This project is proposed as on-site, partial mitigation for impacts of Albeni Falls Dam.  The goal of this project is to recover the Lake Pend Oreille fishery that was negatively impacted following construction and operation of Albeni Falls Dam. Historically, Lake Pend Oreille was the most popular fishery in Idaho, supporting both a high yield kokanee fishery and a trophy fishery for bull trout and rainbow trout. Recovery efforts focus on kokanee because they are an important sport fish and the primary prey for native bull trout (ESA listed) and rainbow trout.

Starting in the mid-1960s, the kokanee population rapidly declined in response to consistent full draw downs of the lake that reduced the quantity and quality of shoreline spawning habitat. Since 1996, winter lake level manipulations designed to improve kokanee spawning success have been implemented and evaluated. The effects of this strategy are currently unclear and are still being examined.  Partly, this strategy still has not been tested to the extent necessary because the kokanee population was at low density during the study period. The benefit to kokanee from a higher winter lake level is expected be greater as spawner density increases; however, increased predation from a rapid expansion of the lake trout population became the primary limiting factor for kokanee shortly after lake level manipulations were instituted and kept the population at low density. In response, an aggressive predator removal program was initiated in 2006 to suppress lake trout over the long-term and rainbow trout over the short-term. This program has demonstrated remarkable success, with the lake trout population now in steep decline and the kokanee population steadily rebounding in response to reduced predation.  Kokanee have sufficiently rebounded to allow a limited harvest fishery in 2013 for the first time since 1999.

We propose continued work to evaluate winter lake level management and an upward trending kokanee population should allow this strategy to be more adequately evaluated.  We will examine new approaches to assess effectiveness, including mixed modeling using existing data and more direct methods (e.g., in situ egg incubation) for evaluating the effects of winter lake levels. The egg incubation will involve burying eggs in shoreline substrates to determine incubation success under various habitat conditions. We will conduct a midwater trawl capture efficiency study to improve on traditional kokanee population monitoring techniques. Recognizing the constraints that a high winter lake level to benefit kokanee often puts on the hydrosystem, we also propose new research to evaluate the addition of spawning gravels at depths below the minimum pool elevation. While this approach may not be able to provide habitat at the scale necessary to replace the need for higher winter lake levels in years of high kokanee density, we want to evaluate whether it has potential to increase the threshold spawner density at which a higher winter elevation is needed. In practice, this would allow a higher winter lake level to be requested less frequently.  During this contract period, sites will be investigated to conduct gravel addition in future years.

Continued activities associated with predator reduction are also planned. Work during past years was productive and suggested predation can sufficiently be reduced to allow kokanee recovery. If recent trends continue, we anticipate that our objective of reducing the lake trout population to pre-1999 adult abundance (1,800 fish) to reduce negative interactions with bull trout and reduce predation on kokanee will be met in the near future. Afterwards, we expect reduced effort will be needed to maintain a suppressed lake trout population.

Given the progress toward evaluating and addressing the primary limiting factors (spawning habitat, predation) for kokanee, we will continue research to evaluate other potential limiting factors that could play an increasing role as kokanee density increases. We will evaluate the effects that zooplankton and mysid distribution have on kokanee survival, especially with respect to altering hatchery stocking practices to improve kokanee survival. Additionally, we will investigate limnological conditions and how they may have changed over time.  Overall, we are taking a more holistic research approach to increase our ability to meet project objectives. Further, this will allow us to identify any flexibility that might exist to meet these objectives using new or alternative management actions (e.g, spawning gravel addition).

Much of the proposed work will be accomplished by Idaho Fish and Game staff. In addition, we will fund graduate studies through the University of Idaho and issue subcontracts for other activities, such as lake trout removal netting, substrate mapping and evaluation, and examination of kokanee otoliths for thermal marks. While BPA funding for this proposal will be used to accomplish proposed activities, Avista Utilities provides a large cost share that allows for funding of the Angler Incentive Program, lake trout removal netting, bull trout monitoring, and other items that are closely tied to this project.

In combination, the proposed project activities address limiting factors for kokanee and will allow for progress toward the objectives of kokanee recovery, bull trout and westslope cutthroat trout preservation, and restoration of a trophy fishery for bull trout and rainbow trout. These objectives are consistent with reasonable and prudent measures in the 2000 FCRPS USFWS Biological Opinion for bull trout and with the USFWS Draft Bull Trout Recovery Plan. Similarly, they are aligned with objectives in the Council’s 2009 Fish and Wildlife Program, the Pend Oreille Subbasin Plan, and the Idaho Fish and Game 2007-2012 Fisheries Management Plan.

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

Objective 1-  Kokanee restoration, "Restore the kokanee population to a level that supports a sustainable annual harvest of 300,000 kokanee."

Objective 2 - Bull trout / Cutthroat trout Conservation,  "Reduce the lake trout population to pre-1999 abundance (about 1,800) for fish over 406 mm to minimize predation and competition risks to bull trout and westslope cutthroat trout."

Objective 3-  Restore the Trophy Fishery for Bull Trout and Rainbow Trout,  "Restore the bull trout population to meet USFWS recovery criteria and provide a sustainable annual harvest of 1,000 fish. And, restore a trophy rainbow trout fishery that provides sustained annual catch rates of 30 hr/fish, with an annual harvest of 3,000 fish >24 inches and 3% (90 fish) over 20 pounds."