Variability of the drift patterns of spring spawned herring larvae and the transport of water along the Norwegian shelf

Summary: A 3-dimensional baroclinic hydrodynamic model implemented for the North Sea, the Norwegian coast and part of the Norwegian and Barents Seas has been run for 18 years. This model has been used to study the Norwegian spring spawned herring larval transport from the main spawning areas at the coast of Norway. Currents from this model are fed into a Lagrangian particle tracking model to simulate the varying transports of larvae/juveniles. The simulations can explain much of the observed year to year variations in the distribution of herring larvae and juveniles, and significant larvae/juvenile transport into the Barents Sea seems to be a nessesary condition for good recruitment. In addition the model simulate a significant along-shelf larval mixing also observed in larval age investigations