Muskellunge / le maskinongéThe 85 species of fish documented to inhabit the Ottawa River live in turbid to slow moving waters, deep lakes, wetlands and shallow bays: each of these fish species are adapted to specific features of the river. As a result, not all species can be found in each section of the river. The various ecosystems of the Ottawa River offer habitat for spawning, nurseries and rearing. The distribution and abundance of fish varies based on the habitat and the location. In general, the most diverse fish communities exist in the shallow shoreline areas; both warmwater and coldwater fish communities are found here. North of Lac La Cave, most fish species are coldwater.

The diversity and the distribution of fish species have been significantly affected by development of the Ottawa River, particularly by hydroelectric generation. Hydro dams have blocked migratory species, such as the American Shad and Eels, to such an extent that they are now very low in numbers or absent from the river (See the Threatened Species section).

Muskellunge and Pike are known to spawn in the Ottawa River’s numerous wetlands. These two species play an important role in the food web of wetland ecosystems: they are fierce predators. When wetlands are filled in for agriculture and urban development, their populations diminish. Industrial pollution may also impact on their populations.

Walleye may spawn in turbid areas. Walleye are known to spawn below dams in tributaries as well as along the Ottawa River. Since their passage is blocked by dams, they are numerous downstream of dams, but relatively scarce upstream. Sauger, a species similar to Walleye, can be found in the same habitats and is know to occasionally hybridize with Walleye.

Source: The Ottawa River Background Study by the Ottawa River Heritage Designation Committee.