Effects on marine and human life

The marine organisms of the Gulf Stream system are not of great commercial value. Principal species include the bluefin tuna, the Atlantic salmon, and the flying fish. Its warm waters, however, in mingling with the colder waters both on the Grand Banks and off northwestern Europe, contribute to turbulence and the availability of nutrient salts that made these regions among the most productive commercial fishing grounds in the world until they were overfished in the 1980s and early ’90s.

A major contribution of the Gulf Stream system is its warming effect upon the climates of adjacent land areas. In winter the air over the ocean west of Norway is more than 40 °F (22 °C) warmer than the average for that latitude, one of the greatest temperature anomalies in the world. The prevailing westerly winds carry the warmth and moisture of the ocean to northwestern Europe, giving Bergen, Norway, at 60° N latitude, an average high temperature for its coldest month of 34 °F (1 °C), while Reykjavík, Iceland, 4° of latitude farther north, has a 31 °F (0 °C) average for its coldest month. In southwestern England the climatic modification produced by the current is reflected in the extraordinary mildness of the winters at this northern latitude, including the growing of winter vegetables and flowers and the presence of subtropical vegetation and lemon trees in southern Devonshire. Along the western margins of the North Atlantic, however, where the winds are predominantly from the shore, the Gulf Stream has little effect. Halifax, Nova Scotia, Canada, nearly 1,000 miles south of Bergen, averages only 23 °F (−5 °C) during its coldest month.