Evaluation of average length as an estimator of exploitation status for the Florida coral-reef fish community

Abstract

Abstract Simulation and empirical analyses were conducted to evaluate the utility and robustness of average length (Lbar) of animals in the exploited population as an estimator of fishing mortality (F), and therefore as an indicator of exploitation status for Florida coral-reef fish. Simulation results showed that the Lbar estimator of fishing mortality was relatively insensitive to trends in recruitment, and demonstrated favourable properties for detecting statistical differences between sustainable and non-sustainable rates of exploitation. Rates of F estimated from fishery-dependent size composition data were comparable to F estimates from catch-and-effort time-series. Average length was also estimated from fishery-independent diver surveys for 22 species in the exploited snapper–grouper complex. A majority of snapper–grouper species are currently fished unsustainably in the Florida Keys, though overfishing appears most severe for long-lived, slow-growing fish.