Examining the performance of alternative harvest regulations for short-lived taxa: A case study of Florida Bay scallop management

Abstract

The life history schedule of short-lived species compresses the temporal window available for harvest and exacerbates harvest timing decisions. For annual species whose populations are made up of a single year class, it is challenging yet essential to limit harvest to a level that will allow sufficient spawning escapement to sustain the population. Unexpectedly, intense harvest prior to reproduction could extirpate a population in a single season. Larger-scale commercial fisheries for annual or semelparous species are often managed using sophisticated pre-season abundance forecasts or in-season depletion estimates combined with intensive monitoring of catches and enforcement of catch limits. However, sufficient monitoring and harvest control are rarely feasible in recreational fisheries. We demonstrate the use of an age-structured simulation model to identify robust management regulations for recreational harvest season and bag limits applied to the Florida bay scallop fishery. We compared the outcomes of current harvest regulations with a suite of alternative harvest regulations in a recreational fishery for Florida bay scallops. To account for uncertainty in the stock status and dynamics of the fishery, we evaluated alternative harvest options across three levels of initial stock exploitation and two scenarios for future fishing effort. Our results show that biologically-informed regulations which allowed for more bay scallops to spawn prior to harvest, such as a later harvest season and daily harvest limit increasing over the season, performed well across all treatments and outperformed many of the current regulations when the initial stock state was more exploited, as well as when future effort doubled. These results suggest that (1) harvest regulations that more closely match the biology and life history are likely to perform better for short-lived, annual taxa than simpler regulations that may not explicitly consider these factors, and (2) simpler regulations can perform well, but require precise, annual monitoring to prevent potentially catastrophic overharvest or costly underutilization.