El nino is a climate cycle where the temperature of the Pacific Ocean changes because of movements of air and ocean currents. During this period, the trade winds in the south weaken, causing the warm water to move from the Western region to the Eastern region.
Step-by-step explanation:
El nino is the resultant climatic pattern occurring due to changes in the global weather pattern and the trade winds near the equatorial regions.
In the equatorial regions, the weakening trade winds increase the temperature of the surface waters of the western Pacific Ocean and alter the atmospheric pressure which pushes the warm surface waters from western Pacific Ocean to the eastern regions. This also changes the upwelling pattern of the ocean leading to migration of marine organisms.
El Nino brings huge rainfall to regions along the South American coast but drought around Indonesia and Australia. El nino occurring in central equatorial regions brings in global changes in weather conditions like storms in one region and drought in another region as well as migration of fish population from one region to another.