tag:theconversation.com,2011:/us/topics/whale-sharks-4121/articlesWhale sharks – The Conversation2022-05-09T19:04:00Ztag:theconversation.com,2011:article/1825312022-05-09T19:04:00Z2022-05-09T19:04:00ZWhale sharks: how we discovered what’s killing so many of the world’s largest fish<figure><img src="https://images.theconversation.com/files/462007/original/file-20220509-21-isojmw.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1920%2C1279&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This whale shark bears a scar from colliding with a boat.</span> <span class="attribution"><span class="source">David Robinson</span>, <span class="license">Author provided</span></span></figcaption></figure><p><a href="https://unctad.org/webflyer/review-maritime-transport-2018#:%7E:text=Maritime%20transport%20is%20the%20backbone,upswing%20in%20the%20world%20economy.">Over 80%</a> of international trade is carried by sea. Much of what we use and consume everyday either has been or will be transported on huge vessels which plough the global ocean.</p>
<p>The courses these container vessels take are fixed shipping routes known as marine highways, which are not unlike motorways on land. These highways, which vessels travel back and forth, connect distant ports, often on opposite sides of vast oceans. </p>
<p>Marine highways can also cut across the movements and migratory routes of marine animals. Giant plankton-feeding whales and sharks are particularly vulnerable to being struck and killed by large vessels as they spend long periods near the surface. <a href="https://www.pnas.org/doi/full/10.1073/pnas.2117440119">Our new study</a> found that this threat may be a greater cause of death for the world’s largest fish, the whale shark, than anyone previously realised.</p>
<p>Whale sharks can reach lengths of up to 20 metres. Despite their robust appearance, their numbers have <a href="https://www.iucnredlist.org/species/19488/2365291">declined</a> by over 50% in the last 75 years. In 2016, they were added to the growing list of <a href="https://www.nature.com/articles/s41586-020-03173-9">endangered shark species</a>. </p>
<p>Unlike most other species of shark that roam the open ocean, intentional or accidental catches by <a href="https://www.nature.com/articles/s41586-019-1444-4">industrial fishing fleets</a> are not thought to be a leading cause of whale shark decline. This is because major whale shark fisheries have been closed down, and the species has been <a href="https://cites.org/eng/gallery/species/fish/whale_shark.html">protected by international trade bans</a> since 2003. Instead, several factors point to shipping being a leading, yet hidden cause of death.</p>
<p>Whale sharks spend a lot of their time cruising just below the ocean surface, often feeding on microscopic animals called zooplankton, which can put them in the direct path of a ship. If a large one collides with a whale shark, the shark probably stands little chance of survival. There is often no trace of these events because, if a fatal collision occurs, the body sinks, as whale sharks evolved from smaller, bottom-dwelling sharks and have retained their negative buoyancy. </p>
<p>This makes detecting and recording collisions difficult. Before now, the only evidence available was a sparse set of <a href="https://www.jstor.org/stable/1436507">eyewitness accounts</a>, <a href="https://progresohoy.com/noticias/aparece-tiburon-ballena-durante-el-atraque-de-un-buque-en-puerto-progreso-10114053/">news reports</a> and encounters with sharks <a href="https://academic.oup.com/conphys/article/9/1/coaa120/6102284">harbouring injuries</a> from collisions with smaller vessels.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A ventral view of a whale shark's back with a wide gouge." src="https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461807/original/file-20220506-24-so7g9t.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">Scars attest to how common ship strikes are likely to be.</span>
<span class="attribution"><span class="source">Simon Pierce</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We set out to uncover the hidden deaths of whale sharks by bringing together an international team of over 60 scientists from 18 countries. Our <a href="http://www.globalsharkmovement.org/">Global Shark Movement Project</a> satellite tracked almost 350 whale sharks by fitting them with electronic tags, mapping their positions across all major oceans in unprecedented detail. This revealed the most densely occupied regions, which were often in coastal areas where the species is known to congregate. </p>
<figure class="align-center ">
<img alt="A whale shark dorsal fin with electronic tag attached." src="https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461812/original/file-20220506-12-uespy0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Electronic tags allow scientists to track sharks using satellites.</span>
<span class="attribution"><span class="source">Mark Erdmann</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Striking overlap</h2>
<p>We compared these movements with a mandatory ship tracking system, which was initially developed to prevent ships colliding with each other. This helped us track global fleets of cargo, tanker, passenger, and fishing vessels – the types of large ships (heavier than 300 gross tons) capable of striking and killing a whale shark. We found that a staggering 92% of the horizontal space occupied by whale sharks and nearly 50% of their depth layers overlapped with the activities of these fleets.</p>
