VARIATION IN PLANT STEM DENSITY AND ITS EFFECTS ON FORAGING SUCCESS OF JUVENILE BLUEGILL SUNFISH

Juvenile bluegill sunfish, Lepomis macrochirus, are known to use beds of aquatic vegetation as a refuge from predators. This study examines the effects of increasing plant stem density on juvenile bluegill foraging. Three stem densities (100, 250 and 500 stems m-2), varying in their refuge potential for bluegills from predators, were tested. Results demonstrate that stem densities chosen as a refuge from predation (i.e. 500 stems m-2) significantly reduced bluegill foraging success and increased time required to capture prey. Therefore, juvenile bluegills seeking safety in vegetation may be faced with a trade-off between foraging success and effective refuge from predation when choosing among plant stem densities. © 1990 Kluwer Academic Publishers.