Threats

The smallmouth bass has significantly lower genetic variation than migratory salmon, making it more vulnerable to environmental change . Effective population sizes are above what is recommended for short-term conservation measures, but below what is recommended for long-term conservation of an isolated population. Each of the smallmouth bass populations is therefore vulnerable in the long term, particularly to population reductions and introductions . The smallmouth bass is also vulnerable because it is only found in the upper Nams River basin. Negative developments in living conditions in this area, outbreaks of diseases , or disasters such as pollution in large parts of the area, could affect a significant part of the population.

Weir and dam construction by power development has resulted in a significant reduction in river stretches with suitable habitats for small whitefish. Rapid areas have been converted into sill reservoirs with relatively stagnant water , which favors trout over small whitefish. In addition, the water flow in the area has generally been reduced due to hydropower regulations. This has led to a smaller water volume, and probably also increased sedimentation, and thus a deterioration of habitats due to the sealing of cavities. Weir and dam construction, as well as reduced water flow, have probably resulted in a significant reduction in the small whitefish population. Further reduction of suitable habitats, or deterioration of habitats, may lead to further population reductions.