The Norwegian Sea
The Norwegian Sea Ecosystem is constantly changing, due to environmental and ecological influences. Both the temperature and the salinity in the Norwegian Sea have been over the long-term average within the last decade. In the past decade, the mackerel stock has increased both its geographic distribution during summer feeding and in stock size. The Norwegian spring spawning herring stock is currently at a level very close to its precautionary reference level, and in need of a strong year class to help maintain the stock at precautionary levels. Mesopelagic fish and their potential as a resource is a hot topic, and the Institute of Marine Research has initiated a project that aims and investigating the function and structure of the mesopelagic ecosystem, and methods for identifying, counting and catching these organisms.
The Institute of Marine Research plays a key role in the monitoring and management of the commercially important pelagic fish resources in the Norwegian Sea and the adjacent areas. The first-hand annual sales value of the fish stocks governed by the Norwegian Sea programme is ca € 550 mill. Of particular importance to the Norwegian economy and stakeholders are the stocks of Norwegian Spring Spawning herring, and Northeast Atlantic mackerel. This importance is reflected with considerable effort directed towards monitoring and assessing these stocks: There are several annual surveys for both stocks, and in addition, IMR conducts semi-automated mark-recapture program for both stocks that provides important time series that helps in stock assessment of these widely migratory stocks. The impact of IMR towards the sustainable management of these valuable stocks is high, and good monitoring facilitates conducting good research. However, the production of scientific publications about Norwegian Sea ecosystem has not been nearly as high as for the other adjacent ecosystems. The reason for this is most likely the historical tendency of the program effort concentrating on monitoring and advice instead of research, but there is large potential for high impact research, if resources will be directed to this purpose.
The Norwegian Sea programme has an extensive long-term monitoring program, where the Nordic Seas are covered in collaboration with other nations. Everything from plankton to whales is systematically monitored, together with the physical environment. Latest additions to our monitoring are the monitoring programme for sponges and corals, and the initiation of a project aiming at systematically collecting genetic samples to be use for monitoring of the short- and long-term changes in the genetic properties of the stocks and stocks’ genetic identity.
The activities in the Norwegian Sea programme have traditionally centred around monitoring and advice. However, lately some more weight has been put also on research. Understanding the ecosystem dynamics and trophic interactions is one of the areas where we are making progress, and out sea mammal monitoring programs have also resulted in many exciting scientific findings. Considerable amount of research on capture methods, particularly regarding pelagic capture, is taking place in this program.
The Norwegian Sea programme is heavily involved in the assessment and advice of all commercially important fish stocks in this area through ICES. Being the deepest among the Norwegian ocean ecosystems, Norwegian Sea program advices on deep sea-related questions nationally and internationally. Advice on commercial zooplankton harvesting is also carried out in this programme, and we deliver advice related to the harvesting of sea mammals.
The expansion of Northeast Atlantic mackerel to the Norwegian Sea during the summer feeding season has been drawing a lot of attention towards the changes in the distribution areas and migration routes that can be expected in the warming ocean. In addition to mackerel, also more southerly plankton species has been observed in the Norwegian Sea in the recent years, and many whale species show a more northerly distribution than before. Most likely these northward movements are only a prelude of a large-scale distributional changes that can be expected in the Northern ecosystems. One of the losers in this changing environment is hooded seal in the West Ice, which appear to be suffering from reduced feeding conditions.
The potential climate-induced changes in species distributions translate also to new dilemmas in the management of the widely distributed fish resources of the Norwegian Sea. National allocations of the total international quota are based on historical data on distribution of the stocks, but if the distribution changes, also the negotiations between the coastal states will likely become more challenging.