Answer:
Fish migration to other parts of the ocean results when there is a lack of upwelling during an El Nino period.
Step-by-step explanation:
During an El Nino period, the trade winds blow towards the east and keep eastern Pacific Ocean warmer.
Ocean upwelling due to trade wind brings nutrient-rich cool and dense water to the ocean’s surface. Upwelling makes the surface ocean water fertile for a healthy marine life.
El Nino not only affects the ocean’s surface water temperature but also the strength and speed of the ocean currents, all of which affects marine life.
During El Nino Southern Oscillation when there is a warm phase, the trade wind becomes weak and warm water is pushed into the eastern Pacific Ocean.
Due to weaker trade winds, upwelling of ocean waters is reduced and the nutrient-rich waters remain in the deep and far from the coastal areas.
This makes the fishes like anchovies to migrate from the surface waters to deep and far ocean areas in search of nutrients.