Changes in the fish community structure after the implementation of Marine Protected Areas in the south western coast of Portugal

Marine Protected Areas (MPAs) are increasingly being recommended as management tools for biodiversity conservation and fisheries. With the purpose of protecting the region’s biodiversity and prevent the over exploitation of marine resources, in February 2011 the MPAs of Ilha do Pessegueiro and Cabo Sardão were implemented in the “Parque Natural do Sudoeste Alentejano e Costa Vicentina “(PNSACV) Natural Park, south western coast of Portugal. In these areas, commercial and recreational fishing became prohibited. In order to evaluate the effects of these MPAs, the structure of its fish communities and of adjacent control areas without fishing restrictions were studied in 2011/12 (immediately after implementation) and 2013 (two years after implementation). A total of 4 sampling campaigns were conducted (summer 2011, winter 2012, summer 2013 and winter 2013) using bottom trawl and gillnets. Faunal communities from the MPAs (treatment) were compared with adjacent areas (controls) and changes evaluated with time. Results revealed significant changes on abundance, having this parameter a slight increase after the implementation of the MPAs. Also, significant differences were observed on the structure of the protected areas communities when compared with neighbouring areas where fishing was still allowed, even though the small amount of time elapsed. In addition, specimens of larger size occurred more frequently within Ilha do Pessegueiro MPA in the last year of the study. Despite the young age of these MPAs, changes on their fish communities’ structure are already visible after only 3 years of protection, showing that these management measures may promote sustainable exploitation of fishing resources as well as protect species with conservation interest, thus leading to a global biodiversity increase.