Review of Spring Chinook Salmon in the Upper Columbia River

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In response to a request from the Independent Scientific Advisory Board’s (ISAB) Administrative Oversight Panel (April 2017 memorandum), the ISAB reviewed habitat assessment, research and monitoring, and prioritization and coordination of recovery actions for spring Chinook salmon in the Wenatchee, Entiat, and Methow basins of the Upper Columbia River.

The Upper Columbia Salmon Recovery Board, tribes, state and federal managers, PUDs, and local groups assisted the ISAB in its review. Leaders in these groups presented valuable information to aid our review, including a field review of the Wenatchee and Entiat subbasins and more than 25 presentations. The recovery program in the Upper Columbia Basin is one of the better examples of an explicit strategy to guide local recovery actions, monitoring, and adaptive management.

We provide the following conclusions and recommendations to address the Oversight Panel’s four major questions and to strengthen the Upper Columbia River recovery program:

1. Is the identification of limiting factors for Upper Columbia River spring Chinook based on sound scientific principles and methods?

Scientific principles and methods for identifying factors limiting the recovery of Upper Columbia spring Chinook salmon are generally sound. To improve limiting factors analysis in the Upper Columbia, the ISAB recommends integrating results of freshwater habitat assessments, density dependence analysis, and life-cycle modeling to identify limiting factors across the entire life cycle and geographic range of spring Chinook.

1a. Are Snake River spring Chinook doing better than Upper Columbia spring Chinook, in terms of abundance, diversity, spatial structure, and productivity?

Measures of population-level abundance and productivity for spring Chinook and assessments of habitat are similar in the two Evolutionarily Significant Units (ESUs). Upper Columbia spring Chinook ESU may be exposed to greater risks than the Snake River spring/summer Chinook ESU because they have fewer populations and lower abundance. Our concern is consistent with the findings of NOAA Fisheries when the Upper Columbia ESU was originally listed as endangered and the Snake River ESU as threatened, listings that were not changed in the most recent reviews. The ISAB recommends continued comparison of Chinook recovery in both ESUs with rigorous RME programs to determine which restoration actions are most effective.

1b. Differences between summer Chinook and spring Chinook in the Upper Columbia

Differences between spring and summer Chinook in the Upper Columbia could identify limiting factors for spring Chinook. The ISAB recommends continued investigations of the relative performance of summer Chinook and spring Chinook in Upper Columbia River subbasins. Management actions should be developed to lessen constraints on spring Chinook abundance as information becomes available.

1c. Are pinnipeds potentially a significant source of mortality for Upper Columbia spring Chinook? Can the effect of pinniped predation of Upper Columbia spring Chinook be quantified?

The estimated consumption of all Chinook salmon populations by pinnipeds in the Columbia River increased sharply over the past decade, likely exceeding mortality by fisheries. Impacts varied by pinniped species, salmon life stage, and run timing.

Efforts to quantify effects of pinniped predation on spring Chinook continue to make progress. The ISAB recommends (1) expanding monitoring to assess interactions between pinnipeds and listed species, (2) maintaining predatory pinniped management actions at Bonneville Dam, (3) completing life-cycle/extinction risk modeling, and (4) expanding research on survival and run timing for adult salmonids in the Columbia River estuary and lower Columbia River.

2a. Are habitat recovery actions being prioritized and sequenced strategically? How should habitat projects be prioritized?

The ISAB found the UCSRB’s system for soliciting, reviewing, and designing restoration projects to be scientifically sound with regard to habitat conditions and effects of hatcheries and the hydrosystem. However, the procedure for characterizing cost effectiveness is not quantitative and does not provide a rigorous basis for prioritizing actions, and thus the ISAB recommends applying a transparent cost-effectiveness analysis of each project proposed.

2b. Is there evidence that past projects have improved habitat for this ESU? What types of habitat projects should be prioritized in the future?

Evidence indicates that habitat protection is a high priority, followed by removing barriers, and reconnecting floodplains and side channels. Increasing habitat complexity using log and boulder structures is a useful part of any strategic restoration effort but should be considered a short-term measure that does not substitute for the need to restore processes that maintain channel complexity and supply and retain large wood in rivers. The ISAB recommends that projects that restore and sustain key fluvial and ecological processes should be considered high priority, given predictions for future climate and evidence of successful restoration. A key goal will be to provide habitats that are resilient to changing conditions and extreme events and provide connected habitats to sustain the full range of life history diversity.

2c. How well are actions in other management sectors (all Hs, i.e., habitat and hydrosystem, hatcheries, and harvest) aligned with recovery efforts?

The UCSRB has developed a useful process for prioritizing restoration projects and coordinating recovery actions, but there is no process for integrating the separate efforts of coordinating committees and working groups for the four Hs across the three subbasins. The ISAB encourages the UCSRB and the tribal, state, federal agencies and the public utility districts operating in the Upper Columbia to develop a systematic, collective process for coordination of the actions, monitoring efforts, and decisions across numerous working groups and coordinating committees in the subbasins.

3. Is a research, monitoring, and evaluation (RME) framework in place that can adequately address the questions in #2 above? Can this RME framework provide suitable data to test and validate hypotheses, inform management decisions, and confirm that limiting factors were correctly identified and are being addressed effectively?

Methods of the UCSRB’s Regional Technical Team, public utility districts, and regional fisheries agencies are generally appropriate and can be used to answer questions about effects of hatcheries and the hydrosystem. The RME program focuses largely on assessing hatchery practices and their effects. Currently, there is no RME Plan that encompasses all Hs and their related working groups, and thus the ISAB recommends developing an integrated RME Plan that encompasses all Hs and the Upper Columbia’s related working groups to coordinate monitoring related to all Hs across the three subbasins.

3a. To what extent has the fitness of the Upper Columbia spring Chinook ESU been negatively or positively affected by historical and current hatchery programs in this ESU? To what extent have contemporary supplementation programs provided a demographic benefit to the natural populations?

Contemporary populations of Upper Columbia River Chinook salmon exhibit significantly lowered genetic diversity compared with historical stocks, which included fish from areas above Chief Joseph Dam. Evidence indicates some hatchery programs have altered genetic diversity and fitness of Upper Columbia River Chinook salmon. Current hatchery operations have not increased overall abundance or the abundance of natural-origin spring Chinook, and productivity is not changing. Straying rates in some hatchery programs are quite high and could erode stock specific adaptations.

In view of the lack of response to supplementation programs in the Upper Columbia, the ISAB recommends continued improvement of their hatchery practices and RME program and additional studies to determine why spring Chinook have not responded to supplementation. Additional investigations of genetic diversity and comparison of historical samples with contemporary samples of spring Chinook from the Upper Columbia are also needed to better understand the extent of loss of genetic diversity and likely causes.

4. Are the life-cycle and habitat models in development for the Upper Columbia ESU useful for informing the identification, prioritization, and evaluation of restoration actions?

In general, the life-cycle models being developed will be useful to investigate the relative impacts of restoration actions because they can be scaled up to larger spatial and temporal scales. Currently, the models are useful for ranking the relative benefit of management actions at the population level but not for predicting exact numerical responses. The ISAB recommends continued development of the life-cycle models, using the life-cycle models to rank proposed restoration actions, and incorporating their results in analysis of cost effectiveness. Multiple models can be compared to better understand uncertainties and responses to limiting factors.

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