World Fish Migration Day – 21st May
World Fish Migration Day – 21st May
World Fish Migration Day is a one-day global celebration take place every alternate year to raise awareness for the importance of free-flowing rivers and migratory fish.Every year, millions of fish: salmon, steelhead trout, shad, alewives, and sturgeon, etc., migrate to their native habitats to reproduce. Some fish need to swim thousands of miles through oceans and rivers to reach their destination.
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. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear.Types of migration are categorized as follows *anadromous, in which adult fish live in the sea and migrate into fresh water to spawn, example: Salmon ( Salmo Sps.) * catadromous, in which adult fish live in fresh water and migrate into salt water to spawn, example: Eels ( Anguillasps.) * Diadromous: all fish that migrate between the sea and fresh water. * Amphidromous: fish is a type of diadromous fish, that migrate from fresh water to the seas, or vice versa, but not for the purpose of breeding.example: Hawaiian Goby (Awaous sps.) * Potamodromous: fish whose migrations occur wholly within fresh water, example: endangered Colarado Pikeminnow(Ptychocheilus lucius). * Oceanodromous: fish that live and migrate wholly in the sea, example: Hering ( Lupen Havengus).
Migrating fish are under threat by habitat modification, fragmentation and destruction of spawning and nursery habitats, pollution, and overexploitation.Damming is a major threat to migratory fish.
– Source: Internet –