Editing Fish migration (section)

{{short description|Movement of fishes from one part of a water body to another on a regular basis}}
{{Redirect-distinguish|Anadromy|Anadrome}}
[[File:Jumping Salmon.jpg|thumb|right|upright 1.3 |Many species of [[salmon]] are anadromous and can migrate long distances up rivers to [[Spawn (biology)|spawn]]]]
[[File:Fish Migration.webm|thumb|290px|Allowing fish and other migratory animals to travel the rivers can help maintain healthy fish populations]]

'''Fish migration''' is [[animal migration|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.<ref>{{Cite journal |last=McDermott |first=Amy |date=2025-05-21 |title=Where do fish go and why? For many species, nobody knows |url=https://www.wikidata.org/wiki/Q134591927 |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=122 |issue=21 |doi=10.1073/PNAS.2510827122}}</ref>

Fish migrations involve movements of [[school of fish|schools of fish]] on a scale and duration larger than those arising during normal daily activities.<ref>Dingle, Hugh and Drake, V. Alistair (2007)  "What Is Migration?". ''BioScience'', '''57'''(2):113–121. {{doi|10.1641/B570206}}</ref> Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to [[spawn (biology)|spawn]]; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn.<ref>{{Cite journal|last1=Gross|first1=Mart R.|last2=Coleman|first2=Ronald M.|last3=McDowall|first3=Robert M.|date=1988-03-11|title=Aquatic Productivity and the Evolution of Diadromous Fish Migration|url=https://www.science.org/lookup/doi/10.1126/science.239.4845.1291|journal=Science|volume=239|issue=4845|pages=1291–1293|doi=10.1126/science.239.4845.1291|pmid=17833216 |bibcode=1988Sci...239.1291G |s2cid=241447 |url-access=subscription}}</ref>

Marine [[forage fish]] often make large migrations between their spawning, feeding and nursery grounds. Their movements are associated with ocean currents and with the availability of food in different areas at different times of the year. The migratory movements may partly be linked to the fact that the fish cannot identify their own offspring and moving in this way prevents [[cannibalism]]. Some species have been described by the [[United Nations Convention on the Law of the Sea]] as highly migratory species. These are large [[pelagic fish]] that move in and out of the [[exclusive economic zones]] of different nations, and these are covered differently in the treaty from other fish.

[[Salmon]] and [[striped bass]] are well-known anadromous fish, and freshwater [[eel]]s are catadromous fish that make large migrations. The [[bull shark]] is a [[euryhaline]] species that moves 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. Some fish such as [[tuna]] move to the north and south at different times of year following temperature gradients. The patterns of migration are of great interest to the fishing industry. Movements of fish in fresh water also occur; often the fish swim upriver to spawn, and these traditional movements are increasingly being disrupted by the building of dams.<ref name=Woo2019 />