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Species
Salvelinus namaycush (Walbaum, 1792)
IUCN
NCBI
EOL Text
North America: Widely distributed from northern Canada and Alaska south to New England in USA and Great Lakes basin in Canada-USA. Introduced widely to many areas outside its native range. Splakes (hybrid between Salvelinus namaycush and Salvelinus fontinalis) have also been successfully introduced to many areas of North America. The three observed phenotypes existing in Lake Superior (lean, siscowet and humper or paperbelly) are under some genetic control and not merely expressions of environmental adaptation (Ref. 40529).
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Rights holder/Author | Susan M. Luna, FishBase |
Source | http://www.fishbase.org/summary/SpeciesSummary.php?id=248 |
Found in shallow and deep waters of northern lakes and streams and is restricted to relatively deep lakes in the southern part of its range (Ref. 5723). Rarely in brackish water (Ref. 11980). A solitary wanderer, the extent of their movements apparently limited by the size of the lake and individual (Ref. 27547). Although lake trout generally feed on a variety of organisms such as freshwater sponges, crustaceans, insects, fishes (with a preference for ciscoes), and small mammals, some populations feed on plankton throughout their lives (Ref. 27547). Such plankton-feeding lake trout grow more slowly, mature earlier and at smaller size, die sooner and attain smaller maximum size than do their fish-eating counterparts (Ref. 30351). Juveniles feed on invertebrates (Ref. 1998).
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Pascualita Sa-a, FishBase |
Source | No source database. |
The commercial lake trout fishery in Lake Superior alone supported an annual commercial harvest of 2 million kg from 1920 to 1950. Overfishing and predation by the non-native sea lamprey, -Petromyzon marinus-, led to a sharp decline in the commercial take in the 1950's. Continued stocking since 1952, chemical control of the sea lamprey and the closing of the commercial fishery in the early 1960's has stabilized the population, but has not acheived the goal of restoring self-sustaining stocks that can support an annual harvest comparable to that of the 1930's and early 1940's. (Great Lakes Fishery Commission, 1996).
Success of the stocked fish has varied depending on the area. Due to this and other factors, the restoration plan for Lake Superior has changed from a program that concentrated heavily on stocking to a program that emphasized management of wild lake trout populations.
Continued mangement of the sea lamprey, stringent fishing controls and better survival of stocked fish will be key components of future restoration plans. (Great Lakes Fishery Commission, 1996).
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | ©1995-2013, The Regents of the University of Michigan and its licensors |
Source | http://animaldiversity.ummz.umich.edu/accounts/Salvelinus_namaycush/ |
Chile Central
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | Pablo Gutierrez, IABIN |
Source | No source database. |
Comments: Feeds opportunistically on various invertebrate and vertebrate animals. Zooplankton (Mysis and Pontoporeia crustaceans) important in diet of young; later, small benthic invertebrates are added to diet. Fishes, when available, are important in diet of adults (Scott and Crossman 1973), which may subsist on zooplankton when surface waters are too warm and fishes are absent in the deeper colder waters.
In Lake Superior, lean lake trout feed primarily on lake herring, rainbow smelt, and slimy sculpin; siscowet lake trout feed mostly on deepwater coregonines and deepwater sculpin (Harvey et al. 2003).
North America, introduced widely elsewhere.
As juveniles, lake trout feed on zooplankton and small invertebrates. As they mature, their foraging patterns shift and the fish become opportunistic piscivores.
As adults, lake trout are generally pisciverous, feeding on a wide variety of pelagic prey species. In the Great Lakes region, alewives, smelt, sculpin and chubs make up a large portion of the lake trout diet (Wisconsin Sea Grant, 1999).
Due to the cold water and dissolved oxygen content requirements of the species, lake trout which persist in the southern edge of their range must move to deeper water areas in the warmer summer months. If preffered prey species are not present at these depths, lake trout may then resort to feeding on zooplankton and invertebrates. In habitats that support no pelagic prey species, lake trout must subsist entirely on these secondary food sources. These dietary conditions often produce a leaner trout which grows more slowly and reaches sexual maturity earlier (Vander Zanden, 1999)
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | ©1995-2012, The Regents of the University of Michigan and its licensors |
Source | http://www.biokids.umich.edu/critters/Salvelinus_namaycush/ |
Rounded Global Status Rank: G5 - Secure
Lake trout possess a deeply forked caudal fin and a slate grey to greenish body with lighter undersides. Cream to yellow spots are generally present on the head, body and dorsal and caudal fins. The lower fins tend to be orange-red with a narrow white edge. Younger fish will have seven to twelve interrupted parr marks along their sides (Page, 1991). The species supports nine to twelve gill rakers and unlike their cousin the brook trout, -Salvelinus fontinalis-, lake trout do not have a black stripe on the anterior edge of their anal and pelvic fins (Wisconsin Sea Grant, 1999). Breeding males develop a dark, lateral stripe on their sides (Page, 1991).
Although an average weight of around 3kg is reported for this species, much larger fish are encountered, some weighing in excess of 27kg. These larger trout are thought to have lived for twenty years or more (Trout Angler's Society, 1999). Lake trout average 45 to 68cm in length, with unusual specimens reaching 126cm (Page, 1991).
Lake trout are known to hybridize with brook trout where the range of the two species overlap. The resulting hybrid, known as a splake, supports intermediate features.
Range mass: 0 to 0 kg.
Average mass: 3 kg.
Other Physical Features: bilateral symmetry
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | ©1995-2013, The Regents of the University of Michigan and its licensors |
Source | http://animaldiversity.ummz.umich.edu/accounts/Salvelinus_namaycush/ |