Mesoscale distribution of fish larvae in relation to an upwelling filamentoff Northwest Africa

Fish eggs and larvae were studied in relation to an upwelling filament off Northwest Africa, near the Canary Islands, during August 1993. The filament was entrained around a quasi-permanent cyclonic eddy of diameter 100 km. T he sampled ichthyoplanktonic community was dominated by neritic larvae, 94. 2% of which were captured in the oceanic area. Horizontal distributions of neritic and oceanic larvae were strongly influenced by the oceanographic fe atures characteristic of the coastal margin. Neritic larvae were associated with upwelling and filament structures, while oceanic larvae were strongly excluded from these features. The results suggest that coastal upwelling a nd filaments are mechanisms of transport for neritic ichthyoplankton into o ceanic waters, that sardine larvae are good tracers of offshore movements o f upwelled waters, and that the cyclonic eddy functions as a larval nursery ground for neritic fish species. (C) 1999 Elsevier Science Ltd. All rights reserved.