Report a discovery in an unlisted area
If you think you’ve seen or caught a Largemouth Bass:
- Do not release it into the water.
- Catch it and keep it frozen. If you can’t do that, destroy it.
- Note the location (with GPS coordinates if possible) as well as the observation date.
- Contact Fisheries and Oceans Canada.
- a robust body, less laterally compressed than the smallmouth bass
- a large, long, head with a deep wide dorsal surface
- a long, blunt snout not as deep as that of smallmouth bass
- a large, wide lower jaw slightly longer than the upper jaw
- can have a broken horizontal stripe along the side of the body
- two joined dorsal fins, with separation more obvious than in smallmouth bass
- the back and top of the head are bright green to olive
- the sides of the head are olive to golden green with some scattered black pigment and the underside is white to yellow
- the dorsal and caudal fins are opaque, green to olive; the anal and pelvic fins are green to olive with some white; the pectoral fins are amber and clear
- populations that live in clear, weedy water are darker and the black pigment is more obvious than those that live in dark, turbid water, which are a pale green colour overall.
Adult Largemouth Bass are largely fish-eating predators, but food type changes as they grow: from plankton to insects, fish, crayfish, and frogs. The Largemouth Bass is a visual feeder and takes food from the surface, in the water column, and off the bottom. It often feeds in schools near shore, close to vegetation.
Where it has been found
Largemouth Bass are native to North America, and its native range was generally restricted to the fresh waters of eastern-central North America including the lower Great Lakes. Largemouth Bass is a freshwater fish that has currently, a distribution similar to the smallmouth bass in Canada, although it is not found in New Brunswick, Nova Scotia, or Prince Edward Island and probably not in Newfoundland. It is probably best known in the Kawartha and Rideau Lakes in Ontario. In B.C., Largemouth Bass are found in the Columbia River system including, Vaseaux, Osoyoos, Christina and Kootenay lakes.
The habitat of Largemouth Bass is the upper levels of the warm water of small, shallow lakes and shallow bays of larger lakes. It is almost always found close to soft bottoms, stumps, and extensive growths of a variety of emergent and sub-emergent vegetation, especially waterlilies, cattails, and other pondweeds. Because it is rarely found in the rocky areas favoured by smallmouth bass, the habitats of largemouth and smallmouth bass seldom overlap, even though the two species often occur in the same lake.
Ecological and economic impacts
Largemouth Bass is a fish-eating predator though its diet varies from plankton to frogs as it matures. Though a popular sportfish, in some areas it can be invasive when introduced to new lakes. After introduction, this species has the potential to dramatically change the native food web and may cause the extinction of native species.
Origins and mode of arrival
Native to North America
Largemouth Bass is now one of the most widely distributed freshwater fishes in the world, mainly because of its popularity as a sports fish. Its North American expansion started in the late 1800s, aided by extensive stocking and the species’ adaptable nature.
Mode of dissemination
Largemouth Bass has success as invader in part due to his dietary flexibility; it’s as voracious piscivorous species that start consuming fish at a small size. Moreover, this species can tolerate high temperatures and slight turbidity and has a fast growth rate, which allows the introduced specimens of Largemouth Bass to become established easier. However, the reproductive behaviour of Largemouth Bass requires specific conditions and if those conditions are not met it may prevent its establishment.
Fisheries and Oceans Canada is studying the Largemouth Bass population to improve its understanding of how it reacts and adapts to Canadian conditions.
For further information
- Canadian Science Advisory Secretariat (CSAS) Publications
- Biological Synopsis of Largemouth Bass
Canadian Manuscript Report of Fisheries and Aquatic Sciences 2884, 2009 – Fisheries and Oceans Canada
- Biological Risk Assessment for Smallmouth bass (Micropterus dolomieu) and Largemouth Bass (Micropterus salmoides) in British Columbia.
Research document – 2008/075 – Fisheries and Oceans Canada
- Workshop Proceedings
- Science Advisory Report
- Brown, T.G., Runciman, B., Pollard, S., and Grant, A.D.A. 2009. Biological synopsis of Largemouth Bass (Micropterus salmoides). Can. Manuscr. Rep. Fish. Aquat. Sci. 2884: v + 27 p.
- Tovey, C. P., Bradford, M. J., Herborg, L. M., & Department of Fisheries and Oceans, Ottawa, ON (Canada); Canadian Science Advisory Secretariat, Ottawa, ON (Canada). (2009). Biological risk assessment for smallmouth bass (Micropterus dolomieu) and Largemouth Bass (Micropterus salmoides) in British Columbia (No. 2008/075). DFO, Ottawa, ON (Canada).
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