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anadromous

American  
[uh-nad-ruh-muhs] / əˈnæd rə məs /

adjective

  1. (of fish) migrating from salt water to spawn in fresh water, as salmon of the genera Salmo and Oncorhynchus (distinguished from catadromous).


anadromous British  
/ əˈnædrəməs /

adjective

  1. (of fishes such as the salmon) migrating up rivers from the sea in order to breed Compare catadromous

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

anadromous Scientific  
/ ə-năd′rə-məs /
  1. Relating to fish, such as salmon or shad, that migrate up rivers from the sea to breed in fresh water.


Etymology

Origin of anadromous

First recorded in 1745–55, anadromous is from the Greek word anádromos running upward. See ana-, -drome, -ous


Explanation

Anadromous is used to describe animals, usually fish, that live in the ocean but travel back up through rivers so they can breed in fresh water. The word anadromous comes from Greek, and means "running upward." When fish swim from the oceans up to the rivers, it's called a run. The most famous version of this is a salmon run, where salmon, an anadromous species, swim all the way from the ocean up to the creek they hatched in. They lay eggs there so that a new generation of salmon will hatch and complete the cycle all over again.

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

In the Arctic Yukon, however, the cats occupied a very different ecological role as tertiary consumers and likely specialized in anadromous fish such as salmon.

From Science Daily ● Sep. 8, 2026

Salmon are anadromous, meaning they spend much of their lives in the ocean but return to freshwater rivers to spawn.

From BBC ● Apr. 3, 2024

Dams do not allow for a free-flowing river, Kurt Tardy, anadromous fisheries biologist for the Shoshone-Bannock Tribes, told the Statesman.

From Seattle Times ● Aug. 15, 2022

Among the regulations the commissioner would adopt is what defines an anadromous fish habitat.

From Washington Times ● Oct. 2, 2018

The migratory fishes fall into two groups, the anadromous and the catadtomous.

From Boy Scouts Handbook The First Edition, 1911 by Boy Scouts of America

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