We’re back in the incredible turquoise and blue of the Maldives, this time to discover more about the secret life of whale sharks. It is the biggest fish in the ocean, a filter-feeder in a polka dot suit. Whale sharks are found throughout the tropical oceans, but relatively little is known about their behaviour, their migratory routes – or indeed whether they migrate – their longevity, breeding habits (other than that they give birth to live young). They were only discovered (by Western scientists) in 1828.
So we jump eagerly aboard a dhoni (a traditional Maldivian fishing boat) – our home for the next couple of days – with conservation biologists Richard Rees and Adam Harman from the Maldives Whale Shark Research Programme, and the tagging expert accompanying them, Brent Stewart, of Hubbs Seaworld Research Research institute in San Diego. Brent has tagged everything from seals to sea birds to learn more about their lives, and he’s also tagged a whale shark aggregate (we’re not sure if they’re a population) off Kenya.
We set off to the area on the outside of the atoll that the guys are fairly confident we’ll find a shark. This is their second year of tagging – last year they tagged eight of the 450 whale sharks encountered in the Maldives. So far this year, they’ve managed to tag another 6. While the others keep a lookout for sharks – a kind of shark-shaped shade of coral in the water that’s pretty easy to miss or mistake coral for – Richard explains the point of the trip and what we’ll be doing for the next few days.
The group is keeping an open-access database of the sharks. This means that each time one is found, one of the guys will freedive down to take a picture of it between the fifth gill and the side fin on both left and right sides. Using software similar to fingerprinting matching technology, the snaps of the shark’s spot patterns are compared to see if it is a previously photographed one or a new find. So far they have recorded 106 on the database, almost all of which are male (possessing claspers).
And the sharks are also tagged just beneath the dorsal fin, using a harpoon. This records data including temperature, depth and light level, and the tags are tracked using ARGOS satellites. Brent is also collecting skin samples from the fish for mitochondrial DNA analysis and other studies. He is just finishing explaining the equipment to me when Adam spots a shark! We all leap into the water with fins and snorkels and race over to it.
Nick follows behind and films the whale shark (a previously photographed one, known as Jordan), and he captures Brent tagging it.
It’s an incredible sight. A beautiful 6.5-metre youngster. And then, following nearby we spot another. This poor creature has a folded bit of skin where his dorsal fin should be.
We clamber back onto the boat and Richard and Adam explain that ‘Joey’ was finned in a local lagoon. A shark fin of this size can go for US$10,000 in the Far East, and can be used as an eyecatching billboard outside a restaurant serving sharkfin soup. Joey’s story is pretty tragic sobering, despite our euphoria over being lucky enough to spot these incredible creatures. More than three-quarters of the sharks Richard’s team has surveyed have had scars or injuries from boat impacts. But as I reported last month, when I was here, the new government is beginning to take shark welfare seriously and has introduced a shark hunting ban throughout the 26 atolls.
We spot three more sharks later in the day, one of which the software reveals is previously unrecorded. It is a male, and the guys name it Nick, in Nick’s honour. He is fantastically pleased.