<p>We then developed state-of-the-art models to identify the collision risk within these overlapping areas and found that the Gulf of Mexico, Arabian Gulf and Red Sea posed the highest risk to whale sharks. These regions are home to some of the world’s busiest ports and sea passages, and because our estimated levels of risk correlated with known fatal collisions here, they appear to be some of the most dangerous places in the world for whale sharks to inhabit. </p>
<figure class="align-center ">
<img alt="A diver swimming alongside a whale shark." src="https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=428&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=428&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=428&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=538&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=538&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461810/original/file-20220506-22-gzihkm.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=538&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Coastal seas are among the most dangerous regions for whale sharks.</span>
<span class="attribution"><span class="source">Sofia Green</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Within high-risk areas, whale sharks regularly crossed vessel paths and passed close to ships that were travelling about ten times faster than they were swimming. This gave the sharks very little time to respond to an oncoming ship, and these close-range encounters may be happening more often than we have the capacity to monitor, potentially ending in fatal strikes.</p>
<p>Alarmingly, whale shark tag transmissions ended more often in busy shipping lanes than we expected. Even after accounting for the random technical failures of transmitters, we found 24% of tags stopped transmitting in busy shipping lanes, most likely due to whale sharks being lethally struck and sinking to the ocean floor.</p>
<p>We may even have recorded whale sharks dying due to collisions. Some of the tags record depth as well as location and showed sharks moving into shipping lanes but then sinking slowly to the seafloor hundreds of metres below – the smoking gun for a lethal ship strike.</p>
<figure class="align-center ">
<img alt="A large container vessel on the horizon." src="https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461813/original/file-20220506-12-gp2c6a.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">Global shipping routes are an underappreciated threat to marine life.</span>
<span class="attribution"><span class="source">Simon Pierce</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>En route to danger</h2>
<p>The substantial threat to whale sharks uncovered by our study makes a strong case for urgent protection measures. At present, there are no international regulations to protect whale sharks from ship collisions. In light of our study, this species faces an uncertain future if action is not taken soon. </p>
<p>As a first step to address this crisis, the International Maritime Organization (IMO) could develop a global reporting scheme that consolidates records of ship-wildlife collisions for whale sharks and other threatened species. Such a network would help regional authorities implement protection measures by providing evidence of where collisions are happening. </p>
<p>Initiatives to lower the risk of ship strikes could emulate measures to protect <a href="https://whalesafe.com/">whales from collisions</a>, such as IMO regulations that require ships to slow down or navigate more carefully. Our study can help by identifying high-risk areas where these measures could be trialled.</p>
<p>Rapid action may be the only way to prevent whale shark numbers from sinking further towards extinction.</p><img src="https://counter.theconversation.com/content/182531/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Freya Womersley receives funding from the Natural Environment Research Council (NERC) through a University of Southampton INSPIRE DTP PhD Studentship. She is affiliated with the Marine Biological Association (MBA) in Plymouth, UK and the Global Shark Movement Project, which is based at the MBA.</span></em></p><p class="fine-print"><em><span>David Sims receives funding from the Natural Environment Research Council (NERC), the European Research Council (ERC), and the Gordon and Betty Moore Foundation. He is affiliated with the Marine Biological Association (MBA) in Plymouth, UK, and the Global Shark Movement Project, which is based at the MBA.</span></em></p>Plankton-eating sharks are struggling to navigate crowded ocean highways, a new study suggests.Freya Womersley, PhD Candidate in Marine Ecology, University of SouthamptonDavid Sims, Professor of Marine Ecology, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1537672021-01-22T16:45:00Z2021-01-22T16:45:00ZWhale sharks: boat strikes in protected areas could be harming the animals’ development<figure><img src="https://images.theconversation.com/files/380032/original/file-20210121-13-tbc9g7.jpg?ixlib=rb-1.1.0&rect=144%2C137%2C4407%2C2876&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Whale sharks are the ocean's biggest fish.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/whale-shark-blue-water-1192961899">jjsupasit srisawthsak/shutterstock.com</a></span></figcaption></figure><p>The <a href="https://www.publish.csiro.au/?paper=MF17393">biggest fish in the ocean</a>, whale sharks, are incredible animals. They can reach lengths of over 18 metres and weigh more than 19,000kg. Each shark has a unique pattern of spots on its body, like a fingerprint.</p>
