Welcome to the MedLibrary.org Wikipedia Supplement on Anadromous -- Please Click to Return to Front Page

Many species of Salmon are anadromous and migrate long distances up rivers and streams to spawn.

Many types of fish migrate on a regular basis, on time scales ranging from daily to annual, and over distances ranging from a few meters to thousands of kilometers. Fish usually migrate because of diet or reproductive needs, although in some cases the reason for migration remains unknown.

Classification

• potamodromous fish migrate within fresh water only (Greek: Potamos is river).
• oceanodromous fish migrate within salt water only (Greek: 'Oceanos' is ocean).
• diadromous fish travel between salt and fresh water (Greek: 'Dia' is between).

• anadromous fish live in the ocean mostly, and breed in fresh water (Greek: 'Ana' is up; The noun is "anadromy")
• catadromous fish live in fresh water, and breed in the ocean (Greek: 'Cata' is down)
• amphidromous fish move between fresh and salt water during their life cycle, but not to breed (Greek: 'Amphi' is both)

Examples

Some of the best-known anadromous fish are the five species of Pacific salmon, which are Chinook (King), Coho (Silver), Sockeye (Red), Chum (Dog) and Pink (Humpback). The salmon hatch in small freshwater streams. From there they migrate to the sea to mature, living there for two to six years. When mature, the salmon return to the same streams where they were hatched to spawn. Salmon are capable of going hundreds of kilometers upriver, and humans must install fish ladders in dams to enable the salmon to get past. Other examples of anadromous fishes are sea trout, three-spined stickleback, and shad.

Life cycle of anadromous fish. From a U.S. Federal Government pamphlet. (Click image to enlarge.)

The most remarkable catadromous fishes are freshwater eels of genus Anguilla, whose larvae drift on the open ocean, sometimes for months or years, before travelling thousands of kilometres back to their original streams (see eel life history).

An example of an make an amphidromous species is the Bull shark, which lives in Lake Nicaragua of Central America and the Zambezi River of Africa. Both these habitats are fresh water, yet Bull sharks will also migrate to and from the ocean. Specifically, Lake Nicaragua Bull sharks migrate to the Atlantic Ocean and Zambezi Bull sharks migrate to the Indian Ocean.

Diel vertical migration is a common behavior; many marine species move to the surface at night to feed, then return to the depths during daytime.

A number of large marine fishes, such as the tuna, migrate north and south annually, following temperature variations in the ocean. These are of great importance to fisheries.

Freshwater fish migrations are usually shorter, typically from lake to stream or vice versa, for spawning purposes.

Historic exploitation

Since prehistoric times humans have exploited certain anadromous fishes during their migrations into freshwater streams, when they are more vulnerable to capture. Societies dating to the Millingstone Horizon are known which exploited the anadromous fishery of Morro Creek¹ and other Pacific coast estuaries. In Nevada the Paiute tribe has harvested migrating Lahontan cutthroat trout along the Truckee River since prehistoric times. This fishing practice continues to current times, and the U.S. Environmental Protection Agency‎ has supported research to assure the water quality in the Truckee can support suitable populations of the Lahontan cutthroat trout.

Highly migratory species

See also: Straddling stock

The term highly migratory species (HMS) has its origins in Article 64 of the United Nations Convention on the Law of the Sea. The Convention does not provide an operational definition of the term, but in an annex lists species considered highly migratory by parties to the Convention. These are species which undertake migrations of significant but variable distances across oceans for feeding or reproduction, and also have wide geographic distributions. Thus, these species are found both inside the 200 mile exclusive economic zones and in the high seas outside these zones. The term usually denotes tuna and tuna-like species, shark, marlin and swordfish. They are pelagic species, which means they mostly live in the open ocean and do not live near the sea floor, although they may spend part of their life cycle in nearshore waters.²

See also

• DSSAM Model
• Fish ladder
• Hydrology transport model
• Ocean Tracking Network
• Salinity
• Stenohaline
• Euryhaline
• Lessepsian migration

Notes

References

• Blumm, M (2002) Sacrificing the Salmon: A Legal and Policy History of the Decline of Columbia Basin Salmon Bookworld Publications.
• Bond, C E (1996) Biology of Fishes, 2nd ed. Saunders, pp. 599-605.
• Hogan, C M (2008) Morro Creek, The Megalithic Portal, ed. by A. Burnham

v • d • e Wild fisheries Wild fisheries Ocean fisheries · Forage fisheries · Krill fisheries · Kelp fisheries · Eel fisheries · Shrimp fisheries · Crab fisheries · Ocean habitats · Shoaling · Migration · Sardine run · Fish ladder · Water column · Marine snow · Upwelling · Humboldt current · Red tides · Dead zones · Fish kill Fisheries science Population dynamics of fisheries · Shifting baseline · Biomass · Fisheries acoustics · Fish measurement · Fish counter · Fish stock · Age class structure · Trophic cascades · Marine biology · Aquatic ecosystems · Fish types · Bioeconomics · Fisheries databases · Institutes · Fisheries scientists Management Fisheries management · Monitoring control and surveillance · Vessel monitoring system · Fishery Resources Monitoring System · Catch reporting · Fisheries observer · Illegal, unreported and unregulated fishing · Fisheries organizations Quotas Individual fishing quota · Minimum landing size · Incidental mortality · Discards · Bycatch · Cetacean bycatch  · Turtle excluder device  · EU quotas · EU MLS · Exclusive Economic Zone Sustainability Overfishing · Marine pollution · Environmental effects of fishing · Sustainable yield in fisheries · Marine Protected Area · Marine reserve · Marine conservation · Marine conservation activism · Sustainable seafood · Marine Stewardship Council · Friend of the Sea · Seafood Watch

v • d • e Fisheries and fishing topic areas Fisheries Fisheries science · Wild fisheries · Ocean habitats · Fish farming · Aquaculture · Fish types · Fisheries management · Fishing quota · Sustainablity Fishing Fisherman · Artisan fishing · Fishing vessels · Fishing history Industry Commercial fishing · Processing · Products · Marketing · Markets Recreational Angling · Game fishing · Fly fishing · Catch and release · Regional fishing · Angling personalities Techniques Gathering · Spearfishing · Line fishing · Netting · Trawling · Trapping · Other Tackle Hook · Line · Sinker · Rod · Bait · Lures · Artificial flies · Bite alarms Locations Fishing by country · Regional · Fishing villages · Fishing banks List of articles by topic areas · Alphabetical list of articles · Fisheries glossary

Wikipedia content modification information:

• This page was last modified on 2 January 2009, at 15:40.

Wikipedia Authorship and Review

Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.

Wikipedia Usage Guidelines

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Anadromous".

The URL for this specific entry is:

• http://medlibrary.org/medwiki/Anadromous

All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.