Elusive UK dolphin re-emerges

Jody Bourton, BBC News 3 Sep 09;

An elusive dolphin has been sighted off Cornwall three years after being seen much further north in the Irish Sea.
The rarely seen Risso's dolphin was photographed off Mounts Bay in Cornwall in June of this year.

Scientists have now identified it as the same dolphin once seen 172 nautical miles away off Bardsey Island in Wales.

The new sighting will help conservationists better understand the offshore habits of this enigmatic and strange-looking creature.

Risso's dolphins ( Grampus griseus ) are found throughout the world in temperate and tropical waters. They measure up to 4m in length and have a distinctive blunt round head.

But the dolphins' preference for deep offshore waters means they are rarely seen.

"This is a fortuitous, unique and very interesting discovery," says Mark Simmonds, international director of science at the Whale and Dolphin Conservation Society (WDCS).

"Because of their typically inaccessible habits, relatively little is known about the biology or behaviour of this species and it is very interesting to know that those seen off Cornwall may be the same group as those seen in Wales."

Enigmatic lifetsyle

Compared to other dolphin species, scientists know relatively little about the structure and size of the Risso's dolphin population living around the UK.

Knowledge of their movements and appearances in different locations is therefore vital to understanding their biology.

According to the WDCS, more research needs to be done on the species, and measures taken to protect places which Risso's dolphins frequent, such as Cardigan Bay in Wales.

The water around Bardsey Island in Cardigan Bay is an important marine habitat for various cetacean species including bottlenose dolphins, harbour porpoises and Risso's dolphins.

As well as a important feeding ground, the WDCS says it is also beginning to recognise the area as a significant breeding and nursery area for the Risso's dolphin.

It hopes that further research in the area along with further sightings around the UK will help reveal more about the elusive dolphin's lifestyle.