<p>The number of whale sharks in our oceans has been in decline for years and as a result the species is endangered. Recently, efforts to conserve the animals through <a href="https://www.cambridge.org/core/journals/oryx/article/can-ecotourism-change-community-attitudes-towards-conservation/7B83C9848D8872256B74116E380FC2AF">ecotourism</a> have been severely impacted by the pandemic.</p>
<p>Marine protected areas (MPAs), where human activities like fishing are restricted, are an important tool when it comes to the global conservation of many animals in the sea, including whale sharks. But <a href="https://doi.org/10.1038/s41598-020-79101-8">our new study</a> shows these areas might not be the safe haven we once thought they were.</p>
<p>We looked into how long whale sharks spend within an MPA and how this is impacted by injuries. We found injuries from boat strikes delayed the animals’ development, making them spend longer in the area before going out into the wider ocean. This is the first study to link human activity with a change in whale sharks’ life stages. Our work poses difficult questions for the regulation of boat traffic and wildlife tourism within protected areas.</p>
<figure class="align-center ">
<img alt="A swimmer next to a whale shark." src="https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=332&fit=crop&dpr=1 600w, https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=332&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=332&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=417&fit=crop&dpr=1 754w, https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=417&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/380030/original/file-20210121-19-rfdfvi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=417&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Swimming with whale sharks is popular for tourists.</span>
<span class="attribution"><span class="source">Gregor Kervina</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Ecotourism</h2>
<p>In the past, whale sharks were easy targets for fisheries, who harvested their meat and oil from their fatty livers. International demand for shark fins means the fish are still hunted in many areas of the world. To conserve whale sharks, charities and activists have aimed to shift the focus away from hunting and towards ecotourism.</p>
<p>Despite their size, whale sharks are filter feeders, with throats incapable of swallowing anything larger than a thumb-sized sprat. The slow moving grace of the creatures, and their seeming indifference to the presence of humans, ensures their position on the bucket lists of many snorkelers, divers and swimmers.</p>
<p>Nowhere is this more evident than in the South Ari Atoll MPA (Sampa) in the Maldives. There, whale shark-related tourism was a cornerstone of the economy prior to the pandemic, bringing in <a href="https://peerj.com/articles/515/">$9.4 million</a> (£6.9m) a year. Unfortunately, anecdotal reports suggest loss of income from tourism in 2020 has seen an upsurge in <a href="https://www.instagram.com/p/CJ5zL6aBqNC/?igshid=1a9mjr0kovru">illegal hunting and finning</a>, threatening conservation efforts.</p>
<h2>Sampa</h2>
<p>The waters in Sampa are one of very few places in the world where the usually transient whale sharks take up semi-permanent residence. Most of the sharks in the area are immature males, so the area is referred to as a <a href="http://www.int-res.com/abstracts/meps/v337/p287-297/">developmental habitat</a>.</p>
<p>Places like Sampa give young sharks somewhere to build up strength before moving off into the wider ocean. For marine biologists and conservationists, this provides a rare opportunity to study the behaviour of individual animals for long periods of time.</p>
<p>Much of whale shark ecology remains a mystery. We are yet to identify where they give birth to their young, or even <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.576343/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field=&journalName=Frontiers_in_Marine_Science&id=576343">confirm where they mate</a>, which is a roadblock for conservation. Previously, it was assumed tourist attention had very little impact on sharks. But in recent years, mounting evidence has emerged, suggesting human presence is <a href="https://www.cambridge.org/core/journals/oryx/article/monitoring-the-effects-of-tourism-on-whale-shark-rhincodon-typus-behaviour-in-mozambique/1B5F671AD63D13BC4F073C7B8A6A893B">altering their behaviour</a>.</p>
<p>Our study is based on 15 years of dedicated surveying by the <a href="https://maldiveswhalesharkresearch.org/">Maldives Whale Shark Research Programme</a> (MWSRP), along with citizen science data. We estimated whale shark abundance in Sampa and found it has been decreasing steadily each year, falling from 48 sharks in 2014 to 32 in 2019. The overall decline in whale shark abundance in Sampa falls in line with <a href="https://www.iucn.org/news/secretariat/201607/whale-sharks-winghead-sharks-and-bornean-orangutans-slide-towards-extinction">global trends</a> for the endangered species.</p>
<figure class="align-center ">
<img alt="A whale shark with injuries." src="https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/380029/original/file-20210121-13-k7ei2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">More than half of the whale sharks studied had been injured by boats.</span>
<span class="attribution"><span class="source">MWSRP</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Boat strikes</h2>
