Escaped salmon with deformed fins threaten wild stocks

Deformed Scottish salmon that escaped captivity are invading English rivers and risk mixing with wild purebreds.

The invasion - caused by a mass breakout of 50,000 fish from a salmon farm in the Firth of Clyde during Storm Ellen in Augus - has been described as “potentially incredibly damaging “ to the wild salmon population.

They have been turning up in Scottish rivers ever since, causing alarm to anglers.

Now it has been confirmed that six farmed fish have been caught on the River Ehen, the Border Esk and on the Cumbrian Derwent river, all in Cumbria, with more fish suspected to be in other local rivers.

There is no risk to human health, but it is feared that the fish will breed with natural wild salmon and deplete stocks.

Due to being raised within the confines of farms, the farmed fish have deformed or shortened fins, gill covers, snout and heavy pigmentation - meaning they are often more spotty than wild salmon.

It is the last month of the fishing season and the Environment Agency and Fisheries Management Scotland are warning anglers to be vigilant.

Brian Shields from the Environment Agency, said: “We want to see as many wild fish spawning as possible to benefit future fish generations which is why we want to make sure these farmed fish can be removed from our rivers, within the law, to prevent future damage to the wild stocks.

“We are working closely with Fisheries Management Scotland to co-ordinate the recording of these farmed fish captures, and we are asking anglers to be vigilant to these escaped fish for the last few weeks of the fishing season”.

Fisheries Management Scotland Aquaculture Interactions Manager, Polly Burns, said: “This is terrible news. These salmon are from Norwegian stock so are genetically different from the indigenous salmon.

“Plus, they are bred to be fat and good for eating. They don’t have the genetic characteristics so their off-spring are less likely to survive.

“We are asking anglers in England and on the Border Esk to use the same reporting system anglers are using in Scotland to keep catch records of these farmed fish in one place.

“Farmed fish are most usually distinguishable by damaged fins. If a farmed fish is caught it should be humanely dispatched.

“Importantly a sample of scales should be taken, which will allow us to confirm that the fish is of farmed origin.

“We feared these fish could turn up further afield and that stresses the importance of anglers being aware wherever they may be fishing on the West coast of the UK.”

The Carradale North site, Mowi farm, saw 48,834 fish escaped after the farm became detached from its seabed anchors during Storm Ellen.

Fisheries Management Scotland have been making efforts to manage and mitigate the escape, however, confirmed cases of escaped farmed salmon caught a hundred miles away on the River Derwent and the Border Esk. Escaped farmed fish can damage the genetic integrity of wild populations.

They can also out-compete wild fish for food and habitat.