The sponsors are to be commended for undertaking the difficult but necessary task of suppressing non-native species in the Pond Oreille basin. Their success so far, particularly in suppressing brook trout in tributary streams, is encouraging. The ISRP fully support their effort to control brook trout populations and northern pike in Box Canyon reservoir. Despite a serious effort, little success has been demonstrated in suppressing lake trout in Upper Priest Lake. The ISRP does not believe that continuation of this component of the project is justified. In Part: Objective 3, "Maintain stable or reduced lake trout numbers" and Deliverable 3 do not meet scientific criteria. Based on the apparent lack of success of past efforts to decrease lake trout and increase bull trout abundance, and the problems posed by recreational activities to trapping lake trout in the Thorofare, success of future efforts is highly uncertain. Qualification: A report on progress in northern pike suppression in Box Canyon reservoir should be provided to the ISRP for review in three years.

1. Purpose: Significance to Regional Programs, Technical Background, and Objectives

Along with habitat degradation, hydrological modification, and unsustainable harvest, impacts from genetic introgression, competition and predation from non-native fishes is inhibiting efforts to sustain and recover native fish communities throughout the Columbia Basin. The intent of the proposed work is to minimize potential impacts of non-native fishes on native species in the Pend Oreille Basin.

There are three different projects in this proposal: 1) eradicate brook trout in three streams and re-establish westslope cutthroat trout, 2) suppress the northern pike population in Box Canyon Reservoir to benefit native species and game fish, and 3) suppress lake trout populations in Upper Priest Lake in Idaho to benefit bull trout. The need for suppressing brook trout, lake trout, and northern pike is a premise for the success of other management activities and is adequately discussed in the background materials. 

The proposal clearly justifies efforts to recover westslope cutthroat trout in tributaries to the Pend Oreille River by eradicating or suppressing non-native brook trout and restocking the streams with native westslope cutthroat (Objectives 1, 2, and 5). This is a fairly new project that has evolved as tasks were accomplished on Graham Creek to reestablish westslope cutthroat trout. The sponsors apparently have successfully suppressed brook trout in two streams using a piscicide, suggesting that this technique could be effective for brook trout suppression in other streams. Using the Harig and Fausch model seems like a reasonable approach for forecasting potential success of cutthroat reintroductions. The proposal would be improved by inclusion of better maps and captions to locate the study sites.

Objective 1: (Reintroduce westslope cutthroat trout to upper Smalle Creek and Goose Creek) seems reasonable, but tabulated data or a report could have been provided on the efficacy of electrofishing and rotenone for brook trout removal.

Objective 2: (Determine the best method for westslope cutthroat trout translocations) is a key long term objective that will not be reached until 2016 when a parental analysis will be done. However, it will be important to track the results of the egg transplants and the success of other early life history stages.

Objective 3 (Maintain stable or reduced lake trout numbers in Upper Priest Lake) is a long term lake trout control project. IDFG has been gill netting lake trout in Upper Priest Lake since 1998 and in 2009 began trapping in the Thorofare, a body of water connecting Priest Lake and Upper Priest Lake which serves as a pathway for movement of lake trout from Priest Lake to Upper Priest. The sponsors state that in spite of these efforts, the lake trout population in Upper Priest Lake has remained stable. The sponsors argue that bull trout in Upper Priest Lake have shown signs of recovery, but the evidence for this is not convincing as the number of bull trout captured in the lake remains low, probably too low to detect statistically significant trends in bull trout abundance. An added problem is that the Thorofare serves as a pathway for boat traffic between Upper Priest Lake and Priest Lake, thus encumbering the trapping effort. In short, the efforts since 1998 have shown little sign of success, and it is uncertain whether they will be successful in reducing lake trout abundance and increasing bull trout populations in Upper Priest Lake in the future. The ISRP 2007-09 review expressed serious concerns about this project and essentially considered the lake trout suppression project of questionable value.

The project would benefit from direct collaboration with biologists working on the same lake trout problem in Flathead Lake. A recent paper by Syslo et al. (2011) documenting 15 years of lake trout control in Yellowstone Lake demonstrates the complexities of trying to suppress this apex predator.

Objective 4 (Reduce northern pike abundance by 85% in Box Canyon Reservoir). The effort to suppress the northern pike population in Box Canyon Reservoir is justified. Northern pike are voracious predators and are abundant in the reservoir, threatening native species and non-native game fish, and they have the potential to move downstream in the Columbia River, possibly endangering recovery of ESA listed salmon. The sponsors, however, present little evidence of how far northern pike have spread in the Columbia. Pike are present downstream at Boundary Reservoir, but flow fluctuations discourage spawning.

The sponsors are applying a suppression technique for northern pike drawn from an Alaskan study that used gillnets to target spawning populations in shallow water. The sponsors conducted a pilot study and state, “From this pilot study, we conclude that intensively netting northern pike in sloughs and backwaters from ice off through the spring freshet could drastically reduce the abundance of northern pike in Box Canyon Reservoir.” However, the results are from only one year of study. The proposal does not provide information on where the pilot study took place and the location of the sloughs where the proposed work will occur.

