Atlantic salmon 1202747 226112358 2008-07-16T21:39:28Z Chmee2 1153464 + [[cs:Losos obecný]] {{Taxobox | name = Atlantic salmon | status = LR/lc | status_system = IUCN2.3 | image = Salmo_salar.jpg | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Actinopterygii]] | ordo = [[Salmonidae|Salmoniformes]] | familia = [[Salmonidae]] | genus = ''[[Salmo]]'' | species = '''''S. salar''''' | binomial = ''Salmo salar'' | binomial_authority = [[Carolus Linnaeus|Linnaeus]], 1758 }} '''Atlantic salmon''', known scientifically as '''''Salmo salar''''', is a species of [[fish]] in the family [[Salmonidae]], which is found in the northern [[Atlantic Ocean]] and in rivers that flow into the Atlantic and the Pacific.<ref name="Shearer">{{cite book |author=Shearer, W |title=The Atlantic Salmon |publisher=Halstead Press |year=1992}}</ref><ref name="Audubon">{{cite book |title=The Audubon Society Field Guide to North American Fishes, Whales & Dolphins |publisher=Chanticleer Press |year=1983 |pages=395}}</ref> ==Life stages== Most Atlantic salmon follow an [[fish migration|anadromous fish migration]] pattern,<ref name="Audubon"/> in that they undergo their greatest feeding and growth in salt water, but adults return to [[spawn (biology)|spawn]] in native [[fresh water|freshwater]] streams where the eggs hatch and juveniles grow through several distinct stages. Atlantic salmon do not require salt water, however, and numerous examples of fully freshwater ("landlocked") populations of the species exist throughout the [[Northern Hemisphere]].<ref name="Audubon"/> In [[North America]], the landlocked strains are frequently known as ''ouananiche''. ===Freshwater phase=== [[Image:Salmonlarvakils.jpg|thumb|A newly hatched Atlantic salmon alevin which, in around 24 hours, will absorb the [[yolk]] sack and become a fry]] The freshwater phases of Atlantic salmon vary between 1 to 5 years, according to river location. While the young in southern rivers, such as those to the [[English Channel]], are only one year old when they leave, those further north such as in [[Scotland|Scottish]] rivers can be over four years old. The average age correlates to temperature exceeding 7[[Celsius|°C]].<ref name="Shearer"/> The first phase is the [[alevin]] stage. During this phase, the fish stays in the breeding ground and uses the remaining nutrients in their [[egg yolk|yolk]] sack. During this developmental stage, the young gills develop and they become active hunters. Once they are able to do so, they reach the [[spawn (biology)|fry]] stage. The fish grows and subsequently leaves the breeding ground in search of food. During this time, they move to areas with areas of higher prey concentration. The final freshwater stage is when they develop into [[parr (fish)|parr]] in which they prepare for the trek to the Atlantic Ocean. During these times, the Atlantic salmon are very susceptible to [[predation]]. Nearly 40% are eaten by [[trout]] alone. Other predators include other fish and [[bird]]s. ===Saltwater phases=== When parr develop into [[smolt]], they begin the trip to the ocean, which predominantly happens between March and June. Migration usually [[acclimate|acclimatise]] to the changing [[salinity]]. Once ready, young smolt leave, preferring an [[ebb tide]]. Having left their natal streams, they experience a period of rapid growth during the 1 to 4 years they live in the ocean. Typically, Atlantic salmon migrates from its home stream to an area on the continental plate off West [[Greenland]]. During this time in the salmon's life, they face predation from humans, [[Greenland shark]]s, [[skate]], [[cod]], and [[halibut]]. Some [[dolphin]]s have been noticed playing with dead salmon, but it is still unclear whether they consume them. Once large enough, Atlantic salmon change into the [[grilse]] phase where they become ready to return to precise fresh water tributary in which they were born. After returning to its natal stream the salmon will cease eating altogether prior to spawning. Although it is largely unknown how they return to the same spot, it has been suggested that odour — the exact chemical signature of that stream — plays an important rôle in this process. Once above around 250&nbsp;[[gram|g]], the fish no longer become prey for birds and many fish, although [[pinniped|seals]] do prey upon them. Seals that commonly eat Atlantic salmon are the [[Grey Seal]] and [[Common Seal]]. Survivability to this stage has been estimated at between 14 and 53%.