Vulnerability of striped bass Morone saxatilis Waldbaum eggs and larvae to predation by juvenile white perch Morone americana Gmelin

Abstract

Striped bass Morone saxatilis Waldbaum early life stages and juvenile congeneric white perch M. americana Gmelin co-occur in Chesapeake Bay tributaries. Vulnerabilities of striped bass eggs and laboratory-reared larvae to predation by juvenile (58–65 mm total length) white perch were determined. Predation experiments of 15-min duration were carried out in 76-1 tanks with individual predators. Vulnerability of striped bass larvae was directly related to light level in the range 0–1000 lux, but turbidity level (0–15 NTU) had no effect on vulnerability. Eggs and larvae that were progeny of large or small female striped bass, and which differed in size-at-age, were found to be equally vulnerable to white perch predation. Predation rate on eggs was relatively low (1.7·15 min −1), increased on yolk-sac larvae (7.3·15 min −1) and was highest (13.1·15 min −1) on 12-day posthatch larvae, after which it declined. Larvae of 7.0–7.9 mm standard length and 0.25–0.49 mg dry wt were most vulnerable. Predation by white perch on striped bass eggs and larvae potentially is a significant cause of mortality in Chesapeake Bay tributaries, although additional laboratory and field experiments are needed to quantify its impact.