Independent Scientific Advisory Board 

Report on Harvest Management of 

Columbia Basin Salmon and Steelhead 

 

June 21, 2005 

ISAB Harvest Report 

ISAB 2005-4
Independent Scientific Advisory Board

for the Northwest Power and Conservation Council,

Columbia River Basin Indian Tribes, 

and NOAA Fisheries

 851 SW 6th Avenue, Suite 1100

Portland, Oregon 97204

ISAB@nwcouncil.org

Robert Bilby, Ph.D., Ecologist at Weyerhaeuser Company an expert in riparian ecology.

Peter A. Bisson, Ph.D., Senior Scientist at the Olympia (Washington) Forestry Sciences 

Laboratory of the U.S. Forest Service.

Charles C. Coutant, Ph.D., Distinguished Research Ecologist, Oak Ridge National Laboratory, 

Oak Ridge, Tennessee, Past President of the American Fisheries Society, with expertise in 

fish-habitat relationships. 

Daniel Goodman, Ph.D., Professor of statistics at Montana State University, an expert in 

ecological risk assessment. 

Susan Hanna, Ph.D., Professor of resource economics at Oregon State University (also an 

IEAB member). 

Nancy Huntly, Ph.D., Professor of wildlife biology at Idaho State University.

Eric J. Loudenslager, Ph.D., ISAB Chair, Hatchery Manager at Humboldt State University, 

California, an expert in genetics and fish culture. 

Lyman McDonald, Ph.D., Consulting Statistician at Western Ecosystems Tech., Inc., 

Cheyenne, Wyoming, formerly Professor at the University of Wyoming. 

Gary Morishima, Ph.D., Consulting Fisheries Scientist, an expert in the biology of Pacific 

salmon and international fisheries management. (Ad Hoc Member) 

David P. Philipp, Ph.D., Principal Scientist at the Illinois Natural History Survey and Professor 

at University of Illinois, an expert in conservation genetics and reproductive ecology. 

Brian Riddell, Ph.D., Senior Scientist at the Pacific Biological Station, Department of Fisheries 

and Oceans Canada, Nanaimo, British Columbia, an expert in the biology of Pacific salmon 

and international fisheries management. (Review Lead) 
Acknowledgements 

Many individuals and institutions helped the ISAB undertake the harvest review assignment. We 

thank the following individuals for providing presentations on harvest management of Columbia 

River Basin salmonids to the ISAB: Chuck Tracy (Pacific Fishery Management Council), Mike 

Matylewich (Columbia River Inter-Tribal Fish Commission, “CRITFC”), and Peter Dygert, 

Robert Kope, Susan Bishop, Norma Jean Sands and Jeff Hard (NOAA Fisheries). We thank the 

past and current ISAB Ex Officios and science coordinators for organizing presentations, 

refining questions, and remaining patient and supportive of our extended review: Phil Roger 

from CRITFC, Mike Schiewe, Mike Ford, and Bill Muir from NOAA Fisheries, Chip 

McConnaha, Steve Waste, and Erik Merrill from the Council. We also thank Council staff 

Kierstan Dodd for assistance formatting tables, and Kris Jenkins for the cover graphics. 

We thank the Native Fish Society for its persistent interest in the ISAB review and providing 

questions that were incorporated in the Council, NOAA Fisheries, and CRITFC questions to the 

ISAB. 

Dr. Gary Morishima participated as an ad hoc member on the review team and provided 

invaluable insight and material for this report. His participation is gratefully acknowledged.
ISAB 2005-4 Harvest Report 

ISAB Report on Harvest Management of Columbia Basin Salmon and Steelhead 

Executive Summary........................................................................................................................ ii 

1. Introduction................................................................................................................................. 1 

2. Harvest Management: An Evolving Discipline .......................................................................... 3 

2a. Evolution of Three Key Concepts.......................................................................................................5 

2b. Environmental Uncertainty.................................................................................................................6 

2c. Uncertainty in Production Assessment ...............................................................................................7 

2d. Uncertainty in Management Control ..................................................................................................8

3. Current Institutional Structure for Harvest Management Decision Making............................... 9 

3a. Many Managers, Many Challenges ..................................................................................................11 

3b. Legal Requirements for Harvest Management .................................................................................15 

3c. The Decision-Making Process..........................................................................................................18 

3d. The Task Today................................................................................................................................21

4. ISAB Review ............................................................................................................................ 24 

4a. Vision Statement...............................................................................................................................24 

4b. Indicators of effective harvest management systems .......................................................................26

Performance Indicator 1: Is the Scientific Foundation sound?...........................................................................26 

Performance Indicator 2: Are there clearly defined management objectives? ...................................................33 

Performance Indicator 3: Is there adequate institutional capacity to constrain total fishing mortality?.............35

5. ISAB Recommendations........................................................................................................... 38 

6. Questions Posed to the ISAB.................................................................................................... 42 

7. Background Sections ................................................................................................................ 49 

7a. Sustaining Diversity..........................................................................................................................49 

7b. Freshwater Ecosystems.....................................................................................................................51 

7c. The Hatchery Paradigm and Ocean Carrying Capacity....................................................................55 

7d. Climate Change and Potential Salmon Harvest................................................................................58 

7e. A Primer for Salmon Harvest Management.............................................................................. 63

8. Literature Cited by Sections...................................................................................................... 76 

Appendix A. Harvest Management Functions for Three Columbia River Basin Stocks ............. 87 

Appendix B. Table of Columbia River Salmonids organized by Ocean, In-River, and ESA 

Management Units........................................................................................................................ 98 

Appendix C. Supplement to Questions, Section 6; Reductions in Fishery Impact Rates for Three 

Columbia River Salmon Populations.......................................................................................... 104 

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ISAB 2005-4 Harvest Report 

ISAB Report on Harvest Management of Columbia Basin Salmon and Steelhead

Executive Summary 

This report focuses on the role of harvest management in the conservation and sustainable use of 

salmon and steelhead from the Columbia River system.

1

 With an interest in clarifying how 

harvest interacts with habitat, hydro, and hatcheries (the other H’s) in the Columbia River Basin, 

the Northwest Power and Conservation Council, NOAA Fisheries, and the Columbia River 

Intertribal Fish Commission developed a series of harvest-related questions and requested the 

Independent Scientific Advisory Board (ISAB) produce a report that addresses those questions. 

The ISAB’s review of the current scientific and institutional structure for harvest management 

leads to answering four questions that encompass the questions posed by the sponsors. The 

report also provides brief reviews of past management practices, current institutional structures 

for harvest management of Columbia River salmon,2

 and background information on five topics 

related to salmon production and harvest management, including an introductory description of 

harvest management terminology and practices (Section 7e) for people less familiar with this 

topic. Although harvest management and salmon recovery can be assisted by the use of “best 

available” science, science alone is not sufficient. Science serves as the basis for harvest 

management decision making, but management also comprises differing cultural and socioeconomic perspectives. 

The ISAB is impressed with the management processes that have been developed and the 

continued efforts to expand the scientific basis for recovery of depressed populations of naturally 

produced salmon and steelhead. The elements of science, commitment, cooperation, and 

investment are all evident and progressing in the Columbia River Basin. We remain, however, 

concerned about the conservation of naturally produced salmonids and the relative effect of 

harvest on their conservation. Harvest is only one part of this complicated picture, but fishing is 

frequently targeted as a first management action because it removes mature salmon that could 

otherwise return to reproduce. 

Components of effective harvest management systems 

Within the context of this assignment, the ISAB’s vision of conservation and sustainable use is 

centered on decision processes that are necessary to ensure that the removal (i.e., total mortality 

from all sources) of Columbia River salmon does not exceed the productive capacities of 

 

1 The terms conservation and sustainability involve diverse perspectives and values, resulting in different meanings

for different people. The terms embed implicit references to objectives, time horizons, discount rates, and tradeoffs, 

which take on explicit meaning only when defined for a particular context. Neither term can be defined in the 

absolute, because each combines economic and social, as well as biological and ecological, elements in varying 

combinations. The ISAB did not attempt to develop specific definitions of these terms, recognizing the diversity of

issues involving salmon and people in the Columbia River Basin. 2

 Throughout this report, when the term “salmon” is used in a general sense, it is meant to encompass salmon and 

steelhead, “salmonids.” 

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naturally spawning populations over the long-term. From this perspective, effective harvest 

management systems must have three primary components: 

1. A sound scientific foundation for management; 

2. Clearly defined priorities and objectives for resource conservation and fisheries 

management; and 

3. The capacity to constrain total fishing mortality on a population to a level that proves 

sustainable after accounting for all sources of mortality throughout the population’s life 

cycle. 

1. Sound Scientific Foundation

Science must effectively inform decision making for harvest management. Science is involved in 

designing monitoring programs, collection of data, and the development and use of reliable 

methods of analysis to assess biological status of the populations and fishery impacts. These 

assessments frequently involve limited data or data that vary in quality though time, and “noisy” 

data from complex ecological and social systems. Most types of information collected about 

Pacific salmon involve large variability (and/or limited predictability) due to natural variation in 

environmental conditions, changing habitat conditions over time, and the complex interactions of 

biological communities and salmonid ecosystems. A sound scientific basis for harvest 

management would: (1) provide the best practically obtainable and pertinent data; (2) provide the 

“best available science”3

 at the time decisions are made; (3) appropriately account for 

uncertainty, and (4) ensure transparency for the basis of advice, analyses, competent peer review, 

and a process for regular review and response (learning) as experience is gained. 

Given the uncertainties and unknowns that remain in salmon management and recovery, a 

priority should be placed on ensuring a stronger empirical basis for assessing trends and status in 

each production unit, and on obtaining key information required to control harvest impacts. 

Well-designed monitoring programs are required to collect data on fisheries and escapements. A 

sound scientific basis for harvest management would inform decision-makers of the need for 

better information as harvest approaches the limits sustainable by the productive capacity of the 

resources as well as of the trade-offs between uncertainty and costs of management. In the 

absence of adequate data, managers should reduce impacts on the resource to ensure its 

continuance and future productivity. 

2. Clearly Defined Management Objectives

Effective harvest management requires: (1) definition of the production units4

 to be managed; (2) 

biological conservation targets for each production unit; and (3) objectives and priorities for 

fisheries and clearly defined risk tolerances. 

 

3

 The Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA) requires that harvest management

decisions use the “best available science.” The MSFCMA contains ten National Standards for fishery management

plans, and guidelines for implementing these standards are applied in decision-making processes of regional fishery

management councils (see discussion of current institutional structure). 4

 Production unit in this discussion is a spatially defined group of salmon populations and hatcheries that are 

determined by the responsible agencies as a basis for conservation and management. Typically, each unit would be

demographically independent and there could be several such units within an ESU. 

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Recent identification of independent population units is notable progress in characterizing the 

resource base, but conservation targets are not as well defined and are often not fully integrated 

with harvest management capabilities. For instance, although component populations of 

Evolutionarily Significant Units (ESUs) can be identified, little data may be available to 

determine the level of harvest that can be sustained by those individual components, and 

fisheries may be regulated through the use of indicators of population aggregates. 

Objectives for harvest management include biological, legal, and socio-economic considerations. 

Biologically, harvest impacts must be constrained to lie within the productive capacity of the 

populations that comprise the resource base. Legally, harvest management must comply with 

international and Indian treaty obligations, as well as requirements set forth in federal, state, and 

tribal law. Socially, harvest management must distribute the benefits of harvest and 

responsibilities for conservation in a manner that is acceptable to the public and defensible 

against legal challenge. The suite of harvest management objectives affecting Columbia River 

salmon is embodied within management plans and legal requirements, such as the Pacific 

Salmon Treaty agreements, the Pacific Fishery Management Council’s Pacific Coast Salmon 

Plan, the recently agreed “2005-2007 Interim Management Agreement for Upper Columbia 

River Chinook, Sockeye, Steelhead, Coho and White Sturgeon (U.S. v. Oregon Parties 2005)”, 

and the Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA). 

In spite of all of the data that have been collected on Pacific salmonids, the reality is that 

fisheries management is inexact. There are many sources of uncertainty, but science must 

provide information and advice in the face of both risk and uncertainty. Risk can be minimized 

and future options preserved in a dynamic and unstable environment by maintaining a 

genetically diverse mix of component populations and their habitats. A sound harvest 

management decision process would protect a minimum spawning population size in each unit, 

given the current and potential future range of environmental conditions and the range of error in 

assessments. 

3. Capacity to Constrain Total Fishing Mortality 

The capacity to constrain harvest of Columbia River salmon requires: (1) consistent qualityassured data for pre-season planning and in-season monitoring; (2) clear management objectives 

and timely in-season decision processes; and (3) management accountability. 

With a multitude of institutions having regulatory authority over Columbia River basin fish, 

there would seem to be ample opportunity to constrain total fishing mortality through both 

regulations and enforcement. Unfortunately, the distribution of responsibility for achieving the 

biological conservation targets for individual production units is fraught with such controversy 

that the aggregate result is often less satisfactory than required. 

 

The capacity to constrain harvest of Columbia River salmon is determined by the institutions 

involved in regulating fisheries throughout the migratory ranges of individual production units. 

The institutional structure of harvest management is extremely complex, involving many private, 

local, regional, state, tribal, federal and international entities. Because many jurisdictions 

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typically affect the harvest of Columbia River salmon, fishery management decision processes 

must be sufficiently coordinated to collect consistent biological data and accomplish 

management objectives for production units of interest. These entities operate within their own 

jurisdictions, but often have overlapping authorities and responsibilities. 

The ISAB recognizes that some of the limitations on constraining harvest mortality are due to 

basic inability to scientifically sort out population dynamics and total mortality for individual 

populations involved in multiple, mixed-stock fisheries. For an escapement objective for each 

salmon population to be achieved, not only must management define the desired number of 

spawners for each population, it must also regulate multiple fisheries to achieve them. This level 

of harvest management control in salmon fisheries is unrealistic because most fisheries 

simultaneously exploit a mixture of salmon populations and the actual catch by stock is usually 

unknown. Additionally, errors in pre-season forecasts, changes in return timing, variation in the 

response of fishermen to opportunities, and weather all confound our ability to accomplish 

management objectives for individual production units. Further, in the context of managing 

fisheries, it is important to differentiate what is known about salmon and our capability to control 

harvest impacts on specific populations. The latter is referred to as management control error and 

is frequently not fully accounted for in planning. 

Concerns 

The issues involved with harvest management are complicated, with many agencies and salmon 

populations involved and numerous legal requirements and historical complications (past 

impacts of development, mitigation and legal backgrounds including the massive hatchery 

production, conflicting objectives, limited historical data, etc.). Significant progress, however, is 

being made in several areas important to harvest management, such as the definition of 

independent population units, development of criteria for population and ESU viability, 

establishment of the Pacific Salmon Treaty and the role of the PFMC in limiting ocean fishing 

impacts, the renewed in-river fishing agreements, and recent efforts to integrate analysis of the 4-

Hs in determining salmon production. While the ISAB has been favorably impressed with the 

development of biological science and management processes, three fundamental components of 

harvest management are noted as significant concerns. These include: 

1. insufficient quantitative data for analyses by production units; 

2. very limited evidence of stock assessment analyses by production units to provide a 

biological basis for production goals and trends in status; and 

3. limited evidence of accounting for uncertainty in management plans with the exception of 

reference to precaution in the National Standard Guidelines established under the 

MSFCMA. 

Given the severe limitations of historical data, the complex interactions of the 4-Hs, and the 

number of salmon production units listed under the ESA, managers should clearly reflect on the 

appropriateness of harvest rates, their ability to control fisheries, and their ability to explain the 

status and trends in Columbia River salmonids. A serious commitment to acquiring the empirical 

data for annual stock assessments, achieving the target spawning escapements (or exploitation 

rate), and explaining deviations is essential to function within the complex management 

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ISAB 2005-4 Harvest Report 

processes involved with Columbia River salmonids. Establishing this empirical basis will serve 

to reduce management uncertainty and debate between agencies, focus attention on actions most 

necessary to recovery listed-species, and account for harvest impacts when fishing occurs. The 

ISAB has emphasized the need for improved quantitative information in two other recent reports: 

the review of subbasin plans (noting the lack of rigorous stock assessments in many subbasins) 

and the supplementation review (noting the information needed for assessments). Improving the 

information quantity and quality will not, however, stop debates over harvest. Conflicts in 

harvest opportunities between hatchery and natural stocks, between species, and between cultural 

and socio-economic values will continue. The value of improved information in this context, 

though, is that accurate assessment of harvest impacts may enable: (1) compensatory actions in 

the other H’s (i.e., integration of mortalities through the life cycle of the salmon); (2) 

reconsideration of management objectives (e.g., are time scales of recovery realistic?); and (3) 

review of the relative values and costs associated with this harvest impact. 

Recommendations 

Based on our review and questions posed by the sponsors, the ISAB presents four 

recommendations: 

1. Core Monitoring Data 

There is an essential need for a core set of quantitative data to be monitored annually in all 

production units or, at least, in a sub-sample of units that may be used as representative 

indicators of productivity and trends in abundance over time. With the obvious importance of 

defining recovery goals and then monitoring progress to recovery, establishing quantitative 

indicator systems within ESUs is required for a credible harvest management system. A 

monitoring framework with probabilistic sampling designs should be required for each ESU and 

population unit defined by the Technical Recovery Teams, as well as for stocks that are not 

listed. These data collected annually provide for the critical analytical assessments necessary to 

advise management and selection of recovery actions. The ISAB strongly cautions against the 

collection of data without parallel careful design, use, and evaluation. 

2. Documented Assessments 

While the ISAB reviewed many reports, biological opinions, scientific papers, and management 

plans, there were very few quantitative and documented analytical assessments of individual 

production units or ESUs. Such assessment reports would typically provide the basis of 

biological advice on Pacific salmon that subsequently becomes the basis for harvest management

planning. Detailed assessments must be documented and peer reviewed to provide quality 

control to the scientific basis of management planning. 

3. Accounting for Uncertainty

While many documents refer to uncertainty, there were very few examples of actually estimating 

uncertainty or accounting for it in a management plan. Analysts likely know much less about the 

production dynamics of Pacific salmonids than is assumed, and uncertainty is very likely to be 

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ISAB 2005-4 Harvest Report 

much greater than appreciated or accounted for. Guidelines for the estimation and accounting of 

uncertainty in management targets and in-season management control should be developed and 

applied. All sources of fishing mortality must be accounted for and a level of risk tolerance 

established through public consultation. While the ISAB was impressed with the intensive 

process used for salmon management, we also recommend analysts review whether current 

levels of harvest impact are consistent with the quality of data and level of uncertainty in the 

biological and management processes, and provide the expected likelihood of recovery for these 

listed species. 

4. Adaptive Management in Salmon Recovery 

Given the limitations in historical data, the limited progress on recovery planning, the inherently 

large uncertainty, and the complexity of management processes involved in harvest management

of Columbia River salmonids, the ISAB recommends application of adaptive management 

principles in salmon recovery. Although the ISAB acknowledges potential problems with 

implementing a truly adaptive program in such a complex environment, the ISAB believes that a 

systematic approach to testing alternative actions with an emphasis on achieving secure 

spawning escapement levels should again be seriously considered. Such alternative actions may 

include stepped harvest rates weighted to protect minimum spawning levels, manipulations of 

hatchery production and/or the hydrosystem flows, and testing of incentives for recovery. 

Recommendation 4 may also be an appropriate action for addressing how the Columbia River 

Basin should assess and adapt to the risks of climate and ocean changes on Columbia River 

salmonids. As discussed in Section 7d of this report, the ISAB anticipates significant increases in 

understanding of climate and ocean changes and cycles in relation to salmon and other natural 

resources in the next few years, and significant increases in the uncertainty of production 

forecasts in the short to medium term. Harvest managers and the harvest industry need to be in 

close touch with this understanding and adjust their procedures accordingly for conducting 

assessments, setting allowable harvests, and harvesting fish. 

ISAB Reply to Sponsors’ Questions 

1. Contrast current and past harvest practice, addressing whether harvest rates and total fishing 

mortality on Columbia River stocks have increased, decreased, or remained constant? 

Fishery impacts on Columbia River salmon have been reduced since the mid-1980s due to 

harvest management measures taken to respond to a variety of factors. The reductions have not 

been equal across species but three examples are presented in Appendix C to illustrate reductions 

in fishery impacts on Columbia River salmon and discuss underlying reasons: (1) Upriver Bright 

Fall Chinook (URB); (2) Coho; and (3) B-Run Steelhead. 

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ISAB 2005-4 Harvest Report 

2. Does current harvest management adequately manage and protect ESA listed naturally 

spawning populations? 

 This question cannot be definitively answered until recovery objectives are established for ESAlisted populations, determinations are made as to which component populations within ESUs 

must be protected to maintain their viability, and quantitative risk tolerances are adopted. Until 

then, ambiguities will continue to surround interpretation of the phrases “adequately manage and 

protect” and “ESA-listed naturally spawning populations.” Under the current system of ESA 

administration, NOAA Fisheries and the U.S. Fish and Wildlife Service have the responsibility 

to determine whether or not management measures are “adequate” to protect ESUs. In the 

absence of approved recovery plans and a quantitative risk standard, and a comprehensive 

quantitative methodology for assessing risk and factoring the uncertainties into that assessment, 

agencies have considerable latitude in implicitly defining “adequacy” in their jeopardy findings 

and the annual guidance they provide for harvest management. 

The current focus on “adequacy” should be squarely placed on whether management measures 

are sufficient to make predictable progress toward population recovery on the basis of those 

factors that are reasonably well-characterized, and maintain options, avoid irreversible damage, 

and monitor status with respect to factors that are very uncertain. Because of the potential for 

rapid adjustment of harvest, and given the existence of systems that collect and analyze data in a 

timely manner to monitor impacts, harvest management measures can be adjusted both annually 

and in-season. Consequently, harvest management is much more likely to be capable of 

preserving options for recovery than other types of measures that may be involved, such as 

habitat improvements or modification of flows and dam passage facilities. This greater 

flexibility, however, carries the liability that harvest management may be called upon to bear a 

greater share of the conservation burden in a crisis situation. It is essential to note, though, that if 

the predominant limiting factor to recovery is not harvest, then those other factors must be 

addressed, or the value of reduced harvest will be temporary and not sufficient for recovery. 

3. What are the consequences of mark-selective fisheries on the accuracy and precision of 

forecasting and on consideration of harvest regime options? Are there practical measures that 

could be implemented in the short- or long-term to address the challenges posed by markselective fisheries? 

Generally, mark-selective fisheries can be expected to increase uncertainty in harvest 

management of natural (unmarked) stocks, in terms of both precision and bias. The 

consequences of mark-selective fisheries are situational. Depending on the location and intensity 

of harvest, mark-selective fisheries may or may not have a significant effect on a variety of 

harvest management tools, such as estimation and forecasting of in-season run size. The reports 

of the Pacific Salmon Commissions Selective Fishery Evaluation Committee identify and discuss 

potential effects of mark-selective fisheries on harvest and management tools (ASFEC 1995). 

Additionally, a report in preparation by the Expert CWT Panel convened by the Pacific Salmon 

Commission in June 2004 will address this issue in depth. 

Two important factors should be recognized when dealing with mark-selective fisheries. First, 

the capacity to conduct mark-selective fisheries depends upon continued investment in hatchery 

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production and mass-marking. There are significant ecological risks associated with developing 

fishing strategies that depend on sustained hatchery production that should not be cavalierly 

dismissed (e.g., density-dependent competition and/or predator dynamics involving interactions

of hatchery and naturally produced juveniles). Second, the costs of mass-marking, double index 

tagging, and sampling/reporting programs for catch and escapement will likely strain agency 

budgets and result in reduction of services or other programs, such as data collection, research, or 

enforcement. If investments are not made to improve sampling and reporting programs, 

management uncertainties will increase and impose costs to compensate. 

4. Are analytical tools sufficient to adequately track future harvest rates? If not, what tools or 

performance standards will be most effective for managing fisheries? Are there opportunities to 

use PIT tags to improve management capabilities and reduce uncertainty? 

Harvest management of Columbia River salmon involves a number of data collection systems 

that monitor impacts and analytical tools to evaluate results. The determination of “adequacy” of 

these tools, however, is situational and beyond the capabilities of ISAB to evaluate in this report. 

An independent analysis may be helpful to provide an in-depth evaluation of current tools and 

methods and to develop recommendations for improvement. 

To-date, much of the information employed for the management of Columbia River salmon is 

derived from analysis of coded-wire tag (CWT) data. Analysis of CWT recovery data must 

frequently involve statistical inference because this technology is based on group marking and 

single recoveries (sacrificial sampling is required to recover data) of individual members of a 

group. These characteristics require assumptions and interpretation to address questions of 

interest to managers and researchers. Coded-wire tag technology is over thirty years old. 

Newer technologies are now available and capable of providing data and information that is 

unattainable from coded-wire tags. One of these technologies is the passive inductive 

transmitting (PIT) tag that can potentially provide data for estimation of natural and release 

mortality rates, migration patterns and rates, and growth rates. Additionally, since data from PIT 

tags can be recovered without mutilating the fish, market values of the fish are not affected, 

thereby eliminating the barriers to processor and fishermen cooperation. The region should begin 

planning of long term monitoring of life history parameters, including harvest mortality, of 

hatchery and wild fish by use of PIT tags. The potential application of PIT tags in harvest 

management is being considered by the Coded-Wire Tag Expert Panel of the Pacific Salmon 

Commission, which will be reporting in the summer 2005. 

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ISAB 2005-4 Harvest Report 

ISAB Report on Harvest Management of Columbia Basin Salmon and Steelhead 

1. Introduction 

Salmon contribute to ecosystems, cultures, and economies of Native and non-Native Americans 

in the Pacific Northwest. Juvenile and adult salmon and steelhead are keystone species in both 

freshwater and marine environments. Adult salmon returning from the ocean provide important 

nutrients to watersheds, and juvenile salmon in freshwater are dominant members of many 

aquatic communities. Each year, the salmon resources of the Columbia River Basin are included 

in extensive fishery management processes upon which numerous peoples and communities 

depend. Native Americans, for thousands of years, have relied on salmon for food and celebrate 

salmon in their culture. As the status of Pacific salmonids has declined, however, questions have 

been raised about the present biological and scientific basis for their conservation, and, in 

particular, whether or not harvest management overall is consistent with recovery in the 

Columbia River, most particularly for those listed under the Endangered Species Act (ESA). The 

discussion about harvest, though, is not only about fish and statistics; any discussion of harvest 

inherently includes scientific and humanistic issues. The history of Pacific salmon in the 

Columbia River Basin exemplifies the conflict between conservation, non-Native fisheries, 

cultural and food values of Native fisheries, and competing economic developments in the 

Columbia River Basin (i.e., the other 3-H’s: Hydro, Habitat, and Hatcheries). This report 

addresses the fundamental topic of what now constitutes a sound scientific basis for harvest 

management of Pacific salmonids originating in the Columbia River Basin. 

Harvest, and harvest-related mortality such as bycatch or sport fishing catch-and-release 

mortality, is only one of several sources of the total mortality experienced by a salmon 

population over its life cycle. Harvest is a human activity, highly visible, and considered 

controllable (i.e., annually managed and subject to regulation). Furthermore, harvest largely 

affects salmon that have survived to maturity and are returning to their natal rivers to spawn. 

Harvest, therefore, can have a significant and immediate effect on the numbers of adults 

returning to spawning populations. Achieving a desired abundance and distribution of spawning 

salmon is a matter of balancing all sources of mortality throughout the life cycle of a salmon 

population. There are a limited number of animals in any population that can be killed and still 

have the population sustain a desired status. How those deaths are “allocated” through the life 

cycle, through environmental variation, and in relation to various activities that are the cause of 

the mortality, is, however, a management question of considerable complexity. 

With an interest in clarifying how harvest interacts with other H’s in the management of 

Columbia River Basin salmon, the ISAB’s sponsors, the Northwest Power and Conservation 

Council (NWPCC, aka Council), NOAA Fisheries, and the Columbia River Intertribal Fish 

Commission (CRITFC) developed a series of harvest-related questions and requested that the 

ISAB produce a report that answered those questions. The Council asked 14 multipart questions. 

Those questions were combined into three broad topics: (1) does harvest management adequately 

manage and protect naturally spawning populations; (2) are there opportunities for more 

selective-type fisheries, and can artificial production be used to help reduce mixed-stock 

fisheries; and (3) are there sufficient management tools, including institutional arrangements, in 

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ISAB 2005-4 Harvest Report 

place to adequately manage ocean, near-shore and inland fisheries. NOAA Fisheries asked the 

ISAB to contrast current and past harvest practices, provide practical advice on mark-selective 

fisheries for hatchery-origin fish, and consider how PIT tags might be useful to improve 

management capabilities and reduce uncertainty. CRITFC asked the ISAB to identify data needs 

and describe the current accuracy and precision of estimates used in management decisions, and 

then to identify achievable, short-term actions to better achieve integration and implementation 

of harvest measures. 

The ISAB’s goal for this report was to explain clearly: the biological basis and management 

processes involved in providing and controlling harvest, how uncertainty in information and 

parameter estimates can be accounted for in decision making process, and to explain how harvest 

may be integrated with recovery objectives. For those less informed about the technical basis for 

this topic, the report includes a brief Primer (Section 7.e) as background to salmon assessment 

methods and harvest management processes. 

This report has focused on the technical issues associated with harvest management and 

integrating harvest with the total mortality of salmonids throughout their life cycle. Subtopics 

include the challenge of managing for smaller population groups given current assessment 

technologies, the role of salmon in the ecosystem, the assessment of harvest within a life cycle 

and recovery context, and challenges arising from the complex institutional arrangements 

responsible for making harvest management decisions. To provide context, the review includes a 

summary of our current understanding of the effects of climate variability on the marine 

environment and the interplay of harvest, hatchery production, and varying ocean regimes. 

This report was produced by an extensive ISAB effort over the last two years. The review was 

informed by briefings, analyses contained in agency reports, material in the primary peerreviewed literature, and some independent analysis of data. Representatives from the Pacific 

Fishery Management Council and Columbia River Inter-Tribal Fish Commission briefed the 

Board on ocean and in-river harvest management. NOAA Fisheries’ Sustainable Fisheries 

Division briefed the ISAB on their approach to consultations for harvest pursuant to their 

responsibilities under the Endangered Species Act (ESA). ISAB members and Dr. Gary 

Morishima (ad-hoc committee member) presented on the Pacific Salmon Treaty and analytical 

tools used to develop and evaluate harvest levels. 

Synopsis: The ISAB is impressed with the management processes that have been developed and 

the continued efforts to expand the scientific basis for management and recovery. The elements 

of science, commitment, cooperation, and investment are all evident and progressing in the 

Columbia River Basin. We remain, however, concerned about the conservation of naturally 

produced salmonids and the relative effect of harvest on their conservation. Harvest is only one 

part of this complicated picture, but fishing is frequently targeted as a first management action 

because it removes mature salmon that could otherwise return to reproduce. 

The issues involved with harvest management are complicated, with many agencies and salmon 

populations involved and numerous legal requirements and historical complications. Significant 

progress is evident in several areas important to harvest management, such as the definition of 

independent population units, criteria for population and ESU viability, establishment of the 

2 
ISAB 2005-4 Harvest Report 

Pacific Salmon Treaty and role of the PMFC in limiting ocean fishing impacts, the renewed inriver fishing agreements, and recent efforts to integrate analysis of the 4-Hs in determining 

salmon production. While the ISAB has been favorably impressed with the development of 

biological science and management processes, three fundamental components of harvest 

management are noted as significant concerns. These include: 

4. insufficient quantitative data for analyses by production units; 

5. very limited evidence of assessment analyses by production units to provide a biological 

basis for production goals and trends in status; and 

6. limited evidence of accounting for uncertainty in management plans with the exception of 

reference to precaution in the National Standard Guidelines established under the 

Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA). 

The bases to these summarizing comments and our recommendations to address them are the 

heart of this report. 

2. Harvest Management: An Evolving Discipline

The economic development associated with salmon fisheries and major impacts to salmon 

populations significantly preceded the knowledge necessary to manage the Pacific salmon 

resource effectively. In the Columbia River, significant fisheries by non-Native peoples began 

about 150 years ago and expanded very rapidly. Salmon hatcheries were initiated about 130 

years ago, and developmental or anthropogenic impacts (e.g., logging dams, agriculture) on 

salmon habitat were already being noted 100 years ago. By the 1920s, ocean troll fisheries were 

well established coastwide and were harvesting large numbers of Columbia River salmon. While 

some knowledge of salmon biology began in the early 1900’s, the establishment of a “modern” 

management paradigm came much later. For example: 

• the first scientific meeting on salmon homing and “stocks” occurred in 1939 (Mouton 

1939), and evidence of locally adapted salmon populations and the “Stock concept” was 

published in 1972 (Ricker 1972); 

• the introductory papers on production dynamics of Pacific salmon were published in 

1954 and 1958 (Ricker 1954, 1958); and 

• an ability to assess populations of Chinook and coho salmon followed development of the 

coded-wire tag in the early 1960s (Jefferts et al. 1963) and establishment of a coastwide 

tag recovery program in 1975. 

Unfortunately, by the time an empirical basis for salmon management was developed, overfishing had occurred for many years, habitats had been destroyed, and competitive fishing 

pressure between nations and user groups was commonly blamed for the declines in salmon 

abundance. Conservation sacrifices were usually left to the peoples fishing in-river ... the last 

folks in line for the returning salmon. 

In hindsight, the period before the 1930’s might be considered the era of blissful ignorance. A 

fish was a fish, the supply was abundant and could be supplemented by hatcheries, and, when 

3 
ISAB 2005-4 Harvest Report 

there were attempts to increase regulations in rivers, the fishers simply proceeded out into the 

ocean. Unfortunately, these ocean fisheries soon became highly competitive, and harvest in any 

one ocean region (management jurisdiction) intercepted salmon bound for other regions of the 

coast (Figure 1). The controversy over the ocean harvest of Chinook salmon continues today, but 

has been controlled through the 1985 Pacific Salmon Treaty (www.psc.org). 

Figure 1. Trends in the 

ported catches of Chinook

sh

.

t.

ow

he period between the 1930’s and 1970 could then be referred to as the era of limited 

nlightenment. Although a number of theories important to management began to emerge, 

panded

bia 

egislation slowly led

the demonstration of excessive fishing pressure and the need for improved coordination of 

o

 models 

0.0

0.5

1.0

1.5

2.0

2.5

190519101915192019251930193519401945195019551960196519701975198019851990

Catch Year

Index value

Washington St. SE Alaska B.C.

re PST, 1985

salmon by ocean troll 

fisheries (1905-1990) in 

Washington State, Briti

Columbia, and SE Alaska

Trends are relative to the 

average catches between 

1946-1950 to account for 

differences in landing 

records and smoothed (3-p

moving averages) to sh

time trends more clearly. 

Historical data compiled by

B. Riddell. 

T

e

agencies lacked adequate information to implement them, production from hatcheries ex

significantly, and managers exercised limited restraint on fishing. In addition, in the Colum

River the construction of dams radically altered the salmons’ environment. 

After 1970, a combination of new information, judicial decisions, and new l

to

management agencies for effective conservation of specific Chinook and coho salmon stocks. 

The development of a coastwide coded-wire tag program involving agencies from California t

Alaska provided the fundamental data needed to monitor the distribution of Chinook and coho 

salmon, annual survival rates, and exploitation patterns in fisheries for specific tagged 

populations. The coded-wire tag program also provided the first estimates of stock composition

in ocean fisheries. These data were primary in the development of fishery management

for Chinook and coho salmon (in the Pacific Salmon Commission and the Pacific States Fishery

Council) and currently provide the technical basis for most harvest assessments. The era from

1970-2000 was characterized by the expansion of stock-specific management based on a greatly 

enhanced empirical basis for management and the development and application of computer 

models for assessments and management planning. 

4 
ISAB 2005-4 Harvest Report 

Even at the beginning of the 21st century, the controversy over how to conserve and rebuild 

The

ut the

a. Evolution of Three Key Concepts

almon management along the Pacific coast over the past 50 years has been based on three 

ese

concept ... that homing of salmonids to their natal stream allows for the 

of

ly to

2. l relationships relating the 

er 

f progeny

ge, was

3. umptions about ocean rearing capacity ... that the number of 

he original Stock concept emphasized phenotypic differences between populations, not the 

or

or many 

m

 

natural production of Chinook and coho salmon and especially the role of harvest continues.

debates are better informed and focused, but no easier to resolve. Groups of salmon in the 

Columbia River Basin are listed under the ESA, billions of dollars have been invested in 

recovery of listed-species, mixed-stock ocean fisheries persist, and hatchery production

continues to dominate production of Chinook, coho, and steelhead salmon in the Basin, b

long-term preservation of salmon remains tenuous. The ISAB has considered the role harvest 

management plays in salmon recovery within this historical background. 

2

S

prominent tenets, but in the past decade, these foundations have been profoundly shaken. Th

tenets included: 

1. the Stock 5

accumulation of genetic differences between local populations and the development

adaptations to those environments. Local populations are more productive (progeny 

produced per female spawner) in their natal habitats and should be managed separate

maximize annual production and use of freshwater habitats. 

spawner-recruitment production relationships ... mathematica

numbers of fish that spawn in a year to the number of progeny produced from those 

adults. Theoretically, competition for space or food will limit the progeny produced p

adult at high population densities (density dependence). Consequently, at some

intermediate level of spawning abundance, the difference between the number o

produced and the number of animals needed to replace those spawners will be 

maximized. This number of spawners defined a management goal that, on avera

expected to produce a maximum sustainable yield (MSY) or harvest, given existing 

environmental conditions. 

hatchery production and ass

juveniles reared largely determined the adult return, and that production from hatcheries 

can increase harvest and mitigate for habitat loss. Ocean conditions were not believed to 

limit production because the production of salmon had been much greater historically. 

