Fish Consumption Rates 

Technical Support Document

A Review of Data and Information about Fish 

Consumption in Washington

Version 2.0

Final

January 2013

Publication No. 12-09-058
Publication and Contact Information

This report is available on the Department of Ecology’s website at 

www.ecy.wa.gov/biblio/1209058.html 

For more information contact:

Toxics Cleanup Program

P.O. Box 47600 

Olympia, WA 98504-7600 

Phone: 360-407-7170

Washington State Department of Ecology - www.ecy.wa.gov

o Headquarters, Olympia 360-407-6000

o Northwest Regional Office, Bellevue 425-649-7000

o Southwest Regional Office, Olympia 360-407-6300

o Central Regional Office, Yakima 509-575-2490

o Eastern Regional Office, Spokane 509-329-3400

If you need this document in a format for the visually impaired, call the Toxics Cleanup Program 

at 360-407-7170. Persons with hearing loss can call 711 for Washington Relay Service. Persons 

with a speech disability can call 877-833-6341.

To request information about this report in another language please contact the Department of 

Ecology Toxics Cleanup Program – Headquarters, Lacey Washington at (360) 407-7170.
Fish Consumption Rates

Technical Support Document

A Review of Data and Information

about Fish Consumption in Washington

Version 2.0

Final

Toxics Cleanup Program

Washington State Department of Ecology

Olympia, Washington
This page purposely left blank for duplicate printing.
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Table of Contents

Page

List of Tables and Figures.............................................................................................................. iii

Tables .......................................................................................................................... iii

Figures .......................................................................................................................... vi

Acronyms and Abbreviations ....................................................................................................... vii

Acknowledgments.......................................................................................................................... ix

Preface to Version 2.0.................................................................................................................... xi

Executive Summary..................................................................................................................... xiii

Chapter 1 : Introduction and Purpose .............................................................................................1

1.1 Introduction.......................................................................................................................1

1.2 Intended audience .............................................................................................................2

1.3 Purpose of this document..................................................................................................4

1.4 Document history..............................................................................................................4

1.5 Organization of this document..........................................................................................6

Chapter 2 : Washington Fish Resources and Fish-Consuming Populations...................................7

2.1 Introduction.......................................................................................................................7

2.2 Washington fish resources................................................................................................7

2.2.1 Washington’s commercial fisheries...................................................................8

2.2.2 Washington’s recreational fisheries...................................................................9

2.3 Washington fish-consuming population .........................................................................11

2.3.1 Estimated number of fish consumers in Washington ......................................12

2.3.2 Estimated number of high fish-consuming adults ...........................................14

2.3.3 Assumptions.....................................................................................................16

2.3.4 Estimated number of high fish-consuming children........................................17

2.4 High fish-consuming populations...................................................................................18

2.4.1 Washington Native American Tribes...............................................................18

2.4.2 Asian and Pacific Islanders..............................................................................19

2.4.3 Subsistence and recreational fishers ................................................................19

2.5 Sources of Fish Consumed..............................................................................................20

2.6 Summary.........................................................................................................................20

Chapter 3 : Methodology for Assessing Fish Consumption Rate Information.............................23

3.1 Introduction.....................................................................................................................23

3.2 Surveys and other approaches used to estimate fish consumption .................................24

3.2.1 Creel surveys....................................................................................................25

3.2.2 Personal interviews..........................................................................................27

3.2.3 Diary surveys...................................................................................................28

3.2.4 Telephone surveys ...........................................................................................28

3.2.5 Recall mail surveys..........................................................................................29

3.3 Survey selection criteria..................................................................................................29
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3.4 Evaluating survey vehicles .............................................................................................31

3.4.1 General survey design......................................................................................31

3.4.2 Survey questions..............................................................................................32

3.4.3 Population surveyed.........................................................................................33

3.4.4 Description of water body................................................................................33

3.4.5 Survey results...................................................................................................33

3.4.6 Factors to consider...........................................................................................33

3.5 Measures of technical defensibility ................................................................................34

3.6 Custody of fish dietary survey data ................................................................................37

Chapter 4 : Fish Consumption Survey Data that Apply to Washington Fish Consumers............39

4.1 Introduction.....................................................................................................................39

4.2 General population data ..................................................................................................40

4.2.1 Continuing Survey of Food Intakes by Individuals.........................................40

4.2.2 National Health and Nutrition Examination Survey, 2003 to 2006.................42

4.3 Pacific Northwest Native American fish consumption data ...........................................46

4.3.1 Columbia River Inter-Tribal Fish Commission survey: the Umatilla, 

Nez Perce, Yakama, and Warm Springs Tribes of the Columbia River 

Basin ................................................................................................................47

4.3.2 Tulalip and Squaxin Island Tribes of the Puget Sound Region .......................53

4.3.3 Suquamish Tribe ..............................................................................................59

4.4 Asian and Pacific Islanders.............................................................................................64

4.4.1 Reanalysis by EPA Region 10 .........................................................................67

4.5 Recreational fishers.........................................................................................................70

4.6 Additional fish consumption rate information evaluated by Ecology ............................71

4.7 Key Findings...................................................................................................................74

Chapter 5 : Sources of Uncertainty and Variability......................................................................79

5.1 Survey methodology .......................................................................................................80

5.1.1 Differences due to survey design, terminology, and definitions .....................81

5.1.2 Types of data and methods of collection .........................................................81

5.1.3 Cooked and uncooked tissue weights..............................................................82

5.1.4 Variability within a population ........................................................................82

5.1.5 Data analysis and statistical considerations.....................................................82

5.1.6 Target populations and characteristics of populations.....................................84

5.2 Geographic differences...................................................................................................85

5.2.1 Variation and uncertainty associated with regional differences ......................85

5.2.2 Uncertainty associated with extrapolating survey results to different 

population groups and different locations........................................................86

5.2.3 Availability of finfish and shellfish .................................................................87

5.3 Temporal uncertainty and variability..............................................................................88

5.3.1 Using short-term data to estimate long-term exposure ....................................88

5.3.2 Temporal factors biasing estimates of fish consumption.................................89

5.3.3 Issues using currently suppressed fish consumption data to predict 

future fish consumption ...................................................................................90

5.4 Uncertainty in Pacific Northwest fish-consuming populations......................................91
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Chapter 6 : Using Scientific Data to Support Regulatory Decisions............................................93

6.1 Population groups ...........................................................................................................94

6.2 Individual variability in fish consumption rates .............................................................95

6.3 Geographic variability ....................................................................................................97

6.4 Salmon 98

6.5 Sources of finfish/shellfish .............................................................................................99

6.6 Consumer vs. per capita................................................................................................100

6.7 Other exposure variables...............................................................................................101

6.8 Acceptable risk levels...................................................................................................103

6.9 Summary.......................................................................................................................103

Appendices.................................................................................................................................. A-1

Appendix A Information on Bioaccumulation, Fish Consumption by Children, and 

Species Consumed ....................................................................................................... A-1

Appendix B Additional Fish Consumption Studies...........................................................B-1

Appendix C The Question of Salmon ................................................................................C-1

Appendix D Glossary ........................................................................................................ D-1

Appendix E References......................................................................................................E-1

List of Tables and Figures

Tables 

Page

Table 1. Summary of Fish Consumption Data, All Finfish and Shellfish (g/day)................ xvi

Table 2. Different Metrics Used to Describe Fish Consumption Rates....................................3

Table 3. Commercial Fish Landings from Washington Non-treaty Fisheries in 2006 .............9

Table 4. Number of Recreational Finfish Caught in Washington Waters in 2006 by 

Species and Region...................................................................................................10

Table 5. Pounds of Shellfish Taken Recreationally From Washington Waters in 

2006, by Species and Region ....................................................................................11

Table 6. Estimated Washington Fish Consumers Based on Washington DOH Survey 

Data ...........................................................................................................................14

Table 7. Estimated Number of Fish Consumers among the General Washington 

Adult Population .......................................................................................................17

Table 8. Estimated Number of Child Fish Consumers among the General Washington 

Population .................................................................................................................18

Table 9. Strengths and Weaknesses of Creel Surveys............................................................26

Table 10. Strengths and Weaknesses of Personal Interviews...................................................27

Table 11. Strengths and Weaknesses of the Diary Method ......................................................28
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Table 12. Strengths and Weaknesses of Telephone Surveys....................................................28

Table 13. Strengths and Weaknesses of Recall Mail Surveys..................................................29

Table 14. Comparison of Five Consumption Survey Methodologies Using EPA’s 

Selection Criteria ......................................................................................................30

Table 15. Survey Design Evaluation Criteria ...........................................................................31

Table 16. Measures of Technical Defensibility ........................................................................36

Table 17. General Population: Adult Respondents, Consumers Only, Based on CSFII 

1994 to 1996 .............................................................................................................42

Table 18. General Population: Adult Respondents, Consumers Only, Based on 

NHANES 2003–2006, Using Standard Statistical Survey Methodology.................43

Table 19. General Population: Adult Respondents, Consumers Only, Based on 

NHANES 2003–2006, Using NCI Statistical Survey Methodology ........................44

Table 20. Technical Defensibility of National (General Population) Fish Dietary 

Information ...............................................................................................................45

Table 21. CRITFC Adult Fish Consumption Rates by Species Group and Source, 

Consumers Only........................................................................................................48

Table 22. Columbia River Inter-Tribal Fish Commission Consumption Survey .....................50

Table 23. Tulalip Tribal Adult Fish Consumption Rates by Species Group and Source .........55

Table 24. Squaxin Island Tribal Adult Fish Consumption Rates by Species Group and 

Source .......................................................................................................................56

Table 25. Fish Consumption Survey of the Tulalip and Squaxin Island Tribes of the 

Puget Sound Region..................................................................................................58

Table 26. Suquamish Tribal Adult Fish Consumption Rates by Species Group and 

Source .......................................................................................................................61

Table 27. Fish Consumption Survey of the Suquamish Indian Tribe of the Port 

Madison Indian Reservation, Puget Sound Region ..................................................62

Table 28. Adult Respondents to the Asian and Pacific Islander Survey...................................65

Table 29. Asian and Pacific Islander Seafood Consumption Study .........................................66

Table 30. API Adult Seafood Consumption Rates by Species Group and Source ...................69

Table 31. API Seafood Consumption Rates Adjusted for Cooking Loss.................................69

Table 32. Fish Consumption Information Relevant to Washington and Considered by 

Ecology .....................................................................................................................72

Table 33. Summary of Fish Consumption Rates from Studies Meeting the Measures of 

Technical Defensibility, All Finfish and Shellfish (g/day).......................................75

Table 34. Percent of Tribal Fish Consumption Rate (All Sources) that is Locally 

Harvested ..................................................................................................................77
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Table 35. Percent of Tribal Anadromous Fish Consumption Rate (All Sources) that is 

Locally Harvested .....................................................................................................77

Table 36. Percent of Tribal Shellfish Consumption (All Sources) that is Locally 

Harvested ..................................................................................................................78

Table 37. Summary of Fish Consumption Rates, All Finfish and Shellfish.............................95

Table A-1. Fish Consumption Rates of Native American Children 5 or 6 Years of Age 

or Less.................................................................................................................... A-4

Table A-2. Tribal Fish Consumption Rates ............................................................................. A-5

Table A-3. Fish Consumption Rate Data for Asian and Pacific Islanders............................... A-5

Table A-4. EPA Data on Children’s Finfish and Shellfish Consumption Rates for the 

U.S. General Population ........................................................................................ A-6

Table A-5. Seafood Consumed by Adult Members of the Tulalip Tribes............................... A-6

Table A-6. Seafood Consumed by Adult Members of the Suquamish Tribe .......................... A-7

Table A-7. Seafood Consumed by Adult Asian-Pacific Islanders (API)................................. A-7

Table B-1. Fish Consumption Rates for Japanese and Korean Washington Populations ........B-3

Table B-2. Percent of Households Using Subsistence Resources during 1997–1998..............B-5

Table B-3. Makah Indian Tribe Per Capita Harvest and Consumption of Subsistence 

Fish (pounds) ..........................................................................................................B-6

Table B-4. Summary of Fish Type Consumed, Percentage of Population that Consumed 

Fish Type, and Percentage Harvest Source from Local Areas by Colville 

Reservation Residents.............................................................................................B-9

Table B-5. Cumulative Risks to Swinomish Tribal Finfish- and Shellfish-Consuming 

Populations............................................................................................................B-14

Table C-1. Pacific Salmon Life Cycle ......................................................................................C-5

Table C-2. Average PCB Concentrations for Coho and Chinook Salmon from In-River 

and Marine Locations, Puget Sound (μg/kg)..........................................................C-6

Table C-3. Status of Washington Salmon Stocks as of 1992....................................................C-9

Table C-4. Status of Puget Sound Salmon Stock as of 1992 ....................................................C-9

