tag:theconversation.com,2011:/id/topics/marine-mammals-26734/articlesMarine mammals – The Conversation2023-11-24T02:53:56Ztag:theconversation.com,2011:article/2182532023-11-24T02:53:56Z2023-11-24T02:53:56ZAustralian dolphins have the world’s highest concentrations of ‘forever chemicals’<figure><img src="https://images.theconversation.com/files/561466/original/file-20231123-15-7lw4an.JPG?ixlib=rb-1.1.0&rect=89%2C19%2C4185%2C2824&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Burrunan dolphin</span> <span class="attribution"><a class="source" href="https://www.marinemammal.org.au/gallery">Marine Mammal Foundation</a></span></figcaption></figure><p>As predators at the top of the food chain, dolphins tend to <a href="https://www.sciencedirect.com/topics/chemistry/bioaccumulation#:%7E:text=Bioaccumulation%20is%20a%20process%20of,dietary%20intake%20(trophic%20transfer).">accumulate and magnify</a> high levels of toxins and other chemicals in their bodies. So health problems in dolphins can be a warning that all is not well in the system as a whole. </p>
<p>One group of persistent pollutants has been dubbed “forever chemicals” because they almost never break down in the environment. Commonly known by the acronym PFAS, these per- and polyfluorinated substances are globally recognised as an environmental hazard and a <a href="https://doi.org/10.1002/etc.4890">potential human health issue</a>.</p>
<p>In our new research, we found dolphins with the <a href="https://doi.org/10.1016/j.scitotenv.2023.168438">highest concentration of PFAS</a> in the world live in Australian waters. One young Burrunan dolphin had liver concentrations almost 30% higher than any other dolphin ever reported.</p>
<p>This is a critically endangered species endemic to southeast Australia. While the consequences for dolphin health and the implications for humans remain unknown, the record-breaking concentrations are cause for alarm. </p>
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<a href="https://theconversation.com/controversial-forever-chemicals-could-be-phased-out-in-australia-under-new-restrictions-heres-what-you-need-to-know-210697">Controversial ‘forever chemicals’ could be phased out in Australia under new restrictions. Here’s what you need to know</a>
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<h2>The case of the Burrunan dolphin</h2>
<p>The Burrunan dolphin was recognised as a <a href="https://doi.org/10.1371/journal.pone.0024047">separate species in 2011</a>. Fewer than 200 individuals remain. Two small, isolated and genetically distinct populations reside in coastal Victoria, Australia. </p>
<p>In <a href="https://doi.org/10.1016/j.scitotenv.2023.168438">our research</a>, we took liver samples from Burrunan dolphins and three other dolphin species found dead and washed up on beaches. </p>
<p>We found the critically endangered <a href="https://www.marinemammal.org.au/burrunan-dolphin">Burrunan dolphin</a> had 50–100 times more PFAS than other dolphins in the same region. Their PFAS concentrations were the highest reported globally. </p>
<p>In 90% of these dolphins, the liver concentrations of these chemicals (1,020–19,500 nanograms per gram) were above those thought to cause <a href="https://doi.org/10.1021/acs.est.5b06076">liver toxicity</a> and <a href="https://doi.org/10.1002/etc.2122">altered immune responses</a>. </p>
<p>These record-breaking and potentially health-compromising PFAS concentrations are a major concern for the survival of the species. </p>
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<a href="https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graphic illustrating the results of PFAS testing in Victorian dolphins" src="https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=232&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=232&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=232&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=291&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=291&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561478/original/file-20231124-18-4fqtj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=291&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The Burrunan dolphin had the highest global PFAS concentrations in the study.</span>
<span class="attribution"><a class="source" href="https://www.sciencedirect.com/science/article/pii/S0048969723070663?via%3Dihub">Science of The Total Environment</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Results from Australia and around the world</h2>
<p>By far the highest PFAS concentrations in the dolphins we studied were of a particular compound called PFOS (perfluorooctane sulfonate). PFOS is one of the most studied PFAS compounds. It is listed on the <a href="https://chm.pops.int/Implementation/IndustrialPOPs/PFAS/Overview/tabid/5221/Default.aspx">Stockholm Convention</a>, a global treaty on environmental pollutants, with international restrictions on use. </p>
<p>While Australia does not manufacture PFOS, heavy use of PFOS-containing firefighting foams occurred until the early 2000s. The Australian government <a href="https://www.epa.vic.gov.au/for-community/environmental-information/pfas/pfas-use-in-australia#:%7E:text=While%20PFOS%2C%20PFOA%20and%20other,as%20mist%20suppressants%20and%20coatings.">still allows PFOS import</a> for permitted purposes, such as mist suppressants in manufacturing and metal plating. </p>
<p>In recent years, public concern has prompted <a href="https://doi.org/10.1016/j.canep.2022.102296">ongoing investigations</a> into areas of high firefighting foam use, such as Royal Australian Airforce training facilities and airports. </p>
<p>While firefighting foam is a probable source of PFAS in waterways, there are others. <a href="https://theconversation.com/pfas-forever-chemicals-are-getting-into-ocean-ecosystems-where-dolphins-fish-and-manatees-dine-we-traced-their-origins-216254">Recent research in Florida</a> in the United States found leaking septic and wastewater systems in urban areas were sources of PFAS runoff into the aquatic environment. </p>
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<a href="https://theconversation.com/pfas-forever-chemicals-are-getting-into-ocean-ecosystems-where-dolphins-fish-and-manatees-dine-we-traced-their-origins-216254">PFAS 'forever chemicals' are getting into ocean ecosystems, where dolphins, fish and manatees dine – we traced their origins</a>
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<p>The Burrunan dolphins are not alone. In 2017, the <a href="https://www.epa.sa.gov.au/files/12580_report_pfas_marine.pdf">South Australian Environment Protection Authority investigated</a> PFOS concentrations in dolphins from Western Australia, South Australia and New South Wales. Dolphins in the Swan-Canning River Estuary in Perth, and in Port River or Barker Inlet, SA, had high PFOS levels (2,800–14,000ng per gram and 510–5,000ng per gram, respectively). These PFOS levels are similar to those in the Burrunan dolphin (between 494ng and 18,700ng per gram).</p>
<p>The globally significant PFAS and PFOS concentrations in multiple Australian dolphin populations demonstrates potential widespread contamination. This highlights our limited understanding of the short- and long-term consequences in our oceans and estuaries. </p>
<p>It is crucial we understand where different PFAS compounds are coming from, particularly PFOS, and whether the contamination is from a time when we didn’t know better (known as legacy sources) or if we are still releasing them. </p>
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<h2>Isn’t PFOS getting banned anyway?</h2>
<p>The Australian government has <a href="https://theconversation.com/controversial-forever-chemicals-could-be-phased-out-in-australia-under-new-restrictions-heres-what-you-need-to-know-210697">expressed an intention</a> to further regulate PFOS and two other PFAS. This marks a significant step forward. However, the problem with forever chemicals is they will be around for a really long time. </p>
<p>Typically, these chemicals are substituted with alternatives believed to be less detrimental, but unfortunately that is not always the reality. For example, early replacements for PFOS were initially thought to be less readily absorbed by body tissues and pose lower health concerns. But <a href="https://doi.org/10.1021%2Facs.est.3c00374">studies</a> have shown their high <a href="https://www.merriam-webster.com/dictionary/biomagnification">biomagnification</a> potential (with levels increasing higher up the food chain) and accompanying <a href="https://doi.org/10.1016/j.envint.2023.107846">health risks</a>.</p>
<p>While PFOS levels were highest in the Burrunan dolphins we studied, emerging contaminants such as PFMPA, PFECHS, and 6:2 Cl-PFESA were also detected. The presence of these emerging and replacement compounds in dolphins shows they are accumulating within our waterways and suggests it is more than our historic usage that might be a problem. </p>
<h2>It’s not too late</h2>
<p>Dolphins are the “canary in the coal mine” for coastal ecosystems. They live their lives in these inshore waterways and they consume tonnes of fish within their lifetimes. Finding these alarming contaminant concentrations is an important first step to highlighting the problem. </p>
<p>So now we know there’s a problem, we need to ask why. Then we need to determine what can be done about it. </p>
<p>The next step is mapping sources of PFAS so we can more effectively manage this threat to our wildlife and ecosystems. </p>
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Read more:
<a href="https://theconversation.com/we-found-long-banned-pollutants-in-the-very-deepest-part-of-the-ocean-204447">We found long-banned pollutants in the very deepest part of the ocean</a>
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<p class="fine-print"><em><span>Chantel Foord receives funding from a Holsworth Wildlife Research Endowment Grant. She is affiliated with the Marine Mammal Foundation. </span></em></p>Researchers are finding alarming concentrations of persistent pollutants such as PFAS in Australian dolphins. These record-breaking levels are cause for concern.Chantel Foord, Research Associate, Marine Mammal Foundation, PhD researcher, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2114662023-08-23T13:41:10Z2023-08-23T13:41:10ZMicroplastics discovered in the body tissues of whales, dolphins and seals – sparking concerns for human health too<figure><img src="https://images.theconversation.com/files/544261/original/file-20230823-15-p5b8on.jpg?ixlib=rb-1.1.0&rect=95%2C138%2C3387%2C2222&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Risso's dolphin entangled in fishing line.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rissos-dolphin-grampus-griseus-entangles-fishing-565450999">Andrew Sutton/Shutterstock</a></span></figcaption></figure><p>Marine mammals – animals including <a href="https://www.britannica.com/animal/whale">whales</a>, <a href="https://www.britannica.com/animal/dolphin-mammal">dolphins</a>, <a href="https://www.britannica.com/animal/seal-mammal">seals</a>, <a href="https://www.britannica.com/animal/sea-lion">sea lions</a>, <a href="https://www.britannica.com/animal/sea-otter">sea otters</a>, <a href="https://www.britannica.com/animal/dugong-mammal">dugongs</a> and <a href="https://www.britannica.com/animal/manatee">manatees</a> – are threatened by an <a href="https://www.sciencedirect.com/science/article/pii/S000632071731474X">array of human activities</a>. Species such as the <a href="https://www.worldwildlife.org/species/north-atlantic-right-whale">North Atlantic right whale</a>, <a href="https://www.fisheries.noaa.gov/species/rices-whale">Rice’s whale</a> and <a href="https://www.worldwildlife.org/species/vaquita">Vaquita porpoise</a> have been pushed to the <a href="https://www.iucnredlist.org/">brink of extinction</a>.</p>
<p>Plastic debris poses a particularly significant problem. Marine mammals mistakenly eat items such as plastic bags, food wrappers, ropes and abandoned fishing gear, or they become <a href="https://www.hindawi.com/journals/jmb/2012/684279/">entangled in plastic items</a> including fishing nets. Both scenarios can lead to injury and, in many cases, death.</p>
<p>Autopsies carried out on 34 dolphins and whales stranded along the Greek coastline in 2019 <a href="https://www.sciencedirect.com/science/article/pii/S0025326X19304230?via%3Dihub">found that</a> nine of them (from four different species) had ingested plastic – and plastic consumption was identified as the cause of death in three of these animals.</p>
<p>And now, a <a href="https://www.sciencedirect.com/science/article/pii/S026974912301254X#bib37">recent US study</a> has revealed that marine mammals face a more subtle plastic threat: microplastics. </p>
<p>In the ocean, microplastics (tiny plastic particles measuring less than 5mm) commonly accumulate in an animal’s gills or digestive tract. However, the recent study found microplastics in various other tissues of a number of different whale, dolphin and seal species. </p>
<p>This suggests that microplastic particles are somehow able to move from one part of an animal’s body to another (or “translocate”). This finding may carry health implications not only for marine mammals, but humans too.</p>
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<img alt="A pod of sperm whales in the Indian Ocean, Mauritius." src="https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=511&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=511&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543786/original/file-20230821-27-7jhehr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=511&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A pod of sperm whales in the Indian Ocean, Mauritius.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pod-sperm-whales-social-group-indian-1506432788">wildestanimal/Shutterstock</a></span>
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<h2>Contaminated tissues</h2>
<p>The researchers obtained tissue samples from 32 individual animals spanning 12 marine mammal species. These animals had either been stranded or harvested between 2000 and 2021. </p>
<p>Samples were taken from the animals’ blubber, melon (the fatty structure found in a whale’s forehead), acoustic fat pads (from the jaw), and lung tissue. These all serve vital functions such as enabling marine mammals to breathe, hear, locate prey and keep warm.</p>
<p>Analysis of the samples revealed that every single melon, acoustic fat pad and lung tissue sample contained microplastics, as did 64% of blubber samples. The particles in the tissue samples ranged from very small (24µm) to relatively large (1,387µm).</p>
<h2>Tiny particles, big impact</h2>
<p>Research has provided us with some understanding of how microplastics may affect small marine animals. At <a href="https://www.pml.ac.uk/">Plymouth Marine Laboratory</a>, we have shown that exposure to microplastic particles can affect <a href="https://www.sciencedirect.com/science/article/pii/S0269749122014580">feeding</a>, <a href="https://microplastics.springeropen.com/articles/10.1186/s43591-023-00052-8">growth</a> and <a href="https://pubs.acs.org/doi/full/10.1021/es504525u">reproduction</a> in animals that filter seawater or sediment for food.</p>
<p>Evidence of the impact of microplastics on larger animals is, by comparison, limited. This is because our understanding largely stems from observations of animals that are dead. </p>
<p>Nonetheless, studies have shown that microplastic fragments can cause the <a href="https://www.sciencedirect.com/science/article/pii/S0304389423003722#:%7E:text=Extensive%20scar%20tissue%20formation%20was,fibrosis%20in%20seabird%20stomach%20tissues.">formation of scar tissue</a> in the stomachs of seabirds. And there are also concerns that the chemicals present in marine plastic litter may <a href="https://pubs.rsc.org/en/content/articlelanding/2017/ay/c6ay02674e/unauth">leach into the tissues</a> of marine mammals upon ingestion. </p>
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Read more:
<a href="https://theconversation.com/seabirds-that-swallow-ocean-plastic-waste-have-scarring-in-their-stomachs-scientists-have-named-this-disease-plasticosis-201506">Seabirds that swallow ocean plastic waste have scarring in their stomachs – scientists have named this disease 'plasticosis'</a>
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<p>It’s therefore possible that the movement of microplastics from seawater and prey items into the tissues of marine mammals may affect their health. In the most severe scenario, the accumulation of these particles could lead to a loss of these tissues’ critical functions. However, further understanding of the implications of microplastic presence in body tissues is needed.</p>
<h2>A concern for human health?</h2>
<p>The fact that microplastics can accumulate in body tissues could also mean that more plastic particles are transferred further up the food chain to top predators like humans than is currently thought.</p>
<p>It’s generally believed that <a href="https://microplastics.springeropen.com/articles/10.1186/s43591-022-00033-3">only very small</a> microplastics (particles less than 100µm) can move from the gut or respiratory system into the bloodstream. This would limit the amount of microplastics that are consumed when eating marine vertebrates. </p>
<p>But the US study has found the presence of larger microplastic particles in non-digestive tissues, suggesting this assumption might not hold true. Separate studies in the <a href="https://www.sciencedirect.com/science/article/pii/S0045653518307240#bib27">Persian Gulf</a> and <a href="https://link.springer.com/article/10.1007/s00244-021-00885-5">Black Sea</a> have also revealed a variety of microplastic sizes present in non-digestive tissues of commercial fish. </p>
<p>Together, these findings could have implications for human health. Marine mammal meat and blubber are an important food source within certain Indigenous communities. And many people consume fish as part of their diets.</p>
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<img alt="A pilot whales being processed after a hunt." src="https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543789/original/file-20230821-29-k6they.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Marine mammal meat and blubber are important food sources for some Indigenous communities.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pilot-whales-being-processed-after-hunt-1724671597">S.Thors/Shutterstock</a></span>
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<p>The risk of ingesting microplastics from a seafood meal is, at present, <a href="https://pubs.acs.org/doi/abs/10.1021/acs.est.9b01517">lower than that</a> from drinking bottled water. But the prevalence of microplastics in the marine environment is rapidly increasing, and it is now evident that these particles can enter the bloodstream of animals and humans too. Research has found microplastic particles in <a href="https://www.sciencedirect.com/science/article/pii/S0160412022001258">human blood samples</a> and in <a href="https://www.sciencedirect.com/science/article/pii/S0160412020322297">human placenta</a>.</p>
<p>Laboratory studies have managed to highlight the generally negative impacts of microplastic exposure on small fish and invertebrates. However, we still lack a full understanding of the consequences of microplastic ingestion for larger mammals such as whales, dolphins, and humans. </p>
<p>What we are certain of is the escalating abundance of microplastics in the marine environment – our oceans are now filled with <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0281596">over 170 trillion plastic particles</a>. Efforts to stop the flow of plastic into the marine environment are urgently required.</p>
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/211466/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Garrard receives funding from NERC.</span></em></p>New research shows that relatively large microplastic particles can make their way into the body tissues of marine mammals.Samantha Garrard, Senior Marine Ecosystem Services Researcher, Plymouth Marine LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2104532023-07-26T02:35:33Z2023-07-26T02:35:33ZAn expert explains the stranding of 97 pilot whales in WA and their mysterious ‘huddling’ before the tragedy<p>Sad scenes are unfolding in Western Australia after a pod of pilot whales <a href="https://www.theguardian.com/environment/2023/jul/25/wa-mass-stranding-pilot-whales-beached-cheynes-beach-albany-caravan-park">became stranded</a> on a beach late on Tuesday. According to the latest reports, 51 of the whales have died. Some 46 remain beached and authorities are working desperately to get them back out to sea. </p>
<p>Pilot whale strandings unfortunately occur in WA, and <a href="https://www.theguardian.com/australia-news/2022/sep/27/44-pilot-whales-rescued-and-returned-to-sea-after-mass-stranding-at-tasmanian-beach">other Australian states</a>, from time to time. In recent years they have also occurred in <a href="https://www.pbs.org/newshour/science/477-pilot-whales-die-beached-on-remote-new-zealand-beaches#:%7E:text=The%20whales%20beached%20themselves%20on,at%20Waihere%20Bay%20on%20Monday.">New Zealand</a> and <a href="https://www.nytimes.com/2023/07/17/world/europe/pilot-whales-stranding-scotland.html#:%7E:text=More%20than%2050%20pilot%20whales%20died%20on%20Sunday%20after%20they,since%202011%2C%20marine%20rescuers%20say.">Scotland</a>. But this stranding is unusual because of the behaviour the whales exhibited prior to becoming beached. </p>
<p>The pod of long-finned pilot whales began congregating in the ocean off Cheynes Beach on Monday evening. They remained in a “huddle” on Tuesday, raising fears a stranding was imminent. </p>
<p>I am a marine biologist who specialises in marine mammals. I am based at the University of Western Australia’s Albany campus, about 70 kilometres from where the stranding occurred. Sadly, the chances of survival for the remaining whales is very low – and time is fast running out.</p>
<figure class="align-center ">
<img alt="a string of dead pilot whales line the beach" src="https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539411/original/file-20230726-27-i7kqyy.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">Pilot whale strandings have occurred before. Pictured: a string of dead pilot whales line the beach at Tupuangi Beach in New Zealand’s Chatham Archipelago in October last year.</span>
<span class="attribution"><span class="source">Tamzin Henderson/AP</span></span>
</figcaption>
</figure>
<h2>Understanding pilot whales</h2>
<p>There are two species of pilot whales: short-finned (which live mainly in tropical and warm-temperate regions) and long-finned (generally found in colder waters). As the name suggests, the long-finned pilot whales have longer pectoral fins than their counterparts. </p>
<p>The pilot whales stranded at Cheynes Beach are long-finned. They are generally found offshore, in the deep open ocean. We rarely see them close to the coast. This makes the species hard to study.</p>
<p>Pilot whales are, however, known to inhabit <a href="https://www.jerramungup.wa.gov.au/visit/what-to-see-do/Bremer-Bay-Canyon.aspx">Bremer Canyon</a>, a very deep ocean area 70 kilometres off the WA coast.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/about-200-dead-whales-have-been-towed-out-to-sea-off-tasmania-and-what-happens-next-is-a-true-marvel-of-nature-191340">About 200 dead whales have been towed out to sea off Tasmania – and what happens next is a true marvel of nature</a>
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</em>
</p>
<hr>
<h2>What happened at Cheynes Beach?</h2>
<p>The group of whales was spotted swimming in shallow waters at Cheynes Beach late on Monday. An official from the Department of Biodiversity, Conservation and Attractions called me on Tuesday morning, and asked about the strange huddling behaviour. I was immediately concerned. </p>
<p>Healthy pilot whales do not form huddles, so something seemed very wrong. The department’s drone footage showed the pod was forming a very tight ball, then moving into a line, then back into the ball shape. And the pod was in very shallow coastal water, which is odd. </p>
<p>We suspected the behaviour was a precursor to a stranding. The department prepared its whale stranding kit and had officials on standby in case a stranding occurred. Unfortunately, it did.</p>
<p>By 4pm on Tuesday, almost 100 whales had beached themselves. Officials monitored them overnight. By Wednesday morning, 51 had died.</p>
<p>This is unsurprising. And sadly, the chance of survival for the remaining whales is very low. Cold, windy conditions means the whales are susceptible to hypothermia. And if they are already sick – as is sometimes the case with beached whales – this combination of factors can be fatal.</p>
<p>What’s more, whales are not used to the pressure of gravity we experience on land. When whales are stranded, their organs can <a href="https://www.australiangeographic.com.au/topics/wildlife/2016/05/why-do-whales-strand-themselves/">collapse</a> due to the weight of their own body.</p>
<p>In some cases, long-finned pilot whales have been <a href="https://www.publish.csiro.au/wr/wr12023">known to survive</a> after being stranded. But time is of the essence.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1683702262462550017"}"></div></p>
<h2>Why did the whales beach themselves?</h2>
<p>In 2015, another pod of pilot whales <a href="https://www.watoday.com.au/national/western-australia/a-dozen-whales-dead-in-bunbury-harbour-20150323-1m5yf1.html">beached itself</a> in Bunbury, north of Albany. Sadly, 12 died. At the time, I and a colleague conducted necropsies – scientific examinations of animals after death – but the findings were inconclusive.</p>
<p>Whale strandings cannot be predicted and we do not know exactly why they occur. But in the case of pilot whales, their social behaviour offers some clues.</p>
<p>Pilot whales are similar to elephants in that they live in <a href="https://pubmed.ncbi.nlm.nih.gov/8480176/">tight-knit family groups</a>. It’s thought mass strandings may occur when the matriarch of the group is sick and swims into shallow water, and the others <a href="https://www.npr.org/2022/10/15/1129160306/whale-beaching-stranded-new-zealand-mystery-causes">follow</a>, or are “piloted”.</p>
<p>Whales may also become stranded due to an external stress. For example, whales use sound to communicate, navigate and search for food. Loud man-made underwater noises can <a href="https://www.cbd.int/doc/meetings/mar/mcbem-2014-01/other/mcbem-2014-01-submission-seismic-airgun-en.pdf">disrupt</a> this system.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-causes-whale-mass-strandings-72985">What causes whale mass strandings?</a>
</strong>
</em>
</p>
<hr>
<h2>What next?</h2>
<p>Officials at Cheynes Beach are trying to refloat the whales. Researchers are also taking biopsy samples and nasal swabs from the dead whales. </p>
<p>Experts will examine the swabs and samples, to try and understand more about this stranding event. I anticipate they will look for evidence of illness such as influenza or cetacean morbillivirus, as well as stress from underwater noise. </p>