T

genetic processes that provided the rich diversity observed in salmonids. If no morphological

behavioral difference could be identified between spawning populations, then populations were 

aggregated into larger, more identifiable units for management. Production from these 

aggregated, natural populations mixed with an expanding production from hatcheries. F

years, the MSY management paradigm was superficially interpreted as sustaining high catch 

levels. People now recognize that these catches were based on the larger or more productive 

natural populations plus the hatcheries and that they masked the loss of diversity embodied in

smaller or less productive populations. Management focused on maintaining economic gain fro

these large population aggregates, while diversity within “stocks” was seldom considered. As the 

impact of these “mixed-stock” fisheries and the large scale of hatchery production were 

5

 Formalized for salmon at the 1939 meeting of the American Association for the Advancement of Science. 

5 
ISAB 2005-4 Harvest Report 

recognized, some managers began to question how sustainable this paradigm actually wa

Finally, over the past decade, the full force of how the ocean can limit salmonid production

became evident. Inter-annual variation in ocean conditions can severely limit salmon produc

and shifts in ocean conditions can be sudden. 

s.

tion,

oupled with these insights has been a growing realization of the uncertainty inherent in 

ific

tain

an

ncertainty in salmon management and assessment is significant and unavoidable. Pacific 

nd

ged:

b. Environmental Uncertainty

nvironmental uncertainty accounts for variation in production due to climate variability or

global

past,

itions

he extent of annual changes in marine survival of Chinook, coho, and steelhead salmon has 

of

ed an

lborn

C

managing Pacific salmonids. Unfortunately, the history of salmon management on the Pac

coast has not been to account for or acknowledge uncertainty, but has been to rely on over 

simplified concepts and attempt to maximize yield from the large stocks and hatcheries, sus

high exploitation rates to meet user demands, and defer management actions due to uncertainty. 

Uncertainty has frequently allowed one user group to blame another for declines in salmon 

abundance or an agency to delay conservation actions simply because of inability to “prove”

impact of a fishery or some other development action. 

U

salmon have a complex life cycle involving freshwater streams, anadromous migrations to a

from the ocean environments, and vulnerability to numerous forms of mortality, including 

fisheries, during their life span. Typically, three major sources of uncertainty are acknowled

environmental, production analyses and data, and management error. In practice though, it can 

be difficult to partition uncertainty among these sources. 

2

E

chance events in the rearing or migratory habitats. Although assessment models frequently 

generate an estimate of this uncertainty, they typically assume that the variability is random

between years and that the background environmental conditions have been stable over time. 

Clearly, these are simplifying assumptions and are increasingly inappropriate over time, 

particularly in light of recent evidence for changes in ocean productivity and concerns for

climate change. Predictions of future production or scenarios for salmon recovery require 

assumptions about future environments. If the future is not represented by conditions in the

then these predictions have substantially greater uncertainty associated with them. These 

concerns become increasingly complicated when forecasts involve trends in average cond

and changes in the extent of annual variability associated with climate and/or habitat changes 

(for example see Ratner et al. 1997, Lawson et al. 2004, Beamish et al. 2004). 

T

been tracked since the early 1970s using small coded-wire tags that are imbedded in the snout

juveniles and subsequently recovered in fisheries and spawning areas (tagging program

described by Jefferts et al. 1963, Johnson 1990). Coronado and Hilborn (1998a,b) provid

extensive review of these tagging programs over time and by geographic area. The results 

presented in Figure 2 are for representative Columbia River coho groups to demonstrate the

annual variations in survival and synchrony between them over time. These data have been 

updated from Coronado and Hilborn 1998a through recoveries in 2000 (data provided by Hi

and Magnusson, Univ. Wash., pers. comm.). The magnitude of the between-year variation is 

6 
ISAB 2005-4 Harvest Report 

substantial, with coho survival rates for individual groups varying from less than 0.25% to over 

8%. It is also immediately evident that survival rates may change significantly and very rapidly. 

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

6.0%

7.0%

8.0%

9.0%

19711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996

Col. R. mouth Col. Lower Tribs.

Willamette R Bonneville

Coho Salmon

Figure 2. Estimated smolt-to-adult survival rates for coho salmon released from hatcheries in 

the Columbia Basin by brood year (1971-1996, adult return years 1974-1999). Releases within 

each of these four groups are averaged within brood years. Data provided by R. Hilborn and A. 

Magnusson, updated analyses from Coronado and Hilborn (1998a,b).

2c. Uncertainty in Production Assessment 

Uncertainty in production assessment by populations (or aggregates of them in a production unit) 

and necessary data involve both errors in the data collected for the assessment and uncertainty in 

the estimation of population dynamic parameters. Assessment of a population consists of the 

determination of its production dynamics (rate of expected production, life history mortality, 

maturation rates, etc.) and management goals (desired number of spawners, sustainable 

exploitation rates, etc.) based on historical data. To determine these parameters adequately 

requires a history of data (catch, numbers of spawners, age classes, and environmental 

conditions) and usually involves a number of simplifying assumptions concerning error in the 

data and trends in environmental conditions. In practice, though, error in the data has seldom

been estimated or fully accounted for in estimation of model parameters. 

As an example of the uncertainties in data applied to “stock” assessment, Figure 3 presents the 

data for the combined Hanford Reach and Yakima production of Up-River Bright fall Chinook 

(URB), plus URB above Priest Rapids Dam (spawning years 1964-1991). The data series was fit 

to a Ricker recruitment function (adjusted for autocorrelation), as described by WDFW (2003, 

Table 9 and Figure 27). This example was not selected to be representative of all Chinook 

recruitment curves. The purpose of its presentation was to demonstrate the inter-annual 

variability in the adult returns (recruits) that may be expected from any number of spawning 

adults. At the estimated spawning target (~43,000 spawners), the range in observed recruitment 

7 
ISAB 2005-4 Harvest Report 

has been about twenty fold. It should also be noted that the variability in Figure 3 involves more 

sources of uncertainty than presented in Figure 2. Figure 3 relates the estimated number of adults 

spawning to the estimated number of progeny that become vulnerable to fishing and 

subsequently return as mature adults. Was the variation in recruits due to annual differences in 

spawning success or due to marine survival variation as presented in Figure 2? In many other 

populations, significant uncertainty exists in estimates of the parental spawning numbers (in 

most early spawner-recruitment models the number of spawning parents was assumed to be 

known without error). Knowing when and where the uncertainty is greatest (parental spawners, 

juvenile survival, or accounting for catch, etc.) is critical to correctly interpreting historical data 

and responding appropriately. 

0 50000 100000 150000

Spawners

0

260000

520000

780000

1040000

1300000

Recrui st

0 50000 100000 150000

0

260000

520000

780000

1040000

1300000

Figure 3. Combined Hanford Reach and Yakima production of Up-River Bright fall Chinook 

(URB), plus URBs above Priest Rapids Dam (spawning years 1964-1991). Data series with fitted 

Ricker line (adjusted for autocorrelation) from WDFW (2003).

2d. Uncertainty in Management Control 

A source of uncertainty that is frequently overlooked is management control of fisheries. If an 

escapement goal (the desired number of spawners) could be defined for each salmon population, 

such an objective would presume that management could regulate multiple fisheries to achieve 

these goals. With few exceptions, however, such management control is unrealistic. Most 

fisheries simultaneously exploit a mixture of salmon populations, and the catch from each is 

usually unknown. Several sources of error interact during the in-season management of a fishery: 

variation in the return abundance from the pre-season forecast; changes in return timing; 

variation in the response of fishermen to opportunities and/or weather. In practice, our ability to 

achieve a specific management target may be much less than acknowledged. 

8 
ISAB 2005-4 Harvest Report 

Finally, past management institutions and conflicts have shaped the current management 

environment. Because Morishima and Henry (2000) have provided an excellent historical 

perspective, this report will not address those issues. Although Morishima and Henry’s paper is 

focused on ocean salmon fisheries through the late 1990s, more recent data may be acquired to 

up-date that report from the Pacific Fisheries Management Council 

(www.pcouncil.org/index.html). In addition, regulatory histories (plus catch and escapements) 

within the Columbia River may be acquired from the Status Reports, Columbia River Fish Runs 

and Fisheries 1938-2000 (www.dfw.state.or.us/OSCRP/CRM/reports.html). 

For a succinct summary on ESA listings, recovery planning, and the biological opinions prepared 

to-date, see the Pacific Fisheries Management Council Pre-Season III Report’s Appendix A 

(www.pcouncil.org/salmon/salpreIII05/appdxa.pdf). 

3. Current Institutional Structure for Harvest Management Decision Making 

In many respects, the contours of the decision process for managing the harvest of Pacific 

salmon are dictated by the biological characteristics of the resource. Individual populations are 

characterized by high interannual variability in abundance and productivity. Because of their 

migratory nature, individual salmon populations are often subjected to harvest decisions made by 

many different jurisdictions. Most importantly, salmon are semelparous species, that is, they die 

after spawning, with high homing fidelity to return to their places of origin. Reproductive 

potential for the next generation is confined to annual spawning escapements of actively 

migrating mature fish that enter the rivers in concentrated numbers during short time frames. 

Fundamentally, harvest management involves decisions that reflect two elements: (1) 

information regarding the status of the resource and its productive capacity; and (2) a socially 

determined balance between preservation and utilization of the populations to be harvested, as 

well as the resources that affect their productivity, such as the quality and quantity of water and 

spawning/rearing habitat. The decisions made by individual jurisdictions on matters pertaining to 

harvest, production, and habitat protection respond to the needs of their own constituencies 

within the constraints of applicable law (see discussion of legal requirements below). 

For salmon originating in the Columbia River system, harvest management decisions are made 

by many different entities in both domestic and international forums. No single entity has the 

authority and responsibility for ensuring that management objectives are met for a given 

population, though in principle one entity, NOAA Fisheries, has the authority and responsibility 

for ensuring that recovery objectives are met for ESUs listed under the ESA. Consequently, 

cooperation and coordination is required across management jurisdictions. The complexities of 

harvest management decisions are specific to a salmon population depending upon the pattern of 

harvest. For example, harvest management of species like chum, sockeye, or steelhead is 

performed almost exclusively by managers with jurisdiction over in-river fisheries. In contrast, 

harvest management of Snake River fall Chinook involves in-river managers and ocean fishery 

managers from California to Alaska. The figure below (Figure 4) illustrates the necessity to 

coordinate harvest impacts of various jurisdictions that affect Columbia River Upriver Bright 

Fall Chinook. During 1979-1982 (a “base” period employed by the Pacific Salmon 

9 
ISAB 2005-4 Harvest Report 

10 

Commission), fisheries in Washington, Oregon, and the Columbia River (SUS) accounted for 

11% of the total fishing mortality of these Chinook, while the majority of the harvest occurred in 

Canada and Alaska. Although spawning escapement was 53% of the adult production, the 

number of spawning adults was chronically depressed. The need for a coastwide program aimed 

at rebuilding of the Upriver Bright and other depressed Chinook stocks became a primary focus 

for the deliberations that ultimately led to agreement on the 1985 Pacific Salmon Treaty between 

the United States and Canada. 

The time frame for decision making involving harvest management can range from several years 

for international agreements, like those negotiated by the Pacific Salmon Commission (PSC) to 

just a few hours for in-season management actions, such as opening or closing a fishery. 

Typically, harvest management planning decisions are made on an annual cycle coinciding with 

the availability of information on the status of individual populations and domestic fishery 

planning process. For Columbia River Chinook and coho salmon, this annual cycle occurs during 

a two-month period (March-April) when preseason planning processes relating to the Pacific 

Fishery Management Council (PFMC) are completed. 

1979-82 Distribution of Total Fishing Mortalities 

for Columbia River Upriver Bright Fall Chinook

Source: CTCHINOOK(04)-4

17%

19%

11%

53%

SEAK

Canada

SUS

Esc

Figure 4. Distribution of total fishing mortality for Columbia River Upriver Bright Fall Chinook 

(URB). Average annual distribution (1979-82 brood years) of total fishing mortalities, data are 

expressed as a proportion of the total production, including fishing mortality and spawning 

escapements. Data from Chinook Technical Committee of the Pacific Salmon Commission 

(CTCHINOOK(04)-4, 2004) at www.psc.org/publications.htm; SEAK = Southeast Alaska all 

gears, Canada = all ocean fisheries in BC, and SUS = all salmon fishing gears in Washington 

and Oregon, ocean and in-river fisheries. 

The annual harvest management planning cycle and in-season decisions are based on information 

that becomes available at different times. For the PFMC, preseason planning for coho and 

Chinook salmon is based on abundance forecasts that become available from state and tribal comanagers in mid-February. These forecasts are incorporated into planning models employed by 

the PSC and the PFMC. The PSC Chinook Model is used to develop estimates of abundance 

indices that determine the allowable level of impact under the PSC’s abundance-based 

management regimes for Canadian and Alaskan fisheries. These expectations are integrated into 

the PFMC’s Chinook FRAM (Fishery Regulatory Assessment Model) for preseason planning of 
ISAB 2005-4 Harvest Report 

Chinook fisheries south of the Canada/Washington border. For coho, the PSC and PFMC employ 

the same model, Coho FRAM. The PFMC’s FRAMs are made available to agency staffs and 

various constituency groups as well as the PFMC’s Salmon Technical Team (STT) to evaluate 

the impacts of proposed regulatory packages. For Columbia River Chinooks, outputs from the 

PFMC’s planning models are incorporated as inputs to in-river models for management planning 

and negotiation of annual fishing agreements. In April, a full package of agreements for ocean 

and in-river fisheries that affect Columbia River fall Chinook and coho is developed. 

The PFMC adopts recommendations for ocean salmon fishery regulations in April. Ocean 

fisheries are implemented starting in May. As ocean fisheries are conducted, catch monitoring 

and sampling programs provide data that are used to evaluate the need for actions to ensure 

compliance with adopted regulations. 

After individual populations are subjected to ocean commercial troll and recreational fisheries, 

maturing fish return to inside waters and rivers on their spawning migrations where they are 

commonly subjected to a series of commercial and recreational fisheries. Ultimately, fish 

surviving harvest by fisheries and in-river mortalities resulting from factors such as dam passage, 

surviving fish reach the spawning grounds. The timeline for harvest management decisionmaking affecting Columbia River salmon is presented in Table 1. 

Because of these biological characteristics and multi-jurisdictional, socially driven harvest 

decision processes, harvest management of salmon can be an extraordinary challenge. To 

effectively manage the resource, harvest management decisions of various jurisdictions 

throughout the migratory range of individual populations need to be coordinated, or at the very 

least, be compatible. This coordination is commonly accomplished through two means: (1) 

communication among scientists responsible for providing scientific advice to decision makers 

in key forums, and (2) formal agreements among relevant managers. 

3a. Many Managers, Many Challenges 

In-River (all species)

Tributary Fishery Managers. Harvest management decisions in tributaries of the Columbia 

River are made by tribal and state managers with primary jurisdiction over individual river 

systems. These decisions involve both planning and in-season management. Tributary 

managers include: 

Tribal Managers: Confederated Tribes of the Warm Springs Indian Reservation 

(CTWSIR); Confederated Tribes of the Umatilla Indian Reservation (CTUIR); Nez 

Perce Tribe (NPT); Confederated Tribes and Bands of the Yakama Nation (YIN); and 

the Shoshone-Bannock Tribes6

. 

 

6

 A May 1974 order of the Oregon District Federal court determined that tribes must have a meaningful role in fish 

management (Sohappy v. Smith, No. 68-409). See also Marsh, J.H. & James H. Johnson. 1985. The Role of Stevens 

Treaty Tribes in the Management of Anadromous Fish Runs in the Columbia Basin. Fisheries 10(4):2-5.

11 
ISAB 2005-4 Harvest Report 

State Managers: The State of Idaho (Idaho Department of Fish & Game, IDFG); the 

State of Oregon (Oregon Department of Fish & Wildlife, ODFW); and the State of 

Washington (Washington Department of Fish & Wildlife, WDFW) 

Agency staffs provide information on annual status and provide scientific advice for 

harvest management decisions within their respective jurisdictions. Constituencies of

each entity provide advice on socio-economic considerations.

Mainstem fishery managers. Harvest related decisions for planning and in-season 

management for mainstem fisheries of the Columbia River are made by tribal and state 

managers and by the Columbia River Compact. 

Tribal Managers: CTWSIR; CTUIR; NPT; YIN. The Columbia River Inter-Tribal Fish

Commission (CRITFC) coordinates tribal management and enforcement actions for 

tribal fisheries in Zone 6 (above Bonneville Dam). 

State Managers: ODFW and WDFW regulate Columbia River mainstem recreational 

fisheries. 

Tribal and State managers, together with the United States (NOAA Fisheries and 

USFWS) are in the process of developing a multi-year management agreement for 

salmon, steelhead, and sturgeon that originate in the upper Columbia River to set forth 

harvest management constraints and principles along with production plans and 

objectives. 

Scientific advice is provided by agency staffs. Constituencies of each entity provide 

advice on socio-economic considerations. 

Columbia River Compact (Compact): The Columbia River Compact was created by 

Congress in 19187

 and is charged by federal and state statutory authority to adopt seasons 

and rules for Columbia River commercial fisheries. Currently, the directors of ODFW

and WDFW (or their delegates) serve on the Compact, representing the Oregon Fish and 

Wildlife Commission (OFWC) and the Washington Fish and Wildlife Commission 

(WFWC). In addition, the Columbia River treaty tribes have authority to regulate treaty 

Indian fisheries, but tribal regulations are also approved by the Compact. 

Scientific advice to the Compact is provided by the Columbia River Technical Advisory 

Committee (TAC), comprised of representatives of state and tribal managers and federal 

agencies (NOAA Fisheries and USFWS). The TAC reviews forecasts of status, monitors 

 

7 Neither the State of Washington nor the State of Oregon had the jurisdictional authority to regulate fishing in the 

Columbia because the river itself formed much of the boundary between the two states. The Compact was 

authorized under state law in 1915 (RCW 75.40.010, 75.40.020; ORD 50-7.010, 507.030) and approved by

Congress in 1918. Article I, Section 10 of the U.S. Constitution provides that “no state shall, without the consent of 

Congress, enter into any agreement or compact with another state.” 

12 
ISAB 2005-4 Harvest Report 

abundance and fisheries in-season, and makes recommendations for harvest management 

to the Compact. 

Ocean fisheries (Chinook and coho)

Harvest management decisions affecting Columbia River salmon in ocean fisheries are made by 

tribal and state managers, Fisheries and Oceans Canada, and the U.S. Secretary of Commerce. 

Pacific Salmon Commission (PSC). The PSC was established pursuant to the 1985 Pacific 

Salmon Treaty between the United States and Canada. Except for sockeye and pink salmon 

returning to the Fraser River, the PSC has no regulatory or management authority of its own, 

but is empowered to develop fishery regimes or agreements that will govern the regulation of 

fisheries by the domestic managers of the U.S. and Canada. The PSC meets twice annually 

and is focused on development of long-term fishing regimes and matters of coordination and 

cooperation in salmon management between the United States and Canada. 

The primary PSC agreements affecting Columbia River salmon involve Chinook 

management and a general Pacific Salmon Treaty obligation not to initiate new intercepting 

fisheries (those that harvest fish produced in the rivers of the other country). Two types of 

fishing regimes are established by the current (1999) PSC agreement: (1) Aggregate 

Abundance Based Management (AABM) regimes constrain fishery harvest rates in response 

to projections for hatchery and natural production combined. AABM regimes apply to 

Southeast Alaskan (all gear), Northern British Columbia (sport and troll), and West Coast 

Vancouver Island (sport and troll) fishery complexes; (2) Individual Stock-Based 

Management (ISBM) regimes. All fisheries that are not managed under AABM regimes are 

managed under general obligations to reduce harvest rates relative to the 1979-1982 base 

period for individual stocks that are not projected to meet established spawning escapement 

goals. 

Bilateral Technical Committees provide scientific advice to the PSC. The terms of reference 

for the PSC Technical Committees require members to serve as independent advisors, not as 

advocates for agency positions. Information on socio-economic matters is largely provided 

by the PSC’s Northern and Southern Panels. 

Tribal Managers. Makah Indian Tribe; Quinault Indian Nation; Quileute Tribe; Hoh Tribe, 

S’Klallam Tribe. These tribes regulate treaty Indian troll fisheries under the umbrella ocean 

fishery regulations recommended by the Pacific Fishery Management Council and approved 

by the Secretary of Commerce. 

State Managers. ODFW, WDFW, Alaska Department of Fish & Game (ADFG) in state 

territorial waters inside three miles of the coastline. The Department of Fisheries and Oceans 

has the responsibility for regulating Canadian ocean fisheries. 

Secretary of Commerce. Under the Magnuson-Stevens Fishery Conservation and 

Management Act (MSFCMA) of 1976, the Secretary of Commerce has regulatory 

jurisdiction over fisheries in the Exclusive Economic Zone from 3-200 miles offshore. The 

13 
ISAB 2005-4 Harvest Report 

MSFCMA established eight regional fishery management councils. Two of these, the North 

Pacific Fishery Management Council (NPFMC) and Pacific Fishery Management Council 

(PFMC), are responsible for management of Pacific salmon. These Councils develop 

recommendations for ocean salmon fisheries and provide them to the Secretary for 

consideration. The NPFMC has deferred salmon management decisions to ADFG under 

provisions of the Pacific Salmon Treaty. The PFMC is comprised of representatives from the 

States of Washington, Oregon, California and Idaho, a tribal representative, and 

representatives of NOAA Fisheries and the US Fish & Wildlife Service. In addition, the 

NPFMC and PFMC include reciprocal non-voting representatives for coordination. Because 

of interactions between the PFMC and PSC, the PFMC is required to include at least one 

member who also serves on the PSC or the PSC Southern Panel. The PFMC considers 

recommendations of its advisory bodies and makes harvest management decisions through an 

annual planning process. 

The PFMC’s Salmon Technical Team (STT), comprised of scientists from State, Federal, and 

Tribal managers, is responsible for analyzing impacts of regulatory measures and providing 

scientific advice, both in preseason planning processes and for in-season management

actions. Members of the STT serve as independent advisors and not as advocates for the 

entities they represent. Because of the need for close coordination, there is considerable 

overlap between the members of the STT and the PSC’s Chinook and Coho Technical 

Committees. The principal focus of the joint PSC-PFMC planning process is on 

incorporating annual information on the status of salmon populations and the conduct of 

fisheries into the calibration of fishery planning models used to evaluate the impacts of

harvest management measures on individual populations. The PFMC’s Scientific and 

Statistical Committee (SSC) is comprised of independent scientists with various disciplines 

and is responsible for reviewing methodologies such as models, their parameterizations, and 

abundance forecasting procedures. 

North of Cape Falcon Forum: The PFMC uses Cape Falcon, Oregon as the southern 

management boundary for Columbia River Chinook and to implement harvest allocation 

schedules for non-Indian commercial and recreational fisheries off the coasts of 

Washington and Oregon (PFMC Pacific Coast Salmon Plan, Section 6.1). For coho, the 

vast majority of ocean fishery impacts of Washington coastal and Puget Sound coho 

usually occur in the area north of Cape Falcon. The North of Cape Falcon 

Forum, sponsored by state and tribal co-managers, convenes the co-managers and 

representatives of the commercial and recreational fishing sectors during the Council’s 

preseason planning process to determine allocation and conservation recommendations 

for fisheries north of Cape Falcon (PFMC Preseason Report I, Appendix C). 

Advice on socio-economic considerations is provided by the Salmon Advisory Sub-Panel 

(SAS) and obtained through public hearing processes. The SAS consists of representatives 

from various sectors (e.g., commercial, recreational, general public) and is responsible for 

providing recommendations for fishery regulations. 

14 
ISAB 2005-4 Harvest Report 

Enforcement advice is provided by state and federal fisheries enforcement staff. Legal 

counsel from NOAA Fisheries attends all PFMC meetings to provide advice regarding the 

consistency of PFMC actions with requirements of applicable law. 

The PFMC employs an intensive preseason fishery management planning process during 

March-April each year. Ocean fisheries are managed under the provisions of a long-term 

Salmon Fishery Management Plan that identifies conservation objectives for individual 

stocks and allocation requirements between non-Indian fishery sectors. As part of the annual 

planning process, agreements are made between state and tribal co-managers to govern 

fisheries inside state territorial waters, to equitably distribute the conservation responsibility 

and allowable fishery impacts, and to coordinate harvest measures to meet resource 

management objectives for individual stocks. 

3b. Legal Requirements for Harvest Management

Harvest management decisions must comply with applicable law. For salmon, this law includes 

Indian treaties, agreements of the PSC and obligations under the Pacific Salmon Treaty between 

the United States and Canada, federal statutes such as the MSFCMA, the National 

Environmental Policy Act (NEPA), and Endangered Species Act, domestic and state statutes, 

and applicable case law. Requirements of four areas of law with special significance to harvest 

management are highlighted below: 

Indian Treaty fishing rights. Through treaties with the United States, Indian tribes reserved 

the right to take fish at their usual and accustomed places. Those places are determined by 

the federal courts for individual treaty tribe. The courts have determined that treaties entitle 

tribes to 50% of the harvestable surplus of fish originating in or passing through their usual 

and accustomed fishing places, prevent laws from being enacted that discriminate against 

tribal fishing, and restrict the capacity of non-Indian governments to regulate Indian fishing 

except when necessary for resource conservation.

8

 The term “conservation” has a specific 

legal meaning when applied in the context of treaty fishing; rather than “wise use” 

connotations of conservation, the courts have ruled that conservation actions must be 

reasonable and necessary for the perpetuation of a species of fish. To have the largest 

possible sustained harvest, state, tribal, and federal fishery managers generally rely upon the 

concept of Maximum Sustained Yield as a standard for regulation of their fisheries. 

Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA). In addition to 

the institutional structures of regional councils, the MSFCMA sets forth a set of national 

standards that must be attained for ocean salmon fishery management: 

1. Conservation and management measures shall prevent overfishing while achieving on a 

continuing basis, the optimum yield from each fishery for the United States fishing 

industry. 

 

8

 Sohappy v. Smith (302 F.Supp. 899 (1960)) was the first in a series of cases dealing with treaty-protected Indian

fishing rights in the Columbia River. Harvest sharing and tribal participation in management were addressed in 

Sohappy decisions No. 68-409 dated May 8, 1974 and Aug 20, 1975. 

15 
ISAB 2005-4 Harvest Report 

2. Conservation and management measures shall be based upon the best scientific 

information available. 

3. To the extent practicable, an individual stock of fish shall be managed as a unit 

throughout its range, and interrelated stocks of fish shall be managed as a unit or in close 

coordination. 

4. Conservation and management measures shall not discriminate between residents of 

different States. If it becomes necessary to allocate or assign fishing privileges among 

various United States fishermen, such allocation shall be

a. fair and equitable to all such fishermen; 

b. reasonably calculated to promote conservation; and 

c. carried out in such manner that no particular individual, corporation, or other entity 

acquires an excessive share of such privileges. 

5. Conservation and management measures shall, where practicable, consider efficiency in 

the utilization of fishery resources; except that no such measure shall have economic 

allocation as its sole purpose. 

6. Conservation and management measures shall take into account and allow for variations 

among, and contingencies in, fisheries, fishery resources, and catches. 

7. Conservation and management measures shall, where practicable, minimize costs and 

avoid unnecessary duplication. 

8. Conservation and management measures shall, consistent with the conservation 

requirements of the Act (including the prevention of overfishing and rebuilding of 

overfished stock), take into account the importance of fishery resources to fishing 

communities in order to: 

a. provide for the sustained participation of such communities, and 

b. to the extent practicable, minimize adverse economic impacts on such communities. 

9. Conservation and management measures shall, to the extent practicable, 

a. minimize bycatch and

b. to the extent bycatch cannot be avoided, minimize the mortality of such bycatch. 

10. Conservation and management measures shall, to the extent practicable, promote the 

safety of human life at sea. 

The PFMC has established operational guidelines (National Standard 1) to prevent overfishing 

and achieve optimum yield (OY). Optimum yield emerged as a management concept about a 

decade before the passage of the MSFCMA and was included in the Law of the Sea Treaty. Early 

in its deliberations, the PFMC determined that optimum yield determinations should start from a 

fixed reference point - maximum sustained yield, and then be modified in response to social and 

economic considerations. 

 

16 
ISAB 2005-4 Harvest Report 

Currently, NOAA Fisheries describes optimum yield as: 

 

"NOAA Fisheries is charged with managing fisheries to provide the greatest overall 

benefit to the Nation, particularly with respect to food production and recreational 

opportunities, while taking into account the protection of marine species and ecosystems. 

We accomplish this through management, to achieve, on a continuing basis, the optimum 

yield from each fishery. Optimum yield is defined as the amount of fish which will achieve 

the maximum sustainable yield, as reduced by any relevant economic, social, or 

ecological factor. In the case of an overfished fishery, optimum yield has been defined as 

that amount of fish which will provide for rebuilding of the stock to a level which will 

support the maximum sustainable yield. 

Our management decisions must reflect the needs of many different groups, including 

commercial and recreational fishermen, fishing communities, non-consumptive users, 

Pacific Islanders, and Native American tribes which have treaties with the United States 

guaranteeing certain fishing rights which we are obligated to uphold. We must also 

consider efficiency, minimize costs, avoid unnecessary waste and duplication, and 

allocate harvest restrictions and recovery benefits fairly among all users, while 

minimizing adverse economic impacts on fishing communities, consistent with our 

conservation objectives. To achieve this, we will focus on reducing sources of waste such 

as overcapitalization and bycatch (all fish harvested but not sold or kept for personal 

use, including economic and regulatory discards), mitigating the effects of fishery 

management on fishing communities, and increasing recreational fishing opportunities."

The PFMC is required to adhere to requirements of fishing regimes established by the PSC 

and abide by federal decision-making requirements set forth in statutes such as NEPA. 

The Endangered Species Act (ESA). Numerous salmon populations from the Columbia River 

have been listed as threatened or endangered under the ESA. Harvest management actions 

that impact these populations are subject to consultations with NOAA Fisheries (for 

anadromous forms) and the USFWS (for resident forms). Harvest management decisions 

affecting ESA-listed populations must meet a “no jeopardy” requirement of the legislation. 

The assessment of whether a harvest action will cause “jeopardy” is documented in a 

“biological opinion” by the responsible agency, and annual guidance letters advise harvest 

managers how to comply in their implementation. An assessment of the PFMC’s 

recommended fishery regulations with respect to these standards is provided to the Secretary 

of Commerce as part of the record of decision for proposed harvest management measures. 

Columbia River Compact. The Compact must consider the effect of commercial fishing for 

salmon, steelhead, and sturgeon in the Columbia River on escapement, treaty rights, and 

sport fisheries, as well as the impact on species listed under the Endangered Species Act 

(ESA). Although the Compact has no authority to adopt sport fishing seasons or rules, it is an 

inherent responsibility of the Compact to address the allocation of limited resources among 

users. 

17 
ISAB 2005-4 Harvest Report 

3c. The Decision-Making Process 

The annual harvest management process centers around attaining management objectives for 

individual populations of fish, usually centered on constraining exploitation rates on maturing 

and mature fish so as to attain desired levels of spawning escapements. Consequently, the 

following description of harvest management processes will start with ocean fisheries and end 

with in-river fisheries. A schematic diagram of the process (Figure 5) and time schedule of 

annual fishery management planning processes (Table 1) follows. 

Pacific Salmon

Commission

North Pacific

Fishery

Management

Council

Pacific Fishery Management Council

State & Tribal Management

Agreements

North of Falcon

Process

In-River

Management

Manager to Manager

information

exchange with

Canada

State-Tribal

staff input

Terminalrun information, abundance forecasts

Abundance,

fishery

expectaions

Figure 5. Harvest Management of Columbia Up-River Fall Chinook 

18 
ISAB 2005-4 Harvest Report 

Table 1. Annual timeline for harvest management decisions affecting Columbia River salmon. 

1. A. Decision timeline for Chinook salmon significantly impacted by ocean fisheries. For coho, PSC 

and NPFMC not relevant. 

Entities and Timeline Scientific Advice Socio-Economic Advice 

Pacific Salmon 

Commission, Chinook 

Technical Committee 

(CTC) 

Provided by Bilateral Technical Committees. 

Evaluation of regime performance 

Annual calibration of CTC Model

Post season review 

Regime development reflected in

negotiated long-term agreements. 

North Pacific Fishery 

Management Council

Defers to PSC and ADFG Alaska Board of Fish 

Pacific Fishery

Management Council

January 

Mid-February

Mid-March

April 

May 

May through following

April 

Nov 

Scientific & Statistical Team reviews models and

methodologies.

Salmon Technical Team (STT) prepares post season review

State & tribal co-managers provide abundance forecasts. 

STT prepares preseason report on abundance expectations

and parameterizes planning models, including projected 

impacts of Canadian and Alaskan fisheries driven by

AABM regimes. 

STT evaluates regulatory packages (in consultation with

state & tribal co-managers) in relation to Council objectives 

and legal requirements; prepares preseason report II for 

public comment. 

PSC manager-manager discussions with Canada to obtain

preseason expectations of abundance and fisheries. 

STT evaluates modifications to options and prepares preseason report III describing expected impacts in relation to 

PFMC management objectives, documents technical basis 

for decisions (models & methods) reports. 

PFMC staff prepares NEPA analysis and submit to

Secretary of Commerce for consideration. 

State & Tribal co-managers monitor fishery and sample 

fisheries (size, coded-wire-tags, scales, etc.), PFMC and 

STT take in-season action as necessary and appropriate for 

compliance with fishery regulations. 

PFMC’s Scientific & Statistical Committee and Salmon

Technical Team review planning, models, forecasts, and 

analysis methods as necessary and appropriate. 

Framework Plan requirements 

Salmon Advisory Subcommittee 

(SAS) provides recommendations

on season structure. 

Public comment 

PFMC establishes specific 

management objectives &

guidance to STT, identifies options 

for public review. 

Constituency and co-manager 

meetings (North of Falcon process) 

PFMC revises options in response 

to input, receives advice from SAS 

& public comment. 

State & tribal co-managers agree 

on preseason fishing plans for 

ocean and inside fisheries. 

PFMC adopts recommendations

for seasons & regulations. 

NEPA statements prepared. 

Secretary of Commerce evaluates 

(dis)approves.

In-season conference calls 

involving STT, state and tribal 

managers, SAS. 

19 
ISAB 2005-4 Harvest Report 

1.B. Decision timeline for all species.

Entities and Timeline Scientific Advice Socio-Economic Advice 

In-River Management

Early Dec 

Mid-Dec 

Jan 

Feb 

Feb-May 

Early July 

Aug-Sept

Mid-Sept

State & tribal staffs monitor run sizes and catches in-season. 

Columbia River Technical Advisory Committee (TAC) provides

analysis and advice to Compact. 

Meeting and information exchange schedules for the Production 

Advisory and Policy Committees. 

Columbia River staffs provide estimates of escapements and run 

sizes according to the following schedule. 

Winter season report on sturgeon and smelt management. 

Post-season reconstruction and preseason run forecasts for spring & 

summer Chinook and sockeye. 

Status report on spring Chinook and steelhead. Preliminary postseason fall fishing report. 

Status report Snake River fall Chinook. Run size forecasts for fall 

Chinook. Columbia River staffs provide preseason abundance 

forecasts to STT and PSC Technical Committees. 

In-season management of fall fishery.

Fall season report. 

Post season spring/summer fishing report. 

Columbia River Compact 

establishes seasons. 

20 
ISAB 2005-4 Harvest Report 

3d. The Task Today 

Salmon management in the Columbia River is currently dominated by conservation objectives 

and by the requirements of the Endangered Species Act. Salmon management today faces an 

increasingly challenging set of constraints and contrasting objectives. For example, while several 

ESUs are listed under the ESA, mixed-stock ocean fisheries (which incidentally harvest some

fish from listed ESUs) continue and managers must respect Treaty fishing rights. While the 

debate concerning the interactions of hatchery-produced fish and naturally produced fish has 

never been more acrimonious, hatchery production continues and new means to identify these 

fish for harvest are being implemented (mass-mark selective fisheries requiring the release of unmarked and usually naturally produced salmonids). Ultimately harvest increases the demand for 

hatchery production, which in turn may have other negative effects on wild populations (see the 

ISAB supplementation report, ISAB 2003-3). Although incidental mortalities relative to landed, 

reported catches have increased in many fisheries, increasing the uncertainty about harvest 

impacts, precautionary approaches are also being promoted in management guidelines that 

require reductions of fishing impacts to compensate for this greater uncertainty. Under the ESA, 

jeopardy determinations are made at the level of the ESU (usually an aggregate of spawning 

populations), and harvest management typically operates on aggregates of independent 

populations. Salmon production and allowable harvest rates, however, are determined by the 

dynamics of each local salmon population in their habitats, and should be managed for their 

individual characteristics. 

The ISAB has attempted to integrate the above discussion of institutional structures for salmon 

management with the biological basis for production and establishment of management targets 

(Figure 6). A fundamental issue for salmon management has been the challenge of determining 

biological productivity (rate of production of mature progeny per spawning female) of each 

population unit (a demographically independent spawning group) and then controlling harvest 

impacts to achieve the management objectives for those units. The problems in achieving this 

include: 

• inadequacy of data to identify the independent population units and estimate their 

individual productivity; 

• inherent differences in productivity due to differences in natural habitats and changes in 

habitat conditions over time; 

• practical inability to control the cumulative impact of multiple fisheries on each 

population unit; and 

• high degrees of uncertainty during in-season management processes, and unpredictable 

changes in environmental conditions through time. 

