Whale shark diving discovered
whaleshark.jpg
Photo courtesy of Kurt
Amsler/Rolex Awards

The strange bounding underwater “flight” of the mightiest fish in the oceans has been revealed for the first time through a remarkable scientific collaboration.

This secret life of the whale shark, the world’s biggest fish, was recently disclosed in a scientific world-first by two Laureates of the Rolex Awards for Enterprise, Brad Norman, of Australia’s Murdoch University, and Professor Rory Wilson, of Swansea University, in the United Kingdom.

In the Indian Ocean, off Ningaloo, on Australia’s western coast, the team have equipped several whale sharks with a unique electronic device known as a “daily diary” that records in minute detail (eight times a second) the giant creatures’ every action – speed, depth, pitch, roll and heading, as well as every beat of the fish’s tail.

“For the first time we have an insight into what it is that these magnificent creatures get up to when they are out of sight of humans – and it isn’t what we expected,” said Norman, who received a Rolex Award in 2006 for his project employing “citizen scientists” worldwide to help study and protect whale sharks through an online global photo ID library, housed on the website http://www.whaleshark.org/.

“It’s a real Jekyll-and-Hyde existence,” said Wilson of the contrasting character of the shark revealed by his electronic wildlife monitor. The device is helping to lay bare the private lives of more than 50 different animal and bird species in the wild, providing information vital to their conservation, a project that won Wilson a Rolex Award, also in 2006.

Normally seen cruising slowly at the surface, the whale shark transforms into a dynamic monster in the deep, hurling itself into a swift, steep dive “like a fighter pilot”, soaring up, then down again, in a series of great bounds that have astonished the two scientists. “It is like the way a bird dives, then soars, using its momentum and gravity to conserve as much energy as possible. It flies like a bird – but, in this case, a bird as large as a bus!” Professor Wilson said. He believes such behaviour has never been observed in fish before.

The first insights into the world of the whale shark, one of the rarest and most mysterious creatures on earth, came at Ningaloo within minutes of equipping it with the daily diary, in late May this year. Clipped to its dorsal fin and retrieved by hand a few hours later, the diary reported every action second-by-second to the research team.

Whale sharks have been tagged and followed by satellite before, but their behaviour when deep below the surface has never been observed in such detail, Norman said. “It offers us an incredible window into how they live and what they do when out of our sight. This information will be vital in helping to protect this magnificent, but threatened species.”

In time, the two scientists hope, the diary will reveal how and where the whale sharks, which do not harm humans, feed and breed, enabling those localities to be protected from human impact such as hunting or pollution.

Norman and Wilson met for the first time at the 2006 presentation of the Rolex Awards for Enterprise, held in Singapore. As both of them are engaged in the scientific study of wildlife for conservation purposes, they saw an immediate chance to join forces to investigate this little-known species.

“The ECOCEAN Whale Shark Photo-identification Library will, in time, resolve into a broad picture of whale shark populations and movements worldwide.  The ‘daily diary’ tags provide us with some of the fine detail in that picture.  The Rolex Awards not only support both of these projects, but without their existence this particular collaboration may never have happened at all’ said Norman.

An initial sea trial in 2007 by Norman and shark specialist Adrian Gleiss proved it was feasible for a diver to attach an electronic diary to a whale shark’s fin and later retrieve it to download the mass of data collected by the device’s 13 channels.

In last month’s tests, diaries were attached to several sharks up to 8 metres in length off Ningaloo. Complete sets of data were then recovered, documenting every movement of the giant fish over several hours. The $3000 devices are designed to release manually or automatically from the shark and can be recovered by tracking it. However two were lost during the Ningaloo tests.

Whale shark research is a very costly science, involving several boats and aircraft to locate the sharks as they cruise the surface of the Indian Ocean. The work at Ningaloo would have been impossible without the generosity of Australian basketball champion Luc Longley who lent his 20-metre vessel for the research. The project is co-sponsored by the not-for-profit group ECOCEAN (http://www.ecocean.org/) and National Geographic.

To continue to investigate the secrets of the whale shark, the team will invite leading corporations and some schools around the world to “sponsor a whale shark”, name it and follow its adventures when tagged. The ultimate goal is to tag a shark for an entire year, revealing the critical habitats where it goes to feed and breed. As the sharks may swim thousands of kilometres per year, these places may lie far from where it is sighted, even in a different ocean.

So far Brad Norman’s ECOCEAN Library has logged over 15,000 photos of whale sharks taken by divers and holiday-makers worldwide. These represent around 1,400 individual sharks, some of which have been photographed as many as 50 times and are seen year after year in the same places. Reports are coming in from locations as far afield as Mexico, the Galapagos Islands and Mozambique, the Red Sea and the Philippines, Australia and Thailand in the first-ever survey of the global whale shark population. “It shows you can do valuable science with help from amateurs,” Norman said.

In time, the two scientists believe that a detailed knowledge of whale sharks and their habits will reveal new insights into the state of health of the oceans, on which all life ultimately depends.