Abstract
Fish egg and larval assemblages, and the factors that drive them in the nearshore environment remain largely unknown. In this study, two sampling methods were used to assess the relative influences of space, time and environment on ichthyoplantkon communities at nearshore stations, near the Cerbère-Banyuls MPA (France), during spring and summer 2003. Resulting datasets were analyzed by variation partitioning, with redundancy analysis to estimate variances fractions based on adjusted R². A total of 42 environmental descriptors were considered for the analyses. The descriptor that best explained variance of the dataset were selected to build models. Analyses of the relative influences show that the environment conditions drive egg and larval density variations, specifically depth, currents and winds directions. However, time and space combined with environmental factors also contribute substantially to ichthyoplankton variability. The combined effect of space and environment is likely to be generated by the influence of the coast profile on ichthyoplankton from shallower water. At deeper stations, wind and current fluctuations bring about a combined effect of time and environment for eggs. These results strongly suggest that the nearshore area influence is between 25 and 30m depth and is separated from the inner continental shelf. We propose the hypothesis that the rocky shores ecosystem is favorable for coastal accumulation and/or retention of ichthyoplankton.