Planning for changing productivity and catchability in the Maine lobster fishery

Catches and biomass in the Maine lobster fishery have been at record levels in recent years despite sustained high exploitation rates. The fishery is almost completely based on lobsters just molting to legal size each year and thus is vulnerable to changes in environmental or ecological conditions that reduce recruitment. I use a bioeconomic model of the fishery that incorporates an empirically estimated vessel-level production function to evaluate how a reduction in recruitment might affect profitability and optimal effort levels relative to recent years. While large reductions in effort would almost certainly be required to maintain fishery profitability, the degree of effort reduction and the optimal seasonal distribution of effort and catch are sensitive to the time series of data used to estimate the production function. Because of the unidirectional upward trend in recruitment and catches, it is unclear whether changes in the production function are due to technological innovation or ecological change. However, the answer has important implications for the level of effort the fishery may be able to profitably support in the future.

► A bioeconomic model evaluates how reduced recruitment might affect optimal fishery effort.
► The fishery is vulnerable to changes in environmental conditions that could reduce recruitment.
► Large reductions in effort would be required to maintain fishery profitability.
► Optimal effort is sensitive to the time series of data used to estimate the production function.