<p>Worryingly, we found that 61% of sharks in the study had severe injuries. While some sharks arrive in the MPA with injuries, others acquire them during their residency. We did not directly observe boat strikes happening within the MPA. However, based on the modelling, we can say sharks likely acquired injuries during their residency in the area.</p>
<p>We modelled how long whale sharks were staying in the area, and how this related to injuries. For the first time, we found sharks with severe injuries spend longer in the developmental habitat than those without. Our study suggests injured sharks remain in the area as they have access to food and warm water which supports their recovery. </p>
<p>Unfortunately, human activities within the developmental habitat mean sharks continue to acquire injuries while they are there. Whale sharks spend a lot of time cruising just below the surface of the ocean, feeding on plankton and small animals. This puts them right in the path of boats. Most injuries we observed were clearly caused by humans, ranging from abrasions from hulls to fins cut off by propellers. The majority of boat traffic within Sampa is related to tourism, with vessels carrying snorkelers and divers.</p>
<p>Sharks are amazing <a href="https://pubmed.ncbi.nlm.nih.gov/27293741/">healers</a>, given time they can recover from severe injuries. However, even if injuries don’t kill them, they alter their life history.</p>
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Read more:
<a href="https://theconversation.com/whale-sharks-gather-at-a-few-specific-locations-around-the-world-now-we-know-why-98502">Whale sharks gather at a few specific locations around the world – now we know why</a>
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<p>Whale sharks <a href="https://doi.org/10.1007/s00227-005-0153-8">journey across vast distances</a> during their long lifetimes, which can see them reach ages of <a href="https://www.publish.csiro.au/MF/MF17393">more than 130 years</a>. This means they often cross political jurisdictions and are subject to various levels of exploitation.</p>
<p>To ensure sharks have a safe space to recover, we suggest changes to the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0165783606004061?casa_token=jv__k1q9nYUAAAAA:vRu7oiAXke_sD0l-Ei3Key0lejmWosxtlhmnF_jAysUBuq4rg5csz3AiqsbYRDE4dkh77CSDvKQ">management to the MPA</a>. Speed limit zones would help prevent further injuries. A transition of the current voluntary guidelines for tourist encounters to enforceable regulations would also help safeguard the animals.</p>
<p>The survival and health of juvenile animals is paramount to the future of the species. Protecting them at the <a href="https://doi.org/10.1111/j.1755-263X.2008.00046.x">formative part of their life cycle</a> can have a global impact.</p><img src="https://counter.theconversation.com/content/153767/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daire Carroll is affiliated with MWSRP. </span></em></p><p class="fine-print"><em><span>Jessica Harvey-Carroll is affiliated with MWSRP. </span></em></p>This is the first study to link human activity with a change in whale sharks’ life stages.Daire Carroll, PhD Researcher in Microbial Ecology, University of WarwickJessica Harvey-Carroll, PhD Researcher, University of St AndrewsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1354292020-04-06T20:06:21Z2020-04-06T20:06:21ZThe mushroom cloud’s silver lining: how the Cold War is helping the biggest fish in the sea<figure><img src="https://images.theconversation.com/files/325563/original/file-20200406-196131-1rarj4v.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5121%2C2683&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">United States Department of Defense/Wikimedia</span></span></figcaption></figure><p>It might surprise you to learn that nuclear bomb tests during the Cold War are now helping conserve whale sharks, the largest living fish. </p>
<p>Growing up to 18 metres – longer than the average bus – whale sharks live in all tropical oceans. In Australia, they are found off tropical coasts in the north, particularly in Western Australia.</p>
<p>Whale sharks face a number of threats. Globally they are <a href="https://www.iucnredlist.org/species/19488/2365291">listed as endangered</a>, and their numbers continue to decline.</p>
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Read more:
<a href="https://theconversation.com/whale-shark-mugshots-reveal-teenage-males-hang-around-was-coast-68823">Whale shark mugshots reveal teenage males hang around WA's coast</a>
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<p>Until recently, key information about the life history of whale sharks was missing, which prevented informed choices about how they were managed. In particular, scientists were not able to accurately assess their age and growth patterns.</p>
<p>Our research, <a href="https://www.frontiersin.org/articles/10.3389/fmars.2020.00188/abstract">published today</a> in Frontiers in Marine Science, changes that. We examined the skeleton of whale sharks, using carbon from Cold War atomic bomb testing as a “time stamp” to reveal their true age. The findings will help protect these beautiful animals into the future.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325401/original/file-20200404-74279-lm9pjw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Until now, it’s been difficult to assess the age of whale sharks.</span>
<span class="attribution"><span class="source">Wayne Osborn</span></span>
</figcaption>
</figure>
<h2>Gentle giants</h2>
