This current drives the surface water away from the equator, and draws water up from below.
Winds also cause warm surface water to accumulate on the western side of the Pacific.
As a result, nutrient-rich water rises from deeper levels to replace the surface water that has drifted away. These nutrients are responsible for supporting the large fish population commonly found in these areas. Fish then die off or move elsewhere, such as southward off Chile or north toward California. One of the main areas of the globe most seriously affected is Australia. The fluctuations of climate and other environmental effects also operate on a large scale.