Table C-5. 2002 By-Species Summary Update of WDFW’s Salmonid Stock Inventory 

(SaSI) Status for Washington State Salmon and Steelhead Stock 

Classifications.......................................................................................................C-10

Table C-6. Life Histories of Pacific Coast Salmonids............................................................C-18

Table C-7. Biological Variability in Life Histories of Pacific Salmonids..............................C-19

Table C-8. 2001–2002 Freshwater Salmon Sport Catch for Puget Sound River Systems .....C-20

Table C-9. 2001–2002 Sport Salmon Catch for East Juan de Fuca (Port Angeles Areas) .....C-20

Table C-10. 2002–2003 Freshwater Salmon Sport Catch for Puget Sound River Systems .....C-20
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Table C-11. 2002–2003 Sport Salmon Catch for East Juan de Fuca (Port Angeles Areas) .....C-20

Table C-12. Salmonid Stock Inventory for the Port Angeles Harbor and Adjacent Areas ......C-21

Table C-13. Salmonid Stock Inventory for The Port Angeles Harbor and Adjacent Areas.....C-22

Table C-14. Salmonid Stock Inventory for the Port Angeles Harbor and Adjacent Areas ......C-22

Figures 

Page

Figure 1. General Population Adult Fish Consumption Rates, Consumers Only, 

NHANES 2003–2006, Using Standard Statistical Survey Methodology.................44

Figure 2. General Population Adult Fish Consumption Rates, Consumers Only, 

NHANES 2003–2006, Using NCI Statistical Survey Methodology ........................45

Figure 3. CRITFC Adult Fish Consumption Rates, Harvested from All Sources ...................49

Figure 4. CRITFC Adult Fish Consumption Rates, Harvested from Columbia River 

Basin .........................................................................................................................49

Figure 5. Tulalip Tribal Adult Fish Consumption Rates, Harvested from All Sources...........55

Figure 6. Tulalip Tribal Adult Fish Consumption Rates, Harvested from Puget Sound .........56

Figure 7. Squaxin Island Tribal Adult Fish Consumption Rates, Harvested from All 

Sources......................................................................................................................57

Figure 8. Squaxin Island Tribal Adult Fish Consumption Rates, Harvested from Puget 

Sound ........................................................................................................................57

Figure 9. Suquamish Tribal Adult Fish Consumption Rates, Harvested from All 

Sources......................................................................................................................61

Figure 10. Suquamish Tribal Adult Fish Consumption Rates, Harvested from Puget 

Sound ........................................................................................................................62

Figure 11. API Adult Fish Consumption Rates, Harvested from King County (KC) and 

Other Sources, Adjusted for Cooking Loss ..............................................................70

Figure 12. Regional-specific Adult Fish Consumption Rates, Harvested from All 

Sources......................................................................................................................76

Figure 13. Regional-specific Adult Fish Consumption Rates, Harvested from Local 

Sources......................................................................................................................76

Figure 14. Density function for a positively skewed lognormal distribution.............................84

Figure 15. MTCA Surface Water Cleanup Standards Equation (Non-Carcinogenic 

Hazards)..................................................................................................................102

Figure 16. MTCA Surface Water Cleanup Standards Equation (Carcinogenic Risk).............102
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Acronyms and Abbreviations

API Asian and Pacific Islander

ATSDR Agency for Toxic Substances and Disease Registry

BAF bioaccumulation factor

BCF bioconcentration factor

bw body weight

BRFSS Behavioral Risk Factor Surveillance System

CDC Centers for Disease Control and Prevention

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CRITFC Columbia River Inter-Tribal Fish Commission

CSFII Continuing Survey of Food Intakes by Individuals

CWA Clean Water Act

DDT dichlorodiphenyltrichloroethane

DOH Washington State Department of Health

Ecology Washington State Department of Ecology

EPA U.S. Environmental Protection Agency

g/day grams per day

g/kg grams per kilogram

IHS Indian Health Service

μg/kg micrograms per kilogram

μg/L micrograms per liter

μg/mg micrograms per milligram

MTCA Model Toxics Control Act

NCI National Cancer Institute

NHANES National Health and Nutrition Examination Survey

NOAA National Oceanic and Atmospheric Administration

Oregon DEQ Oregon Department of Environmental Quality

OFM Office of Financial Management

PAH polycyclic aromatic hydrocarbon

PBDE polybrominated diphenyl ether

PBT persistent bioaccumulative toxic

PCB polychlorinated biphenyl

POP persistent organic pollutant

QA/QC quality assurance/quality control

RCRA Resource Conservation and Recovery Act

RME reasonable maximum exposure

SaSI Salmonid Stock Inventory

SMS Sediment Management Standards

U.S. United States
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USDA U.S. Department of Agriculture

WAC Washington Administrative Code

WDF Washington Department of Fisheries

WDFW Washington Department of Fish and Wildlife

WRIA Water Resource Inventory Area
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Acknowledgments

The Washington State Department of Ecology wishes to thank the many people who have 

participated in the ongoing dialogue on fish consumption rates. There have been many 

conversations through the years, with a great many people providing insight and input, 

answering questions, reviewing draft documents, and clarifying various issues. In particular, 

Ecology wishes to acknowledge the following people. Persons listed here provided constructive 

input and feedback; they were not, however, asked to endorse the final product, and did not see 

the final report before its release. 

University of Washington

 Dr. William (Bill) Daniell, Associate Professor, Environmental and Occupational Health 

Sciences

 Dr. Elaine Faustman, Professor, Environmental Health

 Dr. William (Bill) Griffith, Principal Research Scientist and Director of the Risk 

Assessment Core of the Institute for Risk Analysis and Risk Communication

 Alison Scherer, Research Scientist, Environmental and Occupational Health Sciences

 Anna Schmidt, Graduate Student, Environmental and Occupational Health Sciences

 Dr. Thomas M. Burbacher, Professor, Environmental Health

 Dr. Vincent F. Gallucci, Professor, Aquatic and Fishery Sciences

 Verna Blackhurst, School of Aquatic and Fishery Sciences

Seattle University School of Law

 Catherine A. O’Neill, Professor of Law 

 Doug Nash, Professor of Law and member of Nez Perce Tribe

Washington State Department of Health (DOH)

 Maria C. Gardipee

 Dr. Joan Hardy

 David McBride

 Dr. Jim W. White

Selected Tribal Representatives

 Larry Dunn, Lower Elwha Klallam Tribe

 Don Hurst and Patti Bailey, Confederated Tribes of the Colville Reservation

 Fran Wilshusen, Northwest Indian Fisheries Commission

 Denice Taylor, Suquamish Tribe
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 Dianne C. Barton and Aja DeCoteau, Columbia River Inter-Tribal Fish Commission 

(CRITFC)

Washington State Office of Financial Management

 Yi Zhao, Chief Demographer

Washington Department of Fish and Wildlife

 James E. West

National Oceanic and Atmospheric Administration

 Thomas Hooper

 Sandra O’Neill

U.S. Environmental Protection Agency, Headquarters, Washington, D.C.

 Dr. Jacqueline Moya

 David J. Miller

 David Hardy

 Bayazid Sarkar

 Aaron Niman

U.S. Environmental Protection Agency, Region 10, Seattle

 Lon Kissinger, Senior Toxicologist

Selected members of the Human Health Focus Group, Oregon Dept of Environmental Quality

 Dr. Patricia Cirone (Affiliate Professor, University of Washington)

 Dr. Bruce Hope, Senior Toxicologist

 DOH personnel identified above

Statisticians

 Dr. Nayak Polissar, The Mountain-Whisper-Light Statistics

 Dr. Moni Blazej Neradilek, The Mountain-Whisper-Light Statistics

 Dr. Sasha Aravkin, The Mountain-Whisper-Light Statistics

 Dr. Shiquan Liao, King County
Preface to Version 2.0

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Preface to Version 2.0

Washington’s marine and fresh waters are home to rich stocks of finfish and shellfish, and these 

resources are vital to the well-being of the peoples of our state.1Several years ago the 

Washington State Department of Ecology (Ecology) began work reviewing fish consumption 

rates as part of updating environmental cleanup regulations, and subsequently produced a draft 

Technical Support Document. The evaluations presented in that document followed similar 

evaluations done in Oregon. Ecology received several hundred comments on the draft document 

and has made revisions based on input received. Additional analyses were performed and 

supplemental information was gathered to support preparation of this revised version.

Regulatory context plays a role in this topic, and Ecology will be addressing both the scientific 

and policy questions associated with fish consumption rates. This Technical Support Document, 

however, does not address the policy questions. It focuses quite specifically on the issue of how 

much and what types of fish are consumed by the people of Washington, and what data are 

available about fish consumption rates.

It is appropriate and necessary to review and, if needed, update exposure parameters used in 

various regulatory contexts, and this document is offered as one part of the effort to consider fish 

consumption rates. Readers may notice that this document has evolved. Ecology produced the 

Fish Consumption Rates Technical Support Document: A Review of Data and Information about 

Fish Consumption in Washington, Version 1.0 to support dialogue related to updating the default 

fish consumption rates used in Washington environmental regulations. At that time, Ecology was 

focused on updating the Sediment Management Standards, with updates to water quality 

standards to follow at a later time. It was a draft document that posed several questions and was 

distributed for public review and input in October 2011. Although scheduled to end December 

31, 2011, the comment period was extended until January 18, 2012.2

In Version 1.0 of the Technical Support Document, Ecology collected data about fish consumers 

in Washington and looked at national data about fish consumption in the United States. We 

reviewed this information as a first step in addressing how to establish a fish consumption rate 

for use in Washington. Ecology then considered how to systematically and scientifically 

determine a default rate appropriate for use in a regulatory context. Multiple questions arose, 

including: How should the data be combined in a statistically correct manner? Is it appropriate to 

establish a single default rate for use in multiple settings? How should salmon be included in the 

default fish consumption rate?

 

1

In most places in this document, unless noted otherwise, fish refers to both finfish and shellfish.

2 Due to a winter storm that caused statewide power outages during that week, Ecology accepted all late comments.
Preface to Version 2.0

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Ecology received over 300 comments on Version 1.0 of the Technical Support Document. 

Comments were posted on the Ecology website in the order in which they were received. 

Ecology announced that a response to comments would be prepared. 

In order to respond to comments and to update the document based on public input, Ecology 

performed a number of additional analyses. The additional work in response to comments falls 

generally into the following categories:

 Technical analyses to more accurately characterize fish-consuming populations, 

including statistical review of data and methodologies.

 Research of relevant supporting information (for example, regarding recreational fish 

consumption, health benefits and risks from eating finfish and shellfish, and life strategies 

for different fish species).

Purpose

The purpose of this Technical Support Document (Version 2.0) is to compile and evaluate 

available information on fish consumption in Washington State. It is a technical document, and is 

not designed to resolve policy issues associated with using that information to make regulatory 

decisions. Those issues will be dealt with in separate rulemaking documents and processes.

However, in order to assist readers, this document does provide a certain amount of context and 

identifies some of the policy questions that are relevant to the topic of fish consumption rates. 

This document is narrower in scope than Version 1.0 of the Technical Support Document 

(distributed in October 2011). At that time, Ecology planned to adopt a default fish consumption 

rate in the Sediment Management Standards (SMS) rule. One purpose of the Technical Support 

Document (Version 1.0) was to identify a recommended range of fish consumption rates for 

consideration in the SMS rule revision process. Since that time, Ecology has decided not to 

propose a default fish consumption rate in the SMS rule. Instead Ecology is proposing to use a 

reasonable maximum exposure as the sediment cleanup standard for protecting fish consumers. 

Ecology is also beginning the process to revise the Water Quality Standards for Surface Waters 

and adopt human health criteria. 

Instead of identifying a fish consumption rate appropriate for use in a particular regulatory 

context, this document compiles relevant data and information. Ecology acknowledges the

complexity of this topic and offers this Technical Support Document to provide a thorough, 

rigorous, and comprehensive review of the available technical information about fish and fish 

consumers in Washington.
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Executive Summary

Problem statement

Washington’s aquatic resources provide tremendous benefit to the people of the state. Large 

quantities of finfish and shellfish are caught each year, both recreationally and commercially, 

and many residents eat seafood harvested from our waters. In addition, tribal populations enjoy 

treaty fishing rights, and harvesting and eating seafood plays a significant role in their cultures. 

Finfish and shellfish are important parts of a healthy diet.

Polychlorinated biphenyls (PCBs), dioxins, mercury, and other persistent chemicals can 

accumulate in fish tissue and harm the health of people who consume fish. Those who may be 

particularly vulnerable include adults who eat large amounts of finfish or shellfish, as well as 

children and other sensitive populations. Current fish consumption rates used by Ecology to 

make regulatory decisions are not consistent with data about fish consumption by Washington 

populations for which fish consumption survey information is available.

