Adam Doerhoff (MS) ajdeed@mizzou.edu 882-8099

PRODUCING ALL-MALE BLUEGILL GROUPS FOR FOOD-FISH AQUACULTURE

Advisor: Dr. Hayward

Good potential exists to profitably rear Lepomid sunfish for food markets. Whereas sunfish reared only to small sizes are acceptable for pond stocking objectives, much larger fish of at least 225 g are required for food markets. Accordingly, efforts have been underway to develop techniques for increasing growth rates of sunfish, primarily bluegills and bluegill x green sunfish hybrids, so that fish of 225 g can be produced within 2 years. Whereas the hybrid sunfish has been believed to grow faster than the bluegill, a recent study at the University of Missouri has indicated that the bluegill actually possesses the higher growth capacity. This study also showed that male bluegills can far outgrow females, reaching 70% of food-market weights in recirculation tanks within just 11 months. The present study seeks to develop techniques to develop all-male bluegill groups when fish are no larger than 2-3 inches in length. One aspect of the study will evaluate the potential to simply size separate male from female bluegills when these fish are small. The capacity to produce all-male bluegill groups by sex-reversing genotypic females through exposure to male androgens at critical times is also being evaluated.