Influence of stock levels, fishing effort and environmental factors on anglers’ catches of Atlantic salmon, Salmo salar L., and sea trout, Salmo trutta L.

Abstract. Monthly catches of Atlantic salmon, Salmosalar L., and sea trout, Salmo trutta L., by anglers in a west of Ireland fishery were analysed. Data were available for 50 months from the years 1971 to 1981. The most important single determinant of catch was found to be fishing effort measured in boat-days. An additional 10 boat days were found to correspond to a catch of almost 6 salmon and 23 sea trout. The relationship between catch and stock was weaker, though a relatively high catchability of sea trout at low stock levels was recorded. Slock levels, fishing effort and environmental factors accounted for much, but not all, of the variation in catch from month to month and from year to year. Most of the effect of rainfall, sunshine and water level was attributable to variations in fishing effort associated with these factors.