Habitat & Species
Aquatic habitat and species within the Mackenzie Great Bear sub-basin are undergoing moderate change. However, this assessment is primarily based on observations of changes in fish populations, health and fishing practices reported by Indigenous communities. Fish are considered key species for supporting ecosystems and remain a core part of local diets, livelihood and culture. New species like salmon and char have been observed, and a surge in populations of predatory fish like northern pike (Esox lucius) is thought to be shifting the balance of predator to prey species. Stocks of lake trout (Salvelinus namaycush) and Rat River Dolly Varden char (Salvelinus malma) have previously shown signs of population decline, and some fishers report catching less burbot (Lota lota) than in the past. However, more recent studies of lake trout in Great Bear Lake indicate improved stock status. Reports of less healthy and skinnier fish with “softer” flesh and irregularities like sores and lumps have been made. Mercury levels in the tissue of subsistence fish species like Walleye and burbot have been examined and advisories on fish consumption have been issued in some lakes. Communities across the sub-basin have expressed concern for the health and sustainability of fish populations and many have adapted their fishing practices. Some Sahtu and Dehcho communities consume less fish than in the past due to concerns for elevated mercury levels, and the Gwich’in use a larger net mesh to reduce catching smaller fish and assist in ongoing efforts to restore char populations. Although this assessment includes scientific data for some fish species, limited data was found for Arctic fish stocks. Indigenous Knowledge and scientific observations of changes in wetlands and riparian forests in the sub-basin were not found.
The following table summarizes the availability of information for each Habitat and Species indicator.
Indigenous Knowledge Information and Data
Indigenous Knowledge Availability in Public Sources1
Science Information and Data2
Science Data Availability2
Oral histories and local observations of fish abundance, timing and distribution, species diversity and fish health condition.
Many observations from several locations.
Fish (including salmon, suckers, pickerels, burbot) abundance, timing and distribution, species diversity and fish health condition/
Lack of data on fish stocks.
Oral histories and stories of wetland and forest (and other habitat / land use)
Limited observations from few locations
Number, location and total area of wetlands. Species diversity in wetlands where available.
2020 Canadian Wetland Inventory was published but still requires ground validation.
Local observations and oral histories of riparian forests
No information found.
Number, location, total area of riparian forests areas. Species diversity of riparian forests where available.
No data found
1 Qualifiers for the availability of local and Indigenous Knowledge observations in publicly available sources: Limited = 1-2 observations; Some = 3-4 observations; Many = 5 or more observations
2 Qualifiers for the availability of science data in publicly available sources: Low = Individual studies or locations; Many = Network of monitoring stations across the basin
Changes in fish populations and health condition have been observed in the Mackenzie Great Bear sub-basin.
Wetlands & Riparian Forests
Current wetland mapping is available but information on changes over time in wetlands in the Mackenzie Great Bear sub-basin is limited. Indigenous communities have observed changes in wetland-dependent wildlife populations.
Some observations of population changes of wetland-dependent animal species, like beaver, have been recorded. For example, an increase in beaver activity has raised concern among the Inuvialuit. Inuvialuit community members have observed how an increase in beaver dams and lodges along key waterways leads to lower water levels and disrupts travel and access to fishing areas, and in some cases, the dams prevent fish passage into preferred fishing locations. Conversely, Gwich’in elders have observed that increased beaver activity is not disrupting char movement or habitat on the Rat River, but question why beaver activity is increasing. Additional information on local observations of changes in wetlands was not found.
Wetlands are a major component of the landscape in the Mackenzie Great Bear sub-basin, with percent coverage varying from 25% to more than 50%, depending on the ecoregion. The Mackenzie River Delta located in the north of the sub-basin is the second largest wetland in Canada and supports a diverse array of wildlife, fish and birds. Limited information was found on the changes in the total number and location of wetland areas and species diversity. A Canadian Wetland inventory completed recently indicates more wetland cover than that estimated by land cover mapping cited above, especially in the Plains around Mackenzie River and west of Great Bear Lake, but this inventory is still under development and requires field-validation.
Health & Wellbeing