<ref name="Shearer"/> ==Nomenclature== The Atlantic salmon was given its scientific binomial name by [[zoology|zoologist]] and [[taxonomy|taxonomist]] [[Carolus Linnaeus]] in 1758. It was not until later, however, that the differently coloured smolts were found to be the same species. The name, ''Salmo salar'', is from the [[Latin]] "''Salmo''", meaning [[salmon]], and "''salar''", meaning "[[leap]]er," according to M. Barton<ref>Barton, M: "Biology of Fishes.", pages 198-202 Thompson Brooks/Cole 2007</ref>, but more likely meaning "resident of salt water." ==Physiology== [[Image:Salmo salar-Atlantic Salmon-Atlanterhavsparken Norway.JPG|thumb|250px|An adult Atlantic salmon displaying its black spotting and blue colouration]] The colouration of young Atlantic salmon does not resemble their adult stage. While they live in freshwater they have blue and red spots. While they mature they take on a silver blue sheen. When they are adults the easiest way of identifying them is by the black spots predominantly above the [[lateral line]], although its [[caudal fin]] is usually unspotted. When they reproduce males take on a slight green or red colouration. The salmon has a [[fusiform]] body, and well developed [[tooth|teeth]]. All fins, save for the adipose, are bordered with black. ==Distribution and habitat== Around the North Atlantic, 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 but issues of excessive harvest and competition with farmed and escaped salmon are also primary considerations. 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 19th century. 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.<ref name="Audubon"/><ref name="Mills">{{cite book |author=Mills, D |title=Ecology and Management of Atlantic Salmon |publisher=[[Springer-Verlag]] |year=1989}}</ref>. Wild salmon on entering rivers as adults [http://ie.youtube.com/watch?v=RxE4fEpzqgY]have characteristically pointed fins which help scientists distinguish from farmed or escaped salmon. ==Diet== After hatching, young salmon begin a feeding response within a couple days. After the yolk sac is absorbed by the body, they begin to hunt. Juveniles start with tiny invertebrates, but as they mature they may occasionally eat small fishes. During this time they hunt both in the [[substrate (marine biology)|substrate]], and also those in the current. Some have been known to also eat salmon eggs. The most commonly eaten foods include [[caddisfly|caddisflies]], [[black fly|blackflies]], [[mayfly|mayflies]], and [[stonefly|stoneflies]].<ref name="Shearer"/> In adulthood, fish feed on much larger food: [[Arctic squid]], [[sand eel]]s, [[amphipod]]s, [[Arctic shrimp]], and sometimes [[herring]]. During this feeding time the fish's size increases dramatically.<ref name="Shearer"/> ==Behavior== Fry and parr have been said to be territorial, but evidence showing that they guard territories is inconclusive. While they may occasionally be aggressive towards each other, the [[sociobiology|social hierarchy]] is still unclear. Many have been found to [[swarm|school]], especially when leaving the estuary. Adult Atlantic salmon are considered much more aggressive than other salmon and are more likely to attack other fish than others. Where they have become an [[invasive species|invasive]] threat it has become a concern that they are attacking native salmon such as [[Chinook salmon]] and [[Coho salmon]].<ref name="Shearer"/> ==Breeding== [[Image:Salmoneggskils.jpg|thumb|230px|Very young fertilised salmon eggs; notice the developing [[eye]]s and [[vertebral column]].]] Atlantic salmon breed in the rivers of: Western [[Europe]] from Northern [[Portugal]] north to [[Norway]], [[Iceland]], [[Greenland]], and the east coast of [[North America]] from [[Connecticut]] in the [[United States]] north to northern [[Labrador]] and Arctic [[Canada]]. Atlantic salmon which have escaped from the [[aquaculture]] industry have also been found breeding in rivers tributary to the Pacific Ocean in [[British Columbia]] on Canada's west coast. At sea, the species is found mainly in the waters off Greenland and in migrations to and from its natal streams.