Growth and Survival of Larval Bluegills in the Laboratory under Different Feeding Regimes

Abstract

Abstract The objective of this study was to develop a procedure for rearing larval bluegills Lepomis macrochirus in tanks. In preliminary experiments, seven commercial diets were fed to larval bluegills from the onset of exogenous feeding to 28 d posthatch. Although all diets were eaten by the larvae, none were observed to pass through the fish's digestive tract, and survival was essentially zero. In the next set of experiments, bluegill larvae survived on commercial diets when they were fed nauplii of brine shrimp Artemia franciscana for an initial 7-d period before being switched to commercial feed. Using this protocol, we compared three feeds (BioKyowa Fry Feed Kyowa B-250, Argent Hatchery Encapsulon Grade II, and Zeigler Larval AP-100) over a 28-d period. There were no significant (α = 0.05) differences in growth (length and weight) among fish fed the three diets at the end of 28 d, but survival was significantly higher for fish fed BioKyowa. In another experiment, we fed BioKyowa to larval bluegills after feeding them brine shrimp nauplii for 3, 7, or 14 d. Larvae fed brine shrimp for 14 d had significantly higher growth and survival than larvae in the other two treatments. Our results indicate that the feeding protocol for tank-rearing larval bluegills should start with brine shrimp before a commercial diet is used.