The North Pacific Ocean is a sentinel region for signs of ocean acidification. Approximately 30-50% of global anthropogenic carbon dioxide (CO2) emissions are absorbed by the world’s oceans. Dissolving CO2 increases the hydrogen ion (H+) concentration in the ocean, and thus reduces ocean pH. Corrosive waters reach shallower depths more so there than in other ocean basins, especially in Alaska, and so biological impacts will likely occur earlier than in many other places. Ocean acidification reduces the calcium carbonate (CaCO3) saturation point, which stresses calcifying organisms by making calcification more difficult. The Alaska Fisheries Science Center research plan will focus on commercially important fish and shellfish species, their prey (calcareous plankton) and shelter (corals). Ocean acidification will likely impact the ability of marine calcifiers, such as corals and shellfish, to make shells and skeletons from CaCO3. Ocean acidification may also affect fish, marine mammal and seabird species through reduced abundance of calcareous plankton at the base of the food web. Species-specific studies of shellfish, calcareous plankton, corals and fish will be conducted to understand physiological effects (growth and survival). The CaCO3 content of calcareous organisms is not well known and a survey of shellfish, calcareous plankton and corals will be conducted to assess species vulnerabilities to ocean acidification. The results of the species-specific studies will be incorporated into population and ecosystem models to forecast population and ecosystem impacts. Bioeconomic models of Alaskan crab fisheries will be used to forecast fishery performance for a range of climate and ocean acidification scenarios.