{"id":1643,"date":"2010-11-16T10:27:43","date_gmt":"2010-11-15T23:27:43","guid":{"rendered":"https:\/\/scienceillustrated.com.au\/blog\/?p=1643"},"modified":"2010-11-16T10:27:43","modified_gmt":"2010-11-15T23:27:43","slug":"glowing-giants-of-the-ocean-swimming-with-whale-sharks","status":"publish","type":"post","link":"https:\/\/scienceillustrated.com.au\/blog\/nature\/glowing-giants-of-the-ocean-swimming-with-whale-sharks\/","title":{"rendered":"Glowing giants of the ocean: swimming with whale sharks"},"content":{"rendered":"
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Image: Juergen Freund\/Rolex Awards<\/p>\n<\/div>\n

Brad Norman has loved the ocean since he was a little boy, but after a surreal encounter with a feeding whale shark, he decided to dedicate his life to protecting the species. <\/strong><\/p>\n

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The Australian marine conservationist encountered the massive fish in 1995 while conducting master’s degree research at Murdoch University in Perth, WA. As it passed, the whale shark ignored Norman completely. “I was laughing into my snorkel,”\u009d he says, recalling “a mix of excitement and relief.”\u009d<\/p>\n

Soon he was diving with the species regularly, intrigued by how little researchers knew. These gentle giants, which can grow to 18 metres long during their lifetime, sport glowing white spots on their skin. Norman thought the markings might be used to identify individuals just as fingerprints identify humans.<\/p>\n

Before a 1986 review, Norman soon discovered, there were only 320 recorded observations of whale sharks. He realised that no one had any clue how many individuals there were in the world. And so, in 1999, Norman founded Ecocean, a database where he and other divers could pool their photos of the whale sharks and their markings. The idea was to find a way to identify individual sharks and to raise public awareness of the species.
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Brad Norman's Ecocean database. Image: Kurt Amsler\/Rolex Awards<\/p>\n<\/div>\n

Whale sharks are classified as vulnerable on the International Union for Conservation of Nature Red List because of past unregulated harpooning in Taiwan, India and the Philippines. The animals are now protected in the latter two countries, and protective regulations are pending in Taiwan. But conservation is hampered by how little scientists understand about the animals. For instance, whale shark reproduction is a mystery.<\/p>\n

They have never been seen mating because they spend most of their lives in waters too deep for observation. A rare insight surfaced in 1995, when a fisherman harpooned a pregnant female off the coast of Taiwan. Around 300 embryos of various sizes were found in her two uteruses, leading to suspicions that the species is ovoviviparous, meaning eggs hatch inside the female.<\/p>\n

The team forms In 2002, while diving in the Red Sea off the coast of Djibouti in northeastern Africa, Jason Holmberg, a technical writer, also fell in love. “As we were about to leave, someone said “\u02dcwhale shark,’ so I dove back in,”\u009d he recalls.<\/p>\n

The object of his affection was a two-and-a-half metre juvenile. He was particularly fascinated by the glowing spots on the shark’s skin. Holmberg wondered, like Norman had, if he could use the spots to identify individual fish.
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Image: Juergen Freund\/Nature PL. <\/p>\n<\/div>\n

“It was just an afterthought,”\u009d he says. “But the more I thought about it, the more curious I became.”\u009d He approached Zaven Arzoumanian, a research scientist at NASA Goddard Space Flight Centre, in the US, about adapting the Groth algorithm \u2014 used to map stars observed from the Hubble Space Telescope and other facilities \u2014 to identify spot patterns on whale sharks.<\/p>\n

To test the algorithm, the pair needed photos of the animals, and that’s how Holmberg and Arzoumanian found Norman and Ecocean. In 2005, the trio published proof that such an algorithm could, in fact, identify sharks.<\/p>\n

Today Ecocean contains more than 26,000 photos of over 2,100 whale sharks identified by the algorithm. These contributions, coming from a mix of researchers and amateur divers, have become essential to whale shark research. “By taking these photos, anyone can become a citizen scientist,”\u009d Norman says. Using Ecocean, which won Norman a National Geographic Emerging Explorers Award in 2008, people have recorded whale sharks off the coasts of 43 countries.<\/p>\n

Norman has also been able to attach digital “daily diaries”\u009d to individual sharks. These devices record the speed, depth and location of the animals, allowing Norman to track their activity. Through these recordings, he has learned that whale sharks, which swim slowly in shallow depths, climb and dive repeatedly and quickly while feeding at depths of up to 1,286 metres.
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Image: Juergen Freund\/Nature PL. <\/p>\n<\/div>\n

Because getting an exact count on the whale shark population is so difficult, Norman is still collecting data, and he hopes to gain a better understanding of the species’ health. Researchers speculate that whale sharks’ extensive migrations follow food pulses, or mass spawning of corals and other animals in tropical reefs near Australia, the Philippines, Mozambique, the Gulf of Mexico and the Gal\u00c3\u00a1pagos (as filter feeders, their diet consists of zooplankton, small fish and molluscs). If whale sharks stop visiting a particular area, it could be an important indicator of the health of their environment there, which could also affect other species.<\/p>\n

“I like to think of whale sharks as a canary in a coal mine for how our ecosystems are faring,”\u009d Norman says. In the end, it seems, falling in love with these giant fish means falling in love with the entire ocean.<\/p>\n","protected":false},"excerpt":{"rendered":"

Brad Norman has loved the ocean since he was a little boy, but after a surreal encounter with a feeding whale shark, he decided to dedicate his life to protecting the species.<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,56,45,32,6],"tags":[],"class_list":["post-1643","post","type-post","status-publish","format-standard","hentry","category-animals","category-conservation","category-environment","category-marine-biology","category-nature"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/1643"}],"collection":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/comments?post=1643"}],"version-history":[{"count":17,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/1643\/revisions"}],"predecessor-version":[{"id":1663,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/1643\/revisions\/1663"}],"wp:attachment":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/media?parent=1643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/categories?post=1643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/tags?post=1643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}