EVERYDAY SCIENCE

Detailed explanation-1: -Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres.

Detailed explanation-2: -Introduction to Fish Migration Fish need to move! They need to find food, find places to spawn, to hide or rest-and they need aquatic connections between all of these places.

Detailed explanation-3: -(a) Anadromous migration: When fresh water fish exhibit migration from spawning areas (fresh water) to feeding areas (ocean). e.g. Brown trout, Petromyzon, Gasterosteus etc.

Detailed explanation-4: -Anadromous fish spend most of their adult lives at sea, but must return to freshwater to spawn. Catadromous fish live most of their adult lives in freshwater, but must return to saltwater to spawn. Collectively these two groups are sometimes referred to as diadromous.

Detailed explanation-5: -During their life cycle, anadromous long distance migratory fish (spawning in fresh water) and the catadromous eel (spawning in sea water) migrate from the sea into fresh water or from fresh water into the sea. Salmon spend their main growth period in the sea, but return to the rivers for spawning.