Evolutionary perspectives on salmonid conservation and management

Conservation and management tend to emphasize immediate demographic concerns, such as reversing population declines or maximizing productivity. These concerns have long been addressed by reference to ecological processes, but recent work has increasingly pointed to the additional importance of considering evolutionary processes. From the standpoint of conservation, adaptation might influence the collapse and recovery of populations experiencing environmental change (Bürger and Lynch 1995; Gomulkiewicz and Holt 1995; Stockwell et al. 2003; Ferrière et al. 2004; Kinnison and Hairston 2007; Carroll and Fox 2008). From the standpoint of management, evolutionary responses can influence population productivity and therefore change harvest yield (Conover and Munch 2002; Olsen et al. 2004; de Roos et al. 2006; Hutchings and Fraser 2008). In both general contexts, it is therefore important to understand how populations might evolve in response to environmental change, and how these responses might then feedback on population persistence and productivity. What is known at present is that many species experiencing environmental change also exhibit adaptive phenotypic responses, at least some of which are genetically based (Hendry and Kinnison 1999; Reznick and Ghalambor 2001; Stockwell et al. 2003; Hairston et al. 2005). Many of these responses appear driven by direct or indirect effects that humans are having on populations or their environments. For example, adaptive phenotypic changes have often been documented in response to climate change (reviews: Bradshaw and Holzapfel 2008; Gienapp et al. 2008), exploitation (review: Hutchings and Fraser 2008), and biological invasions (reviews: Cox 2004; Carroll 2008). One taxon sensitive to all these perturbations, and many others, is salmonid fishes, which are also of considerable recreational, cultural, ecological, and commercial importance. It thus seems important to focus the light of evolution on their conservation and management.