Predicting and understanding effects of global climate change on ecosystems and fish production in oceanic systems is essential if we are to develop quantitative approaches to managing sustainable marine resources. We will address three hypotheses dealing with the environmentally induced variations in fish growth, regime shifts, and changes in energy cycling and structure of marine food-webs. We will use a combination of existing data sets, trophodynamic models and climate change scenarios to assess the changes in ecosystem structure and function of certain regions in the North Pacific. We will focus on herring as the target fish species and, geographically, we will focus on the North Pacific coastal and neighbouring oceanic regions. The collaborators include physical oceanographers, fisheries scientists and fisheries managers. Capacity building is an essential component of the project.