Estuarine Mysids as key prey for anchovy juveniles

Trabajo presentado en la 54th Estuarine & Coastal Sciences Association (ECSA 54 Coastal systems under change: tuning assessments and management tools), celebrada en Sesimbra (Portugal) del 12 al 14 de mayo de 2014.Previous studies on feeding habits of European anchovy Engraulis encrasicolus, carried out in open sea, described it as a strictly zooplanktivorous species, with copepods their main prey from larvae to adults. Nevertheless the analysis of the stomach contents of a total of 1836 individuals (from 18 to 131 mm total length) collected monthly (from February 1998 to January 1999) at the Guadalquivir estuary (SW Spain) revealed that estuarine mysids play an importan! role in their diet. lnside the estuary, the smallest individuals analysed (postlarvae) fed mainly on copepods, but as they grew into juveniles they shifted to mysisd. In fact, estuarine mysids representad 76% of dietary composition, in terms of biomass, of juveniles (total length > 40 mm), being Mesopodopsis slabberithe main prey species (46%). During last16 years, from June 1997 to date, abundance of anchovy and mysids have been monitored by monthly sampling in the estuary. This time series has pointed out the role of the estuary as an importan! nursery ground for anchovy. The seasonal coincidence of maximal anchovy and mysid densities suggests that load availability may be a principal factor influencing that nursery function.N