The Environment Agency report:

Anglers should not fish for salmon and sea trout on this Environment Agency controlled stretch of water with immediate effect; the situation will be reviewed and the fishery reopened at the earliest opportunity.

The action has been taken to reduce stress on remaining fish and ensure as many as possible successfully spawn in the river later this year. Owners of private fisheries on the Lyn are being encouraged to introduce a similar voluntary closure in a bid to safeguard stocks.

Symptoms shown by diseased salmon and sea trout include open lesions around the head and fungus on fins and other parts of the body. A similar outbreak occurred on the East Lyn last year.

The Environment Agency has launched an investigation into the fish mortalities and will monitor the River Lyn throughout the summer to establish the cause of the problem.

Salmon are being tested at the Environment Agency’s National Fisheries Laboratory to identify the disease. Migratory fish are prone to stress caused by low flows and rising water temperatures and this can exacerbate any underlying health problem and make them vulnerable to disease.

Mike Holland, speaking for the Environment Agency, said:

“It is not uncommon to see fish with fungal infections during the summer. However, we have decided to temporarily close the East Lyn fishery because of the high incidence of diseased fish and the associated fish deaths in the river this year.

We will decide whether or not to re-open the fishery once we’ve had the results back from our National Fisheries Laboratory and have completed our monitoring of the river, including the fate of new fish running into the river from the sea,’ explained Mike Holland.”

The disease only affects migratory salmon and sea trout. Other fish in the river appear to be healthy.

People can report any sightings of diseased fish on the Lyn or any other west country river by calling the Environment Agency’s free 24-hour incident hotline 0800 80 70 60