tag:theconversation.com,2011:/ca-fr/topics/marine-ecosystems-1626/articlesMarine ecosystems – La Conversation2024-03-25T13:05:19Ztag:theconversation.com,2011:article/2242812024-03-25T13:05:19Z2024-03-25T13:05:19ZAttaching seaweed spores to used scallop shells could restore UK’s coastal kelp forests<figure><img src="https://images.theconversation.com/files/583221/original/file-20240320-16-8972yw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Marine biologists are collecting spores from healthy kelp forests to help restore coastal habitats. </span> <span class="attribution"><span class="source">Marine Biological Association 2024</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Kelp spores are being seeded and grown on small rocks and scallop shells – a seafood waste product – in efforts to regenerate the UK’s coastal kelp forests. </p>
<p>Unlike many other restoration techniques, this method is cheap and easy to carry out. There’s no need for expensive, labour-intensive dive teams to install kelp onto the seabed. </p>
<p>Once gravel or shells have been seeded with kelp in aquariums, teams can simply drop them over the side of a boat where they sink, allowing the kelp to attach to the seabed where it grows to maturity. This is <a href="https://www.nature.com/articles/s41598-020-60553-x">as effective</a> as hand-deployment by divers and far more economical. </p>
<p>Our team of marine scientists is working with the Fishmongers’ Company’s Charitable Trust and the Kelp Conservation Initiative to develop this “green gravel” approach. First pioneered in <a href="https://www.nature.com/articles/s41598-020-60553-x">Norway</a>, green gravel techniques have previously been tested on wave-exposed shores along the north-east <a href="https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/an-assessment-of-the-utility-of-green-gravel-as-a-kelp-restoration-tool-in-waveexposed-intertidal-habitats/3F3671DD02E494988C31E1CF8360F11E">coast of the UK</a>. </p>
<p>Now, in the lab, we are trialling waste scallop shells from the seafood industry and different types of stone from around the UK, easily sourced from hardware stores, as the basis for growing four types of native kelp. Every year, more than <a href="https://www.uclan.ac.uk/articles/research/blackpool-seashell-concrete#:%7E:text=Nationally%20around%2030%2C000%20tonnes%20of,around%2065%20blue%20whales.%E2%80%9D">30,000 tonnes</a> of shells go to landfill in the UK, at a cost to the industry. There’s huge potential to use shells as a restoration material at scale, either whole or crushed into smaller pieces.</p>
<h2>From tanks to seabed trials</h2>
<p>We begin <a href="https://www.nature.com/articles/s41598-020-60553-x">green gravel</a> restoration by identifying a healthy wild population of kelp with adult plants that can be used as donors. Sections of frond filled with spores are cut out and bought back to the lab, then disinfected with a quick dip in iodine solution. </p>
<p>Gravel or scallop shells are cleaned and put into tanks of seawater. The fertile kelp material is dried out overnight then rehydrated to initiate the release of hundreds of millions of microscopic kelp spores. Once extracted, spores are added to tanks of seawater where they settle to seed the gravel or shells.</p>
<p>Spores develop quickly, so tiny kelp seedlings are visible as a brown fuzz within three to four weeks. We monitor growth for three months, then once the kelp plants reach 1cm long, the gravel or shells are taken by boat to test sites off the coasts of Newcastle, Cornwall and Devon. Once dropped over the side of the boat, the stones or shells quickly sink. Over time, the seaweed’s root-like “holdfast” grows to attach securely to the seabed beneath.</p>
<p>By monitoring the growth of these kelp habitats, ideally every few months for several years, we can measure the success of this restoration method. Our early results suggest that a wide variety of UK stone types will be suitable, although success is likely to vary due to local conditions at each site.</p>
<h2>Why restore kelp forests?</h2>
<p>Found along <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780128050521000036">almost a third</a> of the world’s coastlines, kelp are marine algae that can form diverse ecosystems, like forests on land. People depend on the <a href="https://www.nature.com/articles/s41467-023-37385-0">valuable goods and services</a> they provide – from shelter for commercially valuable fish to carbon storage and coastal protection. </p>
<p>But these forests are threatened by warming oceans and marine heatwaves, pollution, poor water quality and overfishing. In many areas, kelp forests are <a href="https://www.pnas.org/doi/full/10.1073/pnas.1606102113">shrinking or have been lost</a> leading to <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/aqc.3880">calls for restoration action</a>. </p>
<p>Seven kelp species, together with other brown seaweeds, cover an area of up to <a href="https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/distribution-and-environmental-requirements-of-large-brown-seaweeds-in-the-british-isles/31A839DE1DE55AFFDD5C0595882A8CEA">20,000 km²</a> along the UK’s rugged coastline. Local declines have been reported in certain areas, including <a href="https://www.frontiersin.org/articles/10.3389/fevo.2022.642775/full">west Sussex</a> and county Durham. </p>
<p>UK kelp forests are not exempt from the impacts of climate change and human activities. Early warning signs include species range shifts, with cold-adapted kelp species <a href="https://www.cambridge.org/core/services/aop-cambridge-core/content/view/5B2FD351846D2144E5D11D02EB7B58BB/S0025315405012506a.pdf/div-class-title-using-historical-data-to-detect-temporal-changes-in-the-abundances-of-intertidal-species-on-irish-shores-div.pdf">declining in southern England</a>, while <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2745.13053">warm-adapted species are expanding</a> and taking take their place. These changes have knock-on effects in terms of how these ecosystems work, for example in the amount and quality of habitat that they provide for <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.13053">other species</a>. </p>
<p>Restoration has been hailed as a tool to regenerate kelp forests in areas where they are shrinking or have been lost, with an <a href="https://kelpforestalliance.com/TNC-KFA-Kelp-Guidebook-2022.pdf">array of techniques</a> being developed around the world.</p>
<p>Almost 200 nations have pledged to protect <a href="https://www.unep.org/resources/kunming-montreal-global-biodiversity-framework">30% of the world’s oceans</a> by 2030, while the <a href="https://link.springer.com/article/10.1007/s10811-023-03103-y">kelp forest challenge</a> – a global initiative run by the Kelp Forest Alliance – aims to protect 4 million hectares of kelp forest by 2040.</p>
<p>But the <a href="https://plymsea.ac.uk/id/eprint/10160/">UK lags behind</a> on the international marine restoration stage, having only recently made limited progress towards restoring seagrass meadows, saltmarshes, oyster reefs and kelp beds.</p>
<p>Our progress over the next three years will inform kelp restoration methods through the <a href="https://www.greengravel.org/action-group">Green Gravel Action Group</a> which recently identified <a href="https://www.frontiersin.org/articles/10.3389/fmars.2024.1364263/abstract">international challenges and solutions</a> to marine forest restoration. Our team is working out how best to adapt green gravel methods to specific locations and wave conditions in the UK. </p>
<p>If scalable and effective in different scenarios, this technique could provide a sustainable use for waste shells, reducing the volume sent to landfill each year nationally, while restoring crucial ocean habitats.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Kelp seaweed spores are being grown on small rocks and waste scallop shells as part of a trial exploring how to regenerate the UK’s coastal kelp forests.Catherine Wilding, Senior Research Assistant, Marine Ecology, Marine Biological AssociationHannah Earp, Postdoctoral Research Associate, Marine Ecology, Newcastle UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2233382024-03-07T23:22:41Z2024-03-07T23:22:41ZThe Southern Ocean upwelling is a mecca for whales and tuna that’s worth celebrating and protecting<figure><img src="https://images.theconversation.com/files/580331/original/file-20240307-26-4bgm4.jpg?ixlib=rb-1.1.0&rect=18%2C0%2C2061%2C1400&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://animalia.bio/blue-whale">NOAA Photo Library/Animalia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>The Great Southern Australian Coastal Upwelling System is an upward current of water over vast distances along Australia’s southern coast. It brings nutrients from deeper waters to the surface. This nutrient-rich water supports a rich ecosystem that attracts iconic species like the southern bluefin tuna (<em>Thunnus maccoyii</em>) and blue whale (<em>Balaenoptera musculus brevicauda</em>). </p>
<p>The environmental importance of the upwelling is one reason the federal government this week <a href="https://www.abc.net.au/news/2024-03-06/southern-ocean-offshore-wind-zone-declared/103552016">declared a much-reduced zone</a> for offshore wind turbines in the region. The zone covers <a href="https://www.dcceew.gov.au/energy/renewable/offshore-wind/areas/southern-ocean-region">one-fifth of the area</a> originally proposed.</p>
<p>This year marks the 20th anniversary of a <a href="https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003GL019221">research publication</a> that revealed the existence of the large seasonal upwelling system along Australia’s southern coastal shelves. Based on over 20 years of scientific study, we can now answer many critical questions. </p>
<p>How does this upwelling work? How can it be identified? Which marine species benefit from the upwelling? Does the changing climate affect the system?</p>
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Read more:
<a href="https://theconversation.com/australia-is-poised-to-be-a-world-leader-in-offshore-wind-but-any-potential-risks-to-marine-life-remain-poorly-regulated-193212">Australia is poised to be a world leader in offshore wind, but any potential risks to marine life remain poorly regulated</a>
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<h2>Where do the nutrients come from?</h2>
<p>Sunlight does not reach far into the sea. Only the upper 50 metres of the water column receives enough light to support the microscopic phytoplankton – single-celled organisms that depend on photosynthesis. This is the process of using light energy to make a simple sugar, which phytoplankton and plants use as their food.</p>
<p>As well as light, the process requires a suite of nutrients including nitrogen and phosphorus. </p>
<p>Normally, the sunlight zone of the oceans is low in nitrogen. Waters deeper than 100m contain high levels of it. This deep zone of high nutrient levels is due to the presence of bacteria that decompose sinking particles of dead organic matter. </p>
<p>Upwelling returns nutrient-rich water to the sunlight zone where it fuels rapid phytoplankton growth. Phytoplankton production is the foundation of a productive marine food web. The phytoplankton provides food for zooplankton (tiny floating animals), small fish and, in turn, predators including larger fish, marine mammals and seabirds. </p>
<p>The annual migration patterns of species such as tuna and whales match the timing and location of upwelling events.</p>
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Read more:
<a href="https://theconversation.com/australian-endangered-species-southern-bluefin-tuna-11636">Australian endangered species: Southern Bluefin Tuna</a>
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<h2>What causes the upwelling?</h2>
<p>In summer, north-easterly coastal winds cause the upwelling. These winds force near-surface water offshore, which draws up deeper, nutrient-enriched water to replace it in the sunlight zone. </p>
<p>The summer winds also produce a swift coastal current, called an upwelling jet. It flows northward along Tasmania’s west coast and then turns westward along Australia’s southern shelves.</p>
<p>Satellites can detect the areas of colder water brought to the sea surface. Changes in the colour of surface water as a result of phytoplankton blooms can also be detected. This change is due to the presence of chlorophyll-a, the green pigment of phytoplankton. </p>
<p>From satellite data, we know the upwelling occurs along the coast of South Australia and western Victoria. It’s strongest along the southern headland of the Eyre Peninsula and shallower waters of the adjacent Lincoln Shelf, the south-west coast of Kangaroo Island, and the Bonney Coast. The <a href="https://www.publish.csiro.au/mf/MF9810843">Bonney upwelling</a>, now specifically <a href="https://www.dcceew.gov.au/energy/renewable/offshore-wind/areas/southern-ocean-region">excluded from the new wind farm zone</a>, was first described in the early 1980s. </p>
<p>Coastal upwelling driven by southerly winds also forms occasionally along Tasmania’s west coast.</p>
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<a href="https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=523&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=523&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=523&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=658&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=658&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580315/original/file-20240307-20-sgqybm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=658&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">Satellites can detect the phytoplankton blooms resulting from the upwelling along Australia’s southern coastline.</span>
<span class="attribution"><span class="source">Author provided</span></span>
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<p>Coastal wind events favourable for upwelling occur regularly during summer. However, their timing and intensity is highly variable. </p>
<p>On average, most upwelling events along Australia’s southern shelves occur in February and March. In some years strong upwelling can begin as early as November. </p>
<p><a href="https://doi.org/10.1016/j.oceano.2022.12.003">Recent research</a> suggests the overall upwelling intensity has not dramatically changed in the past 20 years. The findings indicate global climate changes of the past 20 years had little or no impact on the ecosystem functioning.</p>
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Read more:
<a href="https://theconversation.com/torrents-of-antarctic-meltwater-are-slowing-the-currents-that-drive-our-vital-ocean-overturning-and-threaten-its-collapse-202108">Torrents of Antarctic meltwater are slowing the currents that drive our vital ocean 'overturning' – and threaten its collapse</a>
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<h2>What are the links between upwelling, tuna and whales?</h2>
<p>The Great Southern Australian Coastal Upwelling System features two keystone species – the ecosystem depends on them. They are the Australian sardine (<em>Sardinops sagax</em>) and the Australian krill (<em>Nyctiphanes australis</em>), a small, shrimp-like creature that’s common in the seas around Tasmania. </p>
<p>Sardines are the key diet of larger fish, including the southern bluefin tuna, and various marine mammals including the Australian sea lion (<em>Neophoca cinerea</em>). Phytoplankton and krill are the key food source for baleen whales. They include the <a href="https://doi.org/10.47536/jcrm.v4i2.854">blue whales</a> that come to Australia’s southern shelves to feed during the upwelling season. </p>
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Read more:
<a href="https://theconversation.com/why-scientists-need-your-help-to-spot-blue-whales-off-australias-east-coast-164620">Why scientists need your help to spot blue whales off Australia’s east coast</a>
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<p>Unlike phytoplankton and many zooplankton species that live for only weeks to months, krill has a lifespan of several years. It does not reach maturity during a single upwelling season. It’s most likely the coastal upwelling jet transports swarms of mature krill from the waters west of Tasmania north-westward into the upwelling region. </p>
<p>So the whales seem to benefit from two distinct features of the upwelling: its phytoplankton production and the krill load imported by the upwelling jet.</p>
<p>Seasonal phytoplankton blooms along Australia’s southern shelves are much weaker than other <a href="https://link.springer.com/book/10.1007/978-3-319-42524-5">large coastal upwelling systems</a> such as the <a href="https://oceantracks.org/library/the-north-pacific-ocean/upwelling-and-the-california-current">California current</a>. Nonetheless, their timing and location appear to fit perfectly into the annual migration patterns of southern bluefin tuna and blue whales, creating a natural wonder in the southern hemisphere.</p><img src="https://counter.theconversation.com/content/223338/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jochen Kaempf 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>This marine ecosystem is so important it’s one of the main reasons the federal government has greatly reduced the area available for offshore wind farms in the region.Jochen Kaempf, Associate Professor of Natural Sciences (Oceanography), Flinders UniversityLicensed 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>
<figure class="align-center zoomable">
<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>
<figcaption>
<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>
</figcaption>
</figure>
<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>
<figure class="align-center zoomable">
<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>
<figcaption>
<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>
</figcaption>
</figure>
<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>
<hr>
<p>
<em>
<strong>
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>
</strong>
</em>
</p>
<hr>
<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/2126902023-11-02T19:12:25Z2023-11-02T19:12:25ZTaming wild northern rivers could harm marine fisheries and threaten endangered sawfish<figure><img src="https://images.theconversation.com/files/556797/original/file-20231031-23-pl3bb0.JPG?ixlib=rb-1.1.0&rect=26%2C0%2C2198%2C1504&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Google Earth Image Landsat/Copernicus</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Australia’s tropical northern rivers still run wild and free. These relatively pristine areas have so far avoided extensive development. But this might not last. There are <a href="https://www.dcceew.gov.au/water/policy/national/northern-australia">ongoing scoping studies exploring irrigating agricultural land</a> using water from these rivers.</p>
<p>Our <a href="https://www.nature.com/articles/s41893-023-01238-x">new research</a> in the journal Nature Sustainability shows disturbing the delicate water balance upstream can have major consequences downstream, even hundreds of kilometres away.</p>
<p>Using our latest computer modelling, we found northern water resource development would have substantial effects on prawn, mud crab and barramundi fisheries in the Gulf of Carpentaria. These are valuable Australian marine fisheries which depend on healthy estuaries. Reducing river flows would also disturb mangrove and seagrass habitats and threaten the iconic endangered largetooth sawfish.</p>
<p>Freshwater flows to the sea play a crucial role, boosting the productivity of marine, estuarine and freshwater systems. These complex interactions must be carefully considered in the assessment of future development plans.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic illustrating how altering river flow influences downstream estuarine and marine species and habitats" src="https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Changing the natural river flow regime has consequences for estuarine and marine species and fisheries.</span>
<span class="attribution"><span class="source">James Chen in Plaganyi et al (2023) Nature Sustainability</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-we-protect-mangroves-we-protect-our-fisheries-our-towns-and-ourselves-214390">If we protect mangroves, we protect our fisheries, our towns and ourselves</a>
</strong>
</em>
</p>
<hr>
<h2>Rivers are our lifeblood</h2>
<p>Worldwide, few wild running rivers remain. Their future is uncertain given <a href="https://turningthetide.watercommission.org/">growing demand for water</a>. </p>
<p>Climate change is putting extra pressure on rivers as temperatures rise, rainfall patterns shift and <a href="https://theconversation.com/marine-heatwaves-are-getting-hotter-lasting-longer-and-doing-more-damage-95637">extreme events</a> become more frequent. </p>
<p>Rivers are the lifeblood of ecosystems and communities. They connect land, estuaries and the sea. But assessments of river developments <a href="https://www.science.org/doi/epdf/10.1126/science.abj4017">often focus narrowly on local effects</a>. They ignore the fact downstream estuaries and marine systems depend on freshwater flows. Few studies have calculated the costs of upstream catchment developments to downstream estuarine and marine ecosystems and fisheries.</p>
<p>We must avoid the <a href="https://theconversation.com/damming-northern-australia-we-need-to-learn-hard-lessons-from-the-south-53885">mistakes made in southern Australia</a> where <a href="https://theconversation.com/excessive-water-extractions-not-climate-change-are-most-to-blame-for-the-darling-river-drying-192621">too much water has been taken out of the system</a> for growing crops. That means carefully evaluating the design of dams or irrigation schemes, considering when, where and how much water should be taken – and the likely trade-offs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing many common banana prawns on a trawler. This is one of several species caught by the Northern Prawn Fishery" src="https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Yields of common banana prawn vary depending on river flows from multiple catchments.</span>
<span class="attribution"><span class="source">NPF Industry Pty Ltd, Australian Council of Prawn Fisheries Ltd, Austral Fisheries and Raptis Seafoods</span></span>
</figcaption>
</figure>
<h2>Why should we care about northern rivers?</h2>
<p>Australia’s remote northern rivers are one of the last strongholds for endangered species such as the <a href="https://theconversation.com/australian-endangered-species-largetooth-sawfish-24558">largetooth sawfish</a>. These iconic species are born in estuaries before spending their first few years of life upstream in freshwater rivers. </p>
<p>Flows from these rivers also sustain extensive mangrove forests and seagrass beds. Periodic floods <a href="https://www.abc.net.au/news/2020-10-30/barramundi-banana-prawns-could-be-threatened-gulf-of-carpentaria/12828280">boost the food supply</a> for many prized marine fisheries such as prawns, barramundi and <a href="https://tinyurl.com/2haudz3t">mud crabs</a>.</p>
<p>The rivers also have <a href="https://indigenousknowledge.unimelb.edu.au/curriculum/resources/indigenous-voices-in-water">cultural significance</a> for Aboriginal people and represent a valuable resource, providing food and supporting livelihoods. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of an endangered largetooth sawfish in shallow water" src="https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Endangered largetooth sawfish are sensitive to changes in river flows.</span>
<span class="attribution"><span class="source">Rich Pillans/CSIRO</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/an-el-nino-hit-this-banana-prawn-fishery-hard-heres-what-we-can-learn-from-their-experience-139852">An El Niño hit this banana prawn fishery hard. Here’s what we can learn from their experience</a>
</strong>
</em>
</p>
<hr>
<h2>Using modelling to connect rivers, estuaries and oceans</h2>
<p>We coupled CSIRO’s sophisticated <a href="https://www.csiro.au/en/showcase/nawra">river models</a> with our <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-2979.2012.00488.x">specially tailored ecosystem models</a> to represent how altering river flows may influence the downstream ecology and fishery yields. </p>
<p>We used catch data from fisheries to analyse how past natural changes in flow influenced catch rates. This was combined with extensive previous research on the biology and ecology of each species to model the dynamics of catchment-to-coast systems. We were particularly interested in the natural life cycles of fish and crustaceans in our unique northern wet-dry tropical rivers and estuaries. We then simulated multiple water resource development scenarios to assess and compare various impacts and ways to reduce them. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two column charts showing risk to key populations and fisheries in the Gulf of Carpentaria from changes in freshwater flows." src="https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=562&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=562&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=562&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=707&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=707&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=707&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">We quantified risk to key populations and fisheries in the Gulf of Carpentaria from changes in freshwater flows due to various hypothetical water resource developments (WRD).</span>
<span class="attribution"><span class="source">Plagányi et al. (2023) Nature Sustainability</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>For <a href="https://tinyurl.com/2haudz3t">mud crabs, we linked river flow</a> and other climate drivers to their life cycle and were able to show how past changes in flow could explain the past variation in crab catch, particularly for rivers in which flow was seasonally variable. We could then use this model to predict how crab catch and abundance might change in the future, depending on how much water is removed from rivers and the method of removal.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial image of an estuary feeding into the Gulf of Carpentaria" src="https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.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">Rivers connect land, estuaries and the sea. Large estuaries feed into the Gulf of Carpentaria.</span>
<span class="attribution"><span class="source">Queensland Department of Agriculture and Fisheries</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-industry-lines-up-to-take-water-from-a-wild-top-end-river-trees-tell-the-story-of-a-much-drier-past-177221">As industry lines up to take water from a wild Top End river, trees tell the story of a much drier past</a>
</strong>
</em>
</p>
<hr>
<h2>Integrated management from catchment to coast</h2>
<p>Our research shows freshwater flows to the sea are crucial for environmentally and economically important species. Any plan to dam or extract freshwater from Australia’s last wild rivers should account for these effects.</p>
<p>Coupling scientific knowledge about marine and freshwater ecosystems with catchment development will improve infrastructure planning and flow management.</p>
<p>This is vital on a dry continent already <a href="https://theconversation.com/extreme-weather-caused-by-climate-change-has-damaged-45-of-australias-coastal-habitat-120671">challenged by climate change</a>. Every drop counts.</p>
<p><em>The authors wish to acknowledge Annie Jarrett, Chief Executive Officer of NPF Industry Pty Ltd, which represents Northern Prawn Fishery operators, for her contribution to the research.</em></p><img src="https://counter.theconversation.com/content/212690/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Éva Plagányi acknowledges Annie Jarrett, Chief Executive Officer of NPF Industry Pty Ltd, which represents Northern Prawn Fishery operators, for her contribution to the research.
Éva works for CSIRO and receives research funding from several sources, including the Fisheries Research and Development Corporation (FRDC) and the Australian Fisheries Management Authority (AFMA).
