Sustained Swimming Ability of Larvae of Walleye (Stizostedion vitreum vitreum) and Yellow Perch (Perca flavescens)
Sustained swimming ability of limnetic larvae of walleye and yellow perch from Oneida Lake, New York, was compared in an experimental apparatus. The current velocity that 50% of the larvae could sustain in 1-hr tests was recorded for each 1-mm length class. Yellow perch larvae swam better than walleye larvae for length classes less than 9–10 mm total length (TL), but swimming ability of the two species was equal for length classes from 9 to 15 mm. Velocities that larvae under 9.5 mm TL could sustain were less than 3.0 cm/sec, and it was concluded that newly hatched young of both species would be subject to transport by lake currents of greater velocity. Relative swimming ability, expressed as the number of body lengths/sec that a larva could sustain for 1 hr, approached an asymptote between 3 and 4 lengths/sec for larvae longer than 9.5 mm. The greater swimming ability of newly hatched yellow perch larvae, compared with that of walleyes, appeared to be related to the smaller yolk sac of yellow perch at hatching.