Bull trout in the Columbia River Basin were listed as Threatened by the US Fish and Wildlife Service (USFWS) in 1998 (USFWS 2000).  Bull trout populations are threatened by habitat degradation and fragmentation, past fisheries management practices, poor water quality, and blockage of migratory corridors.  Pend Oreille River and Lake is a core area within the Northeast Washington Recovery Unit of the Columbia Basin bull trout population (USFWS 2002a, 2002b).  Recovery of Pend Oreille bull trout is limited by the fact that dams on the mainstem Pend Oreille River (Albeni Falls and Box Canyon dams) have blocked migration of bull trout between Lake Pend Oreille and spawning/rearing areas (USFWS 2002a, 2002b). Albeni Falls Dam is a federal facility under the responsibility of the action agencies (US Army Corps of Engineers, Bonneville Power Administration, and Bureau of Reclamation).  Albeni Falls Dam created two types of problems for bull trout in the Pend Oreille Basin. First, bull trout from natal tributaries above the dam, that either became entrained or had elected to volitionally pass below the dam, were unable to return to spawn in their natal tributaries. (Source populations could include bull trout spawning in the Priest River, inlet tributaries of Pend Oreille Lake, or tributaries of the Clark Fork River below or above Cabinet Gorge Dam.) Second, adfluvial bull trout that formerly spawned in tributaries below the dam and migrated upstream to a cold water refuge in Lake Pend Oreille, Idaho were no longer able to do so.

The goal of this project is to provide temporary upstream passage for bull trout at Albeni Falls Dam on the Pend Oreille River. We propose to collect bull trout below the dam using boat electrofishing.  Any bull trout captured will be biopsied via hole punch and their DNA sent to the USFWS lab in Abernathy, Washington for rapid analysis within 48 hours. Each DNA sample will be compared to DNA from other bull trout populations in the Priest River drainage, Pend Oreille Lake tributaries, and Clark Fork drainage and an assignment will be made as to its probable region of origin.  Prior to release each fish will be implanted with a combination radio-acoustic transmitter to ascertain if the spawning tributary it selected was the same as its assigned tributary. A system of stationary radio receiving stations and airplane/truck/boat surveys will be used to monitor the movement of the tagged fish. This project provides direct on-the-ground benefits for endangered bull trout in the Pend Oreille Basin because it will allow fish, whose migration corridor has been blocked by a dam without fish passage, to return to their natal streams and contribute their genes (which would otherwise have been lost) to the spawning population.

The Tribe completed design, construction, and installation of a temporary upstream fish trap at Albeni Falls Dam in late 2014. The trap consists of a floating pontoon trap structure affixed to the dam face with mooring collars and mooring poles to allow for fluctuating tailrace water elevations.  The structure has a holding pool, short denil fish ladder, and V-trap. Water is supplied through a 4 cfs submersible vertical turbine pump affixed to the face of the dam. The trap is accessed from the tailrace deck by an access platform and ladders or by boat from the tailrace. The structures are secured in boat restricted zone with chain-link fence. To monitor the effectiveness of the facility, bull trout and surrogate species will be initially radio tagged in the tailrace and downstream and returned downstream. Finescale movements of tagged fish will be monitored with fixed yagi and dipole receiving stations at the dam and trap entrance. Once reservoir temperature exceeds 18 C, all new and recaptured bull trout will be moved upstream of Albeni Falls Dam to continue their migration to Lake Pend Oreille or spawning tributaries.

The Albeni Falls Dam temporary fish trap has not collected any Bull Trout as of February 2017 and options to improve its attraction are being explored. Some options being considered are ladder design and possible replacement with pool-weir or orifice designs, orientation of the trap, and potential addition of fish attractants. In 2016, we conducted behavioral experiments with Brook Trout (Salvelinus fontinalis) as a Salvelinus surrogate for Bull Trout in a Y-maze, to test the feasibility of using the maze to determine if Bull Trout could be attracted into an arm supplied with cold water, home stream odor, or conspecific pheromones. We propose to expand the experiments to include Bull Trout during 2017 and 2018.

The purpose of the proposed investigation is to improve the passage of Bull Trout (Salvelinus confluentus) into entrances of fish ladders on the Pend Oreille and Clark Fork rivers. We will use a two-armed Y-maze to test three null hypotheses: 1) Ho1: There is no difference in preference by fish to arms with warmer and cooler water temperature; 2) Ho2: There is no difference in preference by fish to an arm scented with pheromones from the same population (population specific pheromones) or species (conspecific pheromones), i.e., fish from the same stream or different stream, as the fish being tested versus an arm receiving the same water minus the pheromones; 3) Ho3: There is no difference in fish preference to an arm scented with water from its home stream added to the water source in which the fish being tested are acclimated versus the same water source without the home stream water added. Rejection of the null hypotheses and acceptance of the alternatives would potentially suggest simple ways to improve the attractiveness of ladder or trap entrances to Bull Trout at dams on the Pend Oreille/Clark Fork such as: 1) Supplying water of the preferred temperature to the ladder; 2) Holding fish in the ladder in an attempt to attract other conspecifics into it; 3) Scenting the ladder with water collected from various home streams in an attempt to attract fish from different home streams into it;