10. Regional Summaries: Pressures and Biodiversity at the Level of the OSPAR Regions

Regional Summaries

Arctic Waters

The Arctic Waters (Region I) constitute approximately 40% of the OSPAR Maritime Area. This is the most northerly OSPAR Region, characterised by a harsh climate and ice coverage, with exceedingly rich marine ecosystems. Despite low population density (total population of 2,6 million), major commercial activities such as offshore petroleum production and fisheries are in operation. Petroleum production mainly takes place in Norwegian waters, whereas fisheries are significant in Iceland, the Faroe Islands, Norway and elsewhere in the Region.

Six species of fish support the major fisheries in the Nordic and Barents Seas: cod, saithe, haddock, blue whiting, herring and capelin; major spawning grounds for these and other commercially important fish exist along the continental shelves of the Nordic countries. Though many types of fishing occur, pressure from bottom trawling is lower than in most other OSPAR Regions. Finfish aquaculture has been an important industry here, with expansion planned for future years, including into offshore environments. Increased shipping and oil and gas activity, for example in the Barents Sea, may bring further pressures in the coming decade. Deep seabed mining in the Region is also being considered. A growth in tourism activity may increase pressure on sensitive habitats.

The QSR 2023 highlights numerous biodiversity issues in the Arctic Waters Region. Foremost among these is climate change and the effect that warming and loss of ice, along with ocean acidification, are having on marine ecosystems. The European Arctic is one of the most abundant seabird regions in the world with a breeding population of more than 25 million, so the importance of this region for marine birds cannot be overstated. The Marine Birds Thematic Assessment describes the climate change impacts on surface feeding, water column feeding, and benthic feeding birds – all in ‘not good’ status. Hazardous substances are also affecting biota in this region, with strong evidence that PCBs and mercury are increasing in some marine mammals like polar bears, ringed seals and narwhals as a consequence of environmental changes at local scale. At a larger scale, previous (e.g. whaling) and current (e.g. climate change) pressures result in the blue whale and bowhead whale populations being in ‘not good’ status; whereas fisheries by-catch is impacting small toothed cetaceans. Non-indigenous species are spreading and are expected to expand northwards with climate change. Waterborne nutrient inputs and other substances coming from aquaculture warrant increasing attention, especially as aquaculture expands in this region; this may be affecting pelagic habitats as well as food webs.

Greater North Sea

The Greater North Sea (Region II) is an area of intense activity, influenced by major population centres, intensive agricultural land use, energy development, fishing, and tourism / recreation, particularly in the southern portions. The presence of major ports in the area results in high pressure from shipping, as well as widespread commercial fishing, with bottom trawls deployed over 73% of the ICES ecoregion (OSPAR Region II except the English Channel) in 2018. Salmon aquaculture is a significant and still expanding industry on the Norwegian coast. Most aggregates extraction in the North-East Atlantic occurs in the Southern North Sea and the English Channel. Oil and gas production is widespread in the Northern North Sea, and gas production occurs in the Southern North Sea. In the past decade, offshore wind developments have increased in the Southern North Sea and the Skagerrak and Kattegat, and major expansion of offshore wind energy will be a key issue for the region in the coming decade.

The QSR 2023 found that the cumulative pressures from these activities affect marine ecosystems and biodiversity in significant and measurable ways. Fishing activities, particularly trawl fisheries, have degraded benthic habitats and caused food web imbalances. Increasing amounts of marine litter on the seafloor may be adding additional pressures through smothering and entanglement, and the ambient and impulsive noise levels assessed for the first time by OSPAR indicate serious pressures from shipping and seismic surveys in this Region. Although eutrophication has decreased in some (but not all) catchments and marine areas in this region, nutrient imbalances in concert with climate change effects have impacted phytoplankton production and therefore put additional stress on the food webs. Localised but persistent areas of oxygen deficiency also exist, and hazardous substances resulting from intensive human activity continue to be a problem. All these problems affect biodiversity, ecosystem services delivery and human wellbeing.

The net effect of these cumulative pressures on biota in this Region has been negative, resulting in ‘not good’ status for many common species as well as those on the OSPAR list of threatened and declining species. Among marine birds, the majority of assessed surface feeders (e.g. gulls, shearwaters, skuas); water column feeders (e.g. grebes, cormorants, puffins); benthic feeders (eiders and scaups); and wading feeders (e.g. plovers, sandpipers, egrets) have been found to be in poor status - meaning that less than 75% of their populations were assessed as being in good status. On the other hand, grazing birds such as geese were found to be in good condition in this region. Among marine mammals, small toothed cetaceans and most seals (with the exception of the grey seal) were found to be in ‘not good’ status. Fisheries by-catch is impacting small toothed cetaceans. The picture for commercial and sensitive fish species is mixed in this region; however, none of the groups (coastal, demersal, deep sea and pelagic) reached the threshold of 80% of populations being in good status. The assessments of benthic habitats and food webs show that disturbance and extraction have had significant impact – benthic diversity is particularly poor in inshore areas of this region. Finally, phytoplankton and zooplankton productivity in this Region are subject to significant change.

