Climate change provides exotic sealife with a warm welcome to Britain

A small and unusual lobster caught off the Isles of Scilly might be another pointer to global warming.

The 5in-long (12cm) slipper lobster, Scyllarus arctus, is normally found around the coasts of the Mediterranean and only about a dozen have been recorded off the UK in 250 years. But the specimen brought up off St Mary's in the Scillies by Barry Bennett, a fisherman, is the fifth to be caught in British waters since 1999.

It can now be seen in a tank at the National Marine Aquarium in Plymouth – when it is not hiding under seaweed or rocks – and it joins the growing list of warm-water fish and marine life species that are pushing further north towards the British Isles, almost certainly because the temperature of the sea is rising.

In November, Britain's first barracuda was caught, six miles off the Lizard and about 40 miles from where the slipper lobster was found. And in the past couple of years, a series of warm-water species new to Britain have been turning up, particularly from two fish families, the breams and the jacks.

The first catches of saddled sea bream and zebra sea bream were recorded in 2000 off St Austell and Weymouth respectively, while a Guinea amberjack was first recorded off Guernsey. The previous year there were five records in the West Country of the almoco jack.

Douglas Herdson, of the National Marine Aquarium, said: "As fish are very dependent on the temperature of the water, it is sensible to link these changes with changes in water temperature. They would be consistent with predictions of climate change."

Warm-water species have been turning up regularly off the coasts of Devon and Cornwall for more than a decade and some scientists believe they are clear indicators of global warming. In the late Eighties, southern species such as sunfish and torpedo rays began to appear and are now not infrequent. A series of small cold-water marine animals such as copepods were replaced by their warm-water cousins.

The waters off the West Country are an ideal place to observe such a change because they form a biogeographic boundary between northern, cold-water fish and their southern, warm-water relatives.

Natural History Note: The slipper lobster lives in warm seas, on stony ground, in caves, on muddy bottoms or in sea-grass beds, using the large spade-like protrusions at the front of its head to burrow away from danger. The head lacks a lobster's large claws and its walking legs have alternating bands of cream and brown, "making it look as if it is wearing rugby socks", the Plymouth Aquarium says.

Culinary Note You've All Been Waiting For: Yes, it can be eaten. But don't start slavering. Alan Davidson, the great authority on Mediterranean seafood, says it is "mainly used in soups".