. El Niño affects the distribution in fish. During El Niño, physical and biological changes occur in oceans. These changes are of temperatures in the Pacific ocean. A normal cycle pushes warm water to the western side of the ocean (near Asia and Australia) and colder water is then pushed in the east (near Ecuador, Peru and Chile). However, during El Niño, the wind gets weak and so the warm water in the west goes back to the east. As a result, the eastern Pacific ocean gets warm. So basically El Niño causes warmer water which leads to less phytoplankton. Because there is less Phytoplankton—the bases of the food wed—marine species are highly affected. Eventually, these marine species dramatically decrease in their habitat.