3

Ecology currently identifies two separate default fish consumption rates that have been used to 

establish regulatory requirements: 

 Washington’s Model Toxics Control Act (MTCA) Cleanup Regulation includes a default 

fish consumption rate of 54 grams (1.9 ounces) per day. This value was established in 

1991. It is based on information from a survey of Washington recreational anglers in 

Commencement Bay (Pierce et al., 1981). 

 Washington is covered under a federal regulation – the National Toxics Rule. 

Washington’s Water Quality Standards for Surface Waters currently rely on the 1992 

National Toxics Rule (57 Fed. Reg. 60848-60923 codified at 40 CFR 131.36), which

includes Water Quality Standards for human health protection based on a fish 

consumption rate of 6.5 grams (0.22 ounce) per day. 

There have been many scientific and regulatory developments related to fish consumption rates 

over the past 20 years. The review of Washington fish consumption in this Technical Support 

Document is offered to provide data and information pertinent to ongoing public dialogue 

concerning regulatory issues. This report reviews recent scientific data, noting the uncertainty and 

variability associated with those data.

 

3 Ecology has the ability to make site-specific decisions and use site-specific information, including fish consumption rates protective of tribal 

populations.
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The aquatic environment challenge

Many different species of finfish and shellfish are harvested from Washington waters. Each 

species has a unique life history and preferred habitat. Some finfish and shellfish are exposed to 

contaminants, but determining how much or where that exposure occurs is difficult. In an aquatic 

environment, contaminants move between water and sediment and from one location to another.

In addition, the various salmon species, like other anadromous fish, migrate between river and 

open ocean environments, spending only a portion of their life cycle near shore. 

The issues surrounding salmon life history are particularly complex. Most salmon leave

freshwater streams when they are juveniles, only a couple of inches long, and spend varying 

amounts of time in coastal waters. Salmon spend most of their life cycle in the open ocean, and 

return to Washington waters at the end of their life cycle. Salmon are the most frequently 

consumed fish in Washington, but how to account for the complexity they present when 

considering questions related to water and sediment quality is a challenge. This document does 

not resolve these questions. Instead it offers information that will be useful as readers think 

through various options. 

Washington fish resources

A large variety of fish and shellfish are available for harvesting in Washington, including more 

than 50 species of edible freshwater fish and almost as many in marine waters (WDFW, 2010). 

Commercial fish landings from Washington non-treaty fisheries totaled over 109 million pounds 

of finfish and shellfish in 2006, including over 25 million pounds of shellfish and over 11 million 

pounds of salmon. 

Recreationally caught finfish in Washington include albacore, bottomfish, Pacific halibut, 

salmon, steelhead, and sturgeon, with the 2006 catch totaling over 840,000 fish. Over 113,000 

pounds of shellfish were collected from Washington waters in 2006, primarily Dungeness crab 

and razor clams. 

Washington fish consumers 

Ecology estimates that between 1.4 and 3.8 million Washington adults and 290,000 children 

consume some amount of fish as part of their diet.

4

 

4 The term fish in this document may refer to finfish or to both finfish and shellfish. The term fish consumption usually refers to consumption of 

both finfish and shellfish. The intent should be clear from the context; where appropriate the distinction is noted.
Executive Summary

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Recreational fishers may consume more fish than the general Washington population. Some 

population groups consume especially large amounts of finfish and shellfish as part of 

traditionally influenced diets. These include Native Americans and Asian and Pacific Islanders. 

Fish consumption surveys

Information about fish consumption can be collected in a variety of ways. This document 

describes the different methodologies used to collect information about fish consumption. To 

identify robust and defensible surveys relevant to Washington, Ecology reviewed survey 

methodologies and survey results by considering measures of technical defensibility.

Ecology reviewed general population data from national surveys. Statistical methodology used 

by the National Cancer Institute (NCI) was applied to the national survey data to better estimate 

long-term consumption rates using short-term dietary records. 

Ecology reviewed available information on fish consumption in Washington. Certain dietary 

recall surveys are identified as well-designed and well-conducted. The following studies meet 

measures of technical defensibility and contain data directly applicable to Washington 

population groups:

 A Fish Consumption Survey of the Umatilla, Nez Perce, Yakama, and Warm Springs 

Tribes of the Columbia River Basin (CRITFC, 1994).

 A Fish Consumption Survey of the Tulalip and Squaxin Island Tribes of the Puget Sound 

Region (Toy et al., 1996).

 Fish Consumption Survey of the Suquamish Indian Tribe of the Port Madison Indian 

Reservations, Puget Sound Region (The Suquamish Tribe, 2000).

The Asian and Pacific Islander Seafood Consumption Study (Sechena et al., 1999, including 

EPA’s 2005 re-evaluation) is a well-designed and conducted study, but it represents a very small 

sample of each of the Asian and Pacific Islander populations surveyed, and statewide populations 

may differ. 

Data on recreational fishing provide another piece of information about fish consumers in 

Washington. However, this information is collected from creel surveys and is therefore less 

useful than dietary recall surveys for estimating consumption rates for a population. (The data 

are included with the table below for convenience only.)

Survey information for the general population, Pacific Northwest populations, and recreational 

fishers is summarized in Table 1.
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In response to public review comments received by Ecology 

on Version 1.0 of this Technical Support Document, 

supplementary information (provided as separate Technical 

Issue Papers) has been prepared to provide additional detail 

on topics of specific relevance to the evaluation of fish 

consumption rates. These topics include:

 Estimating annual fish consumption rates using 

data from short-term surveys.

 Recreational fish consumption rates.

 Health benefits and risks of consuming finfish and 

shellfish.

 Chemical contaminants in dietary protein sources.

 Salmon life history and body burdens.

These Technical Issue Papers are provided in Ecology, 2012 

(Supplemental Information to Support the Fish Consumption 

Rates Technical Support Document).

Table 1. Summary of Fish Consumption Data, All Finfish and Shellfish (g/day)

Population Source of Fish

Number of 

Adults 

Surveyed

Mean

Percentiles

50th 90th 95th

General population

(consumers only)

All sources: EPA method 2,853 56 38 128 168

All sources: NCI method 6,465 19 13 43 57

Columbia River Tribes All sources 464 63 41 130 194

Columbia River – 56 36 114 171

Tulalip Tribes All sources 73 82 45 193 268

Puget Sound 71 60 30 139 237

Squaxin Island Tribe All sources 117 84 45 206 280

Puget Sound – 56 30 139 189

Suquamish Tribe All sources 92 214 132 489 797

Puget Sound 91 165 58 397 767

Recreational Fishers

(compilation of multiple studies) 

Marine waters, WA State – 11–53 1.0–21 13–246

Freshwater, WA State – 6.0–22 – 42–67

Sources: Adapted from Polissar et al., 2012, Table E-1. Data for recreational fishers is from Table 3, Technical Issue Paper: Recreational Fish 

Consumption Rates (Ecology, 2012). General population data are for consumers only, as opposed to per capita. See Chapters 4 and 6. 

Key technical findings

Key findings of this Technical Support 

Document include the following:

 Significant numbers of people in 

Washington consume finfish and 

shellfish. Ecology estimates that 

between 1.4 and 3.8 million adults 

in Washington eat finfish or 

shellfish at least occasionally.

 No survey data currently exist about 

fish consumption rates specific to 

the general population in 

Washington. Statistical evaluation of national fish consumption data may provide useful 

information about fish consumption among the general population. For estimates based 

on national data, the methodology developed by the National Cancer Institute provides 

improved accuracy for episodically consumed foods. 

 Regional-specific fish dietary surveys provide technically defensible information about 

high fish-consuming populations in the Pacific Northwest. 
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Supporting information

In addition to the key findings, this document includes information that allows a more 

comprehensive understanding of fish consumption patterns in Washington. This information,

taken collectively, provides multiple lines of evidence about fish consumption in Washington. 

For example, water body-specific evaluations, predominantly creel surveys, do provide 

additional information about fish consumption. 

In addition, this document looks at identifying species that are locally harvested5and consumed.

 About 68 percent of total fish consumed by the Squaxin Island tribal population is locally 

harvested. The percentage of total fish consumed that is locally harvested is somewhat 

higher for the other tribal populations surveyed: approximately 88 percent for the 

Columbia River Tribes, 72 to 88 percent for the Tulalip Tribes, and 81 to 96 percent for 

the Suquamish tribe. 

 Where possible, data on types of fish consumed and where the fish were obtained are 

provided, allowing a regional look at fish consumption patterns.

 About 62 percent of shellfish consumed by Squaxin Island tribal populations are locally 

harvested. The percentage of shellfish that is locally harvested is somewhat higher for the 

Suquamish Tribe (81 percent), and highest for the Tulalip Tribes (98 percent or higher). 

 

5 The term locally harvested is used to identify the source of fish. It is used to distinguish fish harvested locally from fish purchased and coming 

from unknown and potentially non-local (out of state) sources.
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Chapter 1: Introduction and Purpose

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Chapter 1: Introduction and Purpose

1.1 Introduction

This report addresses fish consumption among Washington fish consumers, including the general 

population, tribal populations, and other groups, such as Asian and Pacific Islanders and 

recreational anglers, who are known to eat large amounts of fish.6 

The Washington State Department of Ecology (Ecology) currently recognizes two separate 

default fish consumption rates used to establish regulatory requirements: 

 Washington’s Model Toxics Control Act (MTCA) Cleanup Regulation includes a default 

fish consumption rate of 54 grams (1.9 ounces) per day. This value was established in 

1991. It is based on information from a survey of Washington recreational anglers in 

Commencement Bay (Pierce et al., 1981). 

 Washington is covered under a federal regulation – the National Toxics Rule. 

Washington’s Water Quality Standards for Surface Waters currently rely on the 1992 

National Toxics Rule (57 Fed. Reg. 60848-60923 codified at 40 CFR 131.36), which 

includes Water Quality Standards for human health protection based on a fish consumption 

rate of 6.5 grams (0.22 ounce) per day.

7

This value is based on technical evaluations 

completed by the U.S. Environmental Protection Agency (EPA) in the mid-1980s. It 

represents the low estimate of national average per capita consumption of fish and shellfish 

from estuarine and fresh waters (45 Fed. Reg. 79348; U.S. EPA, 1980).

8

The methods used to develop these two rates included a number of differing assumptions about 

exposures. The MTCA fish consumption rate of 54 grams per day (g/day) is a recreational rate 

based on a creel survey from Commencement Bay. The Water Quality Standards default fish 

consumption rate of 6.5 g/day is the average per capita consumption rate of all (contaminated and 

non-contaminated) freshwater and estuarine fish for the U.S. population (57 Fed. Reg. 60848-

60923 codified at 40 CFR 131.36). This average includes people who never eat fish.

To estimate the average per capita intake of a pollutant due to consumption of contaminated fish 

and shellfish, the results of an early 1980s seafood dietary survey (U.S. EPA, 1980) were 

analyzed to calculate the average consumption of freshwater and estuarine fish and shellfish (45 

 

6 For the purposes of this report, fish consumers include all people in Washington who eat finfish or shellfish. While there is variability among 

how much fish is consumed by—both within and among—various population groups, some people never include fish in their diets. These 

people are considered non-consumers.

7 The 6.5 grams per day contaminated fish consumption value is equivalent to the average per-capita consumption rate of all (contaminated 

and non-contaminated) freshwater and estuarine fish for the U.S. population (57 Fed. Reg. 60863).

8 Moderate and high average fish consumption estimates for the U.S. national population were based on the consumption of fish and shellfish 

from fresh, estuarine, and marine waters (U.S. EPA, 1989a). 
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Fed. Reg. 79348). In the absence of estimates of fish dietary information from local fishconsuming populations, an EPA companion guidance document to the National Toxics Rule 

proposed the following average consumption rates: 

 6.5 g/day to represent a low estimate of average consumption of fish and shellfish from 

estuarine and fresh waters by the U.S. population.

 20 g/day to represent a moderate estimate of the average consumption of fish and 

shellfish from marine, estuarine, and fresh waters by the U.S. population.

 165 g/day to represent a high estimate of the average consumption of fish and shellfish 

from marine, estuarine, and fresh waters by the 99.9th percentile of the U.S. population.

In contrast to the low average estimate, the moderate and high average fish consumption estimates 

for the U.S. population is based on the consumption of fish and shellfish not only from fresh and 

estuarine waters but also from marine waters (U.S. EPA, 1989a, page 58 and Table 7, page 71).

There have been many scientific and regulatory developments related to fish consumption rates 

over the past 20 years. These include:

 Acquisition of recent scientific data on finfish and shellfish consumption rates for 

different population groups.

 Updated approaches used by other state and federal agencies.

 Analysis of uncertainty and variability in finfish and shellfish consumption rates for 

different population groups and individuals within those groups.

 Analysis of current and potential future exposures resulting from finfish and shellfish 

consumption.

 Revision of state laws and policies, including MTCA and the Water Pollution Control Act.

