ASSESSMENT OF LARGEMOUTH BASS (MICROPTERUS SALMOIDES) POPULATION CHARACTERS IN A NORTHEASTERN MEXICO IMPOUNDMENT

Abstract

We assessed the demographic characters of a largemouth bass (Micropterus salmoides) population in a small impoundment in northeastern Mexico. We collected largemouth bass across 3 years during fall and summer by electrofishing, gill netting, and seining. We evaluated size and age structure, mortality, recruitment, and individual fish growth. We also completed yield-per-recruit simulations to evaluate the effects of minimum length limits on the fishery. A common feature among length and age distributions was the rapid decline in larger fish (≥350 mm total length) and older fish (>3 years). Catch curves constructed from age-frequency data indicated an annual mortality rate of 59%. Age-frequency distributions and catch curves also indicated a stable pattern of recruitment. Analysis of mean length-at-age and von Bertalanffy growth parameters suggested largemouth bass grew rapidly early in life, surpassing 200 mm in total length by age 1 and 300 mm in total length by age 3. Yield-per-recruit simulations showed that a trade-off occurred between angler yield, number of fish harvested, and mean size of fish harvested as size limits were increased.