Evaluation of the Swimming Performance of Several Fish Species from the Mackenzie River

Abstract

Critical velocities of 17 species of fish from the Mackenzie River have been determined from increasing velocity tests in both field and laboratory, and the effects on critical velocity of different acclimation temperatures and of temperature shock were examined. In five species the relation between fatigue time and swimming speed was investigated.Critical velocity data from 10 species were analyzed by solving the regression equation V = KL e (where V = critical velocity in cm/s, L = fork length, K = constant, e = exponent). Neither acclimation to different temperatures nor temperature shock over a range of ±7 C from acclimation temperature had a significant effect on critical velocity. Intraspecific variation was found to be unrelated to maturity, sex, or condition factor.From a graphical presentation of body length vs. maximum flow rate allowable in a 100-m culvert, it appears that culvert flow rates should be kept below 30–40 cm/s to allow successful passage of the majority of mature individuals of migratory species.