2018-079 Ecological modelling of the impacts of water development in the Gulf of Carpentaria with particular reference to impacts on the NPF was supported by funding from the Fisheries Research and Development Corporation on behalf of the Australian Government</span></em></p><p class="fine-print"><em><span>Laura Blamey works for CSIRO, which receives research funding from several source, including the Fisheries Research and Development Corporation (FRDC) and the Australian Fisheries Management Authority (AFMA).</span></em></p><p class="fine-print"><em><span>Michele Burford works for the Australian Rivers Institute, Griffith University and receives funding from several sources, including the National Environmental Science Program (NESP).</span></em></p><p class="fine-print"><em><span>Robert Kenyon works CSIRO, an organisation that receives research funding from several sources, including the Fisheries Research and Development Corporation (FRDC) and the Australian Fisheries Management Authority (AFMA).</span></em></p>Any plan to dam or extract water from some of Australia’s last wild rivers must carefully consider the consequences. Prawn, mud crab and barramundi fisheries could suffer in the Gulf of Carpentaria.Éva Plagányi, Senior Principal Research Scientist, CSIROLaura Blamey, Senior Research Scientist, CSIROMichele Burford, Professor - Australian Rivers Institute, and Dean - Research Infrastructure, Griffith UniversityRobert Kenyon, Marine Ecologist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2145982023-10-30T16:16:45Z2023-10-30T16:16:45ZNiger delta is rich in resources, but environmental destruction is pushing people into poverty<p>Nigeria’s Niger Delta region is rich in natural resources. Its <a href="https://www.researchgate.net/publication/284727294_Review_of_Ecological_Effects_of_Oil_Exploration_in_the_Niger-Delta_Nigeria">vast oil and gas deposits</a> are the mainstay of the country’s economy. </p>
<p>The region, in the southernmost part of the country, features coastal barrier islands, mangroves, freshwater swamp forests and lowland rain forests. The coast offers various ways of making a living, like fishing, tourism, producing salt, and farming coconut and bananas. </p>
<p>Yet it is estimated that over 47% of the population in the region <a href="https://beamexchange.org/uploads/filer_public/73/ff/73ffbabd-2447-4924-8a85-0a43f6f266dc/made-nigeria-poverty-assessment-report-final_compressed.pdf#page=4">lives</a> below the poverty line. </p>
<p>We study the economic aspects of environmental issues, and in a recent <a href="https://www.researchgate.net/profile/Otekenari-Elisha/publication/353741948_DESTRUCTION_OF_COASTAL_ECOSYSTEMS_AND_THE_VICIOUS_CYCLE_OF_POVERTY_IN_NIGER_DELTA_REGION/links/610d9423169a1a0103e569f4/DESTRUCTION-OF-COASTAL-ECOSYSTEMS-AND-THE-VICIOUS-CYCLE-OF-POVERTY-IN-NIGER-DELTA-REGION.pdf">paper</a> set out to understand the relationship between the destruction of coastal ecosystems in this region and the economic hardship the people faced.</p>
<p>We found that marine ecosystems had been badly affected by a number of factors, including an increasing population, pollution, over-fishing, damaging fishing techniques and global warming.</p>
<p>The degradation of the environment affects the poor the most as they depend on natural resources like seafood and wood for survival and energy. And they do not earn enough to relocate from polluted areas. </p>
<h2>The destruction of an ecosystem</h2>
<p>We identified a few areas where the Niger Delta ecosystem had been badly affected. The environmental problems in communities like Bille, Andoni, Okirika, Emohua and Ibaa in Rivers State are caused by oil spills, gas flaring, human activities and water pollution, among others. </p>
<p>Between 1976 and 2006, there were at least <a href="http://large.stanford.edu/courses/2017/ph240/nwagbo1/">7,000 oil spills</a> in the region, affecting an area of more than 2,500 square kilometres. These oil spills have polluted the soil, water and air, and they have had a <a href="https://www.aljazeera.com/features/2022/9/9/niger-delta-oil-spills-bring-poverty-low-crop-yields-to-farmers">devastating impact</a> on the people who live in the region. The destruction of the ecosystem has led to environmental problems like flooding and soil erosion, which destroys homes and crops, leading to further poverty. The lack of a healthy ecosystem has led to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0013935121000190#:%7E:text=Lung%20and%20skin%20cancers%20are,et%20al.%2C%202015">health problems</a> for the people living in the region. </p>
<p>Gas flaring is the process of burning off excess natural gas that is produced during oil drilling. More than 2.5 billion cubic feet of natural gas are <a href="https://www.amisdelaterre.org/wp-content/uploads/2019/10/gas-flaring-nigeria.pdf#page=4">flared</a> every day in the Niger Delta. This process <a href="https://www.iea.org/energy-system/fossil-fuels/gas-flaring">emits greenhouse gases</a> and other pollutants into the atmosphere, and it also wastes a valuable resource that could be used to generate electricity or heat homes.</p>
<p>Mangroves are being lost <a href="https://www.researchgate.net/profile/Otekenari-Elisha/publication/366371709_Asian_Journal_of_Current_Research_COMMUNITY-BASED_INTERVENTION_IN_THE_CONTROL_OF_ARTISANAL_REFINING_AGAINST_THE_ENVIRONMENT_IN_NIGER_DELTA_REGION_NIGERIA/links/639d793e095a6a77743755d0/Asian-Journal-of-Current-Research-COMMUNITY-BASED-INTERVENTION-IN-THE-CONTROL-OF-ARTISANAL-REFINING-AGAINST-THE-ENVIRONMENT-IN-NIGER-DELTA-REGION-NIGERIA.pdf#page=8">because of water pollution</a>. Mangrove forests are an important source of food and income for local communities, and their loss has led to a decline in fish stocks and other marine resources. This has damaged the livelihoods of fishers and increased the price of fish in local markets. </p>
<p>The environmental consequences of the destruction of mangroves include erosion and increased vulnerability to storms and flooding.</p>
<p>Natural resources such as nutrient-rich soil, water, trees and fossil fuels abound in marine ecosystems. Excessive exploitation of these resources through mining, logging and oil drilling has had a negative impact.</p>
<p>Animals in an ecosystem keep the food chain in balance. Due to overfishing and hunting, many animals are disappearing from the Niger Delta. Manatees, sea turtles, dolphins, monkeys, antelope and others are under threat. </p>
<p>The destruction of the ecosystem in the Niger Delta has led to a cycle of poverty:</p>
<ul>
<li><p>depletion of resources means people can’t make a living</p></li>
<li><p>environmental problems like flooding and soil erosion destroy homes and crops</p></li>
<li><p>human health depends on a healthy ecosystem.</p></li>
</ul>
<p>There is <a href="https://www.es.amnesty.org/fileadmin/noticias/Niger_Delta_Campaign_Digest_01.pdf">evidence</a> that destruction of the ecosystem has led to poverty in the Niger Delta region. Increasing soil sterility and diminishing agricultural output have <a href="https://www.researchgate.net/profile/Otekenari-Elisha/publication/353741948_DESTRUCTION_OF_COASTAL_ECOSYSTEMS_AND_THE_VICIOUS_CYCLE_OF_POVERTY_IN_NIGER_DELTA_REGION/links/610d9423169a1a0103e569f4/DESTRUCTION-OF-COASTAL-ECOSYSTEMS-AND-THE-VICIOUS-CYCLE-OF-POVERTY-IN-NIGER-DELTA-REGION.pdf#page=10">forced</a> farmers to move or seek illicit sources of living. The degradation of traditional fishing grounds has worsened hunger and poverty in fishing communities.</p>
<h2>Protecting and restoring ecosystems</h2>
<p>The impact of environmental degradation will only worsen if nothing is done to protect and restore degraded ecosystems.</p>
<p>In our paper we made the following suggestions.</p>
<ul>
<li><p>Regulate human activities: Fishing and hunting in the region should be controlled to prevent the depletion of fish and wildlife. Industrial activities, such as oil drilling and shipping, should also be regulated to prevent further pollution of the air, water and soil.</p></li>
<li><p>Restore degraded ecosystems: Mangrove forests can be replanted in areas where they have been destroyed. Another example is restoring wildlife populations through captive breeding programmes and releasing animals back into their natural habitats.</p></li>
<li><p>Build the capacity of local communities to manage their natural resources: This is essential for the long-term protection of the region. One example is providing training to community members on sustainable fishing and hunting practices. Another example is giving local communities a say in how their natural resources are managed.</p></li>
<li><p>Establish marine protected areas: This would help to conserve marine life and ensure that coastal communities can continue to benefit from the resources they depend on. One example is the Calabar-Oron Marine Protected Area in Cross River and Akwa Ibom states. It is home to a variety of marine life, including dolphins, turtles and whales. The area is used for sustainable fishing, ecotourism and research.</p></li>
</ul>
<p>We also recommend steps to address the root causes of poverty and inequality.</p>
<ul>
<li><p>Provide access to quality education and healthcare: Education can help to create greater awareness about environmental issues, and lead to economic opportunities. Availability of these social services could reduce the appeal of rebel groups that promise economic and social benefits.</p></li>
<li><p>Address marginalisation: Groups like women and ethnic minorities can be given equal access to resources and opportunities through inclusive decision-making at the local, state and national levels. Development programmes should target their specific needs. </p></li>
</ul>
<p>Finally, renewed efforts should be made to address conflict and insecurity in the Niger Delta by strengthening governance and the rule of law. Improved governance can lead to stronger enforcement of environmental laws and regulations, which can protect ecosystems from further degradation. In addition, it can protect land rights and create a more stable environment that offers economic opportunities.</p><img src="https://counter.theconversation.com/content/214598/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Otekenari David Elisha 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>Environmental degradation of Nigeria’s Niger Delta region is causing poverty as well as food insecurity, increased crime and conflict.Otekenari David Elisha, Environmental Economist, Ignatius Ajuru University of Education Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2155292023-10-17T19:08:11Z2023-10-17T19:08:11ZMore than 200 scientists from 19 countries want to tell us the Southern Ocean is in trouble<figure><img src="https://images.theconversation.com/files/554159/original/file-20231017-15-ht1j0s.jpg?ixlib=rb-1.1.0&rect=28%2C4%2C3155%2C2110&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Pat James, Australian Antarctic Division</span></span></figcaption></figure><p>While the Southern Ocean around Antarctica has been <a href="https://theconversation.com/the-southern-ocean-absorbs-more-heat-than-any-other-ocean-on-earth-and-the-impacts-will-be-felt-for-generations-189561">warming for decades</a>, the annual extent of winter sea ice seemed relatively stable – compared to the Arctic. In some areas Antarctic sea ice was even increasing. </p>
<p>That was until 2016, when <a href="https://www.nature.com/articles/s43247-023-00961-9">everything changed</a>. The annual extent of winter sea ice stopped increasing. Now we have had <a href="https://theconversation.com/devastatingly-low-antarctic-sea-ice-may-be-the-new-abnormal-study-warns-212376">two years of record lows</a>.</p>
<p>In 2018 the international scientific community agreed to produce the first marine ecosystem assessment for the Southern Ocean. We modelled the assessment process on a working group of the Intergovernmental Panel on Climate Change (IPCC). So the resulting “<a href="https://zenodo.org/records/8359585">summary for policymakers</a>” being released today is like an IPCC report for the Southern Ocean. </p>
<p>This report can now be used to guide decision-making for the protection and conservation of this vital region and the diversity of life it contains. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing the number of authors from different regions, illustrating the international nature of the assessment process." src="https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=271&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=271&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=271&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=341&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=341&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554187/original/file-20231017-2786-gzvb0u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=341&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Global participation (numbers of authors from different regions) in the assessment.</span>
<span class="attribution"><a class="source" href="https://zenodo.org/records/8359585">Constable, A.J. et al (2023) Marine Ecosystem Assessment for the Southern Ocean.</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fractured-foundations-how-antarcticas-landfast-ice-is-dwindling-and-why-thats-bad-news-207814">Fractured foundations: how Antarctica's 'landfast' ice is dwindling and why that's bad news</a>
</strong>
</em>
</p>
<hr>
<h2>Why should we care about sea ice?</h2>
<p>Sea ice is to life in the Southern Ocean as soil is to a forest. It is the foundation for Antarctic marine ecosystems.</p>
<p>Less sea ice is a danger to all wildlife – from krill to emperor penguins and whales.</p>
<p>The sea ice zone provides essential food and safe-keeping to young Antarctic krill and small fish, and seeds the expansive growth of phytoplankton in spring, nourishing the entire food web. It is a platform upon which penguins breed, seals rest, and around which whales feed. </p>
<p>The international bodies that manage Antarctica and the Southern Ocean under the <a href="https://www.ats.aq/index_e.html">Antarctic Treaty System</a> urgently need better information on marine ecosystems. Our report helps fill this gap by systematically identifying options for managers to maximise the resilience of Southern Ocean ecosystems in a changing world.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1705569410604314758"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/emperor-penguins-face-a-bleak-future-but-some-colonies-will-do-better-than-others-in-diverse-sea-ice-conditions-214625">Emperor penguins face a bleak future – but some colonies will do better than others in diverse sea-ice conditions</a>
</strong>
</em>
</p>
<hr>
<h2>An open and collaborative process</h2>
<p>We sought input from a wide range of people across the entire Southern Ocean science community. </p>
<p>We sought to answer questions about the state of the whole Southern Ocean system - with an eye on the past, present and future.</p>
<p>Our team comprised 205 authors from 19 countries. They authored <a href="https://www.frontiersin.org/research-topics/10606/marine-ecosystem-assessment-for-the-southern-ocean-meeting-the-challenge-for-conserving-earth-ecosystems-in-the-long-term#overview">24 peer-reviewed papers</a>. We then distilled the findings from these papers into our summmary for policymakers. </p>
<p>We deliberately modelled the multi-disciplinary assessment process on a working group of the IPCC to distill the science into an easy-to-read and concise narrative for politicians and the general public alike. It provides a community assessment of levels of certainty around what we know.</p>
<p>We hope this “sea change” summary sets a new benchmark for translating marine research into policy responses. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graphic illustrating how the system-level assessment of marine ecosystems came together, showing a group of people at a table with concentric circles in the background including observations, drivers of change and ecosystem services" src="https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=749&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=749&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=749&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=942&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=942&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554169/original/file-20231017-15-6w52ns.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=942&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Our system-level assessment addressed the multiple drivers of ecosystem change in the Southern Ocean.</span>
<span class="attribution"><a class="source" href="https://zenodo.org/records/8359585">Constable, A.J. et al (2023) Marine Ecosystem Assessment for the Southern Ocean.</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>So what’s in the report?</h2>
<p>Southern Ocean habitats, from the ice at the surface to the bottom of the deep sea, are changing. The warming of the ocean, decline in sea ice, melting of glaciers, collapse of ice shelves, changes in acidity, and direct human activities such as fishing, are all impacting different parts of the ocean and their inhabitants.</p>
<p>These organisms, <a href="https://theconversation.com/an-ocean-like-no-other-the-southern-oceans-ecological-richness-and-significance-for-global-climate-151084">from microscopic plants to whales</a>, face a changing and challenging future. Important foundation species such as Antarctic krill are likely to decline with consequences for the whole ecosystem.</p>
<p>The assessment stresses climate change is the most significant driver of species and ecosystem change in the Southern Ocean and coastal Antarctica. It calls for urgent action to curb global heating and ocean acidification.</p>
<p>It reveals an urgent need for international investment in <a href="https://theconversation.com/we-landed-a-camera-on-venus-before-seeing-parts-of-our-own-oceans-its-time-to-ramp-up-observations-closer-to-home-212970">sustained, year-round and ocean-wide</a> scientific assessment and observations of the health of the ocean. </p>
<p>We also need to develop better integrated models of how individual changes in species along with human impacts will translate to system-level change in the different food webs, communities and species.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1711094111305089149"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/antarcticas-heart-of-ice-has-skipped-a-beat-time-to-take-our-medicine-202729">Antarctica's heart of ice has skipped a beat. Time to take our medicine</a>
</strong>
</em>
</p>
<hr>
<h2>What’s next?</h2>
<p>Our report will be tabled at <a href="https://meetings.ccamlr.org/en">this week’s international meeting</a> of the Commission for the Conservation of Antarctic Marine Living Resources in Hobart.</p>
<p>The commission is the international body responsible for the conservation of marine ecosystems in the Southern Ocean, with membership of 26 nations and the European Union.</p>
<p>It is but one of the bodies our new report can assist. Currently assessments of change in habitats, species and food webs in the Southern Ocean are compiled separately for at least ten different international organisations or processes.</p>
<p>The Southern Ocean is a crucial life-support system, not just for Antarctica but for the entire planet. So many other bodies will need the information we produced for decision-making in this critical decade for action on climate, including the IPCC itself.</p>
<p>Beyond the science, the assessment team has delivered important lessons about how coordinated, collaborative and consultative approaches can deliver ecosystem information into policymaking. Our first assessment has taken five years, but this is just the beginning. Now we’re up and running, we can continue to support evidence-based conservation of Southern Ocean ecosystems into the future. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/record-low-antarctic-sea-ice-is-another-alarming-sign-the-oceans-role-as-climate-regulator-is-changing-204680">Record low Antarctic sea ice is another alarming sign the ocean's role as climate regulator is changing</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/215529/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew J Constable has worked for the Australian Public Service in the Australian Antarctic Division, received funding from Pew Charitable Trusts, and, for the marine ecosystem assessment for the Southern Ocean, he received funding from environmental and fisheries non-government organisations (details are identified in the Summary for Policy Makers).</span></em></p><p class="fine-print"><em><span>Jess Melbourne-Thomas receives funding from the Climate Systems Hub of the Australian Government’s National Environmental Science Program, and the Fisheries Research and Development Corporation.</span></em></p>The first comprehensive assessment of trends in Southern Ocean ecosystems reveals an urgent need to address climate change. The summary for policymakers can guide decision-makers.Andrew J Constable, Adviser, Antarctica and Marine Systems, Science & Policy, University of TasmaniaJess Melbourne-Thomas, Transdisciplinary Researcher & Knowledge Broker, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2062852023-07-13T20:56:33Z2023-07-13T20:56:33ZReversing the decline in shark and ray populations is possible, but requires strong governance and management<figure><img src="https://images.theconversation.com/files/531993/original/file-20230614-17-l5ljpl.jpg?ixlib=rb-1.1.0&rect=190%2C539%2C1358%2C815&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sharks and rays are rapidly declining globally, and their situation is representative of many other exploited marine species that lack scientific monitoring.</span> <span class="attribution"><span class="source">(Carlos Diaz/Ocean Image Bank)</span></span></figcaption></figure><p>The oceans remain vast and inscrutable. While technology has revolutionized our capacity to track threats to biodiversity on land, our understanding of the status of marine biodiversity remains <a href="https://doi.org/10.1126/science.abj0211">fragmented and biased toward economically high-valued species</a>. </p>
<p><a href="https://doi.org/10.1111/faf.12593">Most fish species are not scientifically monitored</a>, which is done by collecting and analyzing population data. Global marine fish catches continue to be underestimated, with as much as <a href="https://doi.org/10.1038/ncomms10244">one-third missing</a>.</p>
<p>The fast decline of shark and ray species globally is representative of many other exploited marine species that lack scientific monitoring and <a href="https://doi.org/10.1016/j.ocecoaman.2019.104994">a general political will for fisheries management</a>. </p>
<p><a href="https://doi.org/10.1038/s41586-020-03173-9">Seventy-one per cent of oceanic shark and ray populations have been depleted in the last half-century</a> and <a href="https://doi.org/10.1016/j.cub.2021.08.062">one-third of all 1,199 shark and ray species are now threatened with extinction</a>, based on the International Union for Conservation of Nature (IUCN) criteria, primarily due to overfishing. These species have a key role in marine ecosystem functioning and human food security.</p>
<p>Fortunately, there are signs of hope. New scientific techniques and recent efforts of the scientific community have helped create a more comprehensive picture of the speed and scale of these changes, highlighting successful cases of protection and management efforts, including those in <a href="https://doi.org/10.1016/j.cub.2016.12.017">Australia, New Zealand, the United States, Canada and the European Union</a>.</p>
<h2>Coastal sharks and rays missing in some areas, thrive in others</h2>
<p>In 2019, our team of experts carried out IUCN Red List assessments in the Bahamas to determine the global extinction risk status of several sharks and rays.</p>
<p>We found ourselves attempting to reconcile widely divergent views of the regional status of species that were more common in the northwest Atlantic and rare or near absent in the southwest Atlantic.</p>
<p>To understand the reasons for this difference, we gathered data on population status of all 26 coastal sharks and rays — ranging from north to south — across the western Atlantic Ocean, examining the factors like fishing pressure and management effort that could influence the extinction risk status of these species.</p>
<p>We found that <a href="https://doi.org/10.1073/pnas.2216891120">populations of the same species had collapsed in the southwest Atlantic due to unrestrained fishing</a>. Across the whole region, we saw that although fishing pressure increased extinction risk, the strength of management engagement was widely overlooked, despite it reducing the extinction risk of all 26 wide-ranging sharks and rays. </p>
<p>The bonnethead shark species (<em>Sphyrna tiburo</em>) is an excellent <a href="https://www.iucnredlist.org/species/39387/205765567#population">example</a> of what is happening in the Western Atlantic region. The species is abundantly found in the northern part of its range. But further south, it hasn’t been seen in decades.</p>
<figure class="align-center ">
<img alt="A bonnethead shark swims in green waters" src="https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=365&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=365&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=365&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=459&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=459&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537189/original/file-20230713-25-7ws8w7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=459&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Abundantly found in the northern Atlantic waters, bonnethead sharks are no longer seen in the south.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>So, why is this happening?</p>
<p>In the United States, this shark species is managed by catch quota, while in Mexico there is a seasonal fishery quota. The Bahamas has been dubbed a ‘<a href="https://oceanographicmagazine.com/features/true-value-shark-sanctuaries/">shark sanctuary</a>’ because of their ban on commercial shark fishing.</p>
<p>Further south, there is no discernible management and this species is captured in unregulated targeted fisheries and as retained incidental catch. Down south, this species is likely subject to heavy unmanaged fishing pressure in most countries. It is very rarely found in Colombia and has collapsed in Brazil where there are very few recent records.</p>
<h2>A road map for shark recovery</h2>
<p>The <a href="https://www.fisheries.noaa.gov/sustainable-fisheries/atlantic-shark-fisheries-management-highlights-timeline#1993">U.S. Fishery Management Plan for Sharks of the Atlantic Ocean</a> was implemented by the National Oceanic and Atmospheric Administration in 1993.</p>
<p>This plan was developed in response to the <a href="https://www.fisheries.noaa.gov/sustainable-fisheries/atlantic-shark-fisheries-management-highlights-timeline#1976">intense expansion of commercial and recreational fisheries in the 1970s to 1980s due to the increased global demand for shark meat, fins and cartilage as well as the concerns about their effects on shark populations</a>.</p>
<p>We found that populations in the northwest Atlantic recovered shortly after the implementation of this management plan.</p>
<figure class="align-right ">
<img alt="A pile of fish." src="https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531984/original/file-20230614-15-yyoovi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Requiring sharks to be brought ashore with fins attached as per the Shark Conservation Act of 2010 vastly improved species identification and the quality of data, providing a better means for enforcing regulations.</span>
<span class="attribution"><span class="source">(NOAA Fisheries)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Thirty years after this implementation, we found the stabilization of three populations. We also documented the rebuilding population of six of the 11 coastal sharks here. </p>
<p>We believe that this success can be attributed to:</p>
<ul>
<li><p>A strong regulation system where catch is prohibited for some species (or group of species) and limited for others. A system that improves catch reporting and reduces the pressure of fishing through the reduction of the number of shark-directed fishing permits.</p></li>
<li><p>strict enforcement by the U.S. Coast Guard and law enforcement agencies for fishers in U.S. waters</p></li>
<li><p>continuous monitoring of the fishery for data collection</p></li>
</ul>
<h2>Recovering species population through collaboration</h2>
<p>Our research found that halting and reversing declines and creating sustainable fisheries is possible even for wide-ranging sharks and rays.</p>
<p>But this requires strong governance and management.</p>
<p>Concerted efforts can bridge the spots of successful management and recovery with adjacent nations where the species are still in decline, leading to success at a global scale. This approach will ensure that successful conservation in one country is not undone by less regulated fishing areas outside those borders.</p>
<p>Developed nations, that are bringing their fisheries into sustainability and importing more fish, should translate their successes into capacity-building lessons to support other nations undergoing the transition towards sustainability.</p><img src="https://counter.theconversation.com/content/206285/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was funded by the Shark Conservation Fund as part of the Global Shark Trends Project</span></em></p>Through regulation, enforcement and monitoring, fisheries management can lead to recoveries in shark and ray populations.Nathan Pacoureau, Postdoctoral Research Fellow, Global Shark Trends Project, Simon Fraser UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2039082023-04-18T20:01:01Z2023-04-18T20:01:01ZA forgotten and neglected ecosystem covers a third of Earth’s coastlines, with a collective value of $500 billion<figure><img src="https://images.theconversation.com/files/521495/original/file-20230418-20-ivxgck.jpg?ixlib=rb-1.1.0&rect=67%2C40%2C2874%2C1935&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Joe Belanger/Shutterstock</span></span></figcaption></figure><p>Underwater forests known as kelp have been sustaining people and cultures for millennia. However, most of us are only vaguely aware of the vibrant masses of seaweed hugging the ocean shores around Earth. Furthermore, we don’t realise how valuable and necessary they really are.</p>
