How Scientists Reveal The Secret Migrations of Fish

Abstract

Animal migration is the seasonal movement from one region to another and can involve thousands of individuals journeying across continents and oceans. Scientists often use electronic and physical tags to track the movements of migratory fish. However, these tags only work on bigger fish and only give a limited picture of where the fish have been. However, scientists discovered how to use fish otoliths (“ear stones”) to reveal the secret journey of migrating fish over their entire lifetime. Otoliths grow a new layer every day of the fish’s life, producing growth bands just like a tree. The otoliths incorporate chemical elements from the water as the fish grow and move, providing a chemical map of where the fish have been. The growth bands also tell us how long the fish spent in each habitat and how fast they grew. This information helps conservationists understand which habitats are most important and how to protect endangered species. In this paper, we are going to take you on a journey into the wonderful world of fish migration and introduce you to a tiny ear stone that eavesdrops on the lives of fish, recording their every movement and so much more...