ISRP 2023 Follow-up Review of Project #1990-077-00, Development of Systemwide Predator Control (Northern Pikeminnow Management Program)

On September 5, 2023, the Northwest Power and Conservation Council asked the ISRP to review a cover letter and response memorandum (August 31, 2023) submitted by Pacific States Marine Fisheries Commission, Washington Department of Fish and Wildlife, and Oregon Department of Fish and Wildlife, as proponents, regarding Project #1990-077-00, Development of Systemwide Predator Control (referred hereafter as the Northern Pikeminnow Management Program [NPMP]). This project has been reviewed by the ISRP numerous times over the past 25 years, and this particular review dialogue originated in the Mainstem and Program Support Category Review (ISRP 2019-2, May 29, 2019), in which the ISRP recommended the project met scientific criteria with qualifications (i.e., conditions), and the Council requested a response to a number of those conditions. In 2020, the NPMP proponents provided an initial response to the ISRP. The 2020 response demonstrated that the NPMP agreed with the majority of the ISRP's recommendations and intended to explore actions to address them, but it was unclear how and when the recommendations would be addressed. Consequently, the ISRP requested that the three proponents respond collectively to the ISRP review and indicate how the recommended actions would be addressed (ISRP 2020-10). The NPMP's 2023 submittal is intended to address the conditions requested by the Council arising from the ISRP's 2020 response review of the project. The 2023 NPMP response focuses on the ISRP's 2020 requests regarding action implementation and adaptive management, and an explanation of how the condition on SMART objectives would be addressed in the future, as needed.

ISRP Recommendation: Meets scientific review criteria, the conditions are satisfied.

Response issues:

1. Action Implementation

The NPMP response satisfactorily addresses and adopts most of the ISRP recommendations from the 2020 review for improving the northern pikeminnow monitoring and suppression effort via the Sport Reward Fishery. The NPMP established partnerships with the Yakama Nation on stomach content DNA (scDNA) evaluation, and this information will be useful in developing future iterations of the monitoring program to help populate models evaluating smolt consumption rates. The NPMP reallocated funds ($313,000) from the Sport Reward Fishery program so staff could address many of the issues we raised in the 2020 review. This level of effort is acceptable if it is sustained in future years with a continued focus on these issues until they are fully addressed.

2. SMART Objectives

The proponents state that "No SMART objectives are included as there are no new activities proposed at this time. However, if we develop new work for the next review cycle, we will submit SMART objectives to cover the new and existing work." The ISRP still encourages the NPMP to recast current objectives where appropriate to meet SMART criteria for interim RM&E efforts developed within ongoing funded activities and document them in annual reports. This will facilitate development of quantitative desired outcomes with timelines, which will guide the project, inform the Council, and benefit future reviews.

3. Adaptive Management

The partners in the NPMP made substantial progress toward developing a formal adaptive management process. Future adaptive management assessments and NPMP proposals should reconcile differences in measures of abundance of pikeminnows and other predators and the objectives of the program. This could lead to program adjustments reducing the scope of the program to tailraces of dams and other areas of extremely high pikeminnow density where predation exerts a substantial risk to salmon. A fundamental component of the adaptive management system for the project could be to establish "stopping rules" based on established thresholds of pikeminnow abundance and consumption of juvenile salmon and steelhead.

Over the NPMP's 33-year history, the program has been unable to measure a direct response of salmon and steelhead to northern pikeminnow removal based on the sample design and analytical methods applied. Additionally, the proponents' recent study of John Day Reservoir only captured northern pikeminnow in the tailrace of McNary Dam, whereas indices of abundance of smallmouth bass and walleye increased in the sampled areas of the reservoir. If climate warming increases, consumption rates by non-native predatory fish, such as walleye and smallmouth bass, might exert greater predation pressure on salmon as a result of population increases or higher metabolic rates. Moreover, climate change and competition with non-natives could diminish northern pikeminnow abundance as populations of non-native warmwater species increase. The NPMP has the opportunity to evolve and expand its existing evaluation of impacts of non-native predators, and perhaps explore more aggressive management actions for them than currently implemented.

ISRP 2021-05 LibbyMFWPfollow-up1June.pdf