The technical background is quite thorough but could have been expanded to include more out of basin references to non-native fish suppression attempts. The information on attempts to control northern pike in California was instructive. Mack et al (2000) point out that control of invasives has to be strategic and tackling one species at a time is usually ineffective. An ecosystem approach is required (see also ISAB food web report) but this project does not demonstrate such an approach. The sponsors are not alone in this regard.

The project is very significant for regional programs. There is much overlap with other projects, but there is no apparent direct collaboration or synergy between fish suppression attempts in this project and others, for example, lake trout in Flathead Lake. The proposed work is consistent with several regional native fish recovery plans including the Pend Oreille Subbasin Plan, the Draft Bull Trout Recovery Plan (2002), the Intermountain Province Subbasin Plans (2004), and the Idaho Department Fish and Game Fisheries Management Plan 2007-2012. 

Mack, R. et al. (2000) Biotic invasions: causes, epidemiology, global consequences, and control. Ecol. Appl. 10, 689–710

John M. Syslo, Christopher S. Guy, Patricia E. Bigelow, Philip D. Doepke, Brian D. Ertel, and Todd M. Koel, 2011. Response of non-native lake trout (Salvelinus namaycush) to 15 years of harvest in Yellowstone Lake, Yellowstone National Park Canadian Journal of Fisheries and Aquatic Sciences, 2011, 68:(12) 2132-2145, 10.1139/f2011-122

2. History: Accomplishments, Results, and Adaptive Management (ISRP Review of Results)

Results of past work indicate a number of notable accomplishments to date. The sponsors have demonstrated some success in taking steps to recover native species in tributaries to the Pend Oreille River through eradication or suppression of brook trout. They will be investigating several techniques for reintroducing cutthroat to streams where brook trout have been eliminated or suppressed. The central question at this point is how successful reestablishment of westslope cutthroat in these streams will be. While past work has apparently suppressed non-natives in streams, the challenge is much greater in reservoirs and lakes and success has been limited in those habitats.

Adaptive management also has been demonstrated: “Initially, the Kalispel Tribe attempted to restore native fish habitat. Monitoring results showed that the restoration projects generally increased non-native fish numbers while native fish numbers either decreased or stayed the same.” Since habitat restoration alone was insufficient to recover cutthroat trout, the new strategy is suppression of brook trout, which will need to be carefully monitored to measure success or failure. The sponsor’s seem dedicated to changing strategies if the ones employed do not meet expectations.

A most noteworthy accomplishment is the outreach effort undertaken to gain public support for native species recovery. The sponsors have involved the public in decision-making, apparently resolving public concerns in the process. The sponsors indicate that, through this process, they had achieved public buy-in to support their approaches to native fish restoration.

ISRP Retrospective Evaluation of Results

Results of past work are well described and indicate a number of notable accomplishments to date. The original purpose of the project was a multi-year effort to eradicate brook trout in three streams and reestablish westslope cutthroat trout through translocation of individuals from genetically similar populations. The project appears to have been successful in suppressing brook trout numbers. The central question at this point is how successful reestablishment of westslope cutthroat in these streams will be.

There are three different components in the current proposal: 1) eradicate brook trout in three streams and re-establish westslope cutthroat trout, 2) suppress the northern pike population in Box Canyon Reservoir to benefit native species and game fish, and 3) suppress lake trout populations in Upper Priest Lake in Idaho to benefit bull trout. The first component follows from previous work on brook trout suppression. The ISRP judges northern pike suppression, a new component of the project, to be worthwhile, but request a report in three years documenting progress. In the ISRP’s view lake trout suppression in Upper Priest Lake, which has been ongoing since 1998, has shown little success in reducing lake trout numbers and in significantly increasing bull trout. We deem that it did not meet scientific criteria. 

A most noteworthy accomplishment is the outreach effort undertaken to gain public support for native species recovery. The sponsors indicate that, through this process, they achieved public buy-in to support their approaches to native fish restoration.

3. Project Relationships, Emerging Limiting Factors, and Tailored Questions for Type of Work (hatchery, RME, tagging)

This project is related to the Kalispel Resident Fish Project (199500100), Restoration of Bull Trout Passage at Albeni Falls Dam Project (200704600) and The Joint Stock Assessment Project (199700400), all currently funded through BPA.

The sponsors directly address the emerging issue of the impact of invasive species, namely brook trout, lake trout, and northern pike, on native fishes and will undertake eradication or suppression so as to benefit bull trout and westslope cutthroat. However, many other non-native species such as largemouth bass are present in the Pend Oreille system and potentially can negatively affect native fish populations. The sponsors do not consider how these species will be dealt with. 

The sponsors provide a well thought-out discussion of the possible impacts of climate change on bull and westslope cutthroat trout. The work they are proposing, if successful, should help ameliorate the impacts of climate change on native fishes. However, the impacts of climate change could conceivably favor non-native species, making their suppression more difficult and thus counteracting the proposed measures to reduce climate change impacts on native species. The issues described for climate change, especially for the westslope cutthroat trout and possible expansion of northern pike downstream in the Columbia command attention to the further need for non-native suppression.

