Since the last ice age, bull trout (Salvelinus confluentus) have survived in the cold, clear waters of the northwest. Habitat degradation, dams, invasive species, warming waters and overharvest have significantly reduced their numbers and range in the last century. Even after being listed as a threatened species in 1998, the current range of bull trout is surprisingly not well known. We know the present distribution in major systems such as the Middle Fork, South Fork and North Fork of the Flathead. But many smaller streams remain undocumented. Having a clear picture of where bull trout continue to survive will help ensure all currently occupied bull trout habitat is protected and managed to help recover the species.
To those ends, the US Forest Service Rocky Mountain Research Station is using an emerging technology known as environmental DNA (eDNA) to determine the presence or absence of a species in aquatic systems that is more sensitive for detecting target organisms and faster and less expensive than previous methods. eDNA is simply the technique of collecting water samples, filtering out microscopic bits of DNA shed by organisms in the waterbody, and checking to see if your target organism’s genetic material is present. This technology is being used in Montana to sample for the presence of invasive zebra and quagga mussels in Tiber and Canyon Ferry reservoirs.
The goal of the Forest Service effort is to complete a range-wide inventory of bull trout using a crowd-based approach. By engaging volunteers from a wide range of organizations, including the Flathead Valley TU chapter, the Forest Service is able to greatly expand its effort to document bull trout. Our chapter has long been involved in bull trout conservation and restoration. We created a public service announcement to increase awareness of bull trout fishing regulations and proper catch and release techniques with the slogan “Every Bull Trout Counts”. We are heavily engaged with lake trout suppression efforts in Swan and Flathead Lakes, and we continue to review Montana FWP bull trout redd counts every year.
Volunteering to see if there are undocumented streams with bull trout populations in the Flathead was a natural fit for our chapter. We reviewed Forest Service maps identifying streams to inventory and decided to focus on the Upper Stillwater and Whitefish Rivers. The Forest Service provided sterile sampling equipment and instruction. We provided the hardy sampling crew. Using GPS as our guide, we often bushwhacked several hundred yards through the heavily vegetated riparian areas of northwest Montana to access sampling sites spaced roughly one kilometer apart on a stream. Taking samples by pumping 5 liters of stream water through a filter was comparatively easy. We labeled our samples by site and returned them to the Forest Service for testing. This spring we plan to partner with students from the Whitefish Independent High School who have shown an interest in conservation to continue our efforts in an even more remote section of the upper Whitefish River!
If you are interested in learning more about eDNA, the bull trout monitoring effort, or getting involved in this important citizen science project, go to: www.fs.fed.us/rm/boise/AWAE/projects/BullTrout_eDNA.html
Or contact Mike Young at the Forest Science Lab in Missoula at 406-542-3254 or email at email@example.com.
Larry Timchack, Flathead Valley Chapter of Trout Unlimited
Winter 2018 Trout Line