<p>You might also be wondering what everyday people can do to help. If you observe marine mammals behaving unusually or getting stranded, alert authorities. And please stand aside to let authorities and other experts do their work. This is vital for the welfare of the animals and the safety of both helpers and bystanders. </p>
<p>Right now, I feel a bit helpless. I would like to be able to answer everyone’s primary question: why do pilot whales become stranded? It is a long-standing mystery in marine mammal science, and we don’t really know the answer.</p>
<p>More research is needed. Scientists need funding to attend mass strandings, collect and analyse samples and write up the findings. That gives us the best chance of piecing together this complicated puzzle. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whale-watching-guidelines-dont-include-boat-noise-its-time-they-did-199977">Whale-watching guidelines don't include boat noise. It's time they did</a>
</strong>
</em>
</p>
<hr>
<p><em>Correction: An earlier version of this article said 87 whales were stranded, rather than 97.</em></p><img src="https://counter.theconversation.com/content/210453/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Sprogis 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>Sadly, the chances of survival for the remaining whales is very low – and time is fast running out.Kate Sprogis, Adjunct Research Fellow, UWA Oceans Institute, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2062232023-05-23T16:02:49Z2023-05-23T16:02:49ZWhy are killer whales attacking boats? Expert Q&A<figure><img src="https://images.theconversation.com/files/527778/original/file-20230523-19-z9jh60.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5646%2C3769&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A killer whale in the Strait of Gibraltar.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/killer-whale-strait-gibraltar-moroccan-fishing-1705505377">Nacho Goytre/Shutterstock</a></span></figcaption></figure><p><em>Orcas living off Europe’s Iberian coast recently <a href="https://www.livescience.com/animals/orcas/orcas-have-sunk-3-boats-in-europe-and-appear-to-be-teaching-others-to-do-the-same-but-why">struck and sunk</a> a yacht in the Strait of Gibraltar. Scientists suspect that this is the third vessel this subpopulation of killer whales has capsized since May 2020, when a female orca believed to be the originator of this behaviour suffered a traumatic encounter with a boat.</em></p>
<p><em>In most reported cases, orcas are biting, bending and breaking off the rudders of sailboats. So how did they learn to imitate this behaviour – and why? We asked Dr Luke Rendell, who researches learning, behaviour and communication among marine mammals at the University of St Andrews.</em></p>
<p><strong>Why do you think orcas appear to be attacking boats off the Iberian coast?</strong></p>
<p>Any answer that I (or anyone else, really) give to this question is speculation – we just don’t know enough about killer whale motivations to be certain. The puzzle for biologists is to understand how this behaviour developed. </p>
<p>The lack of obvious fitness-enhancing rewards (like food, for example) means this is unlikely to have evolved because it enabled the whales to better survive in their environment. That is what we would call an adaptive trait: it confers a direct evolutionary benefit by helping the animal find food, mate, or successfully raise offspring. </p>
<p>But I can say what this behaviour looks like. There are multiple accounts of single and groups of orcas developing idiosyncratic and not obviously adaptive habits. These range from one group engaging in what seemed like a short-term fad of carrying dead salmon on their heads, to another vocally mimicking sea lions (there may be an adaptive outcome to convincing sea lions that you are a sea lion too, not a voracious predator, but there’s no evidence of this occurring).</p>
<p>There are other kinds of behaviour that do appear to bring rewards – for example, captive orcas learning to regurgitate fish to use as bait for gulls, which they apparently prefer to eat over the fish. But the origin and spread of these boat attacks currently fits very well with the characterisation of a temporary fad, and it remains to be seen how long it persists.</p>
<p>If instead there is an adaptive explanation, my hunch is it has to do with curiosity sometimes leading to important innovations around food sources, which can then be shared.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/KmgjWdIc7jc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p><strong>How do you suspect this behaviour is being transmitted among killer whales in the region?</strong></p>
<p>This behaviour probably started with individual orcas, but would appear to spread through social learning. We recently published a <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2018.0314">paper</a> on a similar fad-like behaviour in bottlenose dolphins, where we identified the dolphin that promoted a tail-walking behaviour it had acquired during a temporary period of captivity. </p>
<p>This is pretty similar to the account of <a href="https://onlinelibrary.wiley.com/doi/10.1111/mms.12947">an academic journal</a> on the recent yacht sinking, in that a specific individual was identified as the potential source. This orca was prompted to engage in the behaviour due to a past trauma – perhaps being struck by a boat rudder, according to the account. </p>
<p>The precise reason is very hard to know for sure, but we do know the behaviour has spread through her group. And it’s difficult to explain that dynamic without involving some kind of social learning – the spread of information.</p>
<p><strong>Is there evidence of killer whales behaving this way in the past?</strong></p>
<p><a href="https://twitter.com/_lrendell/status/1110551489569787904">I have experienced</a> orcas swimming very close to our boat in the waters near St Vincent, in the eastern Caribbean, during a research survey. Our vessel, like those involved in these interactions, was about the size of a large whale (a humpback, for instance). Maybe they were investigating us, but it never escalated to any kind of physical interaction. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black-and-white illustration of a sperm whale crunching a whaling boat in its jaws." src="https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=941&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=941&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=941&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1182&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1182&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527765/original/file-20230523-21-6opxah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1182&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An illustration from an early edition of Herman Melville’s Moby-Dick.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Moby-Dick#/media/File:Moby_Dick_p510_illustration.jpg">Augustus Burnham Shute</a></span>
</figcaption>
</figure>
<p>My impression was that they were interested in the boat’s propeller, and the currents it created – they came so close on one occasion that we had to take the engine out of gear to prevent an injury. So, approaching boats is not novel. Damaging them in such a determined way is, however, not something I have ever heard orcas do before.</p>
<p>It is, of course, known to happen in other species – notably sperm whales, giving rise to the story of Moby Dick: a combination of accounts of a white whale off the South American coast dubbed “Mocha Dick”, and the account of the whaler Essex, sunk by a large sperm whale in equatorial waters.</p>
<p><strong>The subpopulation of orcas responsible for these attacks is critically endangered. Do you think the group’s conservation status is relevant in some way?</strong></p>
<p>I don’t think it’s particularly relevant to the origin and spread of the behaviour, but it is highly relevant to how we should manage this population. </p>
<p>If these killer whales continue attacking boats, it will make protecting them harder. Not only does interacting with revolving propellers increase the risk of injury to these animals, it also threatens people – from the injuring of crews to the sinking of vessels – which will create political pressure for something to be done.</p>
<p>Of course, small vessel operators do not need to navigate the areas along the Atlantic coasts of Spain and Portugal where these interactions with orcas have been happening. Preventing them from doing so would solve the problem – but for many boat operators and owners, this is their shortest route, while heading offshore makes for riskier passages. A loss of tourism revenue if these vessels stop will add to pressure for a permanent solution.</p>
<p>It is possible that some will call for these orcas to be controlled, up to and including having them killed if they continue to threaten human life and livelihoods. This poses significant ethical questions about our relationship with these animals.</p>
<p>Should we, as the species that ultimately holds the greatest power, vacate small, vulnerable vessels from the orcas’ habitat as part of a shifting relationship to the sea, which we know is <a href="https://theconversation.com/in-hot-water-heres-why-ocean-temperatures-are-the-hottest-on-record-204534">deteriorating</a> as a result of our actions? Or should we confer on ourselves the right to navigate as we please and control any nonhuman animals that impede it, up to and including culling them? </p>
<p>Historically, the latter view would almost certainly have prevailed, and perhaps it will here. But it is a question which society, rather than scientists, must answer, and it will be telling which way the relevant authorities ultimately turn.</p>
<figure class="align-center ">
<img alt="A pod of killer whales swimming side by side." src="https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527782/original/file-20230523-15600-kktgwf.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">Boat collisions are a significant cause of death among cetaceans.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/killer-whale-orcinus-orca-408278515">Tory Kallman/Shutterstock</a></span>
</figcaption>
</figure>
<p><strong>Reports indicate a ‘traumatised’ victim of a boat collision initiated the behaviour. Are notions of solidarity and self-defence among killer whales outlandish?</strong></p>
<p>I regard this as plausible speculation. The authors of the recent paper cast it as one of a number of assumptions about how the behaviour might have developed, with generally increased pressure on their habitat and the idea of natural curiosity as other options (the latter is what I think is most likely). </p>
<p>Notions of collective self-defence in cetaceans (aquatic mammals including whales, dolphins and porpoises) are far from outlandish. We have accounts of sperm whales rising to each other’s defence when orcas attack, for example. Solidarity is a more subjective issue, and we don’t have access to the internal mental states of these animals to really understand whether this is going on.</p>
<p>I can, however, point to a different cetacean: humpback whales apparently aid other species, notably seals, that are under attack from orcas. The scientist who led the description of this behaviour, <a href="https://mmi.oregonstate.edu/people/robert-pitman">Robert Pitman</a>, said he regards it as “inadvertent altruism” based on <a href="https://www.science.org/content/article/why-did-humpback-whale-just-save-seals-life">a simple rule of thumb</a>: “When you hear a killer whale attack, go break it up.”</p>
<p>These accounts raise interesting questions about the motivations behind orcas attacking boats that we cannot yet answer. It is not impossible that these orcas perceive their own common aggressor in us – but it is also entirely possible they have no such concept.</p><img src="https://counter.theconversation.com/content/206223/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Rendell 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>Orcas appear to be imitating the behaviour of one in particular by damaging sailboat rudders.Luke Rendell, Reader in Biology, University of St AndrewsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2039592023-04-18T15:38:49Z2023-04-18T15:38:49ZHow to be sushi smart: tips on avoiding anisakis disease<figure><img src="https://images.theconversation.com/files/521270/original/file-20230417-16-akyh66.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C1756%2C1014&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nematode larvae belonging to the genus _Anisakis_ can cause the disease anisakiasis, a threat to human health.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/living-anisakis-worm-just-found-on-1142197133">Shutterstock / WH_Pics</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>From sushi and sashimi (Japan) to poke bowls (Hawaii) and ceviche (Peru), consumption of raw or undercooked fish and other seafood is becoming increasingly popular. Appealing as such dishes can be, they can also increase the risk of exposure to fish-borne parasites. </p>
<p>It’s not a matter to take lightly. Every year, almost one in ten people fall ill from eating contaminated food. The World Health Organisation estimates that some <a href="https://www.sciencedirect.com/science/article/pii/S0020751905002766">56 million cases</a> of parasitic infections associated with the consumption of fish products occur annually.</p>
<h2>Tiny but troublesome stowaways</h2>
<p>Among the fish-borne parasites that can affect humans, there are three major groups of parasitic worms, also known as <em>helminths</em>: flatworms, spiny-headed worms (acanthocephalans) and ciliated worms (nematodes).</p>
<p>Diagnoses of infection with Opisthorchis, a family of flatworms, are the most common, but they occur mainly in <a href="https://pubmed.ncbi.nlm.nih.gov/33158552/">East and Southeast Asia</a>. Of more global concern are those caused by some nematodes of the family Anisakidae, particularly species of the genera <em>Anisakis</em>, <em>Pseudoterranova</em> and <em>Contracaecum</em>. As a consequence, they’re the focus of much of the world’s medical and economic concern.</p>
<p>The parasitic disease <a href="https://www.cdc.gov/parasites/anisakiasis/index.html">anisakiasis</a>, caused by nematode larvae belonging to the genus <em>Anisakis</em>, is considered the main threat to human health. Every year and on all continents, countless cases are diagnosed in humans, in part because the rise in consumption of foods such as sushi and sashimi. In Japan alone, where it is traditional to eat raw fish and seafood dishes, more than <a href="https://pubmed.ncbi.nlm.nih.gov/33025215/">7,000 cases of anisakiasis occur annually</a>.</p>
<h2>From marine mammals to human stomachs</h2>
<p>Today, anisakiasis is not only an emerging global human health problem, but it is also an economic concern, due to the potential negative effects on consumer confidence and trade associated with infected fish products.</p>
<p>So how can this troublesome disease be avoided? The answer lies in understanding the parasites’ life cycle.</p>
<p>The genus <em>Anisakis</em> comprises nine species, three of which (<em>Anisakis simplex</em>, <em>Anisakis pegreffii</em> and <em>Anisakis physeteris</em>) have been confirmed as zoonotic pathogens. These nematodes infect a wide range of marine organisms; fish and cephalopods serve as intermediate hosts, while dolphins, whales, seals and other marine mammals are the <a href="https://www.nature.com/articles/s41598-022-17710-1">final hosts</a>.</p>
<p>Adult worms are found in the mucous membrane that lines the stomachs of marine mammals. The parasite’s eggs are expelled along with the animal’s faeces and hatch in seawater. There, krill – small crustaceans that form the basis of the ocean food chain – eat them and become infected with larval stages of the nematodes. When the krill are in turn eaten by fish or squid, another stage of larvae infects the predators’ guts and become embedded on the surface of their organs and eventually in their muscles.</p>
<p>And that’s where we humans come in. When we consume fish, squid, octopus or other seafood containing <a href="https://www.cdc.gov/parasites/anisakiasis/biology.html">third-stage <em>Anisakis</em> larvae</a> that’s raw or undercooked, we can become accidental hosts to <em>Anisakis</em> larvae. Once ingested, they settle in our stomach and sometimes the small intestine.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518175/original/file-20230329-14-yedtuz.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"></span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/parasites-under-microscope-woman-suffering-helminthiasis-2223896623">New Africa/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Stomach pain and worse</h2>
<p>While the parasite cannot reproduce in humans, it can survive for a short period of time and cause anisakiasis, which can range from mild to severe depending on the person infected. The most typical symptoms of gastric anisakiasis include abdominal pain, nausea and vomiting within hours of ingesting the larvae. Other symptoms can include <a href="https://pubmed.ncbi.nlm.nih.gov/25039016/">allergic reactions</a> and even <a href="https://www.mayoclinic.org/diseases-conditions/anaphylaxis/symptoms-causes/syc-20351468">anaphylactic shock</a>. Infection of the small intestine is less common, but when it occurs it can result in an inflammatory mass and symptoms similar to <a href="https://www.niddk.nih.gov/health-information/digestive-diseases/crohns-disease">Crohn’s disease</a>, which develops one to two weeks later.</p>
<p>Some workers in the fishing industry as well as cooks and other professionals who regularly deal with fish may suffer from occupational allergic anisakiasis. Here, ingestion of the parasite’s larvae is not necessary for the disease to occur – those affected become <a href="https://pubmed.ncbi.nlm.nih.gov/28429304/">sensitive to <em>Anisakis</em> proteins</a> that come into contact with the skin or respiratory tract.</p>
<p>Thankfully, the overall prognosis for anisakiasis is generally positive. Most infections are self-limiting and usually resolve spontaneously after several weeks. Person-to-person transmission is effectively impossible.</p>
<h2>Ceviche, sashimi and even pickled anchovies</h2>
<p>More than 90% of anisakiasis cases worldwide are reported in Japan, and most of the remaining 10% in countries such as Spain, Italy, the United States (Hawaii), the Netherlands and Germany. These are regions where we traditionally eat raw or undercooked fish dishes such as sushi and sashimi, ceviche and carpaccio, <a href="https://www.sciencedirect.com/science/article/pii/S0034528823000607">pickled or pickled anchovies</a>, Hawaiian-style <a href="https://en.wikipedia.org/wiki/Lomi-lomi_salmon">salmon lomi-lomi</a> and salted herring. The species that are <a href="https://www.sciencedirect.com/science/article/pii/S0078323422000446">most frequently parasitised</a> include salmon, tuna, squid, cod, hake, mackerel, mackerel, horse mackerel, blue whiting, sardines and anchovies.</p>
<p>How can anisakiasis be prevented? Preventive measures are essential to control and minimise the disease. While the worms can resist pickling and smoking, semi-preserves such as anchovies and traditionally salted dried fish such as cod or mojamas involve processes that kill the parasite. The best approach is to use a traditional cooking technique such as cooking, frying, baking or grilling. The <a href="https://www.aesan.gob.es/AECOSAN/web/seguridad_alimentaria/subdetalle/anisakis.htm">Spanish Agency for Food Safety and Nutrition</a> reports that when the cooking temperature of a seafood reaches or exceeds 60°C (140 Fahrenheit) for at least one minute, the parasite is killed.</p>
<p>While such methods aren’t an option for fans of sushi, sashimi, and ceviche, freezing is. When seafood is subjected to -20°C for seven days or -35°C for more than 15 hours, the <a href="https://pubmed.ncbi.nlm.nih.gov/32247867/">larvae are destroyed</a>. If you’re not sure that your freezer can go that low, it’s prudent to buy frozen fish. Indeed, to increase consumer food safety, in some countries, commercially prepared sushi is frozen before being sold.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=150&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=150&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=150&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=189&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=189&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521606/original/file-20230418-24-ei0c1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=189&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 coiled anisakid worm (<em>Pseudoterranova decipiens</em>) in a fillet of cod. Center: The head end of <em>Pseudoterranova decipiens</em>. Right: A <em>Pseudoterranova decipiens</em> recovered from a human patient.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/parasites/anisakiasis/index.html">DPDx/CDC</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p><a href="https://food.ec.europa.eu/system/files/2016-10/biosafety_fh_eu_food_establishments-20111214_scfcah_guidance_parasites_en.pdf">European legislation</a> requires that seafood not be offered for sale with visible parasites. To avoid anisakiasis, it’s advisable to buy clean and gutted fish and to visually inspect them – even fish fillets merit examination. </p>
<p>There are a few exceptions from the freezing requirement. Oysters, mussels, clams, and other molluscs; fish from inland waters (rivers, lakes, marshes…) and freshwater fish farms (trout and carp, for example). Farm-raised fish may also be safe, providing that they were reared from embryos obtained in captivity, fed with feed without zoonotic parasites, and kept in a parasite-free environment.</p>
<p>While there’s much to be aware of, it’s better than suffering the consequences of inattention or inaction. With the correct steps and a measure of precaution, it’s possible to enjoy seafood in a safe and responsible way.</p><img src="https://counter.theconversation.com/content/203959/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raúl Rivas González ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Raw seafood dishes such as sushi, poke bowls and ceviche are increasingly popular, but can harbour fish-borne parasites. What’s the best way to protect ourselves?Raúl Rivas González, Miembro de la Sociedad Española de Microbiología. Catedrático de Microbiología, Universidad de SalamancaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2013682023-03-09T05:01:46Z2023-03-09T05:01:46ZPenguin paradise and geological freak: why Macquarie Island deserves a bigger marine park<figure><img src="https://images.theconversation.com/files/514116/original/file-20230308-24-ho6ma5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5240%2C3404&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Agami/Marc Guyt</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Macquarie Island, around 1,500km southeast of Tasmania, is more than just a remote rocky outcrop. In fact, it’s the only piece of land on the planet formed completely from ocean floor, which rises above the waves to form peaks that teem with penguins and other bird species, some of them found nowhere else on Earth. </p>
<p>These are just some of the reasons why this unique island, and the seas that surround it, have globally significant conservation values. Our new <a href="https://zenodo.org/record/7623378">independent assessment</a> of these values forms the scientific evidence base of Federal Environment Minister Tanya Plibersek’s <a href="https://minister.dcceew.gov.au/plibersek/media-releases/macquarie-island-marine-park-poised-triple-size">announcement last month</a> of plans to significantly increase protections for the waters surrounding Macquarie Island. </p>
<p>By comprehensively assessing the available data on the marine ecosystems and the many species that live on and around Macquarie Island, our report reveals a subantarctic environment that is crucial for breeding and feeding for millions of seabirds and thousands of marine mammals.</p>
<p>Macquarie Island and its surrounding seas (to a distance of 5.5km) are already protected as a <a href="https://parks.tas.gov.au/explore-our-parks/macquarie-island-world-heritage-area">Tasmanian reserve</a>, and the area (this time including seas to a distance of 22km) is also a <a href="https://whc.unesco.org/en/list/629/">World Heritage Area</a>. A Commonwealth marine park also covers most of the southeast quadrant of the island’s “<a href="https://en.wikipedia.org/wiki/Exclusive_economic_zone">economic exclusion zone</a>”, including a sanctuary zone and two seafloor management zones. </p>
<p>The federal government’s proposed expansion of the marine park would cover the island’s entire economic exclusion zone, increasing the area of Australia’s marine sanctuaries by more than 388,000 square kilometres, an increase larger than the area of Germany.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of marine park" src="https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=522&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=522&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=522&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=656&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=656&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514389/original/file-20230309-14-7ethaq.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=656&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 existing marine park (green), and the proposed expansion (yellow).</span>
<span class="attribution"><span class="source">Australian government</span></span>
</figcaption>
</figure>
<h2>An outstanding spectacle</h2>
<p>Macquarie Island is the exposed crest of the 1,600km-long undersea Macquarie Ridge, which makes Macquarie Island the only piece of land in the world formed entirely of oceanic crust. </p>
<p>Macquarie Ridge is one of only three such ridges that impede the eastward flow of a current called the <a href="https://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current">Antarctic Circumpolar Circulation</a>, resulting in distinct differences between the west and east sides of the ridge, which are used in different ways by different species. </p>
<p>The oceanography is further divided north to south by two major <a href="https://en.wikipedia.org/wiki/Front_(oceanography)">ocean fronts</a>, the Sub-Antarctic Front and the Polar Front, creating three distinct bodies of water. They are closer here than anywhere else in the Southern Ocean, and as they interact with the Macquarie Ridge create at least six different large-scale oceanographic habitats. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Huge colony of birds on foggy hillside" src="https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514385/original/file-20230309-24-btz5n2.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 haven for penguins and other seabirds.</span>
<span class="attribution"><span class="source">Agami/Marc Guyt</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This creates an outstanding spectacle of wild, natural beauty and a diverse set of habitats supporting vast congregations of wildlife, including penguins and seals. Fifty-seven seabird species, including four species of penguins and four species of albatross, have been recorded on Macquarie Island, and 25 of these species have been observed breeding there. The royal penguin and the Macquarie Island imperial shag live nowhere else on Earth.</p>
