Predictions of response to selection caused by angling in a wild population of Atlantic salmon (Salmo salar)

1. Recreational angling activities in wild populations of Atlantic salmon may induce a selection pressure towards a reduction in body size and length if the angling season coincides with the return of the largest sea age fish class. 2. Using estimates of heritability for growth traits and estimates of the selection pressure from angling operating on growth, we predicted the response to selection expected to occur in a wild population of Atlantic salmon. 3. The dataset used here comprised individuals from two consecutive generations (parents and offspring) from the River Bidasoa (NW Spain). Offspring were assigned to parents using six highly polymorphic microsatellite loci. Use of restricted maximum likelihood methodology and the animal model allowed us to estimate the heritability for body length and body weight as well as their genetic correlation. 4. Estimated heritabilities (0.32 +/- 0.12 for length and 0.32 +/- 0.11 for weight) and selection pressure caused by angling were used to obtain predictions of response to selection because of angling. Our results suggested a decline of 1.9 mm in body length and 103.3 g in body weight per generation because of angling pressure. 5. The results derived from this study suggest that the angling season should be annually delayed in order to avoid selective angling of the multi-year class and further reductions in body weight and length.