<ref name="Shearer"/> Until the early 1800s, Atlantic salmon were native to the waters of central New York. When dams were constructed on the [[Oswego River]] their spawning areas were cut off and they went [[extinct]] in the area. Unlike the various Pacific salmon species, the Atlantic salmon is [[iteroparous]], which means the fish does not automatically die after spawning, and may recondition themselves, return to the sea to repeat the migration and spawning pattern several times.<ref name="Heen">{{cite book |author=Heen, K |title=Salmon Aquaculture |publisher=Halstead Press |year=1993}}</ref><ref name="Audubon"/> Nevertheless, migration and spawning exact an enormous physiological toll on the individual fish, such that repeat spawners are the exception rather than the norm.<ref name="Heen"/> ==Aquaculture== In its natal streams, Atlantic salmon are considered a prized recreational fish, pursued by avid [[fly fishing|fly anglers]] during its annual runs. At one time, the species supported an important commercial fishery and a supplemental food fishery. However, the wild Atlantic salmon fishery is commercially dead; after extensive habitat damage and overfishing, wild fish make up only 0.5% of the Atlantic salmon available in world fish markets. The rest are farmed, predominantly from [[aquaculture]] in [[Chile]], Canada, Norway, [[Russia]], the [[United Kingdom|UK]] and [[Tasmania]] in [[Australia]]. [[Sport fishing]] communities, mainly from Iceland and [[Scandinavia]], have joined in the North Atlantic Salmon Fund (NASF) to buy away commercial quotas in an effort to save the wild species of ''Salmo salar''.<ref name="Heen"/> ===Aquaculture techniques=== [[Image:Salmon farming.jpg|250px|thumb|An Atlantic salmon farm which holds yearlings for up to two years. Many hold [[broodstock]] for even longer in these conditions to help ensure large, [[animal sexuality|sexually mature]] adults.]] Adult male and female fish are [[anesthesia|anaesthetised]]. Eggs and sperm are "stripped", after the fish are cleaned and cloth dried. Sperm and eggs are mixed, washed, and placed into fresh water. Adults recover in flowing, clean, well [[aeration|aerated]] water.<ref name="Sedgwick">{{cite book |author=Sedgwick, S |title=Salmon Farming Handbook |publisher=Fishing News Books LTD |year=1988}}</ref> Some researchers have even studied cryopreservation of their eggs. <ref>{{cite book |author=N. Bromage |title=Broodstock Management and Egg and Larval Quality |publisher=[[Blackwell Science]] |year=1995}}</ref> Fry are generally reared in large freshwater tanks for 12 to 20 months. Once the fish have reached the smolt phase, they are taken out to sea where they are held for up to two years. During this time the fish grow and mature in large cages off the coasts of Canada, the USA, or parts of Europe.<ref name="Heen"/> Generally, cages are made of two nets. Inner nets, which wrap around the cages, hold the salmon. Outer nets, which are held by floats, keep predators out.<ref name="Sedgwick"/> ===Controversy=== Many Atlantic salmon escape from cages at sea. Those salmon who further breed tend to lessen the [[genetics|genetic]] diversity of the species leading to lower survival rates, and lower catch rates. On the West Coast of Northern America, the non-native salmon can be an invasive threat, especially in [[Alaska]] and parts of Canada. This causes them to compete with native salmon for resources. Extensive efforts are underway to prevent escapes and the spread of Atlantic salmon in the Pacific and elsewhere.<ref name="Mills"/> ==Human impact== Salmon decline in [[Lake Ontario]] goes back to the 1700s-1800s, due to logging, soil erosion, as well as dam and mill construction. By 1896 the species was declared extirpated from the lake.