A class of movement which forces the fishes to return back in that place from where they have been migrated is called fish migration. The majority of fishes are restricted with small territorial limits. So, they do not go out from their home ranges. However, some fishes show seasonal migration in search of food, shelter, and better breeding place.
They are true migratory fishes which migrate in between the sea and fresh water. They are divided into three subtypes. They are:
They spent the major part of their life in sea water but migrate towards the fresh water for breeding. After laying eggs, they return back to sea water again. Eg; Salmon, Milsa, Lamprey etc.
They spend the major part of their life in freshwater but migrate towards sea water for breeding. After laying eggs they return back to fresh water again. Eg; European eel, American eel, Bam eel etc.
They migrate from seawater to freshwater to seawater at any time for any reason but not for breeding purpose. Eg; Gobies fishes.
Their migration is confined within freshwater only. Eg; Carpitrout etc.
There is confined within seawater only. Eg; Clupea, Scomber, Thunnus etc.
(a) Alimental or feeding migration: It is the migration with reference to the search of suitable food materials during winter and spawning site.
Fishes migrate towards north during spring and towards south during autumn. Eg; swordfish.
Fishes show up and down migration in the water body to search food, better climatic condition and to escape from predators. Eg; Mackerel migrate towards the surface of the water to feed planktons.
Migration from feeding to breeding place. Eg: Hilsa
Migration from breeding to feeding place. Eg: Eel.
Overwintering is the inactive stage of life cycle of fishes in which they stop feeding less consumption of oxygen, low activities etc to search the proper place for that period they migrate. Eg; flatfishes.
Temporary movement of fishes on land. Eg; common eel can travel in moist land found in between two ponds.