|Document Type:||Journal Article|
|Title:||Adaptive capacity at the northern front: sockeye salmon behaviorally thermoregulate during novel exposure to warm temperatures|
|Author:||J. B. Armstrong, E. J. Ward, D. E. Schindler, Peter J. Lisi|
As climate change increases maximum summer temperatures, behavioral thermoregulation may be critical for the persistence of coldwater fishes such as salmonids. While myriad studies have documented behavioral thermoregulation in southern populations of salmonids, few if any have explored this phenomenon in northern populations, which are less likely to have an evolutionary history of heat stress, yet are predicted to experience substantial warming. Here we treated a rare heat wave as a natural experiment to test whether wild sockeye salmon (Oncorhynchus nerka) at the northern extent of their range can thermoregulate in response to abnormally high thermal conditions. We tagged adult sockeye salmon with temperature loggers as they staged in a lake epilimnion prior to spawning in small cold streams. As lake surface temperatures warmed to physiologically suboptimal levels, sockeye salmon thermoregulated by moving to tributary plumes or the lake metalimnion. A regression of fish body temperature against lake surface temperature indicated that fish moved to cooler waters when the epilimnion temperature exceeded ~12°C. These results provide rare evidence of cool-seeking thermoregulation at the poleward extent of a species range and emphasize the functional significance of thermal heterogeneity for buffering poikilotherms from climate change.
|Theme:||Ecosystem approach to improve management of marine resources|
Understand how climate influences ecosystem variability.
Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species.