Conservation Potential of Fish Passage Barriers for Native Fish in the Narraway and Muskeg River Watersheds
Scott Seward and Jason Blackburn
To effectively safeguard against extirpation of native fish species in Alberta, it is essential to protect native populations from hybridization and competition with invasive species. In Alberta, several subpopulations of native fish remain protected from invasive species primarily because of waterfalls that impede upstream fish movement. Maintaining and isolating these subpopulations from invasion, in balance with the extirpation risks associated with isolation, is critical to the protection and persistence of native fish. Cataloguing waterfalls is a necessary first step in determining where invasion can be managed. We used Google Earth, Bing Maps, and aerial reconnaissance to identify 110 potential fish barrier locations in the Narraway River watershed and 14 in the Muskeg River watershed in 2019. We completed barrier assessments in the Narraway watershed in high flow conditions in 2019. Low flow assessments were cancelled in 2019 due to unseasonably high water conditions and again in 2020 due to COVID-19.
In 2021, Alberta Conservation Association staff ground-truthed 99 potential barriers and completed full field assessments at 20 potential barriers in the Narraway watershed. We identified three tributaries (Dinosaur, Stetson, and Sulphur creeks) with absolute barriers to fish passage and one tributary (Stinking Creek) with an effective barrier to fish passage. We ground-truthed all 14 potential barriers and completed full assessments at two of the 14 potential barriers in the Muskeg watershed. We identified one absolute barrier to fish passage along the mainstem of the Muskeg River. Knowing the locations of key barriers to fish passage in the Narraway and Muskeg river watersheds will aid in the management of invasive species encroachment in these Alberta watersheds.