Marine protected areas (MPAs) are increasingly envisaged as a tool to manage coastal ecosystems and fisheries. Assessment of their performance with respect to management objectives is therefore important. A number of MPAs provided conservation benefits for fished species. Observed benefits do not apply to all species at all times, and responses to protection are also highly variable among fish taxa. Among the many empirical studies on marine reserves, only a few designs considered 'before and after data' and spatial variation. In this paper, we are interested in assessing the effect of a no-take reserve on the reef fish assemblage in a northwestern Mediterranean example. Data were obtained from a three-year survey using underwater visual censuses (UVC), before and after MPA establishment. Permutational multivariate analysis of variance (PERMANOVA) and multivariate regression trees (MRT) were used to evaluate the effects of reserve protection on the reef fish assemblage, while accounting for habitat. Modelled biological responses were abundances and diversity indices calculated at different levels of the assemblage. Significant effects were found for many of these metrics. In addition to PERMANOVA, univariate models provided more insight into the magnitude and direction of effects. The most sensitive metrics were related to large species and species targeted by fishing. These results may be used to choose the metrics that are more suitable as community-based indicators of MPA impact in the perspective of monitoring programs.

in October-November, and D. vulgaris in 2 pulses, the first in November-December and the second in January-February. Settlement intensity varied spatially, temporally, and among species. At a small spatlal scale (with~n site), settlement intensity varied between stations and particularly between years. At a large spatial scale (among sites), settlement intensity varied among sites, with Marseille and Girona generally experiencing higher settlement than other sites. No difference in settlement intensity was observed between protected and unprotected areas The settlement of D. sargus was higher in 1994 than in 1993 and 1995 at all sites, suggesting the influence of meso-scale hydroclimatic conditions on the settlement success of t h~s species. The settlement of D. vulgaris was higher in 1993 in the western part of the NW Mediterranean, and in 1994 in the eastern part. No consistent spatial trend over t~m e was seen for D. puntazzo. Thus, settlement intensity of Diplodus species to nearshore habitats in the NW Mediterranean exhibited high year-to-year variations at both local and regional scales.

Diffcrcnces in Mediterranean fish communities of two rocky coastal arcas, one inside an integral marine reserve and thc second outside the reserve, ncar Banyuls-sur-Mer, France, wcrc compared using underwater visual census aftcr a 12-year interval. In 1980, thc community structure in and outside the marine reserve was studied at two depths (Bell, 1983). In 1992, WC uscd the same methodology to asscss if variations occurred in this fish coinmunity between these two samplings. In both 1980 and 1992, water depth affected the relative abundance of fish communities and the number of species was roughly maintained in both sites. However, there were several other important qualitative and quantitative variations in the fish fauna over this period: (1) The abundance of specics has decreased in the integral rcscrve whereas it has been maintained outsidc the reserve; (2) Nine species arc more abundant in the integral rcscrvc and nine others are more abundant outsidc the reserve. Among the specics vulnerable to fishing, such as Lubrus merulu, Symphodus (inca, Mullus surmuletus, Dip1odu.c. sargus, il. vulgaris, Scorpavnu porrus, Ohlada melanuru, 6 of them are more abundant inside the integral reserve and 4 othcrs arc more abundant outside; (3) Thc demographic structure of vulnerable spccics inside the reserve has changcd: only Ihe proportion of large fish (30 to 40 cm length) compared to medium (15 to 30 cm) and small (0 to 15 cm) fishes was higher in the integral reserve. The prohibition of recreational and professional fisheries and scuba diving has the fish community in the integral marine reserve in 1992 enhanccd less than in 1980. The impoverishment of the fish density in the integral reserve between these two periods is difficult to understand in regard 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 reserve of Cerbère-Banyuls.