Lake trout
(Salvelinus namaycush
) is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw
, lake char
(or charr
), touladi
, togue
, and grey trout
. In Lake Superior, they can also be variously known as siscowet
, paperbellies
and leans
. Lake trout are prized both as game fish and as food fish.
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LAKE TROUT TICKETS
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Range
From a
zoogeographical perspective, lake trout are quite rare. They are native only to the northern parts of
North America, principally
Canada but also
Alaska and, to some extent, the northeastern
United States. The southern extreme of the Lake trout's range extends into southern New York at Kensico Reservior where a self sustaining population has existed since the 1950's. Lake trout have been introduced into many other parts of the world, mainly into
Europe but also into
South America and certain parts of
Asia. In Canada, approximately 25% of the world's lake trout lakes are found in the province of
Ontario. Even at that, only 1% of Ontario's lakes contain lake trout.
Description
Lake trout are the largest of the charrs, the record weighing almost 46.3
kg (102
lb).
Life history
Lake trout are dependent on cold, oxygen-rich waters. They are
pelagic during the period of
summer stratification in
dimictic lakes, often living at depths of 20–60 m (60–200 ft).
The lake trout is a slowly growing fish, typical of
oligotrophic waters. It is also very late to mature. Populations are extremely susceptible to overexploitation. Many native lake trout populations have been severely damaged through the combined effects of
hatchery stocking (planting) and overharvest.
It is generally accepted that there are two basic types of lake trout populations. Some lakes do not have
pelagic forage fish during the period of summer stratification. In these lakes, lake trout take on a life history known as
planktivory. Lake trout in planktivorous populations are highly abundant, grow very slowly and
mature at relatively small size. In those lakes that do contain deep water forage, lake trout become
piscivorous. Piscivorous lake trout grow much more quickly, mature at a larger size and are less abundant. Notwithstanding differences in abundance, the
density of
biomass of lake trout is fairly consistent in similar lakes, regardless of whether the lake trout populations they contain are planktivorous or piscivorous.
In
Lake Superior, three distinct
phenotypes of lake trout persist, commonly known as "siscowet", "paperbelly" and "lean". The distinct groups operate, to some level at least, under genetic control and are not mere environmental adaptations.
[1] Siscowet numbers, especially, have become greatly depressed over the years due to a combination of the extirpation of some of the fish's deep water
coregonine prey and to overexploitation. Siscowet tend to grow extremely large and fat and attracted great commercial interest in the last century. Siscowet populations have rebounded since 1970, with one estimate putting the number in Lake Superior at 100 million.
[2]
Hybrids
Lake trout have been known, very rarely, to
hybridize in nature with the
brook trout, but such hybrids, known as "
splake", are almost invariably reproductively
sterile. Splake are also artificially propagated in hatcheries and then planted into lakes in an effort to provide sport fishing opportunities. These fish are easily distinguished from both lake and brook trout by the overlap of markings and coloration. A splake has bright orange fins with white tips and slightly white wormlike markings of a brook trout. Splake also have a longer lake trout jaw, teeth, dark purple back, and orientation of marks like a lake trout
Commercial fishing
Lake trout were
fished commercially in the
Great Lakes until
lampreys,
overharvest and pollution
extirpated or severely reduced the
stocks. Commercial fisheries still exist in some smaller lakes in northern
Canada.
Origin of name
The
specific epithet
namaycush
derives from an
indigenous North American name for the species, most likely in one of the
Algonquian languages (c.f.
Ojibwe:
namegos
= "lake trout";
namegoshens
= "rainbow trout").
In
Baltimore,
Maryland, the term "lake trout" is used to refer to a popular
fast food sandwich of fried Atlantic
whiting.
[3]
References
- Burnham-Curtis, M.K. and G.R. Smith, 1994. Osteological evidence of genetic divergence of lake trout (Salvelinus namaycush) in Lake Superior. Copeia (4):845-850.
- Siscowet Trout: A Plague of Riches
- Baltimore City Paper: Lake Trout in West Baltimore