Although the problems associated with multiple units with different “productivity” and multiple 

fisheries have been recognized for many years (Ricker 1958), in practice, they have seldom been 

fully addressed in salmon management. The mixing of hatchery-produced salmon with natural 

salmon is an extension of this basic problem, but one that greatly increases the risk of overfishing on natural populations. The upper portion of Figure 6 portrays the problem of 

aggregating multiple population units into “management units” and the establishment of

management objectives for these aggregates. The remainder of Figure 6 encapsulates the 

institutional details presented above as well as the extensive data required for annual evaluation 

21 
ISAB 2005-4 Harvest Report 

of fishing impacts and the status of the management units. These data must then be integrated 

with spawning surveys and biological sampling within population units to estimate abundance, 

productivity, and the spatial distribution of salmon within the management unit. 

Each element of Figure 6 may differ between species or sub-groups within a species (e.g., spring, 

summer, fall Chinook) but the major elements are generally representative of all Pacific salmon. 

There will, however, be differences between species in the roles of respective management 

institutions (e.g., varying role of ocean fisheries versus in-river fisheries). Attempting to describe 

these differences comprehensively would be a large task but it can be effectively illustrated by 

the major functions of harvest management using three examples of Columbia River Basin 

salmon runs of varying characteristics: 

1. a healthy natural population (Upriver Bright fall Chinook); 

2. an ESA-listed Chinook population impacted by ocean fisheries (Snake River fall 

Chinook); and 

3. an ESA-listed Chinook population that is not harvested significantly in ocean fisheries 

(spring Chinook). 

Tables for each example are provided in Appendix A. These tables identify a range of 

management functions, the responsible institutional entities, areas of responsibility, legal 

authorities, decision time frames, and relevant scientific issues and questions. 

22 
ISAB 2005-4 Harvest Report 

Figure 6. Schematic integrating population assessment and harvest management for Columbia River 

salmon, details presented for fall Chinook (details for other species may vary). HPU = Hatchery

Population Unit, IPU = Independent natural Population Unit. CWT = coded-wire tags. (Note: Examples 

of Institutional structure by Harvest Management Units are described in Appendix A.)

Harvest Management Unit 

(aggregate of IPU + HPU1 to x) 

IPU1

IPU2

... 

IPU10

HPU1

HPU2

HPUx 

Long-term management goals and data:

3⁄4 Determine spawning escapement goals

and sustainable mortality rates 

3⁄4 Acquired exploitation rate and

distribution indicator (tagged Unit)

3⁄4 Monitor biological traits: hatchery vs. 

wild, age structure, ... 

3⁄4 Determine non-harvest related

mortalities 

3⁄4 Establish clear management objectives 

and restoration plans where needed. 

Ocean Fisheries

(mixed stock,

multiple agencies); 

regulations are not 

stock specific. 

Mature

runs

Legal 

Constraints: 

ESA jeopardy

standards (listed 

stocks), National 

Standards (MSFCMA)

Treaty obligations

Ocean Fishery Management: 

1) Stock Specific includes PMFC, 

WA, OR, CA & Treaty Troll 

Tribes (‘Stock of Concern’) 

2) Non-Stock Specific (aggregate 

abundance indices) includes PSC 

(Alaska, BC, NPFMC) ... 

CHINOOK ONLY

In-River Fisheries

(fewer stocks & agencies):

Management may be stock 

specific by run-timing, 

location, coloration, size ...

Population assessment 

information: for each 

geographically separate unit 

(population) ... conduct annual

spawner enumerations, age 

structure, habitat assessments, & 

monitor environmental conditions; 

BUT total catch is usually 

unknown unless a Unit is tagged. 

Annual Status Assessment: 

IPUx ... annual spawning

escapement to determine trends by 

unit, but total catch is usually 

estimated for the aggregate Harvest 

Management Unit. Tagging provides 

some information by individual

population (usually hatchery) for 

survival rates, exploitation patterns 

and rate, etc. Incidental mortality is 

not known by Unit and can only be 

estimated. Plus, annual forecasts of

abundance, climate forecasts and 

impact considerations. 

Annual evaluation and postseason reviews 

Data acquired from fisheries and spawning escapement: 

Catches, incidental mortality, tag sampling and recovery, ages, 

dam counts and inter-dam losses, spawning surveys, biological 

data in catch and spawners. The partitioning of data by 

population units varies by fishery, sample sites, and years. 

Annual Harvest 

Management Planning

process ... (application of 

models, ecosystem

considerations, & use of 

control rules)

23 
ISAB 2005-4 Harvest Report 

4. ISAB Review

4a. Vision Statement 

This report focuses on the role that harvest management plays in the conservation and 

sustainable utilization of salmon from the Columbia River Basin. The terms conservation and 

sustainability are often each given different definitions that result in ambiguous descriptions. 

This may be expected, because each term involves biological and socio-economic factors. 

Diverse perspectives and values inevitably become involved such that the terms mean different 

things to different people. In the United States, political decision-making processes that are 

guided by a suite of legal mandates determine what is to be sustained, how, and at what cost. 

Decisions are usually made by governments with advice from constituencies who then decide if 

the consequences are acceptable. Since fish don't vote, they bear the consequences of human 

decisions. To be sure, the manner in which fisheries and other aquatic resources have been 

managed has been fertile ground for controversy. 

Within the context of this assignment, the ISAB’s vision of conservation and sustainable use is 

centered on decision processes that are necessary to ensure that the removal (i.e., total mortality 

from all sources) of Columbia River salmon does not exceed the productive capacities of 

naturally spawning populations over the long-term. From this perspective, effective harvest 

management systems must have three primary components: 

4. a sound scientific foundation for management; 

5. clearly defined priorities and objectives for resource conservation and fisheries 

management; and 

6. the capacity to constrain total fishing mortality on a population to a level that proves 

sustainable after accounting for all sources of mortality affecting the population 

throughout its life cycle. 

This report first describes these components and then (Section 4b.) comments on the adequacy of 

their status for the Columbia River Basin. 

Sound Scientific Foundation

Science must effectively inform decision making for harvest management. Science is involved in 

designing monitoring programs, collection of data, and the development and use of reliable 

methods of analysis to assess biological status of the populations and fishery impacts. These 

assessments frequently involve limited data, data that varies in quality though time, and “noisy” 

data from complex ecological and social systems. 

24 
ISAB 2005-4 Harvest Report 

A sound scientific basis for harvest management would: 

1. provide the best practically obtainable and pertinent data; 

2. provide the best available science9

 at the time decisions are made; and 

3. ensure transparency for the basis of advice, analyses, competent peer review, and a 

process for regular review and response (learning) as experience is gained. 

Given the uncertainties and unknowns that remain in salmon management and recovery, a 

priority should be placed on ensuring an empirical basis for assessing trends and status in each 

production unit and on obtaining key information required to control harvest impacts. Welldesigned monitoring programs are required to collect data on fisheries and escapements. A sound 

scientific basis for harvest management would inform decision-makers of the need for better 

information as harvest approaches the limits sustainable by the productive capacity of the 

resources and of the trade-offs between uncertainty and costs of management. Fishery and 

escapement data, biological data on the exploited populations, and basic data on production 

capacities are the fundamental building blocks of a sound scientific foundation for harvest 

management. These are necessary to: (a) identify and quantify mortality from all sources 

affecting a given population throughout its life cycle, (b) provide biological goals for 

management, and (c) provide clear early signals of non-sustainability should it occur. For 

example, the monitoring program should be capable of differentiating causes of a decreasing 

trend in spawning numbers; is it due to over-fishing, reduced productivity in freshwater, and/or a 

period of reduced ocean production? In the absence of adequate data, managers should reduce 

harvest impacts on the resource to ensure its continuance and productivity. 

Clearly Defined Management Objectives

Effective harvest management requires: 

1. definition of the production units10 to be managed; 

2. biological conservation targets for each production unit; and

3. objectives and priorities for fisheries and clearly defined risk tolerances. 

In spite of all of the data that have been collected on Pacific salmonids, the reality is that 

fisheries management is inexact. There are many sources of uncertainty. Ultimately, science 

must provide information and advice in the face of both risk and uncertainty. Risk can be 

minimized and options preserved in a dynamic and unstable environment by maintaining a 

genetically diverse mix of component populations and their habitats. In the absence of accurate 

information on productivity and exploitation for specific component populations, a sound harvest 

management decision process would employ a precautionary approach to protect a minimum 

spawning population size in each unit, given the current and potential future range of 

 

9

 The Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA) requires that harvest management

decisions use the “best available science.” National standards and guidelines have been developed and are being 

applied in decision-making processes of regional fishery management councils (see discussion of current

institutional structure). 10 Production unit in this discussion is a spatially defined group of salmon populations and hatcheries that are 

determined by the responsible agencies as a basis for conservation and management. 

25 
ISAB 2005-4 Harvest Report 

environmental conditions11 and the range of error between estimates and true values. 

Capacity to Constrain Total Fishing Mortality 

The capacity to constrain harvest of Columbia River salmon requires: 

1. consistent quality-assured data acquired for pre-season planning and in-season 

monitoring; 

2. clear management objectives and timely in-season decision processes; and 

3. management accountability. 

This capacity is determined by the institutions involved in regulating fisheries throughout the 

migratory ranges of individual production units. Because many jurisdictions typically affect the 

harvest of Columbia River salmon, fishery management decision processes must be sufficiently 

coordinated to collect consistent biological data and accomplish management objectives for 

production units of interest. The capacity to constrain harvests to levels sustainable by the 

inherent productivity of production units depends upon common acceptance of management 

objectives and responsibilities. It also depends upon having accountability in decision processes 

involving a variety of necessary components, including sound scientific information, stakeholder 

participation, and enforcement. Walters (1995) discusses institutional requirements for 

sustainability. The current institutional structure for managing Columbia River salmon is 

described and evaluated in reference to these requirements in Section 3 of this report. 

4b. Indicators of effective harvest management systems 

Indicators of performance of the harvest management system for Pacific salmon are derived from

these three requirements for effective management: sound scientific foundation, clearly defined 

objectives, and institutional capacity to constrain total fishing mortality. 

Performance Indicator 1: Is the Scientific Foundation sound?

Although Pacific salmon have been studied extensively, scientists and managers continue to 

learn about population structure, population processes and production dynamics, and about 

the extent of inherent variability in the environment as it affects natural populations. 

Generally, the scientific community knows less than is expected or understood by the public. 

The ISAB notes, however, that progress in science that supports harvest management is 

evident and likely to continue. The ISAB found the use of technical information in setting 

harvest limits to be incomplete, especially for biological opinions related to harvest impacts 

on ESA-listed species. 

The scientific basis for assessment and harvest management consists of empirical information, 

statistical analysis of that information, developing inferences, and providing sound advice for 

 

11

page 6, NW Region Sustainable Fisheries Division report (Dygert and Bishop 2004): “With respect to the 

abundance criterion, the VSP report provides guidelines for developing “viable” and “critical” abundance levels to 

serve as benchmarks for assessing the status of populations.” 

26 
ISAB 2005-4 Harvest Report 

the development of annual management plans, and recommending research. The empirical 

basis must: 

1. identify the spatial units or organization of salmon production and their habitats; 

2. provide the data necessary for assessment and planning; 

3. enable the determination of sustainable levels of use (includes all sources of 

anthropogenic related mortality) to ensure conservation;

4. provide for annual monitoring and assessment of the production units to enable 

documented annual advice on abundance trends, population status, and limits to be 

addressed in fishery management plans. 

Significant progress is being made in the delineation of production units for salmonids. The 

NOAA status reviews (www.nwfsc.noaa.gov/trt/brtrpt.htm) and the work of the Technical 

Recovery Teams (TRT, www.nwfsc.noaa.gov/trt/) have identified independent demographic 

units for salmon production. (See Background Section 7.a, Sustaining Diversity.) 

The empirical bases for assessment and for determining management goals in production units 

are data quality and availability, their use in analyses, and the inferences drawn from these 

analyses (e.g., spawning escapement goals and/or target exploitation rates). In essentially all 

cases for Pacific salmonids from the Columbia River Basin, the quality of historical data has 

severely limited its use for assessment of individual populations and estimation of production 

rates. 

Problems with the data include: 

• data were typically collected only after years of over-fishing; 

• the origin of the fish caught in each fishery is frequently unknown (and individual 

populations are usually caught in numerous fisheries); 

• the actual number of spawning fish to associate with catch is frequently unknown; and 

• the age of fish caught and/or spawning is seldom monitored annually.12

Unfortunately, these types of problems are quite common along the Pacific coast when agencies 

attempt to estimate production (progeny) from the number of adults (spawning abundance, stock) 

in the parental year (i.e., spawner/recruitment analyses as described by Ricker 1954 or BevertonHolt 1957; see Primer in Salmon Harvest Management, Section 7e). The problem was common 

enough that Hilborn and Walters (1992) concluded that: “We think that bad stock-recruitment 

analyses have been a significant factor leading to over-exploitation and stock collapse for some 

major fisheries.” (pg. 287)

Ironically, these limitations of historical data may not have been as serious a limitation in the 

Columbia River Basin as they may have been in less disturbed environments. The extensive 

alternations of habitat in the Columbia negate a basic assumption (a consistent habitat base) of 

stock/recruitment analyses and restrict where such analyses have proven somewhat informative 

(i.e., in Lewis River wild fall Chinook, Coweeman tule fall Chinook, and Hanford Reach Bright

fall Chinook). In most other Columbia production units, these data limitations have contributed 

to the difficulties in defining biologically based recovery goals and management targets. 

 

12 Similar comments and concerns were expressed by the ISAB during our Supplementation report, Chapters 3 and 4, ISAB 2003-03.

27 
ISAB 2005-4 Harvest Report 

Over the past decade, however, there has been notable attention to the scientific basis for 

recovery of depressed salmon abundance and for improving assessment and management. The 

ISAB notes particularly: 

• the inclusion of life history diversity in consideration of natural populations, the value of 

meta-population processes (i.e., maintain diverse inter-connected populations within 

freshwater habitats); 

• increased recognition of ecosystem values (see Background Section 7.b, Freshwater 

Ecosystems); 

• definition of criteria for viable salmon populations including threshold values to delimit 

viable (Box A2) and critical (Box A3) population abundances (McElhany et al. 2000); 

• means to assess viability of individual populations (McElhany et al. 2003); 

• attention to regional monitoring programs; and 

• the application of risk assessment frameworks for salmon conservation (Kareiva et al. 

2000, NMFS-NWFSC 2001, ISAB/RP 2005-5). 

The latter risk frameworks are efforts to integrate the 4-Hs (Hydro, Hatcheries, Habitat, and 

Harvest) in the Columbia River Basin. The ISAB emphasizes that this integration is crucial to 

effective harvest management of Columbia River Basin salmon. The most recent and related 

model reviewed by the ISAB and ISRP was the “All-H Analyzer” that the Northwest Power and 

Conservation Council staff proposed to use to establish numerical objectives for anadromous 

fishes, including natural returns, hatchery escapement, and harvest at the subbasin, province, and 

basin levels. While the review was critical of the current version of AHA, the review noted: 

“...the ISRP&AB emphasize that there is a clear need for quantitative analysis, 

including disciplined use of analytical and exploratory modeling, to improve fish and 

wildlife management in the Columbia River Basin, particularly the integration of 

natural and hatchery production with habitat actions at the subbasin level. We strongly 

agree with the Council staff’s observation that a major problem within the Columbia 

Basin is the lack of clearly articulated objectives integrated across the four Hs at the 

subbasin, province, and basin levels. Without these objectives, it is difficult to prioritize 

project implementation and monitoring activities. A key to developing these objectives 

is a comprehensive, integrated analysis of habitat, hatchery, hydrosystem and harvest 

actions.” (ISAB/RP 2005-5, Feb. 2005)

The ISAB notes that many of the elements of a sound scientific foundation are being 

progressively developed. Realistically, though, the complex interaction of human activities 

with Pacific salmonids in the Columbia River Basin and the changing environmental 

conditions (e.g., see Background Section 7.d, Climate Change) suggest that the foundation 

will continue to develop for years to come. For example, the recent initiative to mass-mark all 

Chinook, coho, and steelhead produced in federally supported hatcheries has been promoted 

as a means to support recovery of naturally produced salmon while providing for the selective 

retention of marked salmon to support fisheries (mass-marked selective fisheries). If, 

however, a limiting factor to recovery of natural salmonids is competition with the massive 

numbers of hatchery fish produced in the Columbia River Basin, then this initiative may 

actually prove to be detrimental to recovery (for example, see Sweeting et al. 2003, Levin and 

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ISAB 2005-4 Harvest Report 

Williams 2002, Levin et al. 2001; also see Background Section 7.c, The Hatchery Paradigm

and Ocean Carrying Capacity). Furthermore, the current implementation plans for mass 

marking and selective fisheries will severely compromise some important aspects of data 

collection that bear on the estimation of harvest mortality rates. The issue of mass-marking 

and selective fisheries is addressed further in Question 3 below. Without research programs

directed to evaluate this issue, however, the value of mark-selective fisheries will remain 

uncertain, particularly as the mortality of released fish (i.e., incidental or non-reported 

mortality) becomes a significant component of the total mortality attributed to harvest.

The biological basis for assessments and estimation of spawning escapement goals or 

recovery goals ultimately provides advice for the development of the fishery management 

plans. Currently, the development of harvest regulations requires advice on limitations 

imposed by the constraint to protect listed ESUs (Evolutionary Significant Units, or 

component populations) that must be considered during the development of fishing plans to 

access other harvestable production. For Columbia River Basin listed ESUs, this becomes a 

challenging task involving multiple listings and numerous fisheries both in the ocean and 

within the river. 

For each listed species in the Columbia Basin, the Pacific Fishery Management Council 

Salmon Pre-Season III Report’s Appendix A (www.pcouncil.org/salmon) lists the ESU, 

populations representing the ESU in the Salmon Fishery Management Plan (FMP), ESA 

Consultation Standards (guidance provided annually by NOAA Fisheries), and the fishery 

management measures intend to comply with the Standards. Text in the PFMC Salmon PreSeason III Report’s Appendix A provides a succinct statement of how listed species are 

treated under the salmon fishery management plans (table numbers refer to tables in the PreSeason III report). 

“Since 1989, NMFS has listed 16 Evolutionarily Significant Units (ESUs) of salmon under 

the ESA (Table A-1). As the listings have occurred, NMFS has initiated formal section 7 

consultations and issued biological opinions (Table A-2) that consider the impacts 

resulting from implementation of the Salmon FMP, or from annual management measures, 

to listed salmonid species. NMFS has also reinitiated consultation on certain ESUs when 

new information has become available on the status of the stocks or on the impacts of the 

Salmon FMP on the stocks. Some opinions have concluded that implementation of the 

Salmon FMP is not likely to jeopardize the continued existence of certain listed ESUs. 

Other opinions have found the Salmon FMP is likely to jeopardize certain listed ESUs and 

have identified reasonable and prudent alternatives that would avoid the likelihood of 

jeopardizing the continued existence of the ESU under consideration. The consultation 

standards referred to in this document include (1) reasonable and prudent alternatives, (2)

conservation objectives for which NMFS conducted section 7 consultations and arrived at 

a no-jeopardy conclusion, and (3) NMFS requirements under section 4(d) determinations. 

Amendment 12 to the Salmon FMP added to the list of stocks in the salmon management 

unit the generic category “species listed under the ESA” and the respective escapement 

goal to “manage consistent with NMFS consultation standards or recovery plans to meet 

immediate conservation needs and long-term recovery of the species.” Amendment 14 to 

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ISAB 2005-4 Harvest Report 

the Salmon FMP specified those listed ESUs and clarified which stocks in the Salmon 

FMP management unit were representative of the ESUs. 

NMFS, in a March 4, 2005 letter to the Council, provided guidance on protective measures 

for listed species for the 2005 fishing season. The letter summarized the requirements of 

NMFS’ biological opinions and 4(d) rules which are to be applied to the 2005 

management season. The ESA consultation standards and the exploitation rates (or other 

criteria) projected for the 2005 management measures are presented in Table A-3. Some 

listed stocks are either rarely caught in Council-area fisheries (e.g., spring chinook from 

the upper Columbia and Willamette rivers) or already receive sufficient protection from 

Salmon FMP and ESA consultation standards for other listed ESUs (e.g., Central Valley 

spring chinook). NMFS has determined that management actions designed to limit catch 

from these ESUs, beyond what will be provided by harvest constraints for other stocks, are 

not necessary.” (Salmon Pre-Season III Report for 2005, Appendix A)

In reviewing the scientific basis for management objectives the ISAB encountered two 

notable issues: 

1. identifying the production units used in management planning to represent listed ESUs 

(i.e., the correspondence between production units and ESUs), and 

2. understanding the technical and analytical basis of the biological opinions. 

Although Table A-3 of the Pre-Season III report relates “stocks” represented in the salmon 

FMP, it does not identify the populations used in the assessment of these stocks such that an 

assessment’s technical basis is reviewable. To address this, the ISAB collated a large table of

ESUs, component populations identified by the NOAA technical review teams, indicator 

stocks and assessment methods, and the harvest management units for ocean and in-river 

management (Appendix B). While this table was informative in organizing our understanding, 

it also clearly demonstrates the paucity of quantitative assessments that form the basis of 

harvest management for both listed and other production units within the Columbia River 

basin. 

The technical bases for some biological opinions were not apparent and their adequacy for 

achieving recovery was uncertain. To permit an action that results in "take" (including 

harvest) from a listed population, the ESA requires a determination that the take is incidental 

to the proposed action (and not the primary purpose of the action) and that the anticipated 

level of take will not "jeopardize the continued existence" of the population. Regulations 

interpret "jeopardize the continued existence" to mean "appreciably reduce the species

likelihood of surviving and recovering in the wild." 

Because fishing is not completely selective, individuals from listed populations may be caught 

during the course of harvests intended to target other populations. Because the harvest in the first 

place is deliberate, and the take of the listed population is owing to failure of selectivity, the 

degree to which this is "incidental" is a matter of interpretation. 

The level of harvest mortality that results for the listed population can be quite high -- rates in the 

20% to 50% range can be encountered. A healthy, productive salmon population can sustain such 

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ISAB 2005-4 Harvest Report 

harvest mortality, so managing the fishery on the aggregate with a view simply to maintaining 

the gross level of production of the more productive components will lead to these sorts of 

harvest mortalities on weak (less productive) or listed stocks. Endangered populations often are 

not as productive as their healthy counterparts, so the level of harvest based on the aggregate of 

populations may be excessive and not sustainable by the weaker component populations. 

Similarly, because hatchery production may give rise to productivity levels considerably higher 

than the natural production of the same species, a fishery managed to access the hatchery 

component of the population may not be sustainable by the natural component. 

Another common characteristic of salmon population dynamics that is relevant to biological 

opinions, even for normal healthy populations, is a high degree of temporal volatility. Between 

good years and bad years, the productivity can vary through a ten-fold range, or more. As a 

result, the assessment of sustainability of a proposed harvest level is inevitably subject to a large 

degree of temporal uncertainty. The uncertainty owing to real process variation will be

compounded by uncertainty owing to measurement error in the estimation of the productivity, 

implementation error owing to imperfect control of the fishing activities themselves, and 

uncertainties having to do with effects of other factors, such as attempts to mitigate for other 

components of mortality or productivity. 

The regulatory determination through a biological opinion, therefore, of whether or not a 

proposed harvest level is compatible with survival or recovery of a listed population, will be illdefined unless it is guided by hard quantitative standards for what constitutes an appreciable 

reduction in the probability of survival and recovery, as well as how the determination should 

factor in the various pertinent uncertainties. At present such quantitative standards have not been 

stated for the regulatory determinations. Biological opinions have been generated for permitting 

incidental harvest of various listed salmon ESUs using a variety of kinds of data, of varying 

degrees of completeness and reliability, and analyzed by a variety of statistical and modeling 

methods. To date, these determinations related to harvest have been conducted in a relatively 

collegial atmosphere with the regulated community, and the decisions have not been contested at 

a disruptively vigorous level (in contrast to those related to operation of the federal hydro 

system). Whether or not this kind of acceptance of a loosely defined process will continue in the 

future is an open question. It would be prudent for NOAA Fisheries and the Fish and Wildlife 

Service to develop more explicit, quantitative, standardized methodology, if only as a defensive 

precaution. Certainly, many other aspects of regulation of listed salmon have come under very 

intense and rather costly debate. 

NOAA Fisheries and the Fish and Wildlife Service have been aware for some time of the 

ambiguities in the existing legislation and harvest regulation, and joint efforts have been 

underway to attempt to develop more complete and standardized guidance. It would be good to 

ensure communication between the salmon decision-making apparatus and these guidance efforts 

to capitalize to the extent possible on current thinking. For example, clear statements of critical 

population sizes for populations or ESUs (based effective population sizes, Waples 2002 a,b) and 

threshold exploitation rates necessary to limit harvest mortalities to achieve these critical 

spawning numbers (these rates will vary with productivity, poor salmon survival will require 

reduced exploitation rates). If critical population sizes are not achieved within a generation, then 

immediate responses could be built into a harvest management planning in order to maintain 

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ISAB 2005-4 Harvest Report 

spawning population sizes and the potential for recovery within an agreed time frame. 

Documentation of the technical bases for decisions should be peer reviewed, understandable, 

available to the public, and include adaptive response mechanisms if recovery does not proceed 

along an expected recovery trajectory. While the ISAB recognizes that elements of these points 

are contained in some biological opinions, the technical assessments and recovery targets are not 

readily apparent. 

In May 2005, the National Marine Fisheries Service (NMFS) released the “Biological Opinion 

on Impacts of Treaty Indian and Non-Indian Fisheries in the Columbia River Basin in Years 

2005-2007 “(F/NWR/2005/00388). This opinion complements assessments for ocean fisheries 

and addresses the proposed fisheries to be conducted pursuant to the 2005-2007 Interim 

Management Agreement for Upper Columbia River Chinook, Sockeye, Steelhead, Coho and 

White Sturgeon (U.S. v. Oregon Parties 2005). The parties to the 2005-2007 Interim

Management Agreement are: the States of Oregon, Washington and Idaho, the Nez Perce Tribe, 

the Confederated Tribes of the Umatilla Indian Reservation, the Confederated Tribes of the 

Warm Springs Reservation of Oregon, the Yakama Indian Nation, the Shoshone-Bannock 

Tribes, the Bureau of Indian Affairs, the U.S. Fish and Wildlife Service and NMFS. In reviewing 

the biological status of these resources NMFS concluded that: 

“ ... given all the factors for decline—even taking into account the corrective measures 

being implemented—it is still clear that the affected ESU’s biological requirements are 

currently not being met under the environmental baseline. Some of the ESUs are 

responding favorably to improved natural conditions and actions taken to reduce humaninduced mortality. However, the survival and recovery of the species depends on their 

ability to also persist through periods of low ocean survival. Thus circumstances are such 

that there must be a continued improvement in the environmental conditions (over those 

currently available under the environmental baseline). Any further degradation of the 

environmental conditions could have a large impact because these ESUs are already at 

risk. In addition, efforts to minimize impacts caused by dams, harvest, hatchery operations, 

and habitat degradation must continue.” (p. 85, Section 2.2.7 Summary)

Table 29 of this biological opinion specifies incidental take limits and expected incidental take 

(as proportion of total run size) of listed salmonids for non-Indian and treaty Indian fisheries 

under the 2005-2007 Interim Management Agreement. Table 30 presents a schedule of harvest 

rates that vary with abundance of certain upriver stocks. Fisheries will be limited by the 

incidental takes specified for an abundance level in order to achieve critical spawning abundance 

levels and maintain progress towards recovery targets. The Interim Management Agreement for 

2005-2007 continues to rely on a management framework very similar to that proposed in the 

2001 Agreement. Apart from the modification designed to accommodate a change in 

management period (for summer Chinook), the 2005-2007 Agreement proposes to extend the 

harvest rate schedule considered in 2001-2005 Interim Agreement. Based on these 

considerations, NMFS concluded that continued reliance on the harvest rate schedule in the 

2001-2005 Interim Agreement and the impacts associated with the proposed 2005-2007 fisheries 

are not likely to appreciably reduce the likelihood of survival and recovery of Snake River fall 

Chinook. This assessment appears to continue the ISAB’s concern commented on above and 

does not appear to be well supported by the analysis provided. 

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ISAB 2005-4 Harvest Report 

Performance Indicator 2: Are there clearly defined management objectives? 

While the process components of Indicator 2 appear adequate and functional, the biological 

components for some production units do not, and need to be more explicitly stated to guide 

management. Inadequacy of the biological component may again reflect limitations to the 

historical data combined with the extent of depression in abundance for some production units. 

For example, significant progress has been made in identifying the independent production units, 

but conservation and recovery goals for them remain undefined. Further, criteria for defining a 

viable ESU are still under development (see ISAB 2005-3), and whether such recovery goals 

provide adequate production to meet socio-economic aspirations for harvest, and how quickly 

these goals can be met is unknown. The ISAB also notes that the functioning of the complex 

management process seems largely dependent on the cooperation of dedicated individuals rather 

than a formal structured and integrated management process. 

As noted in Section 4a, the interpretation of clearly defined management objectives 

encompasses: definition of the production units13 to be managed; biological conservation targets 

for each production unit; and objectives and priorities for fisheries including socio-economic 

aspects, and clearly defined risk tolerances. Considerable effort goes into defining management 

objectives both at the long-term policy level and for annual harvest planning. 

Production units to be managed and their associated conservation targets are defined in fishery 

management plans of the PFMC and for the in-river management. 

The Pacific Coast Salmon Plan (FMP) provides the framework for marine harvest management 

by the Pacific Fishery Management Council. Chapter 3 of the FMP identifies salmon 

management units and conservation goals for “stocks” that are significantly affected by the 

PFMC’s actions, specifies criteria and procedures to prevent over-fishing, and contains 

additional information regarding stocks listed under the ESA and by-catch. Chapter 5 of the FMP 

specifies management objectives and considerations for fisheries, including allocation among 

commercial and recreational fishing sectors and across geographic areas. This section contains 

nine "overall" fishery management objectives that can be paraphrased as: 

1. set ocean exploitation rates consistent with ESA consultation or recovery standards, or 

rebuilding plans; 

2. fulfill Indian treaty obligations and other federally recognized fishing rights; 

3. maintain fishing seasons that support established commercial and recreational fisheries 

while meeting allocation objectives in a fair and equitable manner; 

4. minimize incidental catch mortality; 

5. manage for optimum yield that encompasses the quantity and value of food produced, 

recreational value, and the social and economic values; 

6. manage fishing effort fairly and evaluate alternative effort management systems; 

7. with effort management, support enhancement of salmon abundance to facilitate 

economically viable and socially acceptable seasons for all fisheries; 

 

13 Production unit in this discussion is a spatially defined group of salmon populations and hatcheries that are 

determined by the responsible agencies as a basis for conservation and management. 

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ISAB 2005-4 Harvest Report 

8. achieve long-term coordination with other salmon management entities and consistency 

with the Pacific Salmon Treaty; 

9. promote safety at sea in the recommendation of fishing seasons. 

Fishery management measures to constrain harvest within allowable limits are described in 

Chapter 6 of the FMP. The FMP does not explicitly state risk tolerances. Instead, the PFMC 

addresses uncertainty recognizing that the consideration of risk has many components, including 

risk to the salmon, risks to the commercial and recreational fishing sectors, risk to the capacity to 

meet legal obligations, and risk to safety of the fleet. These considerations are taken into account 

during the annual planning process that leads to the adoption of recommendations for fishing 

plans in light of the status of individual “stocks”, which was discussed in Section 3 of this report. 

For instance, uncertainty can be reflected in risk-averse assumptions used in the planning process 

(e.g., conservative projections of abundance, area closures to reduce contact rates on sub-legal 

sized fish or around river mouths, gear restrictions, incidental fishing mortality rates, buffers for 

effort response projections, timing of openings to reflect market demands or weather conditions). 

For listed ESUs, biological risk is considered by NOAA Fisheries when establishing jeopardy 

standards, providing annual guidance letters to the PFMC, and issuing Biological Opinions on 

recommendations for annual fishing plans. Ocean fisheries are monitored in-season and 

management actions are taken to ensure compliance with requirements set forth in regulations. 

Within the Columbia River, management plans are developed for the spring, summer, and fall 

seasons. These plans identify the salmon production units and their associated management 

objectives and constraints. Guidance is sometimes provided through multiple-year agreements 

between state, tribal, and federal co-managers, but plans are implemented annually to reflect 

expectations for terminal returns for specific populations. As with the FMP, risk tolerances are 

rarely specified in the Columbia River management plans. For listed ESUs and component 

populations, biological risk is considered explicitly in biological opinions. Uncertainty is taken 

into account in-season when regulations are established in response to data on production status 

and fisheries, so as to constrain fishery impacts within allowable levels. 

Socio-economic objectives for fisheries are usually not specified in the Columbia River 

management plans. Instead, the Columbia River Compact, like the PFMC, takes those 

considerations into account during the deliberative processes that establish in-season fishery 

regulations. The plans and in-season management actions are informed by legal requirements 

pertaining to the regulation of Treaty Indian fisheries through what are commonly known as the 

Conservation Necessity Principles,14 which limit the capacity to restrict the exercise of treaty 

fishing rights. These principles grew out of a process to redress a lengthy history of policies and 

regulations adopted by the States of Washington and Oregon, which had the effect of 

discriminating against treaty-protected fisheries. Under state regulation, non-Indian commercial 

and recreational fisheries had been allowed to take virtually all the harvestable fish, so the 

 

14 These principles have been embodied in a series of US Supreme Court cases dating back to the 1960's - they were

repeated in the US v Washington ruling and incorporated into Secretarial Order 3206 (American Indian Tribal 

Rights, Federal-Tribal Trust Responsibilities, and the Endangered Species Act) which was signed by the Secretaries 

of Commerce and Interior in June 1997. The Order sets forth policies and procedures to harmonize administrative 

responsibilities of NMFS and FWS under the ESA with tribal sovereignty and reserved rights. 

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ISAB 2005-4 Harvest Report 

remaining fish were needed to protect spawning escapements. Because Indian fisheries were the 

last in line, they were called upon to bear the brunt of the burden for perpetuating the resource. 

To protect the rights that tribes reserved in their treaties, the United States filed suit against the 

State of Oregon (U.S. v. Oregon) and Washington (U.S. v. Washington). The states' arguments 

that Indian fishing had to be closed for conservation did not prevail. The courts understood that a 

dead fish is a dead fish regardless of who catches it and recognized that the states' regulatory 

practices had been based on non-Indian societal values and wise-use notions of conservation. 

The courts determined that only fish in excess of the spawning escapement needs for future 

propagation could be taken and required the states to regulate fisheries so as to ensure that tribes 

would have the opportunity to take a specified share of the resource at their usual and 

accustomed fishing grounds and stations (in their treaties with the United States, the Columbia 

River tribes reserved the right to take fish at their usual and accustomed grounds and stations). 

The courts also acknowledged that only the tribes had the right to determine the best and wisest 

use of their share. To protect against future discrimination against treaty Indian fisheries, the 

courts established a strict definition for the term conservation. That definition led to the 

Conservation Necessity Principles as a concise statement of legal standards to be satisfied before 

treaty-protected Indian fisheries can be restricted for conservation purposes, the restrictions: 

• are reasonable and necessary for the conservation of the species at issue; 

• are necessary because the conservation purpose cannot be achieved through reasonable 

regulation of non-treaty activities; 

• are the least restrictive measures available to achieve the conservation purpose; 

• as stated or as applied, do not discriminate against treaty activities; and 

• are necessary because voluntary tribal conservation measures are not adequate to achieve 

the conservation purpose. 

Policy commitments such as these provide guidance for ESA consultations on fisheries, 

particularly when the government seeks an appropriate balance between trust obligations and the 

imperative of meeting the conservation needs of the listed species. This policy commitment and 

guidance related to treaty rights was reiterated in other documents and correspondence, including 

the All-H paper (Federal Caucus 2000) and subsequent consultations on harvest (page 103, 

Biological Opinion on Impacts of Treaty Indian and Non-Indian Fisheries in the Columbia River 

Basin in Years 2005-2007, F/NWR/2005/00388, May 2005). 

Performance Indicator 3: Is there adequate institutional capacity to constrain total 

fishing mortality? 

Since a multitude of institutions have regulatory authority over Columbia River basin fish, there 

would seem to be ample opportunity to constrain total fishing mortality through both regulations 

and enforcement. This multitude, though, presents difficult challenges for coordination and the 

aggregate result has often been less satisfactory than needed. A portion of the limitation to 

constraining total fishing mortality is due to the inability to scientifically sort out population 

dynamics and total mortality for individual populations involved in multiple, mixed-stock 

35 
ISAB 2005-4 Harvest Report 

fisheries. Therefore, while there is apparently adequate institutional processes developed, the 

ability to constrain total mortality on specific production units remains less than necessary, 

unless very broad-based harvest reductions are implemented in times and areas where the stock 

is expected to be present. 

Cooperation and coordination across management jurisdictions to attempt to achieve 

management objectives for individual production units has developed because no single entity 

has the authority and responsibility for ensuring that management objectives are met for a given 

population. The need to coordinate harvest impacts on a given production unit involves many 

separate management jurisdictions and is accomplished through the joint efforts of scientists 

responsible for providing scientific advice to decision makers and through formal agreements 

among managers. Attainment of management objectives (spawner escapements or target 

exploitation rates) for individual production units, however, is problematic. 

For an escapement objective for each salmon population to be achieved, not only must 

management define the desired number of spawners for each population, it must also regulate 

multiple fisheries to achieve them. This level of harvest management control in salmon fisheries 

is unrealistic because most fisheries simultaneously exploit a mixture of salmon populations, and 

the actual catch from each is usually unknown. Additionally, errors in pre-season forecasts, 

changes in return timing, variation in the response of fishermen to opportunities and weather all 

confound our ability to accomplish management objectives for individual production units. 

Further, in the context of managing fisheries, it is important to differentiate what is known about 

salmon and our capability to control harvest impacts on specific populations. The latter is 

referred to as management control error and is frequently not fully accounted for in planning. 

