Most of the commercial fish stocks found in the Barents Sea stocks are at or above the long-term level. The exceptions are polar cod and Sebastes norvegicus. Also the abundance of blue whiting in the Barents Sea is at present very low, but for this stock only a minor part of the younger age groups and negligible parts of the mature stock are found in the Barents Sea.

Concerning shellfish, the shrimp abundance is relatively stable and above the long-term mean while the abundance and distribution area of snow crab is increasing.

Oceanic systems have a “longer memory” than atmospheric systems. Thus, a priori, it seems feasible to predict oceanic temperatures realistically and much further ahead than atmospheric weather predictions. However, the prediction is complicated due to variations being governed by processes originating both externally and locally, which operate at different time scales. Thus, both slow-moving advective propagation and rapid barotropic responses resulting from large-scale changes in air pressure must be considered.

Climate change may have a complex set of influences on both the flux and fate of contaminants in the Barents Sea. Increasing temperatures, changing wind systems and ocean currents, changing precipitation regime, melting sea ice, glaciers, ice-caps, and thawing permafrost, will all affect the transport, deposition, remobilization, and flux of contaminants between air and water, as well as environmental stability, ecosystem structure, bioavailability, bioaccumulation, bio-magnification, transformation,

Calanus glacialis in Barents Sea. Photo: Norwegian Polar Institute

Future prospects

Along with climate change, anthropogenic emissions of carbon dioxide (CO2) are causing acidification of the world oceans, because CO2 reacts with seawater to form carbonic acid. Due to the increased atmospheric CO2 concentration, the average pH-value of the surface waters of the global oceans has decreased from pH 8.2 to pH 8.1 since the onset of industrial revolution. This ocean acidification is extremely rapid in northern sea areas compared to other global oceans. It is expected that organisms

Sea ice research. Photo: Norwegian Polar Institute

Future prospects

Over the last 50 years, air temperatures have increased almost twice as fast in the Arctic than the global average. Models predict that air temperatures will continue to increase considerably, and summer sea ice in the Arctic is likely to disappear before the middle of this century and winter sea ice by the end of the current century (IPCC, 2013). Because of the complex dynamics of the Barents Sea ecosystem, and because the effects of climate change will interact with other major factors, such as