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Tell me about the basking shark

01:00 Mon 05th Mar 2001 |

A. Unlike the more famous great whites, basking sharks are harmless and are often described as the gentle giants of the sea. They feed only on plankton, which they catch by swimming along with their mouths open, filtering up to 2,000 cubic metres of water an hour through their gill rakers. The fish are the largest found in UK waters, growing up to 10 metres in length and weighing up to seven tonnes. They are sighted around the UK from March onwards. However, their winter habitat is unknown.

Q. Why are basking sharks endangered

A. Unfortunately, although the species is protected in British waters, rapid population decline has been recorded in recent years.

The sharks are threatened by habitat pressure, food availability and by commercial fishing. Large numbers have been caught in the past for their liver oil, meat, cartilage and fins. Basking shark fins are particularly valuable because of their large size, sometimes fetching up to �10,000 each.

Additionally, they mature slowly and have very few young. Conservationists say they are one of the most vulnerable shark species.

Q. What is being done about the decline in basking shark numbers around the UK

A. The government has pledged a �215,000 package of research funding. The money will be used to appoint a programme officer to the Shark Specialist Group and fund research on population structures, dynamics and movements and attempt to cut needless deaths and encourage the recovery of the species.

The Centre for Environment, Fisheries and Aquaculture Science (CEFAS) will carry out the research.

The UK Government is also demanding restrictions on the international trade in the sharks. It is hoping to have the basking shark placed on Appendix II of the Convention on International Trade in Endangered Species (Cites), during the next round of talks in Chile in 2002.

Q. How will research into basking sharks be carried out

A.Using small data tags, fitted to the sharks. The devices, which are the size of a large cigar, record water temperature, depth and light levels. It is hoped that the tagging will provide a much better idea of the sharks' movements and habits.

The tags automatically drop off after a short time, float to the surface and send their data back to the UK via satellite.

by Lisa Cardy

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