Effects of live Artemia nauplii supplementation for different periods on survival and growth of juvenile signal crayfish Pacifastacus leniusculus in the first six months of intensive culture.

摘要

The rearing of astacid crayfishes under controlled conditions requires the addition of live zooplankton to basal dry diets. To investigate the possibility of minimizing the labor and costs involved in providing live feed, a 180-d experiment that focused on reducing the brine shrimp Artemia spp. supply period was carried out with stage 2 signal crayfish Pacifastacus leniusculus. From the onset of exogenous feeding, juvenile crayfish were fed a dry diet (formulated for salmonids) that was supplemented with live Artemia nauplii. Five treatments were implemented, varying the time at which the Artemia supplement was withdrawn (at days 80, 100, 120, or 160, or no withdrawal). No significant differences in survival, growth, or cheliped loss were found among groups throughout the trial. Survival rates at the end of the experiment (180 d) ranged from 62.3% to 66.7%, final carapace length averaged 20.6 mm, and final weight averaged 2.29 g. The results presented here indicate that juvenile astacid crayfishes can be reared without live feed supplements after an initial period of 80 d; thereafter, it is feasible to administer only a dry diet.