World Fish Migration Day
World Fish Migration Day is held on April 21. This event in the third decade of the month April is annual. 
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On April 21 is World Fish Migration Day — a day to create awareness about the importance of open rivers and migratory fish.
To scale through rapids, river herring don’t jump over them like salmon. They swim very fast and in short bursts.
Sea-run fish are also referred to as diadromous, meaning that they spend part of their life in freshwater and another part in saltwater. Diadromous fish are either: Anadromous, spending most of their adult life at sea, but returning to freshwater to spawn, or Catadromous, spending most of their adult life in freshwater, but returning to the sea to spawn.
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