Evaluation of age estimates and resulting population metrics using four aging methods from a Midwestern Blue Catfish population

Abstract

Lapillus otoliths and several preparations of pectoral fin spines have been used to age Blue Catfish Ictalurus furcatus; however, there are limited studies examining relative precision of age estimates. Further, comparisons of population characteristics (e.g., growth, mortality) resulting from age structure evaluations are needed to help fisheries managers balance resources needed to conduct investigations with quality of subsequent data. We examined sectioned Blue Catfish lapillus otoliths and sectioned pectoral spine articulating processes, basal recesses, and articulating surfaces to compare relative precision of age estimates. Additionally, dynamic rate functions and resulting population models were examined to determine if variation in age estimates resulted in divergent interpretation of population characteristics. Generally, aging precision was greatest for articulating surface and lapillus otolith sections. Although growth models generated from each aging structured differed, mortality estimates and conclusions drawn from harvest-regulated population modeling were similar across structures. These results demonstrate that although there is variability in precision and growth modeling among different Blue Catfish aging structures, estimates for key population parameters remain consistent.