Distribution and Size Structure of Sardine Larvae (Sardina pilchardus) Along the South Area (21-26°N) of Atlantic Coast of Northwest Africa in Autumn 2007

The Atlantic coast of the Northwestern Africa is characterized by high productivity based on seasonal and permanent coastal upwellings and depending abundant small pelagic fishes including Sardina pilchardus.  In November 2007, we conducted an oceanographic survey along the Atlantic coast between Cape Boujdor (26°N) and Cape Blanc (21°N).  Sardine (Sardina pilchardus) larva was dominant (89 % of total), and the majority were smaller than 6mm TL. Bimodal distribution of sardine larvae (>3000 ind.10m-²) were identified around Dakhla in North (25°N) and in South (22°30'N).  Spatial match of larvae to the thermal and food condition were statistically compared between these two concentrations. Observed difference in the potential growth and survival conditions were interpreted in relation with both hydrodynamics and biological richness of the environment.  In the study area, a distinct upwelling filament has been observed, and this filament is responsible of larval transport.  The hypothesized drifting and retention pattern provides favorable environments for the larval development of the small pelagic species, sustaining ecosystem and Moroccan fisheries.