to-protect-a-mekong-biodiversity-hotspot/">new proposal</a> seeks to designate a bio-rich stretch of the Mekong River in northern Cambodia as a UNESCO World Heritage Site. If successful, such a designation may bring with it a certain amount of prestige that is hard to put in numbers.</p>
<p>The complexities of the Mekong River make our project a challenging undertaking. At the same time, it is the rich diversity of natural benefits that the Mekong provides that make this work important, so that future decisions can be made based on true costs.</p><img src="https://counter.theconversation.com/content/200214/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stefan Lovgren works as a research scientist on the Wonders of the Mekong project, which is funded by USAID, at the University of Nevada, Reno.</span></em></p>Putting a dollar value on nature has staunch opponents who say it’s morally wrong, but without it, building dams and other infrastructure can run roughshod over vital ecosystems.Stefan Lovgren, Research scientist College of Science, University of Nevada, RenoLicensed 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/1962312022-12-12T13:02:44Z2022-12-12T13:02:44ZShark fishing is a global problem that demands local solutions<p>Countries from around the world have <a href="https://www.theguardian.com/environment/2022/nov/18/shark-fin-trade-regulation-cites-panama">voted</a> to limit the global trade in sharks under the Convention on International Trade in Endangered Species (<a href="https://cites.org/eng">Cites</a>). Trade in shark products is a major driver of shark overfishing, leading to the deaths of millions of sharks every year. The new Cites listings aim to keep the international trade of 54 species of shark and ray within sustainable limits.</p>
<p>But there are concerns that Cites listings could unintentionally drive up the price of shark fins and lead to the development of informal shark fin markets. Catches of many species already listed on Cites remain <a href="https://conbio.onlinelibrary.wiley.com/doi/10.1111/csp2.494">valuable</a> for small-scale fishers. And in 2018, <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12457">Cites-listed sharks</a> remained among the leading species traded in contemporary fin markets. </p>
<p>Yet targeted fishing is just part of the issue. Sharks are frequently caught as <a href="https://www.sciencedirect.com/science/article/abs/pii/S0308597X14003546?via%3Dihub">unintentional bycatch</a> by fishers using unselective nets and lines. And since Cites only pertains to international trade, many sharks that are traded and consumed in local or domestic markets are not covered by the regulations. Strict rules protecting sharks in these markets could negatively impact the livelihoods of the small-scale fisheries that depend on them for food and income.</p>
<p>Interventions to reduce catches of threatened shark species must support the rights and welfare of small-scale fishers and be perceived as legitimate. My colleagues and I conducted <a href="https://www.sciencedirect.com/science/article/pii/S0006320722003743?via%3Dihub">research</a> on small-scale fisheries in Indonesia – the world’s <a href="https://www.fao.org/3/i4795e/i4795e.pdf">largest shark fishing nation</a>. </p>
<h2>Fishery-led conservation</h2>
<p>We focused on two taxa, hammerhead sharks and wedgefish. These taxa are both critically endangered and already listed on Cites. </p>
<p>Applying research methods from behavioural science and economics, we interviewed 144 fishers from two villages in the Indonesian shark fishing hotspots of Aceh and Lombok. We presented fishers with a range of conservation scenarios and asked them how their fishing behaviour would change under each.</p>
<p>The first scenario involved the introduction of a new rule stipulating that particular species could not be legally caught or brought to shore. The rule was accompanied with a fine for non-compliance. </p>
<p>The second was a voluntary programme to protect the species. Fishers could choose to reduce their catch or release accidentally caught sharks rather than have a rule imposed on them. </p>
<p>The third approach was based on compensation. Fishers would receive payments for reducing their catch of endangered sharks equivalent to the value they could otherwise have received for it.</p>
<p>For scenarios that involved monetary incentives, we asked fishers to indicate how much they would be willing to pay to continue fishing for endangered sharks or how much they would accept to reduce their catch. We then asked fishers to explain why they would (or why they would not) change their behaviour and how they planned to reduce their catch. </p>
<h2>Support for financial compensation</h2>
<p>The rule and fine scenario was unpopular among the interviewed fishers. Only 50% of those interviewed in Lombok and 20% in Aceh said they would reduce catches in response to the rule and fine scheme. They felt it was impractical, unfair and would negatively impact their welfare due to reducing their income and eliminating a key source of food.</p>
<p><a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12725">Research</a> suggests that if conservation rules are not accepted by local fishers, then they often fail to have a meaningful effect on fisher behaviour.</p>
<p>The voluntary programme was more popular. 55% of fishers in Aceh stated they would voluntarily stop catching wedgefish.</p>
<p>But the fishers expressed a strong preference for a programme based on compensation. 98% of all fishers interviewed said they would stop catching hammerheads while 96% said they would stop catching wedgefish if their lost income was compensated for. Fishers in Aceh were willing to accept less than US$2 (£1.63) per hammerhead shark and US$4-7 (£3.27–5.72) per wedgefish.</p>
<p>Based on data from our study, we estimate that it would cost just US$12,000 (£9,800) per year to save up to 20,000 hammerheads and wedgefish in Aceh.</p>
<p>Although not tested by our study, an approach based on compensation is likely to be more cost-effective than interventions that require enforcement. The exact cost of enforcing a rule and fine policy in Indonesia is unknown, but the annual cost of a single marine patrol boat in the USA is between <a href="https://www.cga.ct.gov/2010/ofarpt/2010OFA-0207.htm">US$40,000 and 100,000 (£32,600 and 81,000)</a>. </p>
<p>The fishers also felt that a compensation scheme was fair and would deliver positive social outcomes for their villages. </p>
<p>We are now <a href="https://www.instagram.com/kebersamaan_untuk_lautan/">trialling</a> such a scheme at the two sites in Aceh and Lombok. Fishers receive financial compensation if they share a video of the safe release of hammerheads or wedgefish. More than 150 animals have been <a href="https://www.youtube.com/watch?v=v1RdxFM5NzI">safely released</a> since April and fishers have so far reported using the payments to support their families and send their children to school.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/v1RdxFM5NzI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Successful releases of hammerhead sharks and wedgefish caught as bycatch in Indonesia.</span></figcaption>
</figure>
<h2>Broader implications</h2>
<p>One size fits all shark conservation measures, based on the enforcement of rules, fail to account for the diversity of fishing contexts and their socio-economic challenges. Cites listings can play a part in supporting the recovery of threatened shark species by better regulating international trade. But nuanced management measures are also needed to reduce catches in the context of limiting harm to small-scale fishing communities.</p>
<p>Governments are expected to agree on a <a href="https://www.cbd.int/article/draft-1-global-biodiversity-framework">new global framework</a> to protect and restore nature at the UN biodiversity summit <a href="https://www.cbd.int/conferences/2021-2022">COP15</a> this month. The long-term vision of this framework is “living in harmony with nature”.</p>
<p>Our research, in line with this vision, offers a scalable method for designing conservation interventions that are appropriate for different fishing contexts. More importantly, it supports the development of solutions that involve the people most affected by conservation.</p><img src="https://counter.theconversation.com/content/196231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hollie Booth receives funding from Save Our Seas Foundation and the Society for Conservation Biology. </span></em></p>Countries have voted to limit the international shark trade, but this fails to account for the diversity in fishing contexts around the world.Hollie Booth, Nature Positive Senior Specialist at The Biodiversity Consultancy, and Post-Doc Research Associate, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1951802022-11-30T13:37:38Z2022-11-30T13:37:38ZBeware of ‘Shark Week’: Scientists watched 202 episodes and found them filled with junk science, misinformation and white male ‘experts’ named Mike<figure><img src="https://images.theconversation.com/files/497069/original/file-20221123-20-w4v0g6.jpg?ixlib=rb-1.1.0&rect=9%2C3%2C2035%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hammerhead sharks schooling near Costa Rica's Cocos Island.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/GqmhHb">John Voo/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>The Discovery Channel’s annual <a href="https://www.discovery.com/shark-week">Shark Week</a> is the <a href="https://www.washingtonpost.com/news/animalia/wp/2018/07/24/shark-scientists-explain-whats-right-and-whats-wrong-with-shark-week/">longest-running cable television series in history</a>, filling screens with sharky content every summer since 1988. It causes one of the largest temporary increases in U.S. viewers’ attention to any <a href="https://doi.org/10.1371/journal.pbio.3000146">science or conservation topic</a>. </p>
