Larval drift of deep-sea shrimp Aristeus antennatus from limited areas of trawling

Abstract

The individual-based model can explore the connectivity of subpopulation of the deep-sea red shrimp Aristeus antennatus in the Northwestern Mediterranean Sea through larval drifts. The species is under a unique local management plan which limits the trawling activities of fish-ermen of Palamós (Spain). We used a Lagrangian framework with a three-dimensional hydro-dynamic model to evaluate the retention capacity of the shrimp stock under fishing re-striction, and therefore, the effictiveness of the local plan to expand the stock abundance. Modelled as passive particles, the larvae were retained for 44 % of them in the fishery area under restriction. This zone also received 27 % and 99 % larvae from another submarine can-yon and the inter-canyons area from higher latitude, respectively. When particles had the properties to ascend to the surface, through egg buoyancy, the larvae connected with a sub-marine canyon at lower latitude with 39.4 % of particles; and the Balearic Islands grounds with 40 %. The two drift paths were characterized by a drift in the superficial layer (0-5 m) and a drift in the subepilagic layer (5-200 m), respectively. Connectivity intensity with Bale-aric islands has slightly increased when spawning occured at the end of summer. The reten-tion or dispersion of larvae from the restrictive area of fishery depended mostly of the larval ecology. Above all, the vertical behaviour of the species larvae could influence the recruit-ment and determine the efficiency of the management plan