<p>The ridge includes a series of undersea mountains that act as “stepping stones” linking subantarctic and polar animals on the sea floor, <a href="https://www.science20.com/news_releases/brittlestar_city_underwater_summit_taller_than_the_world_s_tallest_building">such as brittlestars</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/enjoy-them-while-you-can-the-ecotourism-challenge-facing-australias-favourite-islands-152679">Enjoy them while you can? The ecotourism challenge facing Australia's favourite islands</a>
</strong>
</em>
</p>
<hr>
<h2>Needing more protection</h2>
<p>Our report shows the area around Macquarie Island is not well represented by the current marine park. In particular, the entire area to the west, and most of the northern and southern parts of the Macquarie Ridge, are not protected by the current marine park, but will be included in the proposed expansion. </p>
<p>Our report also considers several options for protecting the area’s unique ecosystems and concludes that the most sensible approach, given the available data, would be to declare the whole area around the Macquarie Ridge as a marine park, increasing the protection outside the current sanctuary zone, while allowing the current fishery to continue in a habitat protection zone. </p>
<p>This provides the simplest, most expeditious reserve design that is relatively easy to implement, achieves environmental protection and sustainable fishing, recognises the importance of the entire Macquarie Island region, and provides the most resilience to climate change. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blue sign on foggy hillside" src="https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514386/original/file-20230309-22-ri9b9d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The island is already a nature reserve, but its surrounding waters need greater protection.</span>
<span class="attribution"><span class="source">Agami/Marc Guyt</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Direct human impacts in the area are predominantly due to fishing and marine debris, although climate change is an ever-present threat too. The fishery targets the deepwater Patagonian toothfish using bottom longlines, mostly in the central zone of the Macquarie Ridge. This fishery is generally well regarded for its best-practice fishing methods and commitment to positive environmental outcomes, and this fishing activity would continue under the new plans. </p>
<p>But if new fisheries were allowed to develop targeting midwater species, or new industries such as seabed mining were permitted, these could directly impact the seabirds, marine mammals and other species that live in these areas. </p>
<p>The proposal put forward by Minister Plibersek protects all of the Commonwealth waters in two different zones of a marine park, effectively tripling the size of the current marine park. It protects the marine domain and allows the current fishery to continue without significant changes to current practices or catches. </p>
<p>Restrictions on any potential future fisheries would be determined by the distribution of “sanctuary zones” which would preclude fishing, and “habitat/species zones”, which could accommodate sustainable fishing. Mining would be precluded under either category of protection.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/disruption-over-macquarie-island-calls-for-some-clever-antarctic-thinking-65558">Disruption over Macquarie Island calls for some clever Antarctic thinking</a>
</strong>
</em>
</p>
<hr>
<h2>What next?</h2>
<p>The government’s proposal signals a clear priority for protection over development in this area. A period of public consultation on the proposal will commence in March. Any future development of the marine park would need to be orderly and careful, including prior consideration of environmental impacts. Any changes to the current fishery management arrangements should ensure that the changes maintain or enhance conditions for a long-term sustainable fishery.</p>
<p>More broadly, our report also demonstrates the potential for, and importance of, compiling the most up-to-date available data for any region prior to any formal review process to update Australia’s marine park network.</p>
<hr>
<p><em>The authors thank Anthony D. M. Smith for his contribution to this article and the report on which it’s based.</em></p><img src="https://counter.theconversation.com/content/201368/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Cresswell received funding from the Australian Marine Conservation Society and the Pew Charitable Trusts. </span></em></p><p class="fine-print"><em><span>Andrew John Constable has received Funding from the Australian Marine Conservation Society and Pew Charitable Trusts.</span></em></p><p class="fine-print"><em><span>Nic Bax has received funding from the Australian Marine Conservation Society and the Pew Charitable Trusts</span></em></p><p class="fine-print"><em><span>Keith Reid 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>Macquarie Island isn’t just a windswept rock halfway to Antarctica. It’s a globally unique home to dozens of bird and marine mammal species, hence the government’s plans to give it greater protection.Ian Cresswell, Adjunct professor, UNSW SydneyAndrew J Constable, Leader, Southern Ocean Ecosystem Research, University of TasmaniaKeith Reid, Honorary Research Associate, Institute for Marine and Antarctic Studies, University of TasmaniaNic Bax, Director, NERP Marine Biodiversity Hub, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1980902023-01-19T06:11:41Z2023-01-19T06:11:41ZOffshore wind farm construction is noisy – but gadgets used to protect marine mammals are working<figure><img src="https://images.theconversation.com/files/505122/original/file-20230118-22-euadqv.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4595%2C3061&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Harbour porpoises are the most common toothed whale in the turbine-rich North Sea.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/harbour-porpoise-phocoena-2137783321">Onutancu/Shutterstock</a></span></figcaption></figure><p><a href="https://energy.ec.europa.eu/topics/renewable-energy/offshore-renewable-energy_en#:%7E:text=The%20deployment%20of%20offshore%20wind,the%205%20EU%20sea%20basins.">The European Union</a> had 14.6 gigawatts (GW) of offshore wind energy installed in 2021, and this is projected to increase by at least 25 times in the next ten years. While an expanding renewable energy sector is necessary to replace fossil fuels and slow climate change, it must not come at a cost to <a href="https://theconversation.com/uk/topics/biodiversity-486">Earth’s embattled wildlife</a>. </p>
<p>To date, most offshore wind turbines have been built using fixed foundations, typically steel piles that are driven into the seabed with hydraulic hammers – often very large ones. The noise that pile-driving generates can be heard tens of kilometres from the source as short and sharp concussions like gunfire.</p>
<p>Sound travels much more efficiently in water than in air. Marine mammals like whales and porpoises use it to communicate over long distances, sense the environment and locate prey. This dependence on sound makes marine mammals <a href="https://doi.org/10.1644/07-MAMM-S-307R.1">particularly vulnerable</a> to the effects of man-made noise, including the noisy construction of offshore wind farms. Pile-driving can deafen, injure or even kill marine mammals at close range.</p>
<p>The harbour porpoise is the smallest and <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.606609">most common</a> species of cetacean in the North Sea, where EU countries hope to generate <a href="https://windeurope.org/policy/joint-statements/the-esbjerg-offshore-wind-declaration/">150 GW</a> of offshore wind energy by 2050. Like bats, these relatives of whales and dolphins emit clicks to echolocate almost continuously. This helps them find and identify objects, including food. Acoustic deterrents, small devices which emit pulses of sound, are used to scare marine mammals away from where wind farms are being built to protect them from the noise generated by pile-driving. Until recently though, no one was sure how well these deterrents worked.</p>
<figure class="align-center ">
<img alt="The dorsal fins and backs of two harbour porpoises emerging from the water." src="https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505126/original/file-20230118-14-1r7n63.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">Harbour porpoises, as the name suggests, are found in coastal waters.</span>
<span class="attribution"><span class="source">University of Aberdeen</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>My colleagues at the University of Aberdeen’s Lighthouse Field Station and the University of St. Andrews’ Sea Mammal Research Unit developed <a href="https://doi.org/10.1098/rsbl.2022.0101">a portable acoustic recorder</a> which can detect the movements of harbour porpoises. Using an array of these recorders during pile-driving at an offshore wind farm in north-east Scotland, we showed that acoustic deterrents work – porpoises swim directly away from the pulses of sound, ameliorating the most severe impacts of construction at sea. </p>
<h2>Fighting noise with noise</h2>
<p>A range of <a href="https://doi.org/10.3390/jmse9080819">measures</a> have been deployed to minimise the harm from offshore wind farm construction. Acoustic deterrent devices, which are switched on before pile-driving begins, are supposed to empty the sea of marine mammals tens to hundreds of metres around the construction site, where the noise is expected to be most damaging. These <a href="https://doi.org/10.3354/meps10482">electronic devices</a> were originally developed for use in the aquaculture industry to deter seals from fish farms.</p>
<figure class="align-center ">
<img alt="A wind turbine on a yellow platform in the ocean." src="https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505128/original/file-20230118-22-rpeyaq.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">
<figcaption>
<span class="caption">Offshore wind turbine foundations are driven into the seabed.</span>
<span class="attribution"><span class="source">University of Aberdeen</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Despite <a href="https://doi.org/10.3354/MEPS10100">experimental trials</a>, there is limited evidence to show how well acoustic deterrents work during construction. This is, at least in part, due to the difficulties of working in the marine environment, but also because of the challenges involved in studying animals that are highly mobile, relatively rare and live most of their lives underwater and out of sight. These factors make it very hard to observe how marine mammals react to particular noises or disturbances. Fortunately, we were able to turn the dependence of harbour porpoises on sound to our advantage.</p>
<p>Recent advances in <a href="http://dx.doi.org/10.1371/journal.pone.0229058">passive acoustic monitoring</a> meant that we could use a sound recorder connected to a small cluster of underwater microphones, called hydrophones, to study porpoise movements. By measuring tiny differences in the time of arrival of porpoise echolocation clicks at the four hydrophones, we identified the direction from which they were echolocating. The harbour porpoise’s echolocation beam is <a href="https://doi.org/10.1121/10.0001376">narrow and forward-facing</a>, and so from these findings, we were able to determine the direction in which they were swimming.</p>
<figure class="align-center ">
<img alt="A drum covered in electronic devices is lowered over the side of a boat into the ocean." src="https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505120/original/file-20230118-20-8vvg3x.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A hydrophone cluster being deployed.</span>
<span class="attribution"><span class="source">University of Aberdeen</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We found that when acoustic deterrents were in use, the clicks of harbour porpoises we detected indicated they were swimming directly away from the construction site. This proves that acoustic deterrent devices can make offshore wind farm construction safer. </p>
<p>We did detect responses among harbour porpoises up to 7 km from the construction site, suggesting that these deterrent devices may be almost too good at their job. Such a long-distance effect could displace animals from important feeding sites and highlights the importance of a balance between preventing injuries and minimising disturbance.</p>
<p>Our portable acoustic recorder can now improve protection for marine mammals by more accurately determining how they respond to disturbance across a wide range of habitats. It will also allow researchers to gauge the effectiveness of measures used to minimise disturbance during wind farm construction or other activities, including animal deterrents and systems for reducing the noise produced by piling at construction sites.</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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<hr><img src="https://counter.theconversation.com/content/198090/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Isla Graham received funding from Moray Offshore Wind Farm (East) Ltd. The funding body had no input in data collection, data analysis or interpretation. The aims, scope and experimental design of the study were developed by the authors to meet Moray Offshore Wind Farm (East) Ltd planning consent conditions. These were agreed by the regulator Marine Scotland Licensing and Operations Team following consultation with statutory advisors represented on the Moray Firth Regional Advisory Group (MFRAG), a stakeholder group that was established by the Scottish government to oversee the monitoring programme.</span></em></p>A new acoustic recorder could track the movements of marine mammals more accurately.Isla Graham, Research Fellow, School of Biological Sciences, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1974322023-01-17T12:31:09Z2023-01-17T12:31:09ZUnderwater noise is a threat to marine life<p>Oceans are full of sound. Waves, earthquakes and calving icebergs all contribute to the underwater soundscape. But so do human activities, and this can be a problem for marine life as it can seriously affect their physiology, behaviour, reproduction and even survival.</p>
<p>Being able to produce and detect sound in an environment where light penetrates only a few hundred metres is crucial for animals to communicate, feed, avoid predators and navigate vast underwater habitats. Large whales generate low frequency communication calls that can travel <a href="https://www.bbcearth.com/news/the-loudest-voice-in-the-animal-kingdom">thousands of kilometres</a>. While the <a href="https://www.science.org/doi/full/10.1126/science.289.5487.2114">snapping shrimp</a>, native to the western Atlantic, can produce a loud snapping sound capable of stunning and killing its prey.</p>
<p>The noise generated by humans <a href="https://www.science.org/doi/10.1126/science.aba4658">changes the natural acoustic environment</a> of our oceans and our capacity to produce it is increasing. Noise is often the unintentional byproduct of transport, infrastructure development and industry. </p>
<p>Yet noise can also be produced deliberately. Many navies use sonar to detect ships and submarines, while geologists survey the seabed for oil and gas using <a href="https://dosits.org/animals/effects-of-sound/anthropogenic-sources/seismic-airguns/">seismic airguns</a>. The noise produced by an airgun can exceed 200 decibels (louder than a gunshot at a range of one metre).</p>
<p>Sound travels further and <a href="https://en.wikipedia.org/wiki/Speed_of_sound">four times faster</a> in water than in air (at a speed of almost 1,500 metres per second). The noise produced by humans can therefore spread considerable distances underwater. These sounds can be relatively constant, such as the noise produced by a ship’s engine and propeller, or sudden and acute in the case of naval sonar and seismic airguns. </p>
<h2>Can noise kill?</h2>
<p>The sound produced by a seismic airgun can cause permanent hearing loss, tissue damage and even death in nearby animals. </p>
<p>Evidence for the lethal effects of noise can be hard to document in the open ocean. But seismic surveys have been linked to the mass mortality of <a href="https://tethys.pnnl.gov/publications/review-records-giant-squid-north-eastern-atlantic-severe-injuries-architeuthis-dux">squid</a> and <a href="https://academic.oup.com/bioscience/article/68/12/1024/5160052">zooplankton</a>. In 2017, research revealed that a single air gun caused the death rate of zooplankton to increase from 18% to 40–60% over a 1.2 kilometre stretch of the ocean off the coast of southern Tasmania.</p>
<p>The use of <a href="https://www.sciencedirect.com/science/article/pii/S0025326X08002221">naval sonar</a> has also been associated with the mass stranding of several whale species in the Caribbean, Europe and East Asia. Mass stranding events involve entire pods of animals simultaneously beaching themselves. </p>
<p>Examination of the dead whales revealed they had suffered trauma similar to decompression sickness. This was believed to have been caused by sudden changes in their deep diving behaviour following exposure to sonar. </p>
<h2>Arrested development</h2>
<p>Over the past two decades, research has also revealed the widespread impact of chronic noise exposure on <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12207">animal behaviour and physiology</a>. These impacts can extend well beyond the noise source and affect vast areas of the ocean. </p>
<p><a href="https://www.nature.com/articles/srep05891?origin=ppub">Laboratory studies</a> on the <a href="https://oceaninfo.com/animals/sea-hare/">sea hare</a> – a marine slug – revealed that exposure to boat noise led to a 21% reduction in successful embryo development. Individuals that hatched also suffered a 22% higher death rate than sea hares that were not exposed to boat noise. </p>
<p>These findings demonstrate the negative effects that a common source of underwater noise can have on animal development and survival. If these laboratory results can be applied to natural environments then such impacts could threaten entire populations of marine species in particular areas.</p>
<figure class="align-center ">
<img alt="A sea hare attached to a rock underwater." src="https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504284/original/file-20230112-14-f24d9d.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">Embryonic development in sea hares was reduced when exposed to boat noise.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/underwater-shot-on-large-sea-hare-1807396141">Vojce/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Disrupted behaviour</h2>
<p>Observing the movements, feeding, communication, resting and social interactions of animals provides scientists with a method for exploring the <a href="https://theconversation.com/how-noise-pollution-is-changing-animal-behaviour-52339">effects of noise</a>. </p>
<p>The behavioural impacts of noise on marine mammals are particularly well studied due to conservation concerns and their reliance on sound for communication, foraging and navigation. Many of these species move large distances and long-range communication is crucial for coordinating social interactions and reproduction. </p>
<p>But the sounds produced by large marine mammals are of a similar low frequency range to much of the noise produced by humans. The noise produced by ships tends to be <a href="https://www.sciencedirect.com/science/article/pii/S0025326X20300667">below 2 kHz</a> which overlaps with the vocal frequencies produced by many large mammals. <a href="https://asa.scitation.org/doi/10.1121/1.1593066">Blue whales</a>, for example, produce frequency vocalisations of less than 100 Hz meaning their calls can be lost in the background din.</p>
<p>Shipping noise has led to marine mammals altering their vocalisation patterns. This includes making calls longer and more repetitive or waiting until noise levels drop before calling. Research has shown that shipping noise made within 1,200 metres of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204112">humpback whales</a> has caused the whales to either reduce or stop their calling in the waters surrounding the remote <a href="https://whc.unesco.org/en/list/1362/">Ogasawara Islands</a> in Japan.</p>
<p>Despite these vocal adaptations, noise can negatively affect animals’ feeding behaviour and increase physiological stress. <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2011.2429">Research</a> found that a reduction in shipping following the 9/11 terrorist attacks led to a six decibel drop in noise levels in the Bay of Fundy on Canada’s Atlantic coast. This coincided with lower levels of physiological stress detected in <a href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale">North Atlantic right whales</a> when researchers measured stress hormones from floating whale faeces.</p>
<p>The COVID-19 lockdowns also led to previously busy waterways being used more frequently by large marine animals. For example, dolphin numbers – including the endangered <a href="https://www.reuters.com/article/health-coronavirus-hongkong-dolphins-idINKBN2650B0">pink dolphin</a> – increased in the waters around Hong Kong following temporary restrictions on ferry traffic.</p>
<p>Noisy oceans are having a profound negative impact on marine life. Taking action to protect and restore natural soundscapes is a key priority for conservation. </p>
<p>The good news is that noise is removed from the environment as soon as the sound source is switched off or turned down. Technological developments in ship design, such as <a href="https://www.rivieramm.com/opinion/opinion/a-quiet-revolution-in-underwater-noise-54783">reduced propellor cavitation</a> (the formation of air bubbles on the surface of a propeller), have already <a href="https://www.sciencedirect.com/science/article/pii/S0003682X18300021">lowered</a> the noise produced by ships. </p>
<p>Small adjustments in speed can also substantially lower engine and propeller noise. <a href="https://web.p.ebscohost.com/abstract?site=ehost&scope=site&jrnl=17183200&AN=95846538&h=HnGgvltyT4fzxuRUwoAFioh3Q8aXl41naC8CF7n6px%2bSTWTrT9CpM2Tv6UJlU393O3pCtkmBJVmdLpkHgB0NsQ%3d%3d&crl=c&resultLocal=ErrCrlNoResults&resultNs=Ehost&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d17183200%26AN%3d95846538">Research</a> has found that a 15.6 to 13.8 knot reduction in the average speed of commercial ships can reduce underwater noise pollution by more than 50%. </p>
<p>But global awareness of the impact of noise on ocean health needs improving and policies aimed at managing sound and implementing technological solutions must be more rigorous. These are readily available solutions that promise a brighter – and quieter – future for our oceans.</p><img src="https://counter.theconversation.com/content/197432/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Graeme Shannon 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>Noisy oceans are having a significant impact on marine life.Graeme Shannon, Lecturer in Zoology, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1883322022-08-23T12:24:02Z2022-08-23T12:24:02ZDolphins use signature whistles to represent other dolphins – similarly to how humans use names<figure><img src="https://images.theconversation.com/files/479186/original/file-20220815-11-q79gbl.jpg?ixlib=rb-1.1.0&rect=120%2C699%2C4365%2C2869&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bottlenose dolphins are extremely social animals that communicate constantly.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/dolphins-underwater-royalty-free-image/89619678?adppopup=true">Micha Pawlitzki/Corbis Documentary via Getty Images</a></span></figcaption></figure><p>Bottlenose dolphins’ signature whistles just passed an important test in animal psychology. A new study by my colleagues and me has shown that these animals may use their whistles as namelike concepts.</p>
<p>By presenting urine and the sounds of signature whistles to dolphins, my colleagues <a href="https://scholar.google.com/citations?user=KhKIWqcAAAAJ&hl=en&oi=ao">Vincent Janik</a>, <a href="https://scholar.google.com/citations?user=LdOMUTYAAAAJ&hl=en&oi=ao">Sam Walmsey</a> and <a href="https://scholar.google.com/citations?user=Z9Z9u2EAAAAJ&hl=en&oi=ao">I</a> recently showed that these whistles <a href="https://doi.org/10.1126/sciadv.abm7684">act as representations of the individuals who own them</a>, similar to human names. For behavioral biologists like us, this is an incredibly exciting result. It is the first time this type of representational naming has been found in any other animal aside from humans.</p>
<h2>The meaning of a name</h2>
<p>When you hear your friend’s name, you probably picture their face. Likewise, when you smell a friend’s perfume, that can also elicit an image of the friend. This is because humans build mental pictures of each other using more than just one sense. All of the different information from your senses that is associated with a person converges to form a mental representation of that individual - a name with a face, a smell and many other sensory characteristics.</p>
<p>Within the <a href="https://doi.org/10.1080/09524622.1997.9753352">first few months of life</a>, dolphins invent their own specific identity calls – called <a href="https://doi.org/10.1038/207434a0">signature whistles</a>. Dolphins often announce their location to or greet other individuals in a pod by sending out their own signature whistles. But researchers have not known if, when a dolphin hears the signature whistle of a dolphin they are familiar with, they actively picture the calling individual. My colleagues and I were interested in determining if dolphin calls are representational in the same way human names invoke many thoughts of an individual.</p>
<p><audio preload="metadata" controls="controls" data-duration="1" data-image="" data-title="Dolphins use signature whistles to identify themselves." data-size="32290" data-source="Jason Bruck" data-source-url="" data-license="CC BY-ND" data-license-url="http://creativecommons.org/licenses/by-nd/4.0/">
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Dolphins use signature whistles to identify themselves.
<span class="attribution"><span class="source">Jason Bruck</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a><span class="download"><span>31.5 KB</span> <a target="_blank" href="https://cdn.theconversation.com/audio/2569/dolphin-1-signature-whistle.m4a">(download)</a></span></span>
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<p><audio preload="metadata" controls="controls" data-duration="1" data-image="" data-title="No two signature whistles are the same." data-size="47219" data-source="Jason Bruck" data-source-url="" data-license="CC BY-ND" data-license-url="http://creativecommons.org/licenses/by-nd/4.0/">
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No two signature whistles are the same.
