Interaction between seals and salmon drift net fisheries in the west of Ireland

Abstract

The common seal Phoca vitulina L. and the grey seal Halichoerus grypus F. are both present in colonies along the west coast. The common seal inhabits bays and estuaries and inlets with sandy bars mainly in Galway Bay, Clew Bay, Co. Mayo, Ballysadare Bay, Co. Sligo and Donegal Bay. The grey seal is more widely dispersed particularly in the summer months and can be seen in bays, estuaries and offshore islands. Widespread complaints by salmon fishermen in Galway Bay of severe predation by seals on salmon caught in drift nets in 1978 led to a programme to study the problem. In 1979 and 1981 direct observations on board two salmon drifters were made in Galway Bay and in 1980 and 1981 similar work took place on three boats in Sligo Bay. In addition, two crews were interviewed in port each evening. In 1980 salmon landed in Donegal, Galway and Kenmare were examined at market points and the number of seal damaged fish recorded. This leaflet gives the results of the study and concludes that effective control requires measures against the seals which are actually robbing the nets. Destruction of seals at breeding colonies is unlikely to have any positive effect on the rate of predation.