Few of the world’s seas have come under such environmental pressure as the Baltic and North seas. Both seas are surrounded by cities, ports, and industry and some of the most intensively farmed land in the world. The North Sea has long been important as one of Europe’s most productive fisheries. It also serves as a prominent shipping zone among European countries and between Europe and the Middle East.
The North Sea (historically also known as the German Ocean) is a part of the Atlantic Ocean, located between Norway and Denmark in the east, Scotland and England in the west, and Germany, the Netherlands, Belgium and France in the south. The North Sea is bounded by the coastlines of England, Scotland, Norway, Sweden, Denmark, Germany, the Netherlands, Belgium and France, and by imaginary lines delimiting the western approaches to the Channel (5°W), the northern Atlantic between Scotland and Norway (62°N, 5°W), and the Baltic in the Danish Straits.
The Norwegian and British sectors hold most of the large oil reserves. It is estimated that the Norwegian sector alone contains 54% of the sea’s oil reserves and 45% of its gas reserves. More than half of the North Sea oil reserves have been extracted, according to official sources in both Norway and the UK. The North Sea is a shared body of water between the United Kingdom (UK), Norway, Netherlands, Belgium, Denmark, France, and Germany. It’s also home to 184 offshore oil rigs, making it one of the largest offshore drilling areas in the world.
The North Sea is partially sheltered by the United Kingdom. Here, wave researchers believe that the significant wave height could be 14-15 metres. Single waves in the North Sea can consequently be twice this height.
Lost at the bottom of the North Sea almost eight millennia ago, a vast land area between England and southern Scandinavia which was home to thousands of stone age settlers is about to be rediscovered.
The North Sea has some large islands that are home to thousands of people. However, some of the islands are protected areas because of their importance in preserving marine life. The Shetland Islands have a total population of about 23,000 people, while some 22,000 people live on the Orkney Islands.
They are conduits for shipping, places for recreation, drains for sewage, dumps for waste and toxic chemicals, and sources of fish for food on an immense scale. And the North Sea, too, is, of course, a major oil and gas field. It is in some ways surprising that the environmental situation is not worse than it is – but it is certainly bad.
The schools of herring
One of the key issues in the North Sea is fishing. In the past, the North Sea was a fantastically rich source of fish. Fish such as cod, haddock, whiting, plaice, sole, mackerel, herrings, sprats, sturgeons, shads, rays, and skates, and shellfish such as oysters, mussels, and whelks, were once so abundant that the North Sea supported the world’s richest fishing industry. For centuries, the fishing villages that lined the North Sea coast, from Lowestoft and Hull on the British side to Ålesund on the Norwegian side, were boom towns, and fishermen’s tales of huge hauls were the stuff of legend and song. Even today, this little sea supplies 5 percent of all the world’s fish. But the catch today is far below what it was a century ago.
Sturgeon, shad, rays, skates, and mackerel have seen especially dramatic declines, but so have all fish species. Oysters vanished as long ago as the 1930s – they were victims of steam trawlers, which dragged their heavy nets over the rich mosaic of invertebrate life on the North Sea floor, destroying oysters, corals, and seafan beds alike. It is estimated that 99 percent of fish mass has now been removed from the North Sea. All fish catches have declined dramatically since the 1970s, with the haddock catch plummeting from 1 million tonnes (1.1 million tons) in 1970 to fewer than 100,000 tonnes (110,000 tons) now.
Quota battles
The North Sea is now the focus of a constant battle between the fishing industry, regulatory authorities, and scientists, as they try to balance the conflicting demands of business, livelihoods, politics, and marine life. On the whole, it has been marine life that has been the loser, despite the European Union’s Common Fisheries Policy and the imposition of quotas limiting the catch of most commercial fish. Mackerel fishing was banned completely in the 1970s, and herring, cod, and plaice fishing may soon be banned completely, too. But many experts fear that it may be too late.
The numbers of cod are now so low that there have been calls every year since 2001 for a total ban on cod fishing in the North Sea. Yet although quotas have been steadily reduced, cod can still be legally caught – it seems that the lessons of Newfoundland’s Grand Banks (see pages 156–157) have not been learned. In the horse-trading of quotas, any faint signs of stock improvement in some species, such as herring, are traded off with raised quotas to smooth over the quota reductions in other species. Of course, the quotas are bitterly contested by fishing crews who see their livelihood vanishing, and many North Sea fishing villages now face a bleak future.
Cod gone
Some experts believe that cod and other fish will soon disappear from the North Sea altogether because overfishing is combined with another threat – global warming. The North Sea has warmed by more than 1°C (1.8°F) over the last 40 years. It does not sound much, but it has been enough to reduce numbers of the tiny shrimplike copepod by more than 60 percent. In spring, young cod rely on a tiny species of copepod for their food, and without copepods the cod simply cannot grow to maturity. And in a classic example of the effects on one species reverberating through the ecosystem, a reduction in adult cod has led to a proliferation of the seafloor crabs and shrimp on which they feed. Crab larvae are voracious predators and as their numbers exploded, they have been decimating the North Sea’s bivalves and the young of cod, plaice, and sole. The consolation is that what may be the North Sea’s loss could be the gain of cooler seas farther north, such as the Barents, as copepod and cod find them more to their liking.