The overviews describe the current states of the respective ecosystems, the main human pressures on them, and how these pressures impact ecosystem components. Synthesizing available information on the two ecoregions, the documents also highlight the capacity of ICES to meet the needs of integrated knowledge on status of the marine ecosystem. The two overviews are the latest additions to a collection which already includes the Barents Sea, Bay of Biscay and Iberian Coast, Celtic Seas, and Greater North Sea – all of which were published last year.
The Icelandic Waters ecoregion surrounds Iceland. Here, colder and fresher waters from the Arctic and warmer saltier water from further south in the Atlantic mix, generating a productive ecosystem supporting large fish stocks and rich fisheries along with large populations of marine birds and mammals. The warming of the oceans caused by the increased dominance of southern waters has meant that a number of previously rarer fish species have become more abundant in recent years. Stocks of the northern cold water shrimp, however, have collapsed due to increased predation by gadoids such as cod, high fishing mortality, and increasing water temperatures. A decline in seabird and some whale populations has been linked to a decline in sandeel.
In this region the main human pressure comes in the form of fisheries, but this activity has been well managed, leading to fish stocks that are currently healthy. Seabed abrasion and bycatch of non-target species are examples of the side effects of fishing.
The Norwegian Sea ecoregion lies to the north of Icelandic waters and to the west of central Norway. Its waters include the remote island of Jan Mayen, stretching far to the north and taking in sections of deep ocean basins. The main activity in the region is fishing on the large stocks of herring and blue whiting. Over recent years, the northeast Atlantic mackerel stock has spread into the area.
Other human activities in the ecoregion include the extraction of oil and gas and shipping – the latter occurring mostly relatively close to the coast of mainland Norway. Oceanographic change has probably been the cause of a decrease in zooplankton abundance. The herring stock has also declined and numbers of seabirds have decreased steeply over the last decade, probably due to the decline in small herring, one of their main foods.
Photo: Svanhildur Egilsdóttir, Marine Research Institute (HAFRO), Iceland