Effects of a marine protected area on fish assemblage associated with Posidonia oceanica seagrass beds: temporal and depth variations

This study describes the changes in the structure of the fish assemblage associated with Posidonia oceanica meadows after the establishment of a marine protected area. The survey of the ichthyofauna in the Marine Reserve of Tabarca Island was carried out by visual censuses with SCUBA. Inside and outside the reserve was sampled six times at random from summer 1997 to summer 1999 and in three different depths (1, 5 and 15 m) by applying transects of 150 · 5 m over the P. oceanica meadows. The data were analyzed with multivariant method-ologies and with analysis of variance. The most represented families in number of species were the sparids and labrids. Mean abundance, biomass and number of species were higher inside the reserve in all studied periods. Inside the marine protected area, these variables decreased as depth increased; outside the protected area the pattern was the opposite, reaching the maximum at 15 m