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Study of a Mediterranean reef fish assemblage. Comparisons of population distributions between depths in protected and unprotected areas over one decade

TitleStudy of a Mediterranean reef fish assemblage. Comparisons of population distributions between depths in protected and unprotected areas over one decade
Publication TypeJournal Article
Year of Publication1995
AuthorsDufour F, Galzin R, Jouvenel J-Y
JournalAquatic Living Ressources
Keywordsassemblage, census, Cerbère-Banyuls, comparison, density, depth, Diplodus sargus, Diplodus vulgaris, distribution, fauna, fish, fish abundance, fish assemblage, fish density, fishery, France, integral reserve, labridae, Lubrus merulu, marine protected area, marine reserve, Mediterranean sea, methodology, mullidae, Mullus surmuletus, no-take area, Oblada melanura, population, protection effectiveness, reef fish assemblage, reserve effect, Scorpavnu porrus, scuba-diving, serranidae, sparidae, Symphodus tinca, unprotected area, visual census, western Mediterranean

Differences in Mediterranean fish communities of two rocky coastal areas, one inside an integral marine reserve and the second outside the reserve, ncar Banyuls-sur-Mer, France, were compared using underwater visual census after a 12-year interval. In 1980, the community structure in and outside the marine reserve was studied at two depths (Bell, 1983). In 1992, WC used the same methodology to assess if variations occurred in this fish community 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 reservc and nine others are more abundant outside the reserve. Among the specics vulnerable to fishing, such as Lubrus merulu, Symphodus tinca, Mullus surmuletus, Diplodus sargus, D.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 changed: only the 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 enhanced 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.

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