Fast-Start Performance of Rainbow Trout Salmo Gairdneri and Northern Pike Esox Lucius

Abstract

The escape performances of rainbow trout Salmo gairdneri (Richardson) and northern pike Esox lucius (Linnaeus) (mean lengths 0.32 m and 0.38 m, respectively) were measured with subcutaneously implanted accelerometers. Acceleration-time plots reveal two types of fast-starts for trout and three for pike. Simultaneous high-speed ciné films demonstrate a kinematic basis for these differences. Trout performing C-shaped fast-starts produce a unimodal acceleration-time plot (type I) while during S-shaped fast-starts a bimodal accelerationtime plot (type II) results. Pike also exhibit similar type I and II fast-starts, but also execute a second S-shaped fast-start that does not involve a net change of direction. This is characterized by a trimodal acceleration-time plot (type III). Intraspecific and interspecific comparisons of distance, time, mean and maximum velocity, and mean and maximum acceleration rate indicate that fast-start performance is significantly higher for pike than for trout, for all performance parameters. This indicates that performance is related to body form. Overall mean maximum acceleration rates for pike were 120.2±20.0 ms−2 and 59.7±8.3 ms−2 for trout. Performance values directly measured from the accelerometers exceed those previously reported. Maximum acceleration rates for single events reach 97.8ms−2 and 244.9ms−2 for trout and pike, respectively. Maximum final velocities of 7.06ms−2 (18.95 Ls−2) were observed for pike and 4.19 ms−2 (13.09 Ls−2) for trout, where L is body length; overall mean maximum velocities were 2.77 ms−2 for trout and 3.97 ms−2 for pike.