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

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 × 10 8 eggs in the Mattaponi River in 1980 to 2.69 × 10 9 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 observed during the 10‐year period. The occurrence of peaks in juvenile abundance appears unrelated to stock size, because above‐average recruitment was observed during years of high and low egg production. A substantial increase in spawning activity on Pamunkey River spawning grounds in 1987–1989 is attributed, in part, to the entry of 1982–1984 year‐class females into the spawning population. We conclude that successful 1982–1984 year‐classes and the implementation of more stringent fishing regulations have combined to increase present striped bass stocks in Virginia.