The capacity to constrain harvest of Columbia River salmon is determined by the institutions 

involved in regulating fisheries throughout the migratory ranges of individual production units. 

The institutions involved with salmon include many private, local, regional, state, tribal, federal, 

foreign, and international entities. These entities operate within their own jurisdictions, but often 

have overlapping authorities and responsibilities for a range of functions, including harvest 

management, regulation, habitat protection, flow control, permitting, enforcement, and research. 

Institutions for harvest management exist to execute a suite of legal mandates and constraints 

that apply to directed harvest, by-catch, protection, and recovery. Meeting these objectives 

entails the performance of several different management tasks: the implementation of 

management plans that contain multiple objectives for salmon conservation and fishery 

participation (as listed above under Performance Indicator 2); the assessment of population status 

to provide the basis for annual decision making; the design of regulations to control and 

distribute fishing mortality; the coordination of decisions under state, state-tribal, federal, and 

international authorities; the implementation and enforcement of regulations; the monitoring and 

evaluation of regulatory performance. 

Ultimately, the effectiveness of harvest management institutions in constraining harvest depends 

on whether the jurisdictions affecting the harvest of Columbia River salmon have decision 

processes that are sufficiently coordinated to: 

• collect consistent biological data; 

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ISAB 2005-4 Harvest Report 

• accomplish management objectives for individual production units; 

• accept common management objectives and responsibilities; 

• adequately account for uncertainty in information and management control; 

• be transparent and accountable, including sound scientific information, stakeholder 

participation, and enforcement. 

As described above, the biological data needed to provide a sound scientific foundation for 

harvest management include data on the fishery and escapement, estimation of exploitation rates 

on populations, and status relative to their production capacities. These data should allow 

identification and quantification of all sources of mortality affecting a given population through 

out its life cycle, provide biological goals for management, and provide clear signals of nonsustainability. Problems related to continuing uncertainties about population dynamics and to the 

limitations of fishery and biological data were discussed in this section above. The data question 

pertaining to the effectiveness of salmon harvest management institutions is whether the data 

collection processes of various jurisdictions are sufficiently coordinated to ensure that data are 

consistent and complete across jurisdictions and time. Data consistency is in fact a problem over 

multiple jurisdictions as well as over time, creating a need to develop standards and protocols for 

data collection. These are being developed and should gradually improve regional evaluations. 

The US Chinook Technical Committee of the PSC developed draft data collection standards 

several years ago, and the Coho Technical Committee has recently begun a similar initiative. 

The management objectives and responsibilities of the many jurisdictions involved in Pacific 

salmon harvest management are defined by applicable law, including Indian treaties, 

international agreements, and federal and state laws, and interstate compact. Various fora exist 

(flow chart, Figure 6) to address the translation and coordination of legal guidance into common 

understandings of objectives and responsibilities for harvest management. The interaction of 

harvest management with recovery of listed salmon populations, however, introduces additional 

ambiguity about management objectives for lack of accepted and well defined quantitative 

jeopardy standards for survival and recovery. The institutional landscape of harvest management 

and recovery actions is sufficiently connected through the ESA consultation process, though, to 

implement survival and recovery objectives once defined. Ocean fishery harvest management is 

already connected to jeopardy standards through guidance letters from the Secretary of 

Commerce and records of harvest management decisions submitted to the Secretary of

Commerce. 

The harvest management decision process, as illustrated in the timeline for harvest management 

decisions for Columbia River salmon (Table 1), is transparent to the extent that it is a public 

process, subject to notice and comment, and open to public observation and participation. The 

process involves scientists in data collection, analysis, recommendation and evaluation to an 

extent unmatched in other marine fisheries. Stakeholders are formally involved as advisors. 

Scientific information forms the basis of both advice and decision-making. Limits on 

transparency are caused by the complexity of the analyses and decision process, the multiple 

stages of data analysis and interpretation, and number of groups involved, overwhelming reliance 

on “gray literature,” unclear processes for documenting and justifying critical assumptions, and 

unclear processes for archiving and providing access to fundamental original data, and 

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ISAB 2005-4 Harvest Report 

intermediate steps in complex analyses. This reflects the complexity of the legal, cultural, 

economic and biological context of the fisheries. 

An important component of accountability is enforcement. The effectiveness of harvest 

management implementation depends in large part on the extent to which harvest regulations can 

be enforced. This makes enforceability of regulations an important consideration to their design, 

requiring that they be clear and unambiguous. Marine harvest management conducted under the 

auspices of the Pacific Fishery Management Council is advised on matters of enforcement by its 

Enforcement Consultants committee, comprising representatives of state and federal fishery 

enforcement authorities. Enforcement of in-river harvest regulations is overseen by tribal and 

state conservation enforcement authorities. 

5. ISAB Recommendations 

Although harvest management and salmon recovery can be assisted by the use of best available 

science, science alone is not likely sufficient. Freshwater habitats and salmon runs have been so 

altered in the Columbia River Basin that conservation and restoration of naturally produced 

Pacific salmonids will require strong social commitment, cooperation between agencies, and 

extensive and continuing financial investments. The ISAB is impressed with the management 

processes that have been developed and the continued efforts to expand the scientific bases for 

recovery. Ironically, the elements of science, commitment, cooperation, and investment are all 

evident and progressing in the Columbia River Basin. There remains, however, extensive 

concern for conservation of naturally produced salmonids and the effect of harvest on their 

conservation. Harvest is only one part of this complicated picture, but fishing is frequently 

targeted as a first management action because it removes mature salmon that could otherwise 

return to reproduce. 

Among the many resource use conflicts within the Columbia River, salmon harvest is often 

thought by non-experts to be the predominant human impact on salmon. As a result, while there 

will be varying public support for allowing fisheries on listed ESUs and component populations, 

there will be less understanding about the impact of the hydro-system, habitat loss, and 

hatcheries on these same fish. The issues involved with harvest management are complicated, 

with many agencies and populations involved and numerous historical complications (past 

impacts of development, mitigation and legal background including the massive hatchery 

production, conflicting objectives and limited historical data, etc.). Significant progress, 

however, is being made in several areas important to harvest management (as noted earlier in 

section 4b) such as the definition of independent population units (NOAA TRT’s and State 

agencies), definition of population and ESU viability, establishment of the Pacific Salmon Treaty 

and role of the PMFC in limiting ocean fishing impacts, and the renewed in-river fishing 

agreements. In spite of these actions, harvest is likely to remain a concern because: 

• there has been limited evidence of progress toward recovery (until very recently); 

• the basis for annual variability in salmon returns is not well understood or explained to the 

public; 

• hydro and habitat issues are seen as very long term issues and not easily managed; 

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ISAB 2005-4 Harvest Report 

• hatcheries are commonly used and understood to support harvest, particularly with the 

recent development of mass marking and selective fisheries; 

• ocean mixed-stock fisheries in Canada and the United States continue; and 

• harvest management systems are poorly understood. 

Many of these sources of concern could be addressed through an effective communication plan 

to improve public understanding of how allowable harvest levels are established and how 

effective modern management processes can be in achieving their management goals. In this 

understanding, it would also be important to identify the inter-connections of the 4-H’s and how 

lack of attention to any one “H” limits progress in the others. An excellent current example is the 

development of mass-marking of hatchery fish and mark-selective fishing to increase the 

harvests of hatchery fish while maintaining fishery impacts on unmarked fish (usually naturally 

produced salmonids) within allowable rates. One goal of this plan is to assist recovery of listed 

species; but if habitat is not restored, then there may not be the productive capacity to sustain the 

natural returns. In addition, if juvenile hatchery fish compete with natural fish, adult recovery 

may not result due to continued limitations during juvenile rearing. 

While the ISAB has been favorably impressed with the development of biological science and 

management processes, we note significant concern for three fundamental components of harvest 

management. These include: 

1. a paucity of quantitative data for analyses by population units (core data); 

2. very limited evidence of assessment analyses by production units to provide a biological 

basis for production goals and trends in status; and 

3. limited evidence of accounting for uncertainty in management plans with the exception of 

reference to precaution in the National Standard Guidelines. 

(While precaution is not explicitly referenced in the MSFCMA, it is implied through 

overfishing prohibitions in National Standard 1 (OY). Precaution is referenced, however, in 

the National Standard Guidelines issued by NMFS, in which it states that specification of OY 

should be done using a precautionary approach. That statement is the motivation for the 

technical guidance provided in Restrepo et al. (1998) and the more recent Report of the 

NMFS National Standard 1 Guidelines Working Group (2003).15) 

Recommendation 1. Core Monitoring Data: The ISAB has commented previously (ISAB 2003-

3) on the essential need for a set of core quantitative data to be monitored annually in all 

production units or, at least, in representative units that may be used as “indicators” of 

productivity and trends in abundance over time. Given efforts to restore habitat productivity and 

annual variation in flow, variability in ocean productivity, inter-annual climate variation, and 

varying levels of exploitation over time ... how would an agency account for a declining trend in 

spawning numbers without credible data sets that provide for analysis? Is a declining trend due 

to the environment or exploitation rates? Data sets for many production units in the Columbia 

River proved to be very difficult to locate and frequently involved major assumptions, such as 

fixed age-at-return or use of constants in the estimation of spawning numbers. With the obvious 

importance of defining recovery goals and then monitoring progress to recovery, establishing 

 

15 Report of the NMFS National Standard 1 Guidelines Working Group, Nov. 2003; available at: 

www.nmfs.noaa.gov/directives/

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ISAB 2005-4 Harvest Report 

quantitative indicator systems within ESUs is essential for a credible harvest management 

system. A monitoring framework with sampling designs should be required for each ESU and 

production unit defined by the TRTs and by agencies managing stocks that are not listed. 

Programs to monitor specific populations have typically used coded-wire tags to identify 

exploitation patterns, and to estimate exploitation rates and survival after release. Tagging could, 

however, also involve PIT tags or active acoustic tags to allow fuller life-cycle monitoring. 

Recommendation 2. Documented Assessments: While the ISAB reviewed many TRT reports, 

biological opinions, scientific papers, and management plans, there were very few quantitative 

and documented assessments of individual production units or ESUs, including both natural and 

hatchery production. Such assessment reports would typically identify the methodology, 

delineate the spatial limits of the production unit, provide the historical data used in the analyses, 

conduct quantitative analyses to estimate biological management targets (target number of 

spawner, sustainable exploitation rate, etc.), identify limitations to the data and analyses, and 

identify advice for management (e.g., current status or trend in abundance, forecast of expected 

returns, and recommend management actions). In both the recent reviews of subbasin plans and 

during this review, very few examples of thoughtful population assessments were evident. 

Consequently, the ISAB has to question the basis of biological advice on Pacific salmon that 

subsequently becomes the basis for harvest management planning. Furthermore, the ISAB 

strongly cautions against the collection of data without parallel careful design, use, and 

evaluation. Collection of the data is, of course, the first priority, but only by using data and 

assessing the dynamics of a production unit can errors be detected and corrections made. 

Detailed assessments must be documented and peer reviewed to provide quality control to the 

scientific basis of management planning. 

Recommendation 3. Accounting for Uncertainty: While many documents refer to uncertainty, 

there were very few examples of actually estimating uncertainty or accounting for it in a 

management plan. With limited historical data and changing habitats through time, analysts 

likely know much less about the production dynamics of Pacific salmonids than is assumed. The 

effect of environmental variability between years is inherently large, environmental conditions 

are not stable over time, biological communities and ecosystems are complex, and the 

parameters estimated from spawner/recruitment analyses should be expected to apply at best as a 

long run average, and at worst to be significantly biased because they represent a sample 

representing too small a time period from a process with long-term variation. None of the data 

collected in the natural environment is collected without error, and errors in achieving an inseason management target are seldom accounted for. Overall, uncertainty is very likely to be 

much greater than appreciated or accounted for, and predictability less. 

It should be understood that there is a relationship between data quality, uncertainty, and 

managing to a target value. To apply uncertainty in a harvest management context, the analyst 

needs an estimate of the uncertainty, a management target value, and a specified level of risk 

tolerance. If data quality is poor, uncertainty is expected to be large, and the management 

adjustment to ensure a high probability of achieving the target would also be large (i.e., the

impact of poor data would be borne via reduced fishing opportunity). With poor data quality and 

no management adjustment, the salmon stock would be at increased risk due to the uncertainty of

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ISAB 2005-4 Harvest Report 

staying within the management target. Historically, this latter scenario likely accounted for 

frequent over-fishing of the salmon resources. 

The ISAB recommends that guidelines for the estimation and accounting of uncertainty in 

management targets and in-season management control be developed and applied in the 

management of listed ESUs. All sources of fishing mortality must be accounted for and a level of 

risk tolerance established through public consultation. While the ISAB was impressed with the 

intensive process used for salmon management, we also recommend analysts review whether 

current levels of harvest impact are consistent with the quality of data and level of uncertainty in 

processes, and provide the expected likelihood of recovery for these listed species. 

Recommendation 4. Adaptive Management in Salmon Recovery: Given the limitations in 

historical data, the inherently large uncertainty in salmonid ecosystems, and the complexity of 

management processes involved in harvest management of Columbia River salmonids, the ISAB 

recommends application of adaptive management principles in salmon recovery. Adaptive 

management is a systematic process for continually improving management policies and 

practices by learning from the outcomes of operational programs. It is most effective if active 

management is employed. Programs are designed to experimentally compare selected policies or 

practices by evaluating alternative hypotheses about the system being managed, and monitoring 

systems are established to continually assess these alternatives (see Walters 1986, Lee 1999). 

Adaptive management is not just adjusting to the outcomes of trial and error (see Lee 1999) but 

involves a more rigorous set of strategies and a comprehensive planned set of adjustments 

conditional on various outcomes. In complex biological and social systems such as the Columbia 

Basin, the challenge is frequently one of maintaining the agreed design (i.e., a response) when 

impacts on the social and cultural systems increase. Given the limited progress in developing 

agreed recovery plans, the ISAB believes that a systematic approach to testing alternative actions 

with an emphasis on achieving secure spawning escapement levels should again be seriously 

considered. 

A similar approach has previously been envisioned, but not implemented, with the development 

of the PATH process in the mid-1990s, but little application resulted from that effort (see 

Marmorek and Peters, 2001; and papers in the Canadian Journal of Fisheries and Aquatic 

Sciences Vol. 58, issue 12). There are, however, potential problems with implementing an 

adaptive management program in a complex ecological and cultural system such as the 

Columbia Basin that may explain this inaction. Examples of potential problems include: 

1. the inherent variability in natural ecosystems and the difficulty of planned manipulation 

of large systems; 

2. this variability also results in “noisy” character of data collected and leads to the need 

for large perturbations to detect response and isolate causal factors - social values and 

perceptions of risk may work against the ability to generate strong signals 

through adaptive management actions; and 

3. costs of monitoring and evaluation are often difficult to support over the longer term. 

Despite these potential problems, given the extensive financial investments in the basin already 

and the potential future costs of not achieving recovery, adaptive management should be reconsidered. The basic process to implement an adaptive management approach would be to 

41 
ISAB 2005-4 Harvest Report 

establish initial recovery targets through a set of agreed management actions, with a specified 

risk tolerance, and for a specified number of years. If progress to that goal is not achieved in a 

limited number of years, then an alternative set of actions, identified in advance, would be 

implemented with a more stringent requirement to achieve recovery and lower level of risk. As 

the system responds to actions taken, insight is gained which can be used to reduce uncertainty 

between alternative future actions and to direct monitoring programs to priority information 

needs. An important but indirect value in this process is a positive feedback for maintaining a 

strong monitoring and assessment program. Furthermore, the management actions should be 

sensitive to variation in marine productivity. Spawning abundances should be protected so that 

there remains a high likelihood of not “going backwards” on recovery except when rare 

configurations of marine conditions overwhelm the biological response. 

Recommendation 4 may also be an appropriate action for addressing how the Columbia River 

Basin should assess and adapt to the risks of climate change on Columbia River salmonids. The 

ISAB considered a recommendation concerning preparation for climate change but decided that 

such considerations would require more time and were likely beyond the current task of 

reviewing harvest management. At this juncture, it seems sufficient to note evidence that oceanic 

cycles affect salmonid productivity and harvest opportunity at yearly and decadal scales, and that 

global climate appears to be on a warming trend that may affect long-term sustainability of both 

production and harvest. The ISAB sponsors may wish to consider a broader assignment 

concerning climate change impacts and longer-term forecasts of its impacts. 

As will be discussed in Section 7d of this report, the ISAB anticipates major increases in 

understanding of climate change and climate cycles in relation to salmon and other natural 

resources in the next few years, as well as significant increases in the uncertainty of production 

forecasts in the short to medium term. Harvest managers and the harvest industry need to be 

informed of this increased understanding and to be prepared to change their procedures 

accordingly for conducting near-term and long-term assessments, setting annual quotas, and 

harvesting fish. 

6. Questions Posed to the ISAB 

The following four questions were developed by the ISAB from the many questions posed to it 

by NOAA, NWPCC, and CRITFC. The sources of original questions contained in each of these 

four are noted in parentheses. 

1. Contrast current and past harvest practices (NOAA Fisheries question), addressing 

whether harvest rates and total fishing mortality on Columbia River stocks have 

increased, decreased, or remained constant (CRITFC question)? 

Fishery impacts on Columbia River salmon have been reduced since the mid-1980s due to 

harvest management measures taken to respond to a variety of factors. Three examples are 

presented in Appendix C to illustrate reductions in fishery impacts on Columbia River salmon 

and discuss underlying reasons: (1) Up-River Bright fall Chinook (URB); (2) coho; and (3) Brun steelhead. 

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ISAB 2005-4 Harvest Report 

• The URB example discusses the need for coordinated, collaborative management to meet 

stock-specific management objectives, provides information on how harvest management 

strategies affect fishery impact rates, and illustrates the importance of having information on 

productivities and differences in exploitation patterns of component populations. Based on 

analysis of coded wire tag (CWT) data by the Pacific Salmon Commission’s (PSC) Chinook 

Technical Committee, adult equivalent brood year exploitation rates on URBs have 

decreased from about 80% in the mid 1980s to 45%. Less data is available to evaluate 

changes in fishery impacts on the Snake River fall component of URBs, but indicate that 

adult equivalent brood year exploitation rates have fallen from around 70% to 20%. In-river, 

harvest rates of URBs and Snake River fall Chinook exhibit different patterns. The URB 

harvest rate has declined from approximately 60% in the mid 1980s to less than 30%; 

spawning escapement goals have consistently been achieved and have been substantially 

exceeded in recent years. In comparison in-river harvest rates on Snake River fall Chinook 

have decreased from about 60% in the mid-1980s to about 20%. Dam passage mortalities of 

URBs and Snake River fall Chinook are significant (e.g., accounting for a mortality rate 

occasionally exceeding 30% on URBs since 1986). 

• The coho example discusses the importance of interpreting changes in fishery impact rates 

within the context of fishing patterns and management responses to adjust to changes in legal 

requirements. Columbia River coho are predominantly produced by hatcheries constructed to 

mitigate for damage associated with dam construction. Exploitation rates on Columbia River 

coho are not based on analysis of CWT data, but rather on an index derived from catches and 

escapements. This index indicates that total exploitation rates have fallen from over 80% in 

the mid-1980s to about 50%. The decrease in exploitation rates is even more dramatic for 

ocean fisheries, which have declined from about 80% to less than 20%. These decreases have 

been triggered by conservation concerns for commingled naturally spawning stocks from the 

Oregon coast and remnant populations in the lower Columbia River. Because of markselective fisheries in recent years, reductions in exploitation rates on naturally spawning coho 

from the Columbia River are greater than indicated for hatchery fish. 

• The B-Run steelhead example provides a contrast to the URB and coho examples both in 

terms of fishing patterns and the quality of information available for harvest management. 

Separation of B-Run fish from commingled hatchery and wild fish is based on assumptions 

regarding the timing of passage at Bonneville Dam and fish size; this example illustrates 

some difficulties, ambiguities, and inconsistencies that can result from management by 

assumption. This stock is not significantly impacted by ocean fisheries. Available data 

indicate that in-river harvest rates have declined from over 30% in the mid 1980s to less than 

10% since the mid 1990s. 

2. Does current harvest management adequately manage and protect ESA listed naturally 

spawning populations (NWPCC question)? 

This question cannot be definitively answered until recovery objectives are established for ESAlisted populations and determinations are made as to what component populations within ESUs 

must be protected to maintain ESU viability, and quantitative risk tolerances are adopted. Until 

then, ambiguities will continue to surround interpretation of the phrases “adequately manage and 

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ISAB 2005-4 Harvest Report 

protect” and “ESA-listed naturally spawning populations.” Under the current system of ESA 

administration, NMFS and FWS have the responsibility to determine whether or not 

management measures are “adequate” to protect ESUs. In the absence of approved recovery 

plans and a quantitative risk standard, plus a comprehensive methodology for assessing risk and 

factoring the various uncertainties into that assessment, agencies have considerable latitude in 

implicitly defining “adequacy” in their jeopardy findings and the annual guidance they provide 

for harvest management. That discretion, however, carries the obligation to disclose and fully 

document the data and methods employed in their analyses in Biological Opinions. This 

discretion also creates more scope for litigation. NOAA Fisheries issued a report in November 

2004 describing its approach to establish jeopardy standards for ESA-listed salmon.16 Section 4b 

of this report provides comments and perspectives on the adequacy of the scientific analyses 

underlying jeopardy standards for harvest management. 

In addition to ESA jeopardy standards, harvest management is also guided by statute (such as the 

National Standards contained in the Magnuson-Stevens Fishery Conservation and Management 

Act), legal standards (e.g., Indian treaty fishing rights providing for conservation of individual 

stocks and allocation of harvestable surpluses), and administrative processes such as those 

employed by the PFMC. The PFMC provides an annual preseason assessment of projected 

fishery impacts in Appendix A of its Preseason Report III for ocean salmon fisheries as part of 

the administrative record. Finally, challenges to the adequacy of plans in protecting ESA-listed 

populations can be filed in judicial proceedings. 

When evaluating the adequacy of harvest management actions in protecting ESA listed 

populations, it is important to understand that harvest is related to productivity through complex 

interactions of escapement with spawning success, competition, and predation, and that harvest 

is only one source of mortality. It is one of the “4Hs” commonly used to describe the primary 

influences that affect recovery. Actions taken to increase freshwater productivity (increase 

freshwater productivity via enrichment, or decrease competition between hatchery and wild fish, 

etc.), and actions taken to reduce mortalities related to the other H’s, affect the determination of 

what is an appropriate harvest level (i.e., sustainable or appropriate for restoring abundance). 

Consideration of the 4Hs reflects social policy determinations that involve notions of fairness, 

legal obligations, and choices that pit long-term conservation of stocks and habitat against shortterm harvest, power generation, agriculture, and other economic use of natural resources. 

A comprehensive and consistent decision framework that integrates all sources of mortality and 

sources of improved productivity and their associated uncertainties would be extremely useful 

when addressing the role of harvest management in conserving ESUs. Significant technical and 

institutional challenges would have to be addressed to establish such a framework. For example, 

technical challenges to be addressed would include: uncertainty in implementation of harvest 

management; scientific uncertainties in quantifying relationships between habitat conditions and 

productivity, and interactions between hatchery and wild fish; and the role of dam passage on 

survival and productivity. Institutionally, the diffusion of responsibilities for listing, science, 

sustainable fisheries, recovery planning within agencies, and eventually enforcement of recovery 

 

16Dygert, P. and S. Bishop. 2004. Report Prepared by Northwest Region, Sustainable Fisheries Division, NOAA

Fisheries. November 16, 2004. 

 

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ISAB 2005-4 Harvest Report 

actions, coupled with exploitation by fisheries regulated by multiple jurisdictions, poses 

formidable difficulties for consistency and coordination. 

The current focus on “adequacy” should be squarely placed on whether management measures 

are sufficient: to make predictable progress towards population recovery on the basis of those 

factors that are reasonably well-characterized; to maintain options and avoid irreversible damage 

to the capacity of ESA-listed populations to recover over time; and, to monitor the status of listed 

populations and identify key uncertainties. Because of the potential for rapid adjustment of 

harvest, and given the existence of systems that collect and analyze data in a timely manner to 

monitor impacts, harvest management measures can be adjusted both annually and in-season. 

The ability for managers to directly intervene, however, carries the liability that harvest 

management may be called upon to bear a greater share of the conservation burden in a crisis 

situation, particularly for protecting populations in listed ESUs. It is essential to note, though, 

that if the predominant limiting factor to recovery is not harvest, then those other factors must be 

addressed, or the value of reduced harvest will be temporary and not sufficient for recovery.

3. What are the consequences of mark-selective fisheries on the accuracy and precision of 

forecasting and on consideration of harvest regime options (NOAA Fisheries, NWPCC, 

and CRITFC question)? Are there practical measures that could be implemented in 

the short- or long-term to address the challenges posed by mark-selective fisheries 

(NOAA Fisheries, NWPCC, and CRITFC question)? 

Generally, mark-selective fisheries can be expected to increase uncertainty in harvest 

management of natural (unmarked) salmons, in terms of both precision and bias. The 

consequences of mark-selective fisheries are situational. Depending on the location and intensity 

of harvest, mark-selective fisheries might or might not have a significant effect on a variety of 

harvest management tools, such as in-season run size estimation and forecasting. The reports of 

the Pacific Salmon Commissions Selective Fishery Evaluation Committee identify and discuss 

potential effects of mark-selective fisheries on harvest and management tools (ASFEC 1995). 

Additionally, a report in preparation by the Expert Coded Wire Tag Panel convened by the 

Pacific Salmon Commission in June 2004 is expected to address this issue in depth. 

Potential practical measures that could be employed to compensate for increased uncertainty 

caused by mark-selective fisheries center on two areas: (1) increasing investment in sampling 

and monitoring programs to improve the capacity to gather the data necessary to assess the 

effectiveness of mark-selective fishing in accomplishing resource management objectives; and 

(2) revising management targets or constraints to adjust for increased uncertainty, e.g., jeopardy 

assessments could be conditional, depending upon whether or not mark selective fisheries are 

relied upon to constrain harvests of unmarked fish. Currently, the magnitude of mark-selective 

fisheries is determined by the impact limits allowable on natural stocks under non-selective 

fishing; those limits are not reduced to compensate for increased risk due to uncertainty. 

Two other important factors should be recognized when dealing with mark-selective fisheries. 

First, the capacity to conduct mark-selective fisheries depends upon continued investment in 

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ISAB 2005-4 Harvest Report 

hatchery production and mass-marking. There are significant ecological risks17 associated with 

developing fishing strategies that depend on sustained hatchery production, and these should not 

be cavalierly dismissed (e.g., density-dependent competition and/or predator dynamics involving

interactions of hatchery and naturally produced juveniles). Second, the costs of mass marking, 

double index tagging, and sampling/reporting programs for catch and escapement will likely 

strain agency budgets and result in reduction of services or other programs, such as data 

collection, research, or enforcement. If investments are not made to improve sampling and 

reporting programs, increased management uncertainties will result from reduced quality of data. 

Although the potential benefits of mark-selective fishing are intuitively appealing, the 

effectiveness of this tool in addressing conservation needs for depressed natural populations 

needs to be evaluated. There are critical uncertainties that would benefit from additional 

research, particularly in the following areas: 

• the ability of double index tagging to provide reliable estimates of mortalities of 

unmarked fish in practice; 

• the variability and magnitude of release mortality rates in relation to the gear employed 

and fleet behavior; 

• quantification of drop-off mortality losses (i.e., hooked but not handled); and 

• biases that could be introduced by multiple encounters (fish being hooked again after 

release). 

4. Are analytical tools sufficient to adequately track future harvest rates (NWPCC and 

CRITFC)? If not, what tools or performance standards will be most effective for 

managing fisheries (CRITFC, NWPCC)? Are there opportunities to use PIT tags to 

improve management capabilities and reduce uncertainty (NOAA)? 

Harvest management of Columbia River salmon involves a number of data collection systems 

that monitor impacts and analytical tools to evaluate results. For example, spawning escapements 

and dam counts provide data on escapements past fisheries; differences in run-timing (e.g., 

spring vs. summer vs. fall Chinook), skin coloration (e.g., URBs vs. tules), and size (e.g., 

distinguishing between A & B Run steelhead) are used to differentiate populations; run 

reconstruction and CWT analysis are employed to provide insight into patterns of fishery 

exploitation, abundance forecasting employ statistical regressions based on sibling relationships; 

modeling is employed to facilitate planning of fisheries to constrain impacts; Passive Integrated 

Transponder (PIT) tags provide information on migration rates and dam passage mortalities; etc. 

Certainly, there are several areas where the scientific basis for some of the tools and methods is 

unclear/suspect and there is undoubtedly much room for improvement (some of these questions 

are noted in the last column of Appendix B of this report and in the discussion of the 

management of B run steelhead in Appendix C). The determination of “adequacy” of these tools 

is situational and beyond the capabilities of ISAB to evaluate in this report. An independent 

analysis would be helpful to provide an in-depth evaluation of current tools and methods and to 

develop recommendations for improvement. At a minimum, it would be beneficial for the users 

of these tools to themselves undertake a systematic effort to fully document and explain these 

methods, and to make this documentation readily accessible. 

 

17 For example, predator attraction, proliferation of disease, limits to carrying capacity, detrimental effects of 

inbreeding of hatchery brood stocks, and interbreeding between hatchery and wild populations. 

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To-date, much of the information employed for the management of Columbia River salmon was 

derived from analysis of CWT data. Analysis of CWT recovery data must frequently involve 

statistical inference because this technology is based on group marking and single recoveries 

(sacrificial sampling is required to recover data) of individual members of a group. These 

characteristics require assumptions and interpretation to address questions of interest to 

managers and researchers. For example, migration routes and patterns are inferred by the timing, 

location, and frequency of recoveries. 

CWT technology is over thirty years old. Newer technologies are now available and capable of 

providing data and information that is unattainable from CWTs. One of these technologies is the 

PIT tag, a tiny identification chip (about the size of a grain of rice - 11 mm by 2mm) that can be 

injected into fish for permanent, unique identification. PIT tags can be read without killing the 

host. This provides opportunities for research projects to generate data that enable fishery 

managers to gain insight into questions that have long evaded researchers. Since each fish carries 

a unique code that can be read electronically in proximity to an antenna, PIT tags can potentially 

provide data for estimation of natural and release mortality rates, migration patterns and rates, 

and growth rates. Additionally, since PIT tag data can be recovered without mutilating the fish, 

market values of the fish can be preserved, and barriers to processor and fisherman cooperation 

can be eliminated. While PIT tag data is now becoming more readily available for harvest 

management, designs for PIT tag deployment and sampling for recoveries to address various 

questions are still under development. Because mortality rates are high, and tag recovery rates 

are low, effective designs generally require large numbers of tags and a concerted tag recovery 

effort. For this reason, effective programs require broad consensus about design. 

Numerous research studies involving PIT tag technology are being undertaken. PIT tag readers 

are being deployed at passage facilities at several dams in the Columbia River system. In the 

field, PIT tag readers are being installed at hatcheries to recover data on returning adults and in 

small streams to evaluate their potential utility in monitoring movement of juveniles and adults. 

So far, the principal use of PIT tags in the Columbia has been to monitor the magnitude and 

sources of juvenile mortality and the migration patterns of juvenile fish.18 Fish from some PIT 

tag experiments are now beginning to return as adults.19 The Pacific States Marine Fisheries 

Commission maintains a PIT Tag Operations Center and hosts a PIT tag Information System

database (PTAGIS, http://www.psmfc.org/pittag/). Considerable investments are being made to 

 

18 NOAA has provided internet access to an example of PIT tag application on Snake River fish

http://www.nwr.noaa.gov/1salmon/salmesa/pubs/pittag.html. “The PIT-tag data from 1994 through 1995 show that 

juvenile spring/summer chinook survival through each project (dam and reservoir) is about 90 percent. At that rate, 

survival through the entire system of eight dams and reservoirs is roughly 50 percent. The picture is different for 

Snake River fall chinook. They suffer a per-project mortality of about 80 percent, which translates into a system

survival of 17 percent as they complete their downstream journey.” A sidebar on the same webpage describes 

results of studies regarding the effects of flows on survival of Chinook – “For spring/summer chinook, studies since 

1994 show that juveniles migrating in years with higher flows survive at a higher rate than juveniles migrating in

years with lower flows. There appears to be little relationship, however, between flows and survival within a given

year. The picture is different for fall chinook, which migrate during the summer when flows are low and water 

temperatures high. Here there is a much stronger correlation between increased flows and increased survival both 

within and between years.” 19 The Fish Passage Center provides internet access to adult return PIT tag data at 

http://www.fpc.org/adultsalmon/adultPITtag.html. 

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employ this technology extensively in the Columbia River system. There is no guarantee that the 

spatial distribution of PIT tagged hatchery and wild anadromous fish for experiments will meet 

management needs in the future. The region should begin planning of long term monitoring of 

life history parameters, including harvest mortality, of hatchery and wild fish by use of PIT tags. 

The potential application of PIT tags in harvest management is being considered by the CWT 

Expert Panel of the Pacific Salmon Commission, which will be reporting in the summer 2005. 

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7. Background Sections 

7a. Sustaining Diversity 

Pacific salmonids do not exist as a single homogeneous population, but rather as mosaics of 

discrete spawning aggregations (Ryman and Utter 1987, Fraser and Bernatchez 2001). This 

mosaic of sub-groups (sub-populations) is often referred to as a metapopulation. The 

subpopulations within a salmon metapopulation are believed to be differentiated from one 

another to varying degrees through adaptation to their local environments, yet linked through 

occasional gene flow (Hallerman 2003). This genetic and life history diversity within and among 

subpopulations is the currency that allows the species to adapt to the changing environmental 

conditions of the future (Noss 1990). A key feature of the metapopulation concept is that if one 

of the local populations becomes extirpated, it could be recolonized naturally from one of the 

other subpopulations in the mosaic. Furthermore, within a metapopulation, it is likely that some

subpopulations could serve as key or core source populations for such recolonization. The core 

source subpopulations could change over time in response to habitat alterations, overfishing, 

climate change, etc. Our current understanding of metapopulations represents a refinement of the 

concept of fish stocks (Berg 1981) that has been used in shaping harvest management decisions 

over the past half-century. 

 

Historically, harvest management focused both on the biomass production from, and the 

protection of, major populations (stocks) of single species (Cushing 1968, Hyatt and Riddell 

2000). Referred to by fishery biologists as the Stock concept, this subdivision of species into 

populations for management was a major advance in Pacific salmon harvest decision-making 

(Morishima and Henry 2000). Unfortunately, this approach assessed exploited populations in 

isolation from their genetic processes and demographic history (Riddell 1993, Hyatt and Riddell 

2000). Often, populations that were either low in numbers and/or low in productivity 

commingled with larger or more productive stocks. As the biology of Pacific salmon has become

better understood, management strategies now put more emphasis on protecting the diversity of 

these populations and not just the total production of salmon. One challenge for setting harvest 

policy today is devising regulations that permit harvest but at the same time protect dwindling 

and, in some cases, federally protected fishes. 

 

In the Columbia River, salmon harvest in a number of fisheries is limited by regulations designed 

to protect weaker stocks. Fall fisheries for both Chinook and coho salmon can be constrained by 

regulatory protections for ESA listed Snake River fall-run Chinook. Overall, a 32% impact is 

permitted on fall Chinook, which includes the productive “upriver bright” salmon from the 

Hanford reach along with the ESA listed Snake River population. In the fall of 2004, two lower 

Columbia River mainstem gillnet fisheries were cancelled when the total September allocation of

fall Chinook was nearly reached. Fishermen had to forego catching hatchery and unlisted midColumbia fall Chinook to preserve the opportunity to fish for coho salmon in October – because 

that fishery incidentally takes the remainder of the fall Chinook allocation (CBB 2004). 

The importance of maintaining diversity between spawning populations is not just an issue of 

conserving genetic diversity. Diversity is related to sustaining production and the full utilization 

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of freshwater habitats. Stocks that are weak (i.e., lower productivity) at one point in time may 

become productive during other times and visa versa, and evidence has accumulated that 

protecting currently weak stocks is a prudent management approach to protect future production. 

A good example is the Bristol Bay, Alaska stock of sockeye salmon, for which record catches 

have been sustained over the past 20 years (Hilborn et al. 2003). This fished stock, however, is 

believed actually to be composed of hundreds of discrete populations, each of which may be 

spawning and rearing in a specific, different habitat. Hilborn et al. (2003) argue that this 

aggregate of Bristol Bay sockeye has maintained a productive fishery over a period of 

appreciable change in environmental conditions due to this diversity of populations and that 

some were likely minor producers during one period but dominated during others. Maintaining 

the diversity of sockeye populations through time has allowed different populations to sustain the 

fishery at different times and conditions. 

The biodiversity inherent in the salmon populations of the Columbia River Basin (CRB) is under 

active and continuing study (Brannon et al. 2002, Myers et al. 2003). Currently, salmonids 

within the CRB are categorized as belonging to one of several Evolutionarily Significant Units 

(ESUs), i.e., a population or assemblage of populations that are substantially reproductively 

isolated from other con-specific populations and that represent an important component of the 

evolutionary legacy of the species (Waples 1991, 1995). There is also an increasing 

understanding that these ESUs are further subdivided into numerous demographically 

independent populations. For example, the Willamette/Lower Columbia Technical Recovery 

Team (WLC-TRT) concluded that historically there were likely at least 30 demographically 

independent Chinook salmon populations in the Lower Columbia River ESU (21 fall/late fall run 

and nine spring run) and seven in the Upper Willamette ESU. For steelhead, the WLC-TRT 

concluded that there were likely 24 populations in the Lower Columbia River ESU (18 winter 

run and six summer run) and five populations in the Upper Willamette ESU (Myers et al. 2003). 

