Adaptive capacity at the northern front: sockeye salmon behaviourally thermoregulate during novel exposure to warm temperatures

Details

• Journal Title:
  Conservation Physiology
• Personal Author:
  Armstrong, Jonathan B. ; Ward, Eric J. ; Schindler, Daniel E. ; Lisi, Peter J.
• NOAA Program & Office:
  NMFS (National Marine Fisheries Service) ; NWFSC (Northwest Fisheries Science Center)
• Description:
  As climate change increases maximal water temperatures, behavioural thermoregulation may be crucial for the persistence of coldwater fishes, such as salmonids. Although myriad studies have documented behavioural 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 primary range (60° latitude) 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 (n = 40 recovered loggers). As lake surface temperatures warmed to physiologically suboptimal levels (15-20°C), 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. A bioenergetics model suggested that the observed behaviour reduced daily metabolic costs by as much as ~50% during the warmest conditions (18-20°C). These results provide rare evidence of cool-seeking thermoregulation at the poleward extent of a species range, emphasizing the potential ubiquity of maximal temperature constraints and the functional significance of thermal heterogeneity for buffering poikilotherms from climate change.
• Keywords:
  Climate Change Water Temperature Climate Change Water Temperature
• Source:
  Conserv Physiol ; . 2016 Oct 4;4(1):cow039
• DOI:
  https://doi.org/10.1093/conphys/cow039
• Pubmed Central ID:
  PMC5055284
• Document Type:
  Journal Article
• Rights Information:
  CC BY
• Compliance:
  PMC
• Main Document Checksum:
  urn:sha-512:f733c6e6398f4833326fa0b8b1606c81a7e3ecb9410034cbb722232f7ad55e5b9339d5520fe383b372011b5eba82bb39290ec14348701001a66308d989fb9838
• Download URL:
  https://repository.library.noaa.gov/view/noaa/24291/noaa_24291_DS1.pdf
• File Type:
  [PDF - 722.69 KB ]