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1994 Columbia River Basin Fish and Wildlife Program
Council document 94-55
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 Fish and wildlife    Fish and Wildlife Program 

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5.0  Mainstem Passage Experimental Program

5.0A  Adaptive Management Approach

Clear answers regarding improvements in survival in the mainstem lie in extensive ecological research, and long-term monitoring and evaluation. At the same time, Congress recognized that these issues would rarely be crystal clear, and directed the Council to make decisions on the basis of the best available scientific information. Most importantly, the condition of many fish populations makes immediate action imperative.

      In 1984, the Council endorsed the concept of adaptive management -- using management initiatives as experimental probes to clarify uncertainties about the effectiveness of mitigation measures. The Council proposes to utilize this management technique explicitly to deal with the mainstem dilemma. Below, we call for significant actions to improve both inriver and transported survival. These actions are coupled with an experimental program intended to maximize our ability to learn and to assist the region in making crucial decisions about mainstem passage.

      The mainstem experiment focuses on an approach to dealing with uncertainty termed ?spread the risk.? A version of this strategy was advanced by the region's fishery managers. It calls for both transportation and inriver passage to be used within each migration season -- basically, dividing the population into two more or less equal groups, one of which is transported while the other group migrates downstream. Thus the survival of the entire migrating population is not totally dependent on the benefits of either strategy. At the same time, through careful experimental design, monitoring and evaluation, the region should be able to learn which mode of passage is best and how survival under each mode is affected by the prevailing environmental conditions.

      This approach is premised on the region's willingness to make within-year evaluation of the two modes of passage an explicit and integral component of the mainstem strategy. Spreading the risk makes sense only as an interim strategy to deal with critical uncertainties that are impeding the region's efforts to craft a fish recovery plan. Clearly, we must ultimately develop an approach that resolves how to use either or both modes of mainstem passage. For this to be possible, the region must be willing to adhere to an experimental program for several years and over a range of conditions.

      The experimental approach has five essential features:

5.0B  Purpose of the Experiment

The experimental program has the following goals: 1) To understand the relative within-year differences in survival to adult return of fish that were transported versus those that migrated in the river over a range of environmental conditions; 2) to refine the hypotheses described below; and 3) to increase our understanding of natural survival processes in the ocean and freshwater, and how these relate to human actions and the success of this program. For each outmigration year, the experiment should compare survival to adult return between fish that were transported and those that migrated in the river under the enhanced survival conditions described below.

      The technical aspects of the design of this experiment are to be developed under the direction of the Independent Scientific Group. The experimental design should describe evaluations needed to address the above questions in terms of impacts to juvenile and adult survival. The design should also describe how smolt transportation should be managed to spread risk as described above and fulfill the needs of the experiment. The experiment will likely require a reduction in the number of smolt collection points, perhaps to a single upriver site. Further, in order to compare the two modes of passage over a range of environmental conditions, the Council expects that the relative proportion of fish in either mode of passage should remain relatively constant. As a result, compared to the situation that has prevailed through much of the 1980s and 90s, fewer fish will be transported in years of low runoff, and more fish will be transported in years of high runoff. Overall, however, the Council expects that this strategy will result in a reduction in the proportion of the migration being transported.

5.0C  Oversight of the Experimental Program

An experiment of this magnitude must include input from a range of interested parties in the region. The Council will use the Fish Operations Executive Committee to provide regional review of the experimental information as it becomes available and to develop strategies to facilitate implementation of the experiment. Because of their respective roles under the Northwest Power Act and the Endangered Species Act, it is also imperative that the Council and the National Marine Fisheries Service work closely together to ensure that this experiment is successful.

Fish Operations Executive Committee

5.0C.1 Approximately every six months and well in advance of the spring/summer migration periods, convene a special meeting to review the existing results of the experiment and problems associated with its implementation.

Council and National Marine Fisheries Service

5.0C.2 Ensure that procedures are in place to provide coordination at policy and technical levels on matters that affect the success of this experiment.

Independent Scientific Group

5.0C.3 Convene and oversee a technical committee to provide technical coordination and experimental design.     

