Modelling the advection and diffusion of eggs and larvae of Northeast Arctic Greenland halibut

Abstract

In later years there has been considerable uncertainty on the recruitment of the northeast Arctic stock of Greenland halibut (Reinhardtius hyppoglossoides). The abundance of several year classes originally considered very low at 0-3 years age, are now considered higher than expected at the age of 6 or more. A possible explanation, raised earlier, is more northeasterly than expected distribution of the young fish by active migration and/or drift of eggs and Iarvae. The present work considers the transport and dispersion of eggs and larvae of Greenland halibut by numerical nod el ling. Current fields from a 3D baroclinic hydrodynarnic model are fed in to a Lagrangian particle tracking model. The particles arc released into the current at the spawning field along the shelf slope from Vesterålen to Bjørnøya (69-75"N). Vertically, the particles can follow a predefined depth-by-age curve or be kept, at a fixed depth, This model system is used for different years to examine changes in the drift pattern.