<p>In a new study <a href="https://doi.org/10.1038/s41467-023-37385-0">published today in Nature Communications</a>, we have produced the first global estimate of the economic value of kelp forests – revealing they provide hundreds of billions of dollars in value to humans across the world.</p>
<h2>A human history of kelp</h2>
<p>Along the Pacific, kelp harvest has long played an important role in Asian societies. In Japan, seaweed was among the marine products people could use to pay taxes, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/raq.12524">according to a law code from the year 701</a>.</p>
<p>In Medieval Europe, kelp was used to fertilise soil and increase crop yields, to treat <a href="https://www.healthdirect.gov.au/goitre#:%7E:text=Goitre%20is%20an%20enlarged%20thyroid,hard%20to%20breathe%20or%20swallow.">goitre</a>, and was used to fortify building materials <a href="https://link.springer.com/chapter/10.1007/978-94-009-4057-4_24">for centuries</a>. In the 21st century kelp forests have become the <a href="https://link.springer.com/chapter/10.1007/978-981-10-6910-9_2">main source for alginate</a>, a common food and medical additive.</p>
<p>And throughout this time, kelps have supported <a href="https://www.cambridge.org/core/journals/environmental-conservation/article/kelp-forest-ecosystems-biodiversity-stability-resilience-and-future/105EB05670376912F180E116D64135D6">teeming ecosystems</a> and important <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12483">fisheries</a> of abalone, lobsters and many different types of fishes. Through their prolific productivity, kelp forests <a href="https://link.springer.com/article/10.1007/s12601-015-0001-9">draw carbon from the atmosphere</a>, exude oxygen, and help reduce <a href="https://www.int-res.com/abstracts/meps/v531/p155-166/">nutrient pollution in our oceans</a>.</p>
<p>A marine marvel, hidden kelp forests spread across <a href="https://www.researchgate.net/publication/327606143_Status_and_Trends_for_the_World%27s_Kelp_Forests">almost one third of our world’s coastlines</a> and lie within 50km of 740 million people. If you live in London, Tokyo, New York, Vancouver, Santiago, Cape Town, Los Angeles or Lisbon, you have one of these ecosystems on your doorstep.</p>
<p>Yet they tend to be forgotten or misunderstood. People often aren’t even aware of a kelp forest, and if they are, they might be most familiar with a pile of decomposing seaweed on the beach after a storm.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An underwater view of seaweed in blue water with fishes swimming through" src="https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A kelp forest is a rich habitat, a provider of oxygen and a sequester of carbon.</span>
<span class="attribution"><span class="source">Andrew b Stowe/Shutterstock</span></span>
</figcaption>
</figure>
<p>This disconnect has real-world implications. Despite sitting next to some of the biggest research centres on the planet and likely covering <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/geb.13515">more seafloor than any other biotic habitat</a>, research and conservation of kelp forests is <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jpy.13239">terribly behind</a> other ecosystems.</p>
<p>This knowledge gap impedes desperately needed action and conservation. Kelp populations in <a href="https://www.nature.com/articles/s41598-019-51114-y">northern California</a>, <a href="https://www.int-res.com/abstracts/meps/v653/p1-18/">Tasmania</a>, and the <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229703">Salish Sea</a> have all but disappeared in living memory. Elsewhere, kelp populations have been <a href="https://www.pnas.org/doi/10.1073/pnas.1606102113">continually declining</a> over the last 50 years.</p>
<p>What we value and how we value it is actually quite a complicated process. And despite the fact we make value judgements over and over each day, we have a really poor understanding of something’s value if it doesn’t have a price tag on it.</p>
<p>Our natural world is perhaps the ultimate value provider – everything we do in our societies is ultimately tied to nature, ecosystems, and a healthy planet. But because these processes and benefits happen with or without humans, they are often taken for granted.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A white sandy beach with masses of black seaweed lying in the sun" src="https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The seaweed we step over on our beaches is just a small fraction of the vibrant kelp ecosystems beneath the waves.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/1Y-x8lPnqDU">Andrew Dawes/Unsplash</a></span>
</figcaption>
</figure>
<h2>So, what is the ‘value’ of a kelp forest?</h2>
<p>Our research has brought together data from all across our oceans to produce a global estimate of the economic value of kelp forest ecosystems. Looking at six key genera of kelp – <em>Macrocystis</em>, <em>Nereocystis</em>, <em>Laminaria</em>, <em>Saccharina</em>, <em>Ecklonia</em>, and <em>Lessonia</em> – and the potential economic value of the fisheries they support, the carbon they pull from the atmosphere, and the nutrient pollution they remove from the water, we found that kelp forests are valued at US$500 billion per year.</p>
<p>The highest of these values was the removal of excess nitrogen from the water, which can trigger blooms of algae, reduced water quality, and <a href="https://www.usgs.gov/mission-areas/water-resources/science/nutrients-and-eutrophication">ultimately oxygen-depleted dead zones</a>.</p>
<p>A close second was the fisheries values – kelp forests support some of our most iconic fisheries, including lobster and abalone.</p>
<p>Lastly, despite finding the carbon sequestration of kelp forests was comparable to other terrestrial and marine ecosystems, the economic value was much lower, as society has yet to place a high price on carbon. This finding suggests that carbon credits may not be an economic driver of kelp conservation, but kelp forests still play an important role in the blue carbon cycle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An orange fish with a long snout and limbs swimming among kelp" src="https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Weedy seadragons are just one of many fishes living in kelp forests.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/johnwturnbull/41749070410/in/album-72157703596928075/">John Turnbull/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>The future of kelp</h2>
<p>When nature is treated as a freebie, where we can take what we want and not pay for the damages, this attitude has direct consequences; people and the environment suffer.</p>
<p>First, it can mean that people and government don’t see the value in protecting and restoring ecosystems. Second, development projects are <a href="https://theconversation.com/environment-laws-have-failed-to-tackle-the-extinction-emergency-heres-the-proof-122936">able to destroy nature</a> without compensating for those damages.</p>
<p>Lastly, it leads to poor management. How can we manage something if we cannot quantify it? Imagine if you didn’t know where your bank account was, or how much money was in it.</p>
<p>The battle to save our kelp forests is just getting started, and we need greater action to protect these intrinsically and economically valuable marine ecosystems.</p>
<p>That is why researchers like me have started the not-for-profit <a href="https://kelpforestalliance.com/who-we-are">Kelp Forest Alliance</a>, and have now launched the <a href="https://kelpforestalliance.com/kelp-forest-challenge">Kelp Forest Challenge</a>, a global call to protect and restore 4 million hectares of kelp forest by 2040. This is a call for governments to meet their commitments to the <a href="https://www.unep.org/resources/kunming-montreal-global-biodiversity-framework">Kunming-Montreal Global Biodiversity Framework</a> and act now to save these ecosystems and #HelpTheKelp.</p>
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Read more:
<a href="https://theconversation.com/whether-youre-a-snorkeller-or-ceo-you-can-help-save-our-vital-kelp-forests-202620">Whether you're a snorkeller or CEO, you can help save our vital kelp forests</a>
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<img src="https://counter.theconversation.com/content/203908/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aaron Eger is the Founder and Program Director of the Kelp Forest Alliance, a research driven not-for-profit organization. He is also a Postdoctoral Research Fellow at the University of New South Wales Sydney. The Kelp Forest Alliance is supported by the Nature Conservancy, The Banner Foundation, the Van Dyson Foundation, and UNSW Sydney.</span></em></p>We cannot afford to ignore kelp – these vibrant underwater forests have sustained people and ecosystems for centuries, and continue to do so today.Aaron Eger, Postdoctoral research fellow, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2025702023-04-07T12:20:19Z2023-04-07T12:20:19ZThe Great Atlantic Sargassum Belt is carrying a massive bloom of brown seaweed toward Florida and the Caribbean<figure><img src="https://images.theconversation.com/files/519655/original/file-20230405-18-1qef2c.jpg?ixlib=rb-1.1.0&rect=8%2C4%2C2986%2C1989&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sargassum seaweed started washing up in Fort Lauderdale, Florida, in mid-March 2023.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/beachgoers-walk-past-seaweed-that-washed-ashore-on-march-16-news-photo/1473976187">Joe Raedle/Getty Images</a></span></figcaption></figure><p>An unwelcome visitor is headed for Florida and the Caribbean: huge floating mats of <a href="https://oceanexplorer.noaa.gov/facts/sargassum.html">sargassum</a>, or free-floating brown seaweed. Nearly every year since 2011, sargassum has inundated <a href="https://www.nola.com/news/environment/article_d23f12b6-8f21-11eb-9a26-d7b9068fcc1b.html">Caribbean</a>, <a href="https://www.theguardian.com/environment/2020/jun/30/how-do-you-deal-with-9m-tonnes-of-suffocating-seaweed-aoe">Gulf of Mexico</a> and <a href="https://www.tcpalm.com/story/news/local/indian-river-lagoon/2021/05/28/sargassum-seaweed-florida-beaches-10-things-know-algae-sargasso-sea-gulfweed-sea-holly/7428135002/">Florida</a> coastlines in warm months, peaking in June and July. This brown tide rots on the beach, <a href="https://www.costar.com/article/1897972322">driving away tourists</a>, harming local fishing industries and requiring costly cleanups. </p>
<p>According to scientists who monitor the formation of sargassum in the Atlantic Ocean, 2023 could produce the <a href="https://optics.marine.usf.edu/projects/SaWS/pdf/Sargassum_outlook_2023_bulletin3_USF.pdf?ftag=YHF4eb9d17">largest bloom ever recorded</a>. That’s bad news for destinations like Miami and Fort Lauderdale that will struggle to clean their shorelines. In 2022, Miami-Dade County spent US$6 million to clear sargassum from just <a href="https://www.union-bulletin.com/news/national/seaweed-mass-expands-reaches-record-tonnage-in-florida/article_172d44e9-44ea-58d9-bca9-f8087d92b3a2.html">four popular beaches</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of the central Atlantic with colored pixels showing concentrations of sargassum." src="https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=194&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=194&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=194&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=244&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=244&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519870/original/file-20230406-26-9shjs0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=244&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">Satellite image of sargassum concentrations in the Atlantic during the month of March.</span>
<span class="attribution"><span class="source">USF/NOAA</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Sargassum isn’t new on South Florida beaches, but its rapid increase over the past decade indicates that some new factor – likely related to human actions – is affecting when and how it forms. </p>
<p>In my work as a <a href="https://scholar.google.com/citations?user=0QZKY20AAAAJ&hl=en">coastal scientist</a>, I’ve watched these invasions become the new normal, choking beaches and turning clear blue waters golden brown. Along with other researchers, I’m trying to understand why sargassum has proliferated into this new sprawling bloom, how to deal with such massive amounts of it, and how affected countries can predict the severity of the next influx. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/IrSL4t7uwyI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Sargassum has a valuable ecological role at sea, but on beaches it’s an expensive nuisance that threatens tourism.</span></figcaption>
</figure>
<h2>A biological hot spot at sea</h2>
<p>Sargassum grows in the calm, clear waters of the <a href="https://oceanservice.noaa.gov/facts/sargassosea.html">Sargasso Sea</a> – a 2 million-square-nautical-mile (5.2 million-square-kilometer) haven of biodiversity that lies east of Bermuda in the Atlantic Ocean. Rather than beaches, it’s bounded by <a href="https://oceanservice.noaa.gov/facts/gyre.html">rotating ocean currents</a> that form the North Atlantic Subtropical Gyre.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of Atlantic Ocean currents forming a large gyre." src="https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519656/original/file-20230405-14-auosqo.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&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 Sargasso Sea in the North Atlantic is bounded by the Gulf Stream to the west, the North Atlantic Current to the north, the Canary Current to the east, and the North Equatorial Current to the south.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Sargasso_Sea#/media/File:North_Atlantic_Gyre.png">Jack/Wikipedia</a></span>
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<p>In the open ocean, islands of sargassum create a <a href="http://www.sargassoseacommission.org/sargasso-sea/about-the-sargasso-sea">rich ecosystem</a> that ocean explorer Sylvia Earle calls “<a href="https://www.bushcenter.org/catalyst/environment/bridgeland-earle-oceans.html">a golden floating rainforest</a>.” Suspended by round “berries” filled with gas, the seaweed offers food, sanctuary and breeding grounds for crabs, shrimp, whales, migratory birds and some 120 species of fish. Mats of it form the sole spawning grounds for European and American eels and habitat for some <a href="http://www.sargassoseacommission.org/storage/documents/Sargasso.Report.9.12.pdf">43 other threatened or endangered species</a>. </p>
<p>Sargassum also shelters sea turtle hatchlings and juvenile fish during their early life in the open ocean. <a href="http://www.sargassoseacommission.org/index.php?option=com_content&view=article&id=106">Ten endemic species</a> live nowhere else on Earth. The Sargasso is a valuable commercial fishery worth about <a href="https://www.sargassoseacommission.org/about-the-sargasso-sea">$100 million per year</a>.</p>
<p>But in recent years, large quantities of sargassum have drifted west, forming what researchers call the Great Atlantic Sargassum Belt. As of late March 2023, the sargassum belt was about <a href="https://optics.marine.usf.edu/projects/SaWS.html">5,000 miles (8,000 kilometers) long and 300 miles (500 miles) wide</a> </p>
<p>The belt is actually a collection of island-like masses that can stretch for miles. It doesn’t uniformly cover beaches when it washes up: Some areas can be relatively clear or only mildly affected. But the overall mass this year is overwhelming. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1643418018251145216"}"></div></p>
<h2>What’s fertilizing huge blooms?</h2>
<p>What can plausibly explain the sudden increase in this floating seaweed since 2011 – the first time that large aggregations of sargassum were detected from space? While climate change is warming ocean waters, and sargassum grows faster in warmer water, I believe it’s more plausible that the cause is a <a href="https://theconversation.com/the-great-amazon-land-grab-how-brazils-government-is-clearing-the-way-for-deforestation-173416">drastic increase in agricultural activity</a> in the Brazilian Amazon. </p>
<p>Scientists have shown that huge brown tides that were observed in the Gulf of Mexico in 2005 and 2011 were linked to <a href="https://doi.org/10.1038/nature12860">nutrients carried down the Mississippi River</a>. Now, intensive cattle ranching and soybean farming in the Amazon basin are sending <a href="https://www.nola.com/news/environment/amazon-destruction-linked-to-the-largest-belt-of-algae-on-the-planet/article_8f73ac64-8916-11eb-8ca1-2b9612ea17ff.html">rising levels of nitrogen and phosphorus</a> into the Atlantic Ocean via the Amazon and Orinoco rivers. These nutrients are key ingredients in fertilizer, and also are present in animal manure.</p>
<p>Another major source of nutrients is dust clouds from the Sahara, which can stretch for thousands of miles across the Atlantic Ocean, carried by trade winds. These clouds contain iron, nitrogen and phosphorus from dust storms in Saharan Africa and <a href="https://doi.org/10.1038/s41467-021-23135-7">biomass burning in central and southern Africa</a>. As they blow across the Atlantic, they help fertilize seaweed. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of the globe with brown plumes blowing west from northern Africa." src="https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=601&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=601&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=601&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=755&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=755&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519658/original/file-20230405-22-vmxxs0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=755&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map shows dust from a series of Saharan storms crossing the Atlantic on June 28, 2018.</span>
<span class="attribution"><a class="source" href="https://eoimages.gsfc.nasa.gov/images/imagerecords/92000/92358/dust_geo_2018179_lrg.png">NASA Earth Observatory</a></span>
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<h2>A threat to sea life</h2>
<p>Along with its devastating effects on recreational beaches in the Caribbean and South Florida, sargassum has important but less visible ecological impacts near the coast. Large floating mats of sargassum block sunlight, which is essential for the survival of underwater grasses. These grasses stabilize the seafloor and provide food and shelter for many species of fish and invertebrates and for Florida’s endangered manatees.</p>
<p>Coral reefs also require sunlight and clean water to survive. Reefs in Florida and the Caribbean are under <a href="https://www.epa.gov/coral-reefs/americas-coral-reefs">many other stresses</a>, including ocean warming and coral bleaching, so they are already highly vulnerable.</p>
<p>Thick masses of sargassum on beaches can make it difficult or impossible for <a href="https://www.fisheries.noaa.gov/sea-turtles">endangered sea turtles</a> to dig nests and lay eggs on beaches. Spring and summer, when sargassum accumulates, are prime sea turtle nesting seasons. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A manatee grazes on underwater grasses." src="https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519661/original/file-20230405-24-ch63cz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A manatee feeding on seagrass in Homosassa, Fla. Starvation due to loss of seagrass beds has been a primary cause of manatee deaths in Florida in recent years.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/manatee-swims-in-the-homosassa-river-on-october-05-2021-in-news-photo/1345029768">Joe Raedle/Getty Images</a></span>
</figcaption>
</figure>
<h2>Taming the sargassum monster</h2>
<p>Researchers across the Caribbean are working to find productive uses for these enormous quantities of organic material that float ashore. In South Florida, communities mainly use the seaweed as mulch, but this requires thoroughly washing it to remove the salt, either naturally via rainfall or by spraying it with fresh water. Recycling sargassum into fertilizer for use on crops is problematic because it often contains toxic heavy metals such as arsenic and cadmium.</p>
<p>Sargassum has become a recurring seaweed monster, but humanity is the real villain. Until nations find ways to reduce large-scale nutrient pollution, I expect that huge sargassum blooms will be a recurring presence in Florida and the Caribbean. </p>
<p><em>This is an update of an <a href="https://theconversation.com/whats-driving-the-huge-blooms-of-brown-seaweed-piling-up-on-florida-and-caribbean-beaches-163058">article</a> published Aug. 2, 2021.</em></p><img src="https://counter.theconversation.com/content/202570/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen P. Leatherman 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>Scientists are predicting a record sargassum bloom in 2023. It’s already starting to wash up on beaches in Florida and the Caribbean and cause a stink.Stephen P. Leatherman, Professor of Coastal Science, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1954582023-01-10T13:17:12Z2023-01-10T13:17:12ZFirst study to estimate ‘blue carbon’ storage in South Africa is useful for climate strategy<figure><img src="https://images.theconversation.com/files/503772/original/file-20230110-25-o03m5z.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C5145%2C2987&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Flamingos feeding in salt marsh on an estuary in South Africa's Western Cape province. </span> <span class="attribution"><span class="source">Geoff Sperring/Shutterstock</span></span></figcaption></figure><p>Marine ecosystems have a valuable role to play in mitigating the effects of climate change. That’s because such ecosystems – and, particularly, vegetated tidal ecosystems like mangroves and salt marshes – capture and store a <a href="https://www.grida.no/publications/145">significant amount of atmospheric carbon dioxide (CO₂)</a>. CO₂ has accumulated in Earth’s atmosphere at unprecedented levels <a href="https://www.noaa.gov/news-release/carbon-dioxide-now-more-than-50-higher-than-pre-industrial-levels">since the industrial revolution</a>. Scientific evidence shows this is the <a href="https://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/">primary driver of climate change</a>.</p>
<p>“<a href="https://climatechampions.unfccc.int/what-is-blue-carbon/">Blue carbon</a>”, the term used to describe CO₂ absorbed by marine ecosystems, was an <a href="https://www.iaea.org/newscenter/news/iaea-cop27-event-focuses-on-blue-carbon-as-a-nature-based-climate-solution">important topic of discussion</a> at last year’s COP27 talks in Egypt. </p>
<p>More countries are bringing blue carbon into their climate change plans and policies. Indonesia, for example, has made <a href="https://www.afd.fr/en/actualites/fifth-worlds-mangroves-indonesia-boosting-its-blue-carbon-strategy">climate adaptation and mitigation efforts that focus on blue carbon</a> a key component for achieving its <a href="https://www.un.org/en/climatechange/all-about-ndcs">Nationally Determined Contributions</a> target by 2030.</p>
<p>But, partly because of gaps in scientific knowledge, countries may not know how much potential blue carbon they have or where it is located. There are also ecological, social and economic aspects to consider. These differ from place to place, so (although <a href="https://www.thebluecarboninitiative.org/policy-guidance">guidelines exist</a> and countries can learn from each other) a “one size fits all” approach isn’t useful.</p>
<p>South Africa is globally recognised for its <a href="http://www.enviropaedia.com/topic/default.php?topic_id=156">marine heritage</a>. Its marine ecosystems are not only beautiful and diverse: they also bring economic and social benefits through job creation and contributing to food security. This makes it an imperative to implement targeted climate change policies for marine and coastal ecosystems – and to centre blue carbon in these plans.</p>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0048969722072424?dgcid=author">recent study</a> was the first national blue carbon sink assessment for South Africa. It offers a comprehensive estimate of blue carbon storage across the country. That’s an important element in supporting the development of evidence-based blue carbon strategies. </p>
<p>While national blue carbon stocks are naturally limited by the distribution of mangroves, salt marshes and seagrasses; South Africa does have existing policies that can be used to protect and restore these ecosystems. </p>
<h2>Creating a database</h2>
<p>Mangroves, salt marshes and seagrasses are the definitive blue carbon ecosystems. Unlike forests, or other terrestrial ecosystems, more than 90% of the carbon is locked into the soil rather than in the plants themselves. The soils of blue carbon ecosystems are waterlogged with salty seawater. This prevents the stored organic carbon from being converted back to CO₂ through remineralisation. If left undisturbed and subject to certain conditions, these carbon stocks can build up over <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/110004">centuries</a>.</p>
<p>In total, we found that blue carbon ecosystems in South Africa cover a relatively small area of around 18,500 hectares. That represents only 0.015% of the total land area. This is because mangroves, salt marshes and seagrasses can only occur in estuaries with certain environmental conditions, making their distribution <a href="https://theconversation.com/mangrove-forests-wont-be-able-to-spread-further-in-south-africa-so-protecting-them-is-crucial-193547">quite limited</a>. </p>
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Read more:
<a href="https://theconversation.com/mangrove-forests-wont-be-able-to-spread-further-in-south-africa-so-protecting-them-is-crucial-193547">Mangrove forests won't be able to spread further in South Africa, so protecting them is crucial</a>
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<p>Next, we needed to calculate how much CO₂ these blue carbon ecosystems hold. To do so, we collated the information about where mangroves, salt marshes and seagrasses occur with the available data from studies that have measured carbon stocks.</p>
<p>Using <a href="https://www.ipcc.ch/2019/05/13/ipcc-2019-refinement/">guidelines</a> developed by the UN’s Intergovernmental Panel on Climate Change, we also estimated CO₂ emissions from blue carbon ecosystems for the period from 1930 to 2020. These emissions are linked to certain human activities. For example, if a salt marsh is completely removed and replaced with hard infrastructure, it is assumed that all the carbon it stored has been lost and converted back into CO₂. </p>
<p>However, if some of the natural area remains, then only a portion of the carbon stock has been lost, particularly if the soil is still intact, as this is where most of the carbon is stored. </p>
<p>We estimated that total ecosystem carbon stocks per unit area (in megagrams of carbon per hectare) range from 253-534 Mg C ha⁻¹ for mangroves to 100-199 Mg C ha⁻¹ for salt marshes and 45-144 Mg C ha⁻¹ for seagrasses. This is more than the top three vegetated natural terrestrial ecosystems in South Africa: indigenous forest, grasslands and thicket.</p>
<p>We also found that 26%, or about 6,500 hectares, of the historical extent of blue carbon ecosystems has been lost through human activities. This has led to historical emissions on average of 30,266 tonnes of CO₂ per year. For comparison, the <a href="https://www.icao.int/environmental-protection/Carbonoffset/Pages/default.aspx">CO₂ emissions per passenger</a> on a flight from Johannesburg to Durban is estimated at 0.0736 tonnes of CO₂ per year: one person would need to make the trip about 400,000 times in a year to equal the emissions lost from blue carbon ecosystems. </p>
<p>Some of the degraded blue carbon ecosystems could be restored. Done successfully, this could increase the total annual carbon sequestration of blue carbon ecosystems by 18%.</p>
<h2>Blue carbon future</h2>
<p>Our findings offer important information about South Africa’s blue carbon ecosystems. Protecting and managing these ecosystems, we argue, needs to be integrated into coastal management practices, biodiversity conservation, national and provincial climate adaptation strategies, and blue economy planning. </p>
<p>This won’t require new laws. South Africa has a number of existing policies and measures that can be used to reach these goals. But it will require a concerted effort across all spheres of government (local, provincial, and national) to prioritise and mainstream blue carbon ecosystem protection and sustainable use. </p>
<p>Our study identified principal climate change mitigation opportunities with co - benefits for adaptation and biodiversity conservation. These include conservation and rehabilitation activities that can be used under <a href="https://unfccc.int/process-and-meetings/the-paris-agreement/the-glasgow-climate-pact/cop26-outcomes-market-mechanisms-and-non-market-approaches-article-6#COP26:-what-did-countries-agree-with-regard-to-mar">article 6 of the Paris Agreement</a> under marked based approaches to service Agriculture, Forestry and Other Land Use sectoral targets of the climate change mitigation system for South Africa.</p><img src="https://counter.theconversation.com/content/195458/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacqueline L Raw contributed this article following work performed for Nelson Mandela University. She received funding from the National Research Foundation (NRF) and this research was funded by the GIZ (Deutsche Gesellschaft für Internationale Zusammenarbeit). </span></em></p><p class="fine-print"><em><span>Hlengiwe Mbatha is affiliated with the Department of Forestry, Fisheries and Environment. Although the independent research and findings contained in this report do not necessarily represent the views, opinions and/or position of government, the department believes that this research is critical to enhance our understanding of the role of Blue Carbon Ecosystems in supporting climate change strategies.
