Comparative Influences of Gizzard Shad Catch Rates and Reservoir Hydrology on Recruitment of White Bass in Kansas Reservoirs

Abstract

We evaluated the effects of reservoir hydrology (April/May inflow (m³/s) and April/May storage ratio (reservoir volume at conservation pool/monthly discharge)) and catch per unit effort (CPUE) of gizzard shad Dorosoma cepedianum less than 18 cm long on the CPUE of age-0 white bass Morone chrysops in 16 Kansas reservoirs from 1981 to 2000. Hydrological data were collected from U.S. Geological Survey gauging stations and the U.S. Army Corps of Engineers. Data on gizzard shad CPUE were from summer seine hauls and fall gill-net samples. The recruitment of white bass was indexed using the CPUE of age-0 white bass from fall gill-net samples. The CPUE of age-0 white bass was positively correlated with that of gizzard shad for 44% of the reservoirs, and spring inflow was a positive correlate for 19% of the reservoirs. Variation in the CPUE of age-0 white bass was best explained by a two-variable model (gizzard shad CPUE and April inflow) for only one reservoir. There was no relationship between the CPUE of age-0 white bass and the CPUE of gizzard shad or hydrological variables for five reservoirs. The variability in the recruitment of white bass was best explained by models for individual reservoirs because regional models lacked predictive capability.