 Assertion of tribal fishing rights by tribes.

1.2 Intended audience

Ecology will use this document to engage multiple audiences in discussions on issues related to 

fish consumption rates.9This report is meant to facilitate discussions with interested parties and 

persons throughout Washington.

To facilitate these discussions, it is important to understand the different ways we express fish 

consumption rates in this Technical Support Document. In general, a fish consumption rate is 

presented as grams of fish consumed per day (g/day). For many readers, it is easier to understand 

a fish consumption rate expressed in ounces per day, or number of 8-ounce meals per week. (An 

 

9 The term fish includes all types of finfish and shellfish. When discussing the species that are consumed, fish are categorized by species 

groupings.
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8-ounce meal corresponds to approximately 227 grams.) Another way to express fish 

consumption is in terms of the frequency of an 8-ounce meal (e.g., once per month, three times 

per week), or as total pounds of fish per year. Table 2 summarizes the different metrics that are 

used to describe fish consumption rates.

Table 2. Different Metrics Used to Describe Fish Consumption Rates

Consumption Rate 

Metric Examples of Consumption Rates For Each Metric

Grams per day 6.5 17.5 50 100 260 500 620

Ounces per day 0.23 0.62 1.8 3.5 10 18 22

Number of 8-ounce 

meals per week

0.2 0.5 1.5 3 8 15 17

Frequency of 

8-ounce meals

< one 

8-ounce 

meal per 

month

Two 

8-ounce 

meals per 

month

One to two 8-

ounce meals 

per week

Three 

8-ounce 

meals per 

week

Every day 

or 1⁄2 pound 

per day

Twice per 

day or 

1 pound 

per day

1 pound per 

day plus 

other forms 

and uses

Pounds per year 5 15 40 80 200 400 500

Source: Adapted from Swinomish Tribe, 2006, Table 30.

In the absence of population-specific fish dietary information, the U.S. EPA suggest using a default value of 8 ounces (227 grams) as an 

average meal size for the general adult population (72-kilogram person) for exposure assessments and fish advisories (U.S. EPA, 2000d).

 

 

Fish portion sizes (6.5, 54, 175, and 243 grams)
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1.3 Purpose of this document

The purpose of this Technical Support Document (Version 2.0) is to compile and evaluate 

existing data on fish consumption in Washington State. It is a technical document, and is not 

designed to resolve policy issues associated with using that information to make regulatory 

decisions. Those issues will be dealt with in separate rulemaking documents and processes.

This Technical Support Document provides useful background information for discussions related 

to finfish and shellfish consumption rates. The primary question addressed in this document is:

 What is currently known about fish consumption habits and rates for people in Washington? 

Specifically, what types of data are available, how much fish do people in various population 

groups eat, what kinds of fish do they eat, and where do they obtain the fish? 

Ecology recognizes that many other considerations factor into calculating protective standards, 

including acceptable risk levels and exposure parameters (such as exposure duration). These 

considerations may be relevant to various regulatory discussions. This particular document, 

however, focuses primarily on technical information related to fish consumption rates. 

1.4 Document history

Ecology distributed the Fish Consumption Rates Technical Support Document, Version 1.0, for 

public review in September 2011. The document was prepared to support discussion on whether 

and how to revise the fish consumption rates in the Sediment Management Standards (SMS) rule. 

Ecology held several public workshops to discuss the draft report and regulatory implications.

Ecology received several hundred written comments on the draft report. Ecology has reviewed 

those comments and prepared written responses that are compiled in a separate document. As 

part of that review, Ecology also performed additional technical analyses to address several 

issues raised during the public comment period.

Ecology has considered the comments and analyses when revising this Technical Support 

Document. Significant revisions include the following:

 General population studies. Several people recommended that Ecology provide 

information on fish consumption rates for the general population. Ecology has worked 

with the University of Washington to review national dietary surveys that provide 

information on fish consumption rates for the general population, and has included the 

results of that review in the revised document. 

 Recreational fisher studies. Several people recommended that Ecology provide

information on fish consumption rates for recreational fishers. Ecology reviewed 

available studies on recreational fishers. Based on that review, Ecology has conducted an 
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independent assessment, provided in a separate Technical Issue Paper (Ecology, 2012),

that details recreational fish consumption studies conducted in Washington. Ecology has 

incorporated the results of that review into this revised Technical Support Document.

 Asian Pacific Islander (API) studies. Several people recommended that Ecology consider 

additional information on the fish dietary habits of API populations. Ecology has 

incorporated additional information on API populations into this revised Technical 

Support Document.

 Estimating long-term consumption rates. Several people expressed concerns about using 

the results from short-term episodic dietary studies to estimate long-term upper percentile 

fish consumption rates. Ecology has reviewed and evaluated methods for adjusting shortterm episodic dietary information to provide fish consumption estimates and percentiles. 

These statistical corrections were used to estimate annual fish consumption rates for the 

general population from 2-day national survey data.

 Salmon. Ecology received a wide range of comments on salmon, their life cycles and 

survival strategies, and salmon contaminant body burdens. This document provides fish 

consumption estimates with and without salmon from several fish dietary surveys of 

Pacific Northwest populations. Where available, fish consumption estimates are tabulated 

for anadromous and non-anadromous species. Additional information on salmon 

contaminant body burdens is provided in Appendix C and in the Technical Issue Paper,

Salmon Life History and Contaminant Body Burdens (Ecology, 2012). 

 Analysis of regional fish dietary information. In Version 1.0 of this Technical Support 

Document, Ecology provided the results of a statistical evaluation from fish dietary surveys

of Pacific Northwest populations. Ecology’s evaluation provided fish consumption 

estimates between the 80th and 95th percentiles of the fish consumption distribution. Several 

people provided comments regarding policy choices embedded in this evaluation. Ecology 

has reviewed these comments, and in order to facilitate broad consideration in the process 

of revising the Water Quality Standards for Surface Waters, this version of the Technical 

Support Document does not provide a recommended range for fish consumption rates. 

Discussion is provided in Chapter 4.

 Policy statements and recommendations. This Technical Support Document is focused 

on finfish and shellfish resources in the Pacific Northwest, and Washington State fishconsuming populations. It includes information from fish dietary surveys of Pacific 

Northwest populations and national general population data. Ecology acknowledges that 

there are many policy decisions associated with estimating fish consumption rates for 

Washington State fish-consuming populations. Some of these policy issues are noted in 

Chapter 6. This document, however, does not provide a thorough discussion of policy

choices. The issues are identified only to assist readers in a broader understanding of the 

context in which fish consumption rates are considered.
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1.5 Organization of this document

The remainder of this document is organized as follows. 

Chapter 2: Washington Fish Resources and Fish-Consuming Populations

Available information indicates that some Washington residents consume locally harvested

finfish and/or shellfish. In addition, several population subgroups (including Native Americans

and Asian and Pacific Islanders) consume large amounts of finfish and shellfish. This chapter

summarizes available information on state water resources that support fishing practices. 

Regional differences are acknowledged and the size and demographic characteristics of 

Washington finfish and shellfish consumers and consuming populations are identified. 

Chapter 3: Methodology for Assessing Fish Consumption Rate Information

Several approaches are available for developing estimates of finfish and shellfish consumption. 

Although surveys are generally considered to be the best approach for developing these 

estimates, a number of design features determine whether a particular survey provides a 

technically defensible basis for agency decision making. This chapter reviews those design 

features and outlines the factors considered when evaluating studies. 

Chapter 4: Fish Consumption Survey Data that Apply to Washington Fish Consumers

This chapter reviews and analyzes available fish consumption survey data for the general 

population, Pacific Northwest Native American tribes, Asian and Pacific Islanders, and 

recreational fishers. It includes a discussion of variability and uncertainty in the survey data, and 

summarizes key findings. 

Chapter 5: Sources of Uncertainty and Variability

When making regulatory decisions, it is important to consider the uncertainties associated with 

available data and the variability across individuals, fish species, and geographic areas. This 

chapter provides a high-level summary of important sources of uncertainty and variability in fish 

consumption surveys used to estimate finfish and shellfish consumption rates.

Chapter 6: Using Scientific Data to Support Regulatory Decisions

This chapter highlights some of the policy choices that will be needed when using fish consumption 

rates to support regulatory decisions. The discussion includes brief descriptions of particular 

regulatory issues and a range of examples to illustrate how agencies have resolved each issue.

Appendices

Included here is other fish consumption information used for regulatory decision making

including fish species found in Washington, information on additional tribal studies, 

correspondence from the Columbia River Inter-Tribal Fish Commission and University of 

Washington, further discussion on the challenges of risk assessment and salmon consumption, a 

glossary of terms, and a complete list of reference citations presented alphabetically by author.
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Chapter 2: Washington Fish Resources and 

Fish-Consuming Populations

2.1 Introduction

Washington is home to a wide range of water resources that support commercial, recreational, 

and subsistence fishing and harvesting. Many Washington residents consume some local finfish 

or shellfish. Several population groups consume larger amounts of finfish and shellfish than the 

general population. These include members of Native American tribal nations, Asian and Pacific 

Islanders, and people who fish recreationally (recreational fishers). 

Ecology’s review of available data on fish harvests identified the commercial, tribal, and 

recreational harvesting of multiple species, including groundfish, Pacific halibut, coastal pelagic 

species, highly migratory species, salmon, other anadromous species and eggs, and shellfish. 

Similarly, recreational sport fishing is structured around a multispecies fishery, and hundreds of 

thousands of sport anglers harvest fish throughout Washington.

Salmon are of particular importance in Washington, and questions about salmon are discussed at 

several points in this report. Salmon are harvested from both fresh and marine waters. The Puget 

Sound basin and the Columbia River basin dominate the areas of harvest. Steelhead and salmon 

(from both fresh and marine waters) accounted for about half of the recreational sport harvest 

(close to 400,000 fish) in 2006.

This chapter is organized into the following sections: 

 Fish resources. A summary of finfish and shellfish resources in Washington. 

 Estimated number of Washington fish consumers. This section provides rough estimates 

on the number of adults and children in Washington who regularly eat finfish and/or 

shellfish. 

 High fish-consuming populations. This section defines high fish consumers and identifies 

and describes subpopulations in Washington generally known to be high fish consumers.

Washington waters support large finfish and shellfish populations and commercial, tribal, and 

recreational harvests.

2.2 Washington fish resources

Washington has more than 500 miles of Pacific coast shoreline and over 2,000 combined miles 

of Puget Sound, San Juan Islands, Strait of Juan de Fuca, and Hood Canal shoreline. This 

shoreline provides habitat for marine finfish and shellfish. In addition, the state has 4,000 rivers 
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and streams, stretching over 50,000 miles. Many streams and rivers have seasonal salmon and 

steelhead runs. State waters also include more than 7,000 lakes, with over 2,500 lakes at alpine 

elevations, and more than 200 reservoirs that provide additional fishing opportunities. Many 

freshwater areas are open for fishing year-round (WDFW, 2010). 

A large variety of finfish and shellfish are available for harvesting in Washington (WDFW, 

2010, p. 17–30). The Washington Department of Fish and Wildlife (WDFW) has identified more 

than 50 species of edible freshwater fish and almost as many in marine waters (WDFW, 2010, p. 

17–30). (See Appendix C for information on finfish and shellfish species harvested in 

Washington.)

A study to summarize the economic benefits of Washington’s non-treaty commercial and 

recreational fisheries provides information on the valuation and numbers of commercial and 

recreational finfish and shellfish harvested throughout Washington. In 2006, commercial fish 

landings from non-treaty fisheries totaled more than 109 million pounds. The Washington 

coastal area is the largest contributor to commercial fish harvesting, accounting for 85 percent of 

total pounds landed (WDFW, 2008a). 

The fish consumption rate tabulations in this technical support document are derived from 

national fish dietary data and from fish dietary surveys from the Pacific Northwest. The tribal 

fish dietary surveys from the Pacific Northwest document fish locally harvested and consumed. 

Independent and separate documentation from three different Washington State agencies 

(WDFW, Washington State Department of Health [DOH], and Ecology) document the harvest 

and consumption of local aquatic resources, including finfish and shellfish. However, data gaps 

remain regarding the exact locations of where fish and shellfish are harvested in Washington and 

how the fish are then made commercially available for consumption.

2.2.1 Washington’s commercial fisheries

Washington’s commercial fisheries include harvest of groundfish, Pacific halibut, coastal pelagic 

species, highly migratory species, salmon (including eggs), other anadromous species, and 

shellfish. In 2006, nontribal commercial fish landings from Washington fisheries totaled 

approximately 109.4 million pounds. 

