The lake trout (''Salvelinus namaycush'') is a freshwater char living mainly in lakes in Northern North America. Other names for it include mackinaw, namaycush, lake char (or charr), touladi, togue, laker, and grey trout. In

Lake Superior Lake Superior is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. Lake Michigan–Huron has a larger combined surface area than Superior, but is normally considered tw ...

, it can also be variously known as siscowet, paperbelly and lean. The lake trout is prized both as a

game fish Game fish, sport fish or quarry refer to popular fish species pursued by recreational fishing, recreational fishers (typically angling, anglers), and can be freshwater fish, freshwater or saltwater fish. Game fish can be fish as food, eaten aft ...

and as a food fish. Those caught with dark coloration may be called ''mud hens''.

Taxonomy and etymology

It is the only member of the subgenus ''Cristovomer'', which is more derived than the subgenus '' Baione'' (the most basal clade of ''Salvelinus'', containing the

brook trout The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae native to Eastern North America in the United States and Canada. Two ecological forms of brook trout h ...

(''S. fontinalis'') and silver trout (''S. agasizii'')) but still basal to the other members of ''Salvelinus''. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''namaycush'' derives from ''namekush'', a form of the word used in some inland Southern East Cree communities in referring to this species of fish. Other variations found in East Cree are ''kûkamâs ', ''kûkamâw'' and ''kûkamesh''. Similar cognate words are found in

Ojibwe The Ojibwe (; Ojibwe writing systems#Ojibwe syllabics, syll.: ᐅᒋᐺ; plural: ''Ojibweg'' ᐅᒋᐺᒃ) are an Anishinaabe people whose homeland (''Ojibwewaki'' ᐅᒋᐺᐘᑭ) covers much of the Great Lakes region and the Great Plains, n ...

: ''namegos'' = "lake trout"; ''namegoshens'' = "rainbow trout," literally meaning "little lake trout."

Range

From a zoogeographical perspective, lake trout have a relatively narrow distribution. They are native only to the northern parts of North America, principally Canada, but also

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

and, to some extent, the Northeastern United States. Lake trout have been widely introduced into non-native waters in North America and into many other parts of the world, mainly Europe, but also into South America and certain parts of Asia. Although lake trout were introduced into

Yellowstone National Park Yellowstone National Park is a List of national parks of the United States, national park of the United States located in the northwest corner of Wyoming, with small portions extending into Montana and Idaho. It was established by the 42nd U ...

Shoshone The Shoshone or Shoshoni ( or ), also known by the endonym Newe, are an Native Americans in the United States, Indigenous people of the United States with four large cultural/linguistic divisions: * Eastern Shoshone: Wyoming * Northern Shoshon ...

, Lewis and Heart lakes legally in the 1890s, they were illegally or accidentally introduced into Yellowstone Lake in the 1980s where they are now considered invasive. They have also notably been introduced into the Tahoe region, such as in

Lake Tahoe Lake Tahoe (; Washo language, Washo: ''dáʔaw'') is a Fresh water, freshwater lake in the Sierra Nevada of the Western United States, straddling the border between California and Nevada. Lying at above sea level, Lake Tahoe is the largest a ...

and Donner Lake.

Description

Lake trout have a common

Salmonidae Salmonidae (, ) is a family (biology), family of ray-finned fish, the only extant member of the suborder Salmonoidei, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmo ...

body, with an elongated figure, a single dorsal and adipose fin, and lack spines on any of their fins. The pattern of lake trout is a uniform olive-grey, darker near the back, and white on the belly. They are covered in light beige or white spots along the body. The fins are yellow-ish, and may have white tips. During spawning, the belly becomes more yellow-orange, and the fins develop a red hue with more developed white edges. They have small but sharp teeth, which are more visible compared to other species of trout during non-spawning periods. Lake trout are the largest of the chars; the record weighed almost with a length of , and was caught with a

gillnet Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...

. fish are not uncommon, and the average length is . The largest caught on a rod and reel according to the

IGFA The International Game Fish Association (''IGFA'') is the leading authority on angling pursuits and the keeper of the most current world record fishing catches by fish categories. Fishermen who are sport fishers and anglers are careful to follow ...

was , caught in Great Bear Lake in 1995 with a length of . In the Tahoe region, the fish do not exceeded , but are on average over .

Life history

Lake trout inhabit cold, oxygen-rich waters. They are

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

during the period of summer stratification in dimictic lakes, often living at depths of . The lake trout is a slow-growing fish, typical of oligotrophic waters. It is also very late to mature. Populations are extremely susceptible to

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...

