Scots Waters Perfect For Basking In

August 25, 2004

Release from: James Reynolds
Scotsman.com News

COASTAL waters around the Western Isles are the best in the UK for basking sharks.

While sightings in the English Channel and off Cornwall have dropped to their lowest level for many years, the numbers of the world’s second-largest fish in waters around Coll, the Treshnish Isles, Rum and Eigg are among the highest on researchers’ records.

Last week, scientists on a Marine Conservation Society (MCS) research vessel recorded 52 basking sharks in waters off the Treshnish Isles and Canna, providing a "biological barometer" reading of the pristine health of the coastal ecosystem.

Basking sharks can reach up to 40ft in length and can weigh up to seven tonnes, making them the largest fish in UK waters and the second-largest in the world after the whale shark.

Despite their enormous size they are harmless to humans, as they feed on plankton. They can filter about 2,000 cubic metres of water (the equivalent of an Olympic-sized swimming pool) every hour as they glide through the surface waters.

Colin Speedie, the chairman of the Shark Trust, who is currently on the research vessel in the Minch recording data on basking sharks, said:

"The number of sightings so far has been extremely high around Scotland’s western coast. We have had a very poor year down in the English Channel, and it seems that the upswing is now moving more in the direction of Scottish coastal waters. This indicates that their primary food source of plankton is available in great abundance."

Mr Speedie added: "There are also minke whales galore up here, and we have even sighted a young humpback over the last fortnight around Mallaig. There is a tremendous amount of life and it is a wonderfully rich marine area."

Although numbers are up, the MCS is urging sea users to look out for the threatened species after a fisherman reported two dead sharks entangled in creel ropes off Skye and another was washed ashore on Crossapoll Beach on Tiree.

The disappearance of the species from coastal surface waters during winter months still puzzles researchers.

Some have suggested a mass movement to deeper waters and a period either hibernating or cruising in some energy- efficient mode, during which time their gill-rakers, used to strain plankton from the water, are shed and replaced.