Meeting Abstract

S9-2.4  Monday, Jan. 7  Evolution of tolerance to multiple interacting stressors in fish SCHULTE, PM; University of British Columbia pschulte@zoology.ubc.ca

Anthropogenic environmental change, which involves changes in multiple interacting environmental stressors, is having important effects on animals living in aquatic environments. Although we have a fairly good understanding of the effects of abiotic stressors in isolation, our understanding of the effects of these stressors in combination is limited, which limits our ability to make predictions about the responses of fish to anthropogenic environmental change. Here, I review the available literature on the responses to interacting abiotic stressors such as temperature, hypoxia and salinity in fishes, with a focus on work from my laboratory on killifish (Fundulus heteroclitus), threespine stickleback (Gasterosteus aculeatus) and Atlantic salmon (Salmo salar). These data suggest that these stressors may act synergistically such that small shifts in multiple stressors could result in large effects on organismal performance. There is substantial intraspecific variation in tolerance to individual stressors in many species of fish that could act as the raw material for evolution of improved tolerance. However, the potential for adaptive evolution in the face of multiple interacting stressors will depend, in part, on the genetic correlations among tolerance traits. For example, negative genetic correlations (or trade-offs) between temperature and hypoxia tolerance could limit the potential for adaptation, while positive genetic correlations might be of benefit. The limited data currently available suggests that hypoxia and high temperature tolerance may be positively correlated in at least in some species of fish suggesting the possibility for adaptive evolution in these traits in response to anthropogenic environmental change.