Substrate use and temporal pattern of recruitment in juvenile fishes of the Mediterranean littoral

The microhabitat use and seasonality of the juveniles of 24 littoral species in the north-west Mediterranean Sea were studied between March 1993 and March 1994. Labrids species recruit during summer months, from July to September, whereas sparids recruit at different times of the year. Canonical correspondence analysis revealed that the species recruit in well-defined habitats. Sparid species recruit primarily in the shallowest zone (0 to 2 m), and most of them prefer varied bottoms (sand, gravel or small blocks). Some species of the genus Diplodus have similar habitat requirements, but show a clear seasonal segregation, with each species occupying successively the same zones at a different time of the year. Labrid species show a high degree of seasonal and spatial co-occurrence, and are normally found on rocky substrates with high algal cover. Two species (Mullus surmuletus and Symphodus cinereus) recruit mainly in Posidonia oceanica beds, while other species (Serranus cabrilla, Coris julis, Symphodus ocellatus, S. rostratus), are abundant in both seagrass beds and on rocky substrates.