To take the genetic subdivision of CRB salmonids (whether defined as stocks, ESUs, or 

metapopulations) into account in their harvest management, one must determine how the harvest 

of that species within a mixed stock fishery impacts not only the viability of the species as a 

whole, but also the viability of each of the component subpopulations individually. For example, 

if related groups of returning adults migrate together and not randomly, harvest may not be 

uniform across all subdivisions. As a result, one or two of those groups (i.e., the individual 

subpopulations within a metapopulation) might be overfished relative to desired harvest targets, 

perhaps to an extent that successful reproduction of that subpopulation would be jeopardized for 

that year. Unfortunately, salmon harvest today consists of such mixed-stock fisheries. 

Furthermore, at this time we do not fully know the delineation of the various component 

populations that make up the greater metapopulations within each ESU, much less how these 

populations are connected via gene flow. We also do not know which populations can or cannot 

serve as key source populations for recolonization. These information gaps will continue to be a 

major obstacle to establishing effective conservation programs for our dwindling salmonid 

populations. The use of newly developed technology may, however, allow us to fill at least some

of those gaps. 

Given the emerging understanding of the spatial organization of Pacific salmonids and the 

importance of diversity in production and adaptability, harvest policy needs to go beyond setting 

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ISAB 2005-4 Harvest Report 

“stock”-wide escapement goals and also incorporate a goal to conserve the biodiversity inherent 

in each CRB salmonid species, i.e., setting harvest goals for each of the individual subunits 

within the legally defined ESU. 

The ISAB notes that the metapopulation concept summarized above addresses only a single 

species. Each species, though, is but one component of the larger ecological community 

involving many species. In the future, a major challenge for harvest management will be to 

incorporate our growing understanding of multi-species interactions and ecosystem linkages into 

harvest and conservation actions (Hyatt and Riddell 2000).

7b. Freshwater Ecosystems 

There has been increased interest in the importance of marine-derived nutrients from salmon 

eggs and carcasses in supporting the food web productivity of freshwater habitats where salmon 

spawn (Stockner 2003), and recent evidence suggests that establishing escapement goals should 

include a consideration of the need for salmon carcasses to maintain the productivity of 

freshwater environments. Chinook, chum, coho, pink and sockeye salmon die after spawning, 

and a high proportion of steelhead also expire. The carcasses and reproductive products left by 

these fish can represent a substantial source of nutrients and organic matter for Pacific Northwest 

watersheds (Larkin and Slaney 1997, Naiman et al. 2002). This material is readily incorporated 

into the stream or lake food web (Kline et al. 1990, 1993, Bilby et al. 1996, Johnston et al. 1997), 

provides a food source for wildlife (Cederholm et al. 1989), and may also provide nutrients for 

plants in the riparian area (Helfield and Naiman 2001, Bilby et al. 2003). The significance of this 

relationship to the establishment of appropriate escapement goals and the consequences for 

harvest levels have increasingly become topics of discussion in the region. 

Much about the process of nutrient transfer from carcasses to aquatic and riparian plants and 

animals is still poorly understood. However, the potential significance has long been recognized 

by both the scientific community (Juday et al. 1932) and in more popular literature. 

 

“The death of a salmon is a strange and wonderful thing, a great gesture of abundance. 

Yet the dying salmon are not wasted. A whole natural economy is built on their bodies. 

Bald eagles wait in the trees, bears hunt in the shallows and along the banks, mink and 

marten and coons come nightly to the feast. All through the winter mallards and 

mergansers feed in the eddies, and in freshet time, the herring gulls come in to plunge 

down on the swifter water and pick up the rotting drift. Caddis larvae and other 

carnivorous insects crawl over the carcasses that are caught in the bottoms of the pools 

or against the rocks in the eddies. The stream builds its fertility on this death and readies 

itself to support a new generation of salmon.” (Haig-Brown 1946).

Scientists have also long recognized the importance of nutrients from salmon carcasses to 

freshwater production in lakes used by sockeye salmon, and subsequent research has supported 

these earlier findings. Sockeye salmon returning to Lake Illiamna in southwestern Alaska deposit 

7x107

 kg of nitrogen (N) and 3.3x106 kg of phosphorus (P) annually (Naiman et al. 2002). In 

contrast, the N and P exported from the lake by smolts represent only about 8% of that 

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contributed by the adult salmon. Spawning salmon appear to be a net importer of nutrients to 

nearly all sockeye rearing lakes. 

Many sockeye rearing lakes are nutrient limited (Hyatt and Stockner 1985, Gross et al. 1998). 

Thus, the nutrient subsidy provided by spawning salmon can stimulate primary (vascular plants 

and algae) and secondary (animal) production. This nutrient subsidy can be substantial. Juday et 

al. (1932) estimated that sockeye salmon transported in excess of 2 million kg of organic matter 

and 5,000 kg of phosphorus (P) to the Karluk River system in Alaska in an average year. 

Reduction of the sockeye salmon returning to Karluk Lake, Alaska, led to substantial reductions 

in P availability and reduced primary and secondary production (Schmidt et al. 1998). Reduced 

productivity causes a depensatory effect on salmon populations: fewer spawning adults result in 

lower primary and secondary production, which reduces the growth and survival of juvenile 

salmon, which can lead to fewer returning adults, causing a downward productivity spiral. 

Scientific interest in the role salmon play in the nutrient dynamics of freshwater ecosystems has 

been spurred by the application of stable isotope analysis. Salmon returning to spawn contain 

higher proportions of the heavier isotopic form of nitrogen (N15) and carbon (C13) than is found 

in N and C in freshwater ecosystems from other sources. As a result, the ratios of stable isotopes 

to normal atomic weight elements can be used to track the movement of marine-derived N and C 

through the food web of lakes or streams. Isotopic ratios also provide an indication of the 

proportion of the nutrients of aquatic ecosystems provided by spawning salmon. 

The application of stable isotope technology has enabled the reconstruction of long-term sockeye 

salmon abundance for some lakes in Alaska (Finney 1998). Some of the isotopically enriched 

nitrogen deposited by spawning sockeye becomes incorporated into the lake sediments. The 

variation in the isotopic ratios of sediment strata in the lakebed surface has been used to estimate 

historic abundance of salmon. The fossilized remains of plankton also are deposited, enabling the 

association of historic escapement levels with the attributes of the lakes planktonic community. 

These analyses have demonstrated that the advent of commercial fishing in Alaska in the early 

20th century corresponded with a marked reduction in the deposition of marine-derived nutrients 

in some Alaskan lakes (Finney et al. 2000). There was also an increase in the abundance of 

benthic diatoms, suggesting a decrease in the production of algae suspended in the water column

(phytoplankton). Reduced phytoplankton production may have been caused by higher 

consumption by zooplankton populations, which increased due to reduced predation by the 

sockeye. Reduced phytoplankton density would increase water clarity, thereby increasing light 

for the benthic diatoms. 

In addition to fishing, other factors can limit the number of salmon returning to spawn, and 

where the cumulative effects of harvest and these other factors reduces escapement to very low 

levels there are important implications for nutrient dynamics and salmon productivity in 

freshwater ecosystems. Scheuerell et al. (2005) used a mass balance approach for phosphorus to 

estimate that the historical recruitment of P by adult Chinook salmon to the Snake River basin 

was about 70 times the current level, and furthermore that in several recent years the export of P 

from the basin by smolts actually exceeded the amount brought in by spawners. These authors 

stated that the loss of marine-derived nutrient subsidies from adult salmon has resulted in a 

marked shift in freshwater productivity, exacerbating strong density-dependent survival rates of 

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ISAB 2005-4 Harvest Report 

juveniles. 

Relatively little quantitative information on the nutrient contribution by salmon to stream

ecosystems existed until fairly recently. Application of stable isotope analysis has demonstrated 

that the nutrient subsidy provided by spawning salmon can account for a substantial proportion 

of the nutrients in the biota of stream systems, including juvenile salmonids. Nitrogen and carbon 

contained in resident rainbow trout in a southeast Alaska stream were derived almost entirely 

from the large numbers of pink salmon that spawned at the site (Kline et al. 1990). Juvenile coho 

salmon, cutthroat trout, and steelhead in a tributary of the Snoqualmie River, Washington, 

obtained as much as 40% of the carbon and nitrogen in their muscle tissue from the carcasses of 

coho salmon (Bilby et al. 1996). Johnston et al. (1997) found a relationship between the 

proportion of marine-derived nitrogen in aquatic insects and the density of spawning sockeye 

salmon in tributaries of the Stuart River in interior British Columbia. A similar relationship has 

been reported for juvenile coho salmon in western Washington (Bilby et al. 2001). 

The nutrient subsidy provided by spawning salmon can have an impact on stream productivity. 

Elevated primary production has been attributed to nutrients from salmon carcasses in a number 

of oligotrophic systems. Kokanee salmon (landlocked O. nerka) carcasses stimulated algal 

production in a small tributary of Lake Tahoe, California-Nevada (Richey et al. 1975), and the 

addition of 25 Chinook salmon carcasses to a tributary of Lake Superior, Minnesota, resulted in 

increased algal growth on the streambed (Schuldt and Hershey 1995). The increase in primary 

production and the availability of carcasses and eggs as a food resource can stimulate 

invertebrate production (Piorkowski 1995, Minikawa 1997, Wipfli et al. 1998). 

Juvenile salmonids readily ingest eggs deposited by spawning salmon and flesh from 

decomposing carcasses. During the period of sockeye salmon spawning in small streams of the 

Wood River drainage in Alaska over 90% of the stomach contents of char (Salvelinus sp.) and 

rainbow trout consisted of salmon eggs and flesh (Eastman 1997). Char and trout grew rapidly 

while carcasses were present, with one individual increasing 58% in body weight in 36 days. 

Artificially increasing the availability of salmon carcass flesh and eggs by adding carcasses of 

coho salmon to a small stream in southwestern Washington doubled the growth rate of juvenile 

coho salmon relative to a nearby stream reach with a low availability of carcasses (Bilby et al. 

1998). Higher invertebrate abundance in streams with spawning salmon (Minikawa 1997) also 

can enhance food availability for juvenile salmon. The importance of nutrient availability during 

summer was demonstrated by nitrogen and phosphorus additions to the Keogh River on 

Vancouver Island (see Stockner 2003). A slight increase in the concentrations of these elements 

produced dramatic increases in the abundance and growth rate of juvenile coho salmon, 

steelhead and Dolly Varden char (Johnston et al. 1990). 

There is increased interest in developing escapement goals and harvest management strategies 

that account for nutrient delivery by adult salmon to freshwater ecosystems (Larkin and Slaney 

1997). However, there is little information from which to determine escapement levels 

appropriate to satisfy the trophic needs of aquatic and terrestrial biota. Ideally, estimates of the 

number of spawners needed for this function would be determined experimentally by controlling 

escapement levels and monitoring survival of progeny. Escapement levels for each stock would 

be varied through time and the impact on system productivity evaluated. However, conducting 

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these long-term experiments on multiple species and populations would be a formidable task and 

would not provide usable results for many years. 

Two alternative approaches for incorporating salmon nutrients into escapement goals have been 

suggested. Michael (1998) estimated the amount of salmon carcass tissue required to meet the 

dietary needs of juvenile salmon, insectivorous birds and bald eagles for the Skagit River, 

Washington. In this exercise, he assumed that all food consumed by the fish and birds was 

supported by salmon carcasses deposited in the system. He determined that current salmon 

escapement goals for the Skagit would need to be doubled to provide this level of trophic 

support. However, salmon are not the only source of nutrients and organic matter for these 

organisms. A thorough understanding of the nutrient dynamics and energetics of a system and 

the contribution salmon carcasses make to these processes would be required to use a this type of 

approach to establish escapement goals. 

Another alternative that has been proposed is based on a relationship between spawner density 

and the proportion of marine-derived N in the tissues of juvenile fish (Bilby et al. 2001). Ideally, 

this type of relationship would enable a “saturation level” for marine nutrients in a watershed to 

be established and escapement goals set accordingly. A “saturation level” would correspond to a 

spawning escapement above which additional spawners would not contribute significantly to 

aquatic and riparian ecosystem productivity. This relationship was examined for coho salmon in 

approximately 20 watersheds in western Washington (Bilby et al. 2001). N stable isotope levels 

in pre-smolt coho salmon, captured in late winter, were related to the amount of carcass tissue 

deposited at the location where the young fish was captured the previous autumn. N stable 

isotope values in the juvenile coho increased with increasing carcass deposition up to a level of 

approximately 0.15 to 0.20 kg/m2

 of stream surface area (approximately 80 – 150 salmon/km). 

However, this approach does not consider the full range of ecological interactions potentially 

associated with carcass deposition. It does not address carcass use by wildlife or the use of 

nutrients from spawning salmon by riparian vegetation. The relationship between carcass 

deposition and proportion of salmon-derived nutrients in the aquatic system may differ for 

species other than coho salmon. The relationship can also be obscured by temporal variability in 

environmental conditions other than nutrient availability. Nonetheless, this approach does merit 

further investigation as it is relatively easy to apply and broadens the scope of ecosystem

processes that are considered in setting harvest levels for salmon. 

Despite the incomplete knowledge of the role salmon-derived nutrients play in the trophic 

support of freshwater ecosystems, sufficient study on this subject has been completed to suggest 

that the value of salmon to maintaining freshwater ecosystem productivity should not be ignored 

in the harvest planning process. Application of traditional methods of setting harvest levels and 

escapement goals without due regard for the ecological role salmon play in watershed processes 

may have contributed to historic declines in stock productivity and may be hindering efforts to 

restore the productivity of freshwater habitats. 

An improved appreciation of the ecological role of spawning salmon can assist harvest planning 

in several ways. First, it is important to consider the entrainment of marine-derived nutrients 

from all species using a watershed. There is no evidence that food webs depend on only one 

species and ample evidence that strong inter-specific dependencies exist among salmon (e.g., 

juveniles of one species are affected by spawner abundance of another species). Factoring 

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considerations of marine-derived nutrients into escapement targets should include all species 

returning to a watershed. Second, the ISAB is not aware of any evidence that “over-escapement” 

leads to reduced population productivity or watershed harm (Walters et al. 2004); in fact, there 

are a number of processes that can store marine-derived nutrients (e.g., in riparian plant tissues) 

for future ecosystem benefits. We suggest that the concept of over-escapement, if limited to the 

notion of spawning adults in excess of the apparent habitat capacity, overlooks a positive 

feedback between the abundance of returning adults and freshwater productivity that is of 

fundamental long-term importance. Finally, we caution that replacing natural production of 

salmon with hatcheries can create an ecological dead end that diverts marine-derived nutrients 

and organic matter from where they are needed most (the watershed) to where they are needed 

least (the hatchery). Further, this diversion of nutrients (assuming hatchery carcasses are not 

deliberately replaced in natural streams) may be exacerbated by competition between hatcheryproduced salmon and wild fish for limited food resources. 

7c. The Hatchery Paradigm and Ocean Carrying Capacity 

Techniques to spawn Pacific salmon ova and hatch and release fry were refined in the late 1880s, 

about the same time salmon harvest peaked on the Columbia River, and coincident with 

degradation of freshwater habitats due to logging. This technological advance permitted juvenile 

salmon produced in hatcheries to be released to complete their life-cycle in the ocean, with the 

intention of providing fish to harvest. Hatchery production was initially used to avoid imposition 

of regulatory restrictions on land-use and fishing practices. This management strategy was based 

on the belief that early life-stage mortality of the large numbers of salmon eggs and fry produced 

annually in freshwater was the main factor that limited the numbers of adult salmon available for 

harvest. Later in the 20th century hatchery production was employed to attempt to mitigate for 

habitat lost following dam construction. Currently selective harvest of hatchery-origin fish is 

promoted in an attempt to permit harvest to continue despite protection of listed species. 

As many as 6.1 billion salmon smolts are released each year from hatcheries into the Pacific 

Ocean (Beamish et al. 1997). In the Columbia River over 200 million hatchery-origin smolts are 

released each year. When combined with naturally produced juveniles, the total smolt migration 

into the ocean from the Columbia River may exceed the numbers migrating before European 

settlement and hydrosystem development (HSRG 2004, NWPPC 1986). 

Ever-increasing production of young salmon has not proven to be a panacea, however, as shown 

by the coastal coho fishery. In the 1960s and early 1970s improvements in fish husbandry led to 

a corresponding improvement in coho salmon survival following their release from coastal 

hatcheries in Oregon (Lichatowich 1993, Bottom 1999). Between 1960 and 1966, coho salmon 

egg collections, smolt releases, and the commercial catch increased proportionately (Lichatowich

1999). Soon thereafter however, adult coho production fluctuated erratically and with little 

apparent relationship to the abundance of smolts released. In 1977 commercial landings of coho 

salmon abruptly collapsed from a high of 3.9 million fish to only a million fish. Salmon smolts 

were being produced by hatcheries, circumventing freshwater mortality, when this collapse 

occurred. Consequently, the collapse generated interest in the role of the marine environment in 

fluctuations in adult salmon numbers. Over the last quarter century evidence has accumulated 

that short term (year-to-year - El Nino and La Nina) and intermediate term (decade-to-decade - 

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Pacific Decadal Oscillation) cycles in marine environment productivity are important 

determinants of salmon abundance. There is general scientific agreement that the carrying 

capacity of the ocean is not limitless or fixed, but is dynamic and fluctuating. 

Incorporating the concept of a limited and variable ocean capacity into a scientific framework 

guiding salmon management raises an important question. Are the large numbers of hatchery 

smolts that are being released to augment harvest reducing the survival and abundance of 

naturally produced smolts entering the ocean? 

Formerly, salmon production had been assumed to be independent of density. Salmon were 

believed to use only a small fraction of the food and space available in marine ecosystems. 

Recent observations challenge this assumption and raise the specter of density dependence. 

Population sizes of animal species, including salmon, can have density-dependent and densityindependent causation. Typically, density-dependent factors involve the size of a population and 

the biological interactions like diseases, competition, and predation. Density-independent 

mortality is not associated with population size and involves limiting environmental factors such 

as annual climate variability and pollutants. In actuality, animal populations are affected by both 

density-dependent and independent processes, but the relative importance and scale of each 

effect is of interest. In salmon management, the choices and success of management strategies 

will be affected by the nature of population regulation. If the sources of mortality for salmon in 

the ocean have a substantial density-dependence, then releases of hatchery-origin juvenile 

salmon could increase mortality of natural-origin juveniles. 

Formal experiments quantifying density dependence in salmon are lacking. Graphical and 

correlation analyses showing negative relationships between catch records, ocean survival, and 

hatchery release numbers and recent declines in age of maturity and size at age of salmon species

are cited to support the thesis that hatchery programs may impact survival and growth of naturalorigin salmon under some circumstances. In the Columbia River, smolt-to-adult returns of 

natural Chinook populations were negatively affected by large releases of hatchery smolts during 

periods of poor ocean productivity (Levin et al. 2001). Ruggerone and Goetz (2004) compared 

survival, growth, and maturation of sub yearling Chinook salmon released from Puget Sound 

hatcheries in years with and without juvenile pink salmon production. During years of abundant 

pink salmon production Chinook salmon survival was reduced 62%. They report a similar 

pattern in lower British Columbia streams where pink salmon are abundant. The pattern was not 

detected in Chinook salmon originating from streams along the Washington coast and lower 

Vancouver Island, where pink salmon are largely absent. Inter-specific competition with Asian 

origin pink salmon (O. gorbuscha) reduces the survival, abundance, and size of Bristol Bay 

sockeye salmon (O. nerka) (Ruggerone et al. 2003). 

Beamish et al. (1997) conclude that ocean carrying capacity limits coho and Chinook stocks in 

Canada, Washington, Oregon, and California, because catches of coho and Chinook have 

steadily declined despite the release of hatchery smolts (Figure 7c-1). They base their conclusion 

on the assertion that catch is a reasonable index of abundance (Beamish et al. 1995, Beamish et 

al. 1997). Caution is warranted in attributing this relationship to limits on ocean carrying 

capacity/density dependence. During the time period analyzed, there were major changes in 

mixed stock fisheries. Treaty fishing rights in the United States required stock-specific 

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conservation actions that resulted in restructuring and reducing ocean Chinook harvests and the 

Pacific Salmon Treaty resulted in limitations on coho harvests. The reduction in harvest 

attributable to reduction in fishing is not identified. The graphs would need to depict total 

production, not just catch. More recently though and based on direct sampling, Sweeting et al. 

(2003) have demonstrated that the percentage of hatchery-reared coho salmon in the Strait of 

Georgia, BC, has increased from nearly 0% in the early 1970s to more than 70% by 2001, during 

the development of the Canadian Salmonid Enhancement Program. 

Figure 7c-1. (a). The decline in Chinook catch from southern British Columbia, Washington, and

Oregon in relation to hatchery production. (b). The decline in coho catch from southern British 

Columbia, Washington, and Oregon in relation to hatchery production. Catch (); Hatchery 

Releases (). From Beamish et al. 1997. 

Further, Hilborn and Eggers (2000, 2001) concluded that in Prince William Sound, Alaska, 

release of nearly 500 million pink salmon fry from hatchery production has increased total 

production by at most only 2 million fish, and been associated with a decline in escapement of 

wild salmon. Instead of augmenting the fishery, they believe hatchery releases have largely 

replaced natural production. From the early 1950s through the late 1970s pink salmon catches 

were poor in Prince William Sound, averaging 3 million fish per year. In 1974 a hatchery 

program for pink salmon was begun and, since 1980 catches have averaged 20 million salmon; 

much of this production is hatchery produced. Hilborn and Eggers (2000) base their conclusion 

that these hatchery salmon have replaced rather than augmented natural production on the 

observation that catches of pink salmon in other Alaskan waters increased during this same time

period without substantial hatchery programs. 

There is not yet scientific consensus over density dependence of salmon production as it affects 

harvest. Wertheimer et al. (2001) question Hilborn and Eggers' conclusion. Wertheimer et al. 

(2001) believe, instead, that asynchrony of production across regions coupled with changes in 

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zooplankton (salmon food) and predator populations can account for the observations. Several 

investigations explored the evidence for density dependent marine mortality of coho salmon 

(Lichatowich 1993). Three of the six concluded there was evidence of density dependence; three 

did not. Unfortunately, the power of statistical tests to detect density dependence is typically low. 

In the tests to detect density-dependence in OPI coho, there was an 81% chance of incorrectly 

accepting the null hypothesis of density-independence, and a smolt release of 88 million 

individuals would have been needed to conduct an experiment with convincing statistical power 

(Peterman and Routledge 1983, Peterman 1989, cf Lichatowich 1993). 

Density may also affect size and age of maturation. Bigler et al. (1996) found that 45 of 47 North 

Pacific salmon populations, comprising five species from North America and Asia, are 

decreasing in average body size. They concluded that an inverse relationship between population 

abundance and average size during the period l975-l993 indicates that there is a limitation to the 

salmon carrying capacity of the ocean. They believed increases in hatchery programs in the l980s 

and early l990s have contributed to the ocean-wide reduced size of salmon. Size-selective 

harvest effects could also contribute to these trends (Hard 2004). 

A decline in body size due to density-dependence could be as important to recovery as decreased 

survival rates. A positive correlation between spawner size and survival of their progeny has 

been demonstrated in chum salmon (Helle 1989). Fecundity and egg size increase with increased 

female body size. Larger egg size may improve survival of incubating embryos and produces 

larger fry. Decreased fecundity reduces the number of gametes available to produce subsequent 

generations of salmon. 

While density dependence is not universally demonstrated statistically, there is increasing 

evidence of its effects on salmon abundance and growth. The last half-century of observations 

demonstrate that salmon harvests are not stabilized by the release of hatchery-origin salmon 

smolts. Research efforts are warranted to identify the magnitude of density dependence and the 

conditions under which it could impact the sustainability and recovery of Columbia River Basin 

salmon. Evidence of competition between salmon species originating from Asia and North 

America during marine residence suggests a need for international cooperation to determine the 

appropriate scale of the artificial production programs releasing juvenile salmon into the ocean. 

7d. Climate Change and Potential Salmon Harvest 

There is growing realization that global climate change and the climatic cycles of the ocean 

strongly affect salmon production, and that global climate change (i.e., a gradual warming of the 

earth’s global atmospheric-oceanic system) is occurring (IPCC 2001). Inclusion of climaterelated affects in salmon management could minimize over-fishing in times of predictably low 

salmon production thus reducing risk to stocks we wish to recover. Conversely, inclusion could 

also allow increased harvest when conditions are likely to be good for salmon production. 

Whether climate change has been induced by human activities or is a reflection of natural cycles, 

long-term climate change is to be contended with in planning the use of natural resources in the 

future. During the 20th century, the Pacific Northwest region of the United States experienced a 

warming of 0.8°C. Using output from eight climate models, Mote et al. (2003) projected a 

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further warming of 0.5-2.5°C (central estimate 1.5°C) by the 2020s, 1.5-3.2°C (2.3°C) by the 

2040s, and an increase in precipitation except in summer. The foremost regional impact of this 

general warming will be a reduction in regional snow pack, which currently supplies much of the 

water for ecosystems and human uses in the dry summers (Service 2004). 

Superimposed on this gradual change in the global system are shorter-term changes that are only 

now beginning to be understood and quantified. The year-to-year and decade-to-decade changes 

associated with the El Nino-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) 

cycles are generally felt throughout the Northwest despite significant annual differences in local 

climate (Mote et al. 2003). ENSO is an irregular oscillation of the tropical atmosphere and ocean 

with a period of 2-7 years (e.g., McPhadden et al. 1998). The more recently recognized PDO 

reflects monthly anomalies in Pacific sea surface temperature north of 20° latitude (Mantua et al. 

1997) and has an irregular period of several decades; in the 20th century it stayed in a cool or 

warm phase for 20-30 years at a time. It is the cause of the “regime shifts” that have received 

recent attention; cool from 1900-1925, warm 1925-1945, cool to 1977, and then warm to about 

1998 when the recent shift brought a cool phase again. Tree-ring data suggest that the PDO 

cycles have occurred at least since the 1600s (Gedalof and Smith 2001). Warmer, drier years 

often associated historically with El Nino (ENSO) and/or the warmer phases of the PDO tend to 

be associated with below average snow pack, low stream flow, and low flood risk in the 

Columbia River basin, and consequently below-average survival of most salmon stocks 

(Pulwarty and Redmond 1997). Alaska salmon tend to see the opposite trend, and British 

Columbia stocks are intermediate (Hare and Mantua 2000). 

The ENSO and PDO cycles can pass into and out of phase to interact with gradual global change 

and strongly affect the success of the Northwest’s natural resources (hydrology, forests, salmon; 

Mote et al. 2003). Historically, when ENSO and PDO have both been in their warm phase, the 

effects on snow pack, stream flow, floods, and salmon are all greatly reduced. Conversely, when 

both cycles are in phase for cool years, these features are all at extreme highs. When out of 

phase, the effects of either cycle are less extreme. 

The strong potential for gradual increases in regional temperature and losses of snow pack (and 

runoff water in spring and through the dry summers) is unlikely to aid productivity of Columbia 

River basin salmon stocks and their availability for harvest. The detrimental effect is likely to be 

seen primarily in the 2-3 decade periods of a warm PDO and accentuated when the 2-7-year El

Nino cycle hits its warm peaks. One study (Welch et al. 1998) suggested that the thermal 

suitability of most of the North Pacific for salmon could be eliminated in the worst years (most 

likely in the 21st century based on climate forecasts of the IPCC). Fortunately, we are currently in 

a cool PDO cycle with abundant salmon (Hare and Mantua 2000), although no one can tell with 

certainty when this cycle will revert to the warm period of the 1980s and 1990s when salmon 

stocks experienced sharp declines. 

The greater understanding of both gradual climate change and of the ENSO and PDO cycles (and 

perhaps other cycles not yet understood) should, in principle, allow fisheries managers to 

forecast likely trends in salmon production some years in the future and make preparations for 

adjusting annual harvest quotas accordingly. The coincident warm ENSO and/or PDO years 

could be anticipated and stocks could be conserved at those times. Extreme caution in harvest of 

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Columbia River species and stocks is advisable when ENSO and PDO cycles are concurrently in 

the warm phase. Conversely, concurrent cool phases could allow a higher managed harvest from

an abundance of most salmon. Practically, however, ENSO is irregular, but the warm peak is still 

reasonably predictable 1-2 years in advance. The PDO cycle is less well known, but caution in 

harvest could be exercised when regime shifts have occurred or seem imminent to a warmer 

portion of the cycle at the end of about 20 years. Perhaps the greatest risk to salmon could come

when harvest managers become accustomed to high harvest levels during favorable periods and 

then fail to recognize climatic change when it occurs and harvest levels are not reduced 

appropriately. Although the desired predictive capabilities are not yet available, the ISAB 

believes harvest managers should be looking to the future to develop such capabilities. 

The harvest-setting process will need to adapt to current understanding of climate changes and 

the rapid pace of new knowledge. The present annual development of pre-season abundance 

forecasts and in-season estimates of returning run sizes can, and probably should, shift to a 

longer temporal focus. Salmon harvest managers may need to become firmly attached to 

climatologists when they plan for both current-year and future harvest quotas. Although a stock 

assessment process is established for determining allowable harvest, these annual assessments 

will need to look farther ahead to incorporate expected ENSO and PDO cycles and to estimate 

whether the stock status in future harvest years will be affected by warm or cool periods, 

especially should they coincide. 

Clearly, climate effects on salmon, whether cycles or long-term trends, have implications greater 

than for just harvest regulations. They affect how critical are the needs for maximizing survival 

of ESA-listed populations, protecting and enhancing important habitats, and managing other 

factors in the salmon life cycles. Overall protection needs to be more assiduous when the cycles 

are in a bad phase for salmon and might be relaxed somewhat when the cycles are in a good 

phase. One should not forget, however, that it is during the better climatic phases that stocks 

below sustainable levels in the poor phase should be allowed to recover their numbers and 

recolonize or expand areas of freshwater production. The reality of climate change cycles and 

trends belies many of the goals of the fishing industry, such as stable employment, consistent 

sources of fish, and firm markets. The nature of the beast, so to speak, will necessarily be one of 

much year-to-year and decade-to-decade variation. Economists and businessmen, as well as 

biologists, will have to learn to expect and contend with such variability. 

What specifically might be done? The ISAB suggests two avenues for consideration: (1) alter the 

temporal focus of harvest management to multiple (future) years; and (2) inform strategies for 

long-term investment. Both ideas would require effort for their substantive development. 

Temporal focus of harvest management. There are both near-term and long-term approaches. For 

the near term and for species that mature at multiple ages, harvest management practices could 

be modified to consider impacts on fish that are not anticipated to return to the Columbia in the 

coming/current year. Several years ago, Morishima (1999) developed a metric termed Mature 

Run Equivalents (MREs) to convert harvest (or environmental) impacts on fish to their 

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ISAB 2005-4 Harvest Report 

equivalents on a return year basis (the idea was employed in the PATH analysis).20 If the MRE 

concept were to be employed in harvest management, the focus of regulation would be changed 

because impacts would be considered on a cumulative basis. Harvest management plans in a 

single year would look at: (a) how factors (fisheries, environmental) that have already occurred 

in previous years have affected the fish that are anticipated to return in the current year; and (b) 

how factors in previous and the current year would be expected to affect prospects for returns in 

future years for the broods that already have begun their contribution to spawners. An MRE-type 

approach would necessitate a considerable change in the focus of harvest management from a 

single return year to multiple years; this would likely involve additional uncertainty that might be 

addressed through application of precautionary management techniques. Because of its near-term

focus, such an approach would not address survival changes beyond the 2-7-year ENSO cycles. 

The long-term approaches are less clear, but would involve anticipation of the ENSO and PDO 

cycles and long-term climate-change trends and their likely impacts on fisheries. As 

environmental predictability improves, the predictive capability for the output of freshwater 

production and the productivity of the ocean environment should improve. Times of lean and 

rich production should be forecasted with sufficient resolution that the likely results for the nearterm would be evident. The near-term analysts would then be forewarned of impending change 

in their analytical ground rules. 

Long-Term Strategy. Long-term climate changes would very likely alter the structure of salmon 

populations, as well as their abundance. The current focus of the ESA on preservation of the 

“status quo” ESUs is not well suited as a foundation for long-term strategic management. Costs 

of attempting to preserve something that cannot be sustained over the long run could be 

enormous, and extraordinary efforts could prove futile in the end. While not limited to harvest 

management issues, an initiative to examine the implications of long-term climate change should 

be valuable from a strategic perspective. It should be feasible to undertake a simulation study 

that would investigate how the 4-Hs might be expected to influence salmon population and 

community structures under various climate change scenarios, in order to inform decision 

makers on alternative futures. For instance, such an approach might integrate models on 

precipitation, flows, EDT, hatchery production, supplementation, habitat modification, etc. to 

determine the likely response of different population units. As information on the implications of 

climate change becomes available, such a model could prove helpful in establishing priorities 

and long-range plans for: 

1. identification and preservation of important populations that could be pivotal to future 

survival of the species; 

2. identification of populations that are unlikely to be preserved regardless of management 

intervention; 

3. infrastructure such as hatchery facilities, gene banks, and supplementation programs; and 

4. investments by the fishing industry. 

The first two areas would obviously be most relevant for harvest management considerations. 

 

20 The idea of MREs differs significantly from the concept of Adult Equivalents which converts impacts in the 

current year to fish that would be expected to return to terminal areas in the current or a future year in the absence of 

fishing.

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ISAB 2005-4 Harvest Report 

In summary, the ISAB anticipates major increases in the understanding of climate change and 

climate cycles in relation to salmon and other natural resources in the next few years, and 

significant increases in the uncertainty of production forecasts in the short to medium term. 

Harvest managers and the harvest industry need to be in close touch with this increased 

understanding and to be prepared to change their procedures accordingly for conducting nearterm and long-term assessments, setting annual quotas, and harvesting fish. 

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63 

7e. A Primer for Salmon Harvest Management 

The relationship between parent spawning abundance (Stock) and subsequent production of 

progeny (Recruitment) is referred to as Stock-Recruitment (S-R) and frequently forms the 

foundation for harvest management. S-R analysis employs mathematical models to estimate the 

production of mature adults from a given level of adult spawning escapement.21 Thus, the 

fundamental data necessary are numbers of spawning adults (by sex and age) and the resulting 

progeny produced. For salmon, we can measure the spawning Stock, but not Recruitment. 

Recruitment refers to vulnerability of fish in a particular fishery and depends both on regulations 

(such as size limits and season structure), and the migration patterns, survival, and growth of the 

progeny. Data sets that are sufficient for S-R analysis are actually rare, but these models still 

form the foundation for harvest management. The relationships are determined for independent 

demographic groups of salmon that can be identified for fishery management (i.e., a stock). 

Two Common Types of S-R Models 

Two types of S-R relationships are most commonly applied in salmon management. 

Fig 7e-1a. Ricker Model Fig 7e-1b. Beverton-Holt Model

Ricker Model. In the Ricker Model (1954), the 

relationship between spawning escapement and 

production is dome-shaped. This model indicates 

that the productivity of the stock is highest at 

low spawner densities and decreases 

monotonically as escapements increase. At high 

spawning escapement levels, strong density 

dependence becomes apparent and production 

actually decreases, as reflected by descending 

right hand limb. 

Beverton-Holt Model. The Beverton-Holt model 

(1957) is hyperbolic in shape and asymptotic in 

form. Density dependence is incremental, 

suggesting that production is limited by some 

environmental carrying capacity. As with the 

Ricker Model, productivity is greatest at low 

spawner densities and decreases monotonically 

with increasing escapements. 

Fundamental Concepts 

 

21 Habitat is also a critical factor in determining productivity of a salmon population but is not addressed in this 

primer. Habitat is the physical template for production (both its productivity and capacity). S/R models assume a 

fixed habitat background and random environmental variation. If temporal trends exist, current parameter estimates 

may be poorly predicted or biased relative to the full set of historical data. 

Ricker Stock-Production Model

Spawners

Production

Replacement

Beverton-Holt Model

Spawners

Production

Replacement
ISAB 2005-4 Harvest Report 

Fundamental Concepts 

Productivity and Capacity

Both the Ricker and Beverton-Holt models are characterized by parameters that relate to 

productivity and capacity. 

The productivity of a stock is its efficiency to produce progeny at very low levels of spawning 

escapement. Each stock is believed to have its own inherent productivity. Graphically, the slope 

of the models at low spawning escapement levels reflects the productivity; the steeper the slope, 

the higher the productivity. It is important to understand that stock productivity is not constant; 

production from a given level of spawning escapement can vary by orders of magnitude 

depending upon freshwater and marine conditions. There is some evidence of cyclic variations in 

marine survival rates (decadal oscillation, see Section 7.d, Climate Change Effects on Potential 

Salmon Harvest); failure to adjust harvest to compensate to prolonged periods of abnormally low 

survival rates can lead to trends in declining spawning escapements and raise concerns for 

resource conservation. The simplistic forms of these S-R models consider each population as an 

independent unit; within complex ecosystems, potential interactions exist between populations, 

species, and harvest. 

The capacity of a stock is the maximum number of fish that the population can be expected to 

produce under average conditions. For the Ricker Model, the capacity is depicted as the peak of 

the dome-shaped production curve. For the Beverton-Holt Model, production approaches an 

asymptotic limit (capacity) as spawning escapement increases. 

Density dependence

Both the Ricker and Beverton-Holt models are based on the concept of density dependent 

productivity, that is, as spawning escapement increases, productivity (the number of adults 

produced per spawner) decreases. The stock becomes more productive, that is, more adults per 

spawner are produced as spawning escapement decreases. This raises the question, “How low 

can you go?” Although S-R theory suggests that the population can be sustained at very low 

levels of spawning escapements, harvest managers avoid risks of extinction or to the long-term

viability of the population by establishing minimum acceptable escapement levels. At very low 

escapement levels, concerns that the population will not be capable of sustaining itself due to 

social dysfunction, failure to mate successfully, mechanical feedback (effects of salmon in 

processing spawning gravel), biogeochemical effects (marine derived nutrients), and genetic 

effects (inbreeding and loss of genetic diversity) – originally described as the “Allee effect” 

(Allee, 1931) but more generally described as “depensation”– outweigh short-term benefits of 

harvest. 

