Substrate preferences of juvenile hatchery-reared lake sturgeon, Acipenserfulvescens

Substrate preferences of juvenile, hatchery-reared lake sturgeon, Acipenser fulvescens, from a Wisconsin population were examined relative to water te mperature and velocity, fish size and time of day. Given the choice of a sa nd, gravel, rock or smooth plastic bottom, all sturgeon were strongly attra cted to the sand substrate. Water temperature did not affect substrate pref erence, however small sturgeon (13.5 cm mean FL) acclimated to 19 degrees C were more active than those tested in 6 degrees C water. Small sturgeon, u nder all conditions, were less sedentary in the early morning and late even ing hours than during the daytime. Preference of small sturgeon for sand wa s slightly stronger when a current of 5 cm sec(-1) was present. Substrate p reference of larger sturgeon (24.3 cm mean FL) was not affected by any of t he parameters examined. In general, hatchery-reared lake sturgeon showed si milar behaviors (with respect to substrate selection) as those previously d escribed for the same population in the wild, making it possible that subst rate preferences have a genetic component and likely that hatchery rearing does not alter instinctive behavior.