Securing a native trout stronghold in the North Fork Blackfoot River

The North Fork Blackfoot River is one of the most important spawning and rearing streams for migratory bull trout and westslope cutthroat trout in the Blackfoot River watershed. Private landowners, watershed groups and government agencies have worked tirelessly for decades to address limiting factors throughout the lower sections of the river.

Today, all major diversions on the North Fork have fish screens, resulting in full connectivity for migrating trout. Furthermore, many water conservation projects involving private landowners have improved flow conditions in areas that were plagued by low streamflow.

The proposed native trout conservation project will complement the success of restoration work in the lower river by expanding the amount of habitat occupied by native trout in the headwaters. The portion of the basin above North Fork Falls in the Scapegoat Wilderness contains 85 miles of connected streams and lakes, representing a large expanse of cold, clean and complex habitat ideal for native trout species.

In 2006, Montana Fish, Wildlife and Parks initiated fisheries surveys in the area upstream of the falls. Trout were documented in three lakes, as well as some tributaries and mainstem sections of the North Fork and East Fork of the North Fork rivers. Genetic analyses revealed these populations were comprised of hybrid individuals with mixtures of rainbow trout, Yellowstone cutthroat trout and westslope cutthroat trout genetics.

The stocking records revealed fish plants began in 1926, with the initial stocking of Yellowstone cutthroat trout in several lakes and tributaries. Stocking by sportsmen groups, outfitters and FWP continued sporadically throughout the 20th century. We assume the current populations originated from those stocking events because no genetic or anecdotal evidence exists to confirm fish were present above the falls prior to stocking.

Interestingly, trout densities in stream sections above the falls are significantly lower than cutthroat trout densities in similar streams in adjacent backcountry drainages like Monture Creek and Copper Creek. Native cutthroat trout have adapted to cold, complex and dynamic stream systems, whereas non-native hybrid trout populations are poorly suited for this high-elevation environment and are unable to utilize the habitat to full capacity.

Electrofishing data was paired with temperature data and stream characteristics to extrapolate sampling results to predict trout distribution throughout the entire North Fork drainage above the falls. The model estimated trout presence in approximately 45 miles of mainstem river and tributary habitats.

What initially began as backcountry fishery inventories, has developed into an exciting, unique and rewarding opportunity to significantly expand the distribution of two native species of concern within an already important drainage. The cold water in the upper elevations will likely persist into the future, even if future warming renders lower sections of the North Fork unsuitable for cutthroat trout and bull trout. The presence of the impassable falls creates an opportunity to establish a secure stronghold, free from the risk of invasion by non-native trout as future environmental conditions facilitate rainbow, brown and brook trout expansion.

To achieve this, we must first remove the non-native trout, which pose a hybridization risk for existing populations below North Fork Falls, as well as the populations that will become established above the falls during this project. Although chemical removal of non-native species is often controversial due to concerns about consequences for non-target organisms, human health risks and ethical considerations, it is the most pertinent conservation technique for this situation. Fortunately, many similar projects in Montana were completed successfully, such as the South Fork Flathead River and Cherry Creek westslope cutthroat trout conservation projects. These projects overcame lots of skepticism, but ultimately garnered public support when individuals experienced firsthand the conservation success and lack of negative consequences from chemical treatment.

Last September, we ventured on horseback into the East Fork of North Fork drainage to complete a pilot-level rotenone investigation. Our primary objectives were to assess the performance of the piscicide, rotenone, in different stream habitats and water chemistry profiles; to assess the effectiveness of the deactivating agent potassium permanganate; and to ground-truth estimates of fish distribution in select streams. Given the remoteness and logistical challenges of implementing a project of this scale, it is important to have accurate estimates of fish distributions, so we don't expend unnecessary effort in areas where fish are absent.

In front-country rotenone projects, biologists often err on the side of caution and treat all flowing water because they are not limited by access to treatment locations. In the Scapegoat Wilderness, minimizing unnecessary expenditures of personnel and travel resources will facilitate project success and reduce wilderness trammeling.

The bioassay results validated the trout distribution model in some tributaries, but failed to accurately predict trout distribution in other streams. Given the discrepancy between modeled distributions and field observations, we plan to conduct another year of fisheries surveys to refine the model within sections of the drainage that have the highest trout densities, as well as address remaining knowledge gaps to develop a clearly defined treatment implementation plan.

As we move forward with permitting and public scoping efforts, we will evaluate the proposed project actions alongside numerous alternatives to develop an appropriate project implementation plan that achieves our conservation goals while minimizing the effects on wilderness values and wilderness integrity. We still have many tasks to complete and planning to accomplish, but barring extenuating circumstances, full project implementation could occur as early as 2020.

Not only will this project facilitate an enduring westslope cutthroat trout and bull trout stronghold, it will also provide an enhanced backcountry fishing opportunity that anglers seeking solitude and eager westslope cutthroat trout are sure to enjoy!

There will be opportunities for formal public comment during the coming year but please feel free to contact me at any time with questions, concerns, and input related to this project and other projects in the Blackfoot. You may contact me at patrick.uthe@mt.gov or 406-542-5532. I hope to see you on the water this season!