Environmental determinants on fish post-larval distribution in coastal areas of south-western Mediterranean Sea

Light traps have been used worldwide to sample pre-settlement stages as a good estimator of larval availability and distribution to nearshore habitats; however few studies have been performed to date in temperate environment, such as Mediterranean rocky reefs. Here we describe the spatial and temporal variability of post-larval assemblage in the south-western Mediterranean Sea using light traps, and the effects of environmental variables on their abundances. We sampled 2 coastal localities with 9 light-traps for 2 consecutive nights during 13 months. Post-larval occurrence presented a seasonal pattern in which greater abundances and richness occurred during summer and autumn months. Sea surface temperature, currents and winds were the most important variables related to larval abundance. Important spatial differences in terms of diversity and post-larval abundances were found in an area protected from fishing. Although not tested, we suggest that 1) bottom morphology, 2) presence and distribution of habitat types in coastal areas, including those of adults, 3) local oceanographic conditions, and 4) direct and indirect MPA effects, may influence post-larval distribution, resulting in fine-scale spatial differences. These results reinforce the need to undertake further studies on early life stages of fishes to better understand the dynamic of coastal fish populations.