Largemouth bass (Micropterus salmoides) fail to spawn in association with dense populations of sunfish (Lepomis sp.). Previous studies have demonstrated that suppression is behavioral in nature and linked to interspecific competition for space within spawning areas. In 1976 a series of ponds were stocked with 3 pairs of bass and densities of sunfish from 0-458 kgJha to determine the density necessary to effect suppression. Results were inconclusive with spawning occurring in all ponds but only late in the season in ponds stocked at 250 kgJha or above. It was not clear whether the growth of aquatic vegetation or cropping of the sunfish population resulted in spawning in these ponds. In 1977 a second series of paired ponds (1 with vegetation, 1 without) were stocked with 3 pairs of bass and sunfish at densities of 0-448 kgJha. In ponds without vegetative cover bass spawning was completely suppressed at 336 kg sunfishJha but spawning occurred in all ponds with vegetative cover (maximum of 448 kg sunfish /ha).
