Conservationists are investigating reports of a vast catch of more than 60 rare sharks by a long-line fisherman operating from a port in North Devon.

If confirmed, the haul would be one of the largest on record and a devastating blow for the population of porbeagle sharks off the isle of Lundy in the Bristol Channel where numbers had been increasing in recent years, having been fished near to extinction in the 1970s.

The catch has coincided with the first substantial study of porbeagle sharks in British waters, which included fitting several with satellite-tracking devices.

The porbeagle can grow up to 12ft and is closely related to the infamous great white. It is one of the largest predatory sharks in British waters and is hunted for its meat, which is particularly popular in France. The porbeagle’s white belly may have led to it being mistaken for a great white, sparking last week’s shark scare off the Cornish coast.

The porbeagle is listed as “vulnerable” by the European Union but has no official protection, unlike the basking shark.

Richard Peirce, chairman of the Shark Trust, which is campaigning for porbeagle sharks to be given protected status, said: “We know they form large schools and gather together by sex, so a catch of this size may well have wiped out almost all the breeding females in this particular population. It is a devastating blow.

“The boat was sailing from Bideford and we know they had caught 26 by 11am. That day we believe they took a total of 60 using a long line and went back and caught more the following day.

“Once you have located the school they are an easy fish to catch. They were probably on a refridgerated lorry bound for France within hours of being landed.”

French wholesalers will have paid about £1.50 per kg for the sharks, which can average 200kg each. The day’s catch of 60 porbeagles would have been worth in the region of £18,000.

Porbeagle steaks were selling at the Seafood Cafe in St Ives, scene of last week’s “great white” sighting, for £12.95 each.

Although the barrel-chested porbeagle has been fished commercially for decades, its numbers have declined dramatically in recent years. Norwegian fishermen managed to virtually wipe out the population in the North Sea. Commercial fishing of porbeagles off the north coast of Devon and Cornwall was also hit by declining numbers.

Long-line fishing boats use lines with hundreds of baited hooks to catch predatory fish such as shark.

The tags fitted to four porbeagles in Bude Bay, close to Bideford, last week will help to answer some of the mysteries surrounding the fish, such as how far they travel and whether they migrate across the Atlantic, as some suspect.

The tracking is being conducted by Nick Parde, a PhD student at Aber-deen University. The tags are timed to float to the surface at intervals of 30, 90 and 120 days when they will transmit data to a satellite.

Besides the depth, distance and direction taken by the sharks, scientists are trying to find out more about the connections between shark populations by studying DNA samples taken during the tagging.

Mr Peirce said: “Just because one boat was able to catch 60 porbeagles in a single day doesn’t mean there are large numbers of them out there, just that they had congregated together.”

The trust wants all sharks protected from their only serious predator, human beings. Demand for shark’s fin soup from the Far East has meant that even species like the blue shark, which are otherwise inedible, are also in danger of being fished to extinction.

In June, the Convention for International Trade in Endangered Species rejected calls for a ban on the catching of porbeagles and their smaller cousin the dog fish under pressure from fishing nations.

Cliona O’Brien, of the World Wild-life Fund, said that porbeagles in the North Atlantic had declined by 90 per cent since the 1960s.

She said: “We are seeing massive global shark declines primarily due to current unsustainable levels of fishing, and international trade is a major contributing factor. The failure to list spiny dogfish and porbeagle is a shameful triumph of politics over conservation.”

Shark tales

Latin name Lamna Nasus

Average length 3m (9.8ft)

Heaviest recorded 230kg (36st 2lb)

Colour grey/brown with white belly

Identification White patch behind dorsal fin. Crescent-shaped tail

Diet Mainly pelagic fish such as herring, lancet fish and mackerel. Also eats cod, squid and shellfish

Habitat Inhabits waters to a depth of 370m (1,214ft). Most commonly found on continental shelves or inshore. Is usually found in waters with a temperature below 14C (57F)

Number of pups in litter 3-4

Length of pups 70cm

Age to maturity 10 years

Longevity 30-40 years

Source: Times Database

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