In 2006, groundfish (bottom-dwelling fish or bottomfish) composed the state’s largest 

commercial fishery. Groundfish accounted for 54 percent of the commercial catch from 

Washington waters, with approximately 59.2 million pounds landed. Shellfish landings 

represented the state’s second-largest commercial fishery, accounting for almost 25 percent of 

the commercial catch, with approximately 25.8 million pounds landed in 2006.
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Salmon is a major contributor to Washington’s commercial fishing industry. Salmon landings 

from Washington waters totaled about 11 million pounds, accounting for about 10 percent of the 

commercial catch in 2006. 

Table 3 illustrates the extent of Washington’s commercial fisheries, showing pounds of fish 

harvested from Washington non-treaty fisheries in 2006.

Table 3. Commercial Fish Landings from Washington Non-treaty Fisheries in 

2006

Species Pounds Landed

Groundfish (excluding halibut) 59,217,924

Total shellfish 25,789,641

Salmon 11,020,228

Coastal pelagic species 8,233,078

Highly migratory species 4,802,666

Other anadromous fish and eggs 158,621

Pacific halibut 135,868

Total commercial pounds landed of finfish/shellfish 109,358,026

Source: Adapted from WDFW, 2008a, Table 1, p. 6. 

2.2.2 Washington’s recreational fisheries

Traditionally, Washington’s most intense freshwater fishing activity begins during the last 

weekend in April. Based on estimates from WDFW, over 300,000 anglers fish during opening 

weekend of the lowland lakes season. To meet this demand, WDFW stocks about 19 million 

trout and kokanee fry annually. Another 3 million catchable trout are planted in lakes and 

streams. In addition, many lakes receive additional sterile rainbow trout. Most rivers and streams 

throughout Washington are managed to produce wild trout, coastal and west slope cutthroat, 

salmon, and steelhead (WDFW, 2010).

An estimated total of 824,000 people fished in Washington in 2006, including both finfishing 

and shellfishing. Of these, an estimated 725,000 anglers (88 percent of the total) were state 

residents who fished a combined total of about 8.5 million days that year. This equals 93 percent

of all fishing days available for licensed recreational sport fishing (WDFW, 2008a). 

Marine recreational fishing and shellfishing occurs along more than 500 miles of the Pacific 

Coast shoreline and more than 2,000 combined miles of shoreline throughout Puget Sound, the 

San Juan Islands, the Strait of Juan de Fuca, and Hood Canal (WDFW, 2008a). As previously 

noted, freshwater recreational fish inhabit more than 4,000 rivers and streams extending over 

50,000 miles, 7,000 lakes, and 200 reservoirs (WDFW, 2010, 2012). The following are selected 

highlights of recreational sport fishing and shellfishing that identify the species available for 

recreational anglers across Washington:
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 Recreational fishing for shad on the Columbia River with several million shad passing 

through Bonneville Dam annually.

 WDFW lists state record catches for more than 50 freshwater species of fish (e.g., 

rainbow trout, Beardslee rainbow trout, brown trout, and numerous other trout species).

 Recreational sturgeon fishing on the Columbia River.

 Marine recreational seasonal fishing for lingcod, halibut, and rockfish as well as other 

marine bottomfish.

 Recreational shellfishing for oysters, clams, shrimp, and crab throughout Puget Sound, 

Hood Canal, the San Juan Islands, and the Strait of Juan de Fuca.

Recreational sport fishers harvest finfish in fresh and marine waters and shellfish along marine 

shorelines. Approximately 22 million trout and kokanee are stocked annually in lakes and inland 

streams and are available to recreational anglers. Tables 4 and 5 list information on the 2006 

sport finfish and shellfish harvests, respectively. These numbers demonstrate the extent of 

recreational fishing in Washington. 

Approximately two-thirds of the 2006 catch for bottomfish was harvested in coastal waters, with 

the remaining one-third harvested from the marine waters of Puget Sound.10 Approximately 74 

percent of the steelhead and 95 percent of the sturgeon harvested from Washington waters in 

2006 were from the Columbia River and its tributaries. 

Table 4. Number of Recreational Finfish Caught in Washington Waters in 2006 

by Species and Region

Species/Group Number of Finfish Harvested from each Catch Region

Puget Sound Coast Columbia River* Unknown Total

Bottomfish 112,457 295,151 --- --- 407,608

Salmon – freshwater 98,576 7,186 65,817 1,227 172,806

Steelhead 12,709 15,415 80,294 477 108,895

Salmon – marine 65,423 43,027 --- --- 108,450

Albacore --- 18,941 --- --- 18,941

Sturgeon 203 456 15,695 182 16,536

Pacific halibut 2,727 6,977 692 --- 10,400

Total 292,095 387,153 162,498 1,886 843,636

Source: Adapted from WDFW, 2008a, Table 6, p. 17.

* Columbia River region includes the Columbia River and all tributaries and the Snake River.

 

10 The term coastal waters refers to waters having a coastline that forms the boundary between land and freshwaters and marine and/or 

estuarine waters. This term encompasses all freshwaters of statewide significance (lakes, rivers, streams, etc.) and those marine and/or 

estuarine waters extending from the landward edge of a barrier beach or shoreline of coastal bay to the outer extent of the continental shelf.
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Table 5. Pounds of Shellfish Taken Recreationally From Washington Waters in 

2006, by Species and Region

Species/Group

Pounds of Shellfish Harvested from each Catch Region

North Puget 

Sound

South Puget 

Sound Strait Coast Columbia River Totals

Dungeness crab 3,330,004 271,167 261,540 --- --- 3,862,711

Razor clams --- --- --- 3,601,000 3,601,000

Oysters 19,129 632,966 --- --- --- 652,095

Other clams 93,038 252,628 --- --- --- 345,666

Shrimp 23,520 87,996 1,950 --- --- 113,466

Source: Adapted from WDFW, 2008a, Table 7, p. 17.

All values are in pounds except oysters, which are in number of oysters harvested.

Salmon were harvested in both fresh and marine waters, with approximately 60 percent of the 

salmon harvest occurring in marine waters. Puget Sound salmon accounted for approximately 

60 percent of all salmon harvested in marine waters. In fresh water, approximately 57 percent of 

salmon are harvested in Puget Sound streams and 38 percent are from the Columbia River and its 

tributaries. 

Dungeness crab taken from north Puget Sound waters accounted for more than 85 percent of the 

2006 statewide harvest. Razor clams are only harvested from coastal beaches. Tens of thousands 

of recreational sport clammers harvest razor clams on weekends during clamming season

(WDFW, 2008a). 

2.3 Washington fish-consuming population

Washington is home to a culturally and ethnically diverse population that is projected to become 

more diversified over the next 20 years. The Washington Office of Financial Management 

(OFM) provides the following demographic information (U.S. Census Bureau, 2000, 2010)

11

: 

 Total Washington Population as of April 1, 2010 6.72 million

Adults (74 percent of the population is estimated at over 18) 5.14 million

Children (between 0 and 18 years of age) 1.71 million

OFM projects that the Washington population will increase by 1.8 million people in the next 

20 years: 12

 

11 Population estimates are based on census data, and may vary depending on the census accounting procedures used to generate estimates 

for specific subpopulations. Therefore, subpopulation estimates and totals may not align perfectly. 

12 Population projections are provided for illustrative purposes; they are not intended as precise estimates. Population projections presented in 

this document do not reflect 2012 redistricting updates. 
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 Projected Total Washington Population, 2030 8.54 million

Projected children (between 0 and 18 years of age) 2030 2.06 million

2.3.1 Estimated number of fish consumers in Washington

The general population is made up of people with a variety of dietary preferences. Some 

consume fish frequently, some infrequently, and some potentially never. (However, even people 

who report they don’t eat fish may consume some fish in processed foods like salad dressing, 

Worcestershire sauce, and cheese spread.) Per capita rates that take into account the entire 

population will differ from rates derived from consideration of so-called consumer only data. For 

protection of people who eat fish, the population of interest is generally considered to be fish 

consumers (CalEPA 2001, page 13; Oregon DEQ 2008; U.S.EPA 2002b).

People consume finfish and shellfish obtained from a variety of sources. Information about fish 

consumed by the general Washington population is available only through estimates.

13 While 

there are uncertainties associated with these estimates, they are useful in providing context to the 

discussion about fish consumption rates. 

First, the total number of fish consumers was estimated. A fish consumer is someone who eats 

finfish or shellfish at least occasionally. Then a definition of high fish consumer was used to 

suggest the number of people in the general population at the high end of the exposure

distribution. These estimates provide only a rough number of fish consumers and no information 

about the source of the fish. Ecology also reviewed available information on certain ethnic 

groups that consume fish from local waters. 

To estimate the number of fish consumers in Washington, and how much fish they consume, 

Ecology considered multiple estimation methods. This is consistent with the approach taken by 

the Oregon Department of Environmental Quality (Oregon DEQ) Human Health Focus Group. 

Using 2010 demographic information provided by the Washington OFM, Ecology estimates that 

between 1.4 and 3.8 million Washington adults (and approximately 290,000 Washington children 

0 to 18 years old) are fish consumers. These upper and lower estimates were developed using two 

different methods, as described below: 

 Low Estimate: Based on national survey data. The first approach resulted in the lower of 

the two estimates. It was developed using Washington population data and information 

on the percentage of fish consumers reported in Estimated Per Capita Fish Consumption 

 

13 These estimates use the EPA 2002 data and are consistent with the methodology used by the Oregon Human Health Focus Group. They do 

not use the National Health and Nutrition Examination Survey (NHANES) results because these estimates were developed before that work 

was complete.
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Washington State Behavioral Risk 

Factor Surveillance System

The BRFSS telephone survey is a 

valuable health management tool 

used by DOH to collect health-based 

information and monitor the public’s 

behavioral risk factors that may

contribute to a person’s health. The 

BRFSS primarily collects data on 

chronic diseases, injuries, infectious 

illnesses, and the behavioral factors 

underlying these conditions. 

in the United States (U.S. EPA, 2002a).

14 For this estimate of fish consumers in 

Washington, Ecology assumed that Washington dietary habits are similar to those for the 

United States as a whole. The Oregon DEQ Human Health Focus Group used this 

approach to prepare estimates of fish consumers in Oregon.15 (See Chapter 4 for 

additional information on estimated United States per capita fish consumption.)

o Adults. EPA found that 28 percent of adults interviewed in the national survey 

were fish consumers (U.S. EPA, 2002a, Section 5.1.1.1, Table 4). Assuming that 

a similar percentage of Washington’s 5.1 million adults also consume fish, 

Ecology estimates that approximately 1.4 million adults in Washington currently 

eat some amount of fish. 

o Children. EPA found that 16 to 19 percent of children (ages 0 to 18) included in

the national survey were fish consumers (Moya, 2011, personal 

communication).

16

 Assuming that 17 percent of Washington’s 1.7 million

children also consume fish, Ecology estimates that there are approximately 

290,000 children in Washington who currently eat some amount of fish. 

 High Estimate: Based on Washington State 

Department of Health survey. The second approach 

resulted in the higher estimate. It was developed using 

Washington population data and information compiled 

by the DOH. DOH used the Behavioral Risk Factor 

Surveillance System (BRFSS) to compile information 

on fish consumption habits of randomly selected 

Washington residents.17 This work was done over a 4-

year period; it was designed to improve DOH’s 

understanding of the percent of the Washington 

population that consumes fish.

 

14 This percent value may underestimate the fraction of fish consumers in Washington State because other parts of the United States do not 

have the fisheries resources available in Washington State.

15 Ecology acknowledges the limitations of the national fish dietary data; this approach employed a 2-day dietary recall survey methodology 

where respondents who did not report eating fish on one of the two survey days were counted as non-consumers and averaged with 

consumers as a zero. As noted by the EPA 2011 Exposure Factors Handbook, p. 10-16, “... short-term consumption data may not accurately 

reflect long-term eating patterns and may under-represent infrequent consumers of a given fish species. This is particularly true for the tails 

(extremes) of the distribution of food intake. Because these are 2-day averages, consumption estimates at the upper end of the intake 

distribution may be underestimated are used to assess acute (i.e., short-term) exposures.”

16 Approximately 18 percent of the U.S. general population ages 16 – 21 are fish consumers; approximately 31 percent of the U.S. general 

population ages 20 – 50 are fish consumers. Information is based on EPA’s reexamination of the National Health and Nutrition Examination 

Survey (NHANES) and the 2002 per capita fish consumption report. 

17 The BRFSS is sponsored by the U.S. Centers for Disease Control and Prevention (CDC) and is a probability-based telephone survey of noninstitutionalized adults, ages 18 years and over.
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o DOH found that in 2002 and 2004, 78 percent and 74 percent, respectively, of 

adults in Washington consumed store-bought fish. In 2005, 57 percent of the 

adults surveyed reported eating fresh fish purchased at a local grocery store or 

fish market (frozen fish excluded). Among Washington fish consumers, 

44 percent consumed salmon, 20 percent consumed halibut, 13 percent consumed 

cod, and 6 percent consumed tuna. 

o Although these data were intended for use by DOH in developing fish 

consumption advisory programs, Ecology, after consultation with DOH, 

determined that the information is appropriate for estimating the total number of 

fish consumers in Washington as needed for this report.

o Working with DOH, Ecology estimated that between 2.9 and 3.8 million 

Washington adults currently consume some amount of finfish and/or shellfish. 