<p>It’s also the largest stage in marine biology, giving scientists who appear on it access to an audience of millions. Being featured by high-profile media outlets can help researchers attract attention and funding that can help super-charge their careers. </p>
<p>Unfortunately, Shark Week is also a missed opportunity. As scientists and conservationists <a href="https://www.outsideonline.com/culture/books-media/what-shark-experts-really-think-about-shark-week/">have long argued</a>, it is a major source of <a href="https://www.npr.org/2015/07/06/420326546/after-sketchy-science-shark-week-promises-to-turn-over-a-new-fin">misinformation</a> and <a href="https://www.bostonmagazine.com/news/2013/08/05/shark-week-megalodon-fake-discovery-channel/">nonsense</a> about sharks, the scientists who study them, and how people can help protect endangered species from extinction.</p>
<p>I am a <a href="https://scholar.google.com/citations?user=xb7noGAAAAAJ&hl=en">marine biologist</a> who worked with five colleagues in 2022 to <a href="https://doi.org/10.1371/journal.pone.0256842">scientifically analyze the content of Shark Week episodes</a>. We tracked down copies of 202 episodes, watched them all and coded their content based on more than 15 variables, including locations, which experts were interviewed, which shark species were mentioned, what scientific research tools were used, whether the episodes mentioned shark conservation and how sharks were portrayed. </p>
<p>Even as longtime Shark Week critics, we were staggered by our findings. The episodes that we reviewed were full of incorrect information and provided a wildly misleading picture of the field of shark research. Some episodes <a href="https://www.earthtouchnews.com/oceans/sharks/experts-shark-weeks-zombie-sharks-harasses-animals/">glorified wildlife harassment</a>, and many missed countless chances to teach a massive audience about shark conservation. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tKXd8Ud1sOo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Sharks are apex predators that are key to maintaining healthy ecosystems, but a 2020 study that surveyed 371 coral reefs found that 20% had no sharks present.</span></figcaption>
</figure>
<h2>Spotlight real solutions</h2>
<p>First, some facts. <a href="https://www.britannica.com/topic/list-of-sharks-skates-and-rays-2075391">Sharks and their relatives</a>, such as rays and skates, are among the most threatened vertebrate animals on Earth. About one-third of all known species are at risk of extinction, thanks mainly to <a href="https://doi.org/10.1016/j.cub.2021.08.062">overfishing</a>. </p>
<p>Many policy solutions, such as setting fishing quotas, creating protected species lists and delineating no-fishing zones, are enacted <a href="https://doi.org/10.1111/acv.12265">nationally or internationally</a>. But there also are countless situations in which increased public attention can help <a href="https://www.press.jhu.edu/books/title/12267/why-sharks-matter">move the conservation needle</a>. For instance, consumers can avoid buying seafood produced using <a href="https://www.montereybayaquarium.org/act-for-the-ocean/sustainable-seafood">unsustainable fishing methods</a> that may accidentally catch sharks.</p>
<p>Conversely, focusing on the wrong problems <a href="https://doi.org/10.1139/facets-2020-0058">does not lead to useful solutions</a>. As one example, enacting a ban on shark fin sales in the U.S. would have little effect on global shark deaths, since the U.S. is only involved in about 1% of the global fin trade, and could <a href="https://doi.org/10.1016/j.marpol.2017.08.026">undermine sustainable U.S. shark fisheries</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A shark caught in a fishing net dangles over the side of a boat with a crew member reaching out." src="https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&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 crew member aboard a commercial fishing boat off the coast of Maine tries to cut a shark loose from a gillnet. Sharks often are caught accidentally by fishermen pursuing other species.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/crew-member-aboard-a-commercial-fishing-boat-tries-to-cut-a-news-photo/1243631026">Mailee Osten-Tan/SOPA Images/LightRocket via Getty Images</a></span>
</figcaption>
</figure>
<p>The Discovery Channel claims that by attracting massive audiences, Shark Week <a href="https://www.washingtonpost.com/news/animalia/wp/2018/07/24/shark-scientists-explain-whats-right-and-whats-wrong-with-shark-week/">helps educate the public</a> about shark conservation. But most of the shows we reviewed didn’t mention conservation at all, beyond vague statements that sharks need help, without describing the threats they face or how to address them. </p>
<p>Out of 202 episodes that we examined, just six contained any actionable tips. Half of those simply advised against eating <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/shark-fin-soup">shark fin soup</a>, a traditional Asian delicacy. Demand for shark fin soup can contribute to the gruesome practice of “<a href="https://www.discoverwildlife.com/animal-facts/fish/what-is-shark-finning-and-why-is-it-a-problem/">finning</a>” – cutting fins off live sharks and throwing the mutilated fish overboard to die. But finning is not the biggest threat to sharks, and most U.S.-based Shark Week viewers don’t eat shark fin soup.</p>
<h2>Spotlighting divers, not research</h2>
<p>When we analyzed episodes by the type of scientific research they featured, the most frequent answer was “no scientific research at all,” followed by what we charitably called “other.” This category included nonsense like building a submarine that looks like a shark, or a “<a href="https://www.ffjournal.net/item/12437-wasp-water-armor-shark-protection.html">high tech” custom shark cage</a> to observe some aspect of shark behavior. These episodes focused on alleged risk to the scuba divers shown on camera, especially when the devices inevitably failed, but failed to address any research questions.</p>
<p>Such framing is not representative of <a href="https://doi.org/10.1643/OT-19-179R">actual shark research</a>, which uses methods ranging from tracking tagged sharks via satellite to genetic and paleontological studies conducted entirely in labs. Such work may not be as exciting on camera as divers surrounded by schooling sharks, but it generates much more useful data. </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 findings from his lab’s analysis of shark genetics.</span></figcaption>
</figure>
<h2>Who’s on camera</h2>
<p>We also were troubled by the “experts” interviewed on many Shark Week shows. The most-featured source, underwater photographer <a href="https://www.youtube.com/watch?v=B7t7jl8e0Mw">Andy Casagrande</a>, is an award-winning cameraman, and episodes when he stays behind the camera can be great. But given the chance to speak, he regularly claims the mantle of science while making dubious assertions – for example, that <a href="https://twitter.com/ABC4EXPLORE/status/1285972513328070689">shark diving while taking LSD</a> is a great way to learn about these animals – or presents well-known shark behaviors as new discoveries that he made, while <a href="https://www.mensjournal.com/adventure/mega-shark-episode-criticized-as-a-low-point-for-shark-week/">misrepresenting what those behaviors mean</a>.</p>
<p>Nor does Shark Week accurately represent experts in this field. One issue is ethnicity: Three of the five most-featured locations on Shark Week are Mexico, South Africa and the Bahamas, but we could count on one hand the number of non-white scientists who we saw featured in shows about their own countries. It was far more common for Discovery to fly a white male halfway around the world than to feature a local scientist. </p>
<p>Moreover, while <a href="https://doi.org/10.3389/feduc.2022.842618">more than half of U.S. shark scientists are female</a>, you <a href="https://www.scientificamerican.com/article/the-dark-side-of-being-a-female-shark-researcher/">wouldn’t know this from watching Shark Week</a>. Among people who we saw featured in more than one episode, there were more white male non-scientists named Mike than women of any profession or name. </p>
