Ecological and economic costs of supportive breeding: Atlantic salmon ( Salmo salar ) as a case study

Supportive breeding is a common management action carried out to enhance Atlantic salmon populations in the region of Asturias (northern Spain), but its real success is yet unknown despite the high effort expended in the last decades (since 1992). Identification of returning adult salmon as hatchery descendants was carried out with microsatellite loci and pedigree tests in two rivers of the region (Sella and Cares). High levels of straying between rivers and rates of return between 6% and 11% of Atlantic salmon hatchery descendants in sport fishing catches were found. The estimated cost of each salmon caught was higher than €4000.