5.0D  Timeline for the Experiment

This experiment attempts to balance two important aspects: 1) the need to take meaningful action to address the needs of declining fish populations, and 2) the need to answer critical scientific questions. Accordingly, the region will proceed with a number of measures aimed at enhancing survival on the basis of the knowledge on hand. At the same time, a considerable expenditure of effort will be focused on the evaluation program to compare the relative benefits of the two modes of fish passage.

5.0E  Mainstem Passage Hypotheses

In this section, the Council states its working hypotheses regarding two key sets of relationships. One relationship is the effect of flow, water velocity and fish travel time on fish survival. The second is the efficacy of smolt transportation for improving salmon survival. These hypotheses underlie many of the actions included in later parts of this section, and are the starting point for the adaptive experiment described above. The Council's reasons for including these working hypotheses are twofold: first, to explicitly state the rationale behind many important measures in the program, and second, given the uncertainties in our knowledge of these relationships, to emphasize the experimental nature of these actions and facilitate their scientific evaluation. In scientific investigation, hypotheses are used to describe phenomena on the basis of existing knowledge and judgment. They are essential starting points for experimentation and an adaptive approach.

      While these hypotheses do not authorize changes in river operations, they do emphasize the need to learn from actions the Council authorizes elsewhere in this program.

      By stating a hypothesis, the Council does not imply that scientific evaluation should supplant action in the mainstem. Indeed, the Council has consistently emphasized the need to take action, but within an adaptive approach that promotes learning and reduces scientific uncertainty. The region is taking a number of actions to improve mainstem salmon survival, and the Council will continue to consider the need for further actions. Many of these actions are controversial and are based on uncertain science. It is necessary, however, to take immediate actions to address the needs of declining fish populations. In stating a hypothesis, the Council's purpose is to ensure that the region learns from taking these actions. The Council is concerned that if the region fails to take aggressive steps to learn now, we will be faced with the same difficult questions 10 years from now, with little better information on which to base choices.

      Much of the controversy surrounding these issues results from conflicting beliefs based on limited and inadequate information. By stating its working hypotheses on how these actions relate to overall fish survival, the Council is providing direction for an adaptive program to address the overarching issue of how to increase the survival of salmon and steelhead in the Columbia Basin. The Council sees the experimental program acting in concert with measures to increase survival based on the best information available at this time. These working hypotheses provide the rationale for actions in the Council's program and, given the uncertainties in our knowledge of these relationships, are intended to guide research and evaluation as part of the Council's adaptive experiment.

      The relationship between actions taken in the river and overall fish survival is not simple. Survival from the smolt stage to adult spawner is the result of a host of factors, only a few of which are under human control. Important relationships can be obscured because improved survival at one life stage can be negated by changes in survival at other life stages. Some survival conditions in the ocean, for example, can vary independently of survival conditions in the river or estuary. Other changes in ocean and other natural survival conditions can also compound human-caused survival bottlenecks.

      In addition, the positive and negative effects of actions taken in the river to improve survival, such as flow augmentation, drawdown and transportation, may be delayed until later life stages. The amount of change in survival that occurs in the river as a result of augmenting water velocity may not tell the whole story. Changes in survival could occur later in the life cycle, particularly in the estuary. The bottom line is how actions affect the return of adult fish to spawn in the Columbia River Basin.

      The Council's hypotheses must be general enough to embrace all of these aspects, while providing enough specificity to guide research and evaluation. In addition to the hypotheses themselves, the Council is providing a list of experimental considerations that expand on the hypotheses and are intended to highlight aspects of the relationship that should be examined in the experimental program. The Council expects the implementing agencies to make all possible efforts to implement quickly an experimental program to address both the hypotheses and the supporting elements.

      For each hypothesis, observations regarding flows, survival and transportation are suggested by the existing scientific information. The Council therefore believes that research to test and refine the hypotheses should include investigation of these elements. Like the hypotheses, these elements are adopted by the Council as guides for further research. The supporting elements are not conclusions or findings, and do not change other substantive measures in the Council's fish and wildlife program.

      As new data are generated and reviewed, the Council expects to refine and improve both working hypotheses. The Council will gear future amendment processes to information generated from the adaptive management process identified in Section 5.0A, and will determine whether further steps are warranted.