<p>In contrast, the Discovery Channel’s chief competitor, National Geographic, is partnering with the professional organization <a href="https://www.misselasmo.org/">Minorities in Shark Sciences</a> to <a href="https://www.nationalgeographic.com/magazine/article/building-a-community-and-fostering-a-love-for-sharks">feature diverse experts</a> on its shows.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1585646957233512450"}"></div></p>
<h2>More substance and better representation</h2>
<p>How could Shark Week improve? Our paper makes several recommendations, and we also participated in a workshop, highlighting diverse voices in our field from all over the world, that focused on <a href="https://safesharks.org/diversifying-shark-media/">improving representation of scientists in shark-focused media</a> </p>
<p>First, we believe that not every documentary needs to be a dry, boring science lecture, but that the information shared on marine biology’s biggest stage should be factually correct and useful. Gimmicky concepts like Discovery’s “<a href="https://www.discovery.com/shows/naked-and-afraid/episodes/naked-and-afraid-of-sharks-2">Naked and Afraid of Sharks 2</a>” – an endurance contest with entrants wearing masks, fins and snorkels, but no clothes – show that people will watch anything with sharks in it. So why not try to make something good? </p>
<p>We also suggest that more scientists seek out media training so they can take advantage of opportunities like Shark Week without <a href="https://gizmodo.com/shark-week-lied-to-scientists-to-get-them-to-appear-in-1619280737">being taken advantage of</a>. Similarly, it would be great to have a “Yelp”-like service that scientists could use to rate their experiences with media companies. Producers who want to feature appropriately diverse scientists can turn to databases like <a href="https://500womenscientists.org/">500 Women Scientists</a> and <a href="https://diversifyeeb.com/">Diversify EEB</a>. </p>
<p>For a decade, concerned scientists and conservationists have <a href="https://www.npr.org/2015/07/06/420326546/after-sketchy-science-shark-week-promises-to-turn-over-a-new-fin">reached out to the Discovery Channel</a> about our concerns with Shark Week. As our article recounts, Discovery has <a href="https://doi.org/10.1371/journal.pone.0256842">pledged in the past</a> to present programming during Shark Week that puts more emphasis on science and less on entertainment – and some episodes <a href="https://twitter.com/whysharksmatter/status/620417258406318080?lang=en">have shown improvement</a>.</p>
<p>But our findings show that many Shark Week depictions of sharks are still problematic, pseudoscientific, nonsensical or unhelpful. We hope that our analysis will motivate the network to use its massive audience to help sharks and elevate the scientists who study them. </p>
<p><em>Editor’s note: The Conversation US contacted Warner Brothers Discovery by phone and email for comment on the study described in this article. The network did not immediately respond or offer comment.</em></p><img src="https://counter.theconversation.com/content/195180/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 study offers evidence that marine biology’s biggest stage is broken, and suggests ways to fix it.David Shiffman, Faculty Research Associate in Marine Biology, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1944772022-11-16T19:33:08Z2022-11-16T19:33:08ZWarming waters in the Gulf of St. Lawrence are disrupting commercial fishing<figure><img src="https://images.theconversation.com/files/494889/original/file-20221111-20-infz0p.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C982%2C661&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The warming of the Gulf of St. Lawrence is causing upheaval in the balance of species, with direct repercussions on the commercial fishing sector. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The latest report on the state of the Gulf of St. Lawrence ecosystem could not be clearer: <a href="https://publications.gc.ca/collections/collection_2022/mpo-dfo/fs70-5/Fs70-5-2022-034-eng.pdf">It shows undeniably that the system is warming rapidly</a>.</p>
<p>This warming is occurring both in its surface layer, which is directly exposed to global warming, and in its deepest layer, due to the recent increase in the inflow of warm water from the Gulf Stream into its deep channels through the Cabot Strait.</p>
<p>At depth, <a href="https://theconversation.com/why-the-st-lawrence-estuary-is-running-out-of-breath-184626">warming is combined with a significant decrease in oxygen levels</a>, which amplifies habitat changes for marine species.</p>
<p>By affecting both near-surface and deep-sea organisms, the current warming is influencing the entire ecosystem and provoking a real upheaval in the balance of the species living there. This is having <a href="https://theconversation.com/why-canada-shuttered-some-mackerel-and-spring-herring-fisheries-in-quebec-and-atlantic-canada-181143">direct repercussions on the commercial fishing sector</a>.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
<hr>
<p>As a Canada Research Chair in fisheries ecology, I am interested in the causes and consequences of changes in the dynamics of commercially exploited species. In this article, I explain the changes underway in the balance of species that inhabit the bottom waters of the Gulf of St. Lawrence.</p>
<h2>The decline of cold water species</h2>
<p>Following the historic collapse of Atlantic cod stocks in the early 1990s, <a href="https://cdnsciencepub.com/doi/full/10.1139/f2011-007">caused by a combination of overfishing and very cold conditions</a>, species of Arctic origin, including northern shrimp, snow crab and Greenland halibut, took advantage of the cooling and a decrease in predation and competition in the system to settle comfortably in the Gulf of St. Lawrence.</p>
<p>The dominance of these species lasted for more than two decades, allowing for the development of lucrative fisheries, whose <a href="https://www.dfo-mpo.gc.ca/stats/commercial/sea-maritimes-eng.htm">revenues not only replaced, but greatly exceeded the value of revenues from the cod fishery prior to its collapse</a>. However, as these species now face rapid warming of their habitat, their abundance is declining.</p>
<h2>Northern shrimp in hot water</h2>
<p>Shrimp can be considered a true barometer of the state of the demersal marine ecosystem, i.e. the layer of water located near the bottom, since its distribution fluctuates rapidly according to changes in the temperature of the environment. Preferring waters with temperatures between 1°C and 6°C, shrimp has seen a marked decrease in its habitat over the last decade.</p>
<p>Data from the monitoring survey conducted by Fisheries and Oceans Canada show that, due to the warming of the shrimp’s habitat, the <a href="https://publications.gc.ca/collections/collection_2022/mpo-dfo/fs70-6/Fs70-6-2022-006-eng.pdf">area it occupies has decreased by half since 2008, and the abundance estimate in 2021 is among the lowest values in the history of monitoring this resource</a>. This decrease in abundance has resulted in a 12 per cent reduction in allowable catch in 2022. With an additional 18 per cent reduction announced for 2023 and a high cost of diesel, the <a href="https://www.cbc.ca/news/canada/montreal/sept-isles-matane-gaspe-quebec-fisheries-and-oceans-1.4214075">profitability of businesses that rely on this resource is threatened in the near term</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="graph showing the decline in northern shrimp abundance" src="https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495415/original/file-20221115-14-c0nvym.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&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 combined biomass of the four northern shrimp stocks in the Gulf of St. Lawrence has been declining since 2004. The data is taken from the latest Fisheries and Oceans Canada stock assessment report.</span>
<span class="attribution"><span class="source">(Dominique Robert)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Snow crab and Greenland halibut: A fragile balance</h2>
<p>Like the northern shrimp, the snow crab and Greenland halibut are two species of Arctic origin whose stocks in the St. Lawrence are at the southern limit of their distribution. Any warming of the waters of the Gulf, which are already warmer than the average for their habitat, can thus negatively affect the productivity of these stocks.</p>
<p>Snow crab are particularly vulnerable during their early life stages, and more specifically when juveniles are settling on the sea floor. <a href="https://www.int-res.com/articles/meps2003/256/m259p117.pdf">Their survival then depends on the availability of very cold water, with temperatures between 0°C and 2°C</a>. At present, snow crab abundance remains relatively high, especially in the southern Gulf of St. Lawrence, where the largest stock is located. However, <a href="https://publications.gc.ca/collections/collection_2020/mpo-dfo/Fs97-18-334-eng.pdf">ocean models indicate that by 2050, bottom water temperatures in this area of the Gulf will exceed 3°C</a>, which will greatly reduce the potential for maintaining high abundance of the species and could lead to a collapse of the stocks in the medium term.</p>
