This project is proposed as on-site, partial mitigation for impacts of Albeni Falls Dam.  Fall draw downs of the naturally created Lake Pend Oreille greatly reduced the amount of shoreline spawning habitat for kokanee, the primary forage of bull trout and rainbow trout.    Albeni Falls Dam also inundated about 26 miles of the Pend Oreille River and the lower 2 miles of the Clark Fork River.  Thus, both river and lake habitats have been changed by the operation of the dam.  The goal of this project is to recover the sport fisheries that were impacted by the federal hydropower system.
This study has documented that the predation on kokanee is a threat to the Lake Pend Oreille ecosystem.  Exceptionally high predation levels by lake trout and rainbow trout could extirpate kokanee from the lake.  Without kokanee, lake trout and bull trout would be in direct competition for a limited food supply.  In Flathead Lake, Montana and Priest Lake, Idaho, lake trout replaced bull trout once the kokanee forage base was gone.  We therefore propose the objective of restoring the bull trout population so that it is healthy enough to provide a harvest of 1,000 fish annually in the lake.  To accomplish this objective we propose several tasks including the direct removal of lake trout using trap nets and gillnets, and examining the fall draw down of the lake to see if it can be used to reduce the survival of lake trout eggs. Hansen et al. (2006) estimated that lake trout are currently being exploited high enough that annual mortality has exceeded 50% in 2005.  This is beyond the threshold where lake trout populations begin to decline.  Continuing the removal is need to cause a substantial decline in lake trout abundance and increase kokanee abundance.    Rainbow trout are the second most abundant kokanee predator.  Management actions have been enacted to reduce rainbow trout abundance including: allowing unlimited angler harvest, opening tributary streams to fishing, paying anglers to turn in fish heads, and allowing the use of four fishing rods.   The Avista Power Company is cost-sharing on efforts to reduce predation by funding the  bounty program for lake and rainbow trout, and funding a large part of the netting efforts. Part of the current study is to evaluate the effectiveness of the predator reduction efforts on the kokanee population.
We further propose to evaluate the stocking of hatchery kokanee into the lake.  The Cabinet Gorge Fish Hatchery, which annually stocks the lake, is the largest kokanee hatchery in the world and was built with funds from the US Army Corps of Engineers and Avista Power Company.  The hatchery stocks up to 18 million fry at a length of 50 mm, and yet the kokanee population has not recovered.  We propose to continue to mark the otoliths of all hatchery-produced kokanee, monitor their early survival rates, and examine predation on these small fish.     This study will be a graduate project through the University of Idaho.
Field work in this proposal is to be conducted by the Idaho Department of Fish and Game.  A subcontract is proposed with the Washington Department of Fisheries to examine kokanee otoliths collected in 2007, to determine if they are of wild origin. A subcontract is also proposed for commercial fishermen to operate trap nets and gillnets for lake trout removal.

               Tasks in this Statement of Work fall under four major objectives:

Objective 1-  Kokanee restoration, "To restore kokanee abundance in Lake Pend Oreille so that it is capable of sustaining a harvest of 300,000 kokanee on an annual basis, by 2015."  Several work elements address this objective.  One work element is to assist the USFWS with long-term lake level management planning.  Fluctuating the winter water level has been shown to increase spawning habitat for kokanee and increase their egg-to-fry survival by 2.5 times.  We will continue to provide input into the process of choosing winter lake levels throughout the duration of this project.  The project will also monitor shoreline spawning habitat to see if lake level management is producing the desired habitat.  Predator control, explained in the objective below, is also intended to help restore kokanee.    During the project, the kokanee population will be examined to determine if these predator control efforts are successful.  A new task for 2008 is to evaluate the benefits of fertilization to enhance the kokanee population.  Studies will begin that define the needed baseline data as well as determine the methods to accomplish this approach.

Objective 2 - Bull trout / Cutthroat trout Preservation,  "To reduce the lake trout population to a level where lake trout are no longer threatening the kokanee population by 2010.   Work elements of  "Lake trout removal by trap nets and gillnets" and  "Lake level manipulation to impact lake trout spawning",  both are to reduce the number of lake trout, which are known to be a competitor of bull trout and a predator on cutthroat trout.  Researchers are also evaluating whether or not lake levels can be manipulated to impact lake trout spawning. The lake trout are at an all time high and their predation on kokanee threatens to collapse the stock.  This work element is to try to reduce their abundance by de-watering their eggs after spawning, if feasible.  The project is also attempting to remove lake trout to reduce predation on kokanee so that kokanee can recover.

Objective 3-  Restore Bull Trout,  "To restore bull trout so that they can meet USFWS recovery criteria and provide a fishery with a harvest of 1,000 fish annually in Lake Pend Oreille by 2030".  This is relates to object 2.  Efforts to reduce predators will also help bull trout since kokanee are the main food supply for bull trout as well.  The work element to "Estimate rainbow trout using up-looking hydroacoustics" is to develop a method to determine rainbow trout abundance to see if the current reduction efforts are successful.  As part of a cooperative effort, Avista Power Company is funding a $15/fish bounty program on rainbow and lake trout to help reduce predator numbers.  The work element to  "Evaluate predator reduction program", will document if the kokanee population is responding to recovery efforts.

Objective 4-  Improve stocking program for kokanee,  "Improve the stocking program for kokanee in Lake Pend Oreille so that it contributes 375,000 kokanee to the harvest annually (the original mitigation objective for the hatchery), without having hatchery kokanee replace the wild stock within the lake".  This work element is to examine the early life history of hatchery kokanee to determine the major sources of mortality. Currently about 70% of all hatchery fry die within 3 months of being stocked into the lake.  Recommendation for improving the hatchery stock will be made once the problems are determined.