</span></em></p>By adapting and applying existing policies, South Africa can protect and restore its critical ‘blue carbon’ sinks.Jacqueline L Raw, Postdoctoral Researcher (DST-NRF Innovation Fellow) DST-NRF Research Chair in Shallow Water Ecosystems Ocean Sciences Campus, Nelson Mandela UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1965252023-01-05T11:54:10Z2023-01-05T11:54:10ZUrban light pollution is a danger for marine ecosystems – new research<figure><img src="https://images.theconversation.com/files/501350/original/file-20221215-15-2eals8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5982%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artificial light is an emerging threat for marine ecosystems in coastal waters (Kochi, India).</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/marine-drive-kochi-kerala-india-784637686">Vinu Sebastian/Shutterstock</a></span></figcaption></figure><p>Cities are artificially lit to allow humans to make use of the night. This light pollution means that stars are often barely visible in urban skies. But reduced stargazing is not the only <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13927">impact of artificial light at night</a>. </p>
<p>Urban development in coastal areas is increasingly exposing marine ecosystems to artificial light. This exposure is particularly acute in and near some of the world’s largest coastal cities and may carry physiological and behavioural consequences for the organisms that inhabit their coastal waters. </p>
<p>The <a href="https://pml.ac.uk/">Plymouth Marine Laboratory</a>, where I lead the Marine Biogeochemistry team, last year published an atlas of <a href="https://online.ucpress.edu/elementa/article/9/1/00049/119144/A-global-atlas-of-artificial-light-at-night-under">artificial light at night under the sea</a>. The atlas reveals that at a depth of 1 metre, light pollution affects 1.9 million sq km of the world’s coastal seas. This is equivalent to 3.1% of global <a href="https://emodnet.ec.europa.eu/en/map-week-%E2%80%93-exclusive-economic-zones#:%7E:text=This%20is%20called%20a%20country's,lies%20its%20Exclusive%20Economic%20Zone.">exclusive economic zones</a> (the areas of the ocean owned by coastal nations). </p>
<p>Such research has confirmed that light pollution is widespread and expanding. But the difference between the intensity and cycles of natural and unnatural light has to this point been understudied. Quantifying this would allow a better understanding of the impact of expansive urbanised coastlines on the ecology of marine ecosystems. </p>
<p>Together with colleagues from the Universities of Plymouth and Strathclyde, <a href="https://online.ucpress.edu/elementa/article/10/1/00042/194863/Disruption-of-marine-habitats-by-artificial-light">we quantified</a> the magnitude of the natural and unnatural light reaching the marine ecosystems of a group of seven coastal cities with more than 10 million inhabitants: Tokyo, Shanghai, Mumbai, New York, Buenos Aires, Lagos and Los Angeles. </p>
<p>Our research showed that for these cities, dosages of artificial light at night on the surface of the sea are up to six times greater than moonlight. Moonlight intensity only exceeded artificial lighting within a period of three days from the brightest full moons.</p>
<figure class="align-center ">
<img alt="Shanghai skyline at night from the sea." src="https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.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">Shanghai’s skyline illuminated at night.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shanghai-bund-garden-bridge-lujiazui-skyline-190208075">ArtisticPhoto/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Illuminating coastal waters</h2>
<p>Our model, which included inputs for lunar, artificial light and both daylight and twilight solar sources alongside seasonal and tidal changes in the distribution of light, was applied to each city over the course of 2020. In 15-minute time intervals we then determined the intensity of these light sources both above the sea’s surface and in the intertidal zone. This refers to the points on the shore which are covered, generally twice a day, by the tide. </p>
<p>We also applied the model to Plymouth, a coastal city in the west of England with a population of 230,000. Natural and artificial light sources have been studied here from 2001 to 2020 in order to capture the variability in tidal and lunar cycles. This fieldwork allowed us to ensure that our model provided accurate predictions.</p>
<p>In Plymouth, artificial light at night dosages generally ranked sixth across all of the cities studied. The city has a relatively northerly latitude, meaning it has long nights during the autumn and winter months. Yet summertime full moons in Plymouth shine with an intensity close to that of artificial light because the moon is close to the horizon all night with a longer atmospheric path length.</p>
<p>But the marine ecosystems likely to be most affected by light pollution are those in the coastal waters of Los Angeles, New York, Buenos Aires, Shanghai and Mumbai. Factors including tidal range and water clarity interact with the high intensity brightness of artificial urban lighting to impact marine ecosystems in these locations.</p>
<h2>Impact on marine ecosystems</h2>
<p>Natural sources of light at night have seasonal cycles. Nighttime light exposure has therefore historically been dependent on the moon and its cycle of waxing, waning and elevation in the sky. Artificial light sources, in contrast, have a fixed position irrespective of the season and shine with the same intensity throughout the night and all year round. </p>
<p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16264">Scientific research</a> has shown that light pollution can mask the natural cycle of the moon and can affect coastal organisms. This occurs at a variety of scales, from a hyperlocal (underneath street lights) to a regional and even global scale.</p>
<p>Marine organisms, including coral reefs, rely on natural light cycles to regulate their physiological and biological processes. Several coral species simultaneously <a href="https://www.sciencedirect.com/science/article/pii/S0960982220315827">release their reproductive cells</a> – called gametes – on cues from the lunar cycle.</p>
<p>Key maintenance processes in coral, such as <a href="https://www.frontiersin.org/articles/10.3389/fphys.2021.695083/full">symbiosis</a>, can also be sensitive to artificial lighting. Symbiosis describes the close relationship between the two organisms that make up coral. </p>
<p>The spectral composition of artificial light at night (its red, green and blue light components) illuminating seafloor habitats may also disrupt <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.14146">visually guided ecological processes</a>. Predators that usually feed in the day such as the herring gull may be able to see prey that would ordinarily be camouflaged at night, such as marine snails. </p>
<figure class="align-center ">
<img alt="A yellow and black street sign warning people that turtles are nesting on the beach and that street lights will be turned off." src="https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.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">Artificial light can disorientate turtle hatchlings.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fort-lauderdale-florida-january-23-2014-175410500">Serenethos/Shutterstock</a></span>
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</figure>
<p>Illuminating coastal environments can also alter the bodily functions of many marine animals. Exposure to artificial light can reduce the <a href="http://dx.doi.org/10.1098/rsbl.2019.0272">reproductive success of fish</a>. And research has also found that it can <a href="http://dx.doi.org/10.1016/0006-3207(91)90053-C">disorientate turtle hatchlings</a> and affect their ability to reach the safety of the ocean.</p>
<p>Some species are highly sensitive to even low levels of light. The daily migration of zooplankton, which are a key part of the marine food chain, can be disrupted by artificial light. <a href="https://www.nature.com/articles/s42003-020-0807-6">Research in the Arctic</a> has observed that zooplankton move away from the working light of a ship at depths of at least 200 metres.</p>
<p>Measuring light pollution in nature is a challenge because of the low intensities of light encountered. This is particularly true at greater depths. </p>
<p>But overcoming these challenges is essential to facilitate a better understanding of the ecological impact of light pollution. Research such as ours will guide biologists on future research into the impact of light pollution on marine ecosystems. It will also provide urban planners with the information necessary to balance coastal urban development with the protection of marine ecosystems.</p><img src="https://counter.theconversation.com/content/196525/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Smyth receives funding from the UK Natural Environment Research Council (grants NE/S003568/1 and NE/X006271/1).</span></em></p>Artificial lighting from cities illuminates coastal waters and can change the physiology and behaviour of marine organisms.Tim Smyth, Head of Science: Marine Biogeochemistry and Observations, Plymouth Marine LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1941462022-12-04T22:36:59Z2022-12-04T22:36:59ZLoss, decay and bleaching: why sponges may be the ‘canary in the coal mine’ for impacts of marine heatwaves<figure><img src="https://images.theconversation.com/files/498818/original/file-20221204-20-4m28m7.jpg?ixlib=rb-1.1.0&rect=38%2C333%2C5145%2C2623&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Marine sponges were thought to be more resilient to ocean warming than <a href="https://theconversation.com/the-rise-of-sponges-in-anthropocene-reef-ecosystems-105493">other organisms</a>. But earlier this year, New Zealand recorded the largest-ever <a href="https://www.theguardian.com/world/2022/jun/23/new-zealand-records-largest-ever-bleaching-of-sea-sponges">sponge bleaching event</a> off its southern coastline. </p>
<p>While only one species, the cup sponge <em>Cymbastella lamellata</em>, was affected, a prolonged marine heatwave turned millions of the normally dark brown sponges bright white.</p>
<figure class="align-center ">
<img alt="A bleached, bone white (left) and unbleached, brown (right) cup sponge Cymbastella lamellata." src="https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=232&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=232&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=232&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=291&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=291&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497275/original/file-20221124-7159-lsh2ic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=291&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A bleached (left) and healthy (right) cup sponge Cymbastella lamellata.</span>
<span class="attribution"><span class="source">Valerio Micaroni and Francesca Strano</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Subsequently, we reported tissue loss, decay and death of other sponge species across the northern coastline of New Zealand, with an estimated impact on hundreds of thousands of specimens. In contrast, we didn’t observe any bleaching or tissue loss in central areas of New Zealand’s coastline, despite extensive surveys. </p>
<p>Our <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(22)01769-9">latest research</a> shows the most severe impacts on sponges occurred in areas where the marine heatwave was most intense. The loss of sponges may have major repercussions for the whole ecosystem.</p>
<h2>Why should we care about sponges?</h2>
<p>Sponges are among the most ancient and abundant animals on rocky reefs across the world. In New Zealand, they occupy up to <a href="https://www.int-res.com/abstracts/meps/v671/p21-43/">70% of the available seafloor</a>, particularly in so-called <a href="https://theconversation.com/into-the-ocean-twilight-zone-how-new-technology-is-revealing-the-secrets-of-an-under-researched-undersea-world-182280">mesophotic ecosystems</a> at depths of 30-150m. </p>
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<p>
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Read more:
<a href="https://theconversation.com/into-the-ocean-twilight-zone-how-new-technology-is-revealing-the-secrets-of-an-under-researched-undersea-world-182280">Into the ocean twilight zone: how new technology is revealing the secrets of an under-researched undersea world</a>
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<p>They serve a number of important ecological functions. They filter large quantities of water, capturing small food particles and moving carbon from the water column to the seafloor where it can be eaten by bottom-dwelling invertebrates. These invertebrates in turn are consumed by organisms further up the food chain, including commercially and culturally important fish species. </p>
<p>Sponges also add three-dimensional complexity to the sea floor, which provides habitat for a range of other species such as crabs, shrimps and starfish.</p>
<figure class="align-center ">
<img alt="Sponge reefs, showing different types of sponges." src="https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=169&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=169&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=169&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=212&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=212&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497276/original/file-20221124-16-cnb0xd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=212&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Typical sponge reefs from Northland, New Zealand.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Sponge bleaching, tissue loss and decay</h2>
<p>Like corals, sponges contain symbiotic organisms thought to be critical to their survival. <em>Cymbastella lamellata</em> is unusual in that it hosts dense populations of diatoms, small single-celled photosynthetic plants that give the sponge its brown colour. </p>
<p>These diatoms live within the sponge tissue, exchanging food for protection. When the sponge bleaches, it expels the diatoms, leaving the sponge skeleton exposed. </p>
<p>Tissue loss occurs when sponges are stressed and either have to invest more energy into cell repair or when their food source is depleted and they reabsorb their own tissue to reduce body volume and reallocate resources. </p>
<p>Tissue decay or necrosis on the other hand is generally associated with changes in the microbial communities living within sponges and growth of pathogenic bacteria. </p>
<p>Bleaching, tissue loss and decay in sponges have all previously been associated with heat stress, but didn’t necessarily result in sponge death. In other places where such impacts have been observed, they were much more localised, compared to what we saw in New Zealand. </p>
<h2>The impact of marine heat waves</h2>
<p><a href="http://www.marineheatwaves.org">Marine heatwaves</a> are defined as unusual periods of warming that last for five consecutive days or longer. Some can last from weeks to several months and extend over hundreds or thousands of kilometres of coastline. </p>
<p>The sponge bleaching and tissue loss or decay in New Zealand matched the duration and intensity of marine heatwaves to the north and south of New Zealand during the summer of 2021/2022. The Hauraki Gulf, where sponge necrosis and decay was reported, was in a continuous marine heatwave for 29 weeks from November 2021 to the end of May 2022, with a maximum intensity of 3.77°C above normal. </p>
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<img alt="A graph showing the 2021/22 heatwave in the Hauraki Gulf." src="https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=511&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=511&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=511&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=642&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=642&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497278/original/file-20221124-24-7r3k7l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=642&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sea surface temperature in the Hauraki Gulf over the past 12 months (thin line). Red shading appears when temperatures are above the marine heatwave threshold.</span>
<span class="attribution"><a class="source" href="https://www.moanaproject.org/recent-marine-heatwaves">Moana Project</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In Fiordland, a prolonged marine heatwave developed in early February 2022 and persisted for more than 16 weeks into May, with a maximum intensity of 4.85°C above normal temperatures. In contrast, the Wellington and Marlborough Sounds regions experienced only short (weeks) marine heatwaves with a lower intensity and we did not observe any impacts on sponges. </p>
<p>These extreme heat events can result from a combination of changes in the heat exchange between the air and the sea, wind patterns and ocean currents. Their likelihood is also influenced by large-scale climate patterns such as the El Niño Southern Oscillation (<a href="https://www.climate.gov/enso">ENSO</a>). </p>
<h2>What the future may hold</h2>
<p>Most global research on climate change impacts has focused on experimental studies exposing organism to temperatures predicted for 2100, often 2-4°C higher than current temperatures. But the occurrence of marine heatwaves means organisms are already experiencing these temperatures, sometimes for several weeks or months. By 2100, marine heatwaves will become even more extreme.</p>
<p>For bleached <em>Cymbastella</em>, recent anecdotal reports suggest many sponges have recovered their colour, which is good news. However, observations immediately after the bleaching indicate many sponges were being eaten by fish, possibly because their symbionts may provide chemical defences against predation. </p>
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Read more:
<a href="https://theconversation.com/sponges-can-survive-low-oxygen-and-warming-waters-they-could-be-the-main-reef-organisms-in-the-future-173912">Sponges can survive low oxygen and warming waters. They could be the main reef organisms in the future</a>
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<p>For bleached corals, <a href="https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.13653">studies</a> have shown impacts on spawning success for many years after the event, likely because their energy reserves have been depleted. </p>
<p>We don’t yet know if this is the case for sponges. For sponges with decayed tissue the outlook is even less clear, as many probably died.</p>
<figure class="align-center ">
<img alt="A brown sponge with holes showing wheer it's being eaten." src="https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497284/original/file-20221124-14071-5lqvmw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This sponge (<em>Cymbastella lamellata</em>) has been partially eaten.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Sponges are not the only species to be affected by marine heatwaves New Zealand experienced in 2021/2022. There were reports of <a href="https://www.stuff.co.nz/environment/climate-news/130216288/marine-heatwaves-likely-cause-of-kelp-die-off-in-popular-reserve">seaweed die-offs</a> and changes to normal distribution patterns of tuna and other ecologically and <a href="https://www.stuff.co.nz/national/128524005/climate-change-could-spell-disaster-for-atrisk-marine-populations">commercially important fish species</a>. </p>
<p>Marine heatwaves should be front of mind when thinking about climate impacts. They are happening now, not in 50 years, and we don’t know enough yet to determine if sponges may be the canary in the coal mine. </p>
<p>This is especially important because New Zealand’s northern coastlines are already experiencing almost <a href="https://www.nzherald.co.nz/nz/nzs-long-lasting-marine-heatwave-breaking-records/I7NELWVNTR5P2GS36UAS4K33BA/">continuous marine heatwave conditions</a>, with the ongoing event forecast to extend into the coming summer.</p><img src="https://counter.theconversation.com/content/194146/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Bell receives funding from the George Mason Trust, Victoria University of Wellington, The Fiordland Lobster company and The Leslie Hutchins Foundation</span></em></p><p class="fine-print"><em><span>Nick Shears receives funding from Ministry of Business, Innovation and Employment - Sustainable Seas, New Zealand Department of Conservation, Waikato Regional Council, Foundation North - GIFT and Live Ocean Foundation. </span></em></p><p class="fine-print"><em><span>Robert Smith receives funding from the New Zealand Ministry of Business Innovation and Employment.
</span></em></p>New Zealand may see more sponge bleaching as the northern coastlines are already experiencing almost continuous marine heatwave conditions, expected to extend into the coming summer.Professor James J Bell, Professor of Marine Biology, Te Herenga Waka — Victoria University of WellingtonNick Shears, Associate Professor in Marine Science, University of Auckland, Waipapa Taumata RauRobert Smith, Lecturer, University of OtagoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1932122022-10-25T19:03:32Z2022-10-25T19:03:32ZAustralia is poised to be a world leader in offshore wind, but any potential risks to marine life remain poorly regulated<figure><img src="https://images.theconversation.com/files/491530/original/file-20221025-17-bzssus.jpg?ixlib=rb-1.1.0&rect=20%2C20%2C4473%2C2970&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 strong winds blowing over Australia’s rugged coastlines will soon power many of our homes, as offshore wind farms are poised to begin construction. But our <a href="https://www.ogel.org/journal-advance-publication-article.asp?key=728">new research</a> highlights the need to ensure any potential risks to marine life is properly mitigated. </p>
<p>The federal government has recently made a string of announcements as part of its A$20 billion <a href="https://www.pm.gov.au/media/rewiring-nation-supercharge-victorian-renewables">Rewiring the Nation Plan</a>, ahead of last night’s federal budget. This includes $1.5 billion to fast-track the development of offshore wind farms and renewable energy zones in Victoria, as well as funding for the Marinus link (an electricity cable connecting Tasmania and Victoria), and pumped hydro developments.</p>
<p>By embracing what the energy world calls the “<a href="https://www.csiro.au/en/news/news-releases/2021/offshore-wind-presents-energy-advantages-as-part-of-growing-australian-blue-economy">big three</a>” – offshore wind, solar power and onshore wind power – Australia’s renewable energy exports alone could be worth <a href="https://www.climatecouncil.org.au/resources/labors-climate-bill-must-be-a-springboard-for-action/#:%7E:text=The%20economic%20opportunities%20for%20a,Australia's%20existing%20fossil%20fuel%20exports.">$333 billion</a> each year. That’s almost triple what we currently get from fossil fuels. </p>
<p>Our research calls for Australia to put marine spatial planning processes into offshore wind regulation. This considers how infrastructure and ecosystems can co-locate, by mapping out the best sites for generating the most electricity with the least environmental impact.</p>
<p>With effective regulation, Australia’s offshore wind industry can be a leader in ecologically sustainable development.</p>
<h2>Why is offshore wind important?</h2>
<p>Over the past decade, the costs to build offshore wind infrastructure have <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/">decreased by 50%</a> worldwide. It is poised to become a key ingredient in Australia’s energy mix, as the <a href="https://gwec.net/wp-content/uploads/2022/04/Annual-Wind-Report-2022_screen_final_April.pdf">Global Wind Energy Council</a> estimates a massive 4,963 gigawatts of offshore wind potential in Australia.</p>
<p>In fact, if all of Australia’s proposed offshore wind projects were built, their combined energy capacity would be <a href="https://theconversation.com/wind-turbines-off-the-coast-could-help-australia-become-an-energy-superpower-research-finds-164590">greater than</a> all Australia’s coal-fired power stations. </p>
<p>Victoria is leading the way with a target of reaching 2 gigawatts of offshore wind by 2032, and 9 gigawatts by 2040. This means some <a href="https://www.afr.com/companies/energy/australia-needs-more-offshore-wind-projects-to-lure-suppliers-20220922-p5bk6x">20% of Victoria’s energy mix</a> will come from clean, affordable and reliable offshore wind within the next ten years.</p>
<p><a href="https://arena.gov.au/renewable-energy/wind/">Despite our rich wind resources</a>, there is currently no large-scale offshore wind project operating in Australia, due to a lack of legal framework <a href="https://www.legislation.gov.au/Details/C2021A00120">that commenced operation in 2022</a>. Australia also does not currently hold a federal offshore wind target. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Wind turbine under construction" src="https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/491531/original/file-20221025-11-eyhnws.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">Underwater noise during the construction of offshore wind turbines can displace marine animals.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Australia’s lack of regulation</h2>
<p>Australia has lack of clear offshore renewable energy planning goals. This has led the <a href="https://gwec.net/wp-content/uploads/2022/04/Annual-Wind-Report-2022_screen_final_April.pdf">Global Wind Energy Council </a> to call for “a clear, transparent, and streamlined leasing and permitting process” in Australia. </p>
<p>The environmental protections currently in place are generic and need greater refinement on the needs of offshore wind. </p>
<p>Before an Australian offshore wind project can start and be granted a commercial licence, the developer must make several important assessments and proposals, including a <a href="https://www.nopsema.gov.au/offshore-renewable-energy">management plan</a>, to the Offshore Infrastructure Registrar.</p>
<p>This management plan must adhere to Australia’s national environment law, which is designed to promote ecologically sustainable development. </p>
<p>Yet, Australia’s environment law – called the <a href="https://www.legislation.gov.au/Details/C2021C00182">Environment Protection and Biodiversity Conservation (EPBC) Act</a> – has been widely criticised for failing to achieve this aim, particularly following a major <a href="https://theconversation.com/a-major-report-excoriated-australias-environment-laws-sussan-leys-response-is-confused-and-risky-154254">independent review</a> in 2021. </p>
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Read more:
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<h2>How offshore wind farms can impact marine life</h2>
<p>Marine spatial planning can provide clear ecological, social and environmental conservation objectives, while mapping important ecological zones to protect. </p>
<p>Research is still emerging on the extent offshore wind farms may impact marine ecosystems. A <a href="https://www.eionet.europa.eu/etcs/etc-icm/products/etc-icm-reports/etc-icm-report-2-2022-mapping-potential-environmental-impacts-of-offshore-renewable-energy">European Environment Agency</a> report this year points to a few potential impacts, although these are documented in Europe rather than Australia. </p>
<p>This includes underwater noise during construction, which can displace some species, cause auditory injury to nearby mammals and fish, and interfere with the echolocation of animals such as porpoises.</p>
<p>Research has also shown that during operation, some seabird species became either displaced or attracted to the turbines (though collision rates are low).</p>
<p>On the other hand, depending on its design, offshore wind turbines can provide habitat for some marine species, such as with artificial reefs on their foundations.</p>
<p>These pressures can be managed by effective marine spatial planning. Australia holds marine spatial planning processes for other areas, such as the <a href="https://www.sprep.org/attachments/Publications/articles/marine-spactial-planning-great-barrier-reef.pdf">Great Barrier Reef Marine Park</a> and parts of <a href="https://www.marineandcoasts.vic.gov.au/marine/marine-spatial-planning">Victoria</a>. </p>
<p>But we are yet to create any requirements for them in the legal framework for offshore wind at the federal level. </p>
<h2>Countries doing it better than us</h2>
<p>Several countries have enacted marine spatial planning policies and regulations for their offshore wind sectors. </p>
<p><a href="https://maritime-spatial-planning.ec.europa.eu/">The European Union</a> has led the way, as 22 <a href="https://maritime-spatial-planning.ec.europa.eu/msp-practice/countries">coastal member states</a> have adopted marine spatial planning processes. This strong policy framework has enabled the EU to reach 28.4 gigawatts of offshore wind capacity while ensuring environmental protections <a href="https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014L0089&from=EN">are in place</a>. </p>
<p>The Netherlands have an ambitious offshore wind target of 70 gigawatts by 2050. This is double what the entire EU <a href="https://www.offshorewind.biz/2022/09/19/the-netherlands-sets-70-gw-offshore-wind-target-for-2050-plans-large-scale-green-hydrogen-production-and-energy-hubs/#:%7E:text=The%20Dutch%20Government%20has%20set,could%20be%20installed%20by%202040.">has already installed</a>. </p>
<p>The Netherlands is using marine spatial planning to sustainably meet this target. It is supported by the Dutch Ecological Offshore Wind Energy Programme, which is generating <a href="https://www.noordzeeloket.nl/functies-gebruik/windenergie/ecologie/wind-zee-ecologisch-programma-wozep/newsletter-wozep/wozep-newsletter-1/wozep-research/#:%7E:text=Sitemap-,Wozep%20research%20programme%20investigates%20the%20ecological%20impact%20of%20offshore%20wind,develop%20the%20appropriate%20mitigation%20measures">baseline scientific knowledge</a> about how to protect sensitive marine environments in assessments determining new project sites. </p>
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<p>
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Read more:
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<h2>One piece of the puzzle</h2>
<p>Marine spatial planning is crucial for integrating offshore wind with other ways we use the ocean, such as for fishing and preserving traditional Sea Country. At the same time, it should preserve ecosystems and promote energy justice, where all members of society are granted access to clean energy. Marine spatial planning can strike this balance. </p>
<p>Formulating marine spatial planning objectives in consultation with the offshore wind industry, communities, and other stakeholders is crucial to ensure its success, and building an equitable ocean economy.</p>