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Sustained Yield

The replacement line depicted on the figures for both the Ricker and Beverton-Holt models 

represents a 1:1 relationship between spawning escapement and production. An unfished 

population would generally be expected to stabilize at the equilibrium point where the 

replacement and production lines intersect. At spawning escapement levels beyond the 

intersection, production would not be expected to replace spawning escapements. To harvest 

managers, the area of greatest interest lies to the left of this intersection. Here, the difference 

between the replacement line and the production model line represents the level of “harvestable 

surplus”, i.e., the number of fish that can be harvested at a given level of spawning escapement 

without depleting the parent stock. 

Maximum Sustained Yield

One common management objective is to maintain spawning escapement at the level that 

maximizes the sustainable yield from the stock, i.e., to achieve the largest difference between 

production and spawning escapement. The size of the harvestable surplus at this point is 

commonly referred to as the Maximum Sustained Yield (MSY) and the associated spawning 

escapement is referred as SMSY. Note that this point typically lies well below the levels of 

maximum production (MSP) and maximum sustainable spawning escapements (Figure 7e-2). 

Stock-Production Relationships

Spawning Stock

Production

SMSY

Conservation (Allee Effect)

Fig. 7e-2. Key characteristics of S-R Models 

In S-R models, each stock has a unique SMSY, but it is important to understand that spawning 

escapements can deviate substantially from this level with minor reductions in sustainable yield. 

For example, suppose that a population characterized by a Beverton-Holt model has an SMSY = 

6,000 and an MSY = 6,000. Spawning escapements ranging from 4,200 to 7,700 would be 

expected to generate sustained yields within 5% of MSY (Figure 7e-3). 

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ISAB 2005-4 Harvest Report 

Sustainable Yield For a Beverton-Holt Model

Spawning Escapement

Sustainable Yield

Escapement Range Capable of Sustaining Yield 

within 5% of MSY

Fig. 7e-3. Sustainable yield for a Beverton-Holt Model

In a nutshell, the Ricker and Beverton-Holt S-R models illustrate that: 

1. increasing salmon escapements will not always increase the potential number of fish 

available for harvest; 

2. the largest sustainable harvest is not normally achieved when the total population size is 

largest; 

3. the maximum sustainable exploitation rate for a population does not yield the maximum 

sustainable yield; and 

4. salmon populations are capable of sustaining themselves and sustaining harvests over a 

broad range of spawning escapements. 

Spawning Escapement Goals

Fisheries management objectives are commonly expressed in terms of spawning escapement 

goals. Implicit in a spawning escapement goal is the desire to perpetuate the resource and 

preserve it for future use. An escapement goal established solely for conservation purposes 

represents the minimum reproductive population that is necessary to assure that the resource can 

be perpetuated. Any escapement goal higher than that necessary for conservation is selected so 

as to utilize the reproductive capacity of the resource in a manner that society determines to be 

“optimal.” The utilization aspect of a spawning escapement goal must be subservient to the 

constraints on exploitation, which are dictated by the conservation necessity. Thus, while there 

may be only a single spawning escapement level associated with conservation of a particular run 

of fish, there are an infinite number of possible spawning escapement levels that can be selected 

to meet various utilization objectives in some "optimal” way. 

The selection of a particular level of harvest and spawning escapement is a social policy decision 

that essentially involves a choice of time preference, i.e., present utilization versus future 

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ISAB 2005-4 Harvest Report 

production potential. A spawning escapement goal may be chosen to meet an endless number of 

legitimate management purposes, such as to: 

• maximize the sustainable harvest; 

• maximize the number of adults produced by the population; 

• enhance scientific knowledge concerning the resource; 

• increase genetic diversity in the population; 

• maximize the value of the total production of all species of fish produced by a watershed; 

• satisfy some aesthetic preference or political desire to see more fish in a river; 

• promote the economic efficiency of a fishery; 

• provide for a level of harvest that can sustain fishing communities; 

• increase the number of spawner carcasses to improve nutrients available to support; 

ecological functions and provide food supplies for progeny; 

• reduce social and economic dislocations; 

• increase or decrease potentials for sustainable harvest. 

A spawning escapement goal established for each of these purposes is “optimal” in its own way. 

Harvest Management 

Harvest management involves the simple concept of constraining the fishery to the level 

necessary to attain a specified management objective, i.e., the primary objective of harvest 

management is to ensure that the cumulative effect of all fisheries does not exceed the impact 

allowable for a given stock. 

As straightforward as this task may sound, the capacity to regulate harvests to attain a given 

management objective can be an extraordinarily difficult and challenging task for many 

Columbia River salmon stocks. The reasons for this difficulty stem from several sources, 

including the biological characteristics of the stock and complex patterns of harvest under the 

jurisdictions of multiple management agencies. 

Biological characteristics of the stock affect the complexity of harvest management. 

Management of coho salmon is relatively simple compared to Chinook. Columbia River coho are 

exploited and spawn predominantly as three-year old fish and ocean distribution patterns are 

limited to the extreme southern portion of British Columbia to northern California. In contrast, 

Columbia River Chinook are exploited at various ages over an extensive migratory range (e.g., 

Snake River fall Chinook are harvested by commercial and recreational ocean fisheries from

central California to Southeast Alaska as well as fisheries in the Columbia River). Further, 

spawning escapements of this species are comprised of fish of different ages. Consequently, 

harvests of Chinook must be constrained over multiple years by multiple jurisdictions (see 

section on Institutional Structure). 

Many different strategies can be employed in salmon harvest management. Two of the most 

basic are described here, harvest management based on: (a) escapement goals, and (b) 

exploitation rates. 

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ISAB 2005-4 Harvest Report 

Escapement Goal Management 

A fixed escapement goal harvest management strategy attempts to attain a level of spawning 

escapement regardless of abundance. If abundance falls below the number required to achieve 

the goal, fisheries impacting the stock are closed. Otherwise, harvest is constrained to take the 

difference between total abundance and the escapement goal. 

To attain an escapement goal, all fisheries impacting a given stock must be appropriately 

regulated so as to ensure that the appropriate harvest is not exceeded. This can be an 

extraordinarily difficult and challenging task for many Columbia River salmon stocks because of

the complex life histories and number of jurisdictions involved. Escapement goal management 

thus requires a high degree of cooperation and coordination between jurisdictions affecting 

individual stocks, as well as information-intensive management systems. 

While escapement goal policies place a premium on future production, they can have undesirable 

social consequences. Since salmon survivals often exhibit very high interannual variability, fixed 

escapement goal policies can lead to “boom or bust” instability and economic dislocation of 

fisheries. Fixed escapement policies are not always feasible or even desirable, given a stock’s 

pattern of exploitation. For instance, a stock may be harvested only by highly mixed stock 

fisheries outside the jurisdiction of the harvest manager; or there may be little capability to 

estimate abundance and adjust harvest to achieve an established escapement goal; or a stock may 

be taken incidentally during fisheries targeted at other abundant, valuable species with 

harvestable fish. 

In practical terms, harvest management is an imprecise process. Fortunately, salmon populations 

are proven to be quite robust, capable of enduring wide variability in freshwater and marine 

survivals as well as harvest management error over an extended period of time. As indicated in 

Figure 4, the failure to exactly achieve a given spawning escapement goal in a single year should 

not raise alarms about a conservation crisis. 

Exploitation Rate Management 

Within the range of sustainable harvests, the sustainable exploitation rate is determined by the 

productivity of the stock, but must of course assume a value above zero (in the absence of an 

Allee effect) and less than one. An important characteristic of S-R models is that there is a 

unique sustainable exploitation rate associated with each given level of spawning escapement. 

Two reference points of particular interest to harvest managers are depicted in Figure 7e-4. 

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ISAB 2005-4 Harvest Report 

Sustainable Exploitation Rate

For A Beverton-Holt Model

Spawning Escapement

Sustainable Exploitation 

Rate

Conservation Concern 

MSY

Fig 7e-4. Sustainable exploitation rate fo MSY (circle) and conservation concern 

spawning escapement level (square) for a Beverton-Holt Model. 

r

The circle represents the sustainable exploitation rate at MSY, while the square represents the 

sustainable exploitation rate at the level of spawning escapement associated with potential 

conservation concerns because of the potential for an Allee effect. 

Under an exploitation rate strategy, the objective is to constrain exploitation rates so that a 

desired level of spawning escapement (e.g., SMSY) can be attained over time. Because of data 

limitations, it is often easier to generate an estimate of the exploitation rate associated with SMSY

than it is to estimate SMSY itself. 

The theory behind the exploitation rate strategy is that, if fishery exploitation rates are 

constrained to the level appropriate for SMSY, escapements should eventually stabilize at SMSY

over time, if the environment is constant. 

When spawning escapement is below SMSY, the population can sustain a higher exploitation rate. 

Consequently, when fisheries are managed to achieve the lower sustainable exploitation rate 

associated with SMSY, fewer fish would be harvested and spawning escapements would be 

expected to increase. For example, suppose that a population that produces fish according to a 

Beverton-Holt model can sustain a 50% exploitation rate at an SMSY = 6,000. Suppose further 

that a spawning escapement for that population produces 9,000 fish at an escapement of 3,600 

fish. The sustainable harvest at that level is 9,000-3,600 = 5,400, so an exploitation rate of 60% 

(= 5,400/9,000) can be sustained. If fishery exploitation rates are constrained to 50%, 4,500 fish 

would be harvested and 4,500 fish would escape; the spawning escapement for the next 

generation would consequently increase from 3,600 to 4,500. 

Conversely, when spawning escapement is above SMSY, the population can sustain a lower 

exploitation rate. When fisheries are managed to achieve the higher sustainable exploitation rate 

associated with SMSY, the harvest would exceed the sustainable level so spawning escapements 

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ISAB 2005-4 Harvest Report 

would be expected to decrease. For example, if a spawning escapement level of 8,400 fish 

produces 14,000 fish, the sustainable yield would be 5,600 fish and the associated sustainable 

exploitation rate would be 40% (= 5,600/14,000). By allowing a 50% exploitation rate associated 

with SMSY, the catch would be 7,000 fish and the spawning escapement for the next generation 

would be reduced from 8,400 to 7,000 fish. 

Exploitation rate strategies are less dependent upon estimates of abundance than are escapement 

goal strategies, and the approach can be implemented at lower cost and with reduced potential 

for fishery disruptions. However, as with fixed spawning escapement goal harvest management 

strategies, a fixed exploitation rate strategy, blindly followed, can also have undesirable 

consequences. If spawning escapement levels fall below critical levels or sustained periods of 

abnormally low productivity are experienced, a fixed exploitation rate strategy can lead to stock 

collapse. 

Neither fixed spawning escapement goal nor fixed exploitation rate management performs well 

in a dynamic environment with high inter-annual variability in survival rates, growth, habitat 

conditions, and patterns of fishery exploitation. Today, dogmatic adherence to such inflexible 

strategies has fallen into disfavor. Harvest managers are increasingly turning to a combination of 

the two, a ceiling on allowable exploitation rates adjusted for current expectations for short-term

marine survivals, coupled with a spawning escapement floor to protect against stock collapse. 

Management of Mixed Stock Fisheries 

To this point, the discussion of harvest management strategies has been limited to circumstances 

where fisheries exploit a single population. However, nearly all fisheries on Columbia River 

stocks impact multiple stocks. Figure 7e-5 illustrates how stocks with different productivities are 

impacted in mixed stock fisheries. Sustainable exploitation rates for three populations with 

different productivities (Beverton-Holt Model) are depicted, each with points associated with 

MSY (circles) and conservation concerns (squares). The lowest line represents the least 

productive population while the uppermost line represents the most productive population. Note 

that different productivities alter both the sustainable exploitation rate and the range of spawning 

escapements that are capable of sustaining harvests (the least productive stock has the shortest 

range of sustainable escapement levels). 

If a stock mixture is exploited at the MSY rate appropriate for the most productive stock (about 

65% in this example), then the least productive stock would be extirpated over time because it 

cannot sustain exploitation rates in excess of about 40%. Spawning escapement for the third 

(middle) population would be expected to stabilize at a level well below its SMSY, but the longterm viability of this stock would not be threatened. 

To conserve the least productive stock, the exploitation rate in mixed-stock fisheries must be 

decreased to about 40%. Additional fisheries, though, could be conducted once the more 

productive stocks become separated from the less productive ones. 

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Sustainable Exploitation Rates For

Beverton-Holt Models With Different Productivities

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Spawning Escapement

Sustainable Exploitation 

Rate

Prod = 0.5 Prod = 1.0 Prod = 2.0

Fig 7e-5. Sustainable exploitation rate fo MSY (circle) and conservation concern 

spawning escapement level (square) for Beverton-Holt Models with different 

productivities.

r

How do harvest managers attempt to contend with complex mixtures of stocks of different sizes 

and with different productivities and patterns of exploitation? The short answer is that, until 

recently, they haven’t. Historically, harvest management failed to pay adequate attention to 

smaller stocks and differing capacities of individual populations to sustain harvest. The most 

notorious example is with hatchery-wild stock mixtures. In the Columbia River system, 

numerous hatcheries were constructed to produce fish to mitigate for habitat loss and degradation 

due to the construction of dams. These hatcheries released prodigious numbers of fish which 

were exploited at the highest rates possible while meeting egg take needs. Commingled naturally 

spawning stocks with lower productivities were unable to sustain the exploitation rates being 

exerted on the hatchery fish. Over time, naturally spawning coho populations were virtually 

extirpated from the Columbia River (save for very small remnant populations that are now 

candidate species being considered for listing under the Endangered Species Act) and became so 

depressed on Oregon coastal streams that they were listed as threatened under the Endangered 

Species Act. 

How do harvest managers of mixed stock fisheries today attempt to simultaneously achieve 

specific objectives for each population in order to meet concerns for biodiversity and long-term

viability? Managers of highly mixed stock fisheries have found it infeasible to try to attain fixed 

spawning escapement goals for every stock all the time. The approach now being embraced is to 

rely upon exploitation rate management. With mixtures of stocks with different productivities, 

the exploitation rates must be constrained so as not to exceed the level associated with critical 

conservation points on the stock (component) with the lowest productivity over extended periods 

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ISAB 2005-4 Harvest Report 

of time. Production from each of the populations will not be sustained at SMSY levels, but 

viability should not be compromised. 

Current management of Columbia River coho in mixed stock ocean fisheries, for example, is 

driven by exploitation rates that are determined by the annual status of Oregon coastal natural 

coho under the Pacific Fishery Management Council’s Salmon Framework Plan (OCN 2000). 

The allowable exploitation rate under that Plan ranges from zero to a high of 45%, substantially 

below annual exploitation rates on hatchery fish that had approached 80% prior to the 1990s. In 

addition to reductions in mixed stock exploitation rates, the stock assessment program was 

improved to provide data to monitor stock response and trigger adjustments to management 

strategies if stocks responses fail to meet expectations. 

Information Requirements 

Harvest management strategies require extensive information for implementation. 

For S-R analysis, data are required to characterize the relationship between spawning 

escapement and productivity and to estimate model parameters. The first step is to identify the 

reproducing population. This involves information on the dynamics of the metapopulations 

(populations that regularly interbreed) that may be involved. Once the reproducing population is 

identified, data on spawning escapements and production are required. 

Spawning escapement data. For salmon, the number of adult spawners is commonly used in S-R 

analysis because adults are presumed to contribute most to future production. While S-R analysis 

can be performed using estimates of total spawning escapements, results can be clouded because 

the reproductive potential of that escapement is influenced by its age-sex composition. For 

example, the reproductive potential of a spawning stock of Chinook, which is comprised 

primarily of three-year old males, is vastly different from an escapement dominated by larger, 

older females. Ideally, data on the characteristics of the spawning population, such as age, sex, 

size, and fecundity would be available along with estimates of error. 

For S-R analysis based on fish-to-fish relationships, spawning escapement data are often 

available over a very limited range. Observations at low escapements are necessary to estimate 

the inherent productivity of the stock. Observations at relatively high escapement levels are 

needed to provide the information required to define the response to changes in spawning stock 

size. Data limitations commonly prove problematic when attempting to employ S-R analysis. 

Usually, S-R analyses only involve a small number of observations and little quantitative 

information about uncertainty (principally measurement error) surrounding these estimates is 

available. Further, the data are often inconsistent over time, reflecting changes in methods, 

personnel, and variations in environmental conditions. 22 

 

22 A variety of methods can be employed to apply S-R theory to harvest management in the face of uncertainty. For 

example, an adaptive management approach can be instituted to obtain information on production response by

monitoring juvenile production when spawning escapements are intentionally varied. Another approach could 

involve the estimation of habitat carrying capacity, coupled with estimates of productivity at low spawner densities. 

Production can also be estimated by dividing the sum of spawning escapements and terminal harvests for a given 

brood year by the adult-equivalent-brood year exploitation rates estimated from cohort analysis of representative 

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Estimating Production. For estimation of spawning escapements, measurement error is of 

principal concern. When it comes to production, both measurement error and process error 

(variable production from a given level of spawning escapement) must be taken into account. 

For either the Ricker or Beverton-Holt models, production from a given spawning escapement is 

usually expressed in terms of adult equivalents23 because fish can be exploited at different stages 

of maturity. For Chinook, data on escapements, catch, and tagging experiments form the most 

common foundation for estimating production. 

Ideally, production estimates would begin by estimating egg-deposition resulting from a given 

spawning escapement. Then spawning escapement surveys from subsequent years provide 

estimates of the number of fish produced by this escapement, which survive to spawn by age. 

Since Chinook mature at different ages, data may be collected over 3-6 years to estimate the 

production from a single spawning escapement. Since escapement in any given year is comprised 

of fish produced by several different broods, the number of spawners must be partitioned into 

fish of different age classes in order to estimate production from individual broods. A variety of 

methods are used (e.g., age structure of catch in terminal fisheries) that can introduce bias if 

sampling techniques (e.g., size or sex selectivity of gear) are not random. Partitioning should 

involve all age classes. 

Estimates of production would finally be generated by expanding spawning escapements for prespawning mortality, fishing mortality, and natural mortality based on tagging data. For most 

natural stocks, estimates of pre-terminal fishery exploitation are derived from CWT experiments 

involving a closely related hatchery stock. Cohort analysis of CWT data is commonly employed 

to provide estimates of impacts of pre-terminal fisheries, natural mortality, maturation schedules, 

and adult equivalence factors. The basic procedure for estimating production in adult equivalents 

involves the following steps: 

For each age class:

1. Estimate Spawning Escapement. 

2. Estimate escapement past fisheries by dividing (1) by an estimate of pre-spawning, 

post-fishery survival. 

3. Estimate the terminal run size by adding terminal fishery impacts to (2). 

 CWT data. Care must be taken, however, to account for potential differential estimation of spawning escapement by 

age and sex. For some early-maturing stocks, the failure to account for precocious males could bias estimates of 

production. This is because accurate spawning escapement estimates for jacks are rarely available, but jacks are 

included within estimates of adult equivalent brood year exploitation rates. When it is not possible to generate useful

estimates of age-specific spawning escapements, other procedures can be employed. For instance, assumptions may 

be made regarding the predominant age class in escapement so that spawning escapement and production can be

lagged by a fixed interval. 

23 Adult equivalents are the number of potential adults that would be expected to return to their rivers of origin in the 

absence of fishing. Morishima (1999) provides detailed information regarding the derivation and use of various 

metrics employed in fishery management. 

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ISAB 2005-4 Harvest Report 

4. Estimate the number of fish remaining in the ocean after fishing by dividing the 

terminal run (3) by the maturation rate derived from cohort analysis. 

5. Estimate the cohort size prior to fishing by dividing (4) by (1- ocean fishery 

exploitation rate) derived from cohort analysis. 

6. Estimate the ocean fishing mortality by multiplying (5) by the ocean fishery 

exploitation rate derived from cohort analysis. 

7. Estimate ocean fishing mortality in adult equivalents by multiplying (6) by the adult 

equivalence factor derived from cohort analysis. 

8. Normalize adult equivalent ocean fishing mortality to compensate for variability in 

early marine survivals. When performing stock-production analysis, the environment 

in which these fish reproduce is assumed to be stable. This assumption is of 

questionable validity, given the time required to obtain each observation (e.g., 5-6 

years for Chinook) and high variability in marine survival rates. Normalization also 

provides a means to try to distinguish between variations due to process error and 

trends or survival patterns associated with periodic environmental conditions. 

To estimate production from the brood year escapement, ocean fishing mortality in adult 

equivalents and terminal run sizes by age are summed. In summary, the capacity to employ S-R 

analysis to guide harvest management requires well-designed monitoring programs for 

estimating spawning escapement and impacts of pre-terminal fishing. The estimates for S-R 

analysis for many of the ESA listed stocks are subject to very large error because the counts may 

be contaminated by inclusion of supplementation releases or hatchery strays, and because the 

estimate of central importance is the effective number of recruits per spawner of natural 

spawning origin. This latter requires distinguishing between the naturally spawned progeny of 

supplementation releases (or strays) and the naturally spawned progeny of fish that themselves 

were naturally spawned. Empirical measurements of these respective rates are generally lacking, 

and “expert opinion” spans a wide range. 

 

Abundance Estimates. Annual implementation of harvest management strategies involves 

information about abundance, both preseason and in-season. The same types of data required for 

S-R analysis have proven to be useful for preseason abundance forecasting. For many stocks, 

estimates of age-specific spawning escapements, terminal run sizes, and ocean exploitation rates 

provide the basis for annual abundance forecasts that drive harvest management planning 

processes. These forecasts commonly rely upon sibling relationships; the abundance of a 

younger age class from a given brood year has proven to be a useful indicator of the abundance 

of older age classes. 

Reliable in-season estimates of abundance for individual populations of interest to harvest 

management are rarely available for highly mixed-stock fisheries. In-season estimates of 

abundance are extensively employed in the management of terminal area fisheries in order to 

constrain fishing mortality to achieve specific management objectives for escapements. Methods 

74 
ISAB 2005-4 Harvest Report 

used to estimate abundance as fish approach terminal areas involve consideration of a variety of 

data, including dam or weir counts, run timing patterns, catch rates, and tag detections. 

Fishery monitoring. Harvest management requires estimates of fishing mortalities to constrain 

impacts to allowable levels. For highly mixed-stock fisheries, the composition of fishery 

mortalities is projected through the use of planning models that integrate annual, stock-specific 

forecasts of abundance, historical CWT data to characterize observed patterns of fishery 

exploitation on individual stocks, and expectations for fishing patterns. Data collected to monitor 

ocean fisheries are largely limited to aggregate catches of all stocks and ages, fishing effort and 

catch rates, and fish size. Catches are monitored in-season to ensure that allowable harvest levels 

(e.g., quotas) are not exceeded. Effort and catch rates are employed to determine opening and 

closing dates for fisheries and to identify substantial deviations from preseason expectations of 

abundance and fishing patterns. Data on fish size are commonly relied upon to detect abnormal 

ocean conditions that affect growth and survival. In terminal areas, fishing effort patterns and 

stock-specific estimates of fishery impacts are considered when decisions are made to open or 

close fisheries in-season. Monitoring fishing mortality rates for ESA listed stocks presents 

special and severe practical difficulties. These stocks for the most part are not tagged or marked, 

and estimates of their fishing mortality depends on extrapolation from estimates of fishing 

mortality rates on other marked stocks which are predominantly hatchery stocks. The uncertainty 

introduced by this extrapolation needs some attention for it to be quantified realistically. Further, 

listed stocks are rare in abundance and difficult to sample in large mixtures of stocks in most 

fisheries. 

Variable needs for accuracy and precision. Figure 7e-5 depicts the need to consider different 

productivities in the management of mixed stock fisheries. This figure also illustrates the effect 

of prolonged periods of abnormal survival. The middle line representing an average stock could 

just as well represent the exploitation rate that can be sustained by a single population under 

normal environmental conditions. The upper and lower lines could then represent the 

exploitation rates that can be sustained when survivals are abnormally high and low, 

respectively. These lines indicate that different exploitation rates for the same population would 

be appropriate if prolonged periods of abnormal survivals are experienced; for example, the 

lower line indicates that a failure to reduce exploitation rates during a period of prolonged 

depression in survivals could lead to stock depression or even extirpation over time. 

Figure 7e-5 provides insight into how changes in stock status or differences in productivities 

among populations might be taken into account in monitoring programs. When survival is above 

average (or for more productive populations) and exploitation rates are low relative to 

sustainable levels, a greater degree of imprecision can be tolerated in estimates of exploitation 

rates and spawning escapements. In contrast, the steep slope of the lower line indicates that 

sustainable exploitation rates for less productive populations are much more sensitive to 

spawning escapement levels and that harvests can be sustained over a much narrower range of 

spawning escapements. When survival is low (or for stocks with low productivity), tolerance for 

error decreases. Monitoring programs should be capable of providing more precise and accurate 

estimates of fishery exploitation and spawning escapements for less productive stocks or during 

periods of depressed survivals, especially when exploitation rates are allowed to approach 

conservation limits. 

75 
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8. Literature Cited by Sections 

Executive Summary citation: 

ASFEC (Ad Hoc Selective Fishery Evaluation Committee) 1995. Pacific Salmon Commission 

Selective Fishery Evaluation. June 9, 1995. SFEC. 2002. Investigations of Methods to 

Estimate Mortalities of Unmarked Salmon in Mark-Selective Fisheries through the use of 

Double Index Tag Groups. TCSFEC(02)-1. February, 2002. (www.psc.org/publ/)

Section 2 citations: 

Beamish, R.J., J.T. Schnute, A.J. Cass, C.M. Neville, and R.M. Sweeting. 2004. The influence of 

climate on the stock and recruitment of Pink and Sockeye salmon from the Fraser River, 

British Columbia, Canada. Trans. Am. Fish. Soc. 133: 1396-1412. 

Coronado, C. and R. Hilborn. 1998a. Spatial and temporal factors affecting survival in coho 

salmon (Oncorhynchus kisutch) in the Pacific Northwest. Can. J. Fish. Aquat. Sci. 55: 2067-

2077. 

Coronado, C. and R. Hilborn. 1998b. Spatial and temporal factors affecting survival in coho and 

fall chinook salmon in the Pacific Northwest. Bull. Mar. Sci. 62(2): 409-425. 

Jefferts, K.B., P.K. Bergman, and H.F. Fiscus. 1963. A coded wire identification system for 

micro-organisms. Nature (London) 198: 460-462. 

Johnson, J.K. 1990. Regional Overview of Coded Wire Tagging of Anadromous Salmon and 

Steelhead in Northwest America. American Fisheries Society Symposium 7: 782-816. 

Lawson, P.W., E.A. Logerwell, N.J. Mantua, R.C. Francis, and V.N. Agostini. 2004. 

Environmental factors influencing freshwater survival and smolt production in Pacific 

Northwest coho salmon (Oncorhynchus kisutch). Can. J. Fish. Aquat. Sci. 61: 360-373. 

Morishima, G.S. and K.A. Henry. 2000. The history and status of Chinook and coho salmon 

ocean fisheries and prospects for sustainability. In Sustainable Fisheries Management: 

Pacific Salmon. E.E. Knudsen, C.L. Steward, D.D. MacDonald, J.E. Williams, and D.W.

Reiser (Eds.). Lewis Publ., N.Y. 724p. 

Moulton, F.R. (ed.). 1939. The migration and conservation of salmon. Publication of the 

American Association for the Advancement of Science 8. 

Ratner, S., R. Lande, B.B. Roper. 1997. Population viability analysis of spring Chinook salmon 

in the South Umpqua River, Oregon. Cons. Biol. 11(4): 879- 889. 

Ricker, W.E. 1954. Stock and recruitment. J. Fish. Res. Bd. Canada 11: 559-623. 

76 
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Ricker, W.E. 1958. Maximum sustained yields from fluctuating environments and mixed stocks. 

J. Fish. Res. Bd. Canada 15: 991-1006. 

Ricker, W.E. 1972. Heredity and environmental factors affecting certain salmonid populations. 

p. 19-160. In: R.C. Simon and P.A. Larkin (eds.). The Stock Concept in Pacific Salmon. H.R. 

MacMillan Lecture in Fisheries. UBC, Vancouver, BC. 

Washington Dept. Fish and Wildlife. 2003. Escapement Goals for Upriver Bright (URB) Fall 

Chinook Salmon Stocks of the Columbia River. Contract report NMFS Contract # 

NA97FP0383, WDFW Contract #22600052. WDFW. 600 Capitol Way N., Olympia, Wash. 

98501-1091. 

Section 3 citations: 

PSC. 1999. Treaty between the Government of Canada and the Government of the United States 

of America Concerning Pacific Salmon. Pacific Salmon Commission, 600-1155 Robson 

St., Vancouver, BC V6E 1B5. (http://www.psc.org/pubs/Treaty.pdf) 

Ricker, W.E. 1958. Maximum sustained yields from fluctuating environments and mixed stocks. 

J. Fish. Res. Bd. Canada 15: 991-1006. 

TCCHINOOK(04)-4. 2004. Annual exploitation rate analysis and model calibration. December, 

2004. Pacific Salmon Commission, 600-1155 Robson St., Vancouver, BC V6E 1B5. 

Sections 4 and 5 citations: 

Beverton, R.J.H. and S.J. Holt. 1957. On the Dynamics of Exploited Fish Populations. U.K. Min, 

Agric. Fish., Fish. Invest. (Ser. 2)19:533p. 

Dygert, P. and S. Bishop. 2004. NOAA Fisheries’ Approach to Making Determinations Pursuant 

to the Endangered Species Act about the Effects of Harvest Actions on Listed Pacific 

Salmon and Steelhead. Northwest Region. Sustainable Fisheries Division. Report 

Prepared by Northwest Region, Sustainable Fisheries Division, NOAA Fisheries. 

November 16, 2004. 13 p. w/attachments. 

Federal Caucus. 2000. Conservation of Columbia Basin Fish Final Basinwide Salmon 

Recovery Strategy Volumes 1, 2 and 3. December 21, 2000. 

www.salmonrecovery.gov/Archive_chronological.shtml 

Hilborn, R. and C.J. Walters. 1992. Quantitative Fisheries Stock Assessment: choice, dynamics, 

and uncertainty. Chapman and Hall, New York. 

ISAB (Independent Scientific Advisory Board). 2003. Review of salmon and steelhead 

supplementation. ISAB 2003-3. Northwest Power and Conservation Council, Portland, 

OR. (www.nwcouncil.org/fw/isab/) 

77 
ISAB 2005-4 Harvest Report 

ISAB (Independent Scientific Advisory Board) and ISRP. 2005. Review of the All-H 

Analyzer (AHA). ISRP/AB 2005-5. (www.nwcouncil.org/fw/isab) 

ISAB (Independent Scientific Advisory Board) and ISRP. 2005. Viability of ESUs containing 

multiple types of populations. ISAB/RP 2005-3. (www.nwcouncil.org/fw/isab) 

Kareiva, P., M. Marvier, and M. McClure. 2000. Recovery and management options for 

spring/summer Chinook salmon in the Columbia River Basin. Science 290: 977-979. 

Lee, K.N. 1999. Appraising adaptive management. Cons. Ecology 3(2). Online: 

www.consecol.org/vol3/iss2/art3/

Levine, P.S., and J.G. Williams. 2002. Interspecific effects of artificially propagated fish: an 

additional conservation risk for salmon. Cons. Biol. 16(6): 1-8. 

Levin. P.S., R.W. Zabel, and J.G. Williams. 2001. The road to extinction is paved with good 

intentions: negative associations of fish hatcheries with threatened salmon. Proc. Royal 

Soc. London, Series B 286: 1-6. 

Marmorek, D. and C. Peters. 2001. Finding a PATH toward scientific collaboration: insights 

from the Columbia River Basin. Cons. Ecology 5(2). Online: 

www.consecol.org/vol5/iss2/art8/

McElhany, P., M.H. Ruckelshaus, M.J. Ford, T.C. Wainwright, and E.P. Bjorkstedt. 2000. 

Viable salmonid populations and the recovery of evolutionary significant units. U.S. 

Dept. Commerce, NOAA Tech. Memo. NMFS-NWFSC-42, 156p. 

McElhany, P. (plus 12 authors on the Willamette/Lower Columbia Technical Recovery 

Team). 2003. Interim Report on Viability Criteria for Willamette and Lower Columbia 

Basin Pacific Salmonids. (www.nwfsc.noaa.gov/trt/wlc_viabrpt/complete.pdf) 

NMFS-NWFSC. 2001. RAP A Risk assessment procedure for evaluating harvest mortality on 

Pacific salmonids. Sustainable Fisheries Division, NMFS/NW Region. Sept 2001. 

Restrepo VR, Thompson GG, Mace PM, Gabriel WL, Low LL, MacCall AD, Methot RD, 

Powers JE, Taylor BL, Wade PR, Witzig JF. 1998. Technical guidance on the use of 

precautionary approaches to implementing National Standard 1 of the MagnusonStevens Fishery Conservation and Management Act. NOAA Tech Memo NMFSF/SPO-31. 

Sweeting, R.M., R.J. Beamish, D.J. Noakes, and C.M. Neville. 2003. Replacement of wild coho 

salmon by hatchery-reared coho salmon in the Strait of Georgia over the past three 

decades. N. Amer. J. Fish. Manage. 23: 492-502.

Ricker, W.E. 1954. Stock and recruitment. J. Fish. Res. Bd. Canada 11: 559-623. 

78 
ISAB 2005-4 Harvest Report 

Walters, C. 1986. Adaptive Management of Renewable Resources. Macmillan Publ. 

Walters, C. J. 1995. Fish on the line: the future of Pacific fisheries. Report to the David Suzuki 

Foundation, Fisheries Project, Phase 1, Vancouver, B.C. 82 p. 

Waples, R.S. 2002a. Effective size of fluctuating salmon populations. Genetics 161: 783-791. 

Waples, R.S. 2002b. Evaluating the effect of stage-specific survivorship on the Ne/N ratio. 

Molecular Ecology (2002) 11: 1029-1037. 

Section 6 citations: 

ASFEC (Ad Hoc Selective Fishery Evaluation Committee) 1995. Pacific Salmon Commission 

Selective Fishery Evaluation. June 9, 1995. SFEC. 2002. Investigations of Methods to 

Estimate Mortalities of Unmarked Salmon in Mark-Selective Fisheries through the use of 

Double Index Tag Groups. TCSFEC(02)-1. February, 2002. (www.psc.org/publ/) 

Dygert, P. and S. Bishop. 2004. NOAA Fisheries’ Approach to Making Determinations Pursuant 

to the Endangered Species Act about the Effects of Harvest Actions on Listed Pacific 

Salmon and Steelhead. Northwest Region. Sustainable Fisheries Division. Report 

Prepared by Northwest Region, Sustainable Fisheries Division, NOAA Fisheries. 

November 16, 2004. 13 p. w/attachments. 

Section 7a citations: 

Berg, A., editor. 1981. STOCS: The stock concept symposium. Can. J. Fish. Aquat. Sci. 38(12). 

Brannon, E., M. Powell, T. Quinn, and A. Talbot. 2002. Population structure of Columbia River 

Basin chinook salmon and steelhead trout. Final Report to BPA and NSF. University of 

Idaho, Moscow, ID. 

Columbia Basin Bulletin. 2004. 4. GOOD NEWS, BAD NEWS FOR LOWER COLUMBIA 

RIVER GILLNETTERS. September 24, 2004. 

Cushing, D. 1968. Fisheries biology – a study in population dynamics. University of Wisconsin 

Press, Madison. 

Fraser, D.J. and L. Bernatchez. 2001. Adaptive evolutionary conservation: towards a unified 

concept for defining conservation units. Molecular Ecology 10: 2741-2752. 

Hallerman, E.M., editor. 2003. Population Genetics: Principles and Applications for Fisheries 

Scientists. American Fisheries Society, Bethesda, MD. 

Hilborn, R., T. P. Quinn, D. E. Schindler and D. E. Rogers. 2003. Biocomplexity and fisheries 

sustainability. Proceedings of the National Academy of Science (PNAS) 100:6564-6568. 

Hyatt, K. D. and B. E. Riddell. 2000. The importance of “stock” conservation definitions to the 

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concept of sustainable fisheries. Pages 51 – 62 in E. E. Knudsen, C. R. Steward, D. D. 

MacDonald, J. E. Williams, and D. W. Reiser, editors, Sustainable Fisheries 

Management: Pacific Salmon. CRC Press, Boca Raton. 

Morishima, G. S., and K. A. Henry. 2000. The history and status of Pacific Northwest Chinook 

and coho salmon ocean fisheries and prospects for sustainability. Pages 219 – 236 in E. 

E. Knudsen, C. R. Steward, D. D. MacDonald, J. E. Williams, and D. W. Reiser, editors, 

Sustainable Fisheries Management: Pacific Salmon. CRC Press, Boca Raton. 

Myers, J., C. Busack, D. Rawding, and A. Marshall. 2003. Historical population structure of 

Willamette and Lower Columbia River Basin Pacific salmonids. WLC-TRT Report. 

NOAA Fisheries Northwest Fisheries Science Center. Seattle WA. 

NOAA. 2003. Endangered species act section 7 consultation – supplemental biological opinion. 

Consultation Number: F/NWR/2003/00357. July 11, 2003. 23 p. 

Noss, F.R. 1990. Indications for monitoring biodiversity: a hierarchical approach. Conservation 

Biology 4: 355-364. 

Riddell, B.E. 1993. Spatial organization of Pacific salmon: What to conserve? P. 23-41. In J.G. 

