Lakes in Region 2 are surveyed to provide information essential for effective management. The surveys are accomplished on lakes ranging in size from a few acres, such as Harper's Lake and Beavertail Pond, to lakes as large as Georgetown Lake, which is several thousand acres in size. Gill netting of these lakes provides managers with information on species composition and average size, size ranges and condition factors of important fish species. Fish are inspected for symptoms of disease, injuries and the potential presence of parasites. Individually numbered tags are inserted in many important sport fish. Retrieval of these tagged fish in subsequent surveys or by anglers provides managers with critical information on fish harvest rates, growth rates and movements.
In the Clearwater River drainage an unwanted illegal introduction of northern pike occurred in the late 1980's or early 1990's. By the mid 1990's northern pike population expansion in the drainage began to have serious negative impacts on the fishery, severely reducing densities of other desirable sport fish species such as kokanee, westslope cutthroat, brown and bull trout, largemouth bass, and yellow perch. Impacts on bull trout are of particular concern since they are listed as an endangered species. Lakes impacted by this introduction include Inez, Seeley, and Salmon. These lakes account for 52 percent of the lake surface area in the Clearwater drainage. In response to this introduction, FWP implemented liberal fishing regulations to encourage harvest of northern pike. We are attempting to maintain a diverse fishery in the impacted lakes by encouraging removal of pike by anglers along with low-density hatchery supplementation of kokanee and westslope cutthroat trout. Monitoring of these lakes by gill netting and angler contacts provides information on effectiveness of our management strategies.
For many years fish population trends on Georgetown Lake were monitored by angler creel surveys without any netting or direct population surveys by biologists. A few years ago, FWP began to have some concerns about the blue ribbon fishery of Georgetown Lake. The renowned trophy brook trout population in Georgetown Lake was in severe decline and kokanee were also decreasing in numbers. In addition, FWP received several reports of an unwanted northern pike introduction in Georgetown Lake. For these reasons, FWP decided to propose conducting a gill netting survey of Georgetown Lake. Without good baseline data we felt effective management decisions could not be made.
This decision was met with some opposition by the angling public. Some didn't see the need for the surveys at all. Others expressed fears of too many fish being killed during the surveys. Meetings by managers with concerned lakeside homeowners and sportsmen's groups began to alleviate concerns and limited gill netting surveys were initiated in 2004. Surveys that year revealed northern pike were not present in Georgetown Lake and a baseline was established for relative densities and size compositions of desirable species including kokanee, rainbow and brook trout. Our survey that year removed less than one-tenth of one percent of the fish, which are stocked annually by FWP in Georgetown Lake. Based upon this low impact and the perceived usefulness of the information, anglers and homeowners encouraged FWP to conduct additional surveys in future years. Subsequent surveys have provided information on recovery of the brook trout population, which is being aided by FWP hatchery supplementation. Surveys indicate kokanee populations have stabilized and average size of kokanee is now significantly better than historic averages. Public support of our management strategies is greatly appreciated by FWP.
Streamside setbacks are important to protecting fish and wildlife habitat. In the Bitterroot Valley, there has been an effort to delineate buffer zones and setbacks for structures along the Bitterroot River and tributaries. Development too close to streams impacts fish and wildlife habitat and well as water quality. Some homes are close enough that stream processes have caused property damage. The effort has not been without controversy, but hopefully setbacks and buffer zones will be delineated to give some measure of protection for wildlife and fish habitat along streams.
Fishing in the Bitterroot River was good this year, although low stream flows late in the summer made floating on some sections difficult. Whirling disease appears to be the cause of declines in rainbow trout populations in the East Fork of the Bitterroot River. At this time, the populations of trout in the West Fork and main Bitterroot River are stable. The populations of cutthroat and bull trout on Bitterroot National Forest streams seems to be stable. These streams are excellent places to fish, particularly for young anglers. The fish are almost always biting and eager to reward a reasonably presented fly, lure or bait.
The Clearwater Drainage is the largest tributary within the Blackfoot River watershed. This is a unique system with many high quality trout streams interspersed with a series of lakes along the main stem. Prior to 2005, little was known about the streams and fish populations outside the 8 major lakes. Last year, FWP began a series of studies examining fish species composition and distribution through the tributary network, a bull trout telemetry project aimed at identifying problems associated with the decline of these fish and a fisheries graduate project evaluating the impacts of several major dams along the main stem. Results of these projects will help direct future fisheries management within the watershed and form one basis for ongoing land use planning that emphasizes habitat protection.
