Meteorological and oceanographic factors influencing Engraulis encrasicolus early life stages and catches in the Gulf of Cádiz

Abstract

The meteorological and oceanographic factors that have clear influence on the distribution of Engraulis encrasicolus eggs and larvae in shelf waters of the northeastern sector of the Gulf of Cádiz has been analyzed. Very high concentrations of anchovy eggs and larvae were found in this area during the spawning period (from March 2002 to September of 2002). The shallowness of the water column, the influence of the Guadalquivir River, and the local topography favor the existence of warm and chlorophyll-rich waters in the area, thus offering a favorable environment for the development of eggs and larvae. However, during spring and early summer intense easterlies were observed to cause a decrease of the water temperature by several degrees. Easterlies generate oligotrophic conditions in the area, and their persistence forces the offshore transport of waters over this portion of the shelf, advecting early life stages away from favorable conditions. These negative influences on the development conditions of anchovy eggs and larvae can impact on the recruitment of this species in the Gulf of Cádiz. Therefore, inter-annual fluctuations in the duration of intense easterly winds is analyzed and discussed in connection with anchovy catches.