Book Description

The potential impacts on fish, fisheries and zooplankton of uncontaminated dredged material disposal at the proposed Norfolk (Virginia) disposal site was assessed through literature search and worst-case impact calculation. Emphasis was placed on analysis of the spatial and temporal distribution of ichthyoplankton and blue crab (Callinectes sapidus) larvae at the disposal site, and in the ocean waters adjacent to Chesapeake Bay. Available evidence indicated that the proposed site does not have any special importance to plankton, fish or fisheries. Most planktonic species have broad spatial distributions, and local impacts from dredged material disposal are therefore expected to have negligible effects on plankton populations. However, blue crab larvae and Atlantic croaker (Micropogon undulatus) larvae of the lower Chesapeake Bay and adjacent coastal ocean exhibit spatial distributions that may be determined in part by current patterns that retain the larvae in the vicinity of the Chesapeake Bay mouth. Therefore, the distribution of larvae available for recruitment may be spatially limited relative to most planktonic organisms. Based on available information on spatial distribution patterns, and using worst-case impact calculation, the possibility of a measurable effect of disposal on year-class strength of blue crab and croaker could not entirely be ruled out. Therefore, a period of restricted dumping during peak recruitment of blue crab and croaker larvae (September - October) was recommended.