Hypothesis I: Flow, Water Velocity, Fish Migration Rate and Survival 

Hypothesis: The Council accepts that there is a relationship between flow, water velocity, fish travel time and survival such that increasing water velocity increases the survival of salmon and steelhead from the onset of active downstream migration to adult spawner. Improvement in the level and frequency of favorable mainstem migration conditions for juvenile salmonids will improve fish conditions, increase migration rates, reduce vulnerability to predators, and improve timing and fitness at entry into the ocean. As a result, survival to adult recruitment will improve to levels that, together with full implementation of other measures in this program, will sustain recovery and rebuilding of salmonid populations.

Background: Major changes in the timing, magnitude and frequency of flows in the Columbia River have occurred as a result of development of the hydroelectric system. Based on evolutionary considerations and the information now available, these changes in the river have likely had a detrimental effect on fish survival.

Existing Information: Like all organisms, the behavior, physical characteristics, and life history of salmon and steelhead are influenced by their environment. Alteration of a fundamental feature of the environment, such as significant changes in flow, water velocity and water temperature, can be expected to affect fish survival and abundance. At the same time, natural survival conditions can change due to drought or changes in the ocean environment. This can compound the effects of human-induced changes in the environment.

      Various attempts have been made over the past decades to evaluate the effects of changes in mainstem flow and water velocity on salmon and steelhead. Most studies have focused on the effect of water velocity on survival during the downstream migration. Examples include the National Marine Fisheries Service's flow-survival studies of the 1970s, predator studies, and correlations between water particle travel time and fish travel time.

      During the 1980s, little new information on the effect of flows on juvenile fish survival was developed. However, recent research using PIT-tagged fish shows promise as a way to evaluate survival of juvenile fish in the mainstem and possibly to the adult return stage as well. Results of some of the recent work may be interpreted to show that survival in some reservoirs could be much higher than estimated from the earlier National Marine Fisheries Service data. However, this research is too preliminary to justify conclusions regarding flows, velocity and fish survival.

      A lesser number of studies have focused on the bottom line -- the relationship between actions taken in the river to augment water velocity and the subsequent return of adult spawners. These include the Marsh Creek (Idaho) study of the survival of spring chinook, other studies of Snake River chinook populations in Oregon and Idaho, and a draft report on summer migrating fall chinook salmon in the Columbia River. The latter report, by investigators at the University of Washington, evaluated the survival rate of mid-Columbia River fall chinook salmon and preliminarily reported a relatively strong relationship between survival and flow during the summer outmigration.

      Many of these studies have been criticized on technical and procedural grounds, and none of them gives crystal clear answers. As part of the process of developing its working hypotheses, the Council funded an independent scientific review of the available data. (The Dr. Cada review referenced earlier.) The reviewers found that the studies were often dated, suffered from inadequate experimental designs, or provided imprecise results. Nonetheless, the reviewers concluded, ?Despite these problems with the existing data sets, the general relationship of increasing survival with increasing flow in the Columbia River Basin still appears to be reasonable.? As a result, the Council believes that these studies provide enough information to support the flow/velocity-survival hypothesis and realizes that further, focused scientific research is warranted.

Uncertainties: The amount of change in survival for a given change in flow or water velocity is uncertain, as is the relative importance of different mechanisms that relate to flow from the juvenile outmigration to the survival of returning adult fish.

Supporting Elements:

