JAMES M. LONG, Oklahoma Cooperative Fish and Wildlife Research Unit, 404 Life Sciences West, Oklahoma State University, Stillwater, Oklahoma 74078, USA

DANIEL W. BECKMAN AND ALICIA MATHIS, Southwest Missouri State University, Department of Biology, 901 S. National, Springfield, Missouri 65804, USA

Intraspecific competition and selection for habitats by size classes of largemouth bass Micropterus salmoides were studied in a manipulative experiment. Largemouth bass ('small' and 'large') habitat preferences were evaluated in artificial pools with three equal-area structures (PVC pipe stand, concrete block, and artificial grass) and pools with no structure. In pools with structure, small fish preferred the concrete blocks while larger fish preferred the artificial grass regardless of whether alone or paired with an opposite size class fish. These data indicate that size-dependent habitat preferences may reduce intraspecific competition. In pools without structure, fish of both sizes preferred the same area when alone, but only the large fish remained in this area when paired with a smaller conspecific. Therefore, when habitat preferences do not differ between size-classes, larger individuals displace smaller individuals from their preferred habitat.