The sponsors state, “Monitoring of the effectiveness of this project will be completed by the JSAP (Project #1997-004-00) and WDFW. Overall project effectiveness will be monitored and evaluated annually by Spring Pike Index Netting (SPIN) (Connor et al. in prep) and consultation with a biometrician to determine the relationship between CPUE and overall abundance of northern pike and adaptively develop biologically significant target population level goals. Response of resident species will be periodically evaluated by standardized warm water fish surveys (Bonar et al. 2000).” Clarification of this approach would have improved the proposal. For which aspect of the project will a biometrician be consulted? Also an explanation of “biologically significant target population level goals” would have been helpful.

4. Deliverables, Work Elements, Metrics, and Methods

Most Deliverables contribute directly to accomplishment of the Objectives. The sponsors provide some basic metrics for measuring progress toward their goals. The methods for the most part appear sound. The sponsors have had prior success suppressing brook trout and so are well positioned to conduct suppression in the proposed streams. It would have been helpful if the sponsors had discussed the monitoring activities they will undertake after cutthroat trout reintroduction.

Deliverable 3, “Annually remove at least 75% of the lake trout population in Upper Priest Lake,” like Objective 3 is problematic. The sponsors state that an estimated 75 % of the lake trout in Upper Priest Lake are removed annually by gill netting and yet the population remains stable, presumably due to recruitment within the lake and continued movement of lake trout from Priest Lake through the Thorofare into Upper Priest Lake. If annual lake trout removal is truly 75% of the population it would seem that recruitment and immigration from Priest Lake must be substantial to stabilize the lake trout population. No estimates of recruitment or immigration were provided in the proposal. Alternatively, the 75% removal estimate is a serious overestimate. The estimate was arrived at by using the Leslie Depletion Method. It is uncertain whether this method is appropriate for estimating population abundance in Upper Priest Lake. No information on the model was given, nor was any data provided. Better scientific justification for continuing this component of the project is needed. Furthermore, no clear decision points or criteria for determining success of this project were specified, and consequently it is unclear how long this component of the project will continue or how success will be determined.

Modified by Dal Marsters on 4/17/2012 2:52:51 PM.

There are two distinct components of this proposal: lake trout posing a threat to bull trout in Priest and Upper Priest Lakes, and brook trout posing a threat to cutthroat trout in tributaries. The brook - cutthroat trout portion (Objective 2) is Fundable. This stream work (Lower Graham Creek barrier reconstruction and Cee Cee Ah Creek antimycin treatment) seems justified, and both activities have a reasonable chance for success. Reviewers agree with proposal authors that the controversy regarding proposed use of fish toxicants is a major issue and can only be successful if community members are involved from the onset. These work elements are supportable but need better M&E description. Reviewers note that the program for eliminating or reducing exotic fishes in these situations is appropriately accompanied by methods to prevent them from reinvading.

On other hand, the proposed actions intended to benefit bull trout by suppressing lake trout (all of Objective 1) are Not Fundable. In the preliminary review, the ISRP wondered if it is not likely that bull trout in the lake are already beyond recovery. The response did not present factual evidence regarding that issue, instead indicating a certainty that "members of the Subbasin Work Team, OC, and Technical Coordination Group considered the adequacy and probability of lake trout netting for bull trout recovery prior to incorporating these action items into the Subbasin Plan." The response restated that the removal goal of this project would be to remove 90% of the lake trout from Upper Priest Lake, consistent with the Subbasin Plan.

The ISRP notes the following regarding the status of bull trout in Upper Priest Lake, from the 2003 IDFG report by Liter and Maolie. The 1999 population estimate was 116 adults, with no juveniles being caught. In 2002, the fifth year of gillnetting to remove lake trout, the "situation appeared to worsen for bull trout" when 836 lake trout were netted and the ratio of lake trout to bull trout in the nets was 93:1. In the absence of more recent evidence to the contrary from the project sponsors, coupled with reviewers' experience with the dynamics of lake trout predation, the ISRP must take the position that, while the activities proposed are in good faith and lake trout assuredly pose a serious problem, the actions are being proposed 20 years too late to benefit bull trout.

In the original proposal there was not convincing evidence put forth that either the deepwater trap netting in Upper Priest Lake, or the employment of a strobe light in the Thorofare to deter lake trout reinvasion of Upper Priest Lake, had a reasonable chance for success (and for the effort to benefit bull trout, both those activities would need to be successful). The response provided more detail on the strobe light system proposed as a deterrent to lake trout movement and reviewers agree that trial applications could have merit but only if they were part of program with a reasonable chance of benefit to bull trout. There was no additional information put forth in the response regarding details of the proposed deepwater trap netting in Upper Priest Lake or an appraisal of whether goals would be achievable and adequate for bull trout recovery.