<span class="attribution"><span class="source">Jason Bruck</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a><span class="download"><span>46.1 KB</span> <a target="_blank" href="https://cdn.theconversation.com/audio/2570/dolphin-2-signature-whistle.m4a">(download)</a></span></span>
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<p>Because <a href="https://www.elsevier.com/books/anatomy-of-dolphins/cozzi/978-0-12-407229-9">dolphins cannot smell</a>, they rely principally on signature whistles to identify each other in the ocean. Dolphins can also copy another dolphin’s whistles as a <a href="https://doi.org/10.1073/pnas.1304459110">way to address each other</a>.</p>
<p>My previous research showed that dolphins have great memory for <a href="https://doi.org/10.1098/rspb.2013.1726">each other’s whistles</a>, but scientists argued that a dolphin might hear a whistle, know it sounds familiar, but <a href="https://doi.org/10.1038/nature.2013.13519">not remember who</a> the whistle belongs to. My colleagues and I wanted to determine if dolphins could associate signature whistles with the specific owner of that whistle. This would address whether or not dolphins remember and hold representations of other dolphins in their minds.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A person standing next to a dolphin holding a vial of urine." src="https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479189/original/file-20220815-19-iv7nt8.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The researchers found that dolphins can identify each other by swimming through and tasting urine, the liquid in the syringe in this photo.</span>
<span class="attribution"><span class="source">Dolphin Quest</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Urine as an identifier</h2>
<p>The first thing my colleagues and I needed to do was find another sense that dolphins use to identify each other. In the 1980s and 1990s, researchers studying spinner dolphins in Hawaii noticed that the dolphins were occasionally <a href="https://www.ucpress.edu/book/9780520082083/the-hawaiian-spinner-dolphin">swimming through each other’s urine</a> and feces with their mouths open. Using these observations as a springboard, my colleagues and I decided to test if dolphins were able to identify each other from urine.</p>
<p>We began by first collecting urine from dolphins under managed care and simply pouring small amounts of it into lagoons where the dolphins live. The dolphins immediately showed interest, and with little training, quickly began to follow the research team anytime we carried poles with cups filled with urine. When we poured urine into the water, the dolphins would open their mouths and swim through the urine plume.</p>
<p>Our team then got urine from dolphins at other facilities to see if the subjects could differentiate between familiar and unfamiliar urine. The dolphins spent more than twice the amount of time with their mouths open tasting familiar urine compared to unfamiliar urine, providing the first evidence that <a href="https://doi.org/10.1126/sciadv.abm7684">dolphins can identify other individuals by taste</a>. </p>
<p>With this, my colleagues and I had what we needed to test representation in signature whistles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A person with a long pole leading a dolphin towards a speaker" src="https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479191/original/file-20220815-11-9s4ix2.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">By pairing urine samples – in the cup at the end of the pole – with the sounds of signature whistles played from an underwater speaker, it was possible to test whether dolphins would recognize if the urine and a whistle were from the same individual.</span>
<span class="attribution"><span class="source">Dolphin Quest</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Pairing urine and whistles</h2>
<p><a href="https://doi.org/10.1016/j.pneurobio.2007.10.005">Previous studies in children</a> have successfully used multiple senses to show that pre-linguistic infants can form conceptual representations of people. My colleagues and I used this type of work as a theoretical basis for our second experiment.</p>
<p>In our experiment, the team first led a dolphin to a speaker before pouring a small amount of urine into the water. After the dolphin tasted the urine, we quickly played the sound of another dolphin’s signature whistle. Sometimes that whistle would be from the same individual as the pee sample. Other times the urine and whistle would not match. The goal was to test if the dolphins react differently if the urine and whistle were from the same dolphin compared with if the urine and whistle were from two different dolphins. If there was a consistent difference in how long the dolphins hovered close to the speaker in the matched or unmatched scenarios, it would indicate the dolphins <a href="https://doi.org/10.1073/pnas.1008169108">knew and recognized when a whistle and urine sample</a> were from the same individual – the same way a person might connect the name of a friend to that friend’s favorite perfume</p>
<p>We found that, on average, when the urine and whistle matched, dolphins spent about 30 seconds investigating the speaker. When there was a mismatch, they <a href="https://doi.org/10.1126/sciadv.abm7684">only stuck around for about 20 seconds</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A person collecting data while a dolphin swims behind him." src="https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479190/original/file-20220815-485-6v7b4b.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">When dolphins were presented with matching urine and whistles, they hovered near the speaker longer than when the samples were not from the same individual.</span>
<span class="attribution"><span class="source">Dolphin Quest</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The fact that the dolphins consistently reacted more strongly to matches than mismatches indicates that they understand which whistles correspond with which urine. This uses the same framework as other studies that use matching sensory information to <a href="https://doi.org/10.1073/pnas.1008169108">demonstrate that animals have mental representations of individuals</a>.</p>
<p>But what makes dolphins different is that they aren’t just matching physical qualities – face with a smell, for example. They are doing this with signature whistles they invent themselves. Just as you can hear a name and imagine a face with all the associated memories, dolphins can hear a signature whistle and match the urine cue. </p>
<h2>Dolphin language?</h2>
<p>This work demonstrates that dolphins have self-created signals that are representational, just as humans have invented names that are representational. Representation opens the possibility that dolphins could theoretically make third-dolphin references – where two dolphins that are communicating refer to a third dolphin that is not in the immediate vicinity. If dolphins can refer to dolphins that aren’t around them presently, this would be similar to the mental time travel a person does when speaking about a friend they haven’t seen in years.</p>
<p>Signature whistles represent the most language-like aspect of dolphin communication currently known. However, the scientific community knows little about <a href="https://doi.org/10.1006/anbe.1998.0881">dolphin non-signature calls</a> or the functions of their <a href="https://www.researchgate.net/publication/255649978_High-Frequency_Burst-Pulse_Sounds_in_AgonisticAggressive_Interactions_in_Bottlenose_Dolphins_Tursiops_truncatus">other acoustic signals</a>. With further research into how dolphins communicate with sound – as well as with chemicals – it may be possible to better understand the minds of these mammals.</p><img src="https://counter.theconversation.com/content/188332/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Bruck 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>Using urine and signature whistles from other dolphins, a team of scientists has shown that dolphins use signature whistles like names and hold mental representations of other dolphins in their minds.Jason Bruck, Assistant Professor of Biology, Stephen F. Austin State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1788052022-03-14T11:20:58Z2022-03-14T11:20:58ZWhale migrations: how new UN treaty aims to protect species on the high seas<figure><img src="https://images.theconversation.com/files/450908/original/file-20220309-2144-7siqi9.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1599%2C1065&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Humpback whales (_Megaptera novaeangliae_) frolicking at the ocean surface.</span> <span class="attribution"><a class="source" href="https://www.naturepl.com/blog/">Tony Wu/WWF</a>, <span class="license">Author provided</span></span></figcaption></figure><p>A humpback whale we tagged while it was feeding off the <a href="https://doi.org/10.1186/s40317-021-00266-8">Western Antarctic Peninsula</a> made a nearly 19,000 km-round trip in 265 days, travelling north from Antarctica to its breeding area off Colombia and back. Whales migrate thousands of kilometres each year, gathering to mate and give birth in the tropics and subtropics during winter and then heading for cooler waters in higher latitudes to feast on abundant prey during summer.</p>
<p><a href="https://doi.org/10.1111/j.1748-7692.1999.tb00887.x">Theories abound</a>, but scientists still can’t agree on why whales undertake these <a href="https://doi.org/10.1111/j.1748-7692.2001.tb01289.x">epic migrations</a>, or even how they manage to navigate <a href="https://doi.org/10.3389/fmars.2020.00414">vast ocean basins</a>.</p>
<p><a href="https://wwfwhales.org/resources/protecting-blue-corridors-report">In a new report</a> from WWF, a global environment charity, scientists compiled the migration tracks of over 1,000 whales worldwide, recorded using satellite tags. For the first time, the global scale and extent of the routes whales traverse during their migrations were illuminated. The report adds to the <a href="https://doi.org/10.1098/rspb.2019.1472">growing understanding</a> among scientists that the routes between critical feeding and breeding habitats are as important to whales as the endpoints themselves.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of the world with whale migration routes highlighted." src="https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=477&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=477&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=477&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=599&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=599&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450907/original/file-20220309-30-1ezimew.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=599&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Migration tracks of over 1,000 whales worldwide, from the WWF Protecting Blue Corridors report.</span>
<span class="attribution"><a class="source" href="https://wwfwhales.org/news-stories/protecting-blue-corridors-report">WWF</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These routes also reveal how <a href="https://doi.org/10.3354/esr01115">perilous</a> the <a href="https://doi.org/10.1126/science.aba4658">ocean</a> is becoming for these giants. Climate change is shifting the places and times that whales can <a href="https://doi.org/10.1111/gcb.15465">reliably find food</a>, while fisheries are discarding nets and ropes that can <a href="https://doi.org/10.3354/meps09923">ensnare and drown whales</a>. Meanwhile around <a href="https://www.ics-shipping.org/shipping-fact/shipping-and-world-trade-driving-prosperity/#:%7E:text=Some%2011%20billion%20tons%20of%20goods%20are%20transported%20by%20ship%20each%20year.">11 billion tons of cargo</a> is moved by sea each year. The routes these ships use cross the <a href="https://doi.org/10.1002/fee.1987">paths</a> of migrating whales and other marine animals which may be struck and killed.</p>
<p>Six out of the 13 largest whale species are either endangered or vulnerable according to the International Union for Conservation of Nature, even after decades of protection following the end of most commercial whaling in <a href="https://iwc.int/whaling">1986</a>.</p>
<p>Marine protected areas created by individual countries are one way to shield whales from some of these threats. These are zones where certain activities, like fishing, are restricted or prohibited. Currently, marine protected areas cover <a href="https://www.protectedplanet.net/en/thematic-areas/marine-protected-areas">less than 8%</a> of the ocean.</p>
<p>But whales move through the waters of multiple countries during their migration and spend much of this time in the high seas, where only <a href="https://www.sciencedirect.com/science/article/pii/S0308597X19309194">1.2%</a> of the ocean is under some form of protection. Clearly, protecting whales requires a global effort.</p>
<h2>Whales beyond borders</h2>
<p>Geopolitical boundaries are invisible to whales but have extraordinary consequences for them. Under the United Nations Convention on <a href="https://www.un.org/depts/los/convention_agreements/convention_overview_convention.htm">the Law of the Sea</a>, countries have rights to fish and pursue other activities in 200-nautical mile exclusive economic zones (EEZ) extending from their coastlines. Countries designating marine protected areas within their EEZs can help <a href="https://doi.org/10.1126/science.aad5443">conserve local ocean habitats</a>.</p>
<p>But since laws vary substantially from country to country, it’s difficult to coordinate efforts to protect whales, although international agreements like the <a href="https://www.cms.int/en/convention-text">Convention on the Conservation of Migratory Species of Wild Animals</a> try to do just this. </p>
<p>It does little good protecting whales in one country, using measures like marine protected areas or rules restricting shipping and fishing, when they may face looser regulation in another country’s EEZ during a single migration. The WWF report showed that 367 humpback whales tracked by satellite in the southern hemisphere together traversed the EEZs of 28 countries during their migrations.</p>
<p>The 64% of the ocean which encompasses the high seas is beyond any EEZ and the authority of any single nation. Whales migrate between habitats thousands of kilometres apart, so it’s unsurprising that many species spend much of their lives there. The 367 tracked humpbacks spent half their time in these areas of the ocean beyond national jurisdictions. </p>
<p>A <a href="https://doi.org/10.1038/s41559-018-0646-8">2018 study</a> tracked 14 large species, from leatherback turtles to white sharks, throughout the Pacific Ocean and revealed that 29% of all the positions recorded by satellite tags were in the high seas. In <a href="https://doi.org/10.1038/s41586-020-2126-y">a 2020 study</a>, we estimated that only 27% of important areas for marine mammals and seabirds in the Southern Ocean were within EEZs.</p>
<figure class="align-center ">
<img alt="Five large open whale mouths surrounded by sea gulls at the ocean surface." src="https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=351&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=351&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=351&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=441&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=441&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451817/original/file-20220314-17-mxfq6x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=441&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some whales congregate in cool, productive waters to feed.</span>
<span class="attribution"><span class="source">Chad Graham/WWF-Canada</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Marine protected areas on the high seas</h2>
<p>International negotiations are underway to figure out how to protect ocean species, including whales, outside of EEZs. In the <a href="https://mpatlas.org/countries/HS">more than 222 million km²</a> that make up the high seas, there are almost no marine protected areas.</p>
<p>United Nations member states agreed in 2017 to <a href="https://www.un.org/bbnj/">negotiate</a> an international treaty for the conservation and sustainable use of marine biodiversity of the high seas. The fourth and final session of these negotiations takes place in New York on March 7-18. The treaty will include ways that marine protected areas could be designated in the high seas, and these areas could restrict activities that threaten whales and other marine species in areas critical for their survival.</p>
<p>The treaty won’t design and implement these marine protected areas, though. That will rely on organisations like the Marine Mammal Protected Areas Task Force, which, with the help of scientists, has located <a href="https://doi.org/10.1017/S0030605321000272">at least 159</a> <a href="https://www.marinemammalhabitat.org/immas/">important marine mammal areas</a> that could become protected. <a href="https://doi.org/10.1016/j.tree.2019.01.009">The migration tracks</a> in the WWF report will be essential when it comes to identifying them.</p>
<p>Marine protected areas are only one measure among several which will be needed to make the high seas safer for marine mammals. Conservationists have to address mounting threats from climate change, fisheries, shipping and pollution. </p>
<p>There are glimmers of hope, however. The <a href="https://doi.org/10.1073/pnas.2121360119">International Maritime Organization</a> and the <a href="https://iwc.int/ship-strikes">International Whaling Commission</a> are collaborating to prevent ships from striking whales. Meanwhile, modifications to fishing equipment and other tools have <a href="https://doi.org/10.3389/fmars.2021.754755">reduced the number</a> of dolphins caught in eastern tropical Pacific yellowfin tuna fisheries by 99%. Critical to any successful conservation effort is a solid foundation of scientific evidence and cooperation on local, regional and international scales.</p><img src="https://counter.theconversation.com/content/178805/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Reisinger receives funding from the WWF, the Antarctic Wildlife Research Fund and the International Whaling Commission. </span></em></p><p class="fine-print"><em><span>Ari Friedlaender has received funding from the WWF, Antarctic Wildlife Research Fund, and the International Whaling Commission. </span></em></p><p class="fine-print"><em><span>Daniel M. Palacios receives funding from the US Navy, WWF, and the International Whaling Commission.</span></em></p>A new report shed light on the migratory routes of 1,000 whales worldwide.Ryan Reisinger, Lecturer in Marine Biology and Ecology, University of SouthamptonAri Friedlaender, Professor of Ocean Sciences, University of California, Santa CruzDaniel M. Palacios, Endowed Associate Professor in Whale Habitats, Oregon State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658042021-12-02T13:42:06Z2021-12-02T13:42:06ZSea otters demonstrate that there is more to muscle than just movement – it can also bring the heat<figure><img src="https://images.theconversation.com/files/432004/original/file-20211115-21-1852gim.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5472%2C3637&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sea otters are born with a supercharged metabolism.
</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cute-sea-otter-making-a-splash-royalty-free-image/1304610196">Adria Photography/Moment via Getty Images</a></span></figcaption></figure><p>Life in the cold can be difficult for animals. As the body chills, organs including the brain and muscles slow down. </p>
<p>The body temperature of animals such as reptiles and amphibians mostly depends on the temperature of their environment – but mammals can increase their metabolism, using more energy to warm their body. This allows them to <a href="https://doi.org/10.1146/annurev.ph.57.030195.000441">live in colder areas and stay active when temperatures drop</a> at night or during winter months. </p>
<p>Although scientists know mammals can increase their metabolism in the cold, it has not been clear which organs or tissues are using this extra energy to generate more heat. Staying warm is especially challenging for small, aquatic mammals like sea otters, so we wanted to know how they have adapted to survive the cold. </p>
<p>We assembled <a href="https://scholar.google.com/citations?hl=en&user=j27jLwUAAAAJ">a</a> <a href="https://scholar.google.com/citations?hl=en&user=oWs13ikAAAAJ">research</a> <a href="https://scholar.google.com/citations?hl=en&user=-BQkMmoAAAAJ">team</a> with expertise in both human and marine mammal metabolism, including <a href="https://scholar.google.com/citations?hl=en&user=hsiWIEEAAAAJ">Heidi Pearson</a> of the University of Alaska Southeast and <a href="https://scholar.google.com/citations?hl=en&user=G3AiPisAAAAJ">Mike Murray</a> of the Monterey Bay Aquarium. Understanding energy use in animals adapted to life in the cold may also provide clues for manipulating human metabolism.</p>
<h2>Sea otter metabolism</h2>
<p>It is especially difficult for water-living mammals to stay warm because <a href="https://doi.org/10.1080/23328940.2021.1988817">water conducts heat away from the body much faster than air</a>. Most marine mammals have large bodies and a thick layer of fat or <a href="https://doi.org/10.1080/23328940.2021.1988817">blubber for insulation</a>. </p>
<p>Sea otters are the smallest of the marine mammals, and do not have this thick layer of blubber. Instead, they are insulated by the densest fur of any mammal, with as many as <a href="https://doi.org/10.1111/j.1748-7692.1992.tb00120.x">a million hairs per square inch</a>. This fur, however, is high maintenance, requiring <a href="https://www.youtube.com/watch?v=sgFMVRtkpVY&list=PLq_DVMr7CmlIb0n3DhtcU8lESsxX-wqP7&index=2">regular grooming</a>. About 10% of a sea otter’s <a href="https://doi.org/10.1242/jeb.02767">daily activity</a> involves maintaining the insulating layer of air trapped in their fur.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Z4OKk2lErwc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Grooming is a never-ending job.</span></figcaption>
</figure>
<p>Dense fur is not enough, by itself, to keep sea otters warm. To generate enough body heat, their metabolic rate at rest is <a href="https://link.springer.com/book/10.1007%2F978-3-319-98280-9">about three times higher</a> than that of most mammals of similar size. This high metabolic rate has a cost, though.</p>
<p>To obtain enough energy to fuel the high demand, sea otters must eat <a href="https://doi.org/10.1086/physzool.55.1.30158441">more than 20% of their body mass</a> in food each day. In comparison, humans eat around 2% of their body mass – about <a href="https://doi.org/10.1079/BJN19810074">3 pounds (1.3 kilograms) of food per day</a> for a 155-pound (70 kg) person.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sea otter floating on its back eating a crab." src="https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432007/original/file-20211115-17-rlq9ul.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">Feeding on Dungeness crab in Monterey Bay, California.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/sea-otter-and-crab-royalty-free-image/1209955271">Chase Dekker Wild-Life Images/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Where does the heat come from?</h2>
<p>When animals eat, the energy in their food cannot be used directly by cells to do work. Instead, the food is broken down into simple nutrients, such as fats and sugars. These nutrients are then transported in the blood and absorbed by cells. </p>
<p>Within the cell are compartments called mitochondria where nutrients are converted into <a href="https://www.nature.com/scitable/definition/atp-318/">ATP</a> – a high-energy molecule that acts as the energy currency of the cell. </p>
<p>The process of converting nutrients into ATP is similar to <a href="https://www.usgs.gov/special-topic/water-science-school/science/hydroelectric-power-how-it-works?qt-science_center_objects=0#qt-science_center_objects">how a dam turns stored water into electricity</a>. As water flows out from the dam, it makes electricity by spinning blades connected to a generator – similar to wind turning the blades on a windmill. If the dam is leaky, some water – or stored energy – is lost and cannot be used to make electricity.</p>
<p>Similarly, leaky mitochondria are less efficient at making ATP from nutrients. Although the leaked energy in the mitochondria cannot be used to do work, it generates heat to warm the sea otter’s body.</p>
<p><a href="https://doi.org/10.1152/physrev.1997.77.3.731">All tissues in the body use energy and make heat</a>, but some tissues are larger and more active than others. Muscle makes up 30% of the body mass of most mammals. When active, muscles consume a lot of energy and produce a lot of heat. You have undoubtedly experienced this, whether getting hot during exercise or <a href="https://theconversation.com/its-cold-a-physiologist-explains-how-to-keep-your-body-feeling-warm-108816">shivering when cold</a>. </p>
<p>To find out if muscle metabolism helps keep sea otters warm, we studied small muscle samples from sea otters ranging in size and age from newborn pups to adults. We placed the muscle samples in small chambers designed to monitor oxygen consumption – a measure of how much energy is used. By adding different solutions that stimulated or inhibited various metabolic processes, we determined how much energy the mitochondria could use to make ATP – and how much energy could go into heat-producing leak. </p>
<p>We discovered the mitochondria in <a href="https://doi.org/10.1126/science.abf4557">sea otter muscles could be very leaky</a>, allowing otters to turn up the heat in their muscles without physical activity or shivering. It turns out that sea otter muscle is good at being inefficient. The energy “lost” as heat while turning nutrients into movement allows them to survive the cold.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sea otter floats on her back, feeding her pup small bits of food." src="https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/431999/original/file-20211115-17-1g2znp7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&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 mother sea otter ‘hand-feeds’ her baby bits of crab. Moro Bay, California.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/feeding-baby-dinner-royalty-free-image/582228357">PhotoviewPlus/Moment Open via Getty Images</a></span>
</figcaption>
</figure>
<p>Remarkably, we found newborn pups have the same metabolic ability as adults, even though their muscles have not yet matured for swimming and diving. </p>
<h2>Broader implications</h2>
<p>Our research clearly demonstrates that muscle is important for more than just movement. Because muscle makes up such a large portion of body mass, even a small increase in muscle metabolism can dramatically increase how much energy an animal uses. </p>
<p>[<em>More than 140,000 readers get one of The Conversation’s informative newsletters.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140K">Join the list today</a>.]</p>
<p>This has important implications for human health. If scientists discover ways to safely and reversibly increase skeletal muscle metabolism at rest, doctors could possibly use this as a tool to reduce climbing rates of obesity by increasing the amount of calories a patient can burn. Conversely, reducing skeletal muscle metabolism could conserve energy in patients suffering from cancer or other wasting diseases and could reduce food and resources needed to support astronauts on long-duration spaceflight.</p><img src="https://counter.theconversation.com/content/165804/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Randall Davis has received research funding from the National Science Foundation and NOAA.</span></em></p><p class="fine-print"><em><span>Melinda Sheffield-Moore and Traver Wright do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research finds that ‘leaky mitochondria’ help keep sea otters warm.Traver Wright, Research Assistant Professor of Health and Kinesiology, Texas A&M UniversityMelinda Sheffield-Moore, Professor of Health and Kinesiology, Texas A&M UniversityRandall Davis, Regents Professor, Department of Marine Biology, Texas A&M UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1724712021-11-25T14:23:53Z2021-11-25T14:23:53ZSea lion whiskers can move like human fingertips: here’s how we found out<figure><img src="https://images.theconversation.com/files/433958/original/file-20211125-23-kvrn9v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/big-sea-lion-swimming-in-blue-water-5967965/">Lachlan Ross / pexels </a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Humans have amazing fingertips. They are sensitive and can be moved over objects to feel its softness, texture, size and shape. These movements are both complex, and “task-specific”. This means that you adopt different movements depending on what you want to feel about an object. We squeeze or push objects to judge softness, and feel around the edges of objects to judge size and shape. And if you wanted to feel the texture of an object, you would sweep your fingertips over the surface. </p>
<p>Being able to adopt <a href="https://scholarship.claremont.edu/cmc_fac_pub/407/">different movement strategies</a> shows that we can precisely control our fingertip movements and draw on our past experiences in order to pay attention to important aspects of an object – the edges of shapes and the surfaces of textures, for example. This means that we have a high level of control over our sensory perception, and we call this active touch sensing.</p>
<h2>Touch sensing in mammals</h2>
<p>Most mammals do not have as moveable or sensitive fingertips as humans. Instead they have whiskers, which are touch sensitive hairs on their faces, and used to guide locomotion, foraging for food and to explore objects.</p>
<p>Neuroscientists have been <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mam.12253">studying whiskers</a> for decades, especially in laboratory rats and mice, trying to understand how signals from the whiskers are processed in the brain. But only now are we realising that whiskers are also moved with amazing strategies, just like our fingers.</p>
<p>Rats, mice, and some other mammals, can move their whiskers in a to-and-fro scanning motion called “whisking”. Whisking is one of the fastest movements that mammals can make, occurring up to 25 times per second in mice.</p>
<p>When rats and mice contact objects they also adopt <a href="https://journals.physiology.org/doi/full/10.1152/jn.90783.2008">other whisker movements</a>. These include bunching up their whiskers to make more of them touch a surface, making light touches to enable clearer signals against a surface, and slowing down whisker movements so they contact the surface for longer.</p>
<p>But no one knew whether animals could adapt their whisker movements specifically for different tasks.</p>
<p>Such “task-specific” movements would be an exciting discovery as it would indicate a precise level of control over their sensors and perception. </p>
<h2>Choosing a candidate species</h2>
<p>The first step in answering this important question was to choose a likely candidate species for our investigation.</p>
<p>Pinnipeds, including seals, sea lions and walruses, have whiskers that are particularly <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jmor.21246">thick</a> and long, making them easier to measure than those of smaller mammals such as mice. </p>
<p>They also have some of the most sensitive whiskers of any mammal – they can detect textures and shapes to the same sensitivity as human fingertips, <a href="https://journals.biologists.com/jeb/article/201/22/3023/7912/Ambient-temperature-does-not-affect-the-tactile">even in cold water</a> when our fingers would go numb.</p>
