Salvelinus namaycush
Lake Trout
NS
G5
Collection Details
Specimens
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Records
Taxonomic Hierarchy
Actinopterygii (Ray-finned Fishes)
Salmoniformes
Salmonidae (Trouts and Salmons)
Salvelinus
Salvelinus namaycush (Lake Trout)
Description
This species account was compiled from
FishBase (Froese, R. and D. Pauly. Editors. 2025. FishBase. World Wide Web electronic publication. www.fishbase.org, version 04/2025.)
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Characters
Body shape: fusiform / normal. Distinguished by its color, white or yellowish spots on a dark green to grayish background, its deeply forked tail and its numerous pyloric caeca. Lateral line slightly curved anteriorly; pelvic fins with small axillary process (Ref. 27547). Body typically trout-like, elongate, somewhat rounded. Head stout, broad dorsally; mouth large, terminal, snout usually protruding slightly beyond lower jaw when mouth is closed. Back and sides usually dark green liberally sprinkled with whitish to yellowish (never pink or red) spots; overall color varies from light green to gray, brown, dark green or nearly black; belly white; pale spots present on dorsal, adipose and caudal fins and usually on base of anal; sometimes orange-red on paired fins, especially in northern populations; anterior edge of paired and anal fins sometimes with a white border. At spawning time, males develop a dark lateral stripe and become paler on the back (Ref. 27547). Caudal fin with 19 rays (Ref. 2196). Distinguished from congeners in Europe by the unique dark brown head, body, dorsal and caudal fins, covered by small pale spots; differs also by its deeply forked caudal fin (Ref. 59043). Striking features: none.
Distribution
North America: Atlantic, Arctic, and Pacific basins from northern Canada and Alaska south to New England in USA, Great Lakes, and northern Montana, 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).
Habitat Associations
Freshwater. benthopelagic. depth range 3-61 m. Found in: streams, lakes.
Biology
Occurs 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, 86798). Rarely found 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). Lake trout are highly susceptible to pollution, especially from insecticides (Ref. 14019, 27547). Utilized as a food fish, its flesh is usually of a yellow or creamy color but may be anything from white to orange (Ref. 27547). Often caught by fishers (Ref. 30578).
Max length: 150.0 cm TL; common length: 50.0 cm TL; max weight: 32650 g; max age: 50 years.
Reproductive mode: dioecism; fertilization: external; nonguarders (open water/substratum egg scatterers); parental care: none. The spawning act occurs mostly at night, with peak activity between dusk and 9 or 10 pm (Ref. 28805, 28815). During the day the fish are more or less dispersed away from the spawning beds but return in considerable numbers in the late afternoon (Ref. 27547). Males reach spawning beds first and spend some time cleaning the rocks. Females arrive a few days later and are courted by the males. During and following courtship, the males attempt to spawn with the females. One or two males approach a female, press against her sides and quiver. The eggs fall into the crevices and the spawners disperse. The act is repeated until the female releases all her eggs (Ref. 1998, 27547). On occasion, as many as seven males and three females may engage in a mass spawning act (Ref. 28815). Spawning occurs annually in southern areas, every other year in Great Slave Lake, Northwest Terrritories, and only every other year in Great Bear and some other lakes of the arctic (Ref. 1153, 28802, 28860).
IUCN Red List Status: Least Concern (LC), assessed 2020-09-05. Resilience: Low (K=0.05-0.12; tm=5-20; tmax=50; Fec=5,000).
Commercial or Environmental Importance
Fisheries: commercial; gamefish; aquaculture: commercial.
References
Breder, C.M. and D.E. Rosen (1966) Modes of reproduction in fishes. T.F.H. Publications, Neptune City, New Jersey. 941 p.
Scott, W.B. and E.J. Crossman (1973) Freshwater fishes of Canada. Bull. Fish. Res. Board Can. 184: xi+1-966.
Morrow, J.E. (1980) The freshwater fishes of Alaska. University of. B.C. Animal Resources Ecology Library. 248p.
Jude, D.J., F.J. Tesar, S.F. Deboe and T.J. Miller (1987) Diet and selection of major prey species by Lake Michigan salmonids, 1973-1982. Trans. Am. Fish. Soc. 116(5):677-691.
Keith, P. and J. Allardi (coords.) (2001) Atlas des poissons d'eau douce de France. Muséum national d’Histoire naturelle, Paris. Patrimoines naturels, 47:1-387.
IGFA (2001) Database of IGFA angling records until 2001. IGFA, Fort Lauderdale, USA.
Page, L.M. and B.M. Burr (2011) A field guide to freshwater fishes of North America north of Mexico. Boston : Houghton Mifflin Harcourt, 663p.
Michigan Department of Natural Resources (2019) Lake trout. https://www.michigan.gov/dnr/0,8817,7-350-79135_79218_79614_82519---,00.html. Accessed 4/2019.
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