Migration in Fishes
Many fishes migrate on regular basis, on a time scale ranging from daily to annually or longer. It may be of short distance over a few meters to thousands of kilometers.
Reason for Migration in Fishes: Fishes usually migrate to feed, to reproduce, or in some cases the reason is not known.
Classification of Migration:
- Anadromous
- Catadromous
- Oceanodromuos
- Diadromous
- Amphidromous
- Potamodromous
Anadromous:
Anadromous fishes migrate from the sea up into freshwater to spawn, examples – salmon, striped bass
- These fishes spend most of their lives living and feeding in the sea.
- Salmon and striped bass are well-known Anadromous fishes, that make large migrations. Salmon spawn in the cold, clear waters of lakes or upper streams. They lay eggs in gravel beds.
- Salmon stops feeding during the journey and changes its body colour from silver to reddish-brown.
Catadromous:
Catadromous fishes migrate from fresh water down into the sea to spawn. Freshwater Eels (A. anguilla) are catadromous fishes. They spend most of their lives in freshwater.
- During the journey, the eel changes colour of the body from yellow to metallic silver grey.
Oceanodromous:
fish that live and migrate wholly in the sea. These occur widely throughout the world’s ocean. Example- Herring (Clupea harengus), Cod (Gadus morhua), Tuna
Diadromous:
George S. Myers coined the inclusive term diadromous to refer to all fish that migrate between the sea and freshwater
Amphidromous:
fish that migrate from freshwater to the seas, or vice versa, but not for the purpose of breeding
potamodromous:
fish whose migrations occur wholly within freshwater. Example- Carps, Catfish
Some other movements also fund in fishes like-
- George S. Myers coined the inclusive term diadromous to refer to all fish that migrate between the sea and freshwater
- Some fish such as tuna move to the north and south at different times of year following temperature gradients.
- Altitudinal migration
- The bull shark is aneuryhaline species that move at will from fresh to salt water, and many marine fish make a diel vertical migration, rising to the surface to feed at night and sinking to lower layers of the ocean by day.
- Freshwater movement of fishes also occurs, often the fish swim upriver to spawn.

Migration in fishes
Significance of Migration in Fishes:
- For suitable feeding and spawning places
- For protection from predators
- For increasing genetic diversity
- An adaptation in character to survive from extreme climatic conditions.
You can also read:
- Scoliodon – Dogfish, Classification, and Characteristics
- Characteristics and Classification of Phylum- Chordata
- Subphylum – Urochordata
- Herdmania- Sea Squirts
- Amphioxus (Lancelet)
References: Kotpal Vertebrata (Book for graduation)
https://en.wikipedia.org/wiki/Fish_migration
Thank You 🙂
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