The Calanus complex contains four species (Calanus helgolandicus, C. finmarchicus, C. glacialis, C. hyperboreus) that dominate both warm and cold water herbivore communities along the North Sea to Arctic Ocean axis. Despite their morphological similarities, these species exhibit important differences in behaviour, size, fat metabolism and deposition, reproduction, overwintering, diapause, diet, susceptibility to predation, etc. It is not known precisely why a given Calanus species succeeds in one environment and not in another - arriving at a better understanding of this will allow us to better predict how the herbivorous communities of the northeast Atlantic will change in response to global warming. We propose to examine the underlying mechanisms and potential long term impact of changes in the Calanus complex at the three predefined adult and larval fish feeding grounds, and in the north-east Atlantic in general. We will do so by using historical data, process studies, experimental studies and ecosystem modelling.
This Strategic Institute Program will enable IMR to give better advice on the ecosystem effects of climate change. In particular changes in the dynamics at lower trophic levels, being the part of the ecosystem where the most pronounced climate induced changes are expected. New knowledge on Calanus species interactions and climate effects will improve our abilities to give advice under the ecosystem approach to fisheries management. Improved model simulation capabilities will enable forecasts of Calanus distribution and production in their present and new areas under a changing climate, with particular focus on feeding areas and spawning sites of commercial fish stocks.