. Many native lake trout populations have been severely damaged through the combined effects of hatchery stocking (planting) and over harvest. Another threat to lake trout is acidification, which can have longterm effects on their populations through both direct harm and reduced prey populations (e.g. '' Mysis relicta''). Lamprey

There are three

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of lake trout. There is the common lake trout (''Salvelinus namaycush namaycush''), the siscowet lake trout (''Salvelinus namaycush siscowet''), and the less common rush lake trout (''Salvelinus namaycush huronicus''). Some lakes do not have

forage fish Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons (i.e. planktivores) and other small aquatic organisms (e.g. krill). They are in turn preyed upon by various predators including larger fish, seabirds ...

during the period of summer stratification. In these lakes, lake trout act as

planktivore A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and i ...

s. Lake trout in planktivorous populations are highly abundant, grow very slowly and mature at relatively small sizes. In those lakes that do contain deep-water forage, lake trout become

piscivorous A piscivore () is a carnivorous animal that primarily eats fish. Fish were the diet of early tetrapod evolution (via water-bound amphibians during the Devonian period); insectivory came next; then in time, the more terrestrially adapted rept ...

. Piscivorous lake trout grow much more quickly, mature at a larger size and are less abundant. Notwithstanding differences in abundance, the density of

biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...

of lake trout is fairly consistent in similar lakes, regardless of whether the lake trout populations they contain are planktivorous or piscivorous. In

, common lake trout (''S. n. namaycush'') and siscowet lake trout (''S. n. siscowet'') live together. Common lake trout tend to stay in shallower waters, while siscowet lake trout stay in deeper water. Common lake trout (also called "lean" lake trout) are slimmer than the relatively fat siscowet. Siscowet numbers have become greatly depressed over the years due to a combination of the

extirpation Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with extinction, global extinctions. Local extinctions ...

of some of the fish's deep water coregonine prey and to

overexploitation Overexploitation, also called overharvesting or ecological overshoot, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to ...

. Siscowet tend to grow extremely large and fat and attracted great commercial interest in the last century. Their populations have rebounded since 1970, with one estimate putting the number in Lake Superior at 100 million. Professor of Zoology at the

University of Wisconsin-Madison A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Uni ...

James Kitchell credits effective constraint of commercial fisheries and persistent sea lamprey (''Petromyzon marinus'') control for the successful recovery of Lake Superior's lake trout. "Looking at what has happened in the lake and the results of computer simulations, it is clear that lamprey control needs to continue if Lake Superior is to keep its lake trout."

Hybrids

Lake trout are known to hybridize in nature with the

(''S. fontinalis''); such hybrids, known as " splakes" (between a male brook and female lake trout) or the less common "brookinaw" (between a male lake and female brook trout,) are normally sterile but self-sustaining populations exist in some lakes. Splake are also artificially propagated in hatcheries, and then stocked into lakes in an effort to provide sport-fishing opportunities.

Commercial fishing

Lake trout were fished commercially in the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...

until lampreys, overharvest and pollution

extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...

or severely reduced the

stocks Stocks are feet and hand restraining devices that were used as a form of corporal punishment and public humiliation. The use of stocks is seen as early as Ancient Greece, where they are described as being in use in Solon's law code. The law de ...

. Commercial fisheries still exist in some areas of the Great Lakes and smaller lakes in northern Canada. Commercial fishing by Ottawa (

Odawa The Odawa (also Ottawa or Odaawaa ) are an Indigenous North American people who primarily inhabit land in the Eastern Woodlands region, now in jurisdictions of the northeastern United States and southeastern Canada. Their territory long prec ...

) and Chippewa (

) Indians for Lake Trout in Lake Michigan, Lake Huron and

is permitted under various

treaties A treaty is a formal, legally binding written agreement between sovereign states and/or international organizations that is governed by international law. A treaty may also be known as an international agreement, protocol, covenant, convention ...

and co-managed and regulated by many tribes and Great Lakes Indian Fish & Wildlife Commission (GLIFWC).

Popular culture

Geneva Geneva ( , ; ) ; ; . is the List of cities in Switzerland, second-most populous city in Switzerland and the most populous in French-speaking Romandy. Situated in the southwest of the country, where the Rhône exits Lake Geneva, it is the ca ...

, New York claims the title "Lake Trout Capital of the World," and holds an annual lake trout fishing derby. Baraga county in

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

also hosts an annual "lake trout festival" in June.

References

External links

Fishbase description of Lake trout
{{Authority control

Lake trout The lake trout (''Salvelinus namaycush'') is a freshwater Salvelinus, char living mainly in lakes in Northern North America. Other names for it include mackinaw, namaycush, lake char (or charr), touladi, togue, laker, and grey trout. In Lake Sup ...

Freshwater fish of the United States Freshwater fish of the Arctic Lake fish of North America Fish of the Great Lakes

Taxa named by Johann Julius Walbaum