<p>Whale sharks are placid “filter feeders”, which basically means they eat by opening their massive mouths and straining small fish and plankton that pass through the gills.</p>
<p>They are covered in a pattern of stripes and spots that provide camouflage as they bask at the surface. Whale sharks’ gentle nature and striking appearance has made them a drawcard for tourists who pay to snorkel or dive with the animals. </p>
<p>Whale shark ecotourism is big business. At Ningaloo Reef off Western Australia, the industry is worth an <a href="https://link.springer.com/article/10.1007/s11160-017-9486-x">estimated A$12.5 million per year</a>. </p>
<p>The industry is also valuable for small island nations such as the Maldives and developing countries including the Philippines and Indonesia. It has lifted thousands of villagers from poverty and provided an impetus for governments to protect whale sharks.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/poor-filipino-fishermen-are-making-millions-protecting-whale-sharks-122451">Poor Filipino fishermen are making millions protecting whale sharks</a>
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<p>But all is not plain sailing for these animals. In some parts of the world they are <a href="https://www.abc.net.au/news/2014-02-05/an-hundreds-of-sharks-killed-annually-in-illegal-trade-in-china/5239568">hunted</a> for their fins, meat, oil and skin. The flesh resembles tofu when cooked, and is a popular menu item in parts of Asia, particularly China. </p>
<p>When shipping lanes are established near whale shark habitat, the animals are frequently struck by vessels and either die or suffer <a href="https://www.sciencedaily.com/releases/2020/01/200123152549.htm">propeller injuries</a> such as fin amputation. Their habit of <a href="https://theconversation.com/whale-sharks-swim-near-surface-to-keep-warm-10249">basking at the surface of the ocean</a> during the day puts whale sharks at particular risk of ship strike.</p>
<p>This combined with other threats – such as warming sea surface temperatures <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.12343">due to climate change</a> – has created an uncertain future for these charismatic and valuable animals.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325564/original/file-20200406-74216-111wnoc.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 whale shark carcass on the shore of Teluk Betung beach in West Sumatra, Indonesia, last year. The animal is considered endangered.</span>
<span class="attribution"><span class="source">RAJO BATUAH/EPA</span></span>
</figcaption>
</figure>
<h2>The silver lining on the mushroom cloud</h2>
<p>Just how vulnerable whale shark populations are to these threats is not clear. Growth rates of fish species – or how many years they take to reach a certain size - determine their resilience, and how fast populations are likely to recover if severely damaged.</p>
<p>But determining the age of whale sharks has, to date, been very difficult. Their vertebrae feature distinct bands, similar to the rings of a tree trunk, which increase in number as the animal grows older. But the bands could not conclusively be used to determine age because some scientists believed a ring formed every year, but others suggested one formed every six months.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=537&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=537&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=537&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=675&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=675&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325566/original/file-20200406-79380-rhoqqa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=675&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">Cross section of a whale shark vertebra from Pakistan, showing 50 growth bands.</span>
<span class="attribution"><span class="source">Paul Fanning/ Pakistan node of the UN Food and Agricultural Organisation</span></span>
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</figure>
<p>To settle the debate, we turned to the radioactive legacy of the Cold War’s nuclear arms race - specifically, carbon-14.</p>
<p>Carbon-14 is a naturally occurring radioactive element. But in the 1950s and early 1960s, nuclear weapons tests by the US, Soviet Union, Great Britain, France and China released enormous amounts of carbon-14 into the air.</p>
<p>It travelled into the world’s oceans, and into every living organism on the planet – including the skeletons and shells of animals.</p>
<p>We analysed the vertebrae of two whale sharks collected many years ago in Taiwan and Pakistan. By counting back from the peak carbon-14 level, we concluded the rings were formed once per year. This meant that for the first time, the age and growth rate of a whale shark could accurately be determined; a 10-metre shark was 50 years old. </p>
<p>We know whale sharks can grow to almost twice the length of the animals we analysed, and have been estimated to live as long as <a href="https://link.springer.com/content/pdf/10.1023/A:1026564707027.pdf">100 years</a>. The results of our study makes that prediction now seem more likely. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325565/original/file-20200406-74279-1876l9i.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">Whale sharks can live as long as 100 years.</span>
<span class="attribution"><span class="source">Wayne Osborn</span></span>
</figcaption>
</figure>
<h2>What does this mean for whale sharks?</h2>
