Project 200724600 was initiated in 2007 in response to recommendations of Geist et al. (2004) and Scholz et al. (2005a). Albeni Falls Dam interferes with natural migration of adfluvial Bull Trout in the Lake Pend Oreille/Pend Oreille River system and has contributed to the extirpation of populations originating downstream of the dam. Genetically isolated populations originating upstream routinely pass the dam on their own volition or through entrainment and cannot return to natal tributaries to spawn or access thermal refuge and forage in Lake Pend Oreille. Mortality rates of migratory Bull Trout and Westslope Cutthroat Trout blocked from passing Albeni Falls Dam are extremely high due to summer water temperatures exceeding 24 °C. Reconnecting the fragmented Pend Oreille/Clark Fork system is thought to be the best way to restore local Bull Trout populations and has been required at 5 out of 6 existing mainstem dams in the U.S. through FERC license negotiations. Albeni Falls Dam is the only Federally owned and operated dam in the system and the USACE was required by the U.S. Fish and Wildlife Service to study the feasibility of restoring passage by October 1, 2004. Albeni Falls Dam upstream fish passage is the single most important conservation action that can be undertaken to recover and conserve native migratory salmonids to the lower Pend Oreille watershed.

The goals of this project are to: 1) provide temporary upstream passage for Bull Trout at Albeni Falls Dam; 2) investigate long-term fish passage solutions at Albeni Falls Dam; and 3) fill data gaps identified through this and related projects on Bull Trout and Westslope Cutthroat Trout associated with mainstem habitat connectivity in the Pend Oreille/ Clark Fork system. Our focuses since the last categorical review in 2012 were:

•Improving safe and timely passage at AFD with a temporary upstream trap.

•Studying the feasibility of improving the attractiveness of fish trap and ladder entrances with the introduction of: 1) natal stream water; 2) conspecific pheromones; and 3) cold water.

•Collaborating with the Corps and Bonneville Power Administration (BPA) to finalize studies related to the feasibility of restoring passage for subadult and adult Bull Trout at AFD.

Trapping at the dam was discontinued in 2020, as no fish had been collected. Tests of attractants such as pheromones, natal stream water, and cold water temperatures were successful at attracting Bull Trout in a laboratory setting, however, field trials failed to improve trap effectiveness. The project transitioned to the management strategy of capturing Bull Trout only by boat electrofishing and transporting them above the dam with minimal tagging effort during 2021-2023. We have continued to collaborate with USACE on permanent fish passage design and implementation which will continue during this performance period.

Throughout the historic range of Westslope Cutthroat Trout, few of the remaining stocks have been genetically classified on the basis of chromosome counts, biochemical characteristics, or molecular genetic information (USFWS 2000).  Although Westslope Cutthroat Trout stocks with varying degrees of genetic purity are known to occur across the subspecies' range, there is currently little definitive information on the genetic characteristics of most stocks (U.S. Fish and Wildlife Service 1999).  The genetic cataloging portion of this project will investigate the genetic characteristics and degree of genetic purity of Westslope Cutthroat Trout in the upper Pend Oreille Subbasin and provide a means to identify fish of unknown origin to a most-probable region and natal tributary.  These results will greatly improve the probability of Westslope Cutthroat Trout passage at Albeni Falls Dam in the future.

Although our previous work has focused on Bull Trout and Westslope Cutthroat Trout, other native salmonids may also be negatively affected by dams that were constructed without fish passage facilities. Among those species, Mountain Whitefish (Prosopium williamsoni) may be of particular concern as anecdotal reports suggest that their numbers may be declining both within the LPO/PR system and across much of their native range. In 2018-19 KNRD and EWU crews captured a total of 255 (2018 (n=155), 2019 (n=100)) Mountain Whitefish below AFD, in more recent years 2020-2024 (2020 (n=20), 2021(n=28), 2022 (n=21), 2023 (n=11), 2024(n=27)) both crews have captured 107. Showing a steady decline in numbers. KRND and EWU plan on a preliminary evaluation of Mountain Whitefish in the Priest and Pend Oreille River.

We will compile data from the primary literature, the gray literature, and from direct conversations with personnel from all agencies that might be documenting the status of Mountain Whitefish populations. To date, genetic and ecological studies on Mountain Whitefish have been limited (Dunham et al. 2022). Our initial summary of the available data will allow us to better determine the need for future studies focused on the genetic and ecological status of this species.