Trawler crews are believed to have decapitated the dolphins after the creatures - seen as a symbol of the environmental movement - became entangled in their nets. Worried about rising public anger at the number of dolphins that die after being caught in fishing nets, fishermen are cutting them to pieces in the hope they will sink out of sight rather than be washed up on a beach.
But the tactic is backfiring. Two decapitated dolphins have been found this year: one on the Lizard peninsula in January and, last week, a second off the south Devon coast near Brixham. Earlier this year a third, a Risso's dolphin, was found in Devon waters with its tail sliced clean away.
Their discovery follows six decapitations off Cornwall last year and has alarmed both conservationists and the beleaguered fishing industry, which fears a backlash from the public.
Fishermen consider the accidental catching - or "by-catch"- of dolphins an unavoidable industrial hazard. Replacing broken nets is time-consuming and expensive. The majority support greater research into sonar technology which may guide dolphins away from the nets. However, one dolphin which was washed up had slices of flesh removed from its torso, suggesting that fishermen have on occasion taken the chance to try out ready-made "dolphin steaks".
The most recent case, involving the body of what is thought to have been a 5ft bottle-nosed dolphin, was discovered on Westcombe Beach, near the village of Kingston in south Devon. The dolphin's head had been sliced off cleanly just above the dorsal fin.
"It looked a piece of frozen meat that had been left in warm water to defrost," said Linda Hingley of Seawatch, a Devon-based monitoring group for dolphins, porpoises and whales. "I was deeply moved when I saw it. It was a beautiful day, a wonderfully deserted beach, it was very peaceful and here was this once beautiful creature. It was a humbling experience."
The dolphin had clearly been decapitated before it had landed on the beach, she said. "These dolphins are being washed up like this, so we know it isn't some weirdo walking around looking for dolphins to cut up and take their heads home as a trophy, though that has happened in the past."
The decapitations have highlighted again the devastation wreaked on dolphin numbers by industrial trawling. Dolphin strandings - where a dead animal is washed up on shore - are on the rise in the south-west. In Cornwall, 28 dolphins, including the bottle-nosed, Risso's and harbour species, and whales have already been washed up on the county's beaches this year, compared with 65 for the whole of 1998 and 52 in 1997, according to the Cornwall Wildlife Trust. In Devon, around 30 were washed up last year.
The vast majority of stranded dolphins - around 80 per cent - die after being caught up in fishing nets. Others die of pollution and a handful inadvertently beach themselves. Conservation groups and fishermen are working closely on reducing the number of dolphins caught in nets. Most dolphins and their smaller cousins, the porpoises, are caught in large industrial trawlers from Scotland and France, which have already scooped up more than 1.5m mackerel and sea bass off the south-west coast this year, using nets that spread up to a mile wide. Entangled in a net, a dolphin or porpoise will shut its blow-hole and suffocate.
According to the Whale and Dolphin Conservation Society, the porpoise is almost extinct in southern British waters. "We have a major scandal going on which needs urgent attention," said Mark Simmonds, the society's head of science, who is puzzled by the latest development. "I can't see why they would cut a head off unless they wanted to take a trophy home."
The fishing communities of the south-west are concerned at the impression the decapitations will make on the public. "It's sad for the actions of a very small minority of fishermen to act in this way and present fishermen in this ghastly light," said Mrs Hingley.
"It's one thing catching them accidentally but we've got to deal with what is a growing problem. If fishermen are trying to dispose of dolphins in this way people are going to wonder what they're trying to hide by disposing of the evidence."
Fishermen have also moved to condemn the actions of their colleagues.
"It's a fact of life that an accidental by-catch of dolphins and whales occurs, but we want the public on our side when it comes to our battles with Westminster and Brussels," said Phil Midgley, of the South West Fish Producers Organisation.
"The industry is very small and word will get around quickly about who is doing this. You will always get a few hotheads. They're obviously worried about the public perception of a stranded dolphin and decapitate it in the hope it will sink to the bottom of the sea."Reuse content