<p>They are also moveable. We have previously found that California sea lions make the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192888/">largest and most controlled</a> movements with their whiskers, when compared to harbour seals and Pacific walruses.</p>
<p>Those factors, plus their ability to perform object-discrimination tasks – where they could distinguish between objects based on <a href="https://link.springer.com/article/10.3758/BF03199008">size and shape</a> – made California sea lions the ideal subject for our investigation on task-specific whisker movements.</p>
<h2>Our work with Lo</h2>
<p>For our <a href="https://journals.biologists.com/jeb/article/224/21/jeb243085/273347/California-sea-lions-employ-task-specific">study</a>
we used a sea lion, Lo, for the full complement of experiments. Having only one individual is common in marine mammal studies, but it does put pressure on the investigators to collect good quality and highly quantitative data from that one individual.</p>
<p>Lo was trained to complete a texture-discrimination task using only her whiskers. </p>
<p>She had to find a medium-textured, fish-shaped object among other distractor fish. She also completed a size-discrimination task of finding a medium-sized fish amongst other distractors, and a visual task of finding a grey fish amongst other coloured distractors (sea lions use very small whisker movements in visual tasks).</p>
<p>Lo was filmed doing the tasks thousands of times, and her whisker and head positions were tracked in the video footage.</p>
<p>Looking at the data and the video footage it was clear that Lo made task-specific movements with her whiskers. She made sweeping movements over textured surfaces, and felt around the edges of the different sized shapes. These specific movement strategies are also used by humans with our fingertips.</p>
<figure>
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<figcaption><span class="caption">The sea lion, Lo, participating in different tasks for this study.</span></figcaption>
</figure>
<p>The ability to switch whisker exploration strategies between tactile tasks enabled Lo to complete the tasks efficiently. Lo found the correct fish in almost all trials and made decisions quickly, in under half a second. Video footage of the other sea lions also showed them employing the same strategies, so we think that this might be common among California sea lions in general.</p>
<h2>And now other animals</h2>
<p>Seeing the same movement strategies conserved from sea lion whisker movements to human fingertip movements showcases how important these strategies are for improving touch signals across different tasks. </p>
<p>It is likely that other species of Pinniped will be able to make task-specific whisker movements, since they also have sensitive, moveable whiskers. We are <a href="https://www.mmu.ac.uk/research/research-centres/ecology-environment/projects/touch-sensing-mammals">investigating</a> this now, along with other species of carnivores, such as otters. </p>
<p>This is the first time that task-specific whisker touch sensing has been documented. It demonstrates that studying whiskers can give us important insights into animal movement control, as well as their perception and cognition.</p>
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<strong>
Read more:
<a href="https://theconversation.com/how-we-found-a-special-maths-equation-hidden-in-rat-whiskers-130345">How we found a special maths equation hidden in rat whiskers</a>
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<img src="https://counter.theconversation.com/content/172471/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robyn Grant receives funding from the Royal Society. </span></em></p>Lo, a California sea lion, was able to control what she perceives using her whiskers — a highly cognitive skill.Robyn Grant, Senior Lecturer in Comparative Physiology & Behaviour, Manchester Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1600902021-05-06T20:07:19Z2021-05-06T20:07:19ZSwim like a sea lion, splash like a seal: how evolution engineered nature’s underwater acrobats<figure><img src="https://images.theconversation.com/files/399121/original/file-20210506-14-1jtotg0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2348%2C1644&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Few fish can outswim a seal. Seals fly through the waves, predators in their natural element. But, unlike fish, seals are air-breathing mammals whose ancestors only returned to the water from a life on land some 30 million years ago. </p>
<p>On entering the water, seals had to adapt both their bodies and behaviour to become efficient underwater swimmers. Like penguins and sea turtles, they use streamlined limbs to propel themselves through the water.</p>
<p>Yet, there is a mystery here. Even though all seals and sea lions are descended from a common ancestor, they use two radically different modes of propulsion: true seals (phocids) swim with their feet; fur seals and sea lions (otariids) rely on their wing-like forelimbs. </p>
<p>How did these two related groups come up with such different swimming styles? Did they start from a common base, but then adapt to different circumstances? Or do we have it all wrong, and phocids and otariids have different ancestors after all? </p>
<figure>
<iframe src="https://player.vimeo.com/video/543009382" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Seals and sea lions share a common suite of behaviours that they use to propel themselves through the water.</span></figcaption>
</figure>
<p>To find out, we partnered with a <a href="https://www.monash.edu/research/infrastructure/platforms-pages/wind-tunnel">team of engineers</a> to combine cutting-edge computer simulations with anatomical and live animal observations. This multi-angled study, <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(21)00358-4">published today in Current Biology</a>, allowed us to determine how, and how effectively, seals use their forelimbs during swimming.</p>
<h2>Engineering a seal</h2>
<p>Evolutionary biology and engineering might seem like strange bedfellows. Yet, ever since Leonardo Da Vinci, humans have sought to understand and adapt nature’s “designs”, giving rise to a field of engineering known today as <a href="https://en.wikipedia.org/wiki/Biomimetics">biomimetics</a>. </p>
<p>Engineering allows biologists to look beyond the mere shape of an animal, and instead ask how that shape is adapted to function within the physical limits set by its environment.</p>
<p>Applying this approach our question, we initially created 3D computer models of forelimb flippers representing each of the main seal families: from the bear-like paws of phocids (such as grey seals) to the wing-like flippers of fur seals and sea lions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=612&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=612&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=612&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=769&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=769&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397992/original/file-20210430-13-aiukz2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=769&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">How streamlined are seal flippers? Northern seals like grey seals have bear-like paws with large claws, while fur seals and sea lions have very streamlined flippers. Interestingly, Antarctic leopard seals have independently evolved streamlined flippers despite being members of the foot-propelled seal family.</span>
<span class="attribution"><span class="source">Photos by Ben Burville, David Hocking and Robert Harcourt.</span></span>
</figcaption>
</figure>
<p>Next, we used computer-simulated fluid dynamics to model how water flows around the different flipper shapes. Perhaps unsurprisingly, we found the wing-like flippers of fur seals and sea lions produce little drag and considerable lift. The opposite is true of the clawed paws of true seals, which consequently make fairly poor tools for swimming. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397993/original/file-20210430-19-168ubzx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Computer fluid dynamics simulations showing how water flows around seal flippers. Note how the large claws on a grey seal interrupt the flow, while leopard and fur seals have very smooth water flow around their streamlined front flippers.</span>
<span class="attribution"><span class="source">David Hocking</span></span>
</figcaption>
</figure>
<h2>Repeated evolution of forelimb flippers</h2>
<p>So far, our results seem to confirm the fundamental difference between phocids and otariids. But there’s a twist to the story: streamlined fore-flippers are not unique to otariids. </p>
<p>Our results show that some rear-propelled Antarctic true seals independently evolved streamlined fore-flippers as well. This is taken to the extreme in leopard seals, whose flippers are almost indistinguishable from those of otariids. Out at sea, their massive forelimbs likely give them the speed and agility needed to pursue evasive prey such as penguins. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=594&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=594&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=594&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=747&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=747&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399118/original/file-20210506-21-m8dzrp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=747&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Antarctic leopard seals have broad wing-like flippers that help them to pursue highly evasive prey like penguins.</span>
<span class="attribution"><span class="source">Fiona Anderson</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/scientists-thought-these-seals-evolved-in-the-north-3-million-year-old-fossils-from-new-zealand-suggest-otherwise-149746">Scientists thought these seals evolved in the north. 3-million-year-old fossils from New Zealand suggest otherwise</a>
</strong>
</em>
</p>
<hr>
<p>The independent appearance of flippers within southern true seals provides a clue to how forelimb swimming may have evolved in the first place. </p>
<p>Early seals probably swam with their feet and, like their terrestrial ancestors and <a href="https://theconversation.com/sharp-claws-helped-ancient-seals-conquer-the-oceans-92828">northern true seals today</a>, used their clawed forepaws to catch and eat large prey. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=704&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=704&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=704&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=884&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=884&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397995/original/file-20210430-22-1mibl02.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=884&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Northern seals like grey seals can use their clawed paws for a range of tasks including grooming and holding prey. In contrast, species with wing-like flippers aren’t able to use their limbs in this way, with large prey instead needing to be shaken apart using flexible necks.</span>
<span class="attribution"><span class="source">David Hocking</span></span>
</figcaption>
</figure>
<p>Over time, otariids and southern true seals independently began to chase faster, more agile prey. This would have required their forelimbs to assume a more active role during swimming, which manifested itself in greater streamlining, reduced claws and — in otariids — a complete switch from foot to flipper-based propulsion.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sharp-claws-helped-ancient-seals-conquer-the-oceans-92828">Sharp claws helped ancient seals conquer the oceans</a>
</strong>
</em>
</p>
<hr>
<p>So there you have it: perhaps seals use different swimming styles not because of separate evolutionary origins, but because they adapted to different environments. And it seems they did so more than once! </p>
<p>This theory makes a lot of sense in light of how seals behave and look today. Its litmus test likely lies elsewhere, however: buried beneath rocks, rather than frolicking beneath the waves. Only fossils can tell us what early seals were really like and, if our idea is correct, we should ultimately find some that match it. Only time will tell.</p><img src="https://counter.theconversation.com/content/160090/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Hocking receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Alistair Evans receives funding from the Australian Research Council and Monash University, and is an Honorary Research Affiliate with Museums Victoria.</span></em></p><p class="fine-print"><em><span>Hazel L. Richards receives an Australian government RTP scholarship. </span></em></p><p class="fine-print"><em><span>Felix Georg Marx and Shibo Wang 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>New research combines cutting-edge engineering with animal behaviour to explain the origins of efficient swimming in nature’s underwater acrobats: seals and sea lions.David Hocking, Curator of Vertebrate Zoology and Palaeontology, Monash UniversityAlistair Evans, Associate Professor, Monash UniversityFelix Georg Marx, Curator Vertebrates, Te Papa TongarewaHazel L. Richards, PhD candidate, Monash UniversityShibo Wang, Postdoctoral research fellow, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1568242021-03-17T18:01:44Z2021-03-17T18:01:44ZRisk versus reward on the high seas – skinny elephant seals trade safety for sustenance<figure><img src="https://images.theconversation.com/files/389965/original/file-20210316-15-139gw3g.jpg?ixlib=rb-1.1.0&rect=370%2C531%2C7872%2C4956&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Female elephant seals take seven-month feeding trips during which they balance danger, starvation and exhaustion.</span> <span class="attribution"><a class="source" href="https://costa.eeb.ucsc.edu/">Dan Costa</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Every year, northern elephant seals set off on a <a href="https://doi.org/10.1371/journal.pone.0036728">seven-month, 6,000-mile (10,000-kilometer) journey</a> across the North Pacific ocean in search of fish and squid to eat. They start the journey after sitting on the beach for a couple months – <a href="https://doi.org/10.1073/pnas.1506520112">replacing their fur</a> and losing fat – and gradually gain weight over the course of the foraging trip. On these excursions, elephant seals don’t just swim on the surface – they <a href="https://doi.org/10.1139/z88-064">dive continuously</a>, day and night.</p>
<p>To rest, they <a href="https://doi.org/10.1139/z97-004">swim down hundreds of meters below the ocean surface</a> then slowly roll onto their backs and drift back and forth like <a href="https://doi.org/10.1098/rsbl.2009.0719">falling leaves</a>. These dives last around 25 minutes and are called drift dives. The resting period of drift dives is the most dangerous time for an elephant seal: Waking up in the jaws of a <a href="https://doi.org/10.1038/s41598-019-39356-2">white shark or killer whale</a> is not a good way to start the day.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A seal floating asleep." src="https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388667/original/file-20210309-15-lz227g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Elephant seals rest underwater where they float upward or sink slowly down depending on whether they are fat or skinny.</span>
<span class="attribution"><span class="source">Danielle Dube through an Art-Science Residency with the UC Santa Cruz Norris Center for Natural History</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We are two biologists studying <a href="https://scholar.google.com/citations?user=ET7UYVoAAAAJ&hl=en&oi=ao">diving behavior</a> and <a href="https://scholar.google.com/citations?user=mSTFM0EAAAAJ&hl=en&oi=ao">sleep</a> in <a href="https://www.jessiekb.com/">marine mammals</a>. Specifically, we are fascinated by the decisions that elephant seals make as they roam the open ocean and navigate extreme changes in their <a href="https://doi.org/10.1111/ele.12871">environment</a> and <a href="https://doi.org/10.1098/rsbl.2017.0722">their own bodies</a>. The open ocean is a dangerous place, and animals have to continuously weigh the risks of predation, starvation and exhaustion. Choosing when to rest and when to feed has serious consequences. </p>
<p>Elephant seals have two options: rest during the safety of the dark night and feed during the day when food is harder to come by, or rest during the day when there is a much higher chance of <a href="https://doi.org/10.1038/s41598-019-39356-2">being eaten by a predator</a> and feed during the night when fish and squid are more available.</p>
<p>So we wondered, do skinny, hungry seals take more risks than plump, healthy seals? Our newest study, just published in the journal <a href="https://advances.sciencemag.org/content/7/12/eabd9818">Science Advances</a>, reveals that elephant seals fine-tuned their risk–taking behavior throughout the foraging trip.</p>
<iframe src="https://www.google.com/maps/d/u/0/embed?mid=1EOJAEebLBVvCynmmwTPDRTi5qVY_fyUa" width="100%" height="480" caption="Map of elephant seal foraging routes."></iframe>
<figure><figcaption><span class="caption">This interactive map shows foraging routes for individual seals used in the study. Zoom in and click on a route to learn more about that seal’s journey and habits.</span></figcaption></figure>
<h2>Risk vs. reward</h2>
<p>One simple question is fundamental to ecologists’ understanding of the natural world: Do hungry animals take more risks to find food? This should be <a href="http://dx.doi.org/10.1098/rspb.2018.0180">true in theory</a>, because wild animals perpetually weigh the <a href="https://doi.org/10.1098/rstb.2010.0207">risks of starvation and predation</a>. For most species, it is nearly impossible to <a href="https://doi.org/10.1038/s41598-019-46487-z">measure continuous changes in health</a>. As a result, many theories about risk and reward in the animal kingdom have been around for decades but have yet to be tested. </p>
<p>The ocean is a fascinating place to study risk and reward, because light levels determine life and death in three dimensions: The surface of the ocean is bright, and predators can hunt much more easily; but the <a href="https://oceanservice.noaa.gov/facts/light_travel.html#:%7E:text=Sunlight%20entering%20the%20water%20may,on%20depth%20and%20light%20level">light quickly fades</a> as you dive deeper into the ocean. For elephant seals, light levels are directly related to risk, because their main predators <a href="https://doi.org/10.1023/A:1007520931105">inhabit shallow waters</a> and <a href="https://www.jstor.org/stable/29775147?casa_token=c3uShnPqeLsAAAAA%3ArGI-v02t04zdz0mbAYJC5sPIa0EwivRk4eUt4qiV1HJc29nZHRInPnpKKEvzZG_WYxAj54hU3QeLrJmm0l9AYIYqRYIHajzETL1RjRkruyQn74BUfMRu&seq=1#metadata_info_tab_contents">use light to hunt</a>. For elephant seals, resting is safer at night when predators can’t find them. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Seals over a gradient of light levels during day and night" src="https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/389479/original/file-20210315-13-1unh0zg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sleeping seals face the highest risk during the daytime and in shallow water, whereas risk is lowest during the nighttime and in deep water.</span>
<span class="attribution"><span class="source">Illustrations by Danielle Dube, Infographic by Jessica Kendall-Bar</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Light levels are also directly related to reward, because most elephant seal prey – <a href="https://doi.org/10.3389/fmars.2018.00430">fish and squid</a> – migrates <a href="https://www.cell.com/current-biology/pdf/S0960-9822(14)01067-7.pdf">up and down in the water column each day</a>. During the day, when light levels are high, fish and squid remain in the depths to avoid predators. However, at night, when light levels are low, fish and squid swim up closer to the surface to feed on phytoplankton. For seals, foraging is <a href="https://doi.org/10.2307/4616">more efficient at night</a>, when prey have emerged from the depths to find their own food. </p>
<p>This means the best time to eat is also the safest time to rest, and seals must pick one behavior over the other. Do they prioritize resting safely or feeding efficiently? And does this change over time as they gain fat?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A female elephant seal swimming in the ocean with small tags on her head and back." src="https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388631/original/file-20210309-15-25zwme.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">A female elephant seal carries a satellite tag (on her head) and time-depth recorder (on her back).</span>
<span class="attribution"><span class="source">Dan Costa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Drift dives provide the answers</h2>
<p>Thanks to a long-term monitoring program led by our colleague <a href="https://www.youtube.com/watch?v=4IbSp9Ha_zs">Dan Costa</a>, our team had access to dive data from 71 adult female elephant seals <a href="https://www.youtube.com/watch?v=rMvfJGo0Coo">tagged with small devices</a> that record time, depth, light, latitude and longitude every four seconds.</p>
<p>Interestingly – and central to this research – when seals perform drift dives, <a href="https://doi.org/10.1111/j.1365-2656.2010.01735.x">fat seals float upward while skinny seals sink down</a>. This means we can use drifting rates from our dive data to <a href="https://doi.org/10.1093/beheco/ary183">calculate the seals’ percentage of body fat</a> through time. Using data on light, depth and time, we can also approximate risk level. In other words, we know if seals are fat or skinny, and we know how much risk they are taking. Even better, we know both of these metrics continuously over the entire course of their foraging trips.</p>
<p>By simultaneously measuring body fat and risk-taking through time, we learned that elephant seals <a href="https://advances.sciencemag.org/content/7/12/eabd9818">took more risks when they were skinnier and prioritized safety when they were fatter</a>. Early in the foraging trip, when seals on average had a slim 22% body fat, they rested just after sunrise – 80% of their rest dives occurred during the high-risk daytime. This allowed them to do most of their foraging at night, when food is easier to find. </p>
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<p>Later in the foraging trip, when seals had plumped up to 35% body fat, they rested just before sunrise. Only 30% of their rest dives occurred during the high-risk daytime. Gradual shifts in body condition and behavior over the 220-day foraging trip accumulated to an impressive <a href="https://www.jessiekb.com/lightscapes-of-fear">six–hour shift in average rest time</a> by the end of the trip.</p>
<p>We also discovered that fatter seals rested 300 feet (100 meters) deeper in the water – where it is also 300 times darker – than where thinner seals rested. This further supports the idea that seals are strategically modifying their exposure to light levels – using both rest schedule (time) and rest depth (space) – to minimize risk. We call this the <a href="https://advances.sciencemag.org/content/7/12/eabd9818">lightscape of fear</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/x3ugpT1ej0M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Animation by Jessica Kendall-Bar, with illustrations by Danielle Dube through an Art-Science Residency with the UC Santa Cruz Norris Center for Natural History.</span></figcaption>
</figure>
<h2>Lessons from seals at sea</h2>
<p>Our study provides a window into the real-time decision-making of an elephant seal in the open ocean as it weighs consequences of a nap below the ocean surface. Although light has previously been identified as a <a href="https://doi.org/10.1126/science.aar7121">critical environmental constraint</a>, no study has continuously monitored an animal’s use of the lightscape relative to extreme shifts in its fat stores and health.</p>
<p>By tracking these metrics together, we were able to better understand the behavior of a wild animal trying to find food while trying to avoid becoming food. Using elephant seals as a model, we can begin to understand how these rules apply to other species – from birds to bats to bears – and scale up to influence entire ecosystems.</p><img src="https://counter.theconversation.com/content/156824/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roxanne Beltran receives funding from the National Science Foundation and National Geographic.</span></em></p><p class="fine-print"><em><span>Jessica Kendall-Bar receives funding from the National Science Foundation and the Office of Naval Research. </span></em></p>By measuring how and when elephant seals sleep, researchers were able to figure out how elephant seals change their risk-taking behavior as they gain weight.Roxanne Beltran, Assistant Professor of Ecology and Evolutionary Biology, University of California, Santa CruzJessica Kendall-Bar, PhD Candidate in Ecology and Evolutionary Biology, University of California, Santa CruzLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1497462020-11-11T01:06:08Z2020-11-11T01:06:08ZScientists thought these seals evolved in the north. 3-million-year-old fossils from New Zealand suggest otherwise<p>A fossil discovery in New Zealand has revealed a new species of monk seal that once called Australasia home. We introduce the three million-year-old seal, <em>Eomonachus belegaerensis</em>, in a paper published today in the <a href="http://dx.doi.org/10.1098/rspb.2020.2318">Proceedings of the Royal Society B</a>. </p>
<p><em>Eomonachus</em> is the first monk seal species, living or extinct, ever found in the southern hemisphere — and the oldest found anywhere. </p>
<p>It’s rewriting everything experts thought they knew about the evolution of “monachines”, a group of seal relatives comprising the two living species of monk seal, the elephant seals, as well as certain species of Antarctic seals.</p>
<h2>On the brink of vanishing</h2>
<p>Monk seals are some of the world’s rarest and most endangered marine mammals. There are fewer than 2,100 <a href="https://www.mmc.gov/priority-topics/species-of-concern/mediterranean-monk-seal/">Mediterranean</a> and <a href="https://www.staradvertiser.com/2020/03/27/breaking-news/noaa-hawaiian-monk-seal-population-remained-steady-at-just-above-1400-in-2019/">Hawaiian</a> monk seals alive today. The Caribbean monk seal was <a href="https://www.sciencedaily.com/releases/2008/06/080608074828.htm">hunted to extinction</a> by the 1950s.</p>
<p>Conservationists are now scrambling to save what’s left of Earth’s last exclusively tropical seals from disappearing.</p>
<figure class="align-center ">
<img alt="A Hawaiian monk seal, and its pup, on a beach." src="https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=377&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=377&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=377&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=474&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=474&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368246/original/file-20201109-18-qvoamc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=474&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Hawaiian monk seal emerges from the surf. This is an endangered species of earless seal (Phocidae family) that’s endemic to the Hawaiian Islands.</span>
<span class="attribution"><span class="source">Robert Harcourt (Macquarie University)</span></span>
</figcaption>
</figure>
<p>That said, we would be wrong to assume monk seals were doing just fine before humans began exploiting them. How they fared over the past few million years remains unclear. We also don’t know where they originated, as fossils are few and far between.</p>
<p>Scientists traditionally thought all monk seals evolved in the North Atlantic Ocean. Before the discovery of <em>Eomonachus</em>, monk seals had only been found in the Northern Hemisphere. </p>
<p>In fact, most monachine fossils are found in the north, even though several living monachines (Antarctic seals and elephant seals) live <a href="https://www.publish.csiro.au/am/am11036">almost exclusively</a> in the Southern Ocean.</p>
<p>The unexpected discovery of <em>Eomonachus</em> has completely flipped the evolutionary history not only of monk seals, but of all monachines — by placing all three in the Southern Hemisphere for the first time. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/marine-species-are-more-threatened-than-we-thought-and-weve-only-looked-at-3-36914">Marine species are more threatened than we thought – and we've only looked at 3%</a>
</strong>
</em>
</p>
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<h2>A monk seal from New Zealand</h2>
<p>The recovery of the first known <em>Eomonachus</em> fossils came in the form of seven skulls uncovered along the coast of Taranaki, on New Zealand’s North Island. The fossils were retrieved by local collectors and donated to the <a href="https://www.tepapa.govt.nz/">Te Papa Tongarewa</a> and <a href="https://www.canterburymuseum.com/">Canterbury</a> museums. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=313&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=313&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=313&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=394&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=394&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368486/original/file-20201110-22-zc7lxt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=394&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The seven fossilised skulls of the extinct monk seal species <em>Eomonachus</em>.</span>
<span class="attribution"><span class="source">Erich Fitzgerald (Museums Victoria)</span></span>
</figcaption>
</figure>
<p>Our team eventually named the species <em>Eomonachus belegaerensis</em>. This translates to “dawn monk seal from Belegaer”. Belegaer is the fictional sea that lies west of “Middle Earth”, the land from J. R. R. Tolkein’s Lord of The Rings trilogy which is often associated with New Zealand.</p>
<p>But what were monk seals doing in New Zealand three million years ago? </p>
<p>Well, in the past, southern oceans were a lot warmer than they are today. And ancient monk seals, much like their modern relatives, lived in subtropical waters. </p>
<p>But until <a href="https://theconversation.com/in-a-land-of-ancient-giants-these-small-oddball-seals-once-called-australia-home-144574">this year</a>, few scientific studies on extinct monachines had been conducted in the southern hemisphere. This is likely why <em>Eomonachus</em> eluded scientists for so long.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/in-a-land-of-ancient-giants-these-small-oddball-seals-once-called-australia-home-144574">In a land of ancient giants, these small oddball seals once called Australia home</a>
</strong>
</em>
</p>
<hr>
<h2>The evolution of monachines</h2>
<p>Following the unveiling of <em>Eomonachus</em>, we decided to re-investigate the evolution of the monachines. </p>
<p>Our research indicates this group of seals evolved in the Southern Hemisphere after all. This is in contrast with every theory previously put forward by scientists.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A picture of James Rule holding one of the monk seal fossils." src="https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368243/original/file-20201109-21-c1qo1p.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">Monash University palaeontologist James Rule with one of the <em>Eomonachus</em> skull fossils found in New Zealand.</span>
<span class="attribution"><span class="source">Erich Fitzgerald/Museums Victoria</span></span>
</figcaption>
</figure>
