Bus under water
Driven by a love of the sea and its largest fish, the elusive whale shark, Australian naturalist Brad Norman has created a worldwide photo-identification system which enables ordinary people to assist in its conservation. JULIAN CRIBB reports
BEFORE the swimmer’s eyes, glowing flecks shine like stars eerily transposed into the depths of the sea.
Through a blue-dark veil of water, a huge shape gradually resolves itself, rising slowly and majestically to the surface.
After hundreds of sightings, Brad Norman’s blood still thrills as the great, spotted whale shark comes into view, gliding effortlessly forward, its pale, metre-wide mouth agape to scoop up thousands of litres of proteinrich sea water.
‘‘When they are down deep, they resemble a starfield under water,’’ he says. ‘‘As you swim above, the shark’s body seems to disappear and its white spots light up like stars in the night sky. It’s an aweinspiring sight.’’
The 38-year-old Australian naturalist has dedicated most of his adult life to the pursuit, identification, understanding and protection of the world’s largest fish, Rhincodon typus, the aptly named whale shark.
Reaching 18m in length, the huge beast resembles nothing so much as ‘a bus under water’, Norman says.
Yet an animate, placid, occasionally inquisitive bus, pursuing its mysterious life across tens of thousands of kilometres of open ocean.
First recorded in 1828, only 350 whale-shark sightings were recorded in the ensuing 150 years.
Recent growth in underwater tourism has brought a surge in sightings. Yet the whale shark remains elusive, and the World Conservation Union (IUCN), which engaged Norman to assess the species, regards it as ‘vulnerable’ to extinction.
It is protected in only a handful of countries.
Brad Norman is determined to find out far more about these fish.
His visionary plan to involve thousands of ordinary people worldwide in the photomonitoring and conservation of whale sharks, significantly enhancing knowledge of this elusive species, has earned him a 2006 Rolex Award for Enterprise — the first Australian recipient in 25 years.
The whale shark is one of only three sharks that are filter- feeders, using gill rakers to scoop up krill (shrimp), small fish and other tiny ocean life as its sole source of sustenance. It has never been known to attack humans. Tagged individuals have been tracked for 13,000km across the Pacific, and 3000km in the Indian Ocean. It has an uncanny instinct for locating food concentrations.
It is sighted at more than 100 places around the globe. Yet it remains so scarce almost nothing is known of its abundance, breeding habits or habitat preferences.
It has few natural enemies, though orcas and predatory sharks may attack young whale sharks. Now, however, the whale shark has joined the long list of species to suffer the insatiable human appetite for seafood.
Its flesh, fins and body parts are appearing in growing quantities in Asian markets where they fetch $US18/kilogram or more.
Since his first awed encounter in 1994, in Western Australia’s Ningaloo Marine Park, Norman has striven to uncover all he can about this lordly animal, whose ancestry extends back 400 million years.
‘‘My first encounter seemed quite surreal,’’ he says.
‘‘There was this huge, living thing coming directly towards me. My eyes were popping out of my head. I almost swallowed my snorkel. I was screaming silently to myself in excitement.
‘‘Yet, oddly, I wasn’t afraid. I just floated there, too amazed to swim after him.’’
As his encounters multiplied, Norman grew to appreciate many aspects of the whale shark.
Its economical 1-1.5m per second cruising speed was perfect for observation. Though able to dive as deep as 1500m, it often swam conveniently near the surface.
Its placid temperament made it safe compared with other big sharks. Yet it could also be dynamic: ‘‘I once observed seven in an area where there was a huge swarm of krill, a real soup of food in the water. They were charging through it, mouths open, thrashing around. That was a big adrenalin rush. I never felt frightened, but I did keep my arms down and made myself small.’’
‘‘Even with something as big as a whale shark, you’re not afraid — and nor is it. It is a calming experience. You feel at one.’’
Norman has mounted national and international campaigns for the whale shark’s conservation, emerging as a global expert on the animal and its needs.
Following a clue provided by an experienced fisherman, Norman’s painstaking research managed to prove that every whale shark has a pattern of white spots on its body as individually distinctive as a human fingerprint. This gave him the idea of using underwater camera images as a practical, noninvasive way to identify individuals. In 1999 he set up the ECOCEAN Whale Shark Photoidentification Library on the Internet, a global project to record sightings and images.
Despite the growing body of information, Norman lacked an efficient way to compare shots of whale sharks.
In 2002, a US computer engineer and fellow diver Jason Holmberg contacted him, offering to help organise and automate the ECOCEAN database.
He explained the photo-ID problem to a friend, NASAaffiliated astronomer Zaven Arzoumanian, whose colleague Gijs Nelemans pointed out that a technique used by Hubble Space Telescope scientists for mapping star patterns known as the Groth algorithm, might also be useful for recognising whale sharks by mapping the unique patterns of white spots on the shark’s hide.
It took many months of calculations and computer programming to refine the algorithm for use on a living creature — but they gained a breakthrough for biology: a reliable way to identify individuals in virtually any spotted animal population, without tagging or harassing them.
Ordinary people can take part in real science on ECOCEAN.
Their photos are automatically catalogued, compared and, if possible, identified as belonging to a known individual. Each new image helps Norman compile a global map of where whale sharks live and their migratory patterns.
Contributors receive notice by email of all past and further sightings of ‘their’ shark.
Together, the images are helping to build a global picture of the whale shark population.
With the Rolex Award money, Brad Norman is devoting two years full-time to his project, training local authorities, tourism operators and 20 research assistants around the Pacific, Atlantic and Indian oceans to observe, record and protect whale sharks.
‘‘It is a big, beautiful and charismatic animal, and not dangerous,’’ he says.
‘‘It is a perfect flagship for the health of the oceans.’’