Seasonal changes in fast-starts in the short-horn sculpin: integration of swimming behaviour and muscle performance

In short-horn sculpin Myoxocephalus scorpius, the power requirements for fast-start swimming and the length-specific velocity of the curvature wave travelling down the spine ((U) over cap) were not influenced significantly by acclimation to summer and winter conditions at test temperatures of 5 and 15 degrees C. However, in-vivo and in-vitro muscle performance exhibited acclimation responses at 15 degrees C. Seasonal acclimation altered the escape performance curves for power and (U) over cap significantly over a wider temperature range of 0.8-20 degrees C. (U) over cap was significantly higher at 20 degrees C in the summer- than winter-acclimation group. The acclimation of lower levers of physiological organization at 15 degrees C may thus serve to extend the thermal limits for escape performance in summer acclimated fish. (C) 2000 The Fisheries Society of the British Isles.