The Norwegian Sea ecoregion covers the Norwegian Sea and part of the Greenland sea, separated by a ridge.
The Norwegian Sea, the Greenland Sea and the Iceland Sea comprise the Nordic seas, which are separated from the rest of the North Atlantic by the Greenland–Scotland Ridge. The Norwegian Sea connects with the Faroes ecoregion to the southwest, the Icelandic Waters ecoregion and Greenland Sea to the west along the edge to the shallower Iceland Sea between the Faroe Islands, and northwards to Jan Mayen. To the south it borders the North Sea ecoregion, and to the east with the Barents Sea ecoregion. The Norwegian Sea ecoregion consists of two deep basins (between 3000 and 4000 m deep), the Norwegian Basin and the Lofoten Basin, separated by the Vøring Plateau (between 1000 and 3000 m deep).
The Norwegian Sea is a transition zone for warm and saline Atlantic waters entering from the south, and cold and fresher Arctic waters entering from the north. The major current, the Norwegian Atlantic Current, is a poleward extension of the Gulf Stream and the North Atlantic Current that acts as a conduit for warm and saline Atlantic water from the North Atlantic to the Barents Sea and Arctic Ocean.
This Ecosystem Overview focuses on the offshore ecoregion. Information relating to coastal elements is included where available and will be expanded in the future.
Key Signals
Ecosystem and environmental trends
- Water flowing into the Norwegian Sea from the south has been colder and fresher in 2016–2020 than previously, but overall cooling has been limited due to reduced heat loss driven by increased strength of westerly winds bringing in warmer air.
- Annual primary production has been higher (on average around 30%) in 2013–2019 compared to 2003–2012, possibly due to increased inflow of cold and fresh Arctic water containing elevated concentrations of nutrients.
- The biomass of major pelagic stocks in the ecoregion - Norwegian spring-spawning herring, mackerel (Scomber scombrus) and blue whiting (Micromesistius poutassou) - have all declined in recent years.
- Pelagically-feeding seabirds breeding along the Norwegian coast have declined substantially since the start of monitoring in 1980. Common guillemot (Uria aalge) is at high risk of extinction as a breeding species in the area.
- For marine mammals, a long-term shift in summer distribution from the Norwegian Sea to the Barents Sea has occurred in recent years. Pup production is at low level or declining for hooded seal (Cystophora cristata), grey seal (Halichoerus grypus) and harp seal (Pagophilus groenlandicus).
- Bycatch levels of harbour porpoise (Phocoena phocoena) population in coastal gillnet fisheries might exceed internationally adopted thresholds.
Pressures
The four most important pressures on the Norwegian Sea ecoregion, excluding climate change, are selective extraction of species, abrasion, underwater noise, and introduction of contaminating compounds (Figure 2). The first three of these pressures are linked to human activities in the region (fishing, maritime transport, and oil and gas production), while contaminating compounds are mainly introduced from sources outside the Norwegian Sea. The main pressures described below are defined in the ICES glossary of human pressures.