<p>Slow-growing species with long lifespans are typically very susceptible to threats such as fishing. This is because it takes many years for animals to reach reproduction age, and the rate at which individuals are replaced is very slow. </p>
<p>Our study explains why fisheries targeting whale sharks almost immediately collapse: the species is not built to cope with the added pressures of human harvests.</p>
<p>Whale sharks populations take a very long time to recover from over-harvesting. Governments and management agencies must work together to ensure this iconic animal persists in tropical oceans - for both the future of the species, and the many communities whose livelihoods depend on whale shark ecotourism.</p>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/whale-sharks-swim-near-surface-to-keep-warm-10249">Whale sharks swim near surface to keep warm</a>
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</p>
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<img src="https://counter.theconversation.com/content/135429/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Meekan receives funding from Santos Energy and the Save Our Seas Foundation.</span></em></p>The findings will help determine the age of whale sharks, protecting the endangered animals into the future.Mark Meekan, Senior Principal Research Scientist, Australian Institute of Marine ScienceLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1224512019-08-27T07:03:57Z2019-08-27T07:03:57ZPoor Filipino fishermen are making millions protecting whale sharks<figure><img src="https://images.theconversation.com/files/289569/original/file-20190827-184240-2mzkhd.jpg?ixlib=rb-1.1.0&rect=32%2C0%2C3600%2C2392&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Whale sharks at Oslob are now part of a new ecotourism industry.</span> <span class="attribution"><span class="source">Wayne Jones</span>, <span class="license">Author provided</span></span></figcaption></figure><p>A group of the world’s poorest fishermen are protecting <a href="https://www.iucnredlist.org/">endangered</a> whale sharks from being <a href="https://www.jstor.org/stable/42633292?seq=1#page_scan_tab_contents">finned alive</a> at Oslob in the Philippines. </p>
<p>The fishermen have stopped fishing and turned to tourism, feeding whale sharks tiny amounts of krill to draw them closer to shore so tourists can snorkel or dive with them. </p>
<p>Oslob is the most reliable place in the world to swim with the massive fish. In calm waters, they come within 200m of the shore, and hundreds of thousands of tourists flock to see them. Former fishermen have gone from earning just a US$1.40 a day on average, to US$62 a day.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whale-sharks-gather-at-a-few-specific-locations-around-the-world-now-we-know-why-98502">Whale sharks gather at a few specific locations around the world – now we know why</a>
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<hr>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0964569118303909">research</a> involved investigating what effect the whale shark tourism has had on livelihoods and destructive fishing in the area. We found that Oslob is one of the world’s most surprising and successful alternative livelihood and conservation projects. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289553/original/file-20190827-8889-v2jpcb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A drone shot of whale shark tourism, about 100 metres from shore. The small boats with one person are feeders. The longer boats are for the tourists swimming with face masks to see the whale sharks.</span>
<span class="attribution"><span class="source">Luigi Borromeo</span></span>
</figcaption>
</figure>
<h2>Destructive fishing</h2>
<p>Illegal and destructive fishing, involving dynamite, cyanide, fish traps and drift gill nets, threatens endangered species and coral reefs throughout the Philippines.</p>
<p>Much of the rapidly growing population depend on fish as a key source of protein, and selling fish is an important part of many people’s income. As well as boats fishing illegally close to shore at night, fishermen use compressors and spears to dive for stingray, parrotfish and octopus. Even the smallest fish and crabs are taken. Catch is sold to tourist restaurants.</p>
<p>Despite legislation to protect whale sharks, they are still poached and finned alive, and caught as bycatch in trawl fisheries. “We have laws to protect whale sharks but they are still killed and slaughtered,” said the mayor of Oslob. </p>
<p>“Finning” is a particularly cruel practice: sharks’ fins are cut off and the shark is thrown back into the ocean, often alive, to die of suffocation. Fins are sold illegally to Taiwan for distribution in Southeast Asia. Big fins are highly prized for display outside shops and restaurants that sell shark fin products.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289572/original/file-20190827-184248-1n5wj63.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">Whale sharks come close to the coast to feed on krill.</span>
<span class="attribution"><span class="source">Andre Snoopy Montenegro</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To protect the whale sharks on which people’s new tourism-based livelihoods depend, Oslob pays for sea patrols by volunteer sea wardens <a href="http://philippinenavy.tripod.com/bantay.html">Bantay Dagat</a>. Funding is also provided to manage five marine reserves and enforce fishery laws to stop destructive fishing along the 42km coastline. Villagers patrol the shore. “The enforcement of laws is very strict now,” said fisherman Bobong Lagaiho. </p>