<ref>Harb, M. "Upstream Battle", ''Canadian Geographic Magazine'', June 2008, p. 24</ref> In the 1950s it was discovered that salmon from rivers in the US and Canada, as well as from Europe, gathered in the sea around [[Greenland]] and the [[Faroe Islands]]. A massive commercial fishing industry was established, taking salmon in [[drift net]]s. After an initial series of record annual catches, the numbers crashed: between 1979 and 1990, catches fell from four million to 700,000.<ref>{{cite news |publisher=[[BBC News]] ||title=Salmon campaigner lands top award |date=[[2007-04-22]] |url=http://news.bbc.co.uk/1/hi/sci/tech/6571241.stm}}</ref> Currently, overfishing, habitat loss and aquacultured salmon escapes are the greatest threats to natural Atlantic salmon populations. In [[New England]], many efforts are underway to restore salmon to the region by knocking down obsolete dams and updating others with [[fish ladder]]s 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]]. In [[Ontario]], the [http://www.bringbackthesalmon.ca/ Atlantic Salmon Restoration Program] was started in 2006 and is one of the largest freshwater conservation programs in North America. It has stocked [[Lake Ontario]] with over 700,000 young Atlantic salmon. In November 2007, a migrating salmon was observed in the [[Credit River]].<ref>Harb, M. "ibid", p. 24</ref> There has also been some success in establishing Atlantic salmon in Fish Creek, a tributary of [[Oneida Lake]] in central New York. Atlantic salmon however, remains a popular fish for human consumption.<ref name="Audubon"/> It is commonly sold fresh, canned, or frozen. ==Legislation== The first laws regarding the Atlantic salmon were started nearly 800 years ago. ===England and Wales=== [[Edward I of England|Edward I]] instated a penalty for collecting salmon during certain times of the year. His son [[Edward II of England|Edward II]] continued, regulating the construction of [[weir]]s. Enforcement was overseen by those appointed by the [[Justices of the Peace]]. Because of confusing laws, and the fact that the appointed conservators had little power, most laws were barely enforced. Based upon this, in 1860 a Royal Commission was appointed to thoroughly investigate the Atlantic Salmon and the laws governing the species. The results caused the 1861 [[Salmon Fisheries Act]]. The Salmon Fisheries Act placed control of enforcing the laws under the [[Home Office]]'s control. Control however was later taken from the Home Office, and transferred to the [[Board of Trade]] and then later to the [[Minister of Agriculture, Fisheries and Food|Board of Agriculture and Fisheries]]. Another act was later passed in 1865 that imposed charges to fish and catch limits. It also caused the formation of local boards that had jurisdiction over a certain river. The next significant act was passed in 1907 which allowed board to charge 'duties' to catch other freshwater fish, including trout. Despite legislation, board decreased until in 1948 the [[River Boards Act]] gave authority of all freshwater fish and also the prevention of pollution to one board per river. In total it created 32 boards altogether. In 1974, all the 32 boards were reduced to 10 regional water authorities (RWAs). Although only the [[Northumbria]]n, [[Welsh Water Authority|Welsh]], north west and south west RWA's had considerable salmon population, all ten also cared for trout and [[freshwater eel]]s. The [[Salmon and Freshwater Fisheries Act]] was passed in 1975. Among other things, it regulated [[fishing licence]]s, fishing seasons, size limits, and banned obstructing the salmon's migratory paths.<ref name="Shearer"/> ===Scotland=== Legislation in [[Scotland]] to help Atlantic salmon began in 1318 by [[Alexander II of Scotland|Alexander II]]. It prohibited certain types of traps in rivers. During the 15th century many laws were passed, many that regulated fishing times, and worked to ensure smolts could safely pass downstream. [[James III of Scotland|James III]] even closed a [[flour|meal]] [[watermill|mill]] because of its history of killing fish attracted to the [[wheel]]. Because the fish was held in such high regard, [[poaching|poachers]] were severely punished. More recent legislation has established commissioners who manage districts. Furthermore, the [[Salmon and Freshwater Fisheries Act]] in 1951 required that the [[Secretary of State for Scotland|Secretary of State]] be given data about the catches of salmon and trout to help establish catch limits.