  1. The question of interest is how flow and water velocity and transportation affect the survival of fish to their return as adult spawners and the productivity of the populations measured as the ratio between the number of fish returning and their parental spawners.[1]
  2. The biologically important component of the relationship is water velocity. Water velocity can affect fish survival through its effect on other environmental parameters and on fish behavior and condition. Water velocity is affected by flow, reservoir operations and other factors. The rate of downstream movement of actively migrating juvenile salmon and steelhead is positively influenced by the prevailing water velocity. The propensity of juvenile salmon and steelhead to migrate is a function of environmental cues and several factors relating to age and physiological state.
  3. The effect of flow/water velocity could occur at one or more life stages after the onset of active downstream migration. For experimental purposes, these stages can be defined as downstream migration (beginning of migration in the natal stream to below Bonneville Dam), estuarine/early ocean (Bonneville Dam to the first year in the ocean), ocean adult (subsequent years in the ocean) and adult passage (estuary to spawning ground). The experimental program should address the effect of water velocity during the juvenile outmigration on cumulative survival to adult return, including specific impacts at each life stage.
  4. At the estuarine stage, flow/water velocity could influence survival through its effect on migration speed and fish condition. This in turn can affect the date of entry into the estuary to coincide with food availability or predator concentrations and/or by influencing the arrival to the estuary within a physiological window that enhances the likelihood of a successful salt water transition.
  5. The preponderance of information indicates that during the downstream migration, the lowest survival occurs at the lowest flow. At higher water velocities, survival continues to increase but at a decreasing rate. The relationship between flow/water velocity and survival during the downstream migration is defined by a parameter describing the rate of change in survival as flow/water velocity increases (the slope), and a parameter relating to the range of survival expected over a reasonable range of flow or velocity (the intercept).[2] The value of these parameters is uncertain, as is the relationship between inriver survival, as affected by water velocity, and overall survival to adult spawner.[3]
  6. The relationship between water velocity and survival may differ between species or races and could differ between hatchery and wild populations. In particular, the shape of the relationships is likely to be different for yearling (spring migrating) and sub-yearling (summer migrating) chinook
  7. Most of the information on the relationship between flow/velocity and downstream migrant survival relates to chinook salmon and steelhead. However, because sockeye migrate at the same time and at about the same rate as yearling (spring migrating) chinook, hypotheses for the flow/velocity survival relationships for yearling chinook are a reasonable surrogate for sockeye salmon until more specific information can be developed.
  8. Variation in ocean productivity and other natural survival conditions can confound the effects of inriver measures such as flow, velocity and transportation while, at the same time, compounding the effects of human-induced survival bottlenecks. Techniques must be developed to consider and, if possible, correct for these considerations. For example, insight into the effect of ocean conditions might be gained by comparing returns of upriver populations to similar downriver populations and to populations in other river systems on the Pacific Coast with similar life histories.

Hypothesis II: Smolt Transportation 

Hypothesis:  The Council accepts that under some passage conditions, transportation can increase the survival of salmon and steelhead from the onset of active downstream migration to their return as adult spawners relative to survival experienced by fish migrating in the river. Fish migrating in the river include those fish that pass dams through the collection system and are bypassed to the river, as well as fish that pass dams via turbines or spill without entering the collection system.

Background: One tool used to address the survival changes resulting from development of the hydroelectric system is to collect juvenile fish (smolts) at several Columbia River dams and transport them below Bonneville Dam. Limited information indicates that this can improve survival under some circumstances, especially when river conditions are poor.

Existing Information: Most studies of the efficacy of smolt transportation were conducted by the National Marine Fisheries Service during the 1970s. Evaluations also occurred in 1986 and 1989 under more modern conditions. In contrast to much of the work on flow and survival, smolt transportation has been evaluated in terms of its effect on adult returns. Benefits have been measured as the ratio of adult survival rate of transported fish to the survival of fish in the collection system that were not transported.[4] These studies have shown variable results, especially for spring chinook. In general, however, most of the evaluations have indicated a positive relationship under some conditions. Again, none of these studies is conclusive and all have been criticized on technical grounds. For example, a recent Columbia Basin Fish and Wildlife Authority report[5] suggested that transportation may be contributing to declines in wild salmon populations. Conversely, the National Marine Fisheries Service Recovery Team's draft recovery plan argues that the data show relatively clear benefits from transportation.

       The U.S. Fish and Wildlife Service recently funded an independent review of the available transportation data.[6] This review has contributed to the formulation of the Council's hypothesis. While finding fault with the current state of knowledge regarding transportation effects, the review team concluded that the preponderance of evidence indicates that transportation can improve survival of fish to adult return under some adverse inriver conditions. They felt, however, that  there was insufficient evidence to indicate that transportation alone could rebuild upriver runs. For this reason, they emphasized that transportation should be considered an experimental program.

Uncertainties: The amount of benefit and the circumstances under which a benefit is achieved are uncertain. In addition, evaluation efforts to date have not addressed the effect of transportation on adult returns to the spawning ground nor have they examined effects relative to all modes of inriver passage.

