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Behaviour and physiology of mountain whitefish ( P rosopium williamsoni ) relative to short‐term changes in river flow
Author(s) -
Taylor Mark K.,
Cook Katrina V.,
Hasler Caleb T.,
Schmidt Dana C.,
Cooke Steven J.
Publication year - 2012
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/j.1600-0633.2012.00582.x
Subject(s) - anaerobic exercise , range (aeronautics) , fish <actinopterygii> , biology , ecology , zoology , environmental science , physiology , fishery , materials science , composite material
Despite the growing recognition that river flow can have an effect on the growth, distribution and survival of fishes, little is known about the underlying mechanisms to explain this effect. Furthermore, there are few examples of integrated measures of behaviour and physiology to study the responses of fish to river hydrology. Here, axial swimming muscle electromyograms were logged as a sensitive indicator of activity from 19 mountain whitefish ( P rosopium williamsoni ) across a large range of hourly discharge magnitudes (mean = 621 m 3 ·s −1 , range = 0–1770 m 3 ·s −1 ) in a hydropeaking reach of the C olumbia R iver, C anada. Hourly mean discharge had a significant positive effect on swimming muscle activity. However, a large amount of the variance was unexplained, possibly due to social interactions, feeding and/or flow‐refuging behaviours. Fluctuating flows were no more energetically costly than stable flows. Discharge magnitude had a significant positive effect on blood cortisol concentrations. Yet, cortisol concentrations were low overall (mean ± SD = 1.60 ± 0.09 ng·ml −1 ), suggesting that the small observed response could be the result of routine physiological processes rather than a stress response per se . Based on low blood lactate concentrations, mountain whitefish were not swimming exhaustively (i.e., anaerobic burst‐type swimming) at high flows.