An analysis of rocky coastal eastern Mediterranean fish assemblages and a comparison with an adjacent small artificial reef

The fish assemblages of two natural rocky habitats and a small artificial reef on the Mediterranean coast of Israel were studied. A total of 54 species belonging to 23 families was collected. Species similarity was greater between years at the same habitat than between sites. All habitats studied had a similar species diversity, but species richness and biomass were higher on the artificial reef. The results indicate that erection of artificial reefs on Israel's relatively barren inshore continental shelf could considerably increase the local fish production. Red Sea immigrant species were found to constitute only 7.4% of the collected fish, but on average, they contributed > 20% of the standing crop. During this study, a new Red Sea immigrant, the sweeper Pempheris vanicolensis Cuvier and Valenciennes, 1831, which was absent during the years 1975-1976, colonized the region. It was first observed in the study area in 1979, and by 1983 had become the most abundant species, constituting 44.3% of the biomass collected. The results indicate that this species may have occupied an "undersaturated niche", as it does not appear to affect the abundance of the pre-existing fish species. Recolonization of the defaunated artificial reef site was monitored, and 1 yr later the newly established assemblage was collected. The recolonization process and various factors influencing recruitment are discussed.