Definition of "anadromous"

Alewives are anadromous fish: Born in freshwater, they spend their lives in the ocean, returning annually to their birthplaces to spawn.

2014 April 20, Richard Conniff, “An evolutionary family drama”, in The New York Times‎

Bird migration routes favor marshes and river valleys, as do, more obviously, the movement of anadromous salmon and, the mirror image, catadromous eels, to mention only two of the numerous migrating fish species.

2017, James C Scott, chapter 1, in Against the Grain, New Haven & London: Yale, page 53

Emphasizing that it has applied equitable apportionment to not only rivers and streams but also to interstate river basins, to groundwater pumping that affects surface water flows, and to anadromous fish like Chinook salmon and steelhead trout, the court stated that equitable apportionment applies only when transboundary resources are at issue.

2021 November 23, Robin Craig, “In dispute over groundwater, court tells Mississippi it’s equitable apportionment or nothing”, in SCOTUSblog