Status and Distribution of the Northern River Otter (Lontra canadensis) in the Upper Clark Fork River Basin

The State of Montana assessed injuries to natural resources resulting from the actions of ARCO and its predecessors in the 1980s and 1990s. In the final report summarizing injuries, the Northern river otter (Lontra canadensis) was identified as one species greatly impacted by habitat degradation. Recent research by Montana Fish, Wildlife & Parks and MFWP trapping records demonstrate that otters have begun to return to the UCFRB, but this population appears markedly less robust than those in other drainages in north - and southwestern Montana. Working cooperatively with MFWP, we are conducting a detailed study documenting the status and distribution of otters in the UCFRB. Surveys of the Clark Fork river drainage from Silver Bow Creek to the Warm Springs Ponds and downriver to Bonner including main tributaries are being conducted. Otter and beaver sign are being catalogued, DNA analyses of otter hair and fecal samples are being performed to identify individuals, and an assessment of current habitat conditions necessary to support otters is being made. Preliminary results from the summer of 2009 catalogued 13 latrine sites and 6 possible den sites along the Clark Fork River. Forty-nine scats were collected from which a subsample will be analyzed for DNA. Fifty-eight beaver lodges and 8 dams were observed along the Clark Fork River proper, 6 lodges were observed along the Little Blackfoot River and abundant evidence of beaver activity was observed when walking Silver Bow Creek. This research will continue through 2011