<p>Destructive fishing has declined. Fish stocks and catch have increased and species such as mackerel are being caught for the first time in Tan-awan, the marine reserve where the whale sharks congregate.</p>
<p>The decline in destructive fishing, which in the Philippines can involve dynamite and cyanide, has also meant there are more non-endangered fish species for other fishers to catch.</p>
<h2>Strong profits means strong conservation</h2>
<p>The project in Oslob was designed by fishermen to provide an alternative to fishing at a time when they couldn’t catch enough to feed their families three meals a day, educate their children, or build houses strong enough to withstand typhoons. </p>
<p>“Now, our daughters go to school and we have concrete houses, so if there’s a typhoon we are no longer afraid. We are happy. We can treat our children to good food, unlike before,” said Carissa Jumaud, a fisherman’s wife.</p>
<p>Creating new forms of income is an essential part of reducing destructive fishing and overfishing in less developed countries. Conservation donors have invested hundreds of millions of dollars in various projects, however research has found they <a href="https://environmentalevidencejournal.biomedcentral.com/articles/10.1186/s13750-015-0048-1">rarely work once funding and technical expertise are withdrawn</a> and can even have negative effects. In one example, <a href="https://dukespace.lib.duke.edu/dspace/bitstream/handle/10161/6822/Brock_MastersProject.pdf?sequence=1">micro-loans</a> to fishermen in Indonesia, designed to finance new businesses, were used instead to buy more fishing equipment.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289555/original/file-20190827-8889-qs7f8a.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Former fisherman Jesson Jumaud with his daughter Kheny May, who now goes to school. The profits of whale shark tourism mean they now have a brick house, and Jesson was able to buy a motor bike. He can feed their family three times a day with good food.</span>
<span class="attribution"><span class="source">Judi Lowe</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In contrast, Oslob earned US$18.4 million from ticket sales between 2012 and 2016, with 751,046 visitors. Fishermen went from earning around US$512 a year to, on average, US$22,699 each.</p>
<p>Now, they only fish in their spare time. These incredible results are the driving force behind protecting whale sharks and coral reefs. “Once you protect our whale sharks, it follows that we an have obligation to protect our coral reefs because whale sharks are dependant on them,” said the mayor.</p>
<p>Feeding whale sharks is controversial, and some western environmentalists have lobbied to shut Oslob down. However, a <a href="https://www.sciencedirect.com/science/article/pii/S026151771930032">recent review of various studies on Oslob</a> found there is little robust evidence that feeding small amount of krill harms the whale sharks or significantly changes their behaviour. </p>
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Read more:
<a href="https://theconversation.com/are-sharks-being-attacked-by-killer-whales-off-cape-towns-coast-110373">Are sharks being attacked by killer whales off Cape Town's coast?</a>
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<p>Oslob is that rare thing that conservation donors strive to achieve – a sustainable livelihoods project that actually <a href="https://www.sciencedirect.com/science/article/pii/S0964569118303909">changes the behaviour</a> of fishermen. Their work now protects whale sharks, reduces reliance on fishing for income, reduces destructive fishing, and increases fish stocks – all while lifting fishermen and their families out of poverty. Oslob is a win-win for fishermen, whale sharks and coral reefs.</p><img src="https://counter.theconversation.com/content/122451/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Judi Lowe 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>Former fishermen in the Philippines are lifting their families out of poverty through whale shark tourism.Judi Lowe, PhD Candidate, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/688232016-11-16T01:17:59Z2016-11-16T01:17:59ZWhale shark mugshots reveal teenage males hang around WA’s coast<figure><img src="https://images.theconversation.com/files/145970/original/image-20161115-30742-12hsg6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A researcher taking a photo-identification shot of a whale shark</span> <span class="attribution"><span class="source">(C) Peter Verhoog, Dutch Shark Society</span></span></figcaption></figure><p>Every year in March juvenile male whale sharks arrive at Ningaloo Reef, Western Australia, supporting a thriving ecotourism industry. But where do they go in July once they leave this meeting site?</p>
<p>Results from <a href="http://rsos.royalsocietypublishing.org/content/3/11/160455">our study</a>, published today in Royal Society Open Science, suggests they don’t go far. By comparing identification photos of whale sharks in a collaborative study across the Indian Ocean, we have found that juvenile males appear to return to the same sites year after year. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145969/original/image-20161115-30777-7jijnl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Researchers swim alongside a whale shark at Ningaloo Reef.</span>
<span class="attribution"><span class="source">Peter Verhoog, Dutch Shark Society</span></span>
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</figure>
<h2>The biggest fish in the sea</h2>
