Atlantic salmon

Atlantic salmon (Salmo salar, from the Latin words "Salmo" meaning salmon, and "salar" meaning "leaper") is a fish species of the Salmonidae family found in the northern Atlantic Ocean and in rivers that flow into the Atlantic.

The Atlantic salmon follows an "anadromous" fish migration pattern, in that it undergoes its greatest feeding and growth in salt water; but adults return to spawn in native fresh water streams where the eggs hatch and juveniles grow through several distinct stages. Atlantic salmon normally return to the precise fresh water tributary in which they were born, and it is believed that odour - the exact chemical signature of that stream - plays an important role in this process.

The fresh water stage of Atlantic salmon growth - normally 2 to 4 years, but ranges from 1 to 6 - is longer than the salt water stage. In fresh water the salmon feed on insects, crustaceans, some mollusks and other fish. Most of the rapid growth of the Atlantic salmon, however, occurs in the 1 to 4 year salt water phase of its life cycle where it will consume squids, shrimp and other fish. Typically, the Atlantic salmon migrates in schools from its home stream to an area on the continental plate off West Greenland, before returning to its natal river to spawn. After returning to its natal stream the salmon will cease eating altogether prior to spawning.

Atlantic salmon do not require salt water, however, and numerous examples of fully fresh water ("landlocked") populations of the species exist throughout the Northern Hemisphere. In North America, the landlocked strains are frequently known as ouananiche.

Unlike the various Pacific salmon species, the Atlantic salmon does not automatically die after spawning, and may recondition themselves, return to the sea to repeat the migration and spawning pattern multiple times. Nevertheless migration and spawning exact an enormous physiological toll on the individual fish, such that repeat spawners are the exception rather than the norm.

Atlantic salmon breed in the rivers of Western Europe from Northern Portugal north to Arctic Norway, Iceland, Greenland, and the east coast of North America from Connecticut in the United States north to Northern Labrador in Arctic Canada. At sea, it is found mainly in the waters off Greenland and in migrations to and from its natal streams.

Escape from commercial salmon farms in the northern Pacific have introduced the Atlantic salmon into the range of the Pacific species. Extensive efforts are underway to prevent escapes and the spread of Atlantic salmon in the Pacific and elsewhere. In the United States and elsewhere efforts to restore salmon to their native habitats are underway and there is some slow but steady progress. Restoration and protection of the habitat itself is key to this process. In the Great Lakes, Atlantic Salmon have been introduced successfully, but the actual percentage of Salmon reproducing naturally is very low. Most are stocked annually. Atlantic salmon were native to Lake Ontario but were extirpated by habitat loss and overfishing in the late 1800s. The state of New York has since been annually stocking its adjoining rivers and tributaries with the fish and in many cases do not allow active pursuit of the species.

In New England, many efforts are underway to restore salmon to the region by knocking down obsolete dams and updating others with fish ladders and other contraptions that have proven effective in the West with Pacific salmon. There is some success thus far, with populations growing in the Penobscot River and the Connecticut River.

As in other cold water fish species, Atlantic salmon have a high oil content in their flesh. These oils, in particular Omega-3 and Omege-6 fatty acids are known to have substantial positive health benefits for humans.

Currently, overfishing, habitat loss and artificial propagation are the greatest threats to natural Atlantic Salmon populations.

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Salmonidae | Arctic freshwater fish | New Zealand introduced freshwater fish

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