<p>The abundance of Greenland halibut — the groundfish species that has been the most lucrative for fishers since the 1990s — <a href="https://www.dfo-mpo.gc.ca/csas-sccs/Publications/SAR-AS/2021/2021_017-eng.html">has been declining for 15 years</a>. This decline has resulted in a decrease in allowable catch of almost 50 per cent in five years, with the latter dropping from 4,500 to 2,400 tons from 2017 to 2022. While the exact causes of the decline of this stock in Gulf of St. Lawrence waters remain uncertain, warming and declining oxygen levels underway in deep channel waters are considered the most likely explanations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="graph presenting the evolution of snow crab and halibut abundance" src="https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495416/original/file-20221115-21-w4nikb.png?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"></a>
<figcaption>
<span class="caption">While the biomass of the southern Gulf of St. Lawrence snow crab stock remains stable, the abundance index of Greenland halibut shows a decrease in this stock since 2004. The data are from the latest Fisheries and Oceans Canada stock assessment reports.</span>
<span class="attribution"><span class="source">(Dominique Robert)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Lobster and redfish: A massive red tide</h2>
<p>In addition to the Atlantic halibut stock, which has recovered and is currently doing very well, two reddish-coloured species are experiencing a remarkable population explosion in the Gulf of St. Lawrence. These are the American lobster, which lives on the bottom in coastal areas, and the redfish, a fish that is distributed on the bottom in deep waters.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="lobster in its natural habitat" src="https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495422/original/file-20221115-11-zsbgg4.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">Lobster is now by far the most lucrative resource in Atlantic Canada.</span>
<span class="attribution"><span class="source">(Jean-Daniel Tourangeau Larivière)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Lobster is now by far the most lucrative resource in Atlantic Canada. For example, <a href="https://www.dfo-mpo.gc.ca/stats/commercial/land-debarq/sea-maritimes/s2020pv-eng.htm">for Québec fishers, it alone represented 42 per cent of total revenues in 2020</a>. In the southern Gulf of St. Lawrence, <a href="https://cfim.ca/95411-2/">Magdalen Islands fishers landed record catches in 2022</a>. In addition, with the gradual warming of the coastal areas of the northern Gulf of St. Lawrence, lobster is expanding there. <a href="https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/41074415.pdf">Off the North Shore, the increase in catches between 2015 and 2021 varied from 388 per cent to 850 per cent depending on the sector</a>, which represents a real windfall for fishers, who received <a href="https://www.pecheimpact.com/une-bonne-saison-pour-les-homardiers-mais-une-diminution-des-prises-a-cause-dun-lent-debut-de-saison/">approximately $8 per pound of lobster landed in 2022</a>.</p>
<p>Redfish, whose stocks had collapsed shortly after cod in the 1990s, took the fisheries sector by surprise by <a href="https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/40960729.pdf">making a strong comeback in the 2010s</a>. <a href="https://academic.oup.com/icesjms/article-abstract/78/10/3757/6423499">This dramatic return occurred as a result of strong survival of juvenile redfish born in the 2011-2013 period, likely due to favourable environmental conditions for the larvae</a>.</p>
<p>These fish, which are now about 10 years old, are reaching the minimum size allowed for commercial capture. The return of large-scale fishing is therefore imminent, but the industry faces major challenges. Indeed, the anticipated value per unit weight of these small fish is about ten times less than that of lobster. Therefore, it will not be simple to make a sustainable harvest of this resource profitable.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="graph showing the increase in abundance of lobster and redfish" src="https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495417/original/file-20221115-23-1gm4gz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Redfish and lobster have experienced a population explosion in the Gulf of St. Lawrence over the past 15 years. The redfish biomass data are taken from the latest Fisheries and Oceans Canada stock assessment report, while the lobster landings data are the sum of catches from Québec, New Brunswick and Prince Edward Island.</span>
<span class="attribution"><span class="source">(Dominique Robert)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Feedback loops generated by the relationships between species</h2>
<p>The return of redfish to the waters of the St. Lawrence could well mean that, for cold-water species, there will be more bad news. Indeed, <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.963039/full">recent research on the diet of redfish shows that once they reach a size of 25 to 30 cm, northern shrimp become one of their main prey</a>. However, <a href="https://www.dfo-mpo.gc.ca/csas-sccs/Publications/SAR-AS/2022/2022_039-eng.html">redfish born in the 2010s were about 24 cm in 2021</a>. Although at this time we cannot accurately determine the amount of shrimp needed to sustain the <a href="https://www.dfo-mpo.gc.ca/csas-sccs/Publications/SAR-AS/2022/2022_039-eng.html">2.8 million tons of redfish currently inhabiting the St. Lawrence</a>, this predation pressure is expected to accelerate the decline of shrimp, whose productivity is already negatively impacted by warming waters.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Goldfish on a conveyor belt" src="https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495421/original/file-20221115-17-6rv7ka.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">University research teams from the Ressources Aquatiques Québec group are teaming up with those from Fisheries and Oceans Canada’s Maurice Lamontagne Institute as part of a program to better understand the ecology and dynamics of redfish.</span>
<span class="attribution"><span class="source">(Joëlle Guitard)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Furthermore, the <a href="https://publications.gc.ca/collections/collection_2020/mpo-dfo/Fs97-6-3383-eng.pdf">redfish diet shows a significant level of overlap with that of Greenland halibut</a>. Greenland halibut may therefore be competing for the resource at a time when the quality of its habitat is deteriorating. Such impacts caused by predator-prey relationships thus add to the physical changes in the environment to accelerate the rate of change in species abundance, which could cause the ecosystem to shift to a new steady state.</p>
<h2>Research to guide the future</h2>
<p>The return of redfish from very low abundance is a big surprise to scientists and a destabilizing event for the fisheries sector. It is, therefore, important to have a precise understanding of the causes and consequences of the demographic explosion of this stock in order to facilitate the sustainable development of the sector. To this end, university research teams from the <a href="https://www.raq.uqar.ca/">Ressources Aquatiques Québec</a> group are teaming up with those from the <a href="https://www.qc.dfo-mpo.gc.ca/en/maurice-lamontagne-institute">Maurice Lamontagne Institute</a> of Fisheries and Oceans Canada as part of a program to better understand the ecology and dynamics of redfish.</p>
<p>Ultimately, the results of these multidisciplinary collaborations will provide valuable elements for developing an ecosystem approach to fisheries management, and thus promote the sustainable exploitation of our resources.</p><img src="https://counter.theconversation.com/content/194477/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dominique Robert receives funding from the Canada Research Chairs Program, the Natural Sciences and Engineering Research Council of Canada, and Fisheries and Oceans Canada.</span></em></p>The warming observed in the Gulf of St. Lawrence is causing upheaval in the balance of the species living there. That is having direct repercussions on the commercial fishing sector.Dominique Robert, Professeur et Chaire de recherche du Canada en écologie halieutique, Université du Québec à Rimouski (UQAR)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1923562022-10-19T16:52:55Z2022-10-19T16:52:55ZFacing the dual threat of climate change and human disturbance, Mumbai – and the world – should listen to its fishing communities<figure><img src="https://images.theconversation.com/files/489362/original/file-20221012-24-hll9p1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Koli community depend on fishing, but fish stocks off Mumbai's coast have been declining.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mumbai-india-september-10-2017-south-1749662051">Akella Srinivas Ramalingaswami/Shutterstock</a></span></figcaption></figure><p>Coastal cities and settlements are at the forefront of climate disruption. Rising sea levels, warmer seas and changes in rainfall patterns are together creating conditions that mean misery for coastal dwellers.</p>
