Editor’s note: This blog was written by ICL’s summer intern in Boise, Mackenzie Case.
Recently as part of our Adventure Series, Idaho Conservation League staff and volunteers participated in the U.S. Forest Service’s rangewide bull trout eDNA study. Over two days, we took samples from over 20 sites along the Middle Fork Weiser River in the Payette National Forest. Although some of the sites were tough to access, the effort was certainly worth it!
These samples could indicate whether bull trout are present in the river by detecting DNA. Not only did ICL and our volunteers have a chance to enjoy beautiful scenery, but our work will also provide the Forest Service important data on these fish and their habitat. The resulting data could also help shape conservation and restoration efforts.
Healthy Fish Need Healthy Streams
Bull trout are native to the Northwest and protected as a threatened species under the Endangered Species Act. According to the U.S. Fish and Wildlife Service, the once abundant coldwater fish only occupy 21% of their historic range. Bull trout require cold, clear streams to survive and are threatened by habitat degradation, nonnative fish species and climate change. Since these fish rely on healthy streams to thrive, their presence is also indicative of a healthy ecosystem for other wildlife and overall water quality. In Idaho, about 9,000 miles of streams are designated critical habitat for bull trout.
Why Do We Need More Info?
Although we know that bull trout and their habitat are declining, scientists still need more information to effectively implement conservation efforts. For their rangewide bull trout eDNA project, the Forest Service produced models to predict which streams have a high probability of having bull trout. Environmental DNA (eDNA) sampling easily and quickly confirms the presence of fish without needing a single fish being spotted. eDNA sampling doesn’t just work for bull trout. It can also be used to detect other fish species and rare aquatic species such as amphibians.
Unfortunately, resources are limited. To collect valuable data, the Forest Service recruits and relies on dedicated volunteers to sample sites with a more than 25% probability of having bull trout. Over 20 organizations-including ICL-support this three-year project. By 2018, the project aims to produce a comprehensive assessment of bull trout populations across the Northwest.
We sent our samples off to the Forest Service for analysis. Within the next few months, we’ll find out whether bull trout are indeed present in the Middle Fork Weiser River. We’ll keep you posted. Also, keep an eye out for more opportunities like this through our ICL Adventure Series!
– Mackenzie Case