A discrete time bioeconomic model is developed and used to derive supply curves for the open-access and the optimally managed fisheries. Supply curves are estimated based on data for the North Sea herring fishery. Different regulatory regimes in the fishery over the past two decades, both actual and theoretical, are evaluated with respect to effects on supply, stock level, and fishing effort. The results indicate that different regulations can have a substantial impact on the supply of North Sea herring. It is argued that the annual equilibrium supply can vary from zero in case the stock is driven to extinction under open access, to a sustainable annual yield of 690ï¿½700,000 tonnes.