<p>If there is indeed a southern origin for monachines, this would mean the group crossed the equator at least eight times throughout its evolutionary history.</p>
<p>However, the warm waters at the equator are widely accepted to be a thermal barrier which is difficult for <a href="https://theconversation.com/northern-exposure-fossils-of-a-southern-whale-found-for-the-first-time-in-the-north-85254">marine mammals to cross</a>. </p>
<p>If past monachines did jump between both hemispheres, they would have had broad environmental tolerances that let them do this. And this would have enabled their dispersal around the world. </p>
<p>It’s difficult to say conclusively whether modern seals share this trait, but we do know it’s rare for them to cross the equator during their lifetime.</p>
<h2>Climate change and seal extinction</h2>
<p>So why aren’t monk seals living around New Zealand now?</p>
<p>About 2.5 million years ago, marine megafauna experienced an <a href="https://www.popsci.com/marine-megafauna-mass-extinction/">extinction event</a>, thought to have been caused by a drop in sea levels as a result of falling global temperature.</p>
<p>Previous research has theorised this change in climate spurred the extinction of many <a href="https://lens.monash.edu/@science/2020/04/04/1379872/rare-fossil-tooth-discovery-reveals-extinct-group-of-seals">ancient seals</a> in the Southern Hemisphere. This would have included <em>Eomonachus</em>, as well as other extinct monachines.</p>
<p>This suggests the world’s last two species of monk seal, vestiges of what was once likely a widespread group, are also at risk from climate change. </p>
<p>If sea levels continue to rise, the beaches monk <a href="https://theconversation.com/unlocking-the-mystery-of-how-true-seals-disappeared-from-the-cape-44344">seals rely on</a> for resting and breeding may disappear. Rising temperatures could also <a href="https://theconversation.com/climate-change-could-drive-coastal-food-webs-to-collapse-76798">disrupt food webs</a>, making it difficult for them to find food. </p>
<p>While the discovery of <em>Eomonachus</em> is exciting, it can also be considered a cautionary tale.</p><img src="https://counter.theconversation.com/content/149746/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Patrick Rule receives funding from an Australian Government Research Training Program Scholarship, and the Robert Blackwood Scholarship. </span></em></p><p class="fine-print"><em><span>Felix Georg Marx received funding from Australian Research Council DECRA fellowship (DE190101052).</span></em></p><p class="fine-print"><em><span>Erich Fitzgerald and Justin W. Adams 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>This newly discovered ancient monk seal is challenging previous theories about how and where monachine seals evolved. It’s the biggest breakthrough in seal evolution research in about 70 years.James Patrick Rule, Palaeontology PhD Candidate, Monash UniversityErich Fitzgerald, Senior Curator, Vertebrate Palaeontology, Museums Victoria Research InstituteFelix Georg Marx, Curator Vertebrates, Te Papa TongarewaJustin W. Adams, Senior Lecturer, Department of Anatomy and Developmental Biology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1379712020-07-01T12:29:43Z2020-07-01T12:29:43ZWith the help of trained dolphins, our team of researchers is building a specialized drone to help us study dolphins in the wild<figure><img src="https://images.theconversation.com/files/344347/original/file-20200626-104510-1vztssl.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C1599%2C1068&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The only way to learn about the sensory abilities of dolphins is with the help of trained dolphins. </span> <span class="attribution"><span class="source">Dolphin Quest</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Human actions have taken a steep toll on whales and dolphins. Some studies estimate that small whale abundance, which includes dolphins, <a href="https://doi.org/10.3354/esr01008">has fallen 87% since 1980</a> and <a href="https://marinedebris.noaa.gov/sites/default/files/mdp_entanglement.pdf">thousands of whales die from rope entanglement</a> annually. But humans also cause less obvious harm. Researchers have found changes in the stress levels, reproductive health and respiratory health of these animals, but this valuable data is extremely hard to collect.</p>
<p>To better understand how people influence the overall health of dolphins, <a href="https://scholar.google.com/citations?user=Z9Z9u2EAAAAJ&hl=en&oi=sra">my colleagues and I</a> at Oklahoma State University’s <a href="https://ceat.okstate.edu/usri/index.html">Unmanned Systems Research Institute</a> are developing a drone to collect samples from the spray that comes from their blowholes. Using these samples, we will learn more about these animals’ health, which can aid in their conservation.</p>
<h2>The old ways vs. the new way</h2>
<p>Today, researchers wanting to measure wild dolphins’ health primarily use remote biopsy darting – where researchers use a small dart to collect a sample of tissue – or handle the animals in order to collect samples. These methods don’t physically harm the animals, but despite precautions, they can be disruptive and stressful for dolphins. Additionally, this process is challenging, time-consuming and expensive.</p>
<p>My current research focus is on <a href="https://integrativebiology.okstate.edu/8-people/faculty/449-jason-n-bruck">dolphin perception</a> – how they see, hear and sense the world. Using my experience, I am part of a team building a drone specifically designed to be an improvement over current sampling methods, both for dolphins and the researchers. Our goal is to develop a quiet drone that can fly into a dolphin’s blind spot and collect samples from the mucus that is mixed with water and air sprayed out of a dolphin’s blowhole when they exhale a breath. This is called the blow. Dolphins would experience less stress and teams could collect more samples at less expense.</p>
<p>[<em>Get our best science, health and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p>
<p>Some researchers already use <a href="https://doi.org/10.3389/fmars.2017.00425">drones to sample blows from large and small whales</a>. But those animals are not easily startled and have huge blow fields that throw droplets far into the air and linger for a long time. Dolphin blows spray seawater, air and hormone-containing mucus from their blowholes at <a href="https://doi.org/10.1242/jeb.126870">nearly 200 mph and last for about 0.3 seconds</a>. Additionally, dolphins may have <a href="https://doi.org/10.1242/jeb.053397">better hearing than humans</a> and have eyes on both sides of their head that can see in <a href="https://doi.org/10.1016/0077-7579(72)90008-7">both air and water</a>. Good luck sneaking up on a dolphin. </p>
<p>Other teams have attempted to collect samples from dolphins using commercial drones, but it seems the animals’ movements <a href="https://doi.org/10.1002/ecs2.2901">limit the success of these attempts with these devices</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344346/original/file-20200626-104529-8ib2qi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers work with trained dolphins to learn more about their sensory abilities, seen here testing a dolphin’s hearing.</span>
<span class="attribution"><span class="source">Jason Bruck</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>A lot to learn from hormones</h2>
<p>When sampling the blow, we are looking for hormones in mucus as these can be used to gauge psychological and physiological health. We are specifically interested in <a href="https://dx.doi.org/10.1371%2Fjournal.pone.0114062">hormones like cortisol</a> and <a href="https://doi.org/10.1016/j.ygcen.2018.04.003">progesterone</a>, which indicate stress levels and reproductive ability respectively, but can also help determine overall health.</p>
<p>Additionally, blow samples can detect <a href="https://dx.doi.org/10.1128%2FmSystems.00119-17">respiratory pathogens</a> in the lungs or nasal passages - blowholes evolved from noses after all. </p>
<p>This health analysis is especially important in areas with oil spills as the chemicals can cause hormonal problems that harm <a href="https://www.carmmha.org/investigating-how-oil-spills-affect-dolphins-and-whales/">development, metabolism and reproduction</a> in dolphins.</p>
<p>Hormone samples can provide scientists with valuable data, but collecting them from intelligent and unpredictable animals is challenging. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344340/original/file-20200626-104494-1vhfqx1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wild dolphins are fast, smart and can roam thousands of miles and disappear beneath the waves at a moment’s notice.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/dolphins-in-the-ocean-royalty-free-image/1210381908?adppopup=true">Borchee/E+ via Getty Images</a></span>
</figcaption>
</figure>
<h2>Cetacean collaborators</h2>
<p>To build a drone that can stealthily collect spray from moving dolphins, we needed more data on their eyesight and hearing, and this is data that couldn’t be collected in the wild nor simulated in a lab. </p>
<p>We worked with dolphins at facilities like Dolphin Quest in Bermuda, which provides guests opportunities to learn about dolphins while allowing <a href="https://dolphinquest.com/about-us/our-story/">scientists access to animals for noninvasive research</a>. Here the dolphins can swim away if they choose not to work with us, so we had to design the study like a game; the way a kindergarten teacher entertains a class. If the dolphins aren’t interested, we don’t get to do the science.</p>
<p>Over the course of hundreds of sessions, we sought to answer two questions: What can dolphins hear and what can they see around their heads? </p>
<p>To test dolphin hearing, we set up microphones and cameras to record dolphin behavior as we played drone noise in the air. We analyzed the responses to each noise – such as how many dolphins looked at the speaker – and used these as a proxy for their ability to hear the sounds. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UjmQeH3vXHI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">To test the range of a dolphin’s vision, researchers trained the dolphin to whistle any time it saw a light turn on within the sphere. (Turn on sound to hear the dolphin whistle.) Credit: Dolphin Quest.</span></figcaption>
</figure>
<p>To test vision, we mounted lights inside a Hobermann sphere – the expandable rainbow plastic sphere you can see in the video above – that we can turn on and off. The dolphins were trained to whistle when they saw a light around their head. By turning on one light on at a time – which you can watch <a href="https://www.youtube.com/watch?v=7FAaV2Mc0uc">in this video</a> – we created a map of the dolphin’s field of view. </p>
<p>Next, we needed to understand the blow and a means to practice drone flights without a dolphin. To do this, graduate students built robodolphin, which includes a mechanical dolphin lung and replica of the blowhole.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=355&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=355&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=355&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=446&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=446&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344325/original/file-20200626-104484-1wrzdcv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=446&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Robodolphin doesn’t look like a real dolphin, but it doesn’t need to in order to train our drone pilots.</span>
<span class="attribution"><span class="source">C.J. Barton; Oklahoma State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>To build robodolphin, we worked with dolphins trained to “chuff” or sneeze on command to measure spray characteristics. We used high-speed photography to see the dolphins’ breath as it moved through the air. Then we conducted high resolution CT scans of a dolphin head and 3D-printed a replica of a nasal passage. </p>
<p>Now, we have a complete robodolphin and are tweaking its sprays to be nearly identical to the real thing. This will allow us to determine how close we need to get to collect the samples, and therefore, how quiet our drone needs to be.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344327/original/file-20200626-104538-1unx0q8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The replica dolphin blowhole was designed from a scan of a real blowhole passage, and the spray it produces closely matches the real thing.</span>
<span class="attribution"><span class="source">Alvin Ngo, Mitch Ford and CJ Barton; Oklahoma State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>A bit of practice, then into the wild</h2>
<p>In the next few months, we will test flights over robodolphin with existing drones to determine the timing and strategy for collection. From there, we will fabricate a low-noise drone that can fly fast enough and with sufficient maneuverability to capture samples from wild dolphins. Like a video game, we will use the visual field data to develop approach trajectories to stay in the visual blindspots. </p>
<p>We plan to test our drones on a truck-mounted robodolphin moving down a runway, then using a boat to simulate realistic conditions. The next steps will involve ocean testing with dolphins trained for open ocean swimming. These tests will determine if our devices can catch and hold the hormones as the drone flies back to a researcher’s boat.</p>
<p>Finally, we will deploy the system to collect data on wild dolphins. Our first goal is to test resident dolphins – animals that live on the coasts and deal directly with boat and oil industry noise – which will allow us to learn more about stress resulting from human impacts.</p>
<p>Those samples are a way off, but if all goes well we will have a specially built drone capable of flying long distances and capturing samples undetected in a few years. The samples collected will allow researchers to do better science with impact on the animals they study.</p><img src="https://counter.theconversation.com/content/137971/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Bruck has received conservation research funding from Dolphin Quest.</span></em></p>Wild dolphins are fast, smart and hard to study, but it is important to understand how human actions affect their health. So we are building a drone to sample hormones from the blowholes of dolphins.Jason Bruck, Teaching Assistant Professor of Integrative Biology, Oklahoma State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1312962020-04-01T18:26:19Z2020-04-01T18:26:19ZAs ships move north with climate change, their noise scares Arctic cod away<figure><img src="https://images.theconversation.com/files/316627/original/file-20200221-92507-4kidcp.JPG?ixlib=rb-1.1.0&rect=131%2C108%2C4524%2C3018&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A cruise ship leaves Resolute Bay, Nunavut, in the summer of 2014. </span> <span class="attribution"><span class="source">(Silviya V. Ivanova)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>When people who haven’t been to the Arctic think of this remote and cold region, they may picture animals, such as polar bears, narwhal or ringed seals, and the people who live there. Rarely does this vision include modern cargo ships and ocean liners. </p>
<p>Yet these large vessels are increasing their activity in the Arctic Ocean as declining sea ice opens previously inaccessible Arctic regions to shipping. This surge in vessel traffic is also causing an increase in underwater noise, which research has shown can affect <a href="https://doi.org/10.3389/fmars.2019.00606">marine mammals</a> and <a href="https://doi.org/10.1139/cjfas-2017-0418">fish</a> by interfering with communications, behaviour and movement.</p>
<p>Our <a href="https://doi.org/10.1002/eap.2050">new study shows that Arctic cod</a>, a key fish in this ecosystem, are also sensitive to ship noise. Such sensitivity may affect their well-being and the predators that feed on them. </p>
<h2>Noise disruptions</h2>
<p>Most <a href="https://doi.org/10.1016/j.tree.2010.04.005">fish and marine mammals can hear sound</a>, which they use to communicate, forage, detect approaching predators and locate prey. Noise in the environment can impede all of these functions, and this can have negative short- or long-term implications for the health of aquatic organisms. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/324429/original/file-20200331-65503-6brbk6.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">Arctic cod are slender fish that range further north than any other fish.</span>
<span class="attribution"><span class="source">(Erling Svensen/Ocean Photo)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>For example, noise-induced temporary hearing loss and an <a href="https://doi.org/10.1016/j.biocon.2005.10.020">increase in stress hormones</a> have been observed in fish. The former <a href="https://doi.org/10.1038/ncomms10544">can lead to death</a> due to inability to hear approaching predators. <a href="https://doi.org/10.1016/S0065-3454(05)35004-2">Masked communication</a> can also lead to loss of critical mating opportunities.</p>
<p>Some Arctic communities have raised concerns about the effect increasing ship traffic might have on aquatic animals, particularly marine mammals that are an important source of food and livelihood. They also worried that the noise might be pushing the Arctic cod into new areas, followed by marine mammals.</p>
<p>We carried out a study in Resolute Bay, Nunavut, to measure how ship noise might be changing the behaviour of Arctic cod, an abundant small fish that is a key prey for seals, whales and seabirds. </p>
<h2>Missed meals</h2>
<p>We used <a href="https://doi.org/10.1126/science.1255642">acoustic telemetry</a> to track 77 individual Arctic cod. <a href="https://doi.org/10.1002/eap.2050">We found they moved</a> to areas with less noise when cargo ships and cruise ships were present in the bay, whether they were anchored or moving. </p>
<p>Cod form schools, so we assumed that the fish we were tracking represented the population living in Resolute Bay. When ship activity was low (a single ship), the cod moved 250-350 metres away.</p>
<p>We would expect the displacement to be larger with more ship activity. In recent years, two ships are commonly seen in the bay at once. There has also been a sharp increase in the traffic through the Parry Channel — the main passage running through Lancaster Sound — over the past decade.</p>
<p>Any shift, whether short- or long-term, in the distribution of an animal’s population has implications for that species and for the predators that rely on them. As the <a href="https://www.jstor.org/stable/40509298">primary food source of seabirds and marine mammals</a>, a shift in Arctic cod distribution has consequences for the marine food webs, as well as for the Indigenous communities that depend on them. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/324433/original/file-20200331-65495-1tqnck2.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">Marine mammals are an important source of food for many Arctic Indigenous communities.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/arctictraveler/3078048549">(Judith Slein/Flickr)</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Summer is a short but critical period in the Arctic. Fish, birds and marine mammals feed prolifically in open waters when prey is more abundant. The warmer temperatures also allow animals to grow faster and accumulate more body fat. </p>
<p>We found Arctic cod changed their swimming behaviour when ships were present, spending less time searching for and consuming food, and more time travelling, which is associated with higher speeds and thus, more energy use. </p>
<p>But if ship traffic occurs in an important feeding area for Arctic cod, the fish may find themselves missing meals and using more energy for travel. This could have significant negative effects. For example, it may lead to <a href="https://doi.org/10.4319/lo.1970.15.6.0839">lower body weight</a> or <a href="https://doi.org/10.1007/s004420050112">reduced winter survival</a> due to lower fat reserves.</p>
<h2>Under pressures</h2>
<p>Ship traffic in Arctic Canada has already <a href="https://www.onepetro.org/conference-paper/ISOPE-I-10-601">doubled over the past 20 years</a>, and the number of days ships spend in the Arctic has nearly quadrupled since 2000. This <a href="https://doi.org/10.1002/2016GL069315">trend is also seen elsewhere in the Arctic and is projected to continue</a>. The Northwest Passage, a sea route through the Canadian Arctic Archipelago, has long been eyed for shipping to Asia from North America and Europe. As vessel traffic grows, underwater noise will also continue to increase. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=569&fit=crop&dpr=1 600w, https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=569&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=569&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=716&fit=crop&dpr=1 754w, https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=716&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/324431/original/file-20200331-65495-j16g06.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=716&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Map of the Arctic region showing the Northeast Passage the Northern Sea Route and Northwest Passage and bathymetry.</span>
<span class="attribution"><span class="source">(Arctic Council)</span></span>
</figcaption>
</figure>
<p>Underwater ship noise is a new disturbance to Arctic marine animals. Although fish from temperate regions have shown the ability to adapt to noise, Arctic organisms may not have enough time to adjust. </p>
<p>The effects of climate change are greatest at the poles and the organisms there already face many stressors. The <a href="https://www.arcticbiodiversity.is/index.php/the-report/chapters/marine-ecosystems">Arctic ecosystem</a> also has lower species diversity compared with temperate and tropical climates, reducing its resilience to stress. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-fishy-problem-of-underwater-noise-pollution-91547">The fishy problem of underwater noise pollution</a>
</strong>
</em>
</p>
<hr>
<p>Although Canada, Europe and the United States broadly support environmental protection, human health and sustainable management of anthropogenic disturbances, such as ship traffic and noise, we need to develop and implement effective conservation and management plans. </p>
<p>We need Indigenous people to be involved in decision-making processes, <a href="https://www.dfo-mpo.gc.ca/oceans/publications/tuvaijuittuq/designation/index-eng.html">marine protected areas that protect important foraging and breeding grounds</a>, strict rules on ship speed and their distance from sensitive regions, as well as <a href="https://www.portvancouver.com/wp-content/uploads/2017/01/Vessel-Quieting.pdf">technologies that lower vessel noise</a>, such as modified propellers and regular cleanings. </p>
<p>The precautionary principle in environmental decision-making suggests we should take preventive action in the face of uncertainty. For the Arctic, uncertainty is associated to the response of biology in the oceans and on land and its magnitude. We believe that preventive timely action is of the essence.</p><img src="https://counter.theconversation.com/content/131296/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Silviya V. Ivanova receives funding from the Natural Science and Engineering Research Council of Canada (NSERC), and the University of Windsor.</span></em></p><p class="fine-print"><em><span>Aaron Fisk receives funding from the Natural Science and Engineering Research Council of Canada (NSERC), Canadian Foundation for Innovation (CFI), Canada Research Chairs, and the Pew Charitable Trust.</span></em></p>Arctic cod are key prey for seals, whales and seabirds. What happens when ship noise drives them away?Silviya V. Ivanova, PhD Candidate, Great Lakes Institute for Environmental Research (GLIER), University of WindsorAaron Thomas Fisk, Professor, School of the Environment, University of WindsorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1299102020-02-03T02:55:56Z2020-02-03T02:55:56ZDeep impact: grey seals clap underwater to communicate<figure><img src="https://images.theconversation.com/files/310810/original/file-20200120-118319-yw3uzm.jpg?ixlib=rb-1.1.0&rect=2%2C8%2C1914%2C850&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Ben Burville</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Have you ever clapped your hands to get someone’s attention? The resulting “crack!” sound is hard to ignore, rising above and penetrating through any background noise. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=571&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=571&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310797/original/file-20200120-118319-1bumfo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=571&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p>Now imagine trying to do it underwater – you would be unlikely to achieve quite the same impact.</p>
<p>Amazingly, new footage released this week in the journal <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mms.12666">Marine Mammal Science</a> shows breeding grey seals doing just that: they clap at each other to warn off competitors and attract potential mates. </p>
<figure>
<iframe src="https://player.vimeo.com/video/385880959" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Grey seal clapping underwater. Filmed by Ben Burville as part of Project Grypus.</span></figcaption>
</figure>
<h2>Why is this unusual?</h2>
<p>Like their land-living relatives, marine mammals primarily communicate vocally - think of dolphin whistles or the famous song of humpback whales. Grey seals are no exception, and in fact can be surprisingly versatile. </p>
<p>Besides the bizarre “rup” and “rupe” calls these seals normally make in the wild (see the video below), some captive animals have even been trained to perform the <a href="https://www.newscientist.com/article/2207264-seals-have-been-trained-to-sing-the-star-wars-theme-have-a-listen/">Star Wars theme tune</a>!</p>
<p>But vocals are only half the story. Many marine mammals also produce percussive sounds, such as by slapping the water with their flippers or tails. Normally this happens at the surface, and only involves one flipper at a time. </p>
<p>What makes grey seals different is that - like humans - they literally clap their forelimbs together, and they do it entirely underwater.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sharp-claws-helped-ancient-seals-conquer-the-oceans-92828">Sharp claws helped ancient seals conquer the oceans</a>
</strong>
</em>
</p>
<hr>
<h2>The behaviour that took 17 years to film</h2>
<p>Recording the claps was far from easy, and took no less than 17 years of scuba diving by “seal diver” and marine biologist <a href="https://twitter.com/Sealdiver">Ben Burville</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=357&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=357&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=357&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=448&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=448&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310796/original/file-20200120-118352-q7q5en.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=448&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Seal diver Ben Burville with one of his dive buddies - a wild grey seal off the Farne Islands, UK.</span>
<span class="attribution"><span class="source">Photo provided by Ben Burville.</span></span>
</figcaption>
</figure>
<p>Ben was no stranger to the clapping sound itself. For years, he had heard it when diving with grey seals during their breeding season. Similar noises had also been detected by researchers using underwater microphones, but had been mistaken for a vocal signal. </p>
<p>It wasn’t until he actually saw a big male clapping together its paw-like flippers that Ben finally identified the true source of the sound. Yet the claps were quick and difficult to film; by the time he pointed his camera, things had usually moved on.</p>
<p>Years passed until finally, in October 2017, Ben caught the behaviour on film while diving near the Farne Islands, UK. A male grey seal performed seven claps right in front of him while his camera was rolling.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=289&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=289&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=289&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=363&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=363&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310836/original/file-20200120-69559-1pe6c4k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=363&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Grey seals use their short paw-like forelimbs to make loud clapping sounds underwater.</span>
<span class="attribution"><span class="source">Filmed by Ben Burville. Illustrations by David Hocking.</span></span>
</figcaption>
</figure>
<h2>Why do grey seals clap?</h2>
<p>At first, the discovery might not seem that surprising. After all, seals are famous for performing this behaviour in zoos and aquaria. However, there is a crucial difference: whereas captive animals (usually fur seals or sea lions) have been trained to clap for our entertainment, grey seals do so in the wild and of their own accord. </p>
<p>So why do they do it?</p>
<p>Imagine being in a noisy room, with everyone around you chatting away. Getting attention can be difficult, unless you make a statement. That’s exactly what a clap is: a sharp, loud noise that rises above the background chatter. </p>
<p>Usually it’s males that do the clapping - sometimes by themselves, and sometimes at each other. Depending on the context, the claps may help ward off competitors and/or attract potential mates. </p>
<p>Similar functions underlie display behaviour in many other species. Think of a chest-beating male gorilla, for example. Like seal claps, those chest beats carry two messages: “I am strong, stay away”, and “I am strong, my genes are good.”</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EAkxix31aJI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Male gorillas beat their chest as a show of strength to competitors and potential mates.</span></figcaption>
</figure>
<h2>Do other marine mammals clap?</h2>
<p>The short answer seems to be no, or at least not as far as we know. Clapping seems to be a genuinely novel behaviour that evolved in seals only once. Perhaps larger species such as sea lions are prevented from doing it by increased water resistance.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310821/original/file-20200120-118347-halxbk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Australian sea lions have long flipper-like forelimbs that may create too much drag to clap effectively underwater.</span>
<span class="attribution"><span class="source">Photo by David Hocking</span></span>
</figcaption>
</figure>
<p>Of course, it is also possible that some other species also clap, but haven’t done so in front of a camera. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-mammals-took-to-water-they-needed-a-few-tricks-to-eat-their-underwater-prey-73770">When mammals took to water they needed a few tricks to eat their underwater prey</a>
</strong>
</em>
</p>
<hr>
<p>Even if clapping were unique to grey seals, it seems the sharp signal it generates is important for many marine mammals. Several dolphins, whales and seals produce similar sounds via tail or flipper slaps, or even gunshot-like vocalisations. The oceans are a noisy place, after all, and it can be important to stand out in a crowd. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Vo31hoY1NUA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Wild harbour seal slapping the water to create a loud noise - possibly to scare fish out of hiding so that they can be caught.</span></figcaption>
