Intraspecific differences in endurance swim performance and cardiac size in sockeye salmon (Oncorhynchus nerka) parr tested at three temperatures
Canadian Journal of Zoology
Intraspecific differences in endurance swim performance and cardiac size in sockeye salmon (Oncorhynchus nerka) parr tested at three temperatures Journal: Canadian Journal of Zoology Abstract Pacific salmon encounter widely varying environmental conditions across populations. Performance traits and environmental tolerance limits are predicted to be related to the typical abiotic and biotic conditions encountered by each population. Endurance swim performance at three different temperatures (8,
... t temperatures (8, 12, 22°C) was compared across nine populations of sockeye salmon parr (Oncorhynchus nerka (Walbaum, 1792)) from British Columbia, Canada, reared in a common laboratory environment. In addition, relative ventricular mass (RVM) was compared between good and poor performers from each population. Populations significantly differed in endurance swim performance and these differences were related to the natal lake environment. Specifically, parr populations that reside in warm, shallow lakes (Okanagan, Scotch and Stellako) had superior swim performance at 12 compared to 8°C. All other populations from deeper, cooler lakes had equivalent swim performance at 8 and 12°C. Individual variability in swim performance within a population was not due to differences in cardiac size. Similarly, RVM did not vary across parr populations, suggesting that population differences in swim performance were not associated with cardiac size. This study provides further support that sockeye salmon parr are locally adapted to their environmental conditions.