Celtic Seas

The pressures associated with fishing, shipping, coastal development, tourism, and agriculture are widespread in the Celtic Seas (Region III) although the Region is not as intensively used as the Greater North Sea. Mobile bottom trawls were deployed over almost 45% of the ICES ecoregion in 2018. Finfish and / or shellfish aquaculture is important in the United Kingdom, Ireland and France. Energy production (oil and gas, and renewable energy) takes place and, like the situation in the Greater North Sea, significant future expansion of offshore wind energy is projected, most notably in the Irish Sea. However, eutrophication is not increasing and assessed hazardous substances are declining. The rate of NIS introductions seems to be declining in the Region.

The QSR 2023 has identified a number of region-specific biodiversity issues. Small toothed cetaceans were found to be in ‘not good’ status, with fisheries by-catch a cause for concern. For birds, as with the observations made for the Greater North Sea, the status of surface feeders, water column feeders, benthic feeders and wading feeders was not good, while grazing feeders were in good status. For fish, the majority of both commercial and sensitive fish species that were assessed as being in ‘not good’ status; this applied particularly to coastal species. The pelagic and benthic habitats of this Region are experiencing changes similar to those in the Greater North Sea, with knock-on effects in wider food webs.

Bay of Biscay and Iberian Coast

The most important pressures here (Region IV) originate from fishing, shipping, tourism and recreation, land-based industry, and agriculture. Fishing and aquaculture are particularly widespread. For instance, in 2018, mobile bottom trawls were found to have been deployed over almost one fifth of the Region, and Spain and France have well-developed coastal aquaculture. There is no clear trend in nitrate inputs in this Region, by contrast with the decreasing trends in other regions. Important shipping routes exist across the Bay of Biscay and off the Western Iberian Coast.

The QSR 2023 highlights significant impacts on marine ecosystems and biodiversity in parts of this Region. Localised but persistent areas of oxygen deficiency are found in areas of relatively high eutrophication, such as those adjacent to particular catchments in the Bay of Biscay sub-region where excessive nutrient inputs continue to occur. Hazardous substances are also found in these areas, and concentrations are rising in some parts of the Iberian coast. Fishing pressure is high in continental shelf areas, and aquaculture is widely practiced in coastal areas of the Region. Litter is widespread but trends point to slight declines.

Cumulative pressures affect biodiversity in this Region just as in others, although the pressures are concentrated in nearshore areas; large portions of this Region have less human activity than the Greater North Sea and Celtic Seas. The status of assessed commercial and sensitive fish species is ‘not good’ overall, although the proportion of populations in good status is relatively higher than in the other assessed OSPAR Regions. Surface feeding and water column feeding birds are assessed as having ‘not good’ status, as are small toothed cetaceans, for which fisheries by-catch is cause for concern. As in other OSPAR Regions, the status of pelagic habitats is ‘not good’, and this has ramifications for marine food webs in this Region. Physical disturbance of the seabed has also affected benthic habitats in parts of this Region together with negative effects of climate change and ocean acidification.

Wider Atlantic

The only human settlements within the Wider Atlantic (Region V) are in the Azores, so pressures from land-based human activities are generally low. Although fishery catches in this Region are a relatively small proportion of the total, some OSPAR threatened or declining species remain vulnerable to fisheries pressure. There is potential for mining deep seabed minerals, activities which could impact pelagic and benthic habitats and wider food webs. Compared with the other OSPAR Regions the Wider Atlantic is under-assessed, but certain pressures are expected to increase, such as low-frequency noise, litter, and contaminants from shipping.

Due to the vastness and remoteness of this Region, there is also limited understanding of its state of biodiversity. However, OSPAR has identified certain benthic habitats as threatened or declining in the Wider Atlantic, including deep-sea sponge beds, carbonate mounds, coral gardens, Lophelia pertusa reefs, oceanic ridges with hydrothermal vents, and seamounts. The carbonate mounds in this Region are the largest known globally, and since the QSR 2010 new mounds have been discovered on the Iberian margin of the Galicia Bank. Future assessments may well expand the knowledge base of this OSPAR Region.