Impact of interannual variability in hydrodynamic circulation on egg and larval transport of plaice Pleuronectes platessa L. in the southern North Sea

A realistic 2D circulation model of the southern North Sea was applied to simulate the interannual variability in dispersal (advection and diffusion) of plaice Pleuronectes platessa L. eggs and larvae from the spawning area in the Southern Bight of the North Sea towards the Dutch coastal nursery areas. The model is driven with daily varying current fields, which are the result of driving a general hydrodynamical model with realistic tidal and meteorological (wind) forcing for the period 1974–1981. Model simulations of plaice egg and larval transport are compared with observed larval concentrations near coastal nursery areas (Delta area and Wadden Sea). The model simulations show that: (1) the interannual variability in transport is large and of the same order as the year-to-year variations observed in larval concentrations near the nursery areas; (2) the interannual variability increases with increasing distance from the spawning area; (3) for the years in which larval estimates were available, the model predictions were positively correlated with observed estimates for the Marsdiep tidal inlet. This suggests that the variability in circulation patterns during the early pelagic stages in the open sea might be a key factor in determining year-class strength of plaice.