<p>Disasters triggered by extreme weather often make headlines, but many problems linked to the climate are harder to see. These include the effects of warmer sea temperatures on marine ecosystems, the encroachment of seawater into once-fertile land, and coastal erosion.</p>
<p>Climate risks vary for coastal cities around the world. But according to the Intergovernmental Panel on Climate Change, people living in coastal settlements with high social inequality <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">are particularly at risk</a>. This includes cities with a high proportion of informal settlements and those built near river deltas.</p>
<p>The Koli people are one such community. As the original inhabitants of Mumbai, they are spread across a number of historic fishing villages on the city’s coast. But they have steadily been marginalised. Mumbai’s <a href="https://www.mcgm.gov.in/irj/go/km/docs/documents/EODB/Construction%20Permit/Related%20Circulars/DCPR-%202034%20and%20Notification.pdf">official development plan</a> ignores the role of the Koli, and the ecosystems they depend on, in reducing the climate risks facing the city. </p>
<p>This has forced the community to take risk mitigation into their own hands. Through our work with the Koli community, we have seen how their response to human threats has the potential to create a city more resilient to environmental change.</p>
<h2>Mumbai’s environmental problem</h2>
<p>In Mumbai, enormous wealth co-exists with poverty. Largely built on reclaimed land, the city has undergone rapid development.</p>
<p>Poor waste management, property development and increasingly frequent extreme weather have reduced mangrove cover and polluted the city’s coastal waters. Mangroves are important breeding grounds for a diverse range of aquatic species. Many of these species, such as the <a href="https://www.theguardian.com/environment/blog/2013/mar/22/bombay-duck-mumbai-fish">Bombay Duck</a> and <a href="https://ruralindiaonline.org/en/articles/the-shrinking-pomfret-of-suburban-mumbai/">Pomfret</a>, are vital sources of income for Koli fishers and are key to mangrove biodiversity.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="4 rows of bombay duck, a local fish, hanging to dry in front of a calm sea." src="https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489364/original/file-20221012-14-2ag90b.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">Bombay duck, a vital source of income for the Koli community, drying on a beach.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mumbai-india-bombil-bombay-duck-kept-1750309199">Akella Srinivas Ramalingaswami/Shutterstock</a></span>
</figcaption>
</figure>
<p>But fish stocks are disappearing fast. Environmental degradation combined with intensive trawling has led to <a href="https://www.cmfri.org.in/uploads/files/Attachment%201.%20Major%20Research%20Achievemnt_Mumbai.pdf">declining catches</a> for traditional fishers. This has affected livelihoods, with Koli women feeling the impact particularly strongly due to their prominent role in processing and selling fish.</p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S1385110121001684">Studies</a> have also shown that mangrove forests protect coastal areas from storm surges and coastal erosion. Reduced mangrove cover means extreme weather events now inflict <a href="https://www.indiaspend.com/climate-change/exposed-at-sea-fishers-need-better-insurance-to-manage-climate-risks-781266">severe damage to fishing infrastructure</a>. <a href="https://moes.gov.in/sites/default/files/RS-in-English-4026-07042022.pdf">Cyclone Tauktae</a> in 2021 inflicted losses of 10 billion rupees (£109,000) to coastal fishers – damage to fishing boats alone was worth 250,000 rupees (£2,700).</p>
<h2>Taking the initiative</h2>
<p>Following <a href="https://earthobservatory.nasa.gov/images/148325/cyclone-tauktae-strikes-india">Cyclone Tauktae</a>, the Koli produced reports documenting the changing frequency and intensity of cyclones affecting the region. These reports, supplemented by <a href="https://qz.com/india/2030290/mumbais-koli-fishermen-cope-with-climate-change-and-cyclones/">media coverage</a>, have raised awareness of the community’s vulnerability towards climate change.</p>
<p>This has allowed the Koli to collaborate with various groups to reduce their vulnerability. We have been working with the Koli community through our own research project, <a href="https://tapestry-project.org/">Tapestry</a>. Our research has involved creating photographs and maps with the community to build a more comprehensive understanding of the consequences of climate change and environmental degradation for the region. This has highlighted the importance of mangroves for marine biodiversity and flooding protection.</p>
<figure class="align-center ">
<img alt="An aerial shot of a mangrove forest in the foreground of a large sprawling city." src="https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489415/original/file-20221012-19-1diumc.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">Mumbai’s mangrove forests are crucial for marine biodiversity and flood prevention.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/view-boats-mangroves-gorai-mumbai-india-1008986491">Viren Desai/Shutterstock</a></span>
</figcaption>
</figure>
<p>The efforts of the <a href="https://cat.org.in/">Conservation Action Trust</a>, a Mumbai-based non-profit organisation that aims to protect forests and wildlife, have also been key in protecting mangroves. They found that mangroves were being cleared to make way for golf courses, residential buildings, rubbish dumps and transport infrastructure. They were instrumental in the development of the <a href="https://mangroves.maharashtra.gov.in/">Mangrove Cell</a>, a government agency that monitors efforts to conserve and enhance mangrove cover in India’s western Maharashtra state.</p>
<p>Addressing water pollution also emerged as a priority through discussions with the Koli community. Our project partner <a href="https://bombay61.blogspot.com/">Bombay61</a> has since implemented measures to <a href="https://tapestry-project.org/2022/08/08/catching-plastic-mumbais-koli-community-uses-fishing-nets-to-tackle-pollution/">improve water quality</a>. Over three days, a pilot trial of net filters collected around 500kg of waste from a single creek. This initiative also challenges the perception of creeks as “drains” or “sewers”.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A cluster of plastic bottles and litter floating in brown water." src="https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489745/original/file-20221014-23-kcev7m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The coastal waters the Koli depend on are heavily polluted.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mumbai-india-november-11-2017-rubbish-759116230">TK Kurikawa/Shutterstock</a></span>
</figcaption>
</figure>
<p>Engagement between the Koli community, environmental organisations, government officials and local public events and exhibitions has allowed more equitable solutions to human threats to be explored. These highlight the importance of local communities to resource governance and urban planning, and could help dissuade the government from destructive future development plans.</p>
<p>The lessons from the Koli experience extend beyond just Mumbai. While each coast and city will face different threats, the seeds of responses can be found in the people who know and understand the environments in which they live. Working with grassroots methods and groups can reveal how action can respond to local needs and address more than just physical climate risks.</p>
<p>If local strategies can be scaled up, they could transform urban planning and climate change mitigation. These strategies must address the need to adapt to climate change and minimise human disturbance. Paying attention to local people’s struggles and harnessing their ideas can be an essential part of creating cities that are more resilient to future threats.</p><img src="https://counter.theconversation.com/content/192356/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lyla Mehta has based this article on research conducted for the Tapestry project. This project is financially supported by the Belmont Forum and NORFACE Joint Research Programme on Transformations to Sustainability, which is co-funded by ESRC, ISC, JST, RCN and the European Commission through Horizon 2020 under grant agreement No 730211</span></em></p><p class="fine-print"><em><span>D Parthasarathy receives funding from Belmont Forum and International Science Council Paris. </span></em></p><p class="fine-print"><em><span>Shibaji Bose receives funding from Belmont-funded Tapestry project</span></em></p>Facing human threats, Mumbai’s Koli community are taking risk reduction into their own hands – other vulnerable coastal settlements should take note.Lyla Mehta, Professorial Fellow, Institute of Development StudiesD Parthasarathy, Professor of Sociology, Indian Institute of Technology BombayShibaji Bose, PhD Student in Community Voices, National Institute of Technology DurgapurLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1860312022-09-12T12:13:41Z2022-09-12T12:13:41ZHow you can help protect sharks – and what doesn’t work<figure><img src="https://images.theconversation.com/files/483766/original/file-20220909-1182-fq1lk.jpg?ixlib=rb-1.1.0&rect=0%2C181%2C2160%2C1435&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Whitetip sharks amid a school of anthias near Jarvis island in the South Pacific.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/JXZz61">Kelvin Gorospe, NOAA/NMFS/Pacific Islands Fisheries Science Center Blog/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Sharks are some of the most ecologically important and most threatened animals on Earth. Recent reports show that <a href="https://doi.org/10.1016/j.cub.2021.08.062">up to one-third of all known species of sharks and their relatives, rays</a>, are threatened with extinction. Unsustainable overfishing is the biggest threat by far. </p>
