Sea lice from salmon farms can cause a 50% reduction in runs of wild Atlantic salmon
A new study, published in the international journal Aquaculture Environment Interactions, has used 30 years of data from the Erriff river to measure the effect of sea lice from salmon aquaculture on wild Atlantic salmon.
And the results? That returns of wild adult salmon can be reduced by more than 50% in years following high lice levels on nearby salmon farms during the smolt out-migration.
The authors, Dr Paddy Gargan and Dr Samuel Shephard, conclude that “Many Atlantic salmon populations are already under pressure from (possibly climate-mediated) reductions in marine survival. The addition of significant lice-related mortality during the coastal stage of smolt out-migration could be critical”.