Estimation Of Oyster, Crassostrea Virginica, Standing Stock, Larval Production And Advective Loss In Relation To Observed Recruitment In The James River, Virginia

Standing stock and demographic data for oysters, Crassostrea virginica, in the James River, Virginia are used to generate spatial estimates of egg production on a reef-specific basis. Subsequent estimates are made of losses related to density-dependent fertilization, natural mortality in the plankton, advective loss related to estuarine circulation, availability of substrate (both absolute amounts and after occlusion by fouling organisms), limited competency of pediveligers to metamorphose, and post settlement mortality to an age of 4 wk post metamorphosis. Reef-specific egg production is highly variable on a per unit basis within the James. In all reef systems fertilization losses approach two orders of magnitude, in some instances higher than estimated losses to advection over a 21-day development period. The combination of limited substrate availability compounded by substrate fouling suggests that increasing substrate availability at the rime of settlement would strongly facilitate an increase in population size. Final estimates from sequential calculations of surviving juvenile densities agree within one order of magnitude with field observations