Impacts of climate change on commercial fish stocks in Norwegian waters

This report focuses on climate effects on productivity and distribution of fish stocks in Norwegian waters. If the temperature regime in these waters is altered, there is a high probability that this alone will result in changes in the distribution of some of the major commercial fish stocks. This again may influence the time spent in Norwegian EEZ and will be decisive for how much of the stock Norwegian fishermen can catch. The productivity of the fish stocks may also change due to increased temperature and changes in distribution and production of important prey species. First, some of the most important effects of climate change on the ocean are presented. These are mainly taken from the report of the Intergovernmental Panel on Climate Change. Second, the effects of these changes on the biota are discussed in general terms. Previous episodes of warming or cooling of the ocean are important to assess when considering future effects of climate on fish stocks. In this report, some of these episodes and resultant changes in fish stocks, are presented. Then, two possible scenarios of future climate change in Norwegian waters are suggested, and the likely effects on the most important commercial fish stocks are discussed. And finally, the effects of climate change on the occurrence of harmful algal blooms and aquaculture are discussed.