Year Established: 2011 Start Date: 2011-03-01 End Date: 2012-02-28
Total Federal Funds: $1,500 Total Non-Federal Funds: $638
Principal Investigators: Joe Naughton
Abstract: Fish were extirpated from Silver Bow Creek (SBC) near Butte, Montana, following more than a century of contamination from local mining operations and municipal sewage effluent , . Superfund remediation activities focused on the removal of tailings deposits and the treatment of contaminated groundwater have been ongoing in the SBC watershed for more than a decade. Heavy metal concentrations have been drastically reduced in the stream , and now six fish species are present including three in the trout family Salmonidae. Since 2000, trout and sucker (Catostomidae) abundance has steadily increased in portions of SBC . However, despite signs of improvement, synoptic fish samples suggest that current water quality problems are influencing the distribution of the individual fish taxa. Electrofishing surveys conducted in Jul-2010 identified a 13 km stream section below the Butte Wastewater Treatment Plant (treatment plant) effluent where trout were nearly absent (hereafter this stream section referred to as the ‘trout dead zone’). Trout were far more abundant in SBC above the treatment plant and in sampled tributaries (Figure 1) . However, the absence of trout in the trout dead zone may be a seasonal phenomenon. In 2009, large proportions of marked brook trout Salvelinus fontinalis were detected moving from non-contaminated SBC tributaries into the trout dead zone during the winter . Fish abundance patterns in SBC appear to be species specific reflecting differences in species tolerance limits. Longnose sucker Catostomus catostomus abundance patterns were very different from trout abundance patterns in SBC. The primary goal of this research project is to understand the factors responsible for the spatial and temporal variation in fish abundance patterns in the remediated portion of SBC.