Farmed salmon that escaped from a fish farm in Killary Harbour have been found in three of Ireland’s most important angling rivers nearby.
Anglers and environmental groups have highlighted their concerns about the threat to wild salmon stocks, and potentially to human health, as some of the fish were reported to be diseased.
Inland Fisheries Ireland (IFI) said it believed the escaped farmed salmon “pose a significant risk to wild Atlantic salmon populations” as wild salmon in the nearby Erriff and Bundorragha rivers are currently returning to their river of origin to spawn.
“A very significant number of farmed salmon are now in the marine environment, and could travel up these rivers. The wild salmon of each river are unique genetically. IFI is concerned that interbreeding with farmed salmon could compromise the genetic integrity of the local salmon population, which could impact their resilience in the long term,” it added.
An estimated 10,000 to 30,000 farmed salmon escaped from a facility operated by Mannin Bay Salmon Company on August 11th. The company confirmed that divers discovered a tear on one of their nets on a routine dive. By Wednesday of this week, 10 escapees had been caught on the Erriff river, four on the Kylemore and two on the Delphi.
“This is disastrous ... The escapees are in very poor condition and are obviously diseased,” according to Billy Smyth of Galway Bay Against Salmon Cages (GBASC).
The risk is that the farmed salmon would breed in coming months with wild stocks, he said, rejecting the view of the fish farm operator, who said these fish would not mature until winter 2025 at the earliest and survival until then would be minimal.
“We are concerned the offspring of interbred salmon could be less adapted to their river, affecting their long-term reproductivity and survival,” the IFI said. “Salmon are already under threat from water quality, habitat degradation, illegal fishing and climate change, and this incident poses an additional challenge to salmon populations in rivers in Galway and Mayo.”
GBASC rejected the view from the fish farm operator that the number of escapees was “insignificant”.
“IFI has not received information about the health of these farmed fish, so cannot comment on the presence or absence of diseases in them,” its spokesman said.
The licensing authority, the Department of Agriculture, Food and the Marine, said it will not have details on numbers of fish that may have escaped “until the report on this incident is completed”.
Salmon Watch Ireland (SWI) called on the Marine Institute, Food Safety Authority and BIM to clarify the implications for wild salmon and possible risk to human health.
“These fish are being caught both in salt water and in freshwater catchments flowing into Killary and some are being consumed. It is our strong opinion that these fish should under no circumstances be eaten as they may be harbouring significant residues of antibiotics, vaccine residues and indeed antiparasitic medicines,” SWI said in a statement.
“We also wish to ascertain if any disease was present on the farm which could affect wild salmonids. It is common practice to starve fish prior to harvest to reduce any medication present but these fish were actively feeding and thus may prove to be harbouring high levels of antibiotic residue and antiparasitic medicine,” it added.
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