<p>Losing sharks can disrupt coastal food webs that billions of people depend on for food. When food chains lose their top predators, the rest can unravel as <a href="https://www.nsf.gov/news/news_summ.jsp?cntn_id=121020">smaller prey species multiply</a>. </p>
<p>In my years of talking with the public about sharks and ocean conservation, I’ve found that many people care about sharks and want to help but don’t know how. The solutions can be quite technical, and it’s challenging to understand and appreciate the scale and scope of some of the threats. </p>
<p>At the same time, there is an enormous amount of oversimplification and even misinformation about these important topics, which can lead well-intentioned people to support policies that experts know won’t work. </p>
<p>I am a <a href="https://scholar.google.com/citations?user=xb7noGAAAAAJ&hl=en">marine conservation biologist</a> and have sought to improve this situation by <a href="https://doi.org/10.1111/cobi.12668">surveying shark researchers</a> and helping scientists identify <a href="https://doi.org/10.1111/csp2.12629">research topics that can advance conservation</a>. I’ve also written a book, “<a href="https://www.press.jhu.edu/books/title/12267/why-sharks-matter">Why Sharks Matter: A Deep Dive With the World’s Most Misunderstood Predator</a>.” Here are three ways that anyone can make a difference for sharks and avoid taking steps that are ineffective or even harmful.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tKXd8Ud1sOo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A 2020 study that surveyed 371 reefs found that sharks had virtually disappeared from about 20% of them.</span></figcaption>
</figure>
<h2>Don’t eat unsustainable seafood</h2>
<p>The No. 1 threat to sharks and rays – and arguably, to marine biodiversity in general – is unsustainable overfishing. Some fishing methods <a href="https://celebrating200years.noaa.gov/visions/coral/side3.html">are incredibly destructive</a> to marine life and habitats. </p>
<p>They can also produce high rates of <a href="https://www.fisheries.noaa.gov/insight/understanding-bycatch">bycatch</a> – the unintended catch of nontarget species. For example, fishermen pursuing tuna may accidentally catch sea turtles or sharks swimming near the tuna. </p>
<p>The single most effective thing that individual consumers can do is to avoid seafood produced using these harmful methods. This does not mean completely avoiding seafood, as <a href="https://www.theguardian.com/commentisfree/2019/may/09/seas-stop-eating-fish-fishing-industry-government">some advocates urge</a>. Seafood is healthy, delicious and culturally important, and there are environmentally friendly ways of catching it sustainably. There are even <a href="https://doi.org/10.1016/j.cub.2016.12.017">sustainable fisheries for sharks</a>. </p>
<p>Reputable organizations such as California’s <a href="https://www.montereybayaquarium.org/">Monterey Bay Aquarium</a> publish <a href="https://www.seafoodwatch.org/">sustainable seafood guides</a> that rate different types of seafood based on how they are caught or raised. While experts may quibble over details of some of these rankings, consumers can follow these guidelines and know that they are helping to protect sharks and ocean life in general.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CUvmPhQMu-5/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Support reputable environmental nonprofits, not harmful extremists</h2>
<p>Lots of great environmental nonprofit organizations work on shark issues and offer opportunities to get involved, such as donating money and communicating with elected officials and other decision-makers. In my book, I describe the work of many of these groups, including my favorite, <a href="https://sharkadvocates.org/">Shark Advocates International</a>.</p>
<p>Unfortunately, some organizations promote pseudoscience that doesn’t help anyone or anything. In a 2021 study, colleagues and I surveyed employees of 78 nonprofits that work on shark conservation issues to understand whether and how these organizations engaged with the science of shark conservation. </p>
<p>We found that a small but vocal minority had never read scientific reports or spoken with scientists, and held <a href="https://doi.org/10.1038/s41598-021-96020-4">blatantly incorrect and harmful views that cannot help sharks</a>. For example, some organizations are trying to get certain airlines to stop carrying shark products like dried fins, without acknowledging that well over 95% of fins are shipped by sea or that sustainable sources of these fins exist. </p>
<p>One of my particular pet peeves is amateur online petitions that may not reflect actual conditions. For example, in the spring of 2022, some 60,000 people signed a petition calling for Florida to ban the practice of shark finning – without recognizing that Florida had <a href="https://twitter.com/WhySharksMatter/status/1516046259748020225">banned shark finning in the early 1990s</a>. As I explain in my book, it is essential to identify organizations that use science in support of worthwhile conservation goals and avoid promoting others that do not.</p>
<h2>Look to experts</h2>
<p>Many ocean science, management and conservation experts are <a href="https://doi.org/10.1002/fsh.10031">active on social media</a>. Following them is a great way to learn about fascinating new scientific discoveries and conservation issues. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1567886741985533953"}"></div></p>
<p>Unfortunately, sharks also get a lot of sensational coverage in the media, and well-intentioned but uninformed people often spread misinformation on social media. For example, you may have seen posts celebrating Hawaii for <a href="https://twitter.com/teamsharkwater/status/1486795216682110982?s=20&t=ulMIBdE-3wn7JS_Mfrzf0w">banning shark fishing in its waters</a> – but these posts don’t note that about 99% of fishing in Hawaii occurs in federal waters. </p>
<p>Don’t take the bait. By getting your information from reliable sources, you can help other people learn more about these fascinating, ecologically important animals, why they need humans’ help and the most effective steps to take.</p><img src="https://counter.theconversation.com/content/186031/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>Sharks are much more severely threatened by humans than vice versa. A marine biologist explains how people can help protect sharks and why some strategies are more effective than others.David Shiffman, Post-Doctoral and Research Scholar in Marine Biology, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1894712022-09-12T01:00:25Z2022-09-12T01:00:25ZWhere is your seafood really from? We’re using ‘chemical fingerprinting’ to fight seafood fraud and illegal fishing<figure><img src="https://images.theconversation.com/files/483426/original/file-20220908-9292-419un6.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C6000%2C3359&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/assorted-seafood-in-a-market-2031994/">Photo by Chait Goli/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Fake foods are invading our supermarkets, as foods we love are substituted or adulterated with lower value or unethical <a href="https://www.emerald.com/insight/content/doi/10.1108/JFC-09-2020-0179/full/html">goods</a>.</p>
<p>Food fraud threatens human health but is also bad news for industry and sustainable food <a href="https://www.fao.org/documents/card/en/c/I8791EN/">production</a>. Seafood is one of <a href="https://www.sciencedirect.com/science/article/pii/S0305750X14003246">most traded food products</a> in the world and reliant on convoluted supply chains that leave the the door wide open for seafood <a href="https://link.springer.com/article/10.1007/s12571-018-0826-z">fraud</a>.</p>
<p>Our new <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/faf.12703">study</a>, published in the journal <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/faf.12703">Fish and Fisheries</a>, showcases a new approach for determining the provenance or “origin” of many seafood species.</p>
