The effect of temperature and acclimation period on repeat swimming performance in cutthroat trout

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Hatchery cutthroat trout Oncorhynchus clarki clarki were used to examine the effects of 48 h and 3 week temperature acclimation periods on critical swimming speed (Ucrit). The Ucrit was determined for fish at acclimation temperatures of 7, 14 and 18° C using two consecutive ramp-Ucrit tests in mobile Brett-type swim tunnels. An additional group was tested at the stock's ambient rearing temperature of 10° C. The length of the temperature acclimation period had no significant effect on either the first or the second Ucrit(Ucrit-1 and Ucrit-2, respectively) or on the recovery ratio (the quotient of Ucrit-2 Ucrit-1−1). As anticipated, there was a significant positive relationship between Ucrit-1 and temperature (P 〈 0·01) for both acclimation periods, and an increasing, though non-significant, trend between Ucrit-2 and temperature (P = 0·10). Acclimation temperature had no significant effect (P = 0·71) on the recovery ratio. These results indicate that a 48 h acclimation to experimental temperatures within the range of −3 to +8° C of the acclimation temperature may be sufficient in studies of swimming performance with this species. This ability to acclimate rapidly is probably adaptive for cutthroat trout and other species that occupy thermally variable environments.

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