Effect of a large-scale and offshore marine protected area on demersal fish assemblage in the Southwest Atlantic

ALEMANY, D.; IRIBARNE, O.; ACHA, E. M.

Mar del Plata

Conferencia; CERF 2012 The Changing Coastal and Estuarine Environment: A Comparative Approach; 2012

Coastal and Estuarine Research Federation

The decline of marine resources is of global concern and very restrictive rebuilding measures, as large-scale fishery closures, are being implemented. In that sense, the establishment of marine protected areas (MPAs) seems to be one of the potential solutions to this ecological crisis. There are few extensive and offshore located MPAs in the world ocean and their performance is still debated. We evaluated the effects of a large-scale offshore located MPA in the SW Atlantic Patagonian shelf (43ºS 63ºW) on demersal fish assemblage. Compliance of the Patagonian MPA was assessed analyzing eight years of satellite vessel monitoring system (VMS; 2000-2008) data which shows true compliance and fishing effort concentrated near protection boundaries. MPA’s effects were studied employing a five years database collected by a scientific research vessel in protected and fishing locations, before and after the MPA establishment. We analyzed 152 scientific trawling stations using multivariate analysis on fish assemblage structure and on fish abundance, discriminating target and non-target species, and on mean size and proportion of juveniles of the target species (the Argentine hake, Merluccius hubbsi). MPA effects identified were increasing trends of abundance of the demersal fish assemblage as a whole, of the target and of the non-target species. Moreover, increases in hake juveniles’ size and in the proportion of 2+ juveniles were detected inside the MPA. Despite MPA effects did not vary consistently through time the positive effects we detected result promising regarding offshore, large-scale MPAs.