Striped Bass Egg Mortality, Production, and Female Biomass in Virginia Rivers, 1980–1989

Abstract

Abstract A Lagrangian time-series study of egg abundances of striped bass Morone saxatilis in the Pamunkey River in 1987 yielded mortality estimates of 10–91%/d. Mean daily mortality (68%/d) was incorporated into a model used to estimate annual egg production and female biomass from results of ichthyoplankton surveys conducted on Virginia spawning grounds in the Mattaponi River (1980), Pamunkey River (1980, 1983–1985, 1988–1989), Rappahannock River (1982–1983), and James River (1981, 1983). Annual egg production varied from 2.77 × 108 eggs in the Mattaponi River in 1980 to 2.69 × 109 eggs in the Pamunkey River in 1988. Results of contemporaneous surveys in 1983 indicated that egg production and biomass estimates were greatest on the Rappahannock and James rivers. Egg production estimates in Virginia are comparable to estimates for the upper Chesapeake Bay region and North Carolina. Our results indicate that an order-of-magnitude increase in female biomass was required to deposit the number of eggs observe...