Concerns for wild salmon after farmed fish escape
There is growing concern for Arran’s population of wild salmon following the escape of thousands of genetically inferior fish which escaped from the Mowi site at Carradale North during storm Ellen.
The escapees pose such a threat to the genetic integrity of Scottish wild salmon, including those on Arran, that Fisheries Management Scotland has appealed to anglers and people in the marine industry to assist them with the monitoring and mitigation of the issue.
Some of the 48,834 fish, which Mowi has confirmed to have escaped after the farm became detached from its sea bed anchors, have been washed ashore at beaches on Arran and Carradale and some have already been caught by anglers in rivers across Loch Lomond, Ayrshire, Clyde and Argyll.
Wild salmon and farmed salmon are genetically very different to each other and while farmed salmon grow very quickly they do not have the characteristics which produce stable wild populations.
In fact, their negative traits such as aggressiveness, body size, and lack of disease resistance, as well as susceptibility to wild predators, all erode the strength of the gene pool and threaten local populations.
Fisheries Management Scotland Aquaculture Interactions Manager, Polly Burns, said: ‘Fisheries Management Scotland are working with our members to ensure everything is being done to monitor the situation and mitigate where possible. Given the risks these fish pose to the genetic integrity of Scotland’s wild salmon populations, we appreciate the ongoing vigilance among the angling community. It is essential that this continues and that anglers are clear about what to do should they capture such fish.
‘Farmed fish are most usually distinguishable by damaged fins. If a farmed fish is caught it should be humanely killed. Importantly a sample of scales should be taken, which will allow us to confirm that the fish is of farmed origin. Detailed guidance on this process is available on the news pages of the Fisheries Management Scotland website. These salmon could show up further afield from the Clyde area so we’re asking all anglers on the West Coast to be aware.
‘We also need to understand any impacts this escape will have on our wild salmon through interbreeding of wild and farmed fish. Fisheries Management Scotland are working with Marine Scotland Science and Mowi to develop a genetic monitoring programme.’
‘An escape of farmed salmon on this scale is an ecological disaster’
On Arran, a number of these farmed salmon have been washed ashore on both the east and west coasts and the Community of Arran Seabed Trust (COAST) is increasingly alarmed about the developing situation.
A spokesperson from COAST said: ‘COAST is very concerned by the events at North Carradale and resultant escape of tens of thousands of farmed fish.
‘It is of no exaggeration to say that an escape of farmed salmon on this scale is an ecological disaster; on the west coast, there are only around 20,000 Scottish wild salmon left which could face extinction as interbreeding with farmed salmon results in genetic weakness and disease.
‘What is worrying is local anglers on Arran could end up catching these escapees – it is vital they do not consume them as farmed salmon, before meeting food standard levels, must complete a withdrawal phase from the chemical treatments they are exposed to; there is no way of knowing when these escapees were last treated by these harmful substances which can pose a risk to human health.
Farmed salmon can be identified from a wild salmon as they have stubby and damaged fins, deformed and damaged jaws and gills, and an increased incident of spots.
‘COAST have been receiving reports of dead salmon washing up on Arran’s shores by disgusted residents and visitors, and we urge anyone who finds a suspected farmed salmon to please call and report it to Marine Scotland on 0131 244 1833.’ The Salmon Interactions Working Group (SIWG) made several recommendations in relation to escaped farmed fish earlier this year but only once the SIWG recommendations are adopted, can the regulatory system enforce tighter restrictions and increased penalties for any escapes.
Fisheries Management Scotland is actively working with the Scottish Government to ensure these recommendations are implemented as soon as possible.