Temperature Effects on Acceleration of Rainbow Trout, Salmo gairdneri

Abstract

Acceleration performance during and immediately following fast-starts was measured at 5, 10, 15, 20, and 25 °C for rainbow trout (Salmo gairdneri) of mean mass 23.5 g. Fast-start responses were initiated by an electric shock stimulus. Temperature had little effect on fast-start kinematics. Response latency and duration of propulsion strokes decreased with temperature. Latencies decreased from 23 ms at 5 °C to 6 ms at 25 °C. Times to complete the first two principal acceleration strokes in a fast-start decreased from 116 ms at 5 °C to 65 ms at 25 °C. Distance traveled in a given time increased with temperature. For an elapsed time of 100 ms, the distance traveled was 3.5 cm at 5 °C increasing to 11.3 cm at 25 °C. Velocity increased with time at each temperature to reach maximum values by the end of the third propulsive stroke and thereafter declining. Maximum velocity increased with temperature from 0.99 m∙s−1 at 5 °C to 1.71 m∙s−1 at 15 °C. Maximum velocity was independent of temperature from 15 to 25 °C. Similar trends were found for maximum acceleration rate which increased from 16 m∙s−2 at 5 °C to 41 m∙s−2 over the 15–25 °C range. Temperature effects on acceleration performance would alter the ability of fish to traverse short areas of high velocity flow, the effectiveness of predators, and vulnerability of prey fish. Key words: trout, acceleration, swimming, fast-start, temperature, predation, locomotion