Validation of an Eulerian population model for the marine copepod Calanus finmarchicus in the Norwegian Sea

• A stage resolving Eulerian model of Calanus finmarchicus is presented and validated.
• The Calanus model is integrated in the physical–biological ocean model SINMOD.
• Focus is on validation of Calanus abundance in the Norwegian Sea.
• Good agreement is seen in abundance and spatial and temporal variability.

Calanus finmarchicus is an important zooplankton species in the Norwegian Sea, as a dominant food organism for pelagic fish larvae, and a potentially large source of marine lipids and proteins. Its position in the marine food web also makes it an important model species in assessing the risk posed by oil spills in the Norwegian and Arctic Seas. In this study, an Eulerian population model for C.finmarchicus, coupled to the physical and ecological model SINMOD, is presented. The model includes the full life cycle of C. finmarchicus with a representation of all developmental stages. The model has been validated against field measurements made in different areas of the Norwegian Sea in 1997 and 1998. The model displays geographical and temporal distributions of development stages that is in line with observed patterns. When comparing time series for selected regions, we see a high degree of variability both in the field samples and model output. On average, the model deviations are near half of the summed variability of the field data and model estimates.The model has applications within assessment of ecological production, and the potential for harvesting in the Norwegian and Arctic Seas, but in combination with other models, also for the assessment of ecological effects of oil spills and other types of pollution.