<p><a href="https://powerup.climatecouncil.org.au/">Much more must be done</a> to ensure we continue a successful transition away from fossil fuels and avoid the worst impacts of climate change. Offshore wind is just one, exciting piece of the puzzle. </p>
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<strong>
Read more:
<a href="https://theconversation.com/3-ways-the-albanese-government-can-turn-australia-into-a-renewable-energy-superpower-without-leaving-anyone-behind-183640">3 ways the Albanese government can turn Australia into a renewable energy superpower – without leaving anyone behind</a>
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<img src="https://counter.theconversation.com/content/193212/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Madeline Taylor has received funding from ACOLA and the AIEN. She is a Climate Councillor for the Climate Council and is on the Management Committee for RE-Alliance. The author would like to acknowledge Riley Taylor and his co-authorship of the research produced.</span></em></p>Australia must map out the best sites for generating the most electricity with the least environmental impact.Madeline Taylor, Senior Lecturer, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1902212022-10-05T18:07:28Z2022-10-05T18:07:28ZClimate risk index shows threats to 90 per cent of the world’s marine species<figure><img src="https://images.theconversation.com/files/488188/original/file-20221004-14-lflwk2.jpg?ixlib=rb-1.1.0&rect=0%2C102%2C1368%2C921&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The biodiversity-rich Komodo Island in Indonesia is a climate risk hotspot.</span> <span class="attribution"><span class="source">(Daniel G. Boyce)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Climate change impacts marine life through a <a href="https://doi.org/10.1126/science.aaf7671">bewildering web of complex pathways</a>.</p>
<p>Warming oceans and climate extremes are driving species into <a href="https://doi.org/10.1126/science.1239352">deeper, more northern and cooler locations</a>, altering their <a href="https://doi.org/10.1126/science.aat4220">behaviour</a> and <a href="https://doi.org/10.1146/annurev-marine-041911-111611">reconfiguring marine ecosystems in radical and unprecedented ways</a>.</p>
<p>While some impacts can be beneficial, many are harmful, making it difficult to understand the overall effects of climate on individual species and ecosystems. Despite these challenges, we urgently need to understand how changing climate conditions affect marine life to plan and develop adaptation approaches to steward it effectively under climate change.</p>
<p>In our <a href="https://doi.org/10.1038/s41558-022-01437-y">new study,</a> my co-authors and I developed the Climate Risk Index for Biodiversity, which captures the climate risk for nearly 25,000 marine species and their ecosystems. This new index lays the groundwork for supporting climate-smart approaches to managing and conserving marine life.</p>
<h2>A climate report card</h2>
<p>We used a data-driven statistical approach to create a “climate report card” for each species and ecosystem that tells us which ones will win or lose under climate change. This approach enabled us to study a broad spectrum of life forms, from microscopic plankton to large predators and whales, across all marine ecosystems from the tropics to the poles.</p>
<figure class="align-center ">
<img alt="A whale shark swimming in the ocean." src="https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/487883/original/file-20221003-12-qsqotk.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 climate report card assessed species ranging from plankton to whales on 12 specific climate risk factors.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Just as a report card grades students on subjects such as math and science, we assessed each species on 12 specific climate risk factors depending on two different future scenarios — one with lower emissions and one with higher emissions.</p>
<p>The climate risk factors express how the innate characteristics of a species — their body size and temperature tolerance — intersect with past, present and future ocean conditions at all locations where they are found. </p>
<p>The resulting risk scale ranges from negligible (lowest) to critical (highest) and represents both the severity of harmful climate impacts on species and their likelihood of occurring.</p>
<h2>Divergent climate futures</h2>
<p>Our study focuses on two possible <a href="https://www.carbonbrief.org/explainer-how-shared-socioeconomic-pathways-explore-future-climate-change/">shared socioeconomic pathway</a> scenarios of how future society — and the greenhouse gas emissions it produces — could transpire. The results paint two wildly divergent pictures for marine life and people.</p>
<p>In the <a href="https://www.carbonbrief.org/explainer-the-high-emissions-rcp8-5-global-warming-scenario/">high emissions scenario</a>, the global average ocean temperature <a href="https://doi.org/10.5194/bg-17-3439-2020">will increase by three to five degrees Celcius</a> by 2100. Under this scenario, almost 90 per cent of the 25,000 species we assessed were at a “high” or “critical” climate risk. The average species was at risk across 85 per cent of its geographic range.</p>
<p>The risk is highest in the subtropical and tropical ecosystems that tend to be <a href="https://oceanpanel.org/publication/critical-habitats-and-biodiversity-inventory-thresholds-and-governance/">biodiversity hotspots</a> and in nearshore ecosystems that support <a href="https://doi.org/10.1038/s41586-021-03371-z">96 per cent of the global fish catch</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map showing the regions with ecosystems where marine species are at high or critical climate risk." src="https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=373&fit=crop&dpr=1 754w, https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=373&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/487932/original/file-20221003-20-tdomqz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=373&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 proportion of marine species at high or critical climate risk under high emissions by 2100. Darkest red shading denotes the highest risk areas, and darkest blue the lowest.</span>
<span class="attribution"><span class="source">(Daniel G. Boyce)</span></span>
</figcaption>
</figure>
<p>Top predators like sharks and tunas were at significantly higher risk than species further down the food chain, like forage fishes. Such predators can have <a href="https://doi.org/10.1126/science.1138657">massive effects on ecosystem structure</a> and functioning.</p>
<p>Our findings also suggest severe ripple effects for people who most rely on the ocean. Under high emissions, climate risks for fished species such as cod and lobsters were consistently greater within the territories of low-income nations, where people depend more on fisheries to meet their nutritional needs. </p>
<p>This represents yet another example of <a href="https://doi.org/10.1038/s41467-020-15708-9">climate inequality</a> wherein low-income countries that <a href="https://doi.org/10.1038/nclimate3186">have contributed the least to climate change, and are more aggressively reducing their emissions</a>, are <a href="https://doi.org/10.1038/s41467-020-15708-9">experiencing its worst impacts while having the lowest capacity to adapt to them.</a></p>
<p>Our study stresses that we are at a critical fork in the road and that choosing a more sustainable path that prioritizes climate mitigation will lead to clear benefits for ocean life and people.</p>
<p>Under a low emissions scenario, average ocean temperatures are expected to increase by <a href="https://doi.org/10.5194/bg-17-3439-2020">one to two degrees Celsius by 2100</a>, as per the two degrees Celsius global warming limit in the <a href="https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement">Paris Agreement</a>.</p>
<p>Under this future, we found a reduced climate risk for virtually all marine life (98.2 per cent). The disproportionate risk for ecosystem structure, biodiversity, fisheries and low-income nations are greatly reduced or eliminated.</p>
<h2>Averting harmful climate risks</h2>
<p>Our approaches to <a href="https://doi.org/10.1111/faf.12586">fisheries management</a>, <a href="https://doi.org/10.1126/sciadv.aay9969">protected area planning</a> and biodiversity conservation originated in a world with a relatively stable climate. But climate change is rewriting the rule books and threatening to undermine the effectiveness of these traditional approaches. </p>
<p>Cutting emissions is the most direct approach to reducing climate risks. Yet, even with strong mitigation, our study suggests that climate change will continue to affect marine life. </p>
<figure class="align-center ">
<img alt="The remains of a fish lie on the dried lake bed." src="https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486920/original/file-20220927-14-h76pgq.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">
<figcaption>
<span class="caption">In addition to reducing emissions, we must find ways to adapt to a warming climate to protect marine life and those who depend on it.</span>
<span class="attribution"><span class="source">(AP Photo/Jae C. Hong, File)</span></span>
</figcaption>
</figure>
<p>In addition to reducing emissions, it is imperative that we simultaneously find ways to adapt to a warming climate to protect our oceans. We must incorporate new methods and adaptation strategies, develop capacity in under-resourced parts of the world and carefully weigh the pros and cons of adaptation measures.</p>
<p>Our study provides a new tool and index to help inform decision-makers when navigating these complex issues. It can assist with developing strategies to manage and conserve marine life under climate change, monitor changing climate risk and gauge progress towards risk reduction.</p>
<p>While our study paints a potentially grim future under high emissions, it also highlights how our oceans and marine life could benefit from climate change mitigation and adaptation and stresses the urgency with which we must work towards this goal.</p><img src="https://counter.theconversation.com/content/190221/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel G. Boyce 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>A new biodiversity index captures the climate risk for nearly 25,000 marine species and their ecosystems and lays the groundwork for climate-smart approaches to management and conservation.Daniel G. Boyce, Research Scientist, Bedford Institute of Oceanography, Fisheries and Oceans Canada, Adjunct Professor, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1913402022-09-27T06:06:12Z2022-09-27T06:06:12ZAbout 200 dead whales have been towed out to sea off Tasmania – and what happens next is a true marvel of nature<figure><img src="https://images.theconversation.com/files/486684/original/file-20220927-14-7mqf23.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4025%2C3024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Department of Natural Resources and Environment Tasmania </span></span></figcaption></figure><p>Australians watched in horror last week as 230 pilot whales became stranded at a beach near Macquarie Harbour on Tasmania’s west coast. Some whales were saved, but the vast majority died. This left a big problem: what to do with all the rotting whale carcasses?</p>
<p>Authorities decided to tow the dead animals out to sea, hoping they’ll eventually sink to the seafloor. </p>
<p>Such mass whale strandings are sad to witness. But in this case, the aftermath presents a fascinating opportunity for scientific discovery. </p>
<p>As the dead whales decompose, an astonishing and rare chain of events is likely to flow through the marine ecosystem – ultimately leading to an explosion of activity and new life.</p>
<figure class="align-center ">
<img alt="aerial view of beach with whales stranded in line" src="https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486685/original/file-20220927-16-b7es39.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">Authorities decided to tow the dead animals out to sea, hoping they’ll eventually sink to the seafloor.</span>
<span class="attribution"><span class="source">Department of Natural Resources and Environment Tasmania</span></span>
</figcaption>
</figure>
<h2>A 600-tonne problem</h2>
<p>Mass whale strandings happen fairly regularly – especially in Tasmania – yet no one really knows why.</p>
<p>Days before this latest incident, <a href="https://www.abc.net.au/news/2022-09-20/sperm-whales-stranded-off-king-island-tasmania/101457406">14 sperm whales</a> became stranded off King Island, northwest of Tasmania.</p>
<p>And in 2020, about 470 pilot whales <a href="https://theconversation.com/like-trying-to-find-the-door-in-a-dark-room-while-hearing-your-relatives-scream-for-help-tasmanias-whale-stranding-tragedy-explained-146674">became stranded</a> at Macquarie Harbour. While many were pulled out to sea, some of those carcasses washed up and were left to rot on the beach – an entirely natural process. </p>
<p>However, pilot whales are big animals. Males weigh up to 2,300kg, which means they take a long time to decompose. The smell of two tonnes of rotting whale blubber soon becomes unbearable, so carcasses are frequently buried. </p>
<p>This time around, authorities <a href="https://www.abc.net.au/news/2022-09-25/whale-carcasses-towed-out-to-sea-after-mass-stranding/101471166">decided to tow</a> the dead animals out to sea. The ABC reported local salmon farm workers took almost 11 hours to dispose of 204 dead whales with a combined weight of between 500 and 600 tonnes.</p>
<p>They were tied to a 400 metre-long rope and towed by boats for 40 kilometres, before being dropped into deep water in the Indian Ocean.</p>
<p>Some carcasses may wash back to shore, but most are likely to disperse with the tides and currents. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-dont-whales-have-teeth-like-we-do-186727">Curious kids: why don’t whales have teeth like we do?</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Two men in high-vis stand in front of tractor and trailer carrying a whale" src="https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486686/original/file-20220927-12-he77l6.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">Mass whale strandings happen fairly regularly, yet no one really knows why.</span>
<span class="attribution"><span class="source">Department of Natural Resources and Environment Tasmania</span></span>
</figcaption>
</figure>
<h2>Shark bait? Probably not</h2>
<p>The big question is: what happens to all that whale mass dumped at sea?</p>
<p>Initially, a dead whale tends to float to the surface as it begins to decompose and its innards expand with gas. As this happens, ocean scavengers such as sharks and seabirds are likely to feast on the remains.</p>
<p>Some people <a href="https://www.abc.net.au/news/2019-04-14/do-buried-whale-carcasses-really-attract-sharks/10996512">can be concerned</a> that whale carcasses attract sharks that might pose a risk to humans. </p>
<p>Granted, encounters between sharks and humans, are <a href="https://theconversation.com/fatal-shark-attacks-are-at-a-record-high-deterrent-devices-can-help-but-some-may-be-nothing-but-snake-oil-150845">on the rise</a> in Australia and elsewhere. But they’re still very rare. </p>
<p>A <a href="https://parks.des.qld.gov.au/__data/assets/pdf_file/0024/167613/swim-humpback-whales-risks-sharks.pdf">report</a> to the Western Australian government in 2012 found whale carcasses were a risk factors associated with shark attacks, and said caution should be exercised near a dead whale in the water.</p>
<p>But the same report noted that of 26 shark attacks investigated, the highest number occurred more than a kilometre offshore. While there is no doubt <a href="https://doi.org/10.1016/j.gecco.2019.e00655">sharks are attracted to dead whales</a>, the data is <a href="https://hakaimagazine.com/news/beached-whales-are-a-lure-for-hungry-sharks/">not clear</a> on whether a whale carcass leads directly to an increase in shark attacks on people. </p>
<p>Research <a href="https://www.sciencedirect.com/science/article/pii/S2351989419301854?via%3Dihub">has shown</a> the likelihood of whale carcasses washing towards shore, where shark scavenging can be observed, is low. So as long as the carcass is taken far from shore and people keep their distance from it, the threat to humans from shark encounters appears to be exceedingly low. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-whales-keep-getting-tangled-in-shark-nets-and-what-should-you-do-if-you-see-it-happen-186468">Why do whales keep getting tangled in shark nets? And what should you do if you see it happen?</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Rescue boat next to the carcass of a large white whale" src="https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486688/original/file-20220927-27-owyv43.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dead floating whales provide a feast for animal scavengers. Pictured: seabirds feed on a large whale carcass floating off Spain in 2018.</span>
<span class="attribution"><span class="source">EFE/SASEMAR</span></span>
</figcaption>
</figure>
<h2>From death comes new life</h2>
<p>Inevitably, the whale carcass will start to sink. Most life in the ocean is found fairly close to the sea surface, so if the water is relatively shallow much of what’s left of the carcass will be quickly eaten by scavengers once it reaches the sea floor. </p>
<p>But these carcasses have been disposed of in deep water. The deep ocean can be a barren place, where rich food sources are rare. So the appearance of a single whale carcass can supercharge an entire ecosystem. </p>
<p>New life and activity can erupt around the dead animal in very little time. This process is known as “whale fall” and has been studied by scientists, sometimes using remotely operated vehicles. On the seafloor of the North Pacific, whale fall has been found to <a href="https://www.frontiersin.org/articles/10.3389/fevo.2022.885572/full">support the survival</a> of at least 12,490 organisms of 43 species. </p>
<p>Deep sea sharks will make the most of the carcass. <a href="https://www.youtube.com/watch?v=CZzQhiNQXxU">A host of other animals</a> including hagfish, octopus, crabs, lobsters, worms and sea cucumbers will join in too. All the while bacteria work away quietly in the background. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-migaloo-dead-as-climate-change-transforms-the-ocean-the-iconic-white-humpback-has-been-missing-for-two-years-184256">Is Migaloo ... dead? As climate change transforms the ocean, the iconic white humpback has been missing for two years</a>
</strong>
</em>
</p>
<hr>
<p><a href="https://www.nhm.ac.uk/discover/what-happens-when-whales-die.html">According to</a> Britain’s Natural History Museum, a single whale can provide animals with food for up to two years during the scavenging stage. </p>
<p>Other animals and bacteria survive off the chemicals produced from the rotting carcass.</p>
<p>These organisms, known as “chemotrophs” were thought to be unique to underwater volcanic vents, where they use hydrogen sulphide as the principal energy source. <a href="https://doi.org/10.1098/rspb.2016.2337">Research</a> has shown a similar suite of animals recruit around dead and decaying whales – generating a completely independent ecosystem based on a gas that <a href="https://www.nhm.ac.uk/discover/what-happens-when-whales-die.html">smells like rotten eggs</a>.</p>
<p>Only a few organisms can break down the bones that remain, in a process that might take up to ten years. </p>
<p>So take a moment to consider the effect of 204 whale falls in a small part of the ocean off Tasmania. Right now, they are probably generating interconnected marine metropolises, the likes of which are rarely seen.</p><img src="https://counter.theconversation.com/content/191340/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Culum Brown receives funding from Australian Research Council, Taronga Zoo, Sea World Research and Rescue Foundation</span></em></p>As the dead whales decompose, an astonishing and rare chain of events is likely to flow through the marine ecosystem – ultimately leading to an explosion of activity and new life.Culum Brown, Professor, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1892312022-08-28T20:04:50Z2022-08-28T20:04:50ZThousands of photos captured by everyday Australians reveal the secrets of our marine life as oceans warm<figure><img src="https://images.theconversation.com/files/481238/original/file-20220826-8211-tauikk.jpg?ixlib=rb-1.1.0&rect=160%2C5%2C1459%2C818&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.redmap.org.au/sightings/3798/">Redmap/Jacob Bradbury</a></span></figcaption></figure><p>As the planet heats up, many marine plants and animals are <a href="https://theconversation.com/climate-driven-species-on-the-move-are-changing-almost-everything-74752">moving</a> locations to keep pace with their preferred temperatures. In the Southern Hemisphere, this means species are setting up home further south.</p>
<p>This shift alters what we see when we go snorkelling, and when and where we catch our seafood. Crucially, it also changes sensitive marine ecosystems. </p>
<p>But it’s not always easy for scientists to know exactly what’s happening below the ocean’s surface. To help tackle this, we examined tens of thousands of photographs taken by Australian fishers and divers submitted to citizen science programs over the last decade. </p>
<p>They revealed climate change is already disrupting the structure and function of our marine ecosystems – sometimes in ways previously unknown to marine scientists.</p>
<figure class="align-center ">
<img alt="man holds large silver fish" src="https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&rect=2%2C2%2C1914%2C1074&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481235/original/file-20220826-18-8j5rl4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The authors examined tens of thousands of photographs taken by Australian fishers and divers, such as this image of a bonefish found off Western Australia.</span>
<span class="attribution"><span class="source">Redmap</span></span>
</figcaption>
</figure>
<h2>Species on the move</h2>
<p>Warming over the Pacific Ocean has strengthened the East Australian Current over the past several decades, as the below-right animation shows. This has caused waters off Southeast Australia to warm at almost <a href="https://link.springer.com/article/10.1007/s11160-013-9326-6">four times</a> the global average. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Animated map of sea surface temperatures in southeast Australia from 2004 to 2022" src="https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480969/original/file-20220824-14-i52yob.gif?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">Animated map of sea surface temperatures in southeast Australia from 2004 to 2022. Data sourced from NASA.</span>
<span class="attribution"><span class="source">Barrett Wolfe</span></span>
</figcaption>
</figure>
<p>There is already irrefutable evidence <a href="https://www.science.org/doi/10.1126/science.aai9214">climate change</a> is causing marine species <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15634">to move</a>. Understanding this phenomenon is crucial for conservation, fisheries management and human health. </p>
<p>For example, if fish susceptible to carrying <a href="https://www.redmap.org.au/news/2020/12/10/ciguatera-fish-poisoning/">toxins</a> start turning up where you go fishing, you’d want to know. And if an endangered species moves somewhere new, we need to know so we can protect it.</p>
<p>But the <a href="https://www.ga.gov.au/scientific-topics/marine/coasts-estuaries#:%7E:text=The%20Australian%20coastline%20extends%20approximately,includes%20more%20than%201000%20estuaries.">sheer scale</a> of the Australian coastline means scientists can’t monitor changes in all areas. That’s where the public can help. </p>
<p>Fishers, snorkelers and divers often routinely visit the same place over time. Many develop strong knowledge of species found in a given area. </p>
<p>When a new or unusual species appears in their patch, these members of the public can excel at detecting it. So our project set out to tap into this invaluable community knowledge.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-driven-species-on-the-move-are-changing-almost-everything-74752">Climate-driven species on the move are changing (almost) everything</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="large fish and smaller fish on blue marine background" src="https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481221/original/file-20220826-8211-tw4ry1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This sighting of a sea sweep – recorded in May this year off Kangaroo Island by a member of the public – may indicate the species is extending its range.</span>
<span class="attribution"><span class="source">Redmap/Daniel Easton</span></span>
</figcaption>
</figure>
<h2>The value of citizen science</h2>
<p>The <a href="https://www.redmap.org.au/">Redmap</a> citizen science project began in Tasmania in 2009 and went national in 2012. It invites the public to share sightings of marine species uncommon in their area. </p>
<p>Redmap stands for Range Extension Database and Mapping project. Redmap members use their local knowledge to help monitor Australia’s vast coastline. When something unusual for a given location is spotted, fishers and divers can upload a photo with location and size information. </p>
<p>The photos are then verified by a <a href="https://www.redmap.org.au/about/meet-the-scientists/">network</a> of almost 100 marine scientists around Australia. Single observations cannot tell us much. But over time, the data can be used to map which species may be extending their range further south.</p>
<p>The project is supported by the University of Tasmania’s <a href="https://www.imas.utas.edu.au/">Institute for Marine and Antarctic Studies</a>, together with other Australian universities and a range of Commonwealth and state-government bodies.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/warming-oceans-are-changing-australias-fishing-industry-98301">Warming oceans are changing Australia's fishing industry</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481220/original/file-20220826-12-dh55qg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Screenshot of the Redmap website highlighting a recent coral sighting.</span>
<span class="attribution"><span class="source">Redmap</span></span>
</figcaption>
</figure>
<p>We also examined data from two other national marine citizen science programs: <a href="https://reeflifesurvey.com/">Reef Life Survey</a> and <a href="https://www.inaturalist.org/projects/australasian-fishes">iNaturalist Australasian Fishes Project</a>. The resulting dataset encompassed ten years of photographed species observations made by almost 500 fishers, divers, snorkelers, spearfishers and beachcombers.</p>
<p>The citizen scientists recorded 77 species further south than where they lived a decade ago. Many were observed at their new location over multiple years and even in cooler months. </p>
<p>For example, spearfisher Derrick Cruz got a surprise in 2015 when he saw a coral trout swimming through a temperate kelp forest in his local waters off Sydney, much further south than he’d seen before. He submitted the below photo to Redmap, which was then verified by a scientist.</p>
<figure class="align-center ">
<img alt="Man snorkeling in the ocean, holding up a large orange fish" src="https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480719/original/file-20220824-22-qpj3ls.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spearfisher Derrick Cruz, pictured with a coral trout off Sydney.</span>
<span class="attribution"><span class="source">Redmap</span></span>
</figcaption>
</figure>
<p>Citizen scientists using Redmap were also the first to spot the <a href="https://www.redmap.org.au/sightings/566/">gloomy octopus</a> off Tasmania in 2012. Subsequent <a href="https://www.abc.net.au/news/2018-06-28/gloomy-octopus-migrating-to-tasmania-due-to-climate-warming/9919122">genetic studies</a> confirmed the species’ rapid extension into Tasmanian waters. </p>
<p>Similarly, solo eastern rock lobsters have been turning up in Tasmania for some time. But Redmap <a href="https://www.redmap.org.au/sightings/522/">sightings</a> recorded dozens of individuals living together in a “den”, which had not been observed previously.</p>
<p>Other species recorded by citizen scientists moving south include the <a href="https://www.redmap.org.au/sightings/3465/">spine-cheek clownfish</a>, Moorish idol and <a href="https://www.redmap.org.au/sightings/4248/">tiger sharks</a>.</p>
<h2>Supporting healthy oceans</h2>
<p>Using the citizen science data, we produced a <a href="https://www.redmap.org.au/media/uploads/2022/08/08/redmap-report-card-project-nesp-report-draft.pdf">report</a> outlining the assessment methods underpinning our study. We’ve also produced detailed state-based report cards for Western Australia, Tasmania and New South Wales, where coastal waters are warming much faster than the global average.</p>
<p>We also generated a map of the species shifts this revealed, and a downloadable <a href="https://www.redmap.org.au/article/report-card/">poster</a> summarising the findings. This allows the public – including those who contributed data – to see at a glance how climate change is affecting our oceans. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of Australia with southerly lines around the coastline depicting how species distributions have shifted over the last decade" src="https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=576&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=576&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480858/original/file-20220824-14-p217nk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=576&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Left, a downloadable poster summarising the species shifts in distribution. Right, the state-based report cards.</span>
</figcaption>
</figure>
<p>Citizen science has benefits beyond helping us understand changes in natural systems. Projects such as Redmap open up a community conversation about the impacts of climate change in Australia’s marine environment - using the public’s own knowledge and photos.</p>
<p>Our research <a href="https://www.sciencedirect.com/science/article/pii/S0964569117305665">suggests</a> this method engages the community and helps get people involved in documenting and understanding the problems facing our oceans and coasts. </p>
