Influence of Kokanee Salmon and Man on the Water Quality of Lower McDonald Creek, Glacier National Park, Montana

摘要

Kokanee salmon (Oncorhynchus nerka) spawn each fall in lower McDonald Creek near the western boundary of Glacier National Park, northwestern Montana. This study was designed to: (1) determine the impact of salmon decomposition upon selected hydrochemical patterns in McDonald Creek; and (2) evaluate the impacts of a sewage spray-field treatment facility and horse pasture upon selected chemical and bacteriological patterns of the creek. Streamflow and water quality relationships above Lake McDonald differed considerably from those in the spawning reach of the creek below the lake. There were no detectable increases in major ion concentrations during the 1979-1980 sampling period attributable to salmon decomposition. Nitrate-nitrogen concentrations did not increase below the salmon spawning area; however, total phosphorus exhibited a three-fold increase in concentration coincident with initial carcass decomposition in late October 1980.