A Comparison of Bluegill Reproductive Strategies and Growth among Lakes with Different Fishing Intensities

Abstract

Life history theory suggests that maturation schedules of male bluegill Lepomis macrochirus and the occurrence of alternative male reproductive strategies (i.e., parental or cuckolder) may contribute to the development and duration of undesirable bluegill population size structure (few fish larger than 150 mm). To investigate this relationship, we assessed parental male maturation schedules and relative abundance of cuckolders in six lakes subject to differing levels of fishing effort. Bluegills were collected by electrofishing shortly after the onset of the spawning season. Lakes with lower fishing effort had parental males that were older and larger at maturity than parental males in lakes with high fishing effort. Also, growth of parental males in lakes with low fishing effort was faster at older ages, and growth of immature males was faster than growth of cuckolders. Unlike other lakes, two of the three low-fishing-effort lakes had very few cuckolders. Our results indicate that intense fishing effort is associated with younger ages and smaller sizes at maturity for parental male bluegills. Also, increased proportions of cuckolders may be associated with increased fishing effort.