Supporting Elements:

  1. The value of transportation should be assessed relative to the alternative of inriver passage over a wide array of conditions using the ratio between adult return rates of transported and non-transported fish. Ultimately, the statistic of interest is the ratio back to the spawning ground.
  2. The benefit of transportation is expected to be inversely proportional to the survival of non-transported fish. Thus, benefits should decrease within a year as the collection point moves downstream and between years as flow and other passage conditions improve.
  3. Survival of transported fish to adult return may be decreased by adverse conditions encountered prior to the collection of juvenile fish due to environmental factors or hatchery rearing conditions, for example.
  4. Transportation benefits are likely to differ among species and populations of fish. In addition, benefits for hatchery fish may differ from those of naturally spawning fish.

5.0F  Research and Monitoring

During the 1980s, the region made unsatisfactory progress in evaluating the relationship between spring and summer flow, velocity and fish survival, notwithstanding concerted efforts by several parties. At the same time, the scientific basis for transportation remains hotly disputed. A lack of direction on these issues has hindered recovery efforts. The importance of these issues is such that continued stalemate is not acceptable. The Council joins with the National Marine Fisheries Service and other regional interests in insisting that these relationships immediately receive the highest priority in the region's research efforts.

      Because of the simultaneous need for action and better scientific information, these relationships can best be clarified through an adaptive management approach. This would involve the use of inriver passage and transportation as management experiments to address the Council's hypotheses. The experimental actions could include a combination of management actions, research, evaluation and monitoring implemented as part of an adaptive management framework. This framework would describe the overall experimental design and link the Council's hypotheses to management and research actions.

      The region needs a process to ensure that the adaptive management framework is developed  in an independent, scientifically credible and open manner. This will have to proceed in close cooperation with the National Marine Fisheries Service and federal river operating agencies. The region should work with the existing research process and make sure that it is coordinated with all interested parties. The primary means for coordination should be through a technical group organized under the auspices of the Independent Scientific Group. This technical group will work with the National Marine Fisheries Service and other agencies to design an adaptive framework. The role of the Independent Scientific Group will be to ensure that the adaptive framework and flow/velocity-survival research is scientifically credible and to keep decision-makers abreast of important developments.

Independent Scientific Group

5.0F.1 As soon as possible, appoint a technical group to work with the National Marine Fisheries Service and other researchers on the design of an adaptive experiment as described in Section 5.0A. The technical group should report to the Independent Scientific Group on a regular basis. The Independent Scientific Group should provide for scientific review of the adaptive framework and ensure that the activities of the technical group are conducted in a scientifically credible manner. The Independent Scientific Group should also ensure that the Council and the National Marine Fisheries Service are kept apprised of the group's progress and communicate the draft adaptive framework to the Council. A draft adaptive framework should be completed and submitted to the Council and the National Marine Fisheries Service by February 15, 1995.

5.0F.2 The Council recognizes that the hypotheses described above are a subset of a larger set of hypotheses, assumptions and facts that underlie the entire fish and wildlife program and link program goals and measures. Collectively, these form the conceptual foundation called for by Bonneville's Scientific Review Group.[7] The Council calls on the Independent Scientific Group to oversee the development of this foundation. The foundation should not be a reinvention of the Council's program, but should seek to define and review the scientific basis for the program. Like the hypotheses described above, the foundation should define the rationale for the program and describe scientific uncertainties that should be addressed. The hypotheses described above are examples of how the foundation might appear. They should be incorporated into the overall foundation. The Independent Scientific Group should prepare a proposal including a detailed description of the foundation concept and a work plan and budget for its development. The workplan should describe how the foundation could be drafted within six months of its approval by the Council. The proposal should be submitted to the Council by January 1, 1995.

Council and National Marine Fisheries Service

5.0F.3 Review the draft adaptive framework to ensure that it addresses the Council's hypotheses and supporting elements, the needs of the National Marine Fisheries Service recovery plan and this program. Evaluate the feasibility of implement-ation. Within six months of receipt of the draft plan provide review and direction for regional efforts to address these issues. However, the intent of the Council is that concrete action to evaluate the hypotheses and supporting elements should begin during the 1995 smolt migration season.

Bonneville

5.0F.4 After approval of the adaptive framework by the Council and National Marine Fisheries Service, fund actions necessary to implement the adaptive framework.

5.0F.5 Continue to fund, on an expedited basis, ongoing evaluations in this research area.

5.0F.6 After Council approval of the proposal from the Independent Scientific Group described in measure 5.0F.2, provide funding and resources necessary for the preparation of a conceptual foundation for the entire fish and wildlife program.

