Channel Catfish Maturation in Mississippi Streams

Abstract

AbstractCommercial fisheries for wild channel catfish Ictalurus punctatus in Mississippi are subject to a single statewide minimum length limit of 300 mm. This assumes either that all populations of channel catfish in Mississippi are biologically similar or that known differences are not significant enough to override social issues, such as the enforcement of more specific regulations. We quantified sexual maturity of channel catfish from nine rivers in Mississippi to establish a biologically appropriate spatial resolution for application of length‐based harvest regulations. Age and length at 50% maturity differed among channel catfish populations from different rivers. Age and length at 50% maturity for channel catfish from all rivers combined differed among years but did not differ between sexes. Age at 50% maturity was negatively related to watershed soil fertility and positively related to mean watershed elevation, whereas length at 50% maturity was not related to any tested environmental factor (P < 0.05). Our findings suggest that sexual maturity is reached sooner in systems that have greater fertility or a longer growing season. This effect is modified by annual climatic variability (e.g., rainfall) but indicates that length‐based regulations should be applied at a river‐ or watershed‐specific scale.