BASKING SHARK PROJECT

The objective of this project, a registered charity, is to achieve, through scientific research and public education, a better understanding of this fascinating species.

Although the basking shark is the world’s second largest fish, growing up to 35 feet in length and weighing up to five tons, there is surprisingly little known about its population, distribution, behaviour or biology. Its mating habits and reproductive cycle are a mystery other than it gives birth to live young after a gestation period of a year or more.

It’s name derives from the fact that they can often be seen on calm, sunny days, ‘basking’ at the surface. There have been reports of large shoals with over 100 but these sightings are becoming rare, single fish are most commonly seen. They swim along at a leisurely one or two knots with their mouths wide open, each filtering seawater at a rate of 330,000 gallons an hour to extract plankton through mucus covered gill-rakers.

The project is conducted from the University of Liverpool Marine Biological Station at Port Erin on the Isle of Man. It is led by Ken Watterson who has been studying the creature on a voluntary basis for over 10 years. He has spent hundreds of hours observing the sharks from cliffs and boats as well as swimming in close proximity to them. All their behaviour and identifying features are recorded in a database.

One of the first tasks of the project was to establish a telephone and card sighting scheme that now extends throughout Britain. The reporters include fishermen, ferry crews, coastguards, lighthouse keepers, life boatmen, yachtsmen, divers, coastal walkers and tourists. A shark hotline to which the public can phone for the latest sighting information has been established, a shark telephone card released and a song recorded. More recently a Basking Shark Club has been launched for people who are interested in contributing more towards ensuring its survival.

A tagging programme has been undertaken for several years and scientists worldwide supply the project with tissue specimens for DNA fingerprinting studies as well as vertebral samples for age analysis. Working in collaboration with the Sea Mammal Research Unit in England and the Woods Hole Oceanographic Institution in America the project has been assessing ways in which they can obtain more information about shark migratory movements through satellite tracking.

The basking shark is gradually disappearing from areas where they were previously common but the Irish Sea still appears to hold one of the world's largest concentrations. They arrive in April but scientists are unsure where they originate from, whether they come for reasons other than to feed, and where they go to on departure in the Autumn. One theory is that, given the lack of plankton to feed on, they might shed their gill-rakers and lie in a semi-comatose state on the seabed. However, it is more likely they simply move offshore into deeper waters or migrate to new feeding grounds.

Despite our limited knowledge the Norwegians, the Portuguese, the Californians and one Scottish fisherman still hunt for sharks. It is estimated that 5000 are harpooned each year for their enormous oil-rich livers, which make up 25% of their bodyweight, despite the fact that there are synthetic oils available. This oil was traditionally used for lighting and medicinal purposes but nowadays is valued for its squalene content, a hydrocarbon that is used in the cosmetics industry and as an additive to the hydraulic fluid used in high altitude aircraft engines. The carcass meat is usually dumped but there is a growing interest in the sale of its tail and fins. These financially lucrative by-products are used for an exotic soup and are removed leaving the sharks, often still alive, to sink to the bottom of the sea.

Ken’s observations have shown that of the surface feeding animals (which of course are the ones killed by the hunters) approximately 95% are females. The selective removal of this group obviously has severe consequences for a species whose numbers remain unknown. It is also believed that populations are highly localised and therefore more likely to suffer from over-fishing if there is no recruitment from outside their immediate area.

As a result of the continued hunting elsewhere there has been renewed calls for the basking shark to be afforded full protection in UK waters. Ken Watterson and others are striving for it to be designated a protected species under the Wildlife and Countryside Act of 1981 which is presently undergoing its third five-yearly review.

Another immediate goal of the project is to establish a Shark Research Centre on the Island. The Isle of Man Basking Shark Charitable Trust was officially launched in July 1995 and subsequently televised by the BBC to raise funds in order to appoint a full-time marine biologist and purchase tagging equipment.

For further information contact:

Ken Watterson,
Cronk Moar,
Curragh Road,
St. John’s,
Isle of Man,
IM4 3LN.
Tel : (01624) 801207
Fax : (01624) 801046
E-mail : bskshark@enterprise.net