<p>Whale sharks are the largest fish in the sea, reaching sizes of more than 12 metres. These peaceful giants are filter-feeders, mostly eating tiny crustaceans, fish eggs and small fish that they sieve from the water using plates on their gills. </p>
<p>They reach maturity when they are around 8m long, but it can take them up to 30 years to reach this size. Because of this slow growth rate and their vulnerability to ship strikes and bycatch in fisheries worldwide, the status of whale sharks has recently been upgraded to <a href="http://www.iucnredlist.org/details/19488/0">Endangered by the IUCN Red List</a>. If conservation strategies for the species are to be successful, we need to know where these animals are going and the places they visit on their migrations. </p>
<p>Whale sharks form aggregations off tropical coasts around the world that are a response to seasonal pulses in the abundance of their food. In the Indian Ocean, these occur at Ningaloo Reef as well as in the Maldives, off the coast of Mozambique, and in the Seychelles. </p>
<p>Because these sharks are docile and spectacular, aggregations are the target of ecotourism industries in each of these localities. To date, genetic studies have suggested the sharks in all these different aggregations form one population, implying that animals are moving between these sites. However, no direct evidence for these movements exists. </p>
<h2>Photo-identification</h2>
<p>Just like a fingerprint, we can identify whale sharks from their unique spot and stripe patterns. By comparing photos of a standard area on the body of a whale sharks among both years and locations, we can then determine if an individual is moving to a new location, or returning in multiple years. This method is called photo-identification. </p>
<p>Using the large and expanding database of whale shark photos taken by ecotourists, tour operators and researchers in the Indian Ocean, we used this method to look at movement patterns. Using a semi-automated matching program, we compared a database of over 6,000 images of whale sharks across the Indian Ocean. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145972/original/image-20161115-30787-15zghl4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The area of spot and stripe patterns on a whale shark used in photo-identification.</span>
</figcaption>
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<h2>What did we find?</h2>
<p>From our comparison we were able to identify about 1,000 individual whale sharks, of which 35% were seen again at the same site in more than one year, and none of which were found to move across the Indian Ocean. One shark was tracked between Mozambique and the Seychelles, suggesting that regional links do occur, however on a larger scale, populations appear to be isolated and distinct. </p>
<p>Within these aggregations, juvenile males are returning on a regular basis. At Ningaloo, juvenile males photographed in 1992 have so far been seen up to 19 years later, with many sightings in between. In more recent years as the photograph databases have expanded with the tourism industries, we have seen some sharks returning in up to six consecutive years.</p>
<p>Females and adult males were rarely spotted at these sites, so it is possible that they aren’t homebodies like the young males. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=498&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=498&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=498&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=626&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=626&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145973/original/image-20161115-30742-1cys4rw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=626&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A sample of the identification photos from the database.</span>
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<h2>Good news for whale sharks</h2>
<p>The absence of large-scale movements here is good news for the endangered whale shark. Conservation and management efforts can focus on smaller areas, and a lesser degree of cross-jurisidictional management will be required than if we found cross-ocean movements to be commonplace. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145971/original/image-20161115-30749-1003bqr.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">Researchers from the Australian Institute of Marine Science get ready to photograph a whale shark.</span>
<span class="attribution"><span class="source">Peter Verhoog/Dutch Shark Society</span></span>
</figcaption>
</figure>
<p>However, we need to improve our understanding of the regional movements of these animals. A computer simulation analysis study of our data indicated we need to increase the number of study sites and photos taken to get an estimate of their migration patterns at larger scales.</p><img src="https://counter.theconversation.com/content/68823/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Meekan receives funding from Quadrant Energy Ltd and the Save Our Seas Foundation for this work. </span></em></p><p class="fine-print"><em><span>Sammy Andrzejaczek 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>How you tell one whale shark from another? Spots and stripes.Sammy Andrzejaczek, PhD candidate, The UWA Oceans Institute & School of Environmental Systems Engineering, The University of Western AustraliaMark Meekan, Principal Research Scientist, Australian Institute of Marine ScienceLicensed as Creative Commons – attribution, no derivatives.