Grand Banks, shallow fishing region of the North Atlantic Ocean, lying off southeastern coast of the island of Newfoundland, Canada. The region consists of several banks, the largest being Grand Bank, that rise from the continental shelf. It extends for 560 km (350 mi), and its depths generally range from 40 to 180 m (120 to 600 ft). The cold Labrador Current crosses most of the banks, and the warm Gulf Stream flows along the eastern part of the region. The mingling of the two currents, plus the shallowness of the water, provide a favorable environment for plankton, on which fish depend for food. As a result, the Grand Banks is one of the world's leading fishing grounds, especially for cod, haddock, herring, and mackerel. Heavy fog often shrouds the region.