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 predator management in order to maintain a robust kokanee population 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. This strategy was believed to be working effectively for a number of years, but recent research showed that a benefit to kokanee recruitment was, in fact, not occurring.  This same research project showed that downwelling currents provide a survival advantage to incubating kokanee eggs.  Using this new information, we plan to test a spawning habitat enhancement strategy.  We mechanically added suitable-sized spawning substrate in a shoreline reach that has downwelling currents present, but currently the area formerly had substrate too large for kokanee to use for spawning.  This will serve as a pilot study to help determine whether or not this approach should be implemented on a larger scale. If successful, this approach, combined with the knowledge that the four foot winter water level strategy has not worked as intended, will provide more flexibility for the hydrosystem.  

In addition to historical impacts to kokanee from water level management, another limiting factor emerged in the late 1990s.  Nonnative lake trout become abundant as a delayed response to mysid shrimp introduction and posed a predation threat to kokanee.  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 sufficiently rebounded to allow a limited harvest fishery in 2013 for the first time since 1999.  The kokanee harvest limit was then raised in 2014 following continued kokanee population growth.  Continued activities associated with predator reduction are planned. Work during past years was productive and suggested predation can sufficiently be reduced to allow kokanee recovery. The lake trout population trend indicates that we have likely reached our objective of reducing the lake trout population to pre-1999 adult abundance (1,800 fish), thus reducing negative interactions with bull trout and predation on kokanee. We are now developing strategies to begin reducing lake trout netting effort with the objective of maintaining a suppressed lake trout population.  Netting efforts in 2016 were slightly scaled-back and further reductions should be possible into the future.

Given the progress toward evaluating and addressing the primary limiting factors (lake trout predation, spawning habitat) for kokanee, we will continue research to evaluate other potential limiting factors that could play an increasing role as kokanee density increases.  A potential new threat is emerging with an increase in walleye abundance as documented through the lake trout removal efforts.  Taking a broader view on predator management and evaluation will be required to maintain the gains achieved to this point.  Additionally, 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. 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 a graduate study through the University of Idaho and issue subcontracts for other activities, such as lake trout removal netting. 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 2013-2018 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."