Developing an individual based model for estimating biological reference points for the Gulf of Maine American lobster fishery

F_10% and F_0.1 are two fishing mortality rates used as potential biological reference points (BRP) in evaluating the status of American lobster fishery. The estimation of F_10% and F_0.1 may be straightforward for many fish species, but difficult for species like American lobster because of its complex life history and management regulations. In this study, we developed a seasonal sex-specific individual-based per-recruit model to mimic the American lobster life history and fishery in the Gulf of Maine. Egg-per-recruit, stock spawning biomass-per-recruit, and yield-per-recruit analyses were conducted for estimating F_10% and F_0.1, as well as sensitivity analysis for evaluating impacts of uncertainty in some key parameters. Six different measures of stock biomass/abundance were considered in the estimation of F_10% and F_0.1. This study shows that the individual-based simulation model is effective for the American lobster in estimating F_10% and F_0.1. The large difference in BRPs with different measures of stock biomass/abundance unveils the importance of knowing the selectivities and pitfalls associated with the different stock measures used in the lobster fishery management. A mis-use or mis-matching of stock biomass/abundance measures used in estimating BRPs and current fishing mortality may result in over- or under-estimating impacts of fishing on the lobster stock.