Marine nature reserves may be set up around the British coast in an attempt to protect basking sharks.
The world's second biggest fish, which can be more than 30ft long and weigh several tonnes but feed only on plankton, are increasingly admired by wildlife enthusiasts from Cornwall to Scotland. Watching them as they come inshore in the summer is beginning to rival whale watching in popularity.
However, they are threatened by boat collisions, entanglement in fishing nets and in some parts of the world are hunted for their fins (to be used in shark fin soup). Formal proposals for UK protection zones for them are likely to come out of the first-ever international conference on basking shark conservation, which begins on the Isle of Man on Sunday.
The conference, which has drawn experts from all over the world, has followed on from the discovery two years ago that basking sharks are a truly global species.
This was proved when a shark tagged with a satellite transmitter off the Isle of Man coast in 2007 was shown to have crossed the Atlantic, being recorded three months later off the coast of Newfoundland. Further research has shown that basking sharks from the east coast of North America migrate down to South American waters in winter.
The conference has drawn experts from the US and Canada, South Africa, New Zealand and the Seychelles as well as from European countries from France to Norway. It is being organised by the Manx Government in conjunction with two wildlife charities, the Manx Wildlife Trust's Basking Shark Watch and the Save Our Seas Foundation.
The Isle of Man is a well-known basking shark "hotspot" with many sightings in the Irish Sea and in Manx coastal waters every year, and the species is fully protected under the island's laws.
Proposals for its formal protection in British marine nature reserves are likely to come from the meeting of the working group of Britain's basking shark Biodiversity Action Plan, which will be held on the final day of the conference next Thursday.
Dr Lissa Goodwin, marine policy officer for the Wildlife Trusts and a BAP group member, said the meeting would seek to identify conservation zones for the species. These might be included in the marine nature reserves which will be set up around the coasts of Britain under the Marine Bill currently going before parliament, likely to become a Marine Act later this year.
"There are definite threats to the basking shark in Britain, such as boat collisions and entanglement in nets, but we don't know what the level of threat is to the population as a whole, so we need to err on the side of caution," she said.
"We need to identify the areas that are important to them for breeding and feeding. The scale of development of the marine environment is such that we need to identify areas that are special to every species, and ensure that those sites which are special are given the protection they deserve."
Basking shark fins are still "incredible valuable" in the Far East, she said. There was once a basking shark fishery in Britain and Ireland but now the species is protected.
"The conference has stemmed from the realisation that basking sharks are a global species and we need to work together as partners around the world, to focus our conservation effort more closely," said Fiona Gell, wildlife and conservation officer in the Manx Government's Department of Agriculture, Fisheries and Forestry.