</figure>
<h2>What should we learn from this?</h2>
<p>Clapping seals show us just how much we still don’t know about the remarkable mammals in our oceans. Clapping seems to be an important social behaviour, hence anything that disturbs it may impact breeding success and survival. </p>
<p>Human noise pollution is known to interfere with other forms of marine mammal communication, including <a href="https://thewire.in/the-sciences/how-noise-pollution-is-silencing-whale-songs-and-why-thats-a-problem">whale song</a>. Loud industrial noises could conceivably disturb grey seals (and other species that rely on acoustic signals) in similar ways. </p>
<p>But if we do not know a behaviour exists, we cannot easily act to protect it. </p>
<p>Understanding the animals around us better can therefore help us to protect them and their way of life.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=342&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=342&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=342&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=430&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=430&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311034/original/file-20200121-144971-wloh9g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=430&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Photo by Ben Burville</span></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/129910/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Hocking receives funding from from Monash University and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Felix Georg Marx received funding from from the Australian Research Council (DECRA fellowship DE190101052). </span></em></p><p class="fine-print"><em><span>Ben Burville 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>Clapping underwater takes real strength. But wild grey seals can do it, to warn off competitors and attract potential mates.David Hocking, Postdoctoral fellow, Monash UniversityBen Burville, Visiting Researcher - Marine Biology, Newcastle UniversityFelix Georg Marx, Curator Vertebrates, Te Papa TongarewaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1285122020-01-15T13:54:46Z2020-01-15T13:54:46ZMeet the narwhal, ‘unicorn of the sea’<figure><img src="https://images.theconversation.com/files/309978/original/file-20200114-151876-1w18k8d.JPG?ixlib=rb-1.1.0&rect=304%2C330%2C3026%2C1998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Over 100,000 narwhals swim the Earth's Arctic waters.</span> <span class="attribution"><span class="source">Kristin Laidre</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Narwhals are often called the unicorns of the sea. The long tusk of the male narwhal sets these whales apart, but it’s not the only thing that makes <em>Monodon monoceros</em> among the most intriguing and mysterious marine mammals.</p>
<p>A deep-diving cetacean in the odontocete family (which means “toothed whales”), narwhals live in cold Arctic and sub-Arctic waters. They’re highly adapted to <a href="https://doi.org/10.1007/s00227-004-1371-1">living in areas almost completely covered with sea ice</a>. Narwhals are among the only whales that live in areas with such dense sea ice cover for up to six months each winter.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308224/original/file-20191223-11900-12ebhgl.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">Laidre and colleagues spot narwhals from shore in northwest Greenland.</span>
<span class="attribution"><span class="source">D. Rees</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>As a <a href="https://staff.washington.edu/klaidre/">scientist who studies animal ecology in the Arctic</a>, I know firsthand that seeing a narwhal in the wild is a special experience. They usually travel in pods and can be quite sneaky. When they pass by, you may only see a small sliver of their mottled black and white skin above the water when they surface to breathe. No wonder glimpses of these whales and their unique tusks have fueled myths for centuries.</p>
<h2>The tusk that is the narwhal’s claim to fame</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=665&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=665&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=665&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=836&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=836&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310078/original/file-20200114-151844-uuy3ci.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=836&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nature’s only spiral tooth is found in the male narwhal.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/narval-sea-unicorn-horn-detail-1371351476">Andrea Izzotti/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>Unlike all other toothed whales, the narwhal actually has no teeth in its mouth. Instead, the <a href="https://www.penumbrapress.com/book.php?id=10">male develops a long straight tooth</a>, called a tusk, that protrudes 6 to 10 feet out of his upper left jaw. A long tusk on an adult male can be more than half the usual total body length of about 16 feet. The tooth grows in a counterclockwise spiral – nature’s only spiral tooth.</p>
<p>The tusk is essentially unique to male narwhals. Very rarely, a female will grow a tusk, or even more rarely a male narwhal will grow two. Tusks exported from the Arctic, perhaps by the Vikings, <a href="https://en.wikipedia.org/wiki/Throne_Chair_of_Denmark">reached Europe</a>, the Mediterranean and even the Far East as early as the Middle Ages and became the <a href="http://www.slate.com/blogs/atlas_obscura/2015/06/23/the_ceremonial_throne_of_denmark_passes_off_narwhal_tusk_as_unicorn_horn.html">source of the unicorn myth</a>. The tusks were sold to the very rich without a good description of the animal from which they came and inspired a <a href="https://www.lrb.co.uk/the-paper/v41/n01/katherine-rundell/consider-the-narwhal">great deal of fantasy</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308152/original/file-20191220-11951-1w9dwow.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Danish coronation chair from the 1600s is made of narwhal tusks.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Rosenborg_Palace,_Copenhagen,_early_1600s_(7)_(36237310202).jpg">Richard Mortel/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>To some extent, tusks still inspire fantasies, as people have proposed many unsupported explanations for their purpose – whether breaking ice, sword fighting with other whales, spearing or smacking fish for food, sensing temperatures or digging in the bottom the sea. </p>
<p>One thing is clear: The tusk cannot serve a critical function for narwhals’ survival, because females, who do not have tusks, live just as long as males. And they do it surviving in the same harsh areas, finding the same food and additionally being responsible for reproduction and calf-rearing.</p>
<p>The tusk is <a href="http://darwin-online.org.uk/EditorialIntroductions/Freeman_TheDescentofMan.html">a sexual trait</a>, much like the antlers of a stag, the mane of a lion or the feathers of a peacock. <a href="https://doi.org/10.1139/z81-319">Males use the tusk</a> to determine social rank and compete for females. It is not entirely clear how this works, but male narwhals may be able to visually size each other up as competitors; they may interact with their tusk with some unknown level of aggression underwater; or possibly a female could use the tusk as a visual signal for choosing her mate. </p>
<p>During the summertime in the northern Arctic bays and fjords, male narwhals can be seen interacting at the surface, carefully crossing their tusks and touching them together. Such behavior might help adult males compare themselves and maintain dominance hierarchies. Or perhaps it helps young males nearby learn skills necessary for performance in adult sexual roles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309980/original/file-20200114-93792-126cz0u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&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 pod of narwhals in Northwest Greenland.</span>
<span class="attribution"><span class="source">Kristin Laidre</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Living in a changing Arctic</h2>
<p><a href="https://doi.org/10.1111/acv.12000">Narwhals’ extensive migrations</a> follow the <a href="https://www.wiley.com/en-us/Sea+Ice%2C+3rd+Edition-p-9781118778388">formation and retreat of annual sea ice</a>. Some can travel thousands of miles in a single year.</p>
<p>The <a href="https://doi.org/10.1111/cobi.12474">over 100,000 narwhals worldwide</a> today are <a href="https://doi.org/10.1111/acv.12000">divided into subpopulations</a> of between a few thousand to up to 30,000 animals, based on where they spend the summer, in ice-free bays and fjords or at glacial fronts. In autumn, they migrate to <a href="https://doi.org/10.3354/meps261269">overwintering areas</a> that are <a href="https://doi.org/10.3354/meps08941">deep, offshore and ice-covered</a>, usually along the continental slope. <a href="https://doi.org/10.1111/j.1748-7692.2005.tb01207.x">Most feeding takes</a> <a href="https://doi.org/10.3354/meps261269">place in winter</a>, and then females give birth in spring.</p>
<p>During the winter months in the dense pack ice, narwhals can make dives that are over a mile deep, sometimes swimming upside down as they descend into pitch black water. They sometimes seek prey close to the bottom, such as Greenland halibut, and swallow them whole.</p>
<p>Narwhals are part of an Arctic environment that is rapidly changing. The region is warming twice as fast as the rest of the world – <a href="https://doi.org/10.1126/sciadv.aaw9883">1.35 degrees Fahrenheit (0.75 degrees Celsius)</a> in the last decade alone. By comparison, it’s taken the Earth as a whole the past 137 years to warm by nearly the same amount, 0.8°C.</p>
<p>In order to understand how narwhals may or may not adapt to the climate change in the Arctic, it is vital to develop a basic understanding of their ecology. Furthermore, narwhals are an important cultural, nutritional and economic resource for native communities in Greenland and Canada. My colleagues and I are continuing to study the structure and dynamics of narwhal populations in a changing climate, in hopes we can conserve their populations and ensure they remain sustainable biological resources.</p>
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<p class="fine-print"><em><span>Kristin Laidre receives funding from The National Science Foundation (NSF), National Aeronautics and Space Administration (NASA), and Office of Naval Research (ONR). </span></em></p>The long tusk of the male narwhal earned these whales their fanciful nickname. But there’s more to these Arctic mammals than their unique spiral tooth.Kristin Laidre, Associate Professor of Aquatic and Fishery Sciences, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1282222019-12-12T19:03:00Z2019-12-12T19:03:00ZWhy are whales big, but not bigger?<figure><img src="https://images.theconversation.com/files/306633/original/file-20191212-85417-hq31z6.JPG?ixlib=rb-1.1.0&rect=0%2C0%2C5176%2C3437&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Minke whale.</span> <span class="attribution"><span class="source">Jeremy Goldbogen</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Both toothed and baleen (filter-feeding) whales are among the largest animals ever to exist. Blue whales, which measure up to 100 feet (30 meters) long and can weigh over 150 tons, are the largest animals in the history of life on Earth. </p>
<p>Although whales have existed on this planet for some 50 million years, they only evolved to be truly gigantic in <a href="https://doi.org/10.1098/rspb.2017.0546">the past five million years or so</a>. Researchers have little idea <a href="https://doi.org/10.1073/pnas.1804077115">what limits their enormous size</a>. What is the pace of life at this scale, and what are the consequences of being so big?</p>
<p>As scientists who study <a href="https://scholar.google.com/citations?user=uo1sSBwAAAAJ&hl=en">ecology</a>, <a href="https://scholar.google.com/citations?user=CBjDcy8AAAAJ&hl=en">physiology</a> and <a href="https://scholar.google.com/citations?user=TPY3-ccAAAAJ&hl=en">evolution</a>, we are interested in this question because we want to know the limits to life on Earth, and what allows these animals to live at such extremes. In a <a href="https://science.sciencemag.org/content/366/6471/1367">newly published study</a>, we show that whale size is limited by the largest whales’ very efficient feeding strategies, which enable them to take in a lot of calories compared to the energy they burn while foraging.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306194/original/file-20191210-95149-1orahti.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 humpback whale approaches scientists in the Antarctic.</span>
<span class="attribution"><span class="source">Goldbogen Laboratory, Stanford University / Duke University Marine Robotics and Remote Sensing, taken under permit ACA / NMFS #14809</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Ways to be a whale</h2>
<p>The first whales on Earth had four limbs, <a href="https://ocean.si.edu/through-time/ancient-seas/evolution-whales-animation">looked something like large dogs</a> and lived at least part of their lives on land. It took about 10 million years for their descendants to evolve a completely aquatic lifestyle, and roughly 35 million years longer for whales to become the giants of the sea. </p>
<p>Once whales became completely aquatic some 40 million years ago, the types that succeeded in the ocean were either <a href="https://en.wikipedia.org/wiki/Baleen_whale">baleen whales</a>, which fed by straining seaweater through baleen filters in their mouths, or <a href="https://en.wikipedia.org/wiki/Toothed_whale">toothed whales</a> that hunted their prey using <a href="https://en.wikipedia.org/wiki/Animal_echolocation">echolocation</a>. </p>
<p>As whales evolved along these two paths, a process called <a href="https://en.wikipedia.org/wiki/Upwelling">oceanic upwelling</a> was intensifying in the waters around them. Upwelling occurs when strong winds running parallel to the coast push surface waters away from the shore, drawing up cold, nutrient-rich waters from the deep ocean. This stimulates plankton blooms.</p>
<figure class="align-center zoomable">
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<figcaption>
<span class="caption">Upwelling occurs when winds displace surface waters, which are replaced by cold, nutrient-rich water that wells up from below.</span>
<span class="attribution"><a class="source" href="https://oceanservice.noaa.gov/facts/upwelling.html">NOAA</a></span>
</figcaption>
</figure>
<p>Stronger upwelling created the right conditions for baleen whale prey, such as <a href="https://en.wikipedia.org/wiki/Krill">krill</a> and <a href="https://en.wikipedia.org/wiki/Forage_fish">forage fish</a>, to become concentrated in dense patches along coastlines. Whales that fed on these prey resources could forage efficiently and predictably, allowing them to grow larger. <a href="https://doi.org/10.1098/rspb.2017.0546">Fossil records</a> showing that baleen whale lineages separately became gigantic all at the same time support this view. </p>
<h2>Really big gulps</h2>
<p>Is there a limit to how big whales can become? We tackled this question by drawing on animal energetics – the study of how efficiently organisms ingest prey and turn the energy it contains into body mass. </p>
<p>Getting large is based on simple math: If a creature can gain more calories than it spends, it gets bigger. This may seem intuitive, but demonstrating it with data collected from free-living whales was a gargantuan challenge. </p>
<p>To get the information, our international team of scientists attached high-resolution tags with suction cups to whales so that we could track their orientation and movement. The tags recorded hundreds of data points per second, then detached for recovery after about 10 hours. </p>
<p>Like a Fitbit that uses movement to record behavior, our tags measured how often whales fed below the ocean’s surface, how deep they dove and how long they remained at depth. We wanted to determine each species’ energetic efficiency – the total amount of energy that it gained from foraging, relative to the energy it expended in finding and consuming prey. </p>
<figure class="align-center zoomable">
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<figcaption>
<span class="caption">Tagged blue whale off the coast of Big Sur, California.</span>
<span class="attribution"><span class="source">Duke Marine Robotics & Remote Sensing under NMFS permit 16111</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Data in this study was provided by collaborators representing six countries. Their contributions represent tens of thousands of hours of fieldwork at sea collecting data on living whales from pole to pole.</p>
<p>In total, this meant tagging 300 toothed and baleen whales from 11 species, ranging from five-foot-long <a href="https://www.fisheries.noaa.gov/species/harbor-porpoise">harbor porpoises</a> to <a href="https://www.fisheries.noaa.gov/species/blue-whale">blue whales</a>, and recording more than 50,000 feeding events. Taken together, they showed that whale gigantism is driven by the animals’ ability to increase their net energy gain using specialized foraging mechanisms. </p>
<p>Our key finding was that <a href="https://en.wikipedia.org/wiki/Rorqual">lunge-feeding baleen whales</a>, which engulf swarms of krill or forage fish with enormous gulps, get the most bang for their buck. As these whales increase in size, they use more energy lunging – but their gulp size increases even more dramatically. This means that the larger baleen whales get, the greater their energetic efficiency becomes. We suspect the upper limit on baleen whales’ size is probably set by the extent, density and seasonal persistence of their prey.</p>
<p>Large toothed whales, such as <a href="https://en.wikipedia.org/wiki/Sperm_whale">sperm whales</a>, feed on large prey occasionally including the fabled <a href="https://ocean.si.edu/ocean-life/invertebrates/giant-squid">giant squid</a>. But there are only so many giant squid in the ocean, and they are hard to find and capture. More frequently, large toothed whales feed on medium-sized squid, which are much more abundant in the deep ocean.</p>
<p>Because of a lack of large enough prey, we found that toothed whales’ energetic efficiency decreases with body size – the opposite of the pattern we documented for baleen whales. Therefore, we think the ecological limits imposed by a lack of giant squid prey prevented toothed whales from evolving body sizes greater than sperm whales. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=486&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=486&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=486&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=611&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=611&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306463/original/file-20191211-95125-1g2hvmg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=611&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scaling of energetic efficiency in toothed whales and baleen whales.</span>
<span class="attribution"><a class="source" href="http://www.alexboersma.com">Alex Boersma</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>One piece of a larger puzzle</h2>
<p>This work builds on previous research about the <a href="https://doi.org/10.1098/rsbl.2016.0186">evolution of body size in whales</a>. Many questions remain. For example, since whales developed gigantism relatively recently in their evolutionary history, could they evolve to be even larger in the future? It’s possible, although there may be other physiological or biomechanical constraints that limit their fitness. </p>
<p>For example, <a href="https://doi.org/10.1073/pnas.1914273116">a recent study</a> that measured blue whale heart rates demonstrated that heart rates were near their maximum even during routine foraging behavior, thereby suggesting a physiological limit. However, this was the first measurement and much more study is needed.</p>
<p>We would also like to know whether these size limits apply to other big animals at sea, such as sharks and rays, and how baleen whales’ consumption of immense quantities of prey affect ocean ecosystems. Conversely, as human actions alter the oceans, could they affect whales’ food supplies? Our research is a sobering reminder that relationships in nature have evolved over millions of years – but could be disrupted far more quickly in the <a href="https://en.wikipedia.org/wiki/Anthropocene">Anthropocene</a>. </p>
<p>[ <em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklysmart">You can get our highlights each weekend</a>. ]</p><img src="https://counter.theconversation.com/content/128222/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Savoca receives funding from the National Science Foundation. </span></em></p><p class="fine-print"><em><span>Jeremy Goldbogen receives funding from the National Science Foundation and the Office of Naval Research. </span></em></p><p class="fine-print"><em><span>Nicholas Pyenson receives funding from the Smithsonian Institution.</span></em></p>How did whales that feed on tiny prey evolve into the largest creatures on Earth? And why don’t they get even bigger?Matthew Savoca, Postdoctoral researcher, Stanford UniversityJeremy Goldbogen, Assistant Professor of Biology, Stanford UniversityNicholas Pyenson, Research Geologist and Curator of Fossil Marine Mammals, Smithsonian InstitutionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1227482019-11-07T21:15:49Z2019-11-07T21:15:49ZClimate change and overfishing are boosting toxic mercury levels in fish<figure><img src="https://images.theconversation.com/files/300736/original/file-20191107-10910-a8ipmr.jpg?ixlib=rb-1.1.0&rect=234%2C128%2C4325%2C2664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mercury levels in Pacific sardines could rise by as much as 14 per cent if greenhouse gas emissions continue to rise.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>We live in an era — the Anthropocene — where humans and societies are reshaping and changing ecosystems. Pollution, human-made climate change and overfishing have all altered marine life and ocean food webs. </p>
<p>Increasing ocean temperatures are <a href="https://doi.org/10.1038/s41598-018-31824-5">amplifying the accumulation of neurotoxic contaminants such as organic mercury (methylmercury) in some marine life</a>. This especially affects top predators including marine mammals such as fish-eating killer whales that strongly rely on large fish as seafood for energy. </p>
<p>Now the combination of mercury pollution, climate change and overfishing are conspiring together to <a href="https://doi.org/10.1038/s41586-019-1468-9">further contaminate marine life and food webs</a>. This has <a href="https://doi.org/10.1289/ehp.7603">obvious implications for ecosystems and the ocean, but also for public health</a>. The risk of consuming mercury-contaminated fish and seafood is growing with climate change. </p>
<h2>Mercury rising</h2>
<p><a href="https://doi.org/10.1073/pnas.1516312113">Regulations have lowered global mercury emissions from human-made sources, such as coal-fired power plants, between 1990 and 2010</a> but mercury is still present in the marine environment. </p>
<p>Methylmercury builds up in the muscle tissue of fish across the food web, “bioaccumulating” in larger and high trophic level predators. This is why larger pelagic fish (for example, tuna, marlins, billfishes and sharks) — those that eat a lot of fish — are in general considered riskier to eat than smaller ones. </p>
<p>In humans, <a href="https://apps.who.int/iris/bitstream/handle/10665/44445/9789241500456_eng.pdf?sequence=1&isAllowed=y&ua=1">mercury can lead to neurological disorders</a>. Children who are exposed to mercury during fetal development and childhood have a <a href="https://www.who.int/bulletin/volumes/92/4/12-116152.pdf?ua=1">greater risk of poor performance on tests that measure attention, IQ, fine motor function and language</a>.</p>
<p>Climate change can amplify the accumulation of methylmercury in fish and marine mammals at the top of their food webs due to <a href="https://doi.org/10.1111/gcb.13667">changes in the entry and fate of mercury in the ocean and the composition and structure of these marine food webs</a>. A warmer and more acidic ocean may increase the amount of methylmercury that enters the food web. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mercury-decline-in-seabirds-due-to-diet-not-emissions-controls-86724">Mercury decline in seabirds due to diet, not emissions controls</a>
</strong>
</em>
</p>
<hr>
<p>Overfishing can also exacerbate the mercury levels in some fish species. <a href="https://doi.org/10.1038/s41598-018-31824-5">Pacific salmon, squid and forage fish</a>, as well as Atlantic bluefin tuna and Atlantic cod and other fish species are susceptible to increases in methylmercury due to rising ocean temperatures. </p>
<p>Our modelling research work shows that Chinook salmon, the largest Pacific salmon species and main prey of endangered southern resident killer whales, is projected to be exposed to high methylmercury accumulation due to changes in its prey that are driven by climate change. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/300737/original/file-20191107-10973-oqu08i.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">Rising ocean temperatures leave some fish, including tuna, susceptible to increases in methylmercury.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Under a worst-case climate-change scenario, where greenhouse gas emissions continue to increase and global temperatures <a href="https://www.ipcc.ch/report/ar5/wg1/">reach between 2.6C and 4.8C by 2100</a>, Chinook salmon will see a 10 per cent increase in methylmercury. But under a best-case scenario, where emissions are low and global temperature rise is in the order of 0.3C to 1.7C at the end of the century, mercury levels would increase by only one per cent. </p>
<p>For forage fish, such as Pacific sardine, anchovy and Pacific herring, which are key ecological and commercial species in the Pacific Rim ecosystem, the methylmercury increase is projected to be 14 per cent under the influence of high emissions and three per cent under low emissions. Here again, this increase is driven by dietary shifts and changes in the food web composition due to warmer oceans.</p>
<h2>Fishing down the food web</h2>
<p><a href="https://doi.org/10.1016/j.fishres.2019.105314">Atlantic cod stocks were over-exploited along the northeastern coast of Canada during the last century</a>. Chinook salmon stocks from the northeastern Pacific Ocean are also dwindling because of natural factors and environmental stressors, including predation, habitat loss, warming oceans and fishing. The combination of these pressures can make Pacific salmon more susceptible to methylmercury bioaccumulation.</p>
<p>When one species is overfished, fishing fleets expand and adjust their targets, often <a href="https://www.doi.org/10.1126/science.279.5352.860">fishing down the marine food webs</a>. The cascading effects lead to changes in prey and foodweb composition for the remaining species, likely altering the transfer of organic contaminants such as persistent organic pollutants and methylmercury in top predators. </p>
<p>When fish are removed from the food web, larger fish and top predators may be forced to consume more or different prey, or smaller fish than they usually do. These fish can be highly contaminated with mercury.</p>
<p>The combination of climate change and overfishing are further shifting the composition of fish in the ocean and where they are found. They are also altering the way these species are exposed to pollutants, <a href="https://doi.org/10.1038/s41586-019-1468-9">increasing levels of methylmercury in Atlantic cod and Atlantic blue fin tuna</a> — fish that are often eaten by humans. </p>
<h2>Protecting health and the planet</h2>
<p>Based on this evidence, the public health community should revisit and revise fish consumption guidelines for those who are most likely to be exposed to mercury (coastal communities) or experience negative effects (pregnant women, infants and children). </p>
<p>Our simulations show that the projected methylmercury concentrations in forage fish and Chinook salmon will surpass <a href="https://www.canada.ca/en/health-canada/services/food-nutrition/food-safety/chemical-contaminants/maximum-levels-chemical-contaminants-foods.html#a2">Canada’s mercury consumption limits</a> this century, as well as the consumption advisory level issued by the World Health Organization. </p>
<p>In our human-dominated world, it is imperative that we consume fish and shellfish that come from sustainable fisheries and make efforts to reduce ocean pollution. International and national environmental policies, such as the UN <a href="https://sustainabledevelopment.un.org/sdg14#targets">Sustainable Development Goal to conserve and sustainably use the oceans, marine resources and fisheries (SDG 14)</a> and the <a href="https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement">Paris Climate Agreement</a>, can conserve marine species and protect our blue planet for generations to come. </p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/122748/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Juan Jose Alava receives funding from the Nippon Foundation for the Ocean Litter project at the Institute for the Oceans and Fisheries (IOF), University of British Columbia (UBC). He is affiliated as Adjunct Professor with the School of Resources and Environmental Management, Simon Fraser University; and serves as the Science Director (volunteer position) of the Fundacion Ecuatoriana para el Estudio de Mamiferos Marinos (FEMM), Ecuador. Juan Jose is the founder and Principal Investigator of the Ocean Pollution Research Unit (OPRU) at IOF, UBC.</span></em></p>Regulations have lowered mercury emissions globally, but the risks to ocean ecosystems and human health may be getting worse.Juan Jose Alava, Research Associate (Ocean Litter Project)/ Principal Investigator (Ocean Pollution Research Unit), University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1227892019-09-30T05:13:15Z2019-09-30T05:13:15ZCurious Kids: which is smarter – a blue whale or an orca?<figure><img src="https://images.theconversation.com/files/293527/original/file-20190923-23774-6uofxm.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C3493%2C2329&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Blue whales and orcas are both specialists in their own way. You can't really measure which one is more intelligent. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/killer-whale-group-traveling-wild-90045763?src=UI9jSWprc_lTC_CwLvrksg-2-10">Shutterstock</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au.</em> </p>
<hr>
<blockquote>
<p><strong>Which is smarter: blue whales or orcas? – Prasaad, age 6.</strong></p>
</blockquote>
<hr>
<p>There’s no simple answer. We don’t know for sure which one is smarter, because not everyone agrees on what “intelligence” means.</p>
<p>It’s true that blue whales and orcas (also called killer whales) are both smart. They both have very large brains. Orcas have particularly large brains compared to their overall body size.</p>
<p>But it’s not just about brain size. When it comes to measuring intelligence, we might also consider things like:</p>
<ul>
<li>the number of nerve cells in the brain;</li>
<li>ability to navigate the deep, wide oceans;</li>
<li>solving difficult problems;</li>
<li>communicating;</li>
<li>working in teams.</li>
</ul>