Cloud and G.H. Thorgaard (ed). Genetic Conservation of Salmonid Fishes. Plenum Press, 

NY. 

Ryman, N., and F.M. Utter, editors. 1987. Population genetics and fishery management. 

Washington Sea Grant College Program, Seattle. 

 

TAC (U.S. v. Oregon Technical Advisory Committee). 2003. Steelhead handle and mortality 

impacts in the 2002 non-Indian spring Chinook tangle net fisheries. January 22, 2003. 

Waples, R.S. 1991. Genetic interactions between hatchery and wild salmonids: lessons from the 

Pacific Northwest. Canadian Journal of Fisheries and Aquatic Sciences 48:124-133. 

Waples, R.S. 1995. Evolutionary significant units and the conservation of biological diversity 

under the Endangered Species Act. Pages 8-27 in J.L. Nielson and G.A. Powers, editors, 

Evolution and the Aquatic Ecosystem: Defining Unique Units in Population 

Conservation. 

Section 7b citations: 

Bilby, R. E., B. R. Fransen and P. A. Bisson. 1996. Incorporation of nitrogen and carbon from

spawning coho salmon into the trophic system of small streams: evidence from stable 

isotopes. Canadian Journal of Fisheries and Aquatic Sciences 53: 164-173. 

Bilby, R.E., B.R. Fransen, P.A. Bisson, and J.K. Walter. 1998. Response of juvenile coho salmon 

(Oncorhynchus kisutch) and steelhead (O. mykiss) to the addition of salmon carcasses to 

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two streams in southwestern Washington, U.S.A. Canadian Journal of Fisheries and 

Aquatic Sciences 55:1909-1918. 

Bilby, R.E., B. R. Fransen, J. W. Walter, C. J. Cederholm and W. J. Scarlett. 2001. Preliminary 

evaluation of the use of nitrogen stable isotope ratios to establish escapement levels for 

Pacific salmon. Fisheries 26(1): 6-14. 

Bilby, R. E., E. W. Beach, B. R. Fransen, J. K. Walter and P. A. Bisson. 2003. Transfer of 

nutrients from spawning salmon to riparian vegetation in western Washington. Trans. 

Amer. Fish. Soc.132:733-745. 

Cederholm, C. J., D. B. Houston, D. L. Cole, and W. J. Scarlett. 1989. Fate of coho salmon 

(Oncorhynchus kisutch) carcasses in spawning streams. Canadian Journal of Fisheries and 

Aquatic Sciences 46: 1347-1355. 

Eastman, D. E. 1997. Response of freshwater fish communities to spawning sockeye salmon 

(Oncorhynchus nerka). M. S. Thesis. University of Washington, Seattle. 

Finney, B.P. 1998. Long-term variability in Alaskan sockeye salmon abundance determined by 

analysis of sediment cores. North Pacific Anadromous Fish Commission Bulletin 1:388-

395. 

Finney, B.P., I. Gregory-Eaves, J. Sweetman, M.S.V. Douglas, and J.P. Smol. 2000. Impacts of 

climatic change and fishing on Pacific salmon abundance over the past 300 years. Science 

290:795-799. 

Gross, H.P., W.A. Wurtsbaugh, and C. Luecke. 1998. The role of anadromous sockeye salmon 

(Oncorhynchus nerka) in the nutrient loading and productivity of the Sawtooth Valley 

Lakes, Idaho. Transactions of the American Fisheries Society. 127:1-18. 

Haig-Brown, R. 1946. A river never sleeps. Crown Publishers, NY, NY. 

Helfield, J.M., and R.J. Naiman. 2001. Effects of salmon-derived nitrogen on riparian forest 

growth and implications for stream habitat. Ecology 82:2403-2409. 

Hyatt, K. D. and J. G. Stockner. 1985. Responses of sockeye salmon (Oncorhynchus nerka) to 

fertilization of British Columbia coastal lakes. Canadian Journal of Fisheries and Aquatic 

Sciences 42: 320-331. 

Johnston, N. T., C. J. Perrin, P. A. Slaney, and B. R. Ward. 1990. Increased juvenile salmonid 

growth by whole river fertilization. Canadian Journal of Fisheries and Aquatic Sciences 47: 

862-872. 

Johnston, N. T., MacDonald, J. S., Hall, K. J., and Tschaplinski, P. J. 1997. A preliminary study 

of the role of sockeye salmon (Oncorhynchus nerka) carcasses as carbon and nitrogen 

sources for benthic insects and fishes in the “Early Stuart” stock spawning streams, 1050 

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km from the Ocean. British Columbia Ministry of Environment, Lands and Parks, Fisheries 

Project Report RD55. Victoria, British Columbia. 

 

Juday, C., W. H. Rich, G. I. Kemmerer, and A. Mean. 1932. Limnological studies of Karluk 

Lake, Alaska 1926-1930. Bulletin of the U. S. Bureau of Fisheries 47: 407-436. 

Kline, T. C., Jr., J. J. Goering, O. A. Mathisen, P. H. Poe, and P. L. Parker. 1990. Recycling of 

elements transported upstream by runs of Pacific salmon: I. δ15N and δ13C evidence in 

Sashin Creek, southeastern Alaska. Canadian Journal of Fisheries and Aquatic Sciences 47: 

136-144. 

Kline, T. C., Jr., J. J. Goering, O. A. Mathisen, P. H. Poe, P. L. Parker, and R. S. Scalan. 1993. 

Recycling of elements transported upstream by runs of Pacific salmon: II. δ15N and δ13C 

evidence in the Kvichak River watershed, Bristol Bay, southwestern Alaska. Canadian 

Journal of Fisheries and Aquatic Sciences 50: 2350-2365. 

Larkin, G. A. and P. A. Slaney. 1997. Implications of trends in marine-derived nutrient influx to 

south coastal British Columbia salmonid production. Fisheries 22, no. 11: 16-24. 

Michael, J. H., Jr. 1998. Pacific salmon spawner escapement goals for the Skagit River 

watershed as determined by nutrient cycling considerations. Northwest Science 72: 239-

248. 

Minakawa, N. 1997. The dynamics of aquatic insects associated with salmon spawning. Ph.D 

Dissertation, University of Washington, Seattle. 

Naiman, R. J., R, E. Bilby, D. E. Schindler, and J. M. Helfield. 2002. Pacific salmon, nutrients, 

and the dynamics of freshwater and riparian ecosystems. Ecosystems 5: 399-417. 

Piorkowski, R. J. 1995. Ecological effects of spawning salmon on several south central Alaskan 

streams. Ph.D. Dissertation. University of Alaska, Fairbanks. 

Richey, J. E., M. A. Perkins, and C. R. Goldman. 1975. Effects of kokanee salmon 

(Oncorhynchus nerka) decomposition on the ecology of a subalpine stream. Journal of the 

Fisheries Research Board of Canada 32: 817-820. 

Scheuerell, M. D., P. S. Levin, R. W. Zabel, J. G. Williams, and B. L. Sanderson. 2005. A new 

perspective on the importance of marine-derived nutrients to threatened stocks of Pacific 

salmon (Oncorhynchus spp.). Canadian Journal of Fisheries and Aquatic Sciences 62: 961-

964. 

Schmidt, D.C., Carlson, S.R., Kyle, G.B. and Finney, B.P. 1998. Influence of carcass-derived 

nutrients on sockeye salmon productivity of Karluk Lake, Alaska: Importance in the 

assessment of an escapement goal. North American Journal of Fisheries Management 18: 

743-763. 

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Schuldt, J. A. and A. E. Hershey. 1995. Effect of salmon carcass decomposition on Lake 

Superior tributary streams. Journal of the North American Benthological Society 14: 259-

268. 

Stockner, J. G. (ed.). 2003. Nutrients in salmonid ecosystems: sustaining production and 

biodiversity. American Fisheries Society Symposium 34, American Fisheries Society, 

Bethesda, MD. 

Walters, C.J., P. LeBlond, and B.E. Riddell. 2004. Does over-escapement cause salmon stock 

collapse? Technical Paper. Vancouver, B.C. Pacific Fisheries Resource Conservation 

Council. 34 p. 

Wipfli, M.S., J. Hudson, and J. Caouette. 1998. Influence of salmon carcasses on stream

productivity: response of biofilm and benthic macroinvertebrates in southeastern Alaska, 

U.S.A. Canadian Journal of Fisheries and Aquatic Sciences 55:1503-1511. 

Section 7c citations: 

Beamish, R. J., B. E. Riddell, C. M. Neville, B. Thomson, and Z. Zhang. 1995. Declines in 

Chinook salmon catches in the Strait of Georgia in relation to shifts in the marine 

environment. Fisheries Oceanography 43 (3):243-256. 

Beamish, R. J., C. Mahnken, and C. M. Neville. 1997. Hatchery and wild production of Pacific 

salmon in relation to large-scale natural shifts in the productivity of the marine 

environment. ICES Journal of Marine Science 54:1200-1215. 

Bigler, B.S., D. W. Welch, and J. H. Helle. 1996. A review of size trends among North Pacific 

salmon (Oncorhynchus spp.). Canadian Journal of Fisheries and Aquatic Sciences 53:455-

465. 

Bottom, D. 1999. Managing for salmon as if the ocean mattered. P 99 - 117. In G. A. Bisbal (ed). 

Ocean conditions and the management of Columbia River salmon. Northwest Power 

Planning Council 99-11. Northwest Power Planning Council, Portland, Oregon. 

Hard, J. 2004. Evolution of Chinook salmon life history under size-selective harvest. P 315-337. 

In, A. P. Hendry and S. C. Stearns (eds). Evolution Illuminated: salmon and their relatives. 

Oxford University Press. 

HSRG (Hatchery Scientific Review Group - L Mobrand, J Barr, L Blankenship, D Campton, T 

Evelyn, T Flagg, C Mahnken, R Piper, P Seidel, L Seeb, and B Smoker. 2004. Hatchery 

reform: principles and recommendations of the HSRG. Long Live the Kings, 1305 Fourth 

Avenue, Suite 810, Seattle, WA 98101 (available from www.hatcheryreform.org). 

Helle, J. 1989. Relation between size-at-maturity and survival of progeny in chum salmon, 

Oncorhynchus keta (Walbaum). J. Fish. Biol. 35 (Supplement A):99-107. 

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Hilborn, R. and D. Eggers. 2000. A review of the hatchery programs for pink salmon in Prince 

William Sound and Kodiak Island, Alaska. Transactions of the American Fisheries Society 

129:333-350. 

Hilborn, R., and D. Eggers. 2001. A review of hatchery programs for pink salmon in Prince 

William Sound and Kodiak Island, Alaska: Response to comment. Transactions of the 

American Fisheries Society 130:720-724. 

NWPPC (Northwest Power Planning Council). 1986. Hydropower responsibility for salmon and 

steelhead losses in the Columbia River Basin. April 1986, (S/III.A.2). Northwest Power 

Planning Council, Portland, Oregon. 

Levin, P. S., R. W. Zabel, and J. G. Williams. 2001. The road to extinction is paved with good 

intentions: negative associations of fish hatcheries with threatened salmon. P. Roy. Soc. 

Lond. B Bio. 268: 1153-1158. 

Lichatowich, J. 1993. Ocean carrying capacity. Recovery issues for threatened and endangered 

Snake River salmon. Technical Report 6. DOE/BP - 99654-6 

Lichatowich. J, 1999. Salmon without rivers: a history of the pacific salmon crisis. Island Press, 

Washington D.C. 

Peterman, R. 1989. Application of statistical power analysis to the Oregon coho salmon 

(Oncorhynchus kisutch) problem. Canadian Journal of Fisheries and Aquatic Science 

46:1183-1187. 

Peterman. R. and R. D. Routledge. 1983. Experimental management of Oregon coho salmon 

(Oncorhynchus kisutch): Designing for yield of information. Canadian Journal of Fisheries 

and Aquatic Science 40:1212-1223. 

Ruggerone G. T. and F. A. Goetz. 2004. Survival of Puget Sound chinook salmon 

(Oncorhynchus tshawytscha) in response to climate-induced competition with pink salmon 

(Oncorhynchus gorbuscha). Canadian Journal of Fisheries and Aquatic Sciences 61:1756-

1770. 

Ruggerone, G. T., M. Zimmermann, K. Myers, J. Nielsen, and D. Rogers. 2003. Competition 

between Asian pink salmon (Oncorhynchus gorbuscha) and Alaskan sockeye salmon (O. 

nerka) in the North Pacific Ocean. Fisheries Oceanography 12(3):209-219. 

Sweeting, R.M., R.J. Beamish, D.J. Noakes, and C.M. Neville. 2003. Replacement of wild coho 

salmon by hatchery-reared coho salmon in the Strait of Georgia over the past three decades. 

N. Amer. J. Fish. Manage. 23: 492-502. 

Wertheimer, A., W. W. Smoker, T. L. Joyce, and W. R. Heard. 2001. Comment: A review of the 

hatchery programs for pink salmon in Prince William Sound and Kodiak, Alaska. 

Transactions of the American Fisheries Society 130:712-720. 

84 
ISAB 2005-4 Harvest Report 

Section 7d citations: 

 

Gedalof, Z, and D. J. Smith. 2001. Interdecadal climate variability and regime-scale shifts in 

Pacific North America. Geophys. Res. Lett. 28: 1515. 

Hare, S. R., and N. J. Mantua. 2000. Empirical evidence for North Pacific regime shifts in 1997 

and 1998. Progress in Oceanography 47:103. 

IPCC (Intergovernmental Panel on Climate Change). 2001. Climate change 2001: The scientific 

basis. Cambridge University Press. 

Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis. 1997. A Pacific 

interdecadal climate oscillation with impacts on salmon production. Bull. Amer. Meteorl. 

Soc. 78: 1069. 

McPhadden, M. J., and 14 co-authors. 1998. The tropical ocean-global atmosphere observing 

system: a decade of progress. J. Geophys. Res. 103:14169-14240. 

Morishima, G.S. 1999. When is a Fish Not a Fish? Metrics of Exploitation for Chinook Salmon: 

Fish, e-fish, and the Prodigious Proliferation of Acronyms. Unpublished manuscript prepared 

for a modeling workshop convened by the Northwest Indian Fisheries Commission and 

Washington Department of Fish & Wildlife, October 20, 1999. 

Mote, P. W., and 10 co-authors. 2003. Preparing for climate change: the water, salmon and 

forests of the Pacific Northwest. Climatic Change 61:45-88. 

Pulwarty, R.S. and K.T. Redmond. 1997. Climate and salmon restoration in the Columbia River 

basin: the role and usability of seasonal forecasts. Bull. Amer. Metero. Soc. 78(3): 381-397. 

Service, R. F. 2004. As the west goes dry. Science 303:1124-1127. 

Welch, D. W., Y Ishida, and K. Nagasawa. 1998. Thermal limits and ocean migrations of 

sockeye salmon (Oncorhynchus nerka): long-term consequences of global warming. Can. J. 

Fish. Aquat. Sci. 55: 937. 

Section 7e. citations: 

Allee, W. C. 1931. Animal Aggregations. A study in General Sociology. University of Chicago 

Press, Chicago. 

Beverton, R.J.H. and S.J. Holt. 1957. On the Dynamics of Exploited Fish Populations. U.K. Min, 

Agric. Fish., Fish. Invest. (Ser. 2)19:533p. 

Morishima, G.S. 1999. When is a Fish Not a Fish? Metrics of Exploitation for Chinook Salmon: 

Fish, e-fish, and the Prodigious Proliferation of Acronyms. Unpublished manuscript prepared 

85 
ISAB 2005-4 Harvest Report 

for a modeling workshop convened by the Northwest Indian Fisheries Commission and 

Washington Department of Fish & Wildlife, October 20, 1999. 

OCN Work Group. 2000. 2000 Review of Amendment 13 to the Pacific Coast Salmon Plan. Nov 

12, 2000. Available from the Pacific Fishery Management Council, Portland, OR. 

Ricker, W.E., 1954. Stock and Recruitment. J. Fish. Res. Bd. Can. 11:559-623. 

86 
Appendix A. Harvest Management Functions for Three Columbia River Basin StocksHarvest management functions differ between salmon species or sub-groups within a species. The table below describes differences using three examples of Columbia basin salmon runs of varying characteristics: 1) a healthy natural stock (U

2) an ESA-listed stock impacted by ocean fisheries (Snake River fall Chinook); and 3) an ESA-listed stock that is not hafisheries (spring Chinook). For each example, the range of management functions is identified vertically in the table. For 

the responsible institutional entities, legal authorities, decision time frames, and relevant scientific issues and questions a

1. Upriver Bright Fall Chinook 

Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Iss

Define harvest State of Washington RCW... management unit 

Columbia River treatytribes 

Co-management under U.S. v Oregon (OR) 

Are managem

for the structu(e.g., combiniunit for purpos

Columbia River treatytribes, WA, OR, ID

Co-management under U.S. v. Oregon (OR) 

Comply with conservation and allocation obligations 

Establish conservation objectives and constraints for naturallyspawning stocks 

USFWS & NOAAfisheries 

ESA Establish jeopardy 

standards for ESA listed stocks (Snake River fall Chinook and B run Steelhead) which mayaffect or be affected bymanagement of URB, i.e., Snake River fall Chinook, upriver summer Chinook, and steelhead 

Reflected in long-term management plans whensuch exist, otherwise memorialized in annual fishing plan agreements. 

Are conservatobligations adtechnical basiescapement ghas been reviTechnical Comas Snake Riveseparated – thescapement gregardless of How are contnatural spawnAre hatchery determining wobjectives havIs the scientifistandards ade

Establish conservation objectives and production goals for hatchery complexes 

States of WA, OR, ID, USFWS, and tribes operating hatcheryfacilities 

Agencies establish escapement needs and production goals. Production objectives subject to negotiation under U.S. v. OR

May operate under an overall mitigation plan or U.S. v. OR management plan. 

Is hatchery pr

wild productio

87 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Iss

Ocean Fisheries Management (Upriver Bright Fall Chinook) Preseason abundance forecasts 

Prepared by agencies and processed thru Columbia RiverTechnical AdvisoryCommittee (TAC) 

US. V. OR Preliminary expectations 

of the number of fish expected to return to Bonneville Dam, converted to river mouth returns. First forecastsavailable in December, age-specific forecasts in February

What are the the forecasts? forecasts? 

PFMC MFCMA Specified in framework 

management plan

Periodic 

Treaty Troll Tribes U.S. v. WA Intertribal agreements Periodic PSC Pacific Salmon Treaty

Act 

Fishery regimes adopted by PSC establishes international obligations 

Periodic Estimation of 

CDFO Domestic management

objectives within constraints of PSC regimes 

Annual, allowable impacts determined through calibration of CTC Chinook model 

NPFMC & State of Alaska 

Management objectives

within constraints of PSC regimes 

Ditto 

Estimation of 

Establish management objectives and constraints 

NOAAF-NMFS ESA Establish annual

guidance for ESA listed stocks, which may affect management of URB. 

Mar-Apr Scientific basi

PFMC MFCMA Framework Plan, PSC 

Chinook model, Chinook FRAM 

March-April

Treaty Troll Tribes Inherent management 

authority

Negotiated harvest levels March-April 

CDFO Domestic planning

processes 

May-June 

Develop annual management plans 

Alaska Board of Fisheries 

Sector (troll, sport, net) 

allocation schedule for Southeast Alaskan fisheries 

Routine 

Are the modescientifically s

88 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Iss

Ocean Fisheries Management (Upriver Bright Fall Chinook) continued...Approve management plans 

US Secretary of Commerce 

Administrative delegation Compliance with 

National Standards and applicable law

May

In season management to implement regulations 

States of WA, OR, AK, treaty troll tribes, CDFO, NOAAF thru PFMC 

Compliance with

management plans 

Continuous in season Are the in-sea

adequate to clevels? 

States of WA, OR, AK, CDFO, treaty troll tribes 

Provide periodic updates 

of fishery progress 

Continuous in season, postseason report 

Is the reportinseason analyscompleted in a into account in 

Reporting 

Post season report January following

season end 

89 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Iss

In-River Fisheries Management (Upriver Bright Fall Chinook) 

Columbia RiverCompact. For Non-Indian fisheries, OR/WA staff typicallyreview proposals for fisheries and make recs. TAC reviews “fact sheets” and past fisheryharvest data, but does not typically reviewfishery proposals in advance of the conduct of fisheries. 

USC... 

For tribal commercial fisheries, tribes set actual regulations 

Compact adopts regulations authorizing the purchase of fish caught in Indian fisheries by non-Indian residents of WA & OR 

Meet conservation and treaty allocation requirements. TreatyIndian fisheries authorized by enacting regulations that allownon-Indians to purchase Indian fish. 

Aug-Oct In season run 

of run expecteperiodically afcomponents bBPH. BPH discoloration. URadults by size Recent 5-year are assumed. 

Regulate Commercial Fisheries 

NOAA-NMFS ESA Jeopardy standards for 

SRF based on % of river mouth run size. Assuming that SRF is a fixed proportion of URB run. B-run steelhead constraint differs for treaty and nontreatyfisheries. For nontreaty fisheries, B-run impacts are based on preseason estimates of abundance and estimates made through runreconstruction since fish are released. Treatyimpacts are based at % limits of impacts at Bonneville, based on monitoring at Bonneville, based on length (fish>78cm are assumed to be B-Run fish), adclips and scale sampling. 

What is the sc

standards? How valid is thproportion of tSRF wild fish? What is the acforecasts of Bassumptions rIs the separaton size well su

90 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Issues a

In-River Fisheries Management (Upriver Bright Fall Chinook) continued... 

WA/OR workcooperatively, but act separately from the Columbia RiverCompact in setting season, bag limits, etc. States take action in “Joint State Sport Hearings” that function much like the Compact does for commercial fisheries. Joint Columbia River staff reviews sport fishery proposals. Harvest data reviewed by TAC

RCW... RCO... 

Regulate Sport Aug-OctFisheries 

NOAA-NMFS ESA Jeopardy standards for 

SRF based on % of river mouth run size. Assuming that SRF is a fixed proportion of URB run. B-run steelhead constraint based on preseason estimates of abundance since fish are released. 

How valid is the as

the URB run being What is the accuraforecasts of B-run assumptions regar

Post Season Review (Upriver Bright Fall Chinook) Escapement Estimation & reporting 

WDFW, ODFW, Tribes, IFG, NOAA fisheries, USFWS 

Sep-Jan Escapement of UR

composition via CWsampling of spawnreturns. Accuracy ofun components?

Read & report CWT recoveries 

ODFW Agreement Aug-Jan 

In-river run reconstruction 

WDFW. Review by TAC Agreement Jan-Feb Accuracy of dam p

counts minus estimto tributaries)? 

91 
2. Snake River Fall Chinook (Sub-Group) of Upriver Brights 

Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Basis

Define harvest States of WA, OR, ID RCW... management unit 

Columbia River treatytribes 

Co-managementunder U.S. v Oregon 

Are management un

structure of the reprcombining SRF into purposes of harvest 

Columbia River treatytribes 

Co-managementunder U.S. v. Oregon 

Comply with conservation and allocation obligations 

Establish conservation objectives and constraints for naturallyspawning stocks 

NOAA fisheries ESA Establish jeopardy standards 

Reflected in longterm management plans when such exist, otherwise memorialized in annual fishing plan agreements. 

Are conservation obadequately describedocumented? How are contributiospawning escapemstrays accounted fonot escapement objIs the scientific and standards adequate

Establish conservation objectives and production goals for hatchery complexes 

States of WA, OR, ID and tribes operating hatchery facilities

Agencies establish escapement needs and production goals 

May operate under an overall mitigation plan or U.S. v. OR management plan. 

Is hatchery producti

production objective

Ocean Fisheries Management (Snake River Fall Chinook) Preseason abundance forecasts (None – fixed small cohort sizes to estimate exploitation rates)

MSFCMA 

PFMC MFCMA Specified in framework 

management plan

Periodic 

PSC Pacific Salmon

Treaty Act 

Fishery regimes adopted by PSC establishes international obligations 

Periodic Estimation of abund

CDFO Domestic management objectives 

within constraints of PSC regimes

Annual, allowable impacts determined through calibration of CTC Chinook model 

Estimation of abund

NPFMC & State of Management objectives Ditto Alaska With in constraints of PSC 

regimes 

Establish management objectives and constraints 

NOAAF-NMFS ESA Establish annual guidance Mar-Apr Scientific basis for g

Function Responsible Entity Authority Legal constraints and Time frame Scientific Basis

92 
obligations 

Ocean Fisheries Management (Snake River Fall Chinook) continued...

PFMC MFCMA Framework Plan, PSC Chinook 

model, Chinook FRAM, KOHM 

March-April

Treaty Troll Tribes Inherent 

management authority

Negotiated harvest levels March-April 

CDFO Domestic planning processes May-June 

Develop annual management plans 

Alaska Board of Fisheries 

Sector (troll, sport, net) allocation 

schedule for Southeast Alaskan fisheries 

Routine 

Are the models and sound? 

Approve management plans 

US Secretary of Commerce 

Administrative delegation 

Compliance with National Standards and applicable law

May

In-season management to implement regulations 

States of WA, OR, AK, treaty troll tribes, CDFO, NOAAF thru PFMC 

Compliance with management

plans 

Continuous inseason Are the in-season m

constrain impacts to 

Provide periodic updates of fishery progress 

Continuous inseason, postseason report 

Reporting States of WA, OR, AK, 

CDFO, treaty troll tribes 

Post season report January following

season end 

Is the reporting timeseason analyses of in a timely manner sharvest manageme

93 
Function Responsible Entity Authority Legal constraints and obligations Time frame Scientific BasIn-River Fisheries Management (Snake River Fall Chinook) 

Columbia RiverCompact. Proposed fishing schedules reviewed by TAC 

USC... Meet conservation and treaty allocation 

requirements. Treaty Indian fisheries authorized by enacting regulations that allow non-Indians to purchase Indian fish. In-season run size updates based made when 50% of run expected to return (~Sept 10). Run components broken out byURB, MCB, BPH. BPH distinguished from Brights by skin coloration. URB & MCB separates jacks and adults by size with stock separation via CWTs. Recent 5-year average dam conversion rates are assumed. 

Regulate Commercial Fisheries 

NOAA-NMFS ESA Jeopardy standards for SRF based on % of river 

mouth run size. Assuming that SRF is a fixed proportion of URB run. B-run steelhead constraint differs for treaty and nontreaty fisheries. For nontreaty fisheries, B-run impacts are based on preseason estimates of abundance since fish are released. Treaty impacts are based at % limits of impacts at Bonneville, based on monitoring at Bonneville, based on length (fish>78cm are assumed to be B-Run fish), ad-clips and scale sampling 

Aug-Oct 

What is the sstandards? How valid is tproportion of SRF wild fishWhat is the aforecasts of Bassumptions rates?Is the separaon size well s

WA/OR workcooperatively, but act independently in setting season, bag limits, etc. Technical review byTAC 

RCW... RCO... 

Regulate Sport Fisheries 

NOAA-NMFS ESA Jeopardy standards for SRF based on % of river 

mouth run size. Assuming that SRF is a fixed proportion of URB run. B-run steelhead constraint based on preseason estimates of abundance since fish are released. 

Aug-Oct 

How valid is tproportion of SRF wild fishWhat is the aforecasts of Bassumptions rates?

94 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Issues a

Post Season Review (Snake River Fall Chinook)Escapement Estimation & reporting 

WDFW, ODFW, Tribes, IFG 

Sep-Jan Escapements of SR

Dam, trap data, & Lhatchery fish, supporigin fish. SRF wild identical to CWT’d determined from CWBonneville, but not age composition escomposition estimaAccuracy of age co

Read & report CWT recoveries 

ODFW Agreement Aug-Jan

In-river run reconstruction 

WDFW. Review by TAC Agreement Jan-Feb Accuracy of dam pa

counts minus estimto tributaries)? 

3. B-Run Steelhead 

Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Basis

Define harvest States of WA, OR, ID RCW... management unit 

Columbia River treatytribes 

Co-managementunder U.S. v Oregon 

Are management 

structure of the repcomponents)? 

Columbia River treatytribes 

Co-managementunder U.S. v. Oregon 

Comply with conservation and allocation obligations 

Reflected in longterm management plans when such exist, otherwise memorialized in annual fishing plan agreements. 

Are conservation oadequately describdocumented? How are contributispawning escapemstrays accounted fnot escapement o

Establish conservation objectives and constraints for naturallyspawning stocks 

NOAA fisheries ESA Establish jeopardy 

standards 

Is the scientific and 

standards adequa

Establish conservation objectives and production goals for hatchery complexes 

States of ID, USFWS, and tribes operating hatchery facilities

Agencies establish escapement needs and production goals 

May operate under an overall mitigation plan or U.S. v. OR management plan. 

Is hatchery produc

production objectiv

95 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Issues and Que

Ocean Fisheries Management (B-Run Steelhead) (Harvest Presumed Negligible) In-River Fisheries Management (B-Run Steelhead) 

For Non-Indian fisheries, OR/WA staff typically review proposals for fisheries and make recs. TAC reviews “fact sheets” and past fisheryharvest data, but does not typically review fishery proposals in advance of the conduct of fisheries. For tribal commercial fisheries, tribes set actual regulations; the Columbia River Compact adopts regulations authorizing the purchase of fish caught in Indian fisheries by nonIndian residents of WA & OR Tribal terminal fisheries are negotiated with ID. Impacts are included in overall in-river impacts negotiated in U.S. v. OR. 

USC... Meet conservation and 

treaty allocation requirements. TreatyIndian fisheries authorized by enacting regulations that allow non-Indians to purchase Indian fish. 

Aug-Oct Separation of steelhead int

on size (fish >78 cm assumdata suggest that this may separation of A&B run steesupported by data? Steelhead run sizes are onFall season, non-Indian comonitored for total steelheaimpacts estimated using olcomposition model. How aand accounted for in lower In-season run size updates expected to return. Recent rates are assumed. Impacts of tribal commerciare estimated through fisheadjusted by sampling data 

Regulate Commercial Fisheries 

NOAA-NMFS ESA Jeopardy standards for Brun steelhead differ for 

treaty and nontreatyfisheries. For nontreaty fisheries, B-run impacts are based on preseason estimates of abundance since fish are released. Treaty impacts are based at % limits of impacts at Bonneville Dam, based on monitoring at BD, based on length (fish>78cm are assumed to be B-Run fish), ad-clips and scale sampling. Jeopardy stds for B-run steelhead onlyapply during fall fisheries. Impacts during the summer season are not estimated separately for A and B run fish. 

Aug-Oct What is the scientific basis 

How valid is the assumptiorun being comprised of SRWhat is the accuracy of preB-run steelhead and sensitrelease mortality rates? Are estimates of ceremoniahome fish available and of consideration in managem

96 
Function Responsible Entity Authority Legal constraints and 

obligations 

Time frame Scientific Issues and Q

WA/OR work cooperatively, but act independently in setting season, bag limits, etc. Technical review by TAC ID regulates its fisheries independently

RCW... RCO... 

Aug-Oct Sport fisheries for steelh

the release of all fish witB-run fish in mainstem Climited to a specific percimpacts are not estimatecollected in sport fisherieIs the coordination amoninsure that allowable impconstrained? 

Regulate Sport Fisheries 

NOAA-NMFS ESA Jeopardy standards for Brun steelhead constraint 

based on preseason estimates of abundance since fish are released. 

What is the accuracy of 

of B-run steelhead and sregarding release morta

Post Season Review (B-Run Steelhead) Escapement Estimation & reporting 

WDFW, ODFW, Tribes, IFG Sep-Jan Escapement by Lower G

composition via scales tVery little sampling data spawning grounds. Accuracy of age compo

Read & report CWT recoveries 

ODFW Agreement Aug-Jan CWTs are not used for h

used for purposes of ha

In-river run reconstruction 

WDFW. Review by TAC Agreement Jan-Feb A & B run returns are es

and Lower Granite Damrun fish comparable and size & some large fish gand some B run fish are considered B run fish at fisheries; (b) some steewinter when no counts aComplete information is is not estimated. Since no total run reconimpacts evaluated and r

97 
98 

Appendix B. Table of Columbia River Salmonids organized by Ocean, In-River, and ESA Managem

OCEAN FISHERY MANAGEMENT IN-RIVER MANAGEMENT ESU INFORMAT

(1) (2) (2) (3) (4) (4) (4) 

Harvest 

Management Unit 

Ocean Harvest 

Management Objective 

Indicator & 

method 

In River Harvest 

Management Objective Indicator & method ESU Listing Status Description 

Chinook Snake River spring/summer-run Chinook salmon 

Not applicable for ocean fisheries - negligible impact 

Not applicable for ocean fisheries - negligible impact 

Management period January 1 through June 15. Sliding scale harvest rates, depending on status of upriver spring Chinook and Snake River summer Chinook. Ceremonial and subsistence harvest treated separately from commercial and recreational fisheries. 

Dam counts, inseason catch monitoring. Upriver spring Chinook includes all natural and hatchery spring Chinook stocks originating from the Columbia River and its tributaries upstream of Bonneville Dam. Snake River summer Chinook includes all natural and hatchery summer Chinook stocks originating from the Snake River watershed. 

Snake River spring/summerrun Chinook salmon 

Threatened All natural populations 

spring/summer-run Chsalmon using tributarimainstem Snake Rivesubbasins are the TucRiver, Grande Ronde Imnaha River, and SaRiver. Spring/summer introduced into the ClRiver subbasin were efrom the ESU. 

Upriver Springs Ensure that ocean fishery 

impacts remain rare and recognize Columbia River Management Plan Objective 

Not applicable for ocean fisheries - negligible impact 

Same as for Snake River spring/summer Chinook 

Same as for Snake River spring/summer Chinook 

Upper Columbia River spring-run Chinook salmon 

Endangered All naturally spawned 

populations of spring-Chinook salmon in all River tributaries upstrRock Island Dam and downstream of Chief Dam in Washington Stributary subbasins wiruns are the Wenatchand Methow Rivers. 
99 

OCEAN FISHERY MANAGEMENT IN-RIVER MANAGEMENT ESU INFORMAT

(1) (2) (2) (3) (4) (4) (4) 

Harvest 

Management Unit 

Ocean Harvest 

Management Objective 

Indicator & 

method 

In River Harvest 

Management Objective Indicator & method ESU Listing Status Description 

Middle Columbia River spring-run Chinook salmon 

Hold ocean fishery impacts <1% and recognize Columbia River Management Plan objective 

Not applicable for ocean fisheries - negligible impact 

Same as for Snake River spring/summer Chinook 

Same as for Snake River spring/summer Chinook 

Middle Columbia River spring-run Chinook salmon 

Not warranted Naturally spawned po

of spring-run Chinook the Columbia River baupstream of the Wind Washington, and the River, Oregon, to and the Yakima River, excChinook from the Snasubbasins. Major tributhe ESU are the YakimKlickitat, Deschutes, JUmatilla, and Walla WRivers. 

Upriver summer Chinook 

Hold ocean exploitation rates <2% and recognize in-river management objectives 

Wells Hatchery; CTC Chinook Model, PFMC Chinook FRAM 

Management period June 16 through July 31. Hatchery production andnatural spawning escapement goal. Sliding scale of in-river harvest rates depending on in-river run size. 

Dam counts Upper 

Columbia River summer/fall-run Chinook salmon 

Not warranted Naturally spawned po

of summer and fall-ruin streams in the ColuRiver basin upstream including the Yakima the U.S.–Canada bordtributary subbasins in are the Yakima, WenaEntiat, Methow, and ORivers. 

Snake River fall-run Chinook salmon 

NMFS jeopardy or recovery standard. Since 1995, total age-4/4 adult equivalent exploitation rate no greater than 70% of 1988-1993 average for all ocean fisheries combined. 

Lyons Ferry Hatchery Stock; CTC Chinook Model and PFMC Chinook FRAM 

Inriver mainstem nonIndian and treaty Indian fisheries managed under harvest rate limits with a combined impact comparable to a 30% reduction in the age 3/4 adult equivalent exploitation rate for ocean fisheries. 

Dam counts, assumed percentage of total upriver bright run, in-season catch monitoring 

Snake River fall-run Chinook salmon 

Threatened All natural populations 

Chinook salmon in the mainstem Snake RiveTucannon River, GranRiver, Imnaha River, SRiver, and Clearwater subbasins. 
100 

OCEAN FISHERY MANAGEMENT IN-RIVER MANAGEMENT ESU INFORMAT

(1) (2) (2) (3) (4) (4) (4) 

Harvest 

Management Unit 

Ocean Harvest 

Management Objective 

Indicator & 

method 

In River Harvest 

Management Objective Indicator & method ESU Listing Status Description 

Upriver Bright fall Chinook 

40,000 natural bright adults above McNary Dam (increased to 43,000 by Columbia River state and tribal managers) and recognize in-river management objective 

Brights: Priest Rapids Hatchery Stock and Hanford Reach natural stock; 

40,000 escapement goal at McNary Dam plus production goals for Spring Creek National Fishery, Klickitat Hatchery, Little White Salmon Hatchery, and Mid-Columbia Bright Fall Chinook which are not treated as management constraints. 

Dam counts, assumed percentage of total upriver bright run, skin coloration, run timing, in-season catch monitoring 

Upper Columbia River summer/fall-run Chinook salmon 

Not warranted Naturally spawned po

of summer and fall-ruin streams in the ColuRiver basin upstream including the Yakima the U.S.–Canada bordtributary subbasins in are the Yakima, WenaEntiat, Methow, and ORivers. 

Deschutes River summer/fall-run Chinook salmon 

None None Managed as part of 

upriver bright complex with special consideration for escapement of Deschutes River component. 