<p>A better understanding – by both scientists and the public – will help ensure healthy ecosystems, strong conservation and thriving fisheries in future. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-you-can-help-scientists-track-how-marine-life-reacts-to-climate-change-33370">How you can help scientists track how marine life reacts to climate change</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/189231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gretta Pecl receives funding from the Australian Research Council (ARC), the Fisheries Research & Development Corporation (FRDC), the Department of Agriculture Water and the Environment through the National Environmental Science Program (NESP), and the Department of Primary Industries NSW. She is also a Lead Author on the recent IPCC assessment report, and received funding from the Department of Environment and Energy to support travel to IPCC meetings. </span></em></p><p class="fine-print"><em><span>Barrett Wolfe receives funding from the Fisheries Research and Development Corporation, the Department of Agriculture Water and the Environment through the National Environmental Science Program, Department of Primary Industries NSW and NRE Tasmania. He has received past research funding from Seaworld Research and Rescue Foundation and PADI Foundation.</span></em></p><p class="fine-print"><em><span>Curtis Champion receives funding from the Fisheries Research and Development Corporation. He works for the NSW Department of Primary Industries.</span></em></p><p class="fine-print"><em><span>Jan Strugnell receives funding from the Australian Research Council (ARC), the Fisheries Research and Development Corporation (FRDC), the Department of Agriculture Water and the Environment through the National Environmental Science Program (NESP) and the Queensland Government through the Queensland Citizen Science Grants.</span></em></p><p class="fine-print"><em><span>Sue-Ann Watson receives funding from the Australian Research Council (ARC), the Department of Agriculture Water and the Environment through the National Environmental Science Program (NESP) and Queensland Government through the Queensland Citizen Science Grants. </span></em></p>The photographs show how climate change is disrupting our marine ecosystems – sometimes in ways previously unknown to marine scientists.Gretta Pecl, Professor, ARC Future Fellow & Director of the Centre for Marine Socioecology, University of TasmaniaBarrett Wolfe, Postdoctoral Research Fellow, University of TasmaniaCurtis Champion, Research Scientist, Southern Cross UniversityJan Strugnell, Professor Marine Biology and Aquaculture, James Cook UniversitySue-Ann Watson, Senior Research Fellow, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1827492022-05-24T18:16:35Z2022-05-24T18:16:35ZThe future of fishing and fish — and the health of the ocean — hinges on economics and the idea of ‘infinity fish’<figure><img src="https://images.theconversation.com/files/465070/original/file-20220524-22-jw6gdn.jpg?ixlib=rb-1.1.0&rect=59%2C59%2C4932%2C3270&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fish stocks are in decline around the world, in part because of the way we value nature and fail to account for their long-term benefits. </span> <span class="attribution"><span class="source">(Shutterstock)</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/the-future-of-fishing-and-fish-—-and-the-health-of-the-ocean-—-hinges-on-economics-and-the-idea-of--infinity-fish-" width="100%" height="400"></iframe>
<p><em>Editor’s note: This story is part of a series that also includes live interviews with some of Canada’s top social sciences and humanities academics. Click <a href="https://www.meetview.ca/sshrc20220525/">here</a> to register for this free event, on May 25, at 1 p.m. EDT, co-sponsored by The Conversation and the Social Sciences and Humanities Research Council.</em></p>
<p><a href="https://doi.org/10.1139/facets-2021-0089">Indigenous Elders recently shared their dismay about the unprecedented decline in salmon populations</a> in British Columbia’s three largest salmon-producing rivers. Research produced by my team found that the Coho salmon catch off the southern B.C. coast has declined to only about <a href="https://doi.org/10.1016/j.fishres.2019.04.002">five per cent of the peak catch</a>, which dates back to the early 1900s. </p>
<p>The decrease in <a href="https://www.eea.europa.eu/help/glossary/eea-glossary/fish-stock">fish stocks</a> is a global problem. <a href="https://www.thecanadianencyclopedia.ca/en/article/cod-moratorium-of-1992">Cod stocks off Newfoundland</a>, <a href="https://allafrica.com/stories/201709070732.html">pilchard along the coast of Namibia</a>, <a href="https://doi.org/10.1002/ece3.8336">spring-spawning herring off Norway</a> and <a href="https://usa.oceana.org/responsible-fishing-modern-day-pacific-sardine-collapse-how-prevent-future-crisis/">sardines off California</a> have all collapsed in the past five decades or so. Globally, more than 100 million tonnes of fish are plucked from the ocean each year, equivalent to over 100 million mature cows in weight! </p>
<p>According to the United Nations Food and Agricultural Organization (FAO), 34 per cent of the world’s fish stocks are overfished. But other organizations, including the <a href="https://www.minderoo.org/global-fishing-index/">Global Fish Index</a>, estimate that roughly half of marine fish stocks are overexploited. </p>
<p>These depletions are partly due to the way we value — or rather don’t value — nature. The inappropriate valuation of the goods and services nature provides us with is a fundamental reason why we have failed to take good care of the ocean and the environment at large. It is undermining humankind’s ability to achieve what I call “<a href="https://infinity.fish/">infinity fish</a>”: passing on a healthy ocean to our children and grandchildren so they too can have the option to do the same.</p>
<h2>The price isn’t right</h2>
<p>When it comes to fish, some economists say all will be fine if we just get “the price right.” I say get the value and valuation right and we will be in a better position to live in harmony with nature. Assigning the correct value to fish will help societies assess the long-term cost of depleting the ocean of too many fish, too quickly, in too many parts of the ocean. </p>
<figure class="align-center ">
<img alt="A person standing in a small boat throws a fishing net into the ocean." src="https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465066/original/file-20220524-18-uqnga6.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">More than 80 per cent of global fisheries subsidies go to large-scale industrial fishing fleets.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Marine fisheries are <a href="https://doi.org/10.1038/s41467-021-23168-y">vital for the livelihoods of tens of millions of people worldwide</a>. They contribute directly and indirectly to the <a href="https://doi.org/10.1007/s10818-010-9090-9">food and nutritional security</a> of billions by delivering seafood and generating tens of millions of jobs and incomes, especially in the least developed coastal countries of the world, where the ocean supplies up to 20 per cent of the animal protein people consume.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ocean-warming-is-changing-the-relationship-coastal-communities-have-with-the-ocean-122599">Ocean warming is changing the relationship coastal communities have with the ocean</a>
</strong>
</em>
</p>
<hr>
<p>Wild fish stocks are a renewable resource that can continue to provide food and livelihoods to people forever — if they’re used wisely. Mathematically, anything that continues to provide a positive gain, no matter how small, will add up to infinity. </p>
<p>No one wants a dead ocean. To avoid that, we need to adopt an infinity fish way of thinking: a proper and complete valuation of the full range of the ocean’s benefits — seafood, carbon sequestration, recreation, culture, heat absorption — beyond what we sell in the market. </p>
<h2>Discounting nature away</h2>
<p>A key challenge to economics is how to value benefits from marine ecosystems in a comprehensive manner and in a way that captures their long-term diverse values. We have to meet this challenge if we are to have any chance of achieving infinity fish. </p>
<p>A key obstacle to achieving infinity fish is that, as humans, we tend to view anything close to us, both temporally and spatially, as large and weighty, while we give little or no importance to anything more distant. This tendency, which is partly captured by the <a href="https://doi.org/10.1093/oxfordjournals.cje.a013636">economic concept of discounting</a>, has been a big stumbling block to our ability to live in <a href="https://doi.org/10.1016/j.ecolecon.2003.11.012">harmony with nature</a>.</p>
<p>Essentially, discounting, which reduces benefits to be received in the future to its value today, makes us want to frontload our benefits and backload our costs. This tendency partly explains why <a href="https://doi.org/10.5281/zenodo.6417333">we continue to overexploit biodiversity</a> and <a href="https://doi.org/10.1126/science.1059199">deplete marine</a> <a href="https://doi.org/10.1038/nature01017">fish stocks</a> in particular. It also partly explains why we keep <a href="http://users.telenet.be/j.janssens/CommentsSPM4web.pdf">polluting the environment with carbon dioxide</a> <a href="https://doi.org/10.1093/reep/rez007">and plastic</a>.</p>
<figure class="align-center ">
<img alt="Aerial view of fishing trawlers in the ocean." src="https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465067/original/file-20220524-12-x9cg52.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Closing the high seas to fishing would have an immense positive effect on fish stocks.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Once individuals, communities and societies calculate the true values, we will be able to develop the guiding principles we need to live in harmony with nature. It would motivate us to: </p>
<ul>
<li>effectively <a href="https://doi.org/10.1080/00358533.2012.661532">manage fish stocks</a>;</li>
<li>deal with the <a href="https://doi.org/10.3354/meps11135">drivers of overfishing</a>;</li>
<li>eliminate or redirect <a href="https://doi.org/10.1126/science.abm1680">harmful fisheries subsidies</a>;</li>
<li>rebuild and restore <a href="http://kenyacurrent.com/wp-content/uploads/2017/03/SunkenBillionsRevisited-embargoed14Feb17.pdf">depleted fish stocks</a>;</li>
<li>avoid <a href="https://doi.org/10.1139/f2011-171">oil spills</a> and marine plastic pollution;</li>
<li>eliminate <a href="https://doi.org/10.1126/sciadv.aaz3801">illegal and illicit trade in fish catch</a>;</li>
<li><a href="https://doi.org/10.1038/srep08481">close the high seas</a> (areas beyond national jurisdiction) to fishing;</li>
<li>treat climate change as <a href="https://elischolar.library.yale.edu/cgi/viewcontent.cgi?article=1019&context=fes-pubs">the crisis that it is</a>.</li>
</ul>
<p>Ultimately, we need to avoid harmful policies that encourage negative actions by people on nature, such as handing <a href="https://doi.org/10.3389/fmars.2020.539214">more than 80 per cent of global fisheries subsidies to large-scale industrial fishing fleets</a>, to the disadvantage of small-scale coastal fishers, including artisanal and subsistence fisheries. </p>
<hr>
<p>
<em>
<strong>
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>
</strong>
</em>
</p>
<hr>
<h2>Future generations</h2>
<p>From the ocean, good things come, and to the ocean, bad things go. </p>
<p>People take what they want or need from the ocean, pulling those goods into our economic, cultural and social systems. In turn, we generate lots of waste, including greenhouse gases, which are absorbed by the ocean and increase sea surface temperatures, raise sea levels and boost ocean acidity, among other negative impacts.</p>
<figure class="align-center ">
<img alt="Three people carrying two nets of fish on the beach between them." src="https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465069/original/file-20220524-13-77qtj5.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">
<figcaption>
<span class="caption">Achieving ‘infinity fish’ would allow us to pass on a healthy ocean to our children and grandchildren.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Clearly, we must take the good things from the ocean more wisely and within the limits of nature, while reducing the pollution that reaches the ocean to the barest minimum. We must also ensure that what we take out of the ocean is used to meet the
needs of as many people as possible, especially, the most vulnerable among us.</p>
<p>To achieve infinity fish, we need an interdisciplinary approach, founded on partnerships that allow scientists, Indigenous Peoples, governments, businesses, NGOs and civil society to co-create solutions. </p>
<p>The ocean is huge: it covers 70 per cent of the Earth’s surface. But it is not too big to protect — we have the brains and empathy needed to collectively ensure we achieve infinity fish for future generations. We just need to get the values and valuations right. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464583/original/file-20220520-18-x2dwff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="https://www.meetview.ca/sshrc20220525/">Click here to register for In Conversation With Rashid Sumaila.</a></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/182749/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rashid Sumaila receives funding from SSHRC, NSERC, the Pew Charitable Trusts, Oceana. In addition to the University of British Columbia, he is affiliated with National University of Malaysia as a Distinguished International Professor. </span></em></p>Humans have failed to take good care of the ocean — and the environment at large — because we undervalue its goods and services.Rashid Sumaila, Director & Professor, Fisheries Economics Research Unit, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1822052022-05-16T17:57:40Z2022-05-16T17:57:40ZClimate change is now on the menu at seafood restaurants<figure><img src="https://images.theconversation.com/files/462902/original/file-20220512-22-fd3ssw.jpg?ixlib=rb-1.1.0&rect=30%2C90%2C6679%2C4124&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Warmer-water preferring fish species like sardines and squid may soon dominate seafood menus on the west coast of Canada. </span> <span class="attribution"><span class="source">(Shutterstock)</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-now-on-the-menu-at-seafood-restaurants" width="100%" height="400"></iframe>
<p>Restaurant menus across the West Coast of Canada will soon see an influx of squid and sardine dishes, while the popular sockeye salmon makes a slow exit. As it turns out, <a href="https://news.ubc.ca/2022/04/21/vancouver-restaurant-menu-squid-sockeye-salmon/">climate change may have something to do with this</a>.</p>
<p>Restaurants update their menus all the time and this often goes unnoticed by diners. These changes are driven by culinary trends, consumer preferences and many environmental and socio-economic factors that affect the availability of the ingredients. According to <a href="https://doi.org/10.1007/s10641-022-01244-6">a recent study</a> published by my research team, we can now add climate change to this list. </p>
<p>We found that as the ocean temperature rises, many marine fish and shellfish move from their traditional habitats towards the North and South Poles in search of cooler waters. This movement of fish stocks affects the availability of seafood catch, compelling chefs to rewrite the menus of seafood restaurants on the West Coast of Canada.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/species-on-the-move-4-ways-conservation-can-adapt-in-an-era-of-climate-change-179254">Species on the move: 4 ways conservation can adapt in an era of climate change</a>
</strong>
</em>
</p>
<hr>
<h2>Climate change affects our ocean and fisheries</h2>
<p>The latest report from the UN’s <a href="https://www.ipcc.ch/report/ar6/wg2/">Intergovernmental Panel on Climate Change</a> confirmed that climate change is impacting the ocean, fish stocks and fisheries through ocean warming, loss of sea ice, <a href="https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification">ocean acidification</a>, heatwaves, <a href="https://www.iucn.org/theme/marine-and-polar/our-work/climate-change-and-oceans/ocean-deoxygenation">ocean deoxygenation</a> and other <a href="https://www.ipcc.ch/srocc/">extreme weather events</a>.</p>
<figure class="align-center ">
<img alt="Underwater bleached white corals surrounded by fish." src="https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463076/original/file-20220513-24-cnheuf.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">Fish stocks are affected by ocean warming, acidification, loss of sea ice and many other effects of climate change.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The impacts of warming-induced ecological shifts are also seen in our fisheries. Fish catches around the world are increasingly dominated by <a href="https://doi.org/10.1038/nature12156">species that prefer warmer water</a>.</p>
<p>We applied an index called “mean temperature of catch” to measure such changes in species of fish caught along the West Coast of Canada, and found that the catch of warmer-water species in this region has increased from 1961 to 2016. </p>
<h2>Relating seafood on menus to climate change</h2>
<p>But how exactly do these changes in fisheries catch dictate the food that appears in our plates? <a href="https://news.ubc.ca/tag/john-paul-ng/">My co-author John-Paul Ng</a> and I decided to tackle this question ourselves by focusing our efforts on the West Coast of Canada and the U.S. where many restaurants serve seafood.</p>
<p>We looked at present-day menus from restaurants in these areas, along with menus — some dating back to the 19th century — taken from historical archives in city halls and local museums. </p>
<figure class="align-center ">
<img alt="A restaurant menu from 1888" src="https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463081/original/file-20220514-21-ipvlc5.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">Caption Hotel Vancouver 1888 dinner menu. Restaurant menus show the seafood selection at different periods in time.</span>
<span class="attribution"><span class="source">(City of Vancouver Archives, AM1519-PAM 1888-17)</span></span>
</figcaption>
</figure>
<p>After looking at 362 menus, we used a similar approach to the one we developed to study fisheries catches and calculated a “<a href="https://doi.org/10.1007/s10641-022-01244-6">mean temperature of restaurant seafood</a>.” This index represents the average preferred temperature across all seafood species that appeared on the sampled menus from restaurants in a city for a specific time period. This index is a tool to help us gauge whether our restaurants are serving more or less warm and cold water seafood. </p>
<p>We found that the average preferred water temperature of fish and shellfish appeared in our menu increased to 14 C in recent times (2019-21) from 9 C in 1961-90 period. </p>
<p>This increase in the preferred water temperature of fish on restaurant menus is connected to changes in sea water temperature and the temperature-related changes in the composition of fish species caught during the same time period.</p>
<h2>More squid and sardine dishes</h2>
<p>Ocean warming is starting to change the variety of seafood available. </p>
<p>Driven by the higher ocean temperature in the northeast Pacific Ocean, <a href="https://doi.org/10.1073/pnas.0702043104">the Humboldt squid — a large, predatory squid species</a> that inhabits the eastern Pacific Ocean — is now making more frequent appearances on present-day restaurant menus in Vancouver.</p>
<p>British Columbia once had a commercially important Pacific sardine fishery, which was a common restaurant seafood. After the fishery collapsed in the <a href="https://doi.org/10.1139/f94-048">mid-1940s</a>, the fish seldom appeared in our sampled restaurant menus.</p>
<figure class="align-center ">
<img alt="A school of fish in the ocean water." src="https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463080/original/file-20220514-26-1fd1kh.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">Research shows that sardines will soon become more abundant in B.C. waters.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>According to research conducted by colleagues in <a href="https://doi.org/10.1371/journal.pone.0196127">fisheries research</a> and <a href="https://doi.org/10.1371/journal.pone.0145285">by our team at the Institute for the Oceans and Fisheries</a>, the sardines, which prefer warmer water, will soon make a big comeback on the West Coast of Canada. We expect that more sardine dishes will start appearing on the menus of restaurants here.</p>
<h2>Responding to changing seafood availability</h2>
<p>Globalization and the diversification of cuisines have brought a wider array of seafood options to coastal cities such as Vancouver and Los Angeles. Imported and farmed <a href="https://doi.org/10.1016/j.jcomm.2017.12.004">seafood are increasingly common ingredients in menus</a>.</p>
<p>As climate change continues to shuffle species’ distribution in ocean waters, we expect that climate-induced changes to seafood menus at restaurants will become even more pronounced. </p>
<p>Our study on restaurant menus underscores the <a href="https://www.downtoearth.org.in/news/climate-change/climate-crisis-may-destroy-aquatic-food-systems-and-livelihoods-economies-79066">wide-ranging impacts of climate change on our food system</a>. In cases where alternative seafood ingredients are available and consumer preferences are flexible, the impacts on our social, economic and cultural well-being may be limited. However, substantial <a href="https://www.vancity.com/viewport/mobile/SharedContent/documents/pdfs/News/Vancity-Report-Impact-of-Climate-Change-on-Seafood-in-BC-2015.pdf">negative consequences</a> are likely to be felt by many vulnerable communities that do not have the capacity to adapt to such changes. </p>
<p>Global and local actions to support both climate change adaptation and mitigation are essential if we want the ocean to continue to provide food for the people around the world who rely on it for nutritional security.</p><img src="https://counter.theconversation.com/content/182205/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>William W. L. Cheung receives funding from NSERC, SSHRC, CIHR, and the David and Lucile Packard Foundation.</span></em></p>As the ocean temperature rises, many marine species are moving toward the north and south poles in search of cooler waters, thus rewriting the menus of seafood restaurants on the West Coast of Canada.William W. L. Cheung, Professor and Director, Institute for the Oceans and Fisheries, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1778952022-04-21T19:43:55Z2022-04-21T19:43:55ZCanada’s marine conservation toolbox needs an overhaul to counter climate change<p>The impacts of climate change are becoming increasingly pervasive, bringing Canada’s lack of preparedness in its marine conservation measures into focus.</p>
<p>The North Atlantic right whales — <a href="https://www.worldwildlife.org/species/north-atlantic-right-whale">one of the most endangered large whales</a> found off the eastern shores of Canada — are now changing their habits and traditions.</p>
<p>Their pursuit of their favourite food source — small and nutritious crustaceans — has taken them further north from the Bay of Fundy to <a href="https://www.cbc.ca/news/canada/new-brunswick/north-atlantic-right-whale-climate-change-1.6163574">new feeding grounds in the waters of the Gulf of St. Lawrence</a> in recent years. This migration effectively renders the <a href="https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/recovery-strategies/north-atlantic-right-whale-proposed/chapter-11.html">existing conservation area in the Bay of Fundy</a> to protect the highly threatened population useless. </p>
<p>To address these increasingly pervasive, climate-driven changes, we, a collaboration between conservation research and marine governance professionals from across Canada, <a href="https://dx.doi.org/10.1139/facets-2021-0122">developed five actionable solutions</a> for Canada’s marine conservation under climate change, with a modernized Oceans Act at its core. </p>
<h2>Species are on the move</h2>
<p>The shift in the feeding grounds of these whales seems to be closely <a href="https://doi.org/10.5670/oceanog.2021.308">linked to warmer ocean temperatures</a>, brought about by ongoing and intensifying climate change. </p>
<figure class="align-center ">
<img alt="A whale and a whale calf swim on the surface of the water." src="https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/457008/original/file-20220407-24242-d8eqbt.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">Increasing ocean surface temperatures and a corresponding decline of small crustaceans, like zooplankton and krill, has forced the North Atlantic right whale to search for new feeding grounds.</span>
<span class="attribution"><span class="source">(FWC Fish and Wildlife Research Institute/flickr)</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>With greenhouse gas emissions on a rise, our oceans <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content">absorb more heat, ultimately leading to higher surface temperatures</a> in the key habitats of many iconic marine species, such as the North Atlantic right whale. The amount of crustaceans available for North Atlantic right whales to feed on <a href="https://doi.org/10.1038/s41598-017-06524-1">seems to decline</a> with higher temperatures. </p>
<p><a href="https://doi.org/10.1126/science.aai9214">Species are on the move</a> faster than ever today, as they explore new ecosystems and create new ecological communities to stay within their preferred environment.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/species-on-the-move-4-ways-conservation-can-adapt-in-an-era-of-climate-change-179254">Species on the move: 4 ways conservation can adapt in an era of climate change</a>
</strong>
</em>
</p>
<hr>
<p>While Canada has a <a href="https://www.dfo-mpo.gc.ca/oceans/publications/mpanf-cnzpm/index-eng.html">marine conservation framework</a> in place to protect marine biodiversity in its waters, this protection is firmly static in space and not ideally suited for our highly dynamic oceans in times of a climate emergency. </p>
<p>The unpredictable nature of our changing oceans poses a problem for how we currently approach marine conservation under the <a href="https://laws-lois.justice.gc.ca/eng/acts/o-2.4/FullText.html">Oceans Act</a> and other conservation frameworks in Canada such as the <a href="https://laws.justice.gc.ca/eng/acts/S-15.3/">Species at Risk Act</a> and <a href="https://laws-lois.justice.gc.ca/eng/acts/f-14/">Fisheries Act</a>. </p>
<h2>Canada’s marine protected areas</h2>
<p>Today, <a href="https://www.dfo-mpo.gc.ca/oceans/mpa-zpm/index-eng.html">14 marine protected areas (MPAs)</a> cover about six per cent of Canada’s marine and coastal areas under the Oceans Act. These MPAs were established to protect either unique species or their habitats. </p>
<p>Some iconic MPAs include the <a href="https://www.dfo-mpo.gc.ca/oceans/mpa-zpm/gully/index-eng.html">Gully MPA</a> on the edge of the Atlantic Scotian Shelf, the <a href="https://www.dfo-mpo.gc.ca/oceans/mpa-zpm/bowie-eng.html">Sgaan Kinghlas-Bowie Seamount MPA</a> west of Haida Gwaii in the Pacific Ocean and the recently established <a href="https://www.dfo-mpo.gc.ca/oceans/mpa-zpm/tuvaijuittuq/index-eng.html">Tuvaijuittuq MPA</a> in the High Arctic. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/fnz-JszBVNM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Marine Protected Areas protect and restore endangered species, conserve biodiversity, enhance the resilience of unique coastal ecosystems and also enhance fisheries.</span></figcaption>
</figure>
<p>Much like the North Atlantic right whales moving away from their historical aggregation sites, changes are beginning to appear in other Canadian waters and their protected areas. </p>
<p><a href="https://www.cbc.ca/news/canada/nova-scotia/tropical-fish-nova-scotia-1.5248688">New species like some tropical fishes are appearing more frequently</a>, others are <a href="https://doi.org/10.1525/elementa.2020.00076">moving further north or into deeper waters,</a> leaving the waters where they were protected.</p>
<h2>Modernizing the Oceans Act</h2>
<p>Now is the time to acknowledge and address the rapid shifts in Canada’s oceans. To meet this challenge, Canada’s marine conservation toolbox — starting with the Oceans Act — needs an overhaul. </p>
<p>The Oceans Act dates back to 1996 and while it has been amended several times since, it does not mention climate change once. </p>
<p><a href="https://dx.doi.org/10.1139/facets-2021-0122">Our recent research</a> suggests amending the Oceans Act to explicitly consider climate change impacts on marine ecosystems and species in ocean management and consider applicable actions. If we want to move forward with meaningful marine conservation in Canada, our central tool for marine conservation needs to address the urgent issue of global climate change.</p>
<p>Not only does the Oceans Act fail to address the impacts of ongoing climate change, <a href="https://doi.org/10.3389/fmars.2021.711085">research</a> also found Canada is lagging far behind other comparable nations in terms of integrating climate change in the management of its marine protected areas.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"761245741901811712"}"></div></p>
<p>Adapting marine conservation to climate change boils down to changing legislation and embracing new technologies such as sensor-equipped robotic submarines and airborne drones. New technologies can bolster the existing marine conservation toolbox to address the impacts of climate change. </p>
<p>This was shown, for example, in the recent development of <a href="https://doi.org/10.1126/science.abb5115">dynamic protection measures</a> that used these technologies to track and observe North Atlantic right whales in Atlantic Canadian waters in real time. </p>
<p>We suggest combining these dynamic protection measures with the existing static MPA network in Canada’s oceans to allow for climate change-induced species shifts.</p>
<h2>Taking leadership in ocean conservation</h2>
<p>Canada is emerging as a global leader in ocean conservation, committed to protecting <a href="https://www.cbc.ca/radio/quirks/jan-16-snake-lasso-climbing-seeing-gravitational-waves-with-pulsars-soil-compaction-and-more-1.5873142/canada-committed-to-protecting-30-of-our-territory-by-2030-which-30-should-it-be-1.5873148">30 per cent of Canada’s ocean by 2030</a>. </p>
<p>It is also committed to modernizing the Oceans Act “to explicitly consider climate change impacts on marine ecosystems […],” as stated in the 2021 <a href="https://pm.gc.ca/en/mandate-letters/2021/12/16/minister-fisheries-oceans-and-canadian-coast-guard-mandate-letter">mandate letter</a> for the minister of fisheries, oceans and the Canadian Coast Guard. </p>
