Artificial spawning and rearing of lake sturgeon, Acipenser fulvescens, in Wild Rose State Fish Hatchery, Wisconsin, 1982–1983

Synopsis

Attempts to culture lake sturgeon, Acipenser fulvescens, in the past have generally met with limited success. The Wisconsin Department of Natural Resources has been experimenting with artificial propagation of this species since 1979. The intent has been to develop egg collection and handling techniques, hatching regimes, larva and juvenile diet formulations, and to evaluate juvenile survival after stocking. Eggs were collected by caesarian section and fertilized with milt from ripe males taken during annual sturgeon spawning runs on the Fox and Wolf rivers in central Wisconsin. After insemination, the eggs were treated in a saturated solution of Bentonite clay and transported to the hatchery. Eggs were incubated at temperatures ranging from 13–16° C and embryos began hatching within 4 to 8 days. Hatching success ranged from 42 to 96%. Yolksac absorption was complete within 10 days of hatching. Larvae then became positively phototactic and swam actively as if searching for food. Successful larval diets consisted of live brine shrimp nauplii followed by larger zooplankton, primarily Daphnia sp. Juveniles grew best on diets of live Tubifex sp. and chopped earthworms. Liver, fish mash (ground up trout) and pelleted dry food were poorly accepted. Hatchery reared sturgeon grew more slowly than did wild fish.