| Lake whitefish | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Salmoniformes |
| Family: | Salmonidae |
| Genus: | Coregonus |
| Species: | C. clupeaformis |
| Binomial name | |
| Coregonus clupeaformis (Mitchill, 1818) |
|
The lake whitefish (Coregonus clupeaformis), also called the Sault whitefish or gizzard fish, is a species of freshwater whitefish from North America.[1] Lake whitefish are found throughout much of Canada and parts of the northern United States, including all of the Great Lakes. A valuable commercial fish, they are also occasionally taken by sport fishermen. Smoked, refrigerated, vacuum-packed lake whitefish fillets are now commonly available in North American grocery stores.
Their colouration is olive-green to blue on the back, with silvery sides. They have a small mouth below a rounded snout, and a deeply forked tail. On average, they reach 17 to 22 inches and weigh 1.5 to 4 pounds. They are found in freshwater lakes where they prefer deep, cool water.
Lake whitefish spawn from September through January in water two to four metres in depth. 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 388 km (241 mi), from Fort McMurray to the north shore of Lake Athabasca in Alberta, Canada.
The lake whitefish is considered Least Concern on the IUCN Red List list. However, the distinct stock called Lake Simcoe Whitefish is considered a threatened species in Canada. [2]
Natural predators include burbot, lake trout and northern pike.
Primarily bottom feeders, lake whitefish eat crustaceans, snails, insects, and other small aquatic organisms.
Since the end of the last glaciation (about 12000 years ago), whitefish have been able to re-colonize many North American lakes. As they invaded those environments, they have also diversified into different populations, such that they are now two main ecotypes 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.