Effects of selenium and other surface coal mine influences on fish and invertebrates in Canadian Rockies streams

Physical and chemical influences downstream of surface coal mines, including selenium (Se) release, water quality shifts, and habitat alterations can affect aquatic organisms. To evaluate these influences at the community level of organization, fish and macroinvertebrates were studied in mine-affected and reference streams. Se can be toxic to aquatic organisms and was measured in lotic food chains (water, biofilm, macroinvertebrates and juvenile salmonids). Invertebrate Se was significantly related to Se in juvenile fish muscle (westslope cutthroat, bull, rainbow and brook trout) and Se concentrations exceeded proposed individual-level reproductive effects thresholds in some rainbow and cutthroat trout. Community-level effects were only detected in rainbow trout where species specific biomass was negatively related to muscle Se concentration in stream reaches. Macroinvertebrate assemblages varied along a mineinfluence gradient defined by Se, alkalinity, substrate embeddedness and interstitial material size. Ephemeroptera were the most sensitive to mining effects and potential mechanisms influencing community composition included Se and ion toxicity and habitat degradation. This project highlights the need to study multiple organisms at different levels of ecological organization in order to understand and manage diverse mining impacts.

xi, 108 leaves : col. maps ; 29 cm