<p>Let’s look at which animal is good at which skill.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-sea-creature-can-attack-and-win-over-a-blue-whale-98551">Curious Kids: What sea creature can attack and win over a blue whale?</a>
</strong>
</em>
</p>
<hr>
<h2>What can a blue whale do?</h2>
<p>There’s no doubt a blue whale is a very intelligent animal. </p>
<p>Blue whales eat krill, which are very tiny prawn-shaped animals that gather in huge swarms that are often far away from where blue whales give birth to their children. Despite the distance, blue whales are masters of finding krill. They are very good at navigating along coasts and across the deep, wide oceans.</p>
<p>In fact, blue whales are so smart they can work out if a swarm of krill is worth chasing. Blue whales are very good at finding krill that are fat and in big swarms so they do not waste their energy catching smaller swarms. Blue whales catch krill by rolling on their side and opening their mouths. It is a lot of work and they have to use a lot of energy to do it. </p>
<p>Blue whales also have excellent systems for <a href="https://www.nationalgeographic.com.au/science/blue-whales-and-communication.aspx">communicating</a> with each other. </p>
<h2>What can an orca do?</h2>
<p>Orcas are a kind of large dolphin and they have different strengths.</p>
<p>They are very good at working together. They form groups and hunt together for fish or other sea mammals – including whales. This is why they are called “killer whales”. </p>
<p>They are also expert communicators and have their own language – even certain noises that are <a href="https://www.nrcresearchpress.com/doi/abs/10.1139/z89-105#.XXXnL5MzaV4">used by a particular group</a> of orcas to show they are in the group.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293522/original/file-20190923-23788-cs2v9s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Orcas form groups and hunt together.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pod-killer-whales-swimming-near-surface-723720937?src=WU9ZnnyzAkohfhv4dOT4BQ-1-20">Shutterstock</a></span>
</figcaption>
</figure>
<h2>They both are very intelligent in their own way</h2>
<p>Some scientists have wondered if you could measure intelligence by looking at how well animals teach their children how to behave – for example, how to find food, fight or stay safe. </p>
<p>Orcas are masters at teaching their children exactly what to do. This involves things like hunting in groups or sneaking up on a seal and grabbing it before sliding back into the water. </p>
<p>However, blue whales are also good at teaching their offspring skills such as long-distance navigation – in other words, finding their way around the vast oceans.</p>
<p>Both blue whales and killer whales have their own special behaviours and skills. We really can’t say which one is more intelligent because both are very intelligent in their own way.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-do-creatures-living-in-the-deep-sea-stay-alive-given-the-pressure-111940">Curious Kids: how do creatures living in the deep sea stay alive given the pressure?</a>
</strong>
</em>
</p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/122789/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Kerstin Bilgmann is an Honorary Research Fellow and Research Leader of the Marine Vertebrate Conservation and Evolution Laboratory in the Department of Biological Sciences, Macquarie University, Sydney. </span></em></p>We don’t know for sure which one is smarter, because not everyone agrees on what “intelligence” means. Both have their own special behaviours and skills and we can’t say who is more intelligent.Kerstin Bilgmann, Lecturer in Biological Sciences, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1219092019-09-13T13:15:21Z2019-09-13T13:15:21ZHow diving seals plan ahead to save oxygen – new research<figure><img src="https://images.theconversation.com/files/291997/original/file-20190911-190044-1p82eh3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/harbour-seal-looking-straight-into-camera-546481309?src=oWnL6HhX5OLckB54F_mWhw-1-0">Shutterstock/Pat Stornebrink</a></span></figcaption></figure><p>Seals, dolphins and otters share the same physiological constraints as humans do when we return to our evolutionary home – the sea. The most instantly identifiable of these is the inability to breathe when we put our heads under water. </p>
<p>The difference between where an animal spends most of its time and where it can breathe has had an amazing impact on the physiological capacities of diving mammals – some of the most exceptional athletes on Earth. </p>
<p>For instance, the colossal elephant seal is capable of <a href="http://www.publish.csiro.au/ZO/ZO9910595">holding its breath for two hours</a> and swimming 2km to find food, before covering that distance again for its next breath. </p>
<p>One important physiological tool that enables this lifestyle is greater total body oxygen stores. But oxygen stores alone don’t make a great diver. </p>
<p>What does make a great diver are the cardiovascular responses to diving – regulating the use of oxygen to give prolonged supply to vulnerable parts of the body, such as the brain. The most classic feature of the dive response is a reduction in heart rate, known as <a href="https://jeb.biologists.org/content/221/12/jeb182972.abstract">bradycardia</a>. </p>
<p>It happens in humans too. If you put your face into a full sink, stimulation of sensors in your face, upper airways and throat trigger the deepest and most primal parts of your brain to slow your heart, as well as to pump less blood. </p>
<p>But reduction in heart rate by itself does not reduce the rate of oxygen consumption. It is this, linked to a major redistribution of blood around the body, focusing delivery on the most vital organs, which really conserves oxygen. </p>
<p>This blood redistribution is the essential tool that allows prolonged diving – and so far it has been a difficult thing to study. Because of the nature of diving animals (they dive and swim), technology has to be wearable and non-invasive for an animal that is free to choose where it goes. For it is in this voluntary free-diving state that we can learn the true dynamics of the cardiovascular system and understand how diving animals manage it. </p>
<p>Basically, what we want to do is to let the animals tell us their physiological “story” with minimal interference. And now they can.</p>
<p>A new piece of equipment offering a fresh insight into blood redistribution is a remarkable non-invasive, wearable application of optical technology called “<a href="https://www.ncbi.nlm.nih.gov/pubmed/22510258">near-infrared spectroscopy</a>” or NIRS. </p>
<p>NIRS uses light emitted in contact with the skin (like a FitBit) to measure blood volume and oxygenation in the underlying tissue. The new kit has provided a remarkable new insight in to the dynamics of blood redistribution in diving seals. </p>
<p>Using NIRS on juvenile harbour seals, one of the two species of UK seals, we were able to capture for the first time a level of cardiovascular control that we did not know seals possessed (and frankly, didn’t know existed at all). </p>
<p>Specifically, <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000306">we found</a> that in seals the blood redistribution component of the “dive response” is under some degree of cognitive control. </p>
<p>The seals we observed start to move blood away from their peripheral tissues (in this case blubber and skin) around 15 seconds before they began each dive. This allows seals to prepare for a dive and actually enter into the oxygen conservation state before they go under water, so that when they dive they are not wasting oxygen in the early stages. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292015/original/file-20190911-190031-1k9d9gv.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">Getting ready for oxygen conservation.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/common-harbour-seal-enjoying-evening-sunshine-1458582584?src=oWnL6HhX5OLckB54F_mWhw-1-94">Shutterstock/George Maciver</a></span>
</figcaption>
</figure>
<p>As seals spend 90% of their time at sea diving, these seemingly small savings total up to very significant savings over days, weeks and even months of diving at sea. </p>
<h2>Free diving</h2>
<p>In that sense, the finding of cognitive control of moving blood around the body makes a lot of sense, particularly considering that cognitive control of heart rate has been demonstrated in seals. Seals have <a href="https://www.nature.com/articles/256037a0">already been shown</a> to be able to drop their heart rate on command and also match the reduction in heart rate for the anticipated duration of the following dive. </p>
<p>Astoundingly, when a seal intends to make a longer dive, the reduction in heart rate is greater and matches the intended dive duration quite well. Anticipatory redistribution of blood and control of heart rate demonstrate a simply incredible level of physiological control, which is used to prepare and manage their body to suit their anticipated behaviour. </p>
<p>This is quite an amazing concept. Seals can reduce their rate of oxygen consumption by as <a href="https://jeb.biologists.org/content/221/12/jeb182972.abstract">much as 70%</a> – a huge amount even compared to a hibernating bear, which can reduce the rate <a href="https://www.jstor.org/stable/pdf/30159983.pdf">by 25%</a>, or a sleeping human, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929498/">about 10%</a>. </p>
<p>As I mentioned, the difference between where some animals spend most of their time, and where they can breathe has had a wondrous impact on the physiological capacities of diving animals. </p>
<p>Non-invasive technology in the bio-medical world has allowed us to begin to understand just how wondrous their physiology really is. Away from the constraints of laboratory settings or simulated dives, seals can wear a small instrument, dive and behave as they like, and then tell us their physiological story. </p>
<p>So next time you jump into a swimming pool, consider the physiological changes your body is making to protect your brain against asphyxia, all automatically and without thought. Then imagine being able to control and regulate those changes – that’s what those amazing seals can do when you see them bobbing around the sea.</p><img src="https://counter.theconversation.com/content/121909/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris McKnight receives funding from NERC, BEIS and United States Office of Naval Research. </span></em></p>Diving animals are incredible athletes.Chris McKnight, Research Fellow, University of St AndrewsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1159742019-05-28T10:26:14Z2019-05-28T10:26:14ZHigh-tech fishing gear could help save critically endangered right whales<figure><img src="https://images.theconversation.com/files/276402/original/file-20190524-187176-1oipbcz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Only about 411 North Atlantic right whales exist, so every animal lost is a blow to the species' chance of surviving.</span> <span class="attribution"><span class="source">(c) Nick Hawkins</span></span></figcaption></figure><p>Many fish, marine mammals and seabirds that inhabit the world’s oceans are critically endangered, but few are as close to the brink as the North Atlantic right whale (<em>Eubalaena glacialis</em>). <a href="https://www.narwc.org/uploads/1/1/6/6/116623219/2018report_cardfinal.pdf">Only about 411 of these whales exist today</a>, and at their current rate of decline, they could become extinct within our lifetimes. </p>
<p>From 1980 through about 2010, conservation efforts focused mainly on protecting whales from being struck by ships. Federal regulations helped <a href="https://www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-ship-strikes-north-atlantic-right-whales">reduce vessel collisions</a> and supported a slight rebound in right whale numbers. </p>
<p>But at the same time, growing numbers of right whales died after becoming entangled in lobster and crab fishing gear, and the population has taken a significant downward turn. This may have happened because fishing ropes became stronger, and both whales and fishermen shifted their ranges so that areas of overlap increased. In research that is <a href="https://www.int-res.com/prepress/d03376.html">currently in press</a>, we show that 72% of diagnosed mortalities between 2010-2018 occurred due to entanglements. </p>
<p>This comes after a millennium of whaling that decimated the right whale population, reducing it from perhaps between <a href="https://doi.org/10.1111/cobi.12664">10,000 to 20,000</a> to a few hundred animals today. And entanglement deaths are <a href="http://dx.doi.org/10.1155/2012/230653">much more inhumane</a> than harpoons. A whaler’s explosive harpoon kills quickly, compared to months of drawn-out pain and debilitation caused by seemingly harmless fishing lines. We believe these deaths can be prevented by working with the trap fishing industries to adopt <a href="https://ropeless.org/">ropeless fishing gear</a> – but North Atlantic right whales are running out of time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/276168/original/file-20190523-187153-3andop.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="https://www.fisheries.noaa.gov/feature-story/team-reaches-nearly-unanimous-consensus-right-whale-survival-measures">NOAA</a></span>
</figcaption>
</figure>
<h2>Deadly encounters</h2>
<p>Whalers pursued right whales for centuries because this species swam relatively slowly and floated when dead, so it was easier to kill and retrieve than other whales. By the mid-20th century, scientists assumed they had been hunted to extinction. But in 1980, researchers from the New England Aquarium who were studying marine mammal distribution in the Bay of Fundy off eastern Canada were stunned when they <a href="https://www.canadianwhaleinstitute.ca/habitats">sighted 26 right whales</a>.</p>
<p>Conservation efforts led to the enactment of regulations that required commercial ships to <a href="https://www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-ship-strikes-north-atlantic-right-whales">slow down</a> in zones along the U.S. Atlantic coast where they were highly likely to encounter whales, reducing boat strikes. But this victory has been offset by rising numbers of entanglements.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=482&fit=crop&dpr=1 754w, https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=482&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/276403/original/file-20190524-187176-tvb9ag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=482&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An entangled right whale in Canada’s Gulf of St. Lawrence showing wraps over the blowhole and through the mouth, damaging baleen plates.</span>
<span class="attribution"><span class="source">(c) Nick Hawkins</span></span>
</figcaption>
</figure>
<p>Adult right whales can produce up to an estimated <a href="https://doi.org/10.1111/mms.12230">8,000 pounds of force</a> with a single stroke of their flukes. When they become tangled in fishing gear, they often break it and swim off trailing ropes and sometimes crab or lobster traps. </p>
<p>Lines and gear can wrap around a whale’s body, flukes, flippers and mouth. They impede swimming and feeding, and cause chronic infection, emaciation and damage to blubber, muscle and bone. Ultimately these injuries weaken the animal until it dies, <a href="https://doi.org/10.1093/icesjms/fsu008">which can take months to years</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=535&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=535&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=535&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=672&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=672&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275191/original/file-20190517-69186-k8kq9a.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=672&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fishing rope furrowed into the lip of Bayla, right whale #3911.</span>
<span class="attribution"><span class="source">Michael Moore, NMFS Permit 932-1905-00/MA-009526</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>One of us, <a href="https://scholar.google.com/citations?hl=en&user=DQ-fD1QAAAAJ">Michael Moore</a>, is trained as a veterinarian and has examined many entangled dead whales. Moore has seen fishing rope embedded inches deep into a whale’s lip, and a juvenile whale whose spine had been deformed by the strain of dragging fishing gear. Other animals had flippers nearly severed by swimming wrapped in inexorably constricting ropes. Entanglement injuries to right whales are the worst animal trauma Moore has seen in his career. </p>
<p>Even if whales are able to wriggle free and live, the extreme stress and energy demands of entanglement, along with inadequate nutrition, are thought to be <a href="https://doi.org/10.1002/ece3.2615">preventing females from getting pregnant</a> and contributing to record low calving rates in recent years. </p>
<h2>Solutions for whales and fishermen</h2>
<p>The greatest entanglement risk is from ropes that lobster and crab fishermen use to attach buoys to traps they set on the ocean floor. Humpback and minke whales and leatherback sea turtles, all of which are federally protected, also become entangled. </p>
<p>Conservationists are looking for ways to modify or eliminate these ropes.
Rock lobster fishermen in Australia already use <a href="https://www.youtube.com/watch?v=WeeieRr7sTw">pop-up buoys</a> that ascend when they receive sound signals from fishing boats. The buoys trail out ropes as they rise, which fishermen retrieve and use to pull up their traps. </p>
<p>Other technologies are <a href="https://www.wnpr.org/post/innovations-fishing-gear-could-change-lobster-industry-help-endangered-right-whale">in development</a>, including systems that <a href="https://ropeless.org/november-6th-2018-presentations/">acoustically identify traps on the seafloor</a> and mark them with “virtual buoys” on fishermen’s chart plotters, eliminating the need for surface buoys. Fishermen also routinely use a customized hook on the end of a rope to catch the line between traps and haul them to the surface when the buoy line goes missing.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ylQ5q7Ivs2o?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Trained rescuers disentangle an endangered North Atlantic right whale off Cumberland Island, Georgia, that was dragging more than 450 feet of rope and a 135-pound trap/pot.</span></figcaption>
</figure>
<p>Transitioning to ropeless technology will require a sea change in some of North America’s most valuable fisheries. The 2016 U.S. lobster catch was worth <a href="https://www.st.nmfs.noaa.gov/commercial-fisheries/commercial-landings/annual-landings/index">US$670 million</a>. Canadian fishermen landed <a href="http://www.dfo-mpo.gc.ca/stats/commercial/land-debarq/sea-maritimes/s2016av-eng.htm">CA$1.3 billion</a> worth of lobster and <a href="http://www.dfo-mpo.gc.ca/stats/commercial/land-debarq/sea-maritimes/s2016av-eng.htm">CA$590 million</a> worth of snow crab. </p>
<p>Just as no fisherman wants to catch a whale, researchers and conservationists don’t want to put fishermen out of business. In our view, ropeless technologies offer a genuine opportunity for whales and the fishing industry to co-exist if they can be made functional, affordable and safe to use. </p>
<p>Switching to ropeless gear is <a href="https://www.smithsonianmag.com/innovation/lobster-trap-aims-protect-endangered-whalesand-fishers-livelihoods-180971208/">unlikely to be cheap</a>. But as systems evolve and simplify, and production scales up, they will become more affordable. And government support could help fishermen make the shift. In Canada, the federal and New Brunswick provincial governments recently awarded CA$2 million to Canadian snow crab fishermen to <a href="https://www.cbc.ca/news/canada/new-brunswick/snow-crab-right-whale-fishing-gear-research-1.5143321">test two ropeless trap designs</a>.</p>
<p>Converting could save fishermen money in the long run. For example, California Dungeness crab fishermen closed their 2019 season three months ahead of schedule on April 15 to settle a lawsuit over whale entanglements, leaving crab they could have caught still in the water. Under the agreement, fishermen using ropeless gear will be <a href="https://www.nationalfisherman.com/west-coast-pacific/dungeness-drag/">exempt from future early closures</a>. </p>
<h2>A rebound is possible</h2>
<p>The <a href="https://www.fws.gov/endangered/laws-policies/">Endangered Species Act</a> and <a href="https://www.fws.gov/international/laws-treaties-agreements/us-conservation-laws/marine-mammal-protection-act.html">Marine Mammal Protection Act</a> require the U.S. government to conserve endangered species. In Congress, the pending <a href="https://www.congress.gov/bill/116th-congress/house-bill/1568/text?q=%7B%22search%22%3A%5B%22H.R.+3729%22%5D%7D">SAVE Right Whales Act of 2019</a> would provide $5 million annually for collaborative research into preventing mortalities caused by the fishing and shipping industries. And an advisory committee to the U.S. National Oceanic and Atmospheric Administration recently recommended <a href="https://www.fisheries.noaa.gov/feature-story/team-reaches-nearly-unanimous-consensus-right-whale-survival-measures">significant fishing protections</a>, focused primarily on reducing the number of ropes in the water column and the strength of the remaining lines. </p>
<p>Consumers can also help. Public outcry over dolphin bycatch in tuna fisheries spurred passage of the Marine Mammal Protection Act and led to <a href="https://swfsc.noaa.gov/textblock.aspx?Division=PRD&ParentMenuId=228&id=1408">dolphin-safe tuna labeling</a>, which ultimately reduced dolphin mortalities from half a million to about 1,000 animals annually. Choosing lobster and crab products <a href="https://doi.org/10.1093/icesjms/fsy194">caught without endangering whales</a> could accelerate a similar transition.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275194/original/file-20190517-69189-15eowzg.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Population trends in the North Atlantic and southern right whale species (estimates for North Atlantic species prior to 1990 are unavailable; southern estimates prior to 1990 on decadal scale). Illegal whaling caused a downturn in the southern species in the 1960s.</span>
<span class="attribution"><span class="source">Michael Moore; data from Pace et al., 2017, https://doi.org/10.1002/ece3.3406; North Atlantic Right Whale Consortium, https://www.narwc.org/uploads/1/1/6/6/116623219/2018report_cardfinal.pdf; and International Whaling Commission</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>North Atlantic right whales can still thrive if humans make it possible. The closely related southern right whale (<em>Eubalaena australis</em>), which has faced few human threats since the end of commercial whaling, has rebounded from just 300 animals in the early 20th century to an <a href="https://www.fisheries.noaa.gov/resource/document/southern-right-whale-eubalaena-australis-5-year-review-summary-and-evaluation">estimated 15,000 in 2010</a>. </p>
<p>There are real ways to save North Atlantic right whales. If they go extinct, it will be on this generation’s watch. </p>
<p><em>Editor’s note: This article was updated on May 28, 2019 to correct the number of North Atlantic right whale deaths in recent years that were caused by entanglements.</em></p><img src="https://counter.theconversation.com/content/115974/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Moore receives funding from the Worthington Foundation. </span></em></p><p class="fine-print"><em><span>Hannah Myers 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>North Atlantic right whales are headed toward a traumatic extinction, but could rebound if humans can get out of their way.Michael Moore, Senior Scientist, Woods Hole Oceanographic InstitutionHannah Myers, Guest Investigator, Woods Hole Oceanographic InstitutionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1163052019-04-30T12:31:57Z2019-04-30T12:31:57Z‘Russian spy whale’: the disturbing history of military marine mammals<p>Norwegian fishermen were <a href="https://www.dw.com/en/mystery-whale-found-near-norway-fuels-russian-navy-speculation/a-48536688">reportedly approached</a> recently by a beluga whale wearing a Russian harness, complete with GoPro camera holder, <a href="https://www.bbc.co.uk/news/world-europe-48090616">sparking speculation</a> that the animal had been trained to gather intelligence by the Russian Navy. While this theory has not been confirmed, it is entirely plausible: armed forces around the world have a long and disturbing history of exploiting marine mammals. </p>
<p>In the late 19th century, European militaries had <a href="https://books.google.co.uk/books/about/British_war_dogs.html?id=EKsPAwAAQBAJ&redir_esc=y">come to appreciate</a> that thoroughly-trained and well-handled dogs could perform useful military services, such as finding wounded soldiers on the battlefield and guarding military installations and outposts. Over the course of the 20th century, new roles were found for them: notably, <a href="https://www.uswardogs.org/war-dog-history/types-war-dogs/">detecting mines and explosives</a> during World War II. </p>
<p>Given the success achieved with dogs, it was perhaps inevitable that experiments would begin with other intelligent and trainable animals, including marine mammals. The earliest of these experiments took place during World War I, when Britain’s Royal Navy unsuccessfully attempted to train sea lions to locate German submarines. </p>
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<p>The early training – conducted at a facility on Lake Bala in Gwynedd, Wales – went well. But once the sea lions <a href="https://www.bbc.co.uk/news/uk-england-34666242">were released</a> into the open sea, they were generally found to be more interested in pursuing shoals of fish than U-boats – much to the frustration of the officers involved. </p>
<h2>Navy dolphins</h2>
<p>These efforts were revived by the United States and other nations during the Cold War, following the discovery that dolphins use <a href="https://uk.whales.org/whales-dolphins/how-do-dolphins-see-underwater-what-is-echolocation/">echolocation</a> to navigate underwater, emitting high frequency “clicking” sounds and listening for the echos that bounce back off their surroundings to locate and identify nearby objects. </p>
<p>A number of species of marine mammals, including dolphins, porpoises, sea lions, orcas, belugas and pilot whales, drew the attention of rival militaries. Not only do these animals possess extraordinary sensory and physical abilities, they can also change their behaviour – traits which meant they could be trained to perform much the same tasks at sea that dogs performed on land. </p>
<p>In coldly scientific language – and with little acknowledgement of the sophisticated intelligence and capacity for emotion expressed by these animals – one American manufacturer of military sonar equipment <a href="https://science.sciencemag.org/content/242/4885/1503">described them</a> as:</p>
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<p>Self-propelled marine vehicle[s], or platform[s]; with a built-in sonar sensor system suitable for detecting and classifying targets; and carrying an on-board computer … capable of being programmed for complex performance.</p>
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<p>The US Navy began its marine mammal programme in 1960, originally hoping to both improve the hydrodynamics of its torpedoes, and its ability to detect objects under water, by studying dolphins. Yet the scope of this programme appeared to expand rapidly. Dolphins were soon being trained to locate enemy mines and lost objects on the seabed. </p>
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<p>According to <a href="https://science.sciencemag.org/content/242/4885/1503/tab-pdf">American journalist David Morrison</a>, a team of dolphins was also deployed to South Vietnam to guard the US fleet anchored in Cam Ranh Bay against saboteurs in 1971. He also asserted that navy dolphins were transported to the Persian Gulf in 1987 to detect Iranian mines, and guard against enemy frogmen attempting to attack the US Navy’s floating command post. </p>
<h2>Protests for porpoises</h2>
<p>The use of these animals for military purposes has caused much controversy over the years. One of the more disturbing questions concerns what exactly these dolphins have been trained to do, should they encounter enemy saboteurs. In 1976, Michael Greenwood – a veteran of the Navy dolphin project – <a href="https://science.sciencemag.org/content/242/4885/1503">claimed that</a> dolphins assigned to the “swimmer nullification program” were equipped with syringes filled with carbon dioxide to kill intruders.</p>
<p>Despite vehement denials from the US Navy, such allegations have frequently resurfaced. Soviet Russia <a href="https://www.telegraph.co.uk/news/worldnews/europe/russia/12190205/Russias-killer-dolphins-seek-five-new-recruits-for-Crimea-programme.html">reportedly trained dolphins</a> in a similar manner at a facility in Crimea on the Black Sea. In 2000, <a href="http://news.bbc.co.uk/1/hi/world/middle_east/670551.stm">the BBC reported</a> that many of these dolphins were sold to Iran, following the collapse of the Soviet Union. The facility was re-opened by the Ukrainian Navy in 2012, but since the Russian annexation in 2014 has been <a href="https://www.theguardian.com/world/shortcuts/2014/jul/06/ukraine-combat-dolphins-russia-give-back">back in the hands</a> of the Russian Navy (although Ukrainian sources <a href="https://www.newsweek.com/ukraines-dolphin-army-dead-after-refusing-russian-military-takeover-says-kiev-92940">claim that</a> the dolphins have since starved, having refused to accept food from Russian handlers). </p>
<p>The treatment of these animals has been another matter of long-standing concern. David Morrison reported allegations of systematic mistreatment and poor standards of care for animals in the American programme, noting that it had become the focus of animal rights activism. According to <a href="https://science.sciencemag.org/content/242/4885/150">one report</a> in May 1987, “someone billing himself only as ‘Charly Tuna of RainBoWarriors’, cut the nets around four of the San Diego dolphin enclosures”.</p>
<p>Certainly, a great deal of the secrecy continues to surround the military use of sea mammals. And as Morrison observed as far back as 1989, this reflects “the fear of exciting public opposition to its efforts, opposition sparked by the great affinity that so many humans feel for these engaging creatures”. </p>
<p>More recently, animal rights organisation People for the Ethical Treatment of Animals (PETA) <a href="https://www.stripes.com/lifestyle/dolphins-help-navy-steer-clear-in-gulf-1.31649">has protested</a> the US deployment of dolphins to the Persian Gulf, stating: </p>
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<p>It is not ethical to put animals in harm’s way … War is a human endeavor, and while people and political parties may decide war is necessary, animals cannot.</p>
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<p>Whatever the exact origin of the (apparently friendly) beluga whale discovered in Norwegian waters, the story serves as a reminder that marine mammals are still commonly exploited for military purposes in the modern world. Their replacement by robotic submersibles seems, at the moment, a regrettably distant prospect.</p><img src="https://counter.theconversation.com/content/116305/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gervase Phillips 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>Russia isn’t the only nation suspected of training marine mammals for military use – the US, UK, and Ukraine have all done so in the past.Gervase Phillips, Principal Lecturer in History, Manchester Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.