Salmon and sea trout have been showing symptoms of the disease which the Environment Agency is trying to identify.
THE Environment Agency has closed the Watersmeet and Glenthorne fishery on the East Lyn after a higher number than normal of fish deaths.
As of today, anglers are advised not to fish for salmon or sea trout in this stretch of water.
Salmon are currently being tested at the Environment Agency’s national fisheries laboratory to identify the disease.
Symptoms include open lesions around the head, and fungus on the fins and other parts of the body.
Mike Holland, of 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.”
The action to close the fisheries has been taken to reduce stress on the remaining fish and ensure as many as possible successfully spawn in the river later this year.
The disease only affects migratory salmon and sea trout and other fish in the river appear to be healthy.
The Environment Agency has said it will review the situation and aims to reopen the fishery at the earliest opportunity.
You 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 on 0800 80 70 60.