Research in Thermal Biology: Burning Questions for Coldwater Stream Fishes

Abstract

With the increasing appreciation of global warming impacts on ecological systems, in addition to the myriad of land management effects on water quality, the number of literature citations dealing with the effects of water temperature on freshwater fish has escalated in the past decade. Given the many biological scales at which water temperature effects have been studied, and the growing need to integrate knowledge from multiple disciplines of thermal biology to fully protect beneficial uses, we held that a survey of the most promising recent developments and an expression of some of the remaining unanswered questions with significant management implications would best be approached collectively by a diverse research community. We have identified five specific topic areas of renewed research where new techniques and critical thought could benefit coldwater stream fishes (particularly salmonids): molecular, organism, population/species, community and ecosystem, and policy issues in water quality. Our hope is that information gained through examination of recent research fronts linking knowledge at various scales will prove useful in managing water quality at a basin level to protect fish populations and whole ecosystems. Standards of the past were based largely on incipient lethal and optimum growth rate temperatures for fish species, while future standards should consider all integrated thermal impacts to the organism and ecosystem.

Keywords:

• water temperature
• global warming
• genetics
• physiology
• ecosystem
• salmonids

ACKNOWLEDGEMENT

We wish to thank Brian Beckman, Northwest Fisheries Science Center, for insight into thermal effects on gill ATPase activity and salinity tolerance.

Notes

¹Thermal niche is defined as the range of water temperature occupied or chosen by one species in concert with a variety of biotic and abiotic niche dimensions, such as food supply, habitat characteristics, or predator abundance (Magnuson et al., 1979).