Management Strategy Evaluation for the Common Spiny Lobster, Palinurus elephas (Fabricius, 1787), Stock in Tunisia

Abstract

The common spiny lobster, Palinurus elephas (Fabricius, 1787), fishery in Tunisia has been overexploited. This species is currently managed by temporal closures, minimum legal sizes of landings, and the prohibition of catching berried females. This study aims to develop management procedures (MPs) based on the surplus production model to set total allowable catch (TAC) as a management action for the common spiny lobster. Ten MPs ranging from conservative to more relaxed management procedures were evaluated within a management strategy evaluation (MSE) framework. Several scenarios of the operating model were considered to account for uncertainties. Five performance measures were used to evaluate MPs to identify the management strategies that can achieve the prespecified management objective of recovering the stock size as a priority and ensuring high and stable catches. The results of the MSE showed that the conservative management strategies with the highest control points performed well in terms of management objectives with a probability of biomass exceeding the reference point of higher than 90 % but yielded in the lowest catches. On the other hand, relaxed threshold-based management strategies failed in achieving management objectives with 20 % probability of being below the limit reference point. These MSE results also highlighted the trade-off between conservation and catch performance objectives and showed that some moderate management strategies balanced these objectives efficiently.