The Gulf Stream forms water rings, or eddies, that can influence the productivity of fishing areas. Eddies are sections of moving water that swirl off from the main Gulf Stream current and loop back on themselves, forming something like whirlpools. These eddies consist of water that is of different temperature than the water that surrounds them. On the surface, eddies are usually about 100–300 km in diameter. However, they are not just surface features. They are cylinders of water that can reach to depths of almost 4000 m. The SST image below shows three well-developed eddies, revealed by the difference in sea surface temperatures.

  !   Examine the SST image to identify the eddies. Move your cursor over the image to show a diagram of water temperature and motion. Click the red dots to see animations showing how warm and cold eddies form.