<p>By identifying provenance, we can detect fraud and empower authorities and businesses to stop it. This makes it more likely that the food you buy is, in fact, the food you truly want to eat.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman walks through a seafood market." src="https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483431/original/file-20220908-18-ivhoux.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Seafood is one of the most traded food product in the world.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/person-waling-on-market-in-meat-and-fish-section-123013/">Photo by Saya Kimura/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-technology-will-help-fight-food-fraud-85783">How technology will help fight food fraud</a>
</strong>
</em>
</p>
<hr>
<h2>Illegal fishing and seafood fraud</h2>
<p>Wild-caught seafood is vulnerable to illegal, unreported, and unregulated fishing.</p>
<p>Illegal, unreported, and unregulated fishing can have a devastating impact on the marine environment because:</p>
<ul>
<li><p>it is a major cause of overfishing, constituting an estimated one-fifth of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/faf.12462">seafood</a> </p></li>
<li><p>it can destroy marine habitats, such coral reefs, through destructive fishing methods such as blast bombing and cyanide fishing</p></li>
<li><p>it can significantly harm wildlife, such as albatross and turtles, which are caught as <a href="https://www.sciencedirect.com/science/article/pii/S0006320714003140">by-catch</a>.</p></li>
</ul>
<p>So how is illegal, unreported, and unregulated fishing connected to seafood fraud?</p>
<p>Seafood fraud allows this kind of fishing to flourish as illegal products are laundered through legitimate supply <a href="https://www.fao.org/documents/card/en/c/I8791EN/">chains</a>.</p>
<p>A recent <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2003741117">study</a> in the United States found when seafood is mislabelled, it is more likely to be substituted for a product from less healthy fisheries with management policies that are less likely to reduce the environmental impacts of fishing.</p>
<p>One <a href="https://usa.oceana.org/wp-content/uploads/sites/4/fraud_gap_report_final_6_6_16.pdf">review</a> of mislabelled seafood in the US found that out of 180 substituted species, 25 were considered threatened, endangered, or critically endangered by the International Union for Conservation of Nature and Natural Resources (IUCN).</p>
<p>Illegal fishing and seafood fraud also has a human cost. It can:</p>
<ul>
<li><p>adversely affect the livelihoods of law-abiding fishers and seafood <a href="https://www.sciencedirect.com/science/article/pii/B9780128015926000048">businesses</a></p></li>
<li><p>threaten food security</p></li>
<li><p>facilitate human rights abuses such as forced labour and <a href="https://link.springer.com/content/pdf/10.1007/978-3-030-32811-5_127-1.pdf">piracy</a> </p></li>
<li><p>increase risk of exposure to pathogens, drugs, and other banned substances in <a href="https://usa.oceana.org/wp-content/uploads/sites/4/fraud_gap_report_final_6_6_16.pdf">seafood</a>.</p></li>
</ul>
<h2>The chemical fingerprints in shells and bones</h2>
<p>A vast range of marine animals are harvested for food every year, including fish, molluscs, crustaceans, and <a href="https://www.fao.org/documents/card/en/c/ca9229en/">echinoderms</a>.</p>
<p>However, traditional food provenance methods are typically designed to identify one species at a time. </p>
<p>That might benefit the species and industry in question, but it is expensive and time consuming. As such, current methods are restricted to a relatively small number of species.</p>
<p>In our study, we described a broader, universal method to identify provenance and detect fraud. </p>
<p>How? We harnessed natural chemical markers imprinted in the shells and bones of marine animals. These markers reflect an animal’s environment and can identify where they are from.</p>
<p>We focused on a chemical marker that is similar across many different marine animals. This specific chemical marker, known as “oxygen isotopes”, is determined by ocean composition and temperature rather than an animal’s biology. </p>
<p>Exploiting this commonality and how it relates to the local environment, we constructed a global ocean map of oxygen isotopes that helps researchers understand where a marine animal may be from (by matching the oxygen isotope value in shells and bones to the oxygen isotope value in the map).</p>
<p>After rigorous testing, we demonstrated this global map (or “isoscape”) can be used to correctly identify the origins of a wide range of marine animals living in different latitudes. </p>
<p>For example, we saw up to 90% success in classifying fish, cephalopods, and shellfish between the tropical waters of Southeast Asia and the cooler waters of southern Australia.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Mussels lie on an ice bed at a shop." src="https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483430/original/file-20220908-19-s61mzf.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">Demand for seafood remains strong around the world.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/pile-of-fresh-mussels-on-white-surface-with-sour-lemons-6397652/">Photo by Julia Volk/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What next?</h2>
<p>Oxygen isotopes, as a universal marker, worked well on a range of animals collected from different latitudes and across broad geographic areas.</p>
<p>Our next step is to integrate oxygen isotopes with other universal chemical markers to gives clues on longitude and refine our approach.</p>
<p>Working out the provenance of seafood is a large and complex challenge. No single approach is a silver bullet for all species, fisheries or industries. </p>
<p>But our approach represents a step towards a more inclusive, global system for validating seafood provenance and fighting seafood fraud. </p>
<p>Hopefully, this will mean ensure fewer marine species are left behind and more consumer confidence in the products we buy.</p>
<p><em>Dr Jasmin Martino, a Postdoctoral Research Fellow at the Australian Nuclear Science and Technology Organisation, contributed to this research and article.</em></p><img src="https://counter.theconversation.com/content/189471/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zoe Doubleday receives funding from the Australian Research Council, Fisheries Research and Development Corporation, and the Australian Academy of Science.</span></em></p>Traditional food provenance methods are typically designed to identify one species at a time. So we worked out a new approach, as part of a broader effort to combat seafood fraud and illegal fishing.Zoe Doubleday, Marine Ecologist and ARC Future Fellow, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1840632022-08-09T03:58:15Z2022-08-09T03:58:15ZOnce the fish factories and ‘kidneys’ of colder seas, Australia’s decimated shellfish reefs are coming back<figure><img src="https://images.theconversation.com/files/468119/original/file-20220609-23-bh99c.jpg?ixlib=rb-1.1.0&rect=5%2C15%2C3493%2C2313&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Australia once had vast oyster and mussel reefs, which anchored marine ecosystems and provided a key food source for coastal First Nations people. But after colonisation, Europeans harvested them for their meat and shells and pushed oyster and mussel reefs almost to extinction. Because the damage was done early – and largely underwater – the destruction of these reefs was all but forgotten. </p>
<p>No longer. We have learned how to restore these vital reef systems. After a <a href="https://www.abc.net.au/news/2015-03-29/oysters-and-mussels-to-return-to-port-phillip-bay-research-plan/6356404">successful pilot</a> in 2015, there are now 46 shellfish reef restorations underway – Australia’s largest marine restoration program ever undertaken. It’s not a moment too soon. There’s just one natural reef remaining for the Australian flat oyster, which is teetering on extinction. </p>
<p>How did shellfish reefs go from forgotten to frontline? Our <a href="https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/cobi.13958">new research</a> shows how this historical amnesia was overcome through a national community of researchers, conservationists, and government and fisheries managers.</p>
<p>This matters, because oysters and mussels are <a href="https://theconversation.com/the-surprising-benefits-of-oysters-and-no-its-not-what-youre-thinking-90697#:%7E:text=Their%20filter%2Dfeeding%20improves%20water,and%20even%20soak%20up%20carbon.">ecological superheroes</a>. As we restore these reefs, we give local marine life a real boost and support human livelihoods reliant on healthy seas. These cold-water reefs play a similar role to coral in tropical seas. They give hiding places and food to baby fish, filter seawater and defend coastlines against erosion from waves. </p>
