Sunlight entering the water may travel about 1,000 meters (3,280 feet) into the ocean under the right conditions, but rarely the light reach beyond 200 meters (656 feet). The ocean is divided into three zones based on depth and light level. The upper 200 meters (656 feet) of the ocean is called as the euphotic, or "sunlight," zone. This zone contains the vast majority of commercial fisheries and is home to many protected marine mammals and sea turtles. Only a small amount of light penetrates beyond this depth because the light intensity dissipates as depth increases.