ScholarWorks at University of Montana

Water quality and physical habitat effects on trout distribution and abundance in Silver Bow Creek

Uncontrolled disposal of mining wastes in the Butte mining districts resulted in extirpation of fishes from Silver Bow Creek throughout the 20^th century. Superfund remediation has been ongoing in the watershed since 1998 and is near completion. Overall, metal concentrations in Silver Bow Creek are reduced from pre-remediation levels however. However, the stream is influenced by municipal sewage, and during midsummer, hypoxia has been observed at night downstream from the wastewater discharge. Despite the water quality problems, six fish species, including three sensitive salmonids, now inhabit Silver Bow Creek. To evaluate the success of remediation in reestablishing salmonid populations, spatially-continuous fish abundance and habitat surveys were conducted in coordination with synoptic water quality measurements throughout 34 stream km during the summer of 2011. An extensive stream portion (≈6 km) had low dissolved oxygen (DO/L), and minimum DO concentrations were