Table 6 provides estimates of Washington fish consumers calculated by Ecology 

using the DOH data. 

Table 6. Estimated Washington Fish Consumers Based on Washington DOH 

Survey Data

Years for Projected 

Population Estimates

Estimated number of Washington adults who consume:

Store-bought fish Fish from local stores 

or markets Salmon

2010 3.80 million a 2.93 million b 1.67 million

2030 4.88 million 3.76 million 2.90 million

a. This estimate assumes 74 percent of the total adult population consuming store-bought fish, per the DOH 2004 data.

b. This estimate assumes 57 percent of the total adult population consuming fresh fish from local stores or markets, per the DOH 2005 data.

Population projections are included to illustrate that estimates of total fish consumers in 

Washington are expected to increase as the population grows. 

2.3.2 Estimated number of high fish-consuming adults

Pacific Northwest fish dietary information shows that certain populations—Native American 

tribes, Asian Pacific Islanders, and recreational fishers—consume fish at much higher rates than 

the average U.S. consumer and at higher rates than those used to establish surface water cleanup 

standards. Because these populations consume fish at higher rates than the national rates used in 

Ecology’s regulations, their exposure to contaminants in fish may be underestimated and these 

populations may therefore be at a higher risk. For this reason, Ecology has estimated the number 

of high fish consumers in the general population. The estimate is intended only to provide 
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Selected results from BRFSS telephone survey

 In 2005, about 44 percent of all adults surveyed consumed 

salmon in the past 30 days.

 In 2005, about 20 percent of all adults surveyed consumed 

halibut in the past 30 days.

 In 2005, about 13 percent of all adults surveyed consumed cod 

in the past 30 days. All other species were consumed by <10

percent of survey participants.

 In 2004, about 74 percent of all adults surveyed followed fish 

advisories when they thought the fish advice applied to them. 

However, only about 44 percent of all adults surveyed thought 

the fish advisory applied to them.

 In 2004, about 98 percent of the pregnant women surveyed 

followed fish advisories when they thought the fish advice 

applied to them. However, only about 48 percent of the 

pregnant women surveyed thought the fish advisory applied to 

them.

 In 2004, about 35 percent of all adults surveyed reported eating 

sport fish in the past year harvested from Washington State 

waters. Among different races, about 47 percent of adult 

American Indians, 38 percent of Pacific Islanders, 23 percent of 

Asians, and 19 percent of Blacks reported eating sport fish in 

the past year.

 In 2004, about 35 percent of adults living in Western 

Washington counties (Clallam, Clark, Cowlitz, Grays Harbor, 

Jefferson, King, Kitsap, Lewis, Mason, Pacific, Pierce, San 

Juan, Skagit, Skamania, Snohomish, Thurston, Wahkiakum, 

and Whatcom) reported eating any sport fish in the past year. 

About 40 percent of adults living in counties along the Columbia 

River reported eating any sport fish in the past year, while 34

percent of adults living in Puget Sound counties and 57 percent

of adults living in outer coastal counties reported eating sport 

fish in the past year.

Fish consumption-related BRFSS telephone survey questions

BRFSS telephone survey questions related to fish dietary habits provide DOH with information on:

 Types and frequency of finfish consumption.

 Perceptions about the benefits of eating fish (are fish healthy to eat).

 How, where, or in what form the public receives information about fish health advisories that limit fish 

consumption based on mercury contamination.

 Whether people are following the fish advisories.

 Regional differences regarding frequency and types of fish consumed.

context; it does not provide 

information on where these 

consumers obtain their fish and 

shellfish. Specifically, it does not 

address the question of whether 

this is locally harvested.18

Information elsewhere in this 

report notes that many people in 

Washington consume fish from 

local waters—for example, 

recreational anglers. 

For purposes of this estimate, high 

fish consumers are persons who 

consume fish at or above the 90th

percentile of the national per 

capita fish consumption rate. The 

fish consumption rate that 

corresponds to the 90th percentile 

national per capita consumption 

depends on the dataset and 

statistical method used. The choice 

for defining high fish consumers 

this way was made for illustrative 

purposes. It is consistent with EPA 

regulatory policy and procedures 

and is the definition used by the 

Oregon Human Health Focus Group.

 

18 The term locally harvested is used to identify the source of fish. It is used to distinguish fish harvested locally from fish purchased and coming 

from unknown and potentially non-local (out of state) sources.
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Based on EPA’s Estimated Per Capita Fish Consumption in the United States, the 90th percentile 

of the estimated national fish consumption rate for adult fish consumers only corresponds to 250 

g/day (U.S. EPA, 2002a).

19 (250 grams is approximately 0.55 pound or 8.8 ounces.) This value is 

used to define high fish-consuming adults in this Technical Support Document. (See Chapter 6 

for a discussion of per capita vs. consumer-only fish consumption rates.)

Ecology has also evaluated national fish dietary information using data from the U.S. 

Department of Agriculture’s National Health and Nutrition Examination Survey (NHANES), 

2003–2006. This analysis is discussed in Chapter 4. Based on this evaluation, the 90th percentile 

of the estimated national per capita fish consumption for adult consumers is in the range of 42.5 

g/day to 128 g/day, depending on the statistical method used. 

Ecology estimates that between approximately 140,000 and 380,000 Washington adults are high 

fish consumers (Table 7). Based on OFM population projections, this number could increase by 

27 percent over the next 20 years. 

2.3.3 Assumptions

This estimate is based on a number of assumptions that Ecology believes to be reasonable: 

 Between approximately 1.4 million and 3.8 million Washington adults consume some 

amount of fish on a regular basis. As described in the previous sections, this range is 

based on current population data and estimates indicating that between 28 and 74 percent

of Washington adults regularly consume fish.20

 High fish consumers are defined as people who consume more than the 90th percentile 

estimate of finfish and/or shellfish per day.21 The 90

th percentile of the fish consumption 

distribution may be based on national data as evaluated by EPA in 2002 or by Ecology in 

2012 using the 2003–2006 NHANES data. Estimates of adult fish consumption rates vary 

depending on the statistical methodology used to evaluate the data. 

 The dietary habits and patterns for Washington fish consumers are similar to those 

reported for the United States fish consumers.

22

 

19 Corresponds to the 90th percentile intake of finfish and shellfish for adult consumers only, based on uncooked fish weight. See U.S. EPA, 

2002a, Section 5.2.1.1, Table 4.

20 The 2003 – 2006 NHANES dietary information provides reasonably comparable low end percent estimates of fish consumers as evaluated in 

EPA, 2002, and Polissar et al., 2012.

21 Unless otherwise noted, in this document the term fish consumption rate refers to consumption of both finfish and shellfish. 

22 This assumption is discussed further in the conclusions to this chapter. 
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Table 7. Estimated Number of Fish Consumers among the General Washington 

Adult Population

Year

Total Population

of Washington 

Adults

Estimated Number of Washington 

Adult Fish Consumers

Estimated Number of Washington 

Adults who are High Fish Consumers 

(90th percentile or above)

Low Estimate High Estimate Low Estimate High Estimate

2010 5.14 million 1.44 million 3.81 million 144,000 381,000

2030 6.59 million 1.85 million 4.88 million 185,000 488,000

As noted, estimates of fish consumption that correspond to the 90th percentile of the distribution 

may vary depending on the statistical methods used to evaluate the national data. Regardless of 

the national dataset used and the statistical methodology used to evaluate the national data, 

population estimates for Washington State fish-consuming adults based on the 90th percentile of 

the fish consumption distribution indicate that there are a large number of adults in Washington 

who consume fish (for adult low and high estimates approximating 30 to 75 percent of the total 

Washington State population). Note that the information used for estimates of fish consumption 

among the general adult population is for total fish consumed from all sources.

2.3.4 Estimated number of high fish-consuming children

For purposes of this report, Ecology defines children as high fish consumers if they consume fish 

at or above the 90th percentile of the estimated national per capita fish consumption rate for 

children. As discussed above, the fish consumption rate that corresponds to the 90th percentile 

depends on the dataset and statistical method used to evaluate the data. Based on EPA’s 

Estimated Per Capita Fish Consumption in the United States, the 90th percentile of the estimated 

national per capita fish consumption rate for children who eat fish corresponds to 190 g/day

(U.S. EPA, 2002a).

23 (190 grams is approximately 0.42 pound or 6.7 ounces.) Ecology’s 

evaluation of the NHANES 2003–2006 data, as described in Section 4.2.2, did not include 

estimation of fish consumption rates for children. 

Ecology estimates that there are approximately 29,000 Washington children who are high fish 

consumers (Table 8). Based on OFM population projections, this number could increase by 83

percent over the next 20 years. 

This estimate is based on the following assumptions that Ecology believes to be reasonable:

 Approximately 290,000 Washington children eat some amount of fish on a regular basis. 

As discussed in an earlier section, this estimate is based on current population estimates 

and national survey results that indicate that 16 to 19 percent of children reported eating 

some amount of finfish or shellfish. 

 

23 Corresponds to the 90th percentile intake of finfish and shellfish for consumers only, age 14 and under. Based on uncooked fish weight.
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 Children are defined as high fish consumers when they consume more than the 90th

percentile estimate of finfish and/or shellfish per day. The 90th percentile of the fish 

consumption distribution to define a high fish consumer may be applied to the national 

data as evaluated by the EPA (U.S. EPA, 2002a, Section 5.2.1.1, Table 4) or to the 2003–

2006 NHANES data. Estimates of children’s fish consumption will vary depending on 

the statistical methodology used to evaluate the data. The information in Table 8 suggests 

that about 20 percent of the total children in Washington State are fish consumers.

 The dietary habits and patterns for Washington fish consumers are similar to those 

reported for the United States fish consumers. 

Table 8. Estimated Number of Child Fish Consumers among the General 

Washington Population

(Children Younger Than 18 Years Consuming Large Amounts of Finfish or Shellfish)

Year

Total Population 

of Children 

(18 and younger)

Estimated Number of 

Washington Child Fish 

Consumers

Estimated Number of Washington 

Children who are High Fish 

Consumers (90

th percentile or above)

2010 1.71 million 290,000 29,000

2030 2.06 million 350,000 35,000

2.4 High fish-consuming populations

Some population groups consume especially large amounts of finfish and shellfish as part of 

traditionally influenced diets. These include Native Americans and Asian, Pacific Islanders, and 

subsistence and recreational fishers.

2.4.1 Washington Native American Tribes

Washington is home to 29 federally recognized and seven non-federally recognized Native 

American tribes (Governor’s Office of Indian Affairs, 2010). Traditional fishing areas for tribes 

cover essentially all of Washington. 

The Washington OFM estimates there are approximately 104,000 American Indian and Alaska 

natives in Washington. Approximately 70 percent of the American Indian and Alaska native 

population is 18 years of age or older (73,500 adults) (U.S. Census Bureau, 2000, Table 2). OFM 

estimates there are 33,600 American Indian and Alaska natives between the ages of 0 and 18 years.

OFM projects that the total number of Native Americans in Washington will increase from 

104,000 in 2010 to approximately 146,000 by the year 2030:

24

 

24 2010 population numbers are based on the 2010 Census redistricting data. 2030 estimates are as of the OFM 2006 Population Projections 

by Age, Sex, and Race.
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 Population of American Indian and Alaska natives in Washington 104,000

Adults (70 percent of population is estimated at over 18) 73,500

Children (between 0 and 18 years of age) 33,600

 2030 Population Projection 146,000

2.4.2 Asian and Pacific Islanders

Asian and Pacific Islander (API) populations include Native Hawaiians and peoples from other 

Pacific islands. The Washington OFM estimates there are approximately 522,000 Asian and 

Pacific Islanders currently residing in Washington (U.S. Census Bureau, 2000, Table 2). Finfish 

and shellfish consumption among this population in Washington has been documented. 

Approximately 75 percent of the current API population is 18 years of age or older (405,000

adults) (Sechena et al., 1999). There are 138,000 Asian and Pacific Islanders between the ages of 

0 and 18 years.

OFM projects that the total number of Asian and Pacific Islanders in Washington will increase 

from 522,000 in 2010 to approximately 825,000 by the year 2030:

25

 Population of Asian and Pacific Islanders in Washington 522,000

Adults (75 percent of the population is estimated at over 18) 405,000

Children (between 0 and 18 years of age) 138,000

 2030 API Population Projection 825,000

2.4.3 Subsistence and recreational fishers

Approximately 824,000 people fished in Washington State during 2006; of these, 725,000 were 

Washington residents and 99,000 were nonresidents. Washington residents fished a total of 8.5 

million days in 2006, an average of 12 days per angler (U.S. Department of the Interior and U.S. 

