Methods for Predicting Age-0 Crappie Year-Class Strength in J. Percy Priest Reservoir, Tennessee

Abstract

We evaluated the precision and efficiency of larval townets and trap nets and correlated estimates to hydrologic parameters (temperature and spring discharge) during 1998–2002 to determine the best method for predicting year-class strength of age-0 white crappie Pomoxis annularis and black crappie P. nigromaculatus in J. Percy Priest Reservoir, Tennessee. Both larval townet and fall trap-net samples effectively sampled age-0 Pomoxis spp. and accurately indexed year-class strength. The geometric mean density of larval Pomoxis spp. in townet samples for the 3-week period bracketing peak density provided a more precise estimate of larval crappie density than the geometric mean of the 1-week peak. Larval density in May was correlated to age-0 catches in fall trap nets, so density of larval Pomoxis spp. was positively related to year-class strength. However, fall trap-net samples of age-0 Pomoxis spp. provided a more precise and cost-effective index of year-class strength than larval townet samples. May discharge through the dam was an accurate predictor of age-0 abundance in fall trap nets. This negative relation provides an early prediction of year-class strength and will be useful for supplemental stocking strategies and harvest regulation proposals.