Dam counts, assumed percentage of total upriver bright run, skin coloration, run timing, in-season catch monitoring 

Deschutes River summer/fall-run Chinook salmon 

Not warranted Naturally spawned po

of summer and fall-ruin the Deschutes Rive
101 

OCEAN FISHERY MANAGEMENT IN-RIVER MANAGEMENT ESU INFORMAT

(1) (2) (2) (3) (4) (4) (4) 

Harvest 

Management Unit 

Ocean Harvest 

Management Objective 

Indicator & 

method 

In River Harvest 

Management Objective Indicator & method ESU Listing Status Description 

Steelhead 

Managed in accordance with annual in-river modeling results. 

A-Run Steelhead (fish smaller than 78 cm, primarily returning to Snake, Salmon, Grande Ronde, Imnaha Rivers 

None - negligible ocean 

fishery impacts 

None - negligible ocean fishery impacts 

Managed in accordance with annual in-river modeling results. Separate harvest rate constraints on wild B-run steelhead for non-Indian fisheries outside the Snake River and Treaty Indian Zone 6 fisheries. 

B-Run Steelhead (fish returning after August 25th and larger than 78 cm fork length and passing Bonneville Dam between July 1 and October 31), primarily returning to Clearwater and Salmon Rivers 

Snake River basin steelhead 

Threatened All naturally spawned 

populations of steelheSnake River basin. Mtributary subbasins in are the Tucannon, CleGrande Ronde, ImnahSalmon Rivers. 

None None - negligible ocean 

fishery impacts 

None Expected in-river

mainstem harvest rates up to 3.4% 

Upper 

Columbia River steelhead 

Endangered Naturally spawned po

of steelhead in streamColumbia River basin of the Yakima River to Canada border. Majosubbasins in this ESU Wenatchee, Entiat, Mand Okanogan Rivers
102 

OCEAN FISHERY MANAGEMENT IN-RIVER MANAGEMENT ESU INFORMAT

(1) (2) (2) (3) (4) (4) (4) 

Harvest 

Management Unit 

Ocean Harvest 

Management Objective 

Indicator & 

method 

In River Harvest 

Management Objective Indicator & method ESU Listing Status Description 

None None - negligible ocean 

fishery impacts 

None Non-Indian in-river

mainstem fisheries subject to a harvest rate constraint; treaty Indian fishery impacts on winter-run steelhead considered negligible. 

Dam counts, inseason catch monitoring 

Middle Columbia River steelhead 

Threatened Naturally spawned po

of steelhead in the CoRiver basin upstream Wind River, Washingtthe Hood River, Oregincluding the Yakima except for steelhead fSnake River subbasintributaries in the ESU Yakima, Klickitat, DesJohn Day, Umatilla, aWalla Rivers. 

Sockeye None None - negligible ocean 

fishery impacts 

None Escapement goal for 

adult sockeye at Priest Rapids Dam. Non-Indian in-river harvest rate fixed constraint. Treaty Indian fishery harvest rates regulated on sliding scale depending on upriver sockeye run size.

Dam Counts, separation of Snake River and Columbia River stocks 

Snake River sockeye salmon 

Endangered The only extant popul

the anadromous form Redfish Lake populatHistorically, sockeye rfound in the Stanley RPayette Lake, Warm LWallowa Lake. 

None None - negligible ocean 

fishery impacts 

None Same as above Dam Counts, 

separation of Snake River and Columbia River stocks 

Okanogan River sockeye salmon 

Not warranted Naturally spawned po

of sockeye salmon in Lake and its U.S. tribuand the U.S. portion oSimilkameen River. 

None None - negligible ocean 

fishery impacts 

None Same as above Dam Counts, 

separation of Snake River and Columbia River stocks 

Lake Wenatchee sockeye salmon 

Not warranted Naturally spawned po

of sockeye salmon in Wenatchee and its triincluding the White anWenatchee Rivers. 
103 

OCEAN FISHERY MANAGEMENT IN-RIVER MANAGEMENT ESU INFORMAT

(1) (2) (2) (3) (4) (4) (4) 

Harvest 

Management Unit 

Ocean Harvest 

Management Objective 

Indicator & 

method 

In River Harvest 

Management Objective Indicator & method ESU Listing Status Description 

Coho 50% of the harvestable 

upriver adult coho (south of the US-Canada border) available to fisheries above Bonneville Dam (PFMC requirement). 

Prorated proportion of forecast abundance of Columbia River Early and Late Stocks derived from Coho FRAM model 

Meet requirements for brood stock escapement necessary to meet Columbia River hatchery production goals. Natural spawning escapement goal to be developed and incorporated into a new Columbia River Fish Management Plan. 

Dam counts None NA NA 

White Sturgeon None NA Annual review of sturgeon management 

issues results in reservoir-specific annual harvest constraints. 

None None NA NA 

(1) Commonly used name for harvest management unit (2) Except for coho (PFMC requirement) and sturgeon, Appendix A of NMFS FPEIS for Ocean Fisheries. (3) PSC Chinook Technical Committee (4) Independent Populations of Chinook, Steelhead, and Sockeye for Listed Evolutionarily Significant Units Within the Interior Columbia River Basin Domain. Interior ColJuly 2003. 
ISAB 2005-4 Harvest Report 

Appendix C. Supplement to Questions, Section 6; Reductions in Fishery 

Impact Rates for Three Columbia River Salmon Populations 

The distinction between the terms harvest rate and exploitation rate is important to understand 

when reviewing these examples. 

Harvest rate refers to the proportion of a population available to a fishery that is killed by 

that fishery. Harvest rates are most frequently used to quantify impacts of terminal area 

fisheries, such as those conducted on fish returning to the Columbia River on their 

spawning migration. Qualifiers are used to describe the type of proportion involved. For 

example, for a net fishery in the Columbia River, the age 4, reported catch harvest rate

on URBs would represent the ratio between the numbers of age 4 URBs reported as being 

caught by that fishery divided by the terminal run size of age 4 URBs. 

In contrast, the term Exploitation rate refers to the proportion of an entire population that 

is killed by a fishery. Exploitation rates are most frequently used to quantify fishery 

impacts in ocean fisheries because the proportion of fish available to those fisheries is 

unknown. Both the proportion and the population involved are commonly described by 

the use of qualifiers. For example, an adult equivalent, brood year, total mortality 

exploitation rate represents the ratio between a numerator which consists of total fishing 

mortality (landed catch plus non-landed mortality) expressed in terms of adult 

equivalents24 (the number of fish killed by fishing converted to potential numbers of 

adults) divided by the total number of adults that could be produced from the spawning 

escapement of a given stock and brood year. Similarly, an age 3, reported catch 

exploitation rate for fishery X represents the ratio between the number of age 3 fish from

a given stock reported as being caught in fishery X divided by the total number of age 3 

fish in that stock before fishery X occurs. 

Columbia River Up-River Bright Fall Chinook

Adult equivalent (AEQ) brood year exploitation rates on the CWT indicator stock (Priest Rapids 

Hatchery fingerling releases) for Columbia River Up-River Bright Fall Chinook (URB) are 

depicted in Figure C-1. Three sources of fishing mortality are depicted: (a) the dark bar 

represents the AEQ exploitation rate for reported catch in all ocean fisheries; (b) the crosshatched middle bar represents the AEQ exploitation rate for all in-river fisheries; and (c) the top 

portion of the bars represents the AEQ exploitation rate for incidental (non-catch) fishing 

mortality. AEQ Brood year exploitation rates are rarely employed as the basis for harvest 

management, but are commonly used to monitor impacts of fisheries in relation to stock 

productivity (see discussion in Background section 7e, and Morishima 1999). 

 

24 Since Chinook salmon are harvested at various ages and stages of maturity, exploitation rates are commonly 

expressed in terms of adult equivalents for this species to provide a consistent basis for monitoring fishery impacts 

over time. Adult equivalents are derived by multiplying the number of fish from a given stock and age harvested by

a particular fishery by the appropriate adult equivalence factor, the probability that a fish that is alive at a given age 

would survive to return to its river of origin to spawn in the current or any future year, in the absence of fishing. 

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ISAB 2005-4 Harvest Report 

The data employed to generate Figure C-1 is derived from coded-wire-tag (CWT) releases of the 

exploitation rate indicator stock for URBs, fingerling releases from the Priest Rapids Hatchery. 

An indicator stock is consistently tagged to provide a means of monitoring changes in fishery 

impacts over time; this is particularly important for management of Chinook salmon because 

stock-age-fishery specific estimates of fishing mortality are otherwise extremely difficult and 

costly to obtain for the highly mixed stock fisheries in which this species is intensively exploited. 

The time series of data from CWT indicator stocks provides the only available source of 

historical data available to estimate changes in fishing mortality over an extended period of time. 

Prior to enactment of the Magnuson-Stevens Fishery Conservation and Management Act 

(MSFCMA) in 1976, there was no capacity to constrain exploitation by ocean fisheries outside 

state territorial waters. Consequently, ocean fishery exploitation rates were simply the result of 

the fishing effort that was exerted, and fisheries inside state territorial waters bore the brunt of 

the responsibility for resource conservation. When the MSFCMA was enacted, regional fishery 

management councils were established within the United States to develop measures to regulate 

ocean fisheries within the fishery conservation zone (3-200 miles offshore). But there was still 

no capacity to constrain total impacts on far-north migrating stocks because Canadian fisheries 

were also impacting the same stocks. 

In the early 1980’s, the United States and Canada were engaged in bilateral negotiations to 

develop an international treaty that would constrain interceptions (the harvest of salmon 

originating in one country by fisheries conducted by the other) of salmon. During those 

deliberations, analysis of available coded-wire-tag (CWT) data revealed that the lack of adequate 

constraints on harvests throughout the migratory range of individual stocks had created an 

imminent conservation problem for Chinook salmon. Fishery impacts were increasing while 

spawning escapement levels plummeted. CWT data for URBs were employed in bilateral 

technical analyses that determined that substantial reductions in fishery exploitation rates were 

necessary to stop declining trends in spawning escapements and rebuild depressed stocks. 

Ultimately, the need to establish a coastwide approach for rebuilding depressed stocks of

naturally spawning Chinook salmon proved to be pivotal in the capability of the United States 

and Canada to reach agreement on the Pacific Salmon Treaty (PST) in 1985. 

During the final stages of the negotiations, CWT data indicate that the exploitation rates on 

URBs approached 80% in the mid-1980s. Now, total mortality AEQ brood year exploitation 

rates have been reduced to about 45%. Both ocean and in-river exploitation rates have been 

reduced due to a combination of the Pacific Salmon Treaty and the effects of listing Snake River 

Fall Chinook (a component of the URBs) under the Endangered Species Act (ESA) in May 1992. 

The ESA jeopardy standard for Snake River Fall Chinook, depends upon the level of 

coordination between fisheries, but is generally expressed as a 30% reduction on age 3/4 total 

adult equivalent fishing mortality exploitation rates from the level observed in 1988-1993. 

Exploitation rates by ocean fisheries have been reduced by from 25-30% for brood years of the 

mid-1980s to about 15%-20% for more recent broods. 

As useful as AEQ brood year exploitation rates may be for comparing fishery exploitation rates 

in relation to stock productivity, these metrics are not commonly employed for harvest 

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management. Harvest for fisheries impacting Columbia River Chinook salmon occurs annually 

and involves fish from many brood years simultaneously. 

1975-1998 Brood Year Adult Equivalent Exploitation R

For Columbia River UpRiver Bright Fall Chinook

ates

Exploitation

Rate

0.8

0.9

0.7

0.5

0.6

0.4

0.3

0.2

0.1

0

1975 1980 1985 1990 1995

Year

Ocean InRiver Incidental Mortality

Figure C-1. 1975-1998 Brood Year Adult Equivalent Exploitation Rates for URBs, data from PSC 

document, TCCHINOOK (04)-4, Dec. 31, 2004. (www.psc.org/pubs/) 

Ocean fisheries operate on a mixture of immature and maturing fish and are managed to try to 

constrain exploitation rates so that the appropriate escapement of mature fish results. For URBs, 

these mature fish are of various ages, which were produced by spawning escapements from

several brood years. 

Once fish escape highly mixed stock ocean fisheries, they return to their rivers on their spawning 

migrations. At this point, fewer stocks are involved and it is often possible to separate out 

individual complexes for harvest management. 

Figure C-2 illustrates that in-river fishery harvest rates on URBs have fluctuated, but remained 

relatively stable. One of the objectives for the Pacific Salmon Treaty’s (PST) coastwide Chinook 

rebuilding program was to provide stability for fisheries in terminal areas. For many stocks, 

terminal fisheries had been severely curtailed for several years in response to escalating impacts 

of ocean fisheries; further, impacts on naturally spawning fish had been reduced to by-catch 

during fisheries directed at other stocks and species. Figure C-2 depicts impacts of in-river 

fisheries on an annual basis for URBs. Five types of information are presented: (a) the crosshatched bars reflect the URB terminal run size (number of adult fish entering the Columbia 

River); (b) the solid bars reflect URB spawning escapements; (c) the dotted line represents the 

URB spawning escapement goal; (d) the solid line represents the in-river harvest rate; and (e) the 

dashed line represents Bonneville-McNary Dam passage mortality rate (expressed as a 

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ISAB 2005-4 Harvest Report 

proportion of fish escaping fisheries). Dam passage mortalities can be significant (occasionally 

exceeding 30%) and are additional factors that are taken into account in harvest management. 

Prior to the mid 1980s when agreement on the PST was reached, spawning escapement levels 

were well below the established goal. Since that time, spawning escapements have rarely failed 

to achieve the goal even though in-river harvest rates have fluctuated in response to adjustments 

of fisheries in response to in-season data on abundance and harvest. 

The in-river harvest rate depicted in Figure C-2 represents the proportion of the terminal run that 

is killed by in-river commercial and recreational fisheries. In contrast to the AEQ brood year 

exploitation rates depicted in Figure C-1, the data depicted in C-2 present annual data. Over 

much of the time series, the figure illustrates application of a harvest strategy based on 

escapement goal management (see Background section 7e). From 1990-1995, the in-river harvest 

rates were decreased in order to meet the escapement goal. Since then, terminal run sizes have 

increased, but in-river harvest rate decreased in response to declining run sizes. In recent years, 

in-river harvest rates have not increased to the extent supportable by the URB stock because of 

jeopardy standards established in response to concerns for fishery impacts on the ESA listed 

Snake River Fall Chinook stock. As a result, spawning escapements for this stock have exceeded

the escapement goal established for this stock, preventing the harvest of otherwise harvestable 

URBs and commingled stocks. 

Columbia River Upriver Bright Fall Chinook

Terminal Run Size, Spawning Escapement, and InRiver Harvest Rate For 1975-2003 

(data: TCCHINOOK04-2, Table B.5 and data from Columbia River TAC)

0

50

100

150

200

250

300

350

400

450

1975 1980 1985 1990 1995 2000

Year

Adults (Thousands)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

In River Harvest Rate

Sp Esc Terminal Run InRiver HR DamPassage

Figure C-2. 1975-2003 Annual Terminal Run Sizes, Spawning Escapement, Escapement 

Past Fisheries, and In-River Fishery Harvest Rates on URBs. 

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The fishery impacts depicted in Figure C-2 are due to a combination of management directed at 

reducing ocean and in-river fishery harvest rates and annual variations in abundance. Survival 

rates for URBs have exhibited substantial variability over the time series of available data. 

Figure C-3 depicts survival rate indices derived from releases of the indicator stock for URBs, 

CWT fingerling fall Chinook from Priest Rapids hatchery. The index (average = 1) shows a 

distinct downward trend, periods of depression and high interannual variability. Trends and 

extended periods of depressed survival suggest a potential need to adjust harvest management 

strategies to protect productivity (see Background section 7e) and respond to annual variability 

in stock conditions. 

1975-1997 Brood Year Survival Index

Columbia River UpRiver Bright Fall Chinook

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1975 1980 1985 1990 1995

Brood Year

Survival Index

Figure C-3. Survival Index for CWT Indicator Stock for URBs. 

Impacts of harvest management on the ESA listed Snake River Fall Chinook stock are depicted 

in Figures C-4 and C-5 which present data comparable to those for URBs. The Snake River stock 

is one component of the total URB complex. Fishery impacts on Snake River Fall Chinook are 

monitored through the use of fingerling releases from the Lyons Ferry Hatchery. 

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1984-1998 Brood Year Adult Equivalent Exploitation Rates 

For Natural Snake River Fall Chinook CWT Indicator

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1975 1980 1985 1990 1995

Year

E

xploitation Rate

Ocean InRiver Incidental Mortality

Figure C-4. 1984-1998 Brood Year Adult Equivalent Exploitation Rates or Snake River Fall 

Chinook (CWT indicator stock – Lyons Ferry fingerling releases). TCCHINOOK(04)-4

f

 

Lyons Ferry fingerling releases were not tagged consistently, so a complete time series is 

unavailable. Further, recoveries of these releases are sparse compared to those from Priest

Rapids releases used for URBs because survivals are relatively poor. Figure C-4 indicates that 

AEQ brood year exploitation rates have declined substantially from a level approaching 70% in 

the mid 1980s to about 20% for the most recently available brood year. 

Figure C-5 shows that in-river fishery harvest rates have been reduced markedly from about 60% 

in the mid 1980s to about 20% in more recent years. The ESA jeopardy standard calls for a 

31.29% limit on in-river harvest rates (comparable to the 30% reduction in harvest rates from the 

1988-1993 average established for ocean fisheries)25. Terminal run sizes and spawning 

escapements for Snake River Fall Chinook have steadily increased since the late 1990s. 

Bonneville-Lower Granite Dam passage mortality rates (expressed as a proportion of escapement 

past fisheries) for Snake River Fall Chinook are much higher than for URBs, frequently 

exceeding 50% since 1986. 

25 Biological Opinion on Impacts of Treaty Indian and Non-Indian Fall Season Fisheries in the Columbia River 

Basin in Year 2004, on Salmon and Steelhead Listed Under the Endangered Species Act. NMFS Consultation 

F/NWR/2004/00825. August 6, 2004. Biological Opinion on Impacts of Treaty Indian and Non-Indian Fisheries in

the Columbia River Basin in Years 2005-2007, on Salmon and Steelhead Listed Under the Endangered Species Act, 

Conference on Lower Columbia Coho, and Magnuson-Stevens Act Essential Fish Habitat Consultation. 

Consultation Number: F/NWR/2005/00388. May 9, 2005.

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ISAB 2005-4 Harvest Report 

1986-2003 Snake River Natural Origin Fall Chinook

Terminal Run Size, Spawning Escapement, and InRiver Harvest Rate

 (data: Columbia River TAC Run Reconstruction)

0

2000

4000

6000

8000

10000

12000

14000

16000

1986 1991 1996 2001

Year

Adults

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

In River Harvest Rate

Sp Esc Term Run In River HR DamPasssage

Figure C-5. 1986-2003 Terminal Run Size, Spawning Escapemen s, and In-River Harvest Rates 

for Snake River Fall Chinook. 

t

Although the Snake River stock is considered a component of the URBs, available data indicate 

that fishery impacts differ significantly in both ocean and in-river fisheries. CWT recovery data 

indicate that the Priest Rapids stock is a far-north migrating stock with ocean harvests 

predominantly occurring in northern British Columbia and Southeast Alaska. In contrast, 

recoveries for Lyons Ferry fingerling releases indicate that the Snake River fall Chinook stock is 

harvested by fisheries ranging from central California to Southeast Alaska. Available 

information also indicate that in-river fisheries affect Snake River fall Chinook differently from

URBs, with the Snake River component exhibiting much greater reductions in in-river harvest 

rates. Further investigation would be required to identify the reasons for these differences. An 

important point to keep in mind is that the components of large stock complexes can exhibit 

significant differences that need to be identified and taken into account in harvest management. 

Columbia River Coho

In contrast to Chinook salmon, Columbia River coho mature and are harvested predominantly as 

three-year-old fish. Consequently, interpretation of exploitation rates for this species can avoid 

complications like AEQs and brood year/calendar year differences. 

Estimates of fishery impacts for Columbia River coho are available for a thirty-five year period 

beginning in 1970. Figure C-6 depicts three time series: (a) total mortality (catch plus non-catch) 

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ISAB 2005-4 Harvest Report 

exploitation rates for ocean and in-river fisheries combined are represented by the topmost heavy 

line; (b) total mortality exploitation rates for ocean fisheries represented by the line with round 

markers; and (c) in-river fishery harvest rates (the proportion of fish returning to the Columbia 

River that is killed by fisheries in the Columbia River) are represented by the dashed line. 

Fishery Exploitation/InRiver Harvest Rates

For Columbia River Coho Salmon 1970-2004

(data courtesy of ODFW, May 2005)

0.0

0.2

0.4

0.6

0.8

1.0

1970 1974 1978 1982 1986 1990 1994 1998 2002

Year

Exploitation/In-River Harvest Rate

Ocean ER In Riv HR Total ER

Figure C-6. 1970-2004 Exploitation and Harvest Rates for Columbia River coho.

 

Although suitable CWT data are available for much of the time period covered in Figure C-6, the 

ocean fishery exploitation rates depicted are estimated from a surrogate represented by the 

Oregon Production Index (OPI). The OPI is an index that consists of the sum of the ocean 

catches of all coho salmon harvested south of Leadbetter Point, Washington plus the numbers of 

fish returning to the Columbia River and Oregon coastal rivers. The OPI is considered an index 

because: (1) some of the coho caught south of Leadbetter Point originate from rivers north of 

Leadbetter Point or in California; and (2) Columbia River and Oregon coastal coho are also 

harvested north of Leadbetter Point. The exploitation rate is simply the ocean catch in a given 

year divided by the OPI. 

The use of a single exploitation rate to characterize the harvest of Columbia River coho is 

inaccurate and can be misleading. There are two distinct types of coho produced by the 

Columbia River, termed early and late due to their relative timing of river entry26 on their 

26 Due to its timing, the late run can be harvested by in-river fisheries with fewer concerns for impacts on Chinook. 

Hatcheries in the lower Columbia River produce Chinook that are predominantly north-migrating, hence 

Washington’s fisheries receive greater benefits than Oregon’s. Consequently, Washington has a greater self-interest 

in separating harvest management of coho and Chinook. Not surprisingly, to meet constituency needs, Oregon

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spawning migrations, and it is extremely likely that these types are experiencing different 

exploitation rates in both ocean and in-river fisheries. The ocean distribution of the early run is 

more southerly than the late run. The PFMC manages ocean fisheries north and south of Cape 

Falcon, Oregon to meet objectives for different stocks. South of Cape Falcon, the primary 

objective for coho management is directed at naturally spawning fish from Oregon coastal rivers. 

North of Cape Falcon, coho are managed to meet spawning escapement objectives and treaty 

Indian harvest allocation requirements for individual populations of coho originating from

Washington Coastal and Puget Sound rivers; in addition, coho management in this area is also 

constrained by conservation concerns for coho stocks originating in Southern British Columbia 

under the provisions of agreements reached by the Pacific Salmon Treaty.

The history of exploitation of Columbia River coho illustrates a well-known problem arising 

when complex mixtures of stocks with different productivities are harvested intensively by 

mixed-stock fisheries (Background section 7e). Pursuant to the construction of several dams on 

the Columbia River system, numerous hatcheries were constructed to mitigate for habitat loss. 

These hatcheries released large numbers of coho, which were harvested along with naturally 

spawning coho by both ocean and in-river fisheries. Fishery exploitation rates were constrained 

only by the need to allow sufficient numbers of fish to return to hatchery facilities to meet egg 

take needs. Ocean fisheries exerted exploitation rates that frequently exceeded 80% until the 

early 1980s, and total exploitation rates of over 90% were sometimes observed. 

Naturally spawning stocks were harvested along with hatchery fish by mixed-stock ocean and inriver fisheries. Because these natural stocks had lower productivities, they were unable to sustain 

the exploitation rates being exerted on the hatchery fish. Over time, naturally spawning coho 

populations were virtually extirpated from the Columbia River (save for very small remnant 

populations that are now candidate species being considered for listing as a threatened species 

under the ESA). 

In the early 1980s, alarms for the conservation of Oregon Coastal natural (OCN) coho stocks 

were sounded as spawning escapements plummeted. Ocean fisheries were exploiting these stocks 

at rates in excess of 80%. Concurrently, litigation brought by the Hoh, Quinault, and Quileute 

Tribes (located along the Washington coast) clarified the obligation of the Secretary of 

Commerce to regulate mixed stock ocean fisheries on a river-by-river, run-by-run basis in order 

to satisfy legal obligations under Indian treaties with the United States.27 In response to 

conservation concerns and legal obligations, the Pacific Fishery Management Council 

substantially reduced exploitation rates of ocean commercial and recreational fisheries. The 

effect of these actions is evidenced by the dramatic reduction in ocean fishery exploitation rates 

in Figure C-6. By reducing ocean fishery exploitation rates, more fish became available to 

fisheries in the Columbia River so in-river harvest rates increased (dashed line, Fig. C-6). 

 hatcheries produce predominantly early run fish while Washington hatcheries produce more late run than early run 

fish. 

27 Hoh v. Baldrige, 605 F. Supp 833 (W.D. Wash. 1985). 

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ISAB 2005-4 Harvest Report 

The history of harvest management of Columbia River coho provides a useful illustration of how 

conservation requirements to protect natural stocks can affect the exploitation of commingled 

hatchery fish. In 1990, Oregon Trout filed a petition for listing coho salmon under the ESA, 

claiming excessive exploitation by commercial and recreational fisheries as a contributing 

factor.28 Following a status review, in 1991 the National Marine Fisheries Service (NMFS) was 

unable to identify any indigenous population of naturally spawning coho in the Columbia River 

that warranted protection, i.e., these populations had been extirpated by a combination of 

hatchery stock transfers, habitat degradation, and overfishing.29 Oregon Trout filed another 

series of petitions in 1993 asking that 40 coho salmon populations be listed under the ESA, 

including coho from the Clackamas River. A formal status review was completed in 1995 (see 

footnote 25) which concluded that no naturally spawning coho populations from the Columbia 

River warranted listing, but left the issue open for reconsideration if new information became

available.30 Naturally spawning coho from the lower Columbia River are now proposed for 

listing as a threatened species under the federal ESA.31 The Oregon Fish and Wildlife 

Commission (OFWC) listed lower Columbia River wild coho salmon as an endangered species 

under Oregon’s threatened and endangered species statute in July 1999. 

Since 1984, the harvest of Columbia River coho in mixed stock ocean fisheries has been driven 

by exploitation rates that are determined by the annual status of OCN coho under the Pacific 

Fishery Management Council’s Salmon Framework Plan (FMP). In 1984, the FMP was amended 

to establish a fixed MSY escapement goal of 200,000 spawners for OCN coho. Because of 

concerns for economic dislocations of the commercial and recreational fisheries at low 

abundance, Amendment 7 to the FMP allowed deviations from the fixed escapement goal policy 

in 1987 when OCN abundance dropped below 400,000 fish. In 1993, Amendment 11 to the FMP 

revised the MSY escapement goal to 42 fish per mile and established an exploitation rate limit of 

20% at OCN abundances below 250,000 fish. These measures proved insufficient to halt the 

decline in OCN stocks. In the early 1990s, various petitions were filed to list OCN coho under 

the ESA. Oregon developed a Coastal Salmon Restoration Initiative and PFMC-FMP amended 

its FMP in 1997 (Amendment 13) by establishing a sliding scale of exploitation rates ranging 

 

28 NMFS 1995. Status Review of Coho Salmon from Washington, Oregon, and California. NOAA Tech

Memorandum NMFS-NWFSC-24. September 1995. 29 NMFS. Endangered and threatened species: Lower Columbia River coho salmon. Fed. Reg. 56(124):29553-

29554. 30 “The Clackamas River produces moderate numbers of natural coho salmon. The Clackamas River late-run coho

salmon population is relatively stable under present conditions, but depressed and vulnerable to overharvest. Its 

small geographic range and low abundance make it particularly vulnerable to environmental fluctuations and 

catastrophes, so this population may be at risk of extinction despite relatively stable spawning escapements in the 

recent past. As noted above, the BRT (Biological Review Team) could not reach a definitive conclusion regarding 

the relationship of Clackamas River late-run coho to the historic Columbia River ESU (Evolutionarily Significant

Unit). However, the BRT did conclude that if the Clackamas River late-run coho salmon is a native run that

represents a remnant of a lower Columbia River ESU, the ESU is not presently in danger of extinction, but is likely 

to become so in the foreseeable future if present conditions continue.” NMFS 1995, fn 3. 

31 Even though lower Columbia River natural coho are not presently listed under the ESA, a May 2005 biological 

opinion established a 6.5% in-river harvest rate limit for non-Indian fisheries in the lower Columbia River (no limit 

was established for treaty Indian fisheries because they do no operate in the lower Columbia). Biological Opinion on

Impacts of Treaty Indian and Non-Indian Fisheries in the Columbia River Basin in Years 2005-2007, on Salmon and

Steelhead Listed Under the Endangered Species Act, Conference on Lower Columbia Coho, and Magnuson-Stevens

Act Essential Fish Habitat Consultation. Consultation Number: F/NWR/2005/00388. May 9, 2005. 

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ISAB 2005-4 Harvest Report 

from zero to a high of 45%. Exploitation rates are triggered by forecasts of abundance and 

historical escapement patterns. OCN coho were ultimately listed under the ESA in 1998. 

In addition to reductions in mixed stock exploitation rates, Amendment 13 provided for: 

improved stock assessment program (to provide data to monitor stock response and trigger 

adjustments to management strategies if stocks responses fail to meet expectations); and, a multiyear review of performance. The review was completed in 200032 by representatives of the 

PFMC’s Scientific and Statistical Committee and Salmon Technical Team, representatives from

the Washington and Oregon Departments of Fish & Wildlife, and a Multidisciplinary Science 

Team appointed by the Governor of Oregon. 

Managers subsequently turned to mark-selective fishing because constraints imposed to protect 

OCN coho severely curtailed the ability of ocean fisheries to catch more abundant Columbia 

River hatchery coho. Under this concept, the adipose fins of fish produced by hatcheries are 

removed to provide a visible mark to distinguish hatchery from wild fish. Mark-selective 

fisheries are then employed under regulations that allow the retention of marked hatchery fish, 

but require the release of unmarked fish. Because some of the released fish survive, the harvest 

of hatchery fish can be increased while maintaining the same impact on wild fish of conservation 

concern. To illustrate, suppose that a fishery operates on a population comprised of 1000 wild 

fish and 10,000 marked hatchery fish, that the wild fish can only be harvested at a 10% rate, and 

that 20% of the fish released die. Without mark selective fisheries, 100 wild and 1000 hatchery 

fish could be taken. With mark-selective fishing, however, the allowable mortality rate can be 

maintained by releasing 500 wild fish (100 = 500 x 0.20 = number of wild mortalities); with a 

50% contact rate permitted, 5,000 hatchery fish could be retained. In this example, the 

exploitation rates on wild and hatchery fish under mark-selective fishing would be 10% and 

50%, respectively. In practice, harvest management involving mark-selective fisheries is more 

complex than implied by this simple example, but the basic concept is still the same. 

The PFMC and state managers have employed mark selective fisheries on coho salmon since the 

late 1990’s. Before such fisheries, the magnitude and trends of ocean fishery exploitation rates 

on OCN coho could be directly inferred from exploitation rates on Columbia River hatchery 

coho. In recent years, ocean fishery exploitation rates on OCN coho have been lower than the 

rates depicted in Figure C-6 for Columbia River coho because of mark selective fishing. 

B-Run Steelhead

Unlike Chinook URBs and coho, Columbia River steelhead originating in the Snake River are 

not significantly impacted by ocean fisheries. Nonetheless, they are still harvested by mixed 

stock fisheries in-river (Appendix B, provides information on the stock structure of management 

units), including some listed under the ESA.33 Snake River steelhead are considered summer run 

fish based on their June-October timing of entry into the Columbia River. Snake River steelhead 

 

32 2000 Review of Amendment 13 To the Pacific Council’s Salmon Plan. OCN Workgroup. 

(http://www.pcouncil.org/salmon/salother/ocn1102.pdf) 33 Five Columbia River steelhead ESUs are currently listed: Upper Columbia River, Lower Columbia River, Upper

Willamette River, Middle Columbia River, and Snake River. 

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ISAB 2005-4 Harvest Report 

were listed as threatened under the ESA on August 18, 1997 (Federal Registry 62:43937-43954) 

following a petition filed by the Oregon Natural Resources Council in 1994. 

Management of Snake River steelhead is heavily dependent on assumptions. Snake River 

steelhead are classified as being A-Run or B-Run, based on a bi-modal pattern of passage over 

Bonneville Dam. A-run fish pass Bonneville from June to August and are small, believed to be 

comprised principally of fish that spend only a single year in the ocean. B-Run fish pass 

Bonneville from August through October and are larger fish that spend at least two years in the 

ocean. Two criteria are usually employed to distinguish between A and B-Run fish. Steelhead 

passing Bonneville Dam after August 25 are considered to be from the B-Run, while those 

passing before that date are considered to be from the A-Run. Steelhead are also classified as 

being A or B Run fish, depending on size, with fish larger than 78 cm considered B-Run. Data to 

evaluate the ability of these criteria to accurately identify A and B-Run fish are sparse. Above 

Bonneville Dam, the bimodal migration pattern is not evident; further, the relationship between 

spawning populations and migratory behavior or size differences has not been demonstrated.34 

Because of uncertainties regarding the management basis, the recently completed “2005-2007 

Interim Management Agreement for Upriver Chinook, Sockeye, Steelhead, Coho, and White 

Sturgeon” between Columbia River treaty tribes, the States of Washington, Oregon, and Idaho, 

and Federal agencies directs the Columbia River Technical Advisory Committee to develop 

recommendations for research relating to steelhead management issues. 

Currently, data available to estimate historical harvest rates are quite limited and of uncertain 

quality, particularly for lower river fisheries. No catches for lower river commercial fisheries are 

reported in available databases because the sale of steelhead by non-Indians has not been 

permitted since 1975, but mortalities from drop-off and release mortalities are known to occur. 

Total catches of steelhead by sport fisheries are estimated largely through punch card data, but 

harvest estimates for A-Run or B-Run fish35 are not readily available. Mortalities are estimated 

through modeling of in-river fisheries. A limited data set is available from the July 2002 Status 

Report. Columbia River Fish Runs and Fisheries, 1938-2000 prepared by the Washington and 

Oregon Departments of Fish & Wildlife (Figure C-7). These data clearly indicate that in-river 

harvest rates for both lower and upper river fisheries have decreased substantially. 

 

34 Status Review of West Coast Steelhead. NOAA/NWFSC/NWFSC-TM27. 35 Regulations that prohibit retention of fish with intact adipose fins make it infeasible to directly estimate sport 

fishery impacts on wild steelhead. 

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ISAB 2005-4 Harvest Report 

Inriver Fishery Harvest Rates on Snake River B-Run Steelhead

0.0

0.1

0.2

0.3

0.4

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Year

InRiver Harvest Rate

Lower River Above Bonneville

Figure C-7. 1984-2000 Harvest Rates for B-Run Steelhead. 

The harvest rates depicted in Figure C-7, however, represent fishery impacts on the entire BRun, which is comprised of both hatchery and wild fish. Constraints on harvest impacts are 

expressed in terms of maximum 15% harvest rate on the wild component of the B-Run. Under 

the management plan36 for Columbia River fisheries, steelhead larger than 78 cm in length with 

adipose fins intact and which pass Bonneville Dam from July 1 through October 31 are 

considered wild B-Run fish. Data are not readily available to evaluate the effectiveness of these 

criteria in distinguishing wild B-Run steelhead from other commingled stocks of hatchery37 and 

wild steelhead. Estimated harvest rates on the estimated number of wild B-Run steelhead passing 

Bonneville Dam by the treaty “zone 6” fishery are depicted in Figure C-8. 

The quality of the available data set for wild B-Run steelhead is uncertain. At least one 

inconsistency is apparent - the number of fish passing Lower Granite Dam in 2003 was larger 

than the number passing Bonneville Dam. The reason for this discrepancy is not evident, but 

may be related to sampling. 

 

36 2005-2007 Interim Management Agreement For Upriver Chinook, Sockeye, Steelhead, Coho, and White 

Sturgeon. 37 Available CWT data are not sufficient to provide information to test the effectiveness of criteria employed for 

stock-separation. Because these criteria depend only on run timing and size, separation of hatchery and wild fish can

be problematic. The Dworshak National Fish Hatchery releases approximately 1.2 million yearling B-Run smolts 

on-station and another 1.1 million yearling B-run smolts for outplanting. Biological Opinion on Artificial 

Propagation in the Columbia River, March 29, 1999. 

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ISAB 2005-4 Harvest Report 

Wild B Index Steelhead Run at Bonneville and Treaty Zone 6 Fall 

Sesaon Harvest Rate (Rates based on Length Based Run Size)

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

1985 1990 1995 2000

Year

Number of Fish

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

Harvest Rate

Wild B Steelhead Run Size Treaty Zone 6 Fall Season Harvest Rate

 

Figure C-8. 1985-2004 Zone 6 Harvest Rates for Wild B-Run Steelhead. 

Literature Cited in Appendix C: 

Morishima, G.S. 1999. When is a Fish Not a Fish? Metrics of Exploitation for Chinook Salmon: 

Fish, e-fish, and the Prodigious Proliferation of Acronyms. Unpublished manus., 

prepared for a modeling workshop convened by the Northwest Indian Fisheries 

Commission and Washington Department of Fish & Wildlife, October 20, 1999. 

TCCHINOOK(04)-2. 2004. Catch and escapement of Chinook salmon under the Pacific Salmon 

Commission jurisdiction, 2003. June, 2004. Pacific Salmon Commission, 600-1155 

Robson St., Vancouver, BC V6E 1B5. 

TCCHINOOK(04)-4. 2004. Annual exploitation rate analysis and model calibration. December, 

2004. Pacific Salmon Commission, 600-1155 Robson St., Vancouver, BC V6E 1B5. 

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