Midwest Fish & Wildlife Conference 2019

AUTHORS: K.B. Wood, Cassi J. Moody-Carpenter, Robert E. Colombo – Eastern Illinois University

ABSTRACT: Highly variable discharge experienced by the lower Wabash River due to a more natural hydrology pattern overlaps with Channel Catfish (Ictalurus punctatus) reproduction period; this leads to variable conditions for age-0 fish to develop upon hatching. There ubiquitous pattern of cryptic information published about age-0 Channel Catfish, and any insight would be advantageous to multiple facets in Channel Catfish life history. While a male will spawn multiple times through the year, reproduction is dictated by the females, only becoming gravid once annually; females becoming gravid at separate times leads to there being non-coeval cohorts. In their larval stages, endogenous feeding promotes a constant growth rate, but switching to exogenous feeding and entering the juvenile stages leads to growth dependent on the environmental conditions. We observed stable reproduction in varying conditions over four years of sampling (p > .05). Peak abundance in August signifies a peak in the aggregation of cohorts. Past surveys have shown there are at least five cohorts of age-0 Channel Catfish throughout the spawning season in the Wabash River; investigations into growth patterns of these cohorts by estimating daily growth from the otoliths can offer insight into which cohorts may best be utilizing their available resources. Variations in growth patterns could come from present conditions, normal seasonal variation, or a combination of both. Results from this study could aid in creating a recruitment index for Channel Catfish in this exploited lotic system.