Whale shark found a long way from home

Annie Guest, ABC News 31 Jan 08;

A young whale shark has been found off the Queensland coast, as far as 1,000 kilometres off course of its annual migration.

The discovery has puzzled scientists, who have not ruled out a link to climate change.

The lonesome whale shark comes from the world's biggest fish species, characterised by a wide flat mouth and covered in white stripes and spotted skin.

It is a highly migratory species, but to be seen off Stradbroke Island in Queensland's south is extraordinary.

Ken Holzheimer has been operating dive boats in the area for almost 40 years. Divers from his boat identified the rare, and usually warm water dwelling, sea creature earlier this week.

"You go to Ningaloo in Western Australia, that's where they are all the time and all of a sudden one turns up here," he said.

"I only heard about it when the divers came back to the boat, and I disputed the fact that it was there until they showed me their cameras with the photos on it.

"Then I had to believe them, didn't I?"

"There was no doubt about that. With the white spots, it was definitely a whale shark."

The veteran dive boat operator has never heard of a whale shark around Stradbroke Island.

He says the divers initially mistook it for a tiger shark. Mr Holzheimer says they saw its fins in the distance, and soon it swam closer and circled them, without showing any signs of distress.

"[It was quite a healthy specimen, and hung around with them within touching distance."

Mr Holzheimer says the whale shark hung around for 15 to 20 minutes of the dive before swimming away.

"It was just too much for [the divers]. They'll definitely be back."

Scientists puzzled

The divers are not the only people to be excited by the discovery.

Scientists are also taking a keen interest, examining the photographs taken by the divers.

Simon Pierce, the lead scientist from the University of Queensland's Manta Ray and Whale Shark Research Centre, says it is very unusual to see whale sharks this far south.

"The only [report of a whale shark sighting] that I know of is from the 70s around here, and there's historical records down in New South Wales as well, but certainly nothing that I'm aware of was in the last decade or so," he said.

He says the whale shark most likely came from somewhere in the Indo-Pacific region, like in the Pacific Ocean or Coral Sea.

"It's probably travelled several thousand kilometres to get here," he said.

Mr Pierce thinks this five-metre whale shark was a juvenile, about 20 years old. He says whale sharks can live for up to 100 years and reach 20 metres long.

He is uncertain why the slow-moving fish may have travelled such a distance.

"Sometimes they do wander quite far from their natural range. It's probably looking for a food source," he said.

He says this sighting could potentially be linked to climate change creating warmer southern currents.

"We do know that whale shark movements are quite linked to currents, but it's difficult to say," he said.

"If we start seeing them more consistently over the next few years, then I would guess it probably is linked to climate change."