Spatial management of the European hake Merluccius merluccius fishery in the Catalan Mediterranean: Simulation of management alternatives with the InVEST model

Abstract

European hake (Merluccius merluccius) is an important commercial fisheries species that shows growth overfishing, with catches basically focused on juveniles. This study assesses the benefit of closing a coastal area (an essential habitat for European hake recruits) to fishing, in addition to other alternatives of spatial management, compared with traditional, non–spatial management scenarios on fishing grounds exploited by the bottom trawl fleets of Blanes and Palamós (Province of Girona, NE Spain). We use InVEST, a spatially explicit model of intermediate complexity that simulates the bioeconomic effects of management measures for decision making. The sensitivity analysis of the model results shows the high influence of some parameters, particularly the parameterization of the recruitment submodel and European hake’s fecundity coefficients. The results are also examined in the light of uncertainty on migration parameters: in the two cases analysed (considering migration patterns or not), the results of the indicators (catch and revenues, abundance, recruitment and spawning stock biomass) were qualitatively similar and all show that the application of a restricted fishing area in one particular fishing ground (Vol de Terra) is the best management alternative. Its bioeconomic effects are comparable to a reduction of fishing effort of up to 20%. With high levels of ontogenetic migration, fishing on a second fishing ground (Cul de Rec – El Pas) should be restricted to enhance the biomass of the European hake population.