Fish in hot water

To inform conservation measures for fishes and improve effective fish management, the impacts of key environmental variables such as temperature must be understood. As anthropogenic factors coupled with global climate change have altered water temperatures, research has increasingly focused on understanding the mechanistic links between temperature changes and declines in native fish populations.

Fish in hot water

By Jamilynn Poletto, University of Nebraska-Lincoln, USA

Unusual aerobic performance at high temperatures in juvenile Chinook salmon, Oncorhynchus tshawytscha.

Poletto JB, Cocherell DE, Baird SE, Nguyen TX, Cabrera-Stagno V, Farrell AP, Fangue NA (2017)

Conservation Physiology 5, cow067 https://doi:10.1093/conphys/cow067

To inform conservation measures for fishes and improve effective fish management, the impacts of key environmental variables such as temperature must be understood. As anthropogenic factors coupled with global climate change have altered water temperatures, research has increasingly focused on understanding the mechanistic links between temperature changes and declines in native fish populations. Physiological performance measures such as aerobic scope, or a metabolic index positively correlated with a fish’s ability to perform activities crucial to survival, can be used to assess plasticity in response to temperatures. Poletto et al. (2017) measured the aerobic scope of juvenile Chinook salmon (Oncorhynchus tshawytscha) acclimated to one of two temperatures for several weeks (15 or 19°C), and exposed to a range of test temperatures (12 to 25°C). Across this wide range of test temperatures, both acclimation groups performed similarly and maintained aerobic scope up to 23°C, after which mortality occurred in some individuals. These results indicate that juvenile Chinook salmon exhibit a remarkable ability to maintain physiological stability through a broad range of water temperatures, and show a high degree of plasticity to cope with changing environmental conditions. Among salmonids, Chinook salmon inhabit the southern part of their range, and this ability might be a potential adaptation to cope with warmer water temperatures. The authors also suggest that the quantification of aerobic scope may be an important tool to incorporate into regional fish management, as variation in performance capabilities in other populations in the Oncorhynchus genus are consistent with local adaptation in aerobic scope.

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