Department of Commerce, 2008).

Washington is home to some number of persons engaged in a subsistence lifestyle. 

Considerations related to subsistence fishing for Native American tribes in the Pacific Northwest 

have been identified (Donatuto and Harper, 2008; Harper and Harris, 2008). However, due to a 

lack of data, at this time Ecology is unable to estimate the number of subsistence fishers in 

Washington. 

 

25 2010 population numbers are based on the 2010 Census redistricting data. 2030 estimates are as of the OFM 2006 Population Projections 

by Age, Sex, and Race.
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2.5 Sources of Fish Consumed

Fish consumption rate tabulations in this technical support document are derived from national 

fish dietary data and fish dietary surveys from the Pacific Northwest. The tribal fish dietary 

surveys from the Pacific Northwest provide information about the types of fish that are locally 

harvested and consumed. These tribal fish dietary surveys document locally harvested fish from 

usual and accustomed tribal treaty areas throughout the Columbia River basin and throughout 

Puget Sound. 

For example, the 1994 Columbia River Inter-Tribal Fish Consumption Survey reflects fish 

harvest rates throughout the Columbia River basin for over 80% of the respondents. 

Independent and separate documentation from three different Washington State agencies 

(WDFW, DOH, and Ecology) document the harvest and consumption of local abundant aquatic 

resources, including finfish and shellfish. For example, WDFW has documented the amounts of 

different shellfish harvested from various regions in Washington State (see Table 5). 

Data gaps remain regarding exact locations where fish and shellfish are harvested in Washington 

State, and information about their commercial availability in state-wide grocery stores and local 

food markets. 

2.6 Summary

From current demographic information, Ecology has estimated the total number of Washington 

fish consumers. Ecology reached its estimate after working with OFM to use census data and 

applying national and Washington fish consumption rate estimates to the general Washington 

population. There may be some variation in the adult and child fish-consuming population 

estimates for Washington State depending on the dataset and statistical methods used to evaluate 

national fish dietary information. Adult and child fish-consuming population estimates presented 

in this report are based on a similar analysis conducted by the 2008 Oregon DEQ Human Health 

Focus Group Report (Oregon DEQ, 2008).

Ecology believes that the population estimates for Washington State adult and child fish 

consumers provided in this report are reasonable estimates that help gauge and approximate the 

number of fish consumers. There are a large number of adults and children in Washington State 

who routinely consume finfish and shellfish.

According to Ecology’s analysis, there are between 1.4 and 3.8 million Washington adults 

(18 years of age or older) who are fish consumers.26 The number of adult fish consumers is 

 

26 This includes a large number of recreational anglers. For example, the Washington Department of Fish and Wildlife estimates there were 

824,000 recreational anglers (both finfishing and shellfishing) in Washington in 2006. 
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projected to increase by up to 27 percent as Washington’s population grows over the next 

20 years. 

Ecology estimates that approximately 290,000 Washington children (0 to 18 years of age) 

consume fish. It should be noted that this estimate was developed using national survey data for 

the general population. Studies have shown that people living in coastal states tend to consume 

finfish and shellfish at a higher frequency and higher rates than inland states (Moya, 2004).

27

Ecology is not aware of Washington surveys that have examined child fish consumption 

frequency for the general population. The number of Washington children who eat some type of 

fish is also projected to increase as Washington’s population grows over the next 20 years. 

For this report, Ecology defined high fish consumers as all Washington adults and children who 

consume finfish and/or shellfish at or above the 90th percentile estimates from surveys of 

national per capita consumption. Based on data presented by the EPA (U.S. EPA, 2002a), these 

estimates correspond to 250 g/day and 190 g/day for adults and children, respectively.

 Ecology estimates that there are between 140,000 and 380,000 Washington adults who 

are high fish consumers. Ecology believes that the high end of this range provides a 

reasonable estimate of the number of high fish consumers in Washington. The high end 

of the range is based on information collected by the Department of Health on fish 

consumption habits of Washington residents. 

 Ecology estimates that there are approximately 29,000 Washington children who are high 

fish consumers. 

Certain population groups, including Native Americans and Asian and Pacific Islanders, 

consume large amounts of finfish and shellfish.28

 According to OFM estimates, there are approximately 104,000 Native American and 

Alaska natives in Washington. 

 According to OFM estimates, approximately 522,000 Asian and Pacific Islanders live in 

Washington.

In summary, considerable quantities of finfish and shellfish are harvested for consumption in 

Washington, both recreationally and commercially. Many Washington residents harvest and 

presumably consume finfish and shellfish from local waters (WDFW, 2008a, 2012). High fish 

consumers include several population groups known to consume larger amounts of finfish and 

shellfish than the general population. 

 

27 National fish consumption studies are typically carried out over a broad geographical area, including multiple states. Consequently, national 

studies may underestimate the rates and frequencies for states like Washington.

28 Chapter 4 discusses further the consumption rates, patterns, and species consumed by Native Americans and Asian and Pacific Islanders. 
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Chapter 3: Methodology for Assessing

Fish Consumption Rate Information

3.1 Introduction

Researchers use a variety of methods for estimating the amount of finfish and shellfish 

consumed. Surveys are generally considered to be the best approach for collecting data; 

however, a number of design features determine whether a particular survey will provide a 

technically defensible basis for agency decision making. Technical defensibility means that the 

survey stands up to technical and scientific scrutiny and provides a solid technical basis for 

regulatory decisions. Among other factors, a survey that is technically defensible: (1) uses sound 

scientific methods and survey methods that have been peer reviewed and tested; (2) employs 

interviewers who are trained and/or questionnaires that follow accepted guidance; (3) presents 

clear reporting and conclusions that are supported by the data; (4) studies sample populations 

that represent the population of concern and consider temporal, geographic, and cultural aspects 

of fish consumption; (5) uses current information; and (6) provides results that can be used to 

support regulatory decision making. The measures of technical defensibility are described in 

more detail at the end of this chapter.

Different surveys are designed for different purposes. This chapter reviews the design features of 

various methods for collecting information about finfish and shellfish consumption. The purpose 

of this review is to identify the specific factors that Ecology considered when evaluating fish 

consumption surveys. 

Regional-specific dietary information about people who eat finfish and shellfish is useful in 

providing a weight of evidence for evaluating the fish-consuming habits and patterns of fish 

consumers in Washington. Fish dietary information from the Pacific Northwest indicates that 

Washington State’s fish-consuming populations eat more fish than what is reflected in the rates 

used to establish regulatory standards.

To provide more information when making risk management decisions, Ecology understands

that it would be desirable to have statewide fish dietary data and information regarding the fish 

consumption habits and patterns of all Washington State fish consumers. However, in the 

absence of a statewide fish dietary survey, Ecology believes that the fish dietary information 

from Pacific Northwest fish-consuming populations such as tribal populations is useful and 

relevant for making sound risk management decisions that protect Washington State’s residents. 

Ecology believes that there is sufficient credible fish dietary information to provide fish 

consumption estimates for fish-consuming populations in Washington State. If the assumption is 

made that the fish consumption habits and patterns among the Washington State general fishconsuming population are similar to those of the U.S. general population of fish consumers, then 
Chapter 3: Methodology for Assessing 

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the fish dietary estimates for the U.S. general population may be used to provide estimates for 

the Washington general population. Ecology notes that differences between the Washington 

population and the U.S. general population do exist: for example, status as a coastal state has the 

possibility of affecting fish consumption patterns. 

The Pacific Northwest surveys have all followed a similar design: dietary recall complemented 

by food frequency questionnaires; they have been scientifically peer-reviewed (CRITFC, 2012;

University of Washington, 2012), and have included reviews of study design and analysis of the 

results of the dietary surveys. The surveys have been considered and utilized by EPA on both a 

regional and national basis for environmental regulation as well as by the State of Oregon. These 

fish dietary surveys, together with other dietary information, provide a reasonable and 

technically sound basis to estimate the fish consumption habits and patterns for Washington 

State fish consumers.

This chapter is organized into three sections:

 Surveys and other approaches used to estimate fish consumption. This section reviews 

the various methods that have been used or are available for collecting data about dietary 

habits and patterns surrounding fish consumption.

 Factors to consider when evaluating survey results. This section identifies key design or 

implementation features that impact the quality of individual surveys. 

 Establishing technical defensibility. This section describes the methodology Ecology 

used in assessing the technical defensibility of fish consumption survey information and 

results. The methodology explained here is then applied in the next chapter to surveys 

pertinent to Washington. 

3.2 Surveys and other approaches used to estimate 

fish consumption 

The various approaches to collecting information on finfish/shellfish dietary habits and patterns

include telephone surveys, mail surveys, food diaries, personal interviews, and creel surveys

(U.S. EPA, 1992). Each method has certain limitations, including bias, error, and variability

(U.S. EPA, 1992; Moya et al., 2008). Ecology thoroughly examined the methodology used in 

fish consumption surveys. To determine quality and ensure utility for each survey examined, 

Ecology evaluated experimental design, target population, sample size, location, and potential 

bias (Ecology, 1999). This analysis aids general understanding and identifies the limitations and 

utility of the available data.

Fish dietary survey methodologies and limitations, as described in this report, are consistent with 

EPA guidance for conducting fish consumption surveys (U.S. EPA, 1992, 1998). Another 

approach, a dietary market basket survey, is used by EPA’s Office of Pesticide Programs to 
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evaluate aggregate exposure to pesticide residues in food to which consumers may be exposed. 

This is a different approach that analyzes exposure to a single chemical by multiple pathways and 

routes of exposure. Market basket surveys conducted by EPA’s Office of Pesticide Programs are 

statistically designed and executed on a single-serving basis at the point of sale to the consumer

(U.S. EPA, 2000a). 

Five fish consumption survey methods, and the strengths and weaknesses of each approach, are 

briefly described below.

3.2.1 Creel surveys

Creel surveys estimate fish consumption by interviewing anglers29 on site. Using the number of 

fish caught at a given location divided by the number of people who will consume the catch, 

creel surveys can determine a fish consumption rate (Moya, 2004). The Technical Issue Paper 

entitled Recreational Fish Consumption Rates (Ecology, 2012) provides a more detailed review 

and analysis of fish consumption rates for recreational fishers.

A number of creel surveys have been conducted in Washington. Examples are:

 Landolt, M.L., Hafer, F.R., Nevissi, A., Van Belle, G., Van Ness, K., and Rockwell, C. 

1985. Potential toxicant exposure among consumers of recreationally caught fish from 

urban embayments of Puget Sound. NOAA Technical Memorandum NOS OMA 23. 

November 1985.

 Landolt, M.L., Kalman, D.L., Nevissi, A., Van Belle, G., Van Ness, K., and Hafer, F.R. 

1987. Potential toxicant exposure among consumers of recreationally caught fish from 

urban embayments of Puget Sound. NOAA Technical Memorandum NOS OMA 33. As 

cited in Tetra Tech 1988.

 Mayfield, D.B., Robinson, S., and Simmonds, J. 2007. Survey of fish consumption 

patterns of King County (Washington) recreational anglers. Journal of Exposure Analysis 

and Environmental Epidemiology, 17:604-612.

 McCallum, M. 1985. Recreational and subsistence catch and consumption of seafood 

from three urban industrial bays of Puget Sound: Port Gardner, Elliott Bay and Sinclair 

Inlet. Washington State Division of Health, Epidemiology Section. January 1985.

 Parametrix. 2003. Results of a human use survey for shoreline areas of Lake Union, Lake 

Washington, and Lake Sammamish. Sammamish-Washington Analysis and Modeling 

Program (SWAMP). Prepared for King County Department of Natural Resources. 

September 2003.

 

29 The term fisher denotes a person who fishes for any type of seafood by any method, including finfish and shellfish. The term angler refers to 

a person who fishes with hook and line.
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 Pierce, D., Noviello, D.T., and Rogers, S.H. 1981. Commencement Bay seafood 

consumption study. Preliminary Report. Tacoma-Pierce County Health Department, 

Tacoma, Washington. December 1981.

 Price, P., Su, S., and Gray, M. 1994. The effects of sampling bias on estimates of angler 

consumption rates in creel surveys. Journal of Exposure Analysis and Environmental 

Epidemiology 4:355-371. As cited in U.S. EPA, 2011.

As with any type of survey, creel surveys have both strengths and weaknesses (see Table 9)

(U.S. EPA, 1992). 

Table 9. Strengths and Weaknesses of Creel Surveys

Strengths Weaknesses

 Can assess site-specific 

consumption rates.

 Can target specific at-risk 

populations who fish at 

contaminated sites.

 The interviewer can observe the 

participant’s fishing behaviors and 

catch as well as the condition of the 

interview site.

 Recall bias is minimized by using 

visual aids and by having the 

interviewer refer to the fish caught 

around the time of the interview as 

a reference. 

