Incorporating space into models of the Chesapeake Bay blue crab population

Few models of blue crab population dynamics have accounted for the spatial aspects of crab life history in their formulations. Here I develop a spatially-explicit model of the Chesapeake Bay blue crab population that reflects our understanding of the general life history. Best available estimates of growth, mortality and fecundity were used. Currently, we lack empirical data on which to base estimates of movement probabilities. Thus, movement probabilities were based on the relative area of each region. The model results show that the current pattern of exploitation in blue crab is likely not sustainable and needs to be reduced substantially. The model appears relatively insensitive to the estimated probability of survival during early life history. Moreover, variation in the proportion of crabs that recruit to the fishery at age-1 appear to have little impacts on projected rates of population growth. Model results also show that restriction of a winter dredge fishery in the lower Chesapeake Bay is not sufficient to ensure a sustainable pattern of exploitation. Until further empirical data are available to improve accuracy, the model serves as a useful tool for exploring consequences of different spatial distributions and patterns of exploitation.