STUDY OF A MEDITERRANEAN REEF FISH ASSEMBLAGE - COMPARISONS OF POPULATION-DISTRIBUTIONS BETWEEN DEPTHS IN PROTECTED AND UNPROTECTED AREAS OVER ONE DECADE

Differences in Mediterranean fish communities of two rocky coastal are as, one inside an integral marine reserve and the second outside the r eserve, near Banyuls-sur-Mer, France, were compared using underwater v isual census after a 12-year interval. In 1980, the community structur e in and outside the marine reserve was studied at two depths (Bell, 1 983). In 1992, we used the same methodology to assess if variations oc curred in this fish community between these two samplings. In both 198 0 and 1992, water depth affected the relative abundance of fish commun ities and the number of species was roughly maintained in both sites. However, there were several other important qualitative and quantitati ve variations in the fish fauna over this period: (1) The abundance of species has decreased in the integral reserve whereas it has been mai ntained outside the reserve; (2) Nine species are more abundant in the integral reserve and nine others are more abundant outside the reserv e. Among the species vulnerable to fishing, such as Labrus merula, Sym phodus tinca, Mullus surmuletus, Diplodus sargus, D. vulgaris, Scorpae na porcus, Oblada melanura, 6 of them are more abundant inside the int egral reserve and 4 others are more abundant outside; (3) The demograp hic structure of vulnerable species inside the reserve has changed: on ly the proportion of large fish (30 to 40 cm length) compared to mediu m (15 to 30 cm) and small (0 to 15 cm) fishes was higher in the integr al reserve. The prohibition of recreational and professional fisheries and scuba diving has the fish community in the integral marine reserv e in 1992 enhanced less than in 1980. The impoverishment of the fish d ensity in the integral reserve between these two periods is difficult to understand in reg;ard to the stability of the fish density outside the reserve. These results stress the need for a more regular and more extensive survey of the fish assemblage in and around the marine rese rve of Cerbere-Banyuls.