Contributions of a conservation measure that protects the spawning stock to drastic increases in the Gulf of Maine American lobster fishery

V-notching, a conservation measure intended for the protection of mature female lobsters, has been hypothesized to have contributed to the dramatic increase in American lobster Homarus americanus landings and stock biomass in the Gulf of Maine. To evaluate the impact of this conservation measure, scenarios examining different v-notching compliance rates and vnotch definitions were simulated using an individual-based lobster simulator with different re - cruitment dynamics scenarios. In the model, v-notching with a high compliance rate and a strict de - finition of the 'notch' increased spawning stock biomass by 33-632%. Without a stock- recruitment relationship, v-notching with high compliance and a strict definition decreased landings by 2%. With a weak or strong stock-recruitment relationship, v-notching with high compliance and a strict definition increased landings by 33-85%. Without a high v-notching compliance rate (i.e. 90 or 100% compliance) or a strict definition of the notch, the lobster stock and fishery would not have experienced such large positive increases in biomass and landings. These results suggest that input controls, such as protecting the spawning stock, can provide significant benefits to both the fish population and fishery. The framework proposed in this study can be extended to evaluate the protection of spawning females in other fisheries.