Angling’s answer to the dodo is to be reintroduced to Britain’s rivers nearly 40 years after it died out.

The last burbot was caught in East Anglia in 1969. It is believed to be the only fresh-water fish to have died out in Britain in at least 100 years.

The fish’s future has been secured by scientists who have successfully bred more than 200 burbot fry, each 2mm long, in laboratory conditions that mimic British rivers.

Once the baby burbot have grown to a size where they are no longer at risk of being swallowed by a passing tadpole, they will be reintroduced to the rivers where they once thrived.

The burbot, known as fresh-water cod or eelpout, enjoys clean, fast-flowing rivers and deep, cold lakes. It is believed to have been finished off in Britain by pollution.

The burbot have been bred at Brooksby Melton College in Leicestershire. Experts artificially fertilised eggs from imported burbot and will use these fish for breeding so that they will have several generations available for reintroduction.

Burbot, Lota lota, grow to 14kg (30lb) and can live for 20 years. Before any are reintroduced the scientists will have to satisfy the authorities that it is safe to do so. It is thought that the burbot will be put into rivers around Cambridge.

Ian Wellby, who is leading the attempt to repopulate rivers with the fish, said: “Breeding them has never been done before in Britain. We have successfully spawned them and got more than 200 that are now two weeks old and measure up to 2mm.

“We artificially fertilised [the eggs] because this method gave us more control over the process. It has been a very steep learning curve and we have had to invent new techniques.

“It took the eggs six weeks to hatch and we are now feeding them up on plankton, but hopefully in another two weeks they will be on dry food.

“They won’t be fully grown for two years and we intend to breed from these because we want several generations.

“We don’t know what will be the best age of fish to reintroduce, or whether we should put in fish over different ages. Repopulating rivers is several years off and we have to do tests first.”

Mr Wellby said that Britain’s rivers are cleaner and less polluted than they were 40 years ago. “I think it was probably pollution that led to their decline and this was possibly helped by warmer water on rivers such as the Trent because of the heavy industry,” he said.

Burbot are common in northern Europe. The fish requires cold water in which to breed.

The burbot has a small claim to literary fame. In 1885 the playwright Anton Chekhov, a keen angler, wrote a comic story called The Burbot. It described the efforts of two Russian peasants to dislodge a stubborn burbot from the submerged roots of a tree.

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