Model of Dredging Impact on Dungeness Crab in Grays Harbor, Washington

The effects of dredging on marine organisms have been an issue for several decades. Studies have shown effects on the composition of infaunal communities, including disruption and subsequent recolonization. Few attempts have been made to develop predictive models of dredging impacts on invertebrates. A few studies have focused specifically on Dungeness crab, primarily in Grays Harbor. The most recent of these studies has been aimed at quantifying crab entrainment and dredging morality rates. The intent of this study was threefold 1 to predict the numbers of crabs in various age classes that would be entertained and killed during the proposed widening and deepening of the Grays Harbor navigation channel 2 to use those predictions to forecast losses to the commercial fishery and 3 to modify both the dredge schedule and types of gear used in various areas reaches of the estuary in order to reduce predicted impact to crab.