Whale sharks, new research


This video is called Whale Sharks – Reef Life of the Andaman – Part 3.

From Wildlife Extra:

Whale shark ID identifies world hotspots

Donsol is Philippines Whale shark hotspot, reveals WWF, with at least 377 identified.

September 2012. High-tech satellite tags, waterproof cameras and hefty lungs are the tools of Dave David’s trade. As the head researcher of WWF’s Donsol-based whale shark photo-identification programme, Dave has spent the past six years holding his breath – literally – to swim with the world’s largest fish.

Weigh up to 10 tonnes

Strikingly-spotted whale sharks (Rhincodon typus) can grow longer than a passenger bus and weigh a whopping 10 tonnes. With unblinking golf ball-sized eyes, they wolf down wafting clouds of plankton and the occasional, unlucky small fish. Together with basking and megamouth sharks, they are one of just three planktivorous, or filter-feeding, sharks and have cruised the world’s seas for some 50 million years. Little is known of their habits, with fewer than 350 sightings recorded prior to the 1980s.

Through the support of WWF-Denmark, WWF-Philippines allied with Australia-based ECOCEAN, the Hubbs Sea World Research Institute (HSWRI) and Banco de Oro Unibank (BDO) to catalogue the country’s whale sharks. The partnership provides researchers with both population numbers and migratory data to guide conservation efforts not just for whale sharks – but for all migratory pelagic species.

Whale shark ID

Sporting waterproof digital cameras, trained WWF skin divers snap photos of a spot right above each shark’s pectoral fins, behind its gill slits. The photos are fed into a computer which uses a program to triangulate each shark’s unique spot configuration. Data is then uploaded to the web-based ECOCEAN library.

3822 whale sharks identified worldwide

Unless it is a new individual, the library shows researchers when and where the shark was last encountered. Since 2003, ECOCEAN has catalogued 3822 individual sharks from places as far as Mexico, Mozambique and the Galapagos Islands.

“Photo-identification is a non-invasive approach for identifying sharks,” explains David. “The library uses the whale shark’s distinct patterns, plus information on scars, sex and size to identify individuals.”

Philippines whale sharks

Since WWF-Philippines began implementing the programme in 2007, 458 individual whale sharks have been identified – 377 in Donsol, 54 in Cebu, 14 in Leyte and the rest in Bohol, Palawan, Albay and Batangas.

GPS tags

To complement the photo-identification drive, 29 whale sharks were affixed with detachable GPS satellite tags designed to pop to the surface after several months of data collation. Four sharks were tagged in May 2007, 10 more in May 2009 and 15 in April 2010.

Wide ranging, and deep

The results suggest that most tagged whale sharks keep to 200 kilometres of Donsol. Three however, swam east to the Philippine Sea, with one more swimming as far north as Taiwan. All spent most of their time below 50 metres, rarely rising to the surface to feed.

“The results suggest that whale sharks are highly-mobile, transient foragers which recognize no country or territorial boundary as their own. The distribution of whale sharks and other large filter-feeders also indicate the presence of plankton and the overall health of our oceans,” expounds David.

Whale shark hot spots – Ningaloo Reef, Mexico & Mozambique

For years, Donsol has been identified as a whale shark hotspot, hosting one of the largest aggregations of whale sharks on Earth. Other large aggregations include Ningaloo Reef in Australia with 808, Mexico with 812 and Mozambique with 624. Through continued research, Dave and other WWF volunteers hope to generate an accurate estimate of the country’s migratory and resident whale shark population.

“Long days at sea are worth it, considering the immense scientific, ecological and economic value that whale sharks bring people,” adds David. “Even after years of research, there’s still so much we have to discover – where they feed, mate and give birth. Our work continues, which is just as well because diving with these gentle giants is pure magic.”

After six years of swimming with the world’s largest fish, it seems that each shark encounter still leaves Dave breathless.

Whale sharks regulate their body temperature: here.

Whale sharks, a threatened species that can grow as big as a bus, have become so wildly popular with tourists that scientists, environmentalists and even eco-­tourism operators are calling for new limits on human contact: here.

Shark finning bans catching on! Way to go Vancouver! Here.

Today we moved closer to a complete ban on shark finning in the European Union: here.

Sharks are color blind, new research suggests, with the toothy predators likely forever seeing the world in black and white: here.

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5 thoughts on “Whale sharks, new research

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