Aquaculture: protecting precious resources
Warning of “extinction vortex” in salmon farming areas
Any doubt about the devastating impact sea lice levels can have on wild salmon and sea trout stocks will have been swept away by a report from Inland Fisheries Ireland that envisages an “extinction vortex” in salmon farming areas in the absence of remedial action.
Published by Samuel Shephard and Patrick Gargan and based on 26 years of statistics from the Erriff River that flows into Killary harbour on the Mayo/Galway border, the report finds that elevated lice levels have reduced annual returns of wild fish by some 50 per cent. Rising sea temperatures and other factors are also limiting survival rates but salmon farms are the biggest threat.
Initially, it was thought that lice infestation on salmon farms only affected sea trout stocks. But falling wild salmon numbers, in spite of a ban on drift netting, tells a different story.
Proposals from Bord Iascaigh Mhara envisaged the licensing of enormous salmon farms along the West coast. On the basis of this study, such large-scale aquaculture developments would be unwise and existing farms should be rigorously monitored for sea lice infestation to protect remaining wild salmon and sea trout stocks.