The effect of changes in temperature and food on the development of Calanus finmarchicus and Calanus helgolandicus populations

We studied the response in development times of Calanus finmarchicus and Calanus helgolandicus to changes in temperature and food conditions. Grazing experiments were performed at different temperatures for both species, and the results were implemented in a stage‐resolved zooplankton population model that predicted development times from biomass increments controlled by ingestion and metabolic losses. Predictions were validated against development data from the literature, and show that C. finmarchicus develops faster than C. helgolandicus below 11°C and slower above. The different relative development rates of the species are related to different temperature responses in ingestion rates. A temperature increase of 1°C to 2°C may have consequences for the relative contribution of C. helgolandicus and C. finmarchicus to the copepod community, and both seasonal and spatial displacements of the Calanus populations can be expected under climate change.