<p>While these national and international commitments are a sign of progress towards climate-adaptive marine conservation, Canada needs to step up to the plate to safeguard its oceans from a changing climate. It needs to overhaul its marine conservation toolbox.</p><img src="https://counter.theconversation.com/content/177895/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrea Bryndum-Buchholz receives funding from MEOPAR Postdoctoral Fellowship Award and the Ocean Frontier Institute Module G funded by the Canada First Research Excellence Fund. </span></em></p><p class="fine-print"><em><span>Kristina Boerder receives funding from Global Fishing Watch</span></em></p>It is time to acknowledge and address the rapid shifts in Canada’s oceans. To meet this challenge, Canada’s marine conservation toolbox — starting with the Oceans Act — needs an overhaul.Andrea Bryndum-Buchholz, Postdoctoral Researcher in Marine Ecology and Climate-Impact Sciences, Memorial University of NewfoundlandKristina Boerder, Postdoctoral fellow in marine conservation, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1773572022-02-17T05:49:21Z2022-02-17T05:49:21ZSydney shark attack triggers calls for a cull – but let’s take a deep breath and look at the evidence<p>The fatal <a href="https://www.theguardian.com/australia-news/2022/feb/17/fatal-shark-attack-sydney-beaches-closed-as-lifeguards-patrol-for-further-sightings">shark attack</a> off Sydney on Wednesday left the city shocked, and triggered questions from a horrified public. Why would a shark just grab a man from the water? And will it strike again?</p>
<p>The incident – Sydney’s first fatal shark attack since 1963 – has prompted debate on what to do next. Some people even <a href="https://twitter.com/Robert44183163/status/1493885115801686018">took to social media</a> to call for <a href="https://www.dailymail.co.uk/news/article-10520615/Shark-attack-Sydney-Little-Bay-sparks-calls-shark-cull.html">sharks to be culled</a>.</p>
<p>This is a common community response following unprovoked shark attacks. But killing sharks is highly controversial. And as <a href="https://research.bond.edu.au/en/publications/a-comparison-of-alternative-systems-to-catch-and-kill-for-mitigat">my research</a> has shown, there are many non-lethal alternatives to protect beachgoers from sharks. </p>
<p>As authorities grapple with the best way to respond to this tragedy, it’s worth remembering all shark mitigation measures come with both merits and drawbacks – and none is a silver bullet.</p>
<figure class="align-center ">
<img alt="people walk towards beach" src="https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446948/original/file-20220217-13-1cukycs.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 incident was Sydney’s first fatal shark attack since 1963.</span>
<span class="attribution"><span class="source">Bianca De Marchii/AAP</span></span>
</figcaption>
</figure>
<h2>Killing sharks is problematic</h2>
<p>It’s unlikely authorities would ever be able to hunt down the individual shark involved in Wednesday’s fatality. As Macquarie University marine scientist Vanessa Pirotta has <a href="https://www.theguardian.com/australia-news/2022/feb/17/fatal-shark-attack-sydney-beaches-closed-as-lifeguards-patrol-for-further-sightings">noted</a>, sharks travel large distances and the animal is likely to be long gone. </p>
<p>Other times, members of the community call for an area-wide shark cull – and in rare cases a government will oblige.</p>
<p>In Western Australia in 2013, for example, the then Liberal government <a href="https://www.watoday.com.au/national/western-australia/how-was-shark-kill-zones-will-work-20131224-2zvmn.html">announced</a> shark “kill zones” near beaches following a string of attacks. But the measure was scrapped after fierce opposition from the public and environment officials.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-were-opposing-western-australias-shark-cull-scientists-28653">Why we're opposing Western Australia's shark cull: scientists</a>
</strong>
</em>
</p>
<hr>
<p>Any increased effort to kill sharks is likely to face public and political opposition, for several reasons.</p>
<p>First, sharks pose a low risk to humans. It’s true that globally, the frequency of unprovoked shark bites has <a href="https://doi.org/10.1080/08920753.2014.942046">increased</a>, due to factors such as more water users and changes in shark distribution and behaviour.</p>
<p>But the probability of an unprovoked shark bite remains low.</p>
<p>Second, public perception towards sharks is changing. Many people now realise the intrinsic value of sharks and their important role in marine ecosystems.</p>
<p>Given all this, we must keep pursuing non-lethal methods to protect swimmers and surfers from sharks while avoiding environmental damage.</p>
<p>Let’s look at such approaches in more detail.</p>
<figure class="align-center ">
<img alt="sharks swim on reef" src="https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446949/original/file-20220217-25-1i2izfk.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">Many people recognise sharks’ vital role in marine ecosystems.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Aerial surveys</h2>
<p>Aerial surveys involve detecting sharks via a plane, helicopter or unmanned drone, or by people on land.</p>
<p>Their effectiveness can vary depending on how clear, calm or deep the water is, and on wind strength and shark behaviour.</p>
<p>An aircraft with human observers on board can survey a lot of coastline. But an aircraft can spend less than a minute on each beach, limiting the opportunity to locate a shark. </p>
<p>And <a href="https://doi.org/10.1371/journal.pone.0083456">research</a> has shown even in reasonably clear water, overall rates of detection from planes and helicopters is low.</p>
<p>Drones cost less to operate than manned aircraft and are better for surveying a single location. However, battery constraints mean commercially available models can only stay airborne for a limited time.</p>
<p>In future, drones could be tethered to helium balloons or kites to allow for longer-term surveillance. But such technology is still at an early stage.</p>
<p>Surf patrol towers can help lifeguards detect sharks. But they must offer a vantage point <a href="https://doi.org/%2010.1186/s40462-018-0125-5">more than 40 metres</a> above sea level to be suitable for the task - a height well above that normally afforded by existing towers.</p>
<figure class="align-center ">
<img alt="lifeguard tower and busy beach" src="https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446954/original/file-20220217-34819-9g4l5a.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">Lifeguard towers are not always high enough to enable shark spotting.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Nets and drumlines</h2>
<p>Sharks can be detected by capturing then releasing them. These methods include deploying either mesh nets or “drumlines” – baited hooks that lure sharks.</p>
<p>Shark nets operate at more than 50 NSW beaches in the warmer months. The program releases all live sharks caught in nets, but <a href="https://www.sharksmart.nsw.gov.au/__data/assets/pdf_file/0011/856163/Shark-Meshing-2016-2017-annual-report.pdf">more than 80%</a> of large “target” sharks caught in the nets die.</p>
<p>Traditional drumlines, used extensively in Queensland, also historically kill a <a href="https://doi.org/10.2989/%201814232X.2011.572335">significant proportion</a> of sharks. </p>
<p>New <a href="https://www.sharksmart.nsw.gov.au/technology-trials-and-research/smart-drumlines">“SMART” drumlines</a> are designed to kill fewer captured animals. The device issues an alert when an animal is caught, and a contractor unhooks and relocates it.</p>
<p>Over three years of SMART drumline trials in NSW, high levels of live shark releases were reported. But the method requires extra labour expense to ensure rapid response to a capture.</p>
<figure class="align-center ">
<img alt="shark hangs on hook" src="https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446958/original/file-20220217-23-1und25o.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">Drum lines can kill sharks.</span>
<span class="attribution"><span class="source">Humane Society International</span></span>
</figcaption>
</figure>
<h2>Area-based deterrents</h2>
<p>Electrical shark deterrents have been investigated over many years. Research shows substantial promise, and Australia is making progress in <a href="https://ocean-guardian.com/">commercialising</a> the technology. </p>
<p>Scientists have investigated using acoustic deterrents such as orca calls and novel sounds to deter sharks. But such methods do not work on all shark species, and the impacts on other animals needs to be considered.</p>
<p>Physical barriers to exclude sharks from a particular area is a longstanding approach to protect bathers. Permanent swimming enclosures have worked in areas protected from exposed ocean conditions, such as Sydney Harbour. </p>
<p>But on ocean beaches, physical barriers must be designed to withstand constant wave energy, including extreme conditions. Previous attempted trials on NSW surf beaches <a href="https://www.abc.net.au/news/2016-09-14/second-shark-barrier-trial-scrapped-nsw/7843566">failed</a> as the gear either could not be installed, or was destroyed by the surf. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fatal-shark-attacks-are-at-a-record-high-deterrent-devices-can-help-but-some-may-be-nothing-but-snake-oil-150845">Fatal shark attacks are at a record high. 'Deterrent' devices can help, but some may be nothing but snake oil</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="shark net in water" src="https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=479&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=479&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=479&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=602&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=602&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446959/original/file-20220217-25-1th8rms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=602&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shark nets can tear in rough ocean conditions.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>No quick fix</h2>
<p>Wednesday’s fatal shark attack has understandably shaken the community and prompted debate. In all this, of course, we must remember that a human life has been lost.</p>
<p>Right now, talk of preventing future attacks will be of little comfort to the victim’s family and friends, eyewitnesses and first responders.</p>
<p>Looking further ahead, no system will ever deter or detect 100% of sharks. But risks can be reduced with well-considered approaches, suited to local conditions. </p>
<p>More research is needed into non-lethal strategies. The cost of various approaches is also an important consideration.</p>
<p>And no matter what system is used to protect beachgoers, it should be accompanied by efforts to educate the public about shark safety. </p>
<p>Tips include avoiding swimming or surfing in low light levels, avoiding beaches near estuaries after heavy rain and flooding, and avoiding places where stranded marine mammals are present – as the sites may attract sharks.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/shark-bites-are-rare-here-are-8-things-to-avoid-to-make-them-even-rarer-173746">Shark bites are rare. Here are 8 things to avoid to make them even rarer</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/177357/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daryl McPhee has previously received funding from the NSW, Queensland and WA Governments to investigate unprovoked shark bite and mitigation responses. This article was based on the publication "A comparison of alternative systems to catch and kill for mitigating unprovoked shark bite on bathers or surfers at ocean beaches" in the journal Ocean and Coastal Management which was partly funded by the NSW DPI. Dr McPhee is not currently in receipt of any research or other funding associated with the sharks and shark-human interactions. </span></em></p>As authorities grapple with the best way to respond to the tragedy, it’s worth remembering all shark mitigation measures come with both merits and drawbacks – and none is a silver bullet.Daryl McPhee, Associate Professor of Environmental Science, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1770912022-02-15T12:25:27Z2022-02-15T12:25:27ZCod ‘supergenes’ reveal how they are evolving in response to overfishing<figure><img src="https://images.theconversation.com/files/446276/original/file-20220214-17-1gcop80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Travel Faery / shutterstock</span></span></figcaption></figure><p>Cod “supergenes” have shed light on how they respond to overfishing, and these supergenes could make them more resilient to other environmental changes. That’s according to a <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.2114904119">new study</a> published by scientists in Norway. This could be good news, in that cod have genetic architecture in place that will permit them to respond to climate change – but for now this is rather speculative.</p>
<p>For those of us who study how fish species evolve under strong selective pressure from commercial fishing, cod has been a poster species. For instance scientists have previously found that cod in the north west Atlantic showed signs of reproducing at <a href="https://pubmed.ncbi.nlm.nih.gov/15118724/">a smaller size or younger age</a> before numbers collapsed.</p>
<p>The latest study examined the current and historical genome (the complete set of genetic instructions contained in an organism’s DNA) of cod. The scientists were particularly interested in areas of highly-conserved “supergenes” and what they can tell us about these ecologically critical but heavily exploited marine predators.</p>
<p>Supergenes are not extra individual genes as such. Rather they are combinations of genetic material that are more conserved through the generations. Often they are strongly coupled or linked and are responsible for a set of traits in an organism that are very important such as linking growth rates with reproduction capacity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Unhappy looking fish" src="https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446499/original/file-20220215-15-7akxq2.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">Freshly caught cod from the North Sea.</span>
<span class="attribution"><span class="source">Ingrid Maasik / shutterstock</span></span>
</figcaption>
</figure>
<p>The authors found three supergenes conserved in the cod off Norwegian shores. And the three supergenes were found in different relative abundance in two distinct cod populations: inshore and offshore. This reinforces what we know about cod in the north east Atlantic and is a good thing, since if the cod were all one breeding population they would be more vulnerable to overexploitation.</p>
<p>An interesting consequence of this research is that the scientists can combine their genomics approaches with knowledge from old stories and pictures, and records of fish bones and fishing equipment found at archeological sites, in order to reconstruct the likely population sizes of cod through history. Recent studies on several fish species have shown the true baseline of their abundance in seas around Europe is <a href="https://www.nature.com/articles/srep29269">likely underappreciated</a>. Indeed, this new analysis suggests the overexploitation of cod reduced their abundance many hundreds of years before modern commercial fishing began, and the signature of overexploitations is etched in their genome.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Chart showing abundance of cod over time, illustrated with typical fishing gear of every era." src="https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=682&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=682&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=682&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=857&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=857&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446496/original/file-20220215-21-bici20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=857&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cod in the north east Atlantic were in decline even before modern fishing.</span>
<span class="attribution"><a class="source" href="https://www.pnas.org/content/119/8/e2114904119/tab-figures-data">Sodeland et al (2022) / PNAS</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>How human predators change their prey</h2>
<p>Across lots of different species, it is now well recognised that populations are constantly changing, and this includes evolved changes to their body size, shape or traits like growth rate being observed in just a few generations with significant consequences for how population numbers fluctuate.</p>
<p>Scientists recently updated a <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mec.16299">large data set</a> that now compiles more than 7,000 examples of contemporary changes to biological traits in wild populations. The researchers examined whether observed trait changes such as a shift in average body size were short term and reversible, or whether they were more permanent evolved responses to some change in the local environment such as increasing temperature or an introduced predator.</p>
<p>Their data clearly showed that the largest and fastest rates of trait change were associated with predation – for example when a predator picks off the slowest, smallest, largest or least camouflaged individuals in a wild population – leading to directional change to being smaller, larger, or faster. These rates of change were especially fast when that predator was human.</p>
<p>Theories of human caused <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.2164">harvest-induced evolution</a> are now well established, and there are many good examples where selective harvest of fish and game species has caused long term change, for example by influencing behaviour, body shape or size and growth rates to sexual maturity. I have carried out <a href="https://onlinelibrary.wiley.com/doi/10.1111/ele.12107">laboratory based research</a> which has demonstrated both the probability that harvest-induced evolution can occur, but also the likely impact such permanent genetic change can have on things like population size or resulting yields.</p>
<p>This field of study is not without controversy, but it is now generally accepted that we should take evolutionary selection pressure into account when we utilise wild animals and plants for resources. As new scientific approaches and opportunities to examine the genome of wild animals emerge, we may find more supergenes and the stories they can tell us of how organisms respond to the world they live in.</p><img src="https://counter.theconversation.com/content/177091/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Cameron has received funding from UK based Natural Environment Research Council to work on Harvest Induced Evolution.</span></em></p>Certain combinations of genetic material are being conserved through the generations.Tom Cameron, Senior Lecturer in Ecology, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1704802021-11-05T16:06:57Z2021-11-05T16:06:57ZCOP26: Scotland’s coral reefs are on the line at Glasgow climate change summit<figure><img src="https://images.theconversation.com/files/429920/original/file-20211103-18-9l73tr.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3504%2C2334&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cold-water coral reefs occur at greater depths than their tropical equivalents.</span> <span class="attribution"><span class="source">Sebastian Hennige</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The demise of tropical coral reefs has come to symbolise the threat of climate change to the natural world. Teeming with life and bursting with colour, these habitats may feel a world away from the cold, windswept streets of Glasgow, where world leaders are gathering for the annual UN climate summit. </p>
<p>But not far offshore lie vast reefs formed by species of cold-water coral and calcified seaweed. This latter kind are commonly known as maerl beds and are created by a chalky pink seaweed filled with calcium carbonate – the same compound which makes up coral skeletons.</p>
<p>Cold-water coral reefs ring the western and northern sea shelf of the UK, typically at depths of 50 metres or more. The UK is a European stronghold for maerl beds too, especially in Scotland, where they are found all along the west coast and around the islands.</p>
<p>Just like their tropical equivalents, cold-water coral reefs and maerl beds are some of the most biodiverse ecosystems on the planet and provide a home to economically important species like pollack, scallops and <a href="https://www.sciencedirect.com/science/article/pii/S0006320713000682">catsharks</a>. Sadly, despite their economic and ecological importance, climate change could erase Britain’s reefs by the end of the century.</p>
<h2>Climate change poses multiple threats</h2>
<p>Rising concentrations of carbon dioxide (CO₂) in the atmosphere are raising the planet’s temperature. Since the 1970s, the ocean has absorbed 93% of that excess heat. Climate models project that ocean temperatures may increase by <a href="https://www.ipcc.ch/assessment-report/ar6/">more than 4°C by 2100</a> as a result. </p>
<p>Each species of maerl has evolved to thrive in a very narrow temperature range. Many areas of the UK’s coastal seas are expected to become <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.575825/full">too warm</a> for native species even by 2050.</p>
<p>Scientists believe that cold-water corals, on the other hand, can cope with relatively large changes in temperature. But they need to <a href="https://www.frontiersin.org/articles/10.3389/fphys.2019.01636/full">raise their calorie intake</a> to do so. Put simply, to resist the stress of climate change and continue growing at a healthy rate, cold-water corals will need more food. Corals are passive feeders, using their tiny tentacles to snare the small animals, microscopic algae and detritus that comes close. They will need more food to weather climate change, but they have no control over this.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Seafloor habitat with pink clumps of maerl, rocks and seaweed." src="https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/429350/original/file-20211029-23-1j2x5b2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A maerl bed off the west coast of Scotland.</span>
<span class="attribution"><span class="source">Nick Kamenos</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>As ice shelves melt, the warming ocean is inundated with fresh water. This is expected to change patterns of ocean circulation. The Gulf Stream – a warm ocean current which originates in the Gulf of Mexico – is already slower now than it has been for at least <a href="https://www.nature.com/articles/s41561-021-00699-z">the past 1,000 years</a>. This current influences the UK’s weather and climate, so any changes will have a big effect on the country’s coastal seas. </p>
<p>Unlike tropical corals, which harvest energy from the sun, cold-water corals get all their sustenance from the plankton and organic detritus they can catch. Currents slowing down or changing direction could slash how much food the corals have access to. Maerl beds are found only where fast currents prevent sediment from smothering it so that the maerl can make enough food from photosynthesis. Changes in water movement are expected to be a major factor in the loss of Scotland’s maerl beds over the <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.575825/full">coming decades</a>.</p>
<h2>A future for reefs</h2>
<p>Greenhouse gas emissions don’t just heat the atmosphere. When CO₂ dissolves in seawater it makes it more acidic. The ocean is becoming ever more corrosive to <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.12351">plants</a> and animals with calcium carbonate skeletons. Cold-water corals are incredibly sensitive to this, in part because they tend to live in deeper waters where the pH is already lower than at the surface. </p>
<p>By 2100, <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/1540-9295%282006%29004%5B0141%3AWHCISC%5D2.0.CO%3B2?casa_token=MWb2X_snyJ4AAAAA%3AT72YQWyrmziJKfrue15So94dGY34njxu7NVZVuRzp_N2oKJNOOK9f_ddAalg8iT9CKmRMMF-StAuo3I">more than 70%</a> of cold-water coral habitats worldwide are expected to be in waters that are corrosive to calcium carbonate. These conditions result in weaker skeletons, akin to the loss in bone density which happens in people suffering with osteoporosis. Cold water coral reefs and maerl beds face a daily battering from animals, storms and dredging – weaker skeletons will make them more prone to damage, and may cause reefs to <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.00668/full">crumble</a>.</p>
<p>Climate change spawns multiple sources of stress simultaneously for marine organisms. The combined effects mean both cold-water coral reefs and maerl beds will struggle to build skeletons and balance their energy budgets. Both maerl and cold water corals grow very slowly (0.2mm a year for maerl) and can live for centuries. Some reefs are thousands of years old. This means their ability to recover is low compared to faster growing habitats such as kelp forests. Losing cold-water corals and maerl, or even a <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2016.1159">change in reef structures</a>, will mean the plants and animals that live in them will lose their home.</p>
<p>From their watery vantage point, Scottish corals and maerl would no doubt hope for a positive outcome in Glasgow. If greenhouse gas emissions continue unabated, cold-water coral reef habitat in the North Atlantic is likely to shrink by <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.14996">at least 79%</a> by 2100. Meanwhile, <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.575825/full">up to 84%</a> of Scottish maerl beds could disappear by the end of the century. But, if the global community can reduce emissions enough to limit warming to less than 2°C by 2100 (the maximum target in climate negotiations), the decline in Scottish maerl beds could be reduced to 38%. </p>
<p>Cold-water coral reefs and maerl beds are recognised as internationally-important habitats for biodiversity, and more recently for their potential to <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15021">lock away lots of carbon</a>. To avoid catastrophic losses in these habitats, the world must significantly curb greenhouse gas emissions and limit the effects of climate change – research suggests this will allow them to <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12351">keep building their skeletons</a>. </p>
<hr>
<figure class="align-right ">
<img alt="COP26: the world's biggest climate talks" src="https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424739/original/file-20211005-17-cgrf2z.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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<p><strong>This story is part of The Conversation’s coverage on COP26, the Glasgow climate conference, by experts from around the world.</strong>
<br><em>Amid a rising tide of climate news and stories, The Conversation is here to clear the air and make sure you get information you can trust. <a href="https://page.theconversation.com/cop26-glasgow-2021-climate-change-summit/"><strong>More.</strong></a></em> </p>
<hr><img src="https://counter.theconversation.com/content/170480/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heidi Burdett receives funding from the Natural Environment Research Council, UK Research and Innovation and the Leverhulme Trust.</span></em></p><p class="fine-print"><em><span>Cornelia Simon-Nutbrown receives funding from a NERC iCASE PhD studentship. </span></em></p>Cold-water corals live in the Atlantic’s frigid depths – and the UK is a stronghold for them.Heidi Burdett, Associate Professor, Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt UniversityCornelia Simon-Nutbrown, PhD Candidate in Marine Conservation, Heriot-Watt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1688512021-10-05T19:07:36Z2021-10-05T19:07:36ZHow fussy eating and changing environments led to the diversity of sharks today (and spelled the end for megalodon)<figure><img src="https://images.theconversation.com/files/424002/original/file-20210930-16-qezo3t.png?ixlib=rb-1.1.0&rect=47%2C5%2C3950%2C2469&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Artwork by José Vitor Silva</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Before humans and early primates, before dinosaurs, and even before trees, there were sharks. Sharks have been around for more than 400 million years (although how long exactly <a href="https://www.nhm.ac.uk/discover/shark-evolution-a-450-million-year-timeline.html">remains contested</a>). They have survived five <a href="https://cosmosmagazine.com/history/the-big-five-mass-extinctions/">major mass extinctions</a>.</p>
<p>But the sharks of long ago are not like the ones we see today. In fact, we still understand quite little about their long-term evolution. Our research, <a href="https://doi.org/10.1016/j.cub.2021.09.028">published today</a> in the journal Current Biology, demonstrates how shark evolution over the past 83 million years has been driven by diet preference and climate change — leading to the diversity we see today. </p>
<p>As it turns out, being picky about your prey is a risky game for sharks to play.</p>
<h2>When the scales tipped</h2>
<p>One of the more peculiar patterns in biology is for very closely related orders of living animals to have greatly different numbers of species. A notable example is the difference in species number between mackerel sharks (the Lamniformes order) and ground sharks (the Carcharhiniformes order). </p>
<p>Both orders share nearly 170 million years of evolutionary history, and both have species found the world over. However, there are only 15 species of Lamniformes known today (including the great white shark), compared to more than 290 species of Carcharhiniformes (including hammerheads, tiger sharks and many species found on coral reefs). </p>
<p>But why do some orders of shark thrive, while others dwindle? To find out, we turned to the fossil record.</p>
<p>The fossil record reveals shark species in prehistoric times followed a very different pattern to species alive today. Before the “age of dinosaurs” ended some 66 million years ago, at the end of the Cretaceous Period, Lamniformes were <em>more</em> diverse than Carcharhiniformes.</p>
<p>To investigate this shift, we looked at changes in the shapes of shark teeth over the past 83 million years.</p>
<h2>Why teeth?</h2>
<p>Unlike their soft cartilaginous skeleton, shark teeth are made up of a substance called “enameloid”, making them very hard. Sharks also continuously grow new teeth, which means their teeth provide an almost continuous fossil record.</p>
