The lake whitefish ( Coregonus clupeaformis) is a species of freshwater whitefish from North America. Lake whitefish are found throughout much of Canada and parts of the northern United States, including all of the Great Lakes. The lake whitefish is sometimes referred to as a "humpback" fish due to the small size of the head in relation to the length of the body.[Roland Sigurdson (2011) Lake whitefish Minnesota Department of Natural Resources Species Profile. 19 April. 2012] It is a valuable commercial fish, and also occasionally taken by sport fishermen. Smoked, refrigerated, vacuum-packed lake whitefish fillets are available in North American grocery stores. Other vernacular names used for this fish include Otsego bass, Sault whitefish, gizzard fish, common whitefish, eastern whitefish, Great Lakes whitefish, humpback whitefish, inland whitefish and whitefish.
Etymology
The scientific genus name
Coregonus (co-regg'-on-us) means "angle eye" in Greek, and the species name
clupeaformis means "
herring-shaped" in Latin.
Description
Lake whitefish are similar in appearance to other whitefishes in the
Coregoninae subfamily of the salmon family
Salmonidae, such as the
northern cisco (
Coregonus artedi). As with all salmonids, they have an
adipose fin.
[ Lake Whitefish Identification. Minnesota Department of Natural Resources. 19 April 2012] To the distinction from cisco, the lake whitefish has a snout which overhangs the short lower jaw, so that the mouth opens in a slightly inferior position. Thus the fish can feed on the bottom of lake beds or grab food particulates out of the water or from the surface of a water body. The cisco in turn has a short snout with a lower jaw that extends beyond the snout. Both the cisco and lake whitefish are discernible from the
mooneye due to the small posterior dorsal
adipose fin.
[ Lake Whitefish Coregonus clupeaformis Michigan Department of Natural Resources. 19 April. 2012.] In early life stages however, the cisco and lake whitefish are indistinguishable based on morphological characters alone with genetic analyses being necessary to reliably identify species.
Another notable feature of the lake whitefish is the presence of two small flaps in each nostril.
[
] Their coloration is typically silver to white with an olive to pale-green or brown dorsal hues. The ventral fins are white and the tail has a dark posterior edge.
Lake whitefish from inland lakes can reach a weight upwards of ; the largest Lake Whitefish caught on rod and reel weighted 15 pounds 6 oz, from Clear Lake Ontario Canada on May 21, 1983, by Chris T. D. Webster according to the
Fresh Water Fishing Hall of Fame, in Hayward Wisconsin.[
] On average, the lake whitefish weighs only 4 pounds. They can grow to and commonly reach .
Life history
Habitat
Lake whitefish are cool water fish. They are found in a large number of inland lakes, and they have been known to enter brackish waters. The lake whitefish is distributed from
Alaska and western Canada to the Atlantic coastal drainage of
Maine and in
New Brunswick north to
Labrador.
Reproduction
Lake whitefish spawn from September through January in water two to four metres in depth during the night. In the autumn, mature lake whitefish enter the shallows to lay their eggs on shoals of rubble and gravel. There is no parental care of the young. In the following spring the young will hatch.
In northwestern Canada, a large spawning migration enters the Athabasca Delta in late summer, moving upstream in the
Athabasca River. The longest single movement of a tagged whitefish ever recorded was , from
Fort McMurray to the north shore of
Lake Athabasca in
Alberta, Canada.
Diet
Fish of
and postlarval stages feed on plankton. Once the larvae reach they switch to feeding on bottom-dwelling animals (
snail,
insect larvae,
zebra mussels, and
) which they will consume for the remainder of their lives.
In late June and July, some inland lake populations of ciscoes and lake whitefish leave the deep, cool waters to feast on emerging
mayflies and
midges.
The lake whitefish's natural predators include
burbot,
lake trout, and
northern pike.
Fishing
Commercial fishing
Lake whitefish is one of the most important species for commercial inland fisheries in North America. The total annual catch in 1999 from Canada was 8 328 t and USA 5 353 t reported by the
FAO.
Lake whitefish is the prime commercial species of the upper Great Lakes fishery, because this delicately flavored fresh fish has high local consumer acceptance. An average of 11 million pounds was harvested from the Great Lakes annually from 1981 to 1999. Although the harvest has declined from 9.5 to 8 million pounds in recent years, prices have not increased. Instead, the price for Great Lakes lake whitefish, which once reached as high as $1.04/lb., currently averages $.75/lb. and has dropped to as low as $.40/lb during periods of high production.
Sports fishing
Many amateur anglers also enjoy hooking this fish in the months of June, July and early August. A simple line and jig system is enough to catch the fish as they feast on mayflies and midges. In winter months, catching whitefish through the ice is very popular, particularly in northern Wisconsin, with many fishing guides specializing in this species. Successful icefishing techniques include using a jigging spoon, with at least one "slider hook" above and separated from the spoon with a barrel swivel, and all hooks tipped with wax worms. Commercial fishing has allowed for the spread of this fish into many different markets, restaurants, and grocery store shelves.
Conservation
A major threat to the lake whitefish is an
invasive species parasite species, the
sea lamprey. It is one of a number of species (in addition to the
lake trout and
Northern cisco) aggressively attacked by sea lamprey. In Lake Michigan the sea lamprey began to decimate indigenous fish populations in the 1930s and 1940s. It may have entered the Great Lakes region through the
Erie Canal which opened in 1825.
[ Nonindigenous Aquatic Species Factsheet: Petromyzon marinus U.S. Geological Survey (USGS), Nonindigenous Aquatic Species Program (NAS). Retrieved on 2007-08-04.] and spread even further in 1919 with improvements to the
Welland Canal from
Lake Ontario to
Lake Erie,
Lake Michigan,
Lake Huron, and
Lake Superior.
In Lakes Michigan and Huron, the invasive Quagga mussel poses a threat by filtering out the zooplankton that are the main food source for juvenile whitefish.
Evolution
Since the end of the last glaciation (about 12,000 years ago), whitefish have re-colonized many North American lakes, from different directions, from refugia that represent genetically diverged stocks or races. After the invasions, the whitefish have also diversified into different populations locally, such that now in many lakes two main
are recognized within the species: a normal and a dwarf ecotype. These normal and dwarf ecotypes are mainly differentiated by the
benthic and
pelagic zone they occupy, respectively. Normal whitefish also grow much bigger and live much longer than the dwarf ecotype.
Many of these populations live in sympatry, yet are reproductively isolated. The fact that they are young species makes them prime candidate to study the evolutionary forces driving their ecological divergence and reproductive isolation.
Notes
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