Molecular Analysis of the Accuracy of Phenotypic Sex Assessment by Anglers in Norwegian Atlantic Salmon Fisheries

A management regulation applied in some recreational Atlantic salmon (Salmo salar) fisheries is a moratorium on harvest of female fish, which can only be effective if recreational anglers can consistently discriminate females from males. We used molecular methods to compare angler-reported sexes of salmon captured in Norwegian populations with the true sexes of the same individuals. We made this comparison (i) among rivers that were subject to female no-take policies or not within the same year; and (ii) within rivers before and after a female no-take regulation was instituted. Sex was misclassified for ca. 25% of salmon that were true females, especially those that were large or captured early in the season. Furthermore, true females were misclassified more often when a female no-take regulation was in effect. We conclude that a management regulation aimed at protecting female salmon in recreational fisheries may be less effective than expected.