Effects of Habitat Manipulation on Reproductive Success of Individual Largemouth Bass in an Ozark Reservoir

Abstract

Centrarchids prefer nesting near patches of physical structure, and both simple and complex supplemental structure enhance the reproduction of black basses Micropterus spp. in systems where naturally occurring structure is lacking. Supplemental structure may not be helpful in systems that contain plentiful physical structure, and nests located near supplemental structure may not be as successful as nests located near naturally occurring structure. We monitored nests of largemouth bass M. salmoides in areas with and without supplemental logs in a small Arkansas reservoir containing abundant natural structure to assess how spawning individuals responded to habitat manipulation on two spatial scales, microhabitat and mesohabitat. We compared the use of natural versus supplemental logs, mating success, hatching success, nesting success, nest density, and nearest-neighbor distances in manipulated and unmanipulated mesohabitats. Nesting males used supplemental logs more often than we expected based on their use of naturally occurring logs (67% versus 25.4%, respectively). Mating, hatching, and nesting success were equally high for broods located near supplemental logs and naturally occurring structure. Manipulated and unmanipulated mesohabitat produced equal nest densities and nearest-neighbor distances. We conclude that supplemental logs were a useful management tool in Lake Wedington and provided high-quality microhabitat for spawning. We recommend that managers consider installing log structures where natural structure is sparse or floaters are abundant. Supplemental logs should be installed in a configuration mimicking the natural spacing of nests to accommodate the parental behavior of black basses.