Effects of simulated catch-and-release angling of Atlantic salmon shortly before spawning on the viability and development of their offspring

Abstract

The principle of catch-and-release (C&R) angling is to conserve fish populations while allowing the socioeconomic benefits associated with recreational angling to continue, even at low-stock abundances. We explored how angling-associated parental stress close to spawning could influence early development of the next generation. Wild Atlantic salmon, Salmo salar, were captured on the river Blackwater, N. Scotland, during their spawning migration and exposed to different disturbance protocols intended to simulate C&R angling. Experimental fish were mated with non-experimental fish and their offspring were monitored. Mortality was higher in offspring whose parents were air-exposed. Embryos from stressed parents had smaller yolk sacs compared to controls and offspring from air-exposed parents were shorter at first feeding. Most effects were of similar magnitude regardless of the stressed parent's sex and indicated that C&R angling of Atlantic salmon close to spawning could adversely influence the offspring development. These results suggest that consideration must be given to excluding spawning periods from fishing seasons, and highlight the importance of avoiding air exposure for captured fish, as indicated by best practice guidelines.