<p>Luckily, the shapes of shark teeth also provide rich information on their diets. For instance, a fish-eating shark is likely to have pointy, narrow teeth — often with multiple cusps to increase its chances of catching slippery prey (see the image of the mako shark below, a predominately bony-fish specialist). </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=315&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=315&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=315&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=396&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=396&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424418/original/file-20211004-25-1c22enb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=396&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The shortfin mako, <em>Isurus oxyrinchus</em>, belongs to the Lamniformes order. (Scale bar = 100mm).</span>
<span class="attribution"><span class="source">Mohamad Bazzi</span></span>
</figcaption>
</figure>
<p>By comparison, a shark that specialises in hunting seals is more likely to have broad teeth, which may be serrated to help with cutting. It is precisely this variation in tooth shape which we focused on in our latest study.</p>
<p>By examining more than 3,000 teeth, we found a clear link between changes in tooth shape over time and changes in the environment that took place during and after the end-Cretaceous mass extinction — the same event that wiped-out non-bird dinosaurs about 66 million years ago.</p>
<h2>Plenty of fish, yet sharks can be choosy</h2>
<p>During the Cretaceous, when Laminformes were more abundant, many shark species lived in inland seas that were common at the time. One example was the Western Interior Seaway, which divided North America into east and west “subcontinents”.</p>
<p>However, towards the end of the Cretaceous, these inland seas started disappearing. Sea levels lowered and exposed entire chunks of land. Inland seas are rare today (the Caspian Sea is one example, but it too is receding).</p>
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Read more:
<a href="https://theconversation.com/the-caspian-sea-is-set-to-fall-by-9-metres-or-more-this-century-an-ecocide-is-imminent-152229">The Caspian Sea is set to fall by 9 metres or more this century – an ecocide is imminent</a>
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<p>The reduction in these marine ecosystems led to a significant loss of wildlife, including marine reptiles and cephalopod ammonites (relatives of squid and octopus) upon which many Cretaceous Lamniformes preyed. </p>
<p>As a result, many Lamniformes suffered <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(18)30763-2">extinction</a>. On the other hand, Lamniformes with more generalised diets survived the extinction event — as did Carcharhiniformes, which also tend to have more generalised diets.</p>
<h2>Why the meg went missing</h2>
<p>A similar event may have occurred just a few million years ago to one of the most awe-inspiring lamniform sharks ever known: the meg (<em>Otodus megalodon</em>). The meg was the largest predatory shark species to have existed. </p>
<p>Megalodon was truly an imposing predator that lived during the Miocene and early Pliocene, roughly 4—23 million years ago. Based on its tooth shape, it likely specialised in eating whales, which were very diverse at that time. </p>
<p>Our results show the period in which it lived was also a turning point for Lamniformes, with record-low tooth disparity (a loss in the amount of shape variation). </p>
<p>Although it’s still difficult to know why exactly the meg went extinct, it’s likely its specialised diet, which might have included the giant sperm whale <a href="https://www.nationalgeographic.com/science/article/behold-leviathan-the-sperm-whale-that-killed-other-whales"><em>Leviathan melvillei</em></a>, put it at a disadvantage as cooling climates during the Miocene and Pliocene led to changes in its preferred diet. </p>
<p>To generalise, it seems specialised diets, such as that of the megalodon and some Cretaceous Lamniformes, may have put these species at a greater risk of extinction.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/making-a-megalodon-the-evolving-science-behind-estimating-the-size-of-the-largest-ever-killer-shark-155475">Making a megalodon: the evolving science behind estimating the size of the largest ever killer shark</a>
</strong>
</em>
</p>
<hr>
<h2>Today’s species</h2>
<p>So what does this mean for modern sharks?</p>
<p>By studying the stomach contents of modern Lamniformes, we found most species tend to feed on specific food groups. The thresher and mako sharks feed primarily on bony fish. The basking shark exclusively eats plankton, while adult great white sharks feed mainly on mammals. </p>
<p>Since Lamniformes were much more diverse in the past, our research indicates the low diversity of Lamniformes living today is likely the result of repeated extinction events.</p>
<p>By comparison, modern and past Carcharhiniformes are and were more flexible in their diets. They also benefited directly from the expansion of coral reefs over the past 50 million years. </p>
<p>Thanks to important biological insights offered by the fossil record, we now have evidence dietary specialisation and adaptability to environmental changes likely drove shark evolution over the past 83 million years — leading to the imbalance in Lamniformes and Carcharhiniformes species numbers today.</p>
<p>But what does the future hold? Although it’s hard to say for sure, the news isn’t great for Lamniformes. Of the 15 species remaining, five are classified as “endangered” or “critically endangered” by the <a href="https://www.iucnredlist.org/search?taxonomies=100308&searchType=species">International Union for Conservation of Nature and Natural Resources</a>. Another five are considered “vulnerable”. </p>
<p>Lamniformes are also mostly oceanic species with specialised diets, and are therefore particularly vulnerable to chronic <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(21)01198-2">overfishing</a> and <a href="https://www.nature.com/articles/s41586-020-03173-9">habitat destruction</a>.<br>
And since our results indicate diet and prey availability underpinned much of the diversity among modern sharks, we think it will probably decide their survival in the future, too.</p><img src="https://counter.theconversation.com/content/168851/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mohamad Bazzi receives funding from Forschungskredit (K-74604-01-01).</span></em></p><p class="fine-print"><em><span>Nicolas Campione receives funding from the Australian Research Council Discovery Early Career Research Award (DE190101423). </span></em></p>Sharks have been around for more than 400 million years — but not all sharks are equally resilient to changes around them. Why do some groups thrive, while others dwindle?Mohamad Bazzi, Postdoctoral research fellow, University of ZurichNicolas Campione, Senior lecturer, University of New EnglandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1630582021-08-02T12:38:30Z2021-08-02T12:38:30ZWhat’s driving the huge blooms of brown seaweed piling up on Florida and Caribbean beaches?<figure><img src="https://images.theconversation.com/files/412995/original/file-20210725-13-iyuaeq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mats of Sargassum seaweed off the coast of St. Martin in April 2018.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=71649893">ELY Michel CC BY-SA 4.0, </a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Here’s a handy geography question for your next trivia match: What is the world’s only sea that doesn’t have a land border?</p>
<p>The answer is the <a href="https://oceanservice.noaa.gov/facts/sargassosea.html">Sargasso Sea</a> – a 2-million-square-nautical-mile haven of biodiversity that lies east of Bermuda in the Atlantic Ocean. Rather than beaches, it’s bounded by <a href="https://oceanservice.noaa.gov/facts/gyre.html">rotating ocean currents</a> that form the North Atlantic Subtropical Gyre.</p>
<p>The Sargasso is named for <a href="https://oceanexplorer.noaa.gov/facts/sargassum.html">sargassum</a>, a free-floating brown seaweed that grows in its calm, clear waters. In the open ocean this seaweed serves as nursery grounds and a haven for sea life. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412944/original/file-20210723-13-qcazqk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&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 Sargasso Sea.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/101077452@N05/21018040290/in/photolist-y2hX81-2jfTTMa-3pCkM-8qYWcq-8qYWYN-RTCj5t-5NKpKx-vnpXgv-242GLcX-5LdnCW-5Ldnam-wgyfkq-oUvy98-oUtHm7-sqKACN-ByXNZT-2kcP2gz-LdV2bL-28mMvQn-yhZNKQ-5mqWPW-XACWvy-hQNCY5-hQMUXx-hQNSDR-USu7zz-Mx6NKR-8dxQRN-fQhCrF-hQNvfb-285yLHo-hQN4ta-RcDvzW-hQNAf9-hQN11i-hQN2ng-fgHUh9-G7A6p9-TyjYHG-tETSDV-hQNLzM-hQNx25-EHWEAr-pSssdz-omDkoY-omDJc2-evUXXN-nz5dor-fg7Nu9-ew7bNk">rjsinenomine/Flicker</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>But over the past decade, a new “Great Atlantic Sargassum Belt” has inundated <a href="https://www.nola.com/news/environment/article_d23f12b6-8f21-11eb-9a26-d7b9068fcc1b.html">Caribbean</a>, <a href="https://www.theguardian.com/environment/2020/jun/30/how-do-you-deal-with-9m-tonnes-of-suffocating-seaweed-aoe">Gulf of Mexico</a> and <a href="https://www.tcpalm.com/story/news/local/indian-river-lagoon/2021/05/28/sargassum-seaweed-florida-beaches-10-things-know-algae-sargasso-sea-gulfweed-sea-holly/7428135002/">Florida</a> coastlines, wreaking environmental and economic havoc. It’s <a href="https://www.costar.com/article/1897972322">driving away tourists</a>, devastating local fishing industries and requires costly cleanup. </p>
<p>In my work as a <a href="https://scholar.google.com/citations?user=0QZKY20AAAAJ&hl=en">coastal scientist</a>, I’ve watched these invasions become the new normal, choking beaches and turning clear blue waters golden brown. Along with other researchers, I’m trying to understand why sargassum has proliferated into this new sprawling bloom, how to deal with such massive amounts of it, and how affected countries can predict the severity of the next influx. </p>
<h2>A mysterious ‘golden floating rainforest’</h2>
<p>For centuries people have viewed the Sargasso Sea with <a href="https://www.thebermudian.com/home-a-garden/nature/mysteries-of-the-sargasso-sea/">superstition and fear</a>. <a href="http://www.sargassoseacommission.org/sargasso-sea/about-the-sargasso-sea">Early myths</a> described a treacherous section of the Atlantic Ocean where seaweed ensnared ships. Christopher Columbus documented this ecosystem in his 1492 expedition journals when his ships were becalmed there. His crew feared they would be dragged to the ocean floor, never returning home to Spain. </p>
<p>This region was sometimes called the Devil’s Triangle. Sea captains mapped routes to circumvent it completely. Mysterious accidents and disappearances there prompted author Vincent Gaddis to give it a <a href="http://www.physics.smu.edu/%7Epseudo/BermudaTriangle/vincentgaddis.txt">new name</a> in 1964: the “deadly <a href="https://www.history.com/topics/folklore/bermuda-triangle">Bermuda Triangle</a>.” </p>
<p>But these sargassum islands also create a <a href="http://www.sargassoseacommission.org/sargasso-sea/about-the-sargasso-sea">rich ecosystem</a> that ocean explorer Sylvia Earle calls “<a href="https://www.bushcenter.org/catalyst/environment/bridgeland-earle-oceans.html">a golden floating rainforest</a>.” Suspended by round “berries” filled with gas, the seaweed offers food, sanctuary and breeding grounds for crabs, shrimp, whales, migratory birds and some 120 species of fish. Mats of it form the sole spawning grounds for European and American eels and habitat for some <a href="http://www.sargassoseacommission.org/storage/documents/Sargasso.Report.9.12.pdf">43 other threatened or endangered species</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Brown Sargassum seaweed." src="https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413976/original/file-20210730-28-1ratyxj.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"></a>
<figcaption>
<span class="caption">Sargassum’s berrylike structures are gas-filled bladders that help the plant float.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/04etta/logs/aug25/media/sargassum.html">H. Scott Meister, SCDNR</a></span>
</figcaption>
</figure>
<p>Sargassum also shelters sea turtle hatchlings and juvenile fish during their early life in the open ocean. Ten endemic species live nowhere else on Earth. The Sargasso is a valuable commercial fishery worth about <a href="https://www.sargassoseacommission.org/about-the-sargasso-sea">US$100 million per year</a>.</p>
<h2>Noxious blooms</h2>
<p>Enormous amounts of sargassum first <a href="https://doi.org/10.1126/science.360.6394.1157">engulfed Caribbean coastlines</a> in 2011. I was there at the time, conducting research in the British Virgin Islands, and I saw huge “rafts” of this brown macroalgae extending 500 feet offshore. </p>
<p>Swimmers couldn’t get into the water. Some boats couldn’t leave port. Beaches were piled with massive mounds, some nearly as tall as I was. Nesting sea turtles couldn’t lay their eggs. The seaweed isn’t toxic, but as it decomposed it reeked of rotten eggs and swarmed with insects.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/whqaV8xfOTg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Beaches covered in sargassum have become the new normal in Florida and the Caribbean.</span></figcaption>
</figure>
<p>Small quantities of sargassum have always turned up as “<a href="https://myfwc.com/conservation/special-initiatives/cwci/beach-wrack/">beach wrack</a>” – stuff that washes ashore. It stabilizes shorelines by helping to build sand dunes and nourishes dune plants. For these reasons, it’s left to naturally decompose in wild areas, such as <a href="https://www.floridastateparks.org/parks-and-trails/bill-baggs-cape-florida-state-park">Cape Florida State Park</a>.</p>
<p>But the scale of recent coastal influxes is unprecedented. And since the <a href="https://doi.org/10.1080/2150704X.2013.796433">2011 event</a>, they have occurred every year except for 2013. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Maps showing sargassum belt across the Atlantic." src="https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413981/original/file-20210730-27-1tunjdf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Monthly mean sargassum density for the month of July, 2011-2018.</span>
<span class="attribution"><a class="source" href="http://dx.doi.org/10.1126/science.aaw7912">Wang et al., 2019</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Gluts of coastal seaweed have a damaging influence on the coastal environment. In large quantities, the seaweed strips oxygen from the water, killing fish and seagrasses that offer key habitat for many species. It may reduce sunlight needed by ocean plants and smother shallow coral reefs, like those in the Florida Keys.</p>
<p>In 2018 NASA satellites revealed the largest marine algae bloom in the world. <a href="https://earthobservatory.nasa.gov/images/145281/scientists-discover-the-biggest-seaweed-bloom-in-the-world">A belt of sargassum</a> that contained over 22 million tons of seaweed stretched some <a href="https://doi.org/10.1126/science.aaw7912">5,500 miles</a> across the Atlantic to West Africa. Satellite images are showing <a href="https://www.aoml.noaa.gov/phod/sargassum_inundation_report/">abnormally high amounts again in 2021</a>. </p>
<h2>Warmer, overnutrified waters</h2>
<p>Data gathered over the past decade has revealed the <a href="https://doi.org/10.1126/science.aaw7912">likely causes</a> of these seaweed invasions: Saharan dust clouds, warming temperatures and the growing human nitrogen footprint. </p>
<p>Just as nutrients feed red tide blooms, they feed sargassum, which thrives in warmer water. Climate change also increases <a href="https://doi.org/10.1038/s41598-018-21247-7">upwelling</a> of nutrients from deep ocean waters at the other end of the sargassum belt in West Africa. </p>
<p>The influxes of the past decade seem to have originated along Brazil’s Atlantic coast, not in the Sargasso Sea. Large amounts of fertilizer flow into the Amazon River and then to the ocean from <a href="https://phys.org/news/2020-08-business-booming-brazil-farmers-deforestation.html">industrial-scale agriculture</a> and ranches. Nutrients also pour into the Gulf of Mexico from the <a href="https://www.noaa.gov/news-release/noaa-forecasts-average-sized-dead-zone-for-gulf-of-mexico">Mississippi River</a>. Climate change-driven downpours increase runoff. </p>
<p><a href="http://nsgl.gso.uri.edu/flsgp/flsgpw12004/data/papers/65-17.pdf">Saharan dust clouds</a> that extend for thousands of miles across the Atlantic Ocean have also contributed to this explosion of sargassum seaweed. The dust <a href="https://www.sciencedaily.com/releases/2008/02/080206192436.htm">contains iron, nitrogen and phosphorus</a> that fertilizes plankton and seaweed blooms. These thick atmospheric dust plumes corresponded with a sargassum spike in 2015 and the worst incursion of sargassum in 2018. </p>
<p>Researchers are also exploring changing in ocean currents, which may be another contributing factor. </p>
<h2>Economic and ecological harm</h2>
<p>Sargassum threatens tourism, a major <a href="https://www.costar.com/article/1897972322">economic engine</a> for the Caribbean and Florida. Mexico has deployed Navy ships for <a href="https://www.miamiherald.com/news/local/environment/article244528867.html">cleanup operations</a> in Cancun. Some Caribbean destinations have installed floating barriers, like those used in oil spills, to keep seaweed offshore. In 2019 Prime Minister Mia Amor Mottley of Barbados likened the scale of the economic fallout to <a href="https://www.stabroeknews.com/2019/07/08/news/regional/barbados/sargassum-a-big-threat-to-caribbean-economies-barbados-pm/">that of a hurricane</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1395713911035420672"}"></div></p>
<p>There is currently no good way to dispose of such great volumes of seaweed. It’s labor-intensive and expensive. Removing sargassum from 15 miles of Miami-Dade beaches cost <a href="https://miami.cbslocal.com/2019/07/30/miami-dade-sargassum-seaweed-cleanup/">$45 million</a> in 2019. </p>
<p>[<em>Over 100,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p>
<p>Some communities plow seaweed under the sand. Others, like Fort Lauderdale, collect it, wash off the salt and convert it to natural fertilizer or mulch. In Mexico some entrepreneurs are compressing it into bricks and using it, like adobe, for <a href="https://www.travelpulse.com/news/hotels-and-resorts/mexican-hotel-to-be-built-from-bricks-made-with-sargassum.html">building construction</a>. In the long term, lasting solutions will come only through addressing climate change and nitrogen emissions from human activities.</p><img src="https://counter.theconversation.com/content/163058/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen P. Leatherman 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>Huge blooms of brown seaweed have fouled Florida and Caribbean beaches almost every year over the past decade. They originate in Africa and South America. and are fueled by human activities.Stephen P. Leatherman, Professor of Coastal Science, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1609732021-05-26T16:08:58Z2021-05-26T16:08:58ZTo protect ocean environments, ‘good enough’ might be the best long-term option<figure><img src="https://images.theconversation.com/files/401976/original/file-20210520-13-a2cwx9.JPG?ixlib=rb-1.1.0&rect=69%2C93%2C5106%2C3352&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Local support might be the most important factor for a successful marine protected area.</span> <span class="attribution"><span class="source">Anastasia Quintana</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The Gulf of California – a sea near the western border of the U.S. and Mexico – is home to some of the world’s most incredible underwater landscapes. It generates 60% of Mexico’s fish catch, but <a href="https://doi.org/10.1577/1548-8446(2004)29%5B19:FDCFWI%5D2.0.CO;2">overfishing</a> is threatening its marine ecosystems and the <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/faf.12332">people who make a living off them</a>. </p>
<p>In 2012, a number of small fishing towns set up <a href="http://dof.gob.mx/nota_detalle.php?codigo=5277968&fecha=16/11/2012">11 small, temporary areas where fishing was banned</a> to fight overfishing in the Gulf. When these marine reserves expired five years later, the towns nearby all voted on whether to keep or change them. One community, Agua Verde, voted to keep their nearby reserve of San Marcial and make it five times larger. None of the other towns expanded their reserves.</p>
<p><iframe id="dlwVv" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/dlwVv/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>We are a <a href="https://scholar.google.com/citations?user=neBHIfsAAAAJ&hl=en&oi=ao">social scientist</a> and a <a href="https://scholar.google.com/citations?user=2p_wmcoAAAAJ&hl=en&oi=ao">marine ecologist</a>, and together we study community-based fisheries management and conservation. We wanted to explore why one reserve was so successful while the others in the system were not. Our <a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.652318/full">new paper</a>, published on May 26, 2021 in the journal Frontiers in Marine Science, shows how critical community support is to conservation efforts and how smaller reserves that are “good enough” ecologically can foster that support and <a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.652318/full">lead to successful long-term conservation</a>.</p>
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<a href="https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="View looking over the bow of a boat on open water." src="https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401437/original/file-20210518-21-f1exsd.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 fisher out on the water doesn’t see the lines that define a protected area.</span>
<span class="attribution"><span class="source">Anastasia Quintana</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Lines on maps</h2>
<p>In the past 15 years, marine protected areas have become the dominant tool for marine protection. Generally speaking, these protected areas restrict or ban fishing and harvesting in an area. They currently cover <a href="https://www.protectedplanet.net/en/thematic-areas/marine-protected-areas">7.66%</a> of the ocean’s surface – about 5 billion football fields’ worth. Marine protected areas can <a href="https://doi.org/10.1038/nature21708">increase fish number and size</a>, <a href="https://doi.org/10.1371/journal.pone.0107032">rebuild nearby fisheries</a>, <a href="https://doi.org/10.1016/j.biocon.2019.05.005">build resilience against climate change</a> and even <a href="https://doi.org/10.1098/rstb.2015.0210">reduce disease in marine species</a>. </p>
<p>When conservationists and policymakers set out to design a new marine protected area, the old way of thinking was to find the <a href="https://www.iucn.org/content/how-your-mpa-doing-a-guidebook-natural-and-social-indicators-evaluating-marine-protected-areas-management-effectiveness">best location</a> for permanent protection. This focus often meant closing large areas to fishing, creating <a href="https://doi.org/10.1016/j.marpol.2020.104185">conflicts</a>.</p>
<p>Historically, this tension has <a href="https://doi.org/10.1007/s13280-019-01279-7">pitted scientists and fishers against each other</a> – not the best when fisher <a href="https://www.sciencedirect.com/science/article/pii/S0006320721000446">compliance determines the success or failure</a> of most marine protected areas. Often, “protection” amounts to nothing more than <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/aqc.2632?casa_token=EN_NY9isUK4AAAAA%3AYvhxI65zt4ac2yVm4MBYkUEgXiBNEay_FRPrA15WUe1dhaKwshLR4YRJ-UyR21NJ0g-pPXrBeuqEtw">lines on maps</a> in government offices while fishing continues unabated in the water. Even reserves that ecologists dub as successes can simultaneously be social failures, which <a href="https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.712.7345&rep=rep1&type=pdf">ultimately threatens long-term ecological outcomes</a>.</p>
<p>The 11 fishing reserves set up in the Gulf of California are an example of an alternative approach, where fishers decide what is an optimal marine reserve. Because the closures are temporary, fishers have the opportunity to test and adapt their designs over time. Instead of imposing large closures that the community might only <a href="https://doi.org/10.1007/s10750-011-0665-9">begrudgingly accept</a>, the idea was to go for something smaller that the community was excited about. Rather than being designed primarily by <a href="https://doi.org/10.1016/j.marpol.2010.09.004">scientists and policymakers</a>, local fishers – with assistance from the nonprofit conservation group <a href="https://niparaja.org/">Niparajá</a> – led the effort themselves.</p>
<h2>Two fishing communities, two levels of success</h2>
<p>Marine protected areas often create a dilemma for fishers – the best areas to protect are often also the <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12005">best to fish</a>. When Niparajá approached the communities in Baja California Sur, different towns had varying levels of trust in whether the reserves would actually improve their fisheries.</p>
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<a href="https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man holding a large blue and silver fish on a beach." src="https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401442/original/file-20210518-3808-ede7z1.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">Local fishers, though not able to fish in San Marcial, were able to see the benefits of the MPA directly.</span>
<span class="attribution"><span class="source">Anastasia Quintana</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>In the town of Agua Verde, fishers had worked with Niparajá for years. Locals trusted the conservation group’s staff so much that they were willing to turn one of their valuable fishing areas into a reserve that prohibited all fishing. Unified by strong leaders, Agua Verde’s fishers designed San Marcial, the largest protected area in the network at two square miles (5.2 square kilometers).</p>
<p>Over five years there was a 30% increase in fish biomass within the reserve. In surveys, fishers reported that catch – which had been in decline for years – had stabilized. With such tangible benefits, when the time came to update the reserve, Agua Verde made it five times larger. The town also voted to create a second marine protected area nearly as big as the first one. </p>
<p>But total local control has a weakness – when fishers don’t trust the process, they aren’t willing to give up productive fishing grounds. We saw this with the reserve at Punta Coyote. Some fishers from the communities that designed this reserve had a history of conflict with Niparajá. Multiple towns also fished the same areas in this region so it was difficult for a single leader to coordinate the communities.</p>
<p>The communities around Punta Coyote ultimately designed a tiny reserve of 0.35 square miles (0.9 square kilometers) that covered a flat, sandy bottom – poor fish habitat. Not surprisingly, there was a negligible effect on fish numbers over the five-year period. When the protection expired in 2017, the fishers renewed but didn’t expand the closed area.</p>
<p>Compared to San Marcial, the other nine reserves were closer in size to Punta Coyote and fell in the middle in terms of ecological results. Every one was renewed but not expanded.</p>
<p>We discovered several mediating factors in these processes. Leadership was essential to create a unified vision. Also, fishers needed a way to see the benefits of the reserve for themselves. Four of Agua Verde’s fishers were <a href="https://doi.org/10.1007/s10531-020-02055-w">recruited to count fish</a> in the San Marcial reserve so they observed firsthand the ecosystem recovering.</p>
<p>Ultimately, we found that community-based conservation is a self-reinforcing process that works in feedback loops. In addition, a “good enough” initial design – that is, not aiming for the maximum possible ecological benefits while still making sure the reserves result in perceptible improvements – seemed to work best. It led to conservation success that in turn led to trust and pride in – and expansion of – the protected area. However, when conflict and mistrust led to poor design without clear benefits – like what happened with Punta Coyote – fishers didn’t gain trust in the process and didn’t expand the area.</p>
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<a href="https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing a feedback loop of trust, design and ecological results." src="https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401441/original/file-20210518-3808-1sonwzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Social and ecological feedback loops can strengthen or weaken marine protected areas.</span>
<span class="attribution"><span class="source">Anastasia Quintana</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Trust leads to stronger support</h2>
<p>Our findings about San Marcial and Punta Coyote challenge the need for optimal and permanent marine protected areas. Instead, we see marine protected areas as opportunities for collective action where “good enough” might in fact be better. However, poor design or lack of leadership can lead to a downward spiral for a protected area.</p>
<p>These findings are particularly relevant this year as the <a href="https://www.cbd.int/">United Nations</a> draws up its <a href="https://www.cbd.int/conferences/post2020/post2020-prep-01/documents">biodiversity framework</a> for the next decade. The <a href="https://www.cbd.int/doc/c/3064/749a/0f65ac7f9def86707f4eaefa/post2020-prep-02-01-en.pdf">published draft document</a> calls to expand coverage from 7.66% to a whopping 30% of the global ocean. Our work suggests that in some cases, one way to achieve more numerous and more effective marine protected areas is to give real power to the people affected by protection, start small and focus on building trust and making ecological results visible. While the protected areas might start small, they can grow much larger when local communities support them.</p><img src="https://counter.theconversation.com/content/160973/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anastasia Quintana receives funding from the National Science Foundation, Duke University Graduate School, and the National Socio-Environmental Synthesis Center.</span></em></p><p class="fine-print"><em><span>Alfredo Giron Nava received funding from the Stanford Center for Ocean Solutions, the National Socio-Environmental Synthesis Center, and the American Geographical Society.</span></em></p>In the design of marine protected areas, new research suggests that it might be better to start small in order to gain local trust and support that leads to larger long-term benefits.Anastasia Quintana, Postdoctoral Research Fellow of Social, Behavioral, and Economic Sciences, University of California, Santa BarbaraAlfredo Giron Nava, André Hoffmann Fellow, Stanford UniversityLicensed as Creative Commons – attribution, no derivatives.