The Use of Black Fly Larvae as a Food Source for Hatchery‐Reared Lake Sturgeon

Abstract

AbstractLive and frozen black fly larvae (Diptera: Simuliidae) were incorporated into the diets of larval lake sturgeon Acipenser fulvescens in 2002 and 2005 for a 6‐week period to determine whether fish would accept this invertebrate diet more readily than conventional bloodworm (Diptera: Chironomidae) diets. In 2002, daily feedings of live black fly larvae within an 8‐h period resulted in a mean survival rate of 37%. Adjusting the diet regime in 2005 (i.e., initial diet of brine shrimp Artemia spp., two daily feedings within a 14‐h period, and diet transition periods of 3, 5, and 7 d) resulted in overall mean survival rates greater than 80%. Survival of lake sturgeon transitioned to black fly larvae was significantly better than that of control groups transitioned to bloodworms over 3 d and statistically similar to that of bloodworm‐fed groups transitioned over 5 and 7 d. Fewer feedings and lower daily rations of black fly larvae in comparison with bloodworms did not result in differences between the final mean mass of fish in 2005. We conclude that frozen black fly larvae can reduce the effort required to transition lake sturgeon from an initial diet of brine shrimp without compromising current survival and growth standards achieved with bloodworm diets.