Factors structuring reproductive habitat suitability of Engraulis encrasicolus in the south coast of Sicily

Egg and larval abundance, obtained from annual summer cruises carried out in the Strait of Sicily during 6 years (1997 to 2002), was used to identify the spawning and retention areas of the anchovy Engraulis encrasicolus. Larval amino acid composition was used to analyse the nutritional condition of the larvae collected during the 2002 survey. As the anchovy spawns along the south Sicilian coast, but mainly in the north-west and middle parts of the coast, the higher number and larger size larvae in the south-east end of the Sicilian coast indicated that larvae were transported by the main branch of the Atlantic-Ionian Stream and retained in the south-east end of the Sicilian coast (Cape Passero). This retention process, however, did not always favour the nutritional condition of the larvae, because the larvae were not transported to an area with a higher primary production or with a higher stability. In 2002 larval amino acid concentration was higher in the spawning areas than in those areas where the larvae were transported to, indicating a lower nutritional condition of the larvae in the nursery areas. The lack of enrichment and concentration processes, and low primary production in this area which limited body growth rate may explain the low locally reproducing anchovy population in the south coast of Sicily.