Fishery Managers

5.0F.7 Make available from hatcheries or other appropriate sources the required numbers of juvenile salmon necessary to conduct the flow, travel time and survival studies called for in this fish and wildlife program.

5.0F.8 By December 1, 1995, the fishery managers should provide to the Council for review a conceptual plan for experimental use of pulsing flows to improve salmon migration conditions. Upon Council approval, implement the pulsing experiment.

Bonneville

5.0F.9 On an expedited basis, fund the continued development of PIT tag technology, and other salmon marking techniques for evaluations.

5.0F.10 Fund the installation of juvenile salmon PIT tag detection facilities at John Day and Bonneville dams, to facilitate assessments of naturally producing stocks and improve the quality of monitoring the effects of juvenile and adult fish passage. Installation should be in coordination with the Corps of Engineers, the fishery managers, and the Independent Scientific Group's technical group, according to the following schedule:

Project Installation date
John Day 1996
Bonneville   1996

5.0F.11 Provide funds and resources necessary to enable the Pacific States Marine Fisheries Commission to fulfill measures 5.0F.14 and 5.0F.15, described below.

5.0F.12 Working with the Mid-Columbia Coordinating Committee and the Independent Scientific Group's technical group, determine the steps necessary to install PIT tag detectors on projects in the mid-Columbia River.

5.0F.13 Working with the Independent Scientific Group's technical group, evaluate the merits of installing adult salmon PIT tag detection facilities at selected projects to facilitate evaluation of smolt-to-adult survival. Report to the Council by January 1, 1995, and, on Council approval, install these facilities.

Pacific States Marine Fisheries Commission

5.0F.14 By January 1, 1995, prepare a five-year action plan for development of PIT tag technology and other mark placement and collection practices throughout the Columbia Basin in consultation with the fishery managers and interested parties. Include the steps necessary for installation of PIT tag detectors at projects in the mid-Columbia River, and assess the merits of installing PIT tag detection facilities for adult fish at selected projects. The plan should also assess how to incorporate changing marking and detection technology into the system over time. Report to the Council for review of the plan in January 1995.

5.0F.15 As part of the Coordinated Information System, provide data management capabilities to ensure open and timely access to all mark recovery data.

[1]Studies by the Idaho Department of Fish and Game suggest the relationship between flow in the Snake River and smolt to adult survival for spring chinook shown in Figure 1. Similar relationships have been reported for other Snake River spring chinook populations in Oregon and Idaho and for Mid-Columbia fall chinook. This information should be considered illustrative and not necessarily conclusive.

[2] In Figure 2, and in most representations of this relationship, these parameters are incorporated within an exponential equation. This implies that the rate of increase in survival will decrease as flow or water velocity increase .

[3]  For example, the National Marine Fisheries Service studies during the 1970s suggest the hypothesis shown below as Line A in Figure 2. It has been used in modeling analysis by the fishery managers and the Council. Expansion of estimated predation rates in John Day pool suggest the alternative relationship depicted as Line B, used in analysis by the Bonneville Power Administration. Other hypotheses can be suggested from more recent preliminary information. These hypotheses relate only to the downstream migration portion of the life cycle. It remains unclear how survival during this portion of the life cycle relates to the subsequent return of adults, such as that shown in the Figure 1, above. This information, too, should be considered illustrative and not necessarily conclusive.

[4] There are four ways that fish can pass a hydroelectric project.  They can enter the collection system and be transported, they can enter the collection system and be put back into the river, or they can pass through the turbines or over the spillway without entering the collection system.  Transportation has been evaluated relative to the survival of fish entering the collection system and put back into the river.  It has not been evaluated relative to the third mode of passage.

[5] Ad Hoc Transportation Review Group, Review of Salmon and Steelhead Transportation Studies in the Columbia and Snake Rivers, 1984-89 (December 31, 1992).

[6] Mundy, P.R. et al. 1994.  Transportation of Juvenile Salmonids From Hydroelectric Projects in the Columbia River Basin;  An independent peer review.  U.S. Fish and Wildlife Service, Portland, OR.

[7] Scientific Review Group, 1992.  Critical uncertainties in the Fish and Wildlife Program.  Submitted to the Bonneville Power Administration.

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