American lobster adults live on the sea bottom, while lobster larvae are planktonic and drift with ocean currents. Because lobster larvae could drift over great distances from where they hatch to where they settle on the bottom, recruitment of lobsters to the fishery in a given area may depend on larval supply from other areas. This potential for connectivity between different fisheries areas poses a problem for management, as it means we cannot easily distinguish lobster populations or stocks. We are using a computer model of lobster biology coupled to a physical oceanographic model covering most of the American lobster's geographic range to estimate the potential large-scale connectivity (via larval drift) of different source-sink areas, including within and between fisheries management areas. We are also testing the sensitivity of potential connectivity and settlement predicted by the model to mortality and temperature-dependant larval development functions included in the biological model.