<ref name="Shearer"/><ref name="Sedgwick"/> ===United States=== Fishing in the [[United States]] is controlled by the [[United States Fish and Wildlife Service]], and by NOAA Fisheries. The only act targeting the fish is the [[Atlantic Salmon Convention Act of 1982]] which makes sure the [[United States Secretary of State|Secretary of State]]<!--Secretary of STATE?? perhaps Sec of Interior or Agriculture, I think.--> receives reports, recommendations about laws regarding the species, and proposals from the group. Several populations of Atlantic Salmon are in serious decline, and are listed as threatened under the Endangered Species Act. ===Quebec=== In Quebec, the daily catch limit for Atlantic salmon is 1 fish over 63&nbsp;cm, 2 fish under 63&nbsp;cm or 1 fish over and 1 under 63&nbsp;cm, provided that the smaller fish was the first one caught (a provision designed to prevent an angler from continuing to fish if a large fish is already in possession). The annual catch limit is 7 Atlantic salmon of any size. ==NASCO== The [[North Atlantic Salmon Conservation Organization]] (NASCO) is an international council made up of Canada, Denmark, the [[European Union]], Iceland, Norway, the [[Russia|Russian Federation]], and the United States, with its headquarters in [[Edinburgh]] [http://www.nasco.int/]. It was established in 1983 to help protect Atlantic salmon stocks, through the cooperation between nations. They work to restore habitat and promote conservation of the salmon. ==References== <!-- ---------------------------------------------------------- See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a discussion of different citation methods and how to generate footnotes using the <ref>, </ref> and <reference /> tags ----------------------------------------------------------- --> {{reflist}} ==Sources== *{{IUCN2006|assessors=World Conservation Monitoring Centre|year=1996|id=19855|title=Salmo salar|downloaded=[[12 May]] [[2006]]}} *{{ITIS|ID=161996|taxon=Salmo salar|year=2006|date=30 January}} *{{FishBase_species|genus=Salmo|species=salar|year=2005|month=10}} ==External links== <!-- Please ensure that any links added here conform to the guidelines in [[WP:LINKS]] and [[WP:COI]] --> *[http://www.maine.gov/asc/ State of Maine, Atlantic Salmon Commission] *[http://www.bio.umass.edu/biology/conn.river/salmon.html University of Massachusetts information regarding Atlantic salmon] *[http://www.worldwildlife.org/salmon/ Atlantic salmon's page on World Wide Fund for Nature's website] *[http://www.adfg.state.ak.us/special/as/as_home.php Alaska Fish and Game Atlantic salmon page] *[http://www.atlanticsalmontrust.org/ Atlantic Salmon Trust, an organization working to protect the Atlantic salmon] *[http://www.atlanticsalmonfishing.ca/ Atlantic Salmon Fishing, Information about Atlantic Salmon Fishing] *[http://www.mnr.gov.on.ca/en/Newsroom/LatestNews/MNR_E004275.html/ Ontario Ministry of Natural Resources, Information About Atlantic Salmon Restoration Program] *[http://www.wilsonscamps.nb.ca/ Atlantic Salmon Fishing Reports & Images] [[Category:Salmo]] [[Category:Salmon]] [[Category:Arctic freshwater fish]] [[Category:Introduced freshwater fish of New Zealand]] [[Category:Fish of Europe]] [[Category:Fish of the Atlantic]] [[Category:Cold water fish]] [[Category:Fauna of Greenland]] [[Category:Commercial fish]] [[Category:Fly fishing target species]] [[cs:Losos obecný]] [[cy:Eog]] [[da:Laks]] [[de:Atlantischer Lachs]] [[es:Salmo salar]] [[eu:Izokin]] [[fr:Saumon atlantique]] [[gl:Salmón atlántico]] [[it:Salmo salar]] [[lt:Atlantinė lašiša]] [[nl:Atlantische zalm]] [[ja:タイセイヨウサケ]] [[no:Atlanterhavslaks]] [[pl:Łosoś szlachetny]] [[ru:Сёмга]] [[se:Luossa]] [[sr:Лосос]] [[fi:Lohi]] [[sv:Lax]] [[tr:Atlantik somonu]]