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<img alt="" src="https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=946&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=946&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=946&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1188&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1188&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468127/original/file-20220610-16526-8lsi1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1188&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">Large-scale shellfish reef restoration projects began with a single pilot in 2015 and soared to 46 projects nationwide by 2022.</span>
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<h2>What killed our original shellfish reefs?</h2>
<p>Just 200 years ago, shellfish reefs carpeted Australia’s temperate regions, filling up sheltered bays and estuaries around over 7,000 kilometres of coastline. </p>
<p><a href="https://www.nature.com/articles/s41467-022-29818-z">Archaeological research</a> from Queensland shows First Nations people were sustainably harvesting local shellfish reefs over at least 5,000 years, replenishing oyster populations by building reefs with stone and shell. </p>
<p>This ended as Europeans took the lands and waters from Traditional Owners. Shellfish became one of colonial Australia’s first fisheries. Oysters were fished extensively for food, while their shells were burnt to manufacture lime for fertiliser and cement. If you walk past a colonial-era building, look at the mortar. Chances are, a <a href="https://blogs.sydneylivingmuseums.com.au/cook/oyster-shells/">lot of oyster shells</a> went into it. </p>
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Read more:
<a href="https://theconversation.com/the-worlds-most-degraded-marine-ecosystem-could-be-about-to-make-a-comeback-110233">The world's most degraded marine ecosystem could be about to make a comeback</a>
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<p>Even though the wild fishery ended a century ago, these shellfish weren’t able to return. That’s because they can’t just grow on bare sand. Their preferred substrate is the shells of their ancestors, left behind on the sea bottom. Once substrate was scraped by dredge or smothered by sediment, there was nowhere for baby oysters and mussels to settle and grow. </p>
<p>Today, there’s just one small natural flat oyster reef (<em>Ostrea angasi</em>) and six remnant Sydney Rock oyster (<em>Saccostrea glomerata</em>) reefs remaining, across <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0190914">all Australian waters</a>. </p>
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<img alt="" src="https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468151/original/file-20220610-28309-o1wfy0.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">
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<span class="caption">Colonial oyster fishers used oyster dredges, rakes, and shovels to scrape oysters from the seafloor.</span>
<span class="attribution"><span class="source">State Library of South Australia</span></span>
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<h2>How to kick-start shellfish reef restoration</h2>
<p>Shellfish can’t recover by themselves. But it turns out with a little human help, they can. Think of it as making up for our unsustainable use.</p>
<p>For a decade before the first large-scale restoration, recreational fishing groups and community groups worked on smaller projects, sometimes with government backing. </p>
<p>To begin larger-scale restoration work, we first had to remember how it used to be.
Because the ecological collapse of Australia’s shellfish reefs was so profound, they were almost <a href="https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/cobi.12452">lost to human memory</a>. Historical records guided us as to what a restored ecosystem should look like, and where these reefs used to be.</p>
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<img alt="" src="https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=324&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=324&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=324&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=407&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=407&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468128/original/file-20220610-25216-oin2ra.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=407&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">Australia’s only surviving native flat oyster reef (Ostrea angasi) is in eastern Tasmania. Flat oyster reefs were dredged to obliteration over thousands of kilometres of southern Australian coastline.</span>
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<p>Our job was made easier because of the huge benefits shellfish reefs provide to marine life. Intact oyster and mussel reefs are natural fish factories providing nursery habitats for economically important fish species like bream and whiting. </p>
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Read more:
<a href="https://theconversation.com/the-surprising-benefits-of-oysters-and-no-its-not-what-youre-thinking-90697">The surprising benefits of oysters (and no, it's not what you're thinking)</a>
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<p>Even better, these filter-feeding shellfish are the kidneys of the coast, cleaning water cloudy with sediment or overloaded with nutrients. A single oyster can filter 100 litres of water a day. Shellfish reefs also act as living defences against the energy of waves, store carbon in their shells and help protect intertidal communities from the warming climate through shade and moisture at low tide. </p>
<p>People working on reef restoration turned to our thriving oyster and mussel farming industry to understand their life cycles and what they needed to thrive. The fact these farms are successful indicated many areas remained suitable for shellfish reefs. </p>
<p>Environmental NGO The Nature Conservancy connected the <a href="https://www.natureaustralia.org.au/what-we-do/our-priorities/oceans/ocean-stories/restoring-shellfish-reefs/">emerging reef restoration community</a> as well as bringing practical experience from longer-running shellfish restoration projects in America. Reef restoration work is now being led by conservation NGOs, local and state governments, and, increasingly, by community groups. </p>
<p>So does it work? Yes. It’s as if the oysters have been waiting for this opportunity. Many human-made reefs have been settled by millions of baby oysters within months of construction, such as the largest project to date, the 20 hectare <a href="https://theconversation.com/huge-restored-reef-aims-to-bring-south-australias-oysters-back-from-the-brink-77405">Windara Reef</a> in South Australia. Some restored reefs are closing in on oyster densities in line with natural reefs.</p>
<h2>Looking forward</h2>
<p>We hope the rapid rise of shellfish reef restoration is the beginning of a new era for large-scale marine restoration in Australia. </p>
<p>Today, community-led restorations are <a href="https://ozfish.org.au/projects/moreton-bay-shellfish-reef-restoration/">growing in scale</a> and number, and public support for shellfish restoration is widespread. </p>
<p>It is an impressive story. This is a national program of recovery showing significant successes with a relatively modest investment. These restoration efforts show large-scale action to repair nature can work – and work quickly – when experts from a range of disciplines work with communities towards a common goal. </p>
<p>As the restored oyster and mussel reefs mature, we will see more fish in our seas and more recreation and tourism opportunities emerging. That, in turn, could give more communities the idea to restore their own shellfish reefs. Together, we can bring back the reefs which lived in our cooler seas for millennia. </p>
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Read more:
<a href="https://theconversation.com/huge-restored-reef-aims-to-bring-south-australias-oysters-back-from-the-brink-77405">Huge restored reef aims to bring South Australia's oysters back from the brink</a>
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<p class="fine-print"><em><span>Dominic McAfee receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Christine Crawford receives funding from The Nature Conservancy for short-term contracts.</span></em></p><p class="fine-print"><em><span>Ian McLeod received funding from the National Environmental Science Program Marine Biodiversity Hub. </span></em></p><p class="fine-print"><em><span>Sean Connell receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Chris Gillies 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>Only 200 years ago, Australian waters were full of oyster and shellfish reefs. Then they collapsed. Now large scale restoration efforts are underway.Dominic McAfee, Postdoctoral researcher, marine ecology, University of AdelaideChris Gillies, Adjunct Associate Professor in marine ecology, James Cook UniversityChristine Crawford, Senior research fellow in marine biology, University of TasmaniaIan McLeod, Professorial Research Fellow in Marine Biology, James Cook UniversitySean Connell, Professor, Program Director of Stretton Institute, Program Director of Environment Insitute, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.