Processes occurring during fish larvae stages as determinants of year-class strength in fish populations in the North-Western Mediterranean

The spatial and temporal mesoscale distribution pattern of fish larvae on the Catalan coast is closely linked both to mesoscale hydrodynamic mechanisms in the area, and to the distribution patterns of the remainder of zooplankton, including their predators and potential prey. Spatial coincidence with their most likely prey and the non-coincidence in time with their predators or potential competitors for the same prey are considered to be the mechanisms that most contribute to the survival of fish larvae in the area studied. The set of processes described which occur during the larval fish stages on the Catalan coast is one of the factors that may explain the fact that the number of adults captured has remained constant over recent years, despite the fact that the fisfiing effort has suffered few variations, that fishing power has increased (a greater number of ships with more efficient techniques), and that fishing techniques have diversified (there is now a tendency to exploit a greater number of species).