Preliminary results indicate that the Clearwater Drainage remains a stronghold for native trout species, but rapid human population growth and development, as well as continued illegal fish introductions (including northern pike, brook stickleback, and central mudminnow) pose additional threats. Initial bull trout telemetry work affirmed and emphasized the importance of Morrell Creek as a migratory bull trout spawning tributary. This stream, along with the main stem Clearwater River, act as critical habitats and migration corridors for lake-dwelling bull trout populations in the lower drainage. Work beginning in 2007 will focus on populations in the upper Clearwater watershed.
Milltown Dam was built in 1907 at the confluence of the Blackfoot and Clark Fork rivers in western Montana, and is a unique part of Montana history. The hydroelectric dam was built to power a mill in Bonner that cut timber for mines in Butte and for smelting operations in Anaconda. Over the last century, sediments laden with heavy metals from hard rock mining upstream in the Clark Fork drainage have accumulated in the reservoir impounded by Milltown Dam. These sediments threaten human health, and have serious consequences for fish health. Aquatic organisms, including fish, are severely affected by the metals in the water (in particular, copper). However, it is not just sediments in the reservoir or in the Clark Fork River that threaten many fish- the dam itself and the reservoir have affected fish in the area. Milltown Dam will be removed in the next few years and the watershed will once again regain connectivity, but before that happens, we will be monitoring the effects of removing the dam on fish health and survival.
Historically, fish native to the Clark Fork watershed like bull trout and westslope cutthroat trout used large, connected, ecologically and geographically distinct habitats spanning hundreds of miles to express different stages of their life histories. The dam has not allowed upstream fish passage, has limited downstream fish movements and created a reservoir that has fostered a population of exotic northern pike. Recent studies show the dam’s continued affect on an enormous geographic scale. Milltown Dam annually impedes migrations of tens of thousands of fish, and data suggest that fish that migrate to the dam do not spawn once their migration is impeded, and many die.
In the spring 2006 initial work began toward removing Milltown Dam and the contaminated sediments that have accumulated behind the dam in the reservoir. This is a big project, in cost, scale, and it is really big for the benefits it will provide to fish and wildlife in the area. However, with any big project in the river, the removal activities could have deleterious consequences for fish in the area through sediment releases. This study will closely follow the health, condition and mortality of fish downstream of the dam and compare these trends to fish in other rivers (up and downstream from the dam). By using data at all these locations, we will be able to tell what type of effect the dam removal activities are having. This monitoring will take into account results from caged fish studies targeting the condition of juvenile trout, radio telemetry to asses the movements and mortality of adult wild fish, and fish population monitoring that will tell us how all the changes translate into changes in different reaches of river with different species and ages of fish.
In 2006, the first stage of the dam removal process saw the elimination of the reservoir because of a drawdown. However, this drawdown lead to mortality of caged fish and free roaming wild adult fish implanted with radio transmitters. The cause of the mortality was likely the result of the cumulative effects of several stresses brought on by the drawdown and sediment that was scoured from the reservoir. Although this was a setback, and stopped the drawdown of the reservoir for several months, it is unclear what effect the mortalities we documented had on fish populations in the area. In spring 2007, our monitoring work will help answer these questions.
The story of the Blackfoot River continues as one of restoration and renewal, thanks to the hard work of river conservationists. At the very headwaters of the Blackfoot River, is the proposed clean-up of the toxic Mike Horse Mine tailing dam. During a rainstorm in 1975, the dam partially breached, contaminated the upper River and caused the collapse of the local cutthroat trout population. Although clean up has yet to begin, momentum is building at the local, state and federal levels. At the lower end of the basin is Milltown dam located at the junction of the Blackfoot and Clark Fork Rivers. This run-of-the-river dam has prevented the upstream movement of Blackfoot River fish for 100 years. The early phases of Milltown dam removal are proceeding with the drawdown of the reservoir and the renaturalization of the confluence area now underway.
During 2006, trout populations in the lower Blackfoot River (below the Clearwater River) have held up well despite seven-years of continued drought, with densities (fish> 6.0”) ranging from 800-900 per mile. The lower Blackfoot River supports a low infection of whirling disease and a higher number of suitable spawning streams. Unfortunately, this is not the case in the Blackfoot River upstream of the Clearwater where densities of fish have declined 30-50% compared to the pre-drought period. Densities are as low as 60-70/mile in some reaches of the middle Blackfoot River near Nevada Creek. With these low densities as a barometer of river health, habitat work is also continuing throughout the tributaries of the middle and upper the Blackfoot River. This restoration endeavor involves conservation groups and agencies working with willing landowners. With 80 - 90% of tributaries identified as fisheries-impaired, there is plenty of restoration work ahead.
