MICROHABITAT REQUIREMENTS FOR SETTLEMENT OF JUVENILE SPARID FISHES ONMEDITERRANEAN ROCKY SHORES

Microhabitat attributes were characterized for recently settled juveni le fishes in six species of Sparidae (Diplodus annularis, D. puntazzo, D. sargus, D. vulgaris, Oblada melanura, and Sarpa salpa) on the rock y shore near Marseille, French Mediterranean coast. Depth, slope, type of substratum, biotic cover and hydrodynamic conditions were recorded wherever sparid recruits occurred. Juvenile Diplodus annularis settle d in Posidonia oceanica seagrass beds at 5-8 m deep. The five other sp arid species recruited in very shallow water (<2 m). D. puntazzo, D. s argus and D. vulgaris were observed in sites presenting a gentle slope with coarse sand, gravel, pebbles or boulders. Sarpa salpa was less d ependent on slope for recruitment, but was always associated with macr oalgae. Oblada melanura settlement occurred on rocky areas with variou s slopes, and was favoured by the presence of overhangs. When growing, juvenile sparids extended their home range vertically into deeper zon es, and laterally in more exposed areas. Time partitioning in the use of suitable microhabitats for recruitment was observed for some specie s. Juveniles of Diplodus puntazzo and D. vulgaris shared the same site s from March to May, both exhibiting relatively low abundances. D. sar gus recruited in far higher abundance in the same sites from May to Se ptember. Specific improvements in coastal man-made structures (harbour s, artificial beaches) are suggested in order to increase the recruitm ent of some littoral fish species.