During the last decade the concern regarding environmental effects of the offshore industry has shifted from effects of drilling discharges on benthic communities, towards a stronger focus on the water column and effects on the pelagic ecosystem. At the same time, oil and gas development is expanding in the Norwegian and Russian sectors of the Barents Sea. In this regard, a project has been initiated to look at responses of especially Calanus spp. and other copepod species to long-term, sublethal exposure to selected offshore discharges and discharge components, as well as accidental oil spills. Calanus spp. is ecologically the most important zooplankton species along the Norwegian shelf and in the Barents Sea. A laboratory based facility for culture through several generations is being developed through this project. In addition, the impact of oil compounds on the cold-water and arctic Calanus species-complex will be examined by carrying out a series of laboratory (some at Ny Ålesund) and ship based experiments. The response parameters will include both behavioral (feeding, mate finding, avoidance) and physiological (mortality, egg production, development rates, oxygen consumption and assimilation efficiency) parameters. The ultimate outcome of this research is expected to be a supporting instrument for ecological risk assessment of offshore discharges, which is highly relevant both to the North Sea, the mid-Norway shelf and the Barents Sea.