Selective Tidal Transport of North Sea Plaice Larvae Pleuronectes platessa in Coastal Nursery Areas

Abstract

The transport of plaice larvae from the open sea towards shallow, mainly inshore, nursery areas along the North Sea coast was studied for 5 years in the Easter Scheldt and the Wadden Sea. Metamorphosing larvae (stages 4 and 5) entered the nursery areas in March and April. Larva density was significantly correlated with the density of 0-group plaice at the end of the following summer. Significant factors determining the larval densities were date of sampling, location, tide, depth, and did period. Larvae usually were most abundant in the bottom stratum, but during nighttime flood tides they moved into midwater and surface strata. Flood catches exceeded the ebb catches of pelagic larvae for all stations. The results suggest that plaice larvae accomplish passive but selective horizontal transport by swimming up from the seabed during flood tides and remaining on the seabed during ebb tides.