Zooplankton transport and distributions in the Gulf of Lions: Estimates from a Lagrangian model and optical remote sensing data

We develop a Lagrangian model to simulate the transport and distributions of zooplankton in the Gulf of Lions (GoL) coupling with the circulation model Symphonie and an individual based model (IBM). We consider zooplankton behaviour using a simple swimming pattern. Chlorophyll a concentrations retrieved from SeaWiFS data are used to estimate the food concentrations of the IBM. Individuals are released in the Rhoa¿ne river plume from May to October 2001 and are tracked for 40 days. Results suggest that passive individuals spread in the GoL but different patterns occur depending on the season and the initial depths of release. About 16% to a half of individuals remain in the GoL and the percentages of particles released at deeper layers are higher than those at upper layers. From June to September simulations with swimming behaviour increase the number of particles remaining on the shelf compared to simulations of passive particles. The zooplankton transport and distributions are strongly related to the hydrodynamic structures and zooplankton swimming behaviour connected with food.