The Influence of Streamflow on the Recruitment of Rock Bass in the New River

Abstract Few studies have addressed the effect of stream discharge on Ambloplites rupestris (Rock Bass). We investigated the effects of spawning-season discharge on Rock Bass recruitment in the New River at 2 sites, 5 and 55 miles downstream from Claytor Dam, VA. We back-calculated length at age 1 and 2 using otoliths in order to estimate average lengths and used these values to identify age-1 fish from 14 years of fall electrofishing data on the New River. We determined a catch per unit effort (CPUE) of age-1 fish at each site and correlated it to spawning-season discharge data from the previous year using Spearman's rho rank-correlation. The CPUE at the upstream site was negatively correlated with average and maximum discharge in August, while the CPUE at the downstream site was negatively correlated with average and maximum discharge in July. August and July directly precede spawning season of Rock Bass in Virginia. We surmise that high levels of discharge strongly influence mortality in juvenile Rock ...