Effects of climate on marine ecosystem

Abstract

The spawning areas of the Arcto-Norwegian cod are located along the coast of mid and northern Norway, particulary in the Lofoten where up to 70% of the spawning occurs from mid March to early May. The larvae are carried northwards by the Norwegian Coastal Current to the nursery grounds in the Barents Sea. The year class strenght is largely determined during this period of pelagic free drift of 600-1200 km. Lateral spreading takes parts of the population out in the warmer Norwegian Atlantic Current and causes differences in the temperature experienced by the larvae. A three-dimensional baroclinic hydrodynamic model is set up for parts of the Norwegian Coast and the Barents Sea. Currents from this model move particles from the spawning grounds in the Vestfjord while keeping a record of the individual temperature histories. Temperature dependent growth is calculated using functional relationship know from ideal experiments. The model results are then compared to measurements.