 Results can be verified by looking 

at the daily catch of the participant. 

 Response rate is high.

 More information can be gained by 

using visual aids and probing 

questions. 

 Creel surveys are routinely done for 

fishery management purposes; 

adding fish consumption questions 

to the surveys can be done with 

little added cost.

 Only a limited number and types of questions are used to minimize 

survey time.

 Language barriers may exist between participants and interviewers.

 Surveys require well-trained staff that must be monitored for quality 

control. 

 If interviews are occurring at fishing sites, answers about 

consumption are hypothetical because the fish have not yet been 

consumed. 

 Participants who fish more frequently are more likely to be 

interviewed than those who fish less frequently. a

 Survey results cannot be generalized to the entire population.

 May miss anglers if not all fishing locations and times are surveyed.

 May under- or overestimate yearly consumption if survey is not 

conducted throughout the year.

 Pilot testing for a target population is not as effective as is the case 

with personal interview surveys.

 Anglers may not be as receptive to engaging in interviews as 

preselected personal interview survey interviewees.

 Fears of contact with government officials may inhibit responses of 

minority groups.

 Anglers in the field may not be as inclined or ready to respond as 

individuals that have been contacted and readied to participate in a 

personal interview survey.

 Visual aids for unique seafood preparations are difficult to develop 

without knowledge of the target population.

 If the water body is known to have chemical contamination, rates may 

be impacted by a suppression effect (i.e., the suppression of the 

harvest and consumption of fish), and hence may not result in 

protective risk estimates or cleanup levels.

 It may difficult to know who actually consumes the fish. 

a. Moya et al., 2008.
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3.2.2 Personal interviews

Personal interviews can be used to estimate fish consumption rates by asking participants 

questions about their dietary patterns, particularly about how much fish they consume over a 

given amount of time (Table 10). A useful type of personal interview survey considers 24-hour 

dietary recall. In this type of interview, participants are asked by a trained interviewer to report 

what they ate during the previous 24 hours. Although the 24-hour dietary recall format avoids 

recall bias, the short time period of recall is unable to show consumption variation over the 

course of a year (U.S. EPA, 1992). Some survey designs have addressed this by interviewing the 

same individual multiple times or by staggering interviews of the survey population over the 

course of a year. Other personal interviews may ask a participant to provide information about 

their consumption of finfish and shellfish over longer time periods, such as 2 weeks, a month, a 

season, or a year. Examples of personal interview surveys include the Native American fish 

consumption surveys conducted for tribes residing along the Columbia River basin and 

throughout Puget Sound (see Chapter 4). 

Table 10. Strengths and Weaknesses of Personal Interviews

Strengths Weaknesses

 Can assess site-specific consumption rates.

 Can identify and get information from vulnerable subpopulations 

(those populations at a disproportionate risk) by collecting data 

from participants who are close to contaminated sites and by 

asking community agencies who should be interviewed.

 Responses can be validated and supported with information 

gathered by the interviewer.

 Literacy and language barriers are minimized by face-to-face 

interaction.

 Visual aids can be used to estimate meal size or fish species, 

reducing recall bias.

 High response rate.

 Interviewer can clarify questions for respondents.

 Possible to select a random sample that is representative of the 

population.

 Pilot testing of interview with target population is possible.

 Possible to incorporate culturally unique seafood preparations

and considerations into the dietary survey.

 Possible to tailor survey to specific groups.

 Avoids issues associated with missing fishing locations or times 

that are encountered in creel surveys.

 Only a limited number and types of 

questions are used to minimize survey 

time.

 Requires coordinated and supervised 

interviewers.

 If interviews are occurring at fishing sites, 

answers about consumption are 

hypothetical because the fish have not 

yet been consumed.

 Responses may be biased by fishing 

practices at the time the interview is 

being administered. 

 Uncertainty introduced when individuals 

are asked to recall consumption 

throughout the year.
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3.2.3 Diary surveys

Diary surveys use questionnaires, in the form of logbooks, diaries, or catch cards, to record fish 

consumption over time. Information is filled out by the participant ideally at the end of a fishing 

day or at the time of consumption, to minimize possible recall bias (Table 11). 

The Connecticut Department of Environmental Protection used diary surveys to find out about 

fish meals and portion sizes eaten by Connecticut families. The families received the surveys in 

the mail (U.S. EPA, 1992; Moya et al., 2008).

Table 11. Strengths and Weaknesses of the Diary Method

Strengths Weaknesses

 Can assess site-specific consumption rates.

 Information collected over long periods of time.

 Less expensive than personal interviews.

 Large numbers of participants possible.

 Recall bias is reduced.

 Visual aids can be used to improve accuracy of 

answers.

 Respondents must be taught how to complete the 

survey by a trained interviewer.

 Participants must be literate.

 Participants must be monitored during the study to 

maintain consistency.

 Keeping a dietary record may change a participant’s 

dietary practices.

 Participants may not maintain daily record keeping.

 Language barriers may affect how participants are 

recruited and how their diary responses are 

interpreted.

 Questionnaire design is more complicated than other 

types of surveys.

3.2.4 Telephone surveys

Telephone interview surveys estimate recent fish consumption or information about recent 

fishing trips. Answers are recorded on preprinted questionnaires (Table 12) (U.S. EPA, 1992).

Table 12. Strengths and Weaknesses of Telephone Surveys

Strengths Weaknesses

 Can assess region-specific consumption rates.

 Can target and identify specific subpopulations of 

concern.

 Less expensive and time-consuming than personal 

interviews.

 High rate of success for completion of interviews.

 Sensitive information may be obtained more easily.

 Provides immediate response to questions.

 Interviewers cannot reach people who do not have 

phones.

 Interviews are limited in scope and length.

 Difficult to verify information.

 Cannot use visual aids.

 Inability to reach people by phone may be of concern 

for low-income individuals who harvest more fish than 

more affluent people.

 Language barriers may pose limitations. 
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3.2.5 Recall mail surveys

Recall mail surveys are self-administered questionnaires used to estimate fish consumption. Most 

commonly they are used to obtain information from recreational anglers (Table 13) (U.S. EPA,

1992).

Table 13. Strengths and Weaknesses of Recall Mail Surveys

Strengths Weaknesses

 Can assess region-specific consumption rates.

 Can target and identify specific subpopulations of 

concern.

 Least expensive since no interviewers are required.

 Large numbers of respondents may be contacted 

over a large area.

 Most likely to provide honest answers.

 Complex technical data may be obtained if 

respondent takes the time to consider the questions 

and/or consult other sources.

 Survey can cover broad areas of inquiry.

 Cannot reach people without mailing addresses.

 Questions must be carefully designed to 

compensate for lack of personal interaction.

 Questions should be limited in scope and 

complexity.

 Requires substantial follow-up efforts or incentives 

to achieve reasonable response rate.

 Higher number of inaccurate and incomplete 

responses.

 May miss respondents who are illiterate, or have 

difficulty in understanding questions, or who cannot 

read the language.

3.3 Survey selection criteria

Both dietary recall interviews and creel surveys have been used in Washington in various 

contexts to estimate fish consumption rates (see Chapter 4, Table 14).

Certain criteria are useful for comparing survey methodologies, and key factors influence the 

selection of a particular survey type (U.S. EPA, 1998). These selection criteria assist in 

discriminating between different survey approaches. In addition, how different survey 

methodologies compare based on these criteria highlights the various strengths and weaknesses. 

Consistent with this approach, Ecology established key considerations for selection criteria: time 

frame, resources, target populations, subpopulations, accuracy, and harvest characteristics. 

Although many of these considerations are discussed separately, Table 14 provides a useful tool 

for comparing different survey methodologies.
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Table 14. Comparison of Five Consumption Survey Methodologies Using EPA’s 

Selection Criteria

Survey Type

Selection Criteria Telephone Mail Diary Interview Creel

Time Frame

Immediate data from respondent Yes No No Yes Yes

Resources

Interviewer burden Moderate Low Low High High

Respondent burden Low Moderate High Low Low

Relative cost Moderate Low/moderate Low High High

Target Populations/Subpopulations

Survey sample known prior to conducting 

survey

Yes/no a Yes Yes Yes/no b Yes/no c

Can be used with low literacy populations Yes No No Yes Yes

Accuracy d, e

Reliability: Potential for response reliability Moderate/high Low/moderate Low/moderate Moderate/high Moderate/high

Validity: Validity of consumption estimates Low Low/high f Moderate Moderate g Low/moderate g

Validity: Validity of species identification Low Moderate Moderate Moderate/high h High

Bias: Potential to minimize recall bias Moderate Low/high f Moderate Moderate/high h Not applicable i

Bias: Potential to minimize prestige bias Moderate Low Low Moderate Moderate

Measurement error: opportunity for 

respondent to ask for clarification Moderate/high Low Low High High

Measurement error: potential for 

respondent participation Moderate Moderate Low High High

Harvest Characteristics

Many access points Yes Yes Yes Yes/no b Yes/no j

High fishing or hunting pressure Yes/no k Yes No Yes Yes/no l

Large geographic area Yes Yes Yes Yes m No

Account for seasons and times Yes Yes Yes Yes No n

Source: U.S. EPA, 1998, Table 3, p. 3-3.

a. Yes if phone numbers are obtained after sample population has been preselected; no if random digit dialing.

b. No for interviews conducted at fish/hunting access points; yes for off-site interviews.

c. Depends on ability to estimate total site usage using random sampling of all access points.

d. Given sufficient resources, all five survey approaches can generate accurate data.

e. For minority and tribal populations a sense of trust and cultural identity between interviewer and interviewee is particularly important.

f. Dependent on the recall method employed.

g. On-site interviews result in valid catch estimates, but consumption estimates are hypothetical because they measure only the intent to 

consume. Off-site interviews result in catch and consumption estimates with potentially low validity depending on the period of recall.

h. Moderate for off-site interviews; high for on-site interviews. Administering the survey at regular intervals can reduce bias associated with the 

availability of different seafood resources throughout the year.

i. Creel surveys may minimize recall bias but the responses only represent the point of time the individual starts fishing to the time the 

individual is interviewed.

j. Yes for roving creel survey; no for access point survey.

k. Yes for random telephone numbers; no for known telephone numbers.

l. Yes for access point survey; no for roving creel survey.

m.Yes when interviewees are preselected so they can tell interviewer where they have fished.

n. A creel survey may be designed to account for seasons and times; however, creel surveys seeking to develop health protective estimates of 

fish consumption may only be conducted during high harvest time periods.
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3.4 Evaluating survey vehicles

Large differences in survey objectives combined with the high variability in fish consumption 

patterns make it difficult to make generalizations about surveys. To compare and evaluate both 

the survey vehicle (that is, the questionnaire or interview process) and the data obtained, a 

number of factors should be considered. Also, to establish whether a particular survey is 

appropriate to use, each factor needs to be evaluated and documented. Moya, 2004, and U.S. 

EPA, 1992 and 1998, identify important elements of survey design.

Also of significance is whether a survey is designed to look at short-term or long-term behaviors. 

This is especially relevant when comparing results of different surveys.

3.4.1 General survey design

Survey design is fundamental to the accuracy and success of a survey, and identifying the target 

population is important both when both choosing a survey method and effectively executing the 

survey (Table 15). The design establishes the type of information collected and the level of detail 

provided (Moya, 2004). Survey accuracy improves when the following factors are considered 

during the design phase. Ecology considered these as essential in a well-designed survey.

Table 15. Survey Design Evaluation Criteria

Criteria Description

1. Timing of 

interviews

For a survey to adequately capture fish consumption, an appropriate time frame must have 

been chosen that minimizes the effect of recall bias yet captures the dietary variations.a 

(Additional discussion on survey recall error and bias are provided in the Glossary,

Appendix D.)

2. Training of 

interviewers

Interviewers should be trained for the study protocol to avoid potential interviewer bias. 

Interviewers must adhere to the questionnaire wording and format and be culturally 

sensitive when interacting with the study participants. If possible, interviews should be 

conducted by members of the target population to avoid adverse impacts associated with 

cultural differences, language barriers, and participation refusals. a

3. Consideration of 

all fish species

The types of fish consumed can be highly variable depending on seasonal and geographic 

availability, market prices, and cultural preferences. Surveys should identify and record 

each type of fish consumed and any unique preparation methods. a

4. Identification of 

the source

If known, either the water body where the fish was caught or the purchase location (for 

example, grocery store or fish market) should be identified. To improve exposure 

assessment, both locally caught fish and store bought fish should be included in fish 

consumption rate estimates. This distinction allows the risk assessor to better account for 

regional and seasonal variations in fish consumption estimates. b

5. Random selection 

of participants, 

sample size, and 

statistical analysis

During the planning phase, statistical analysis helps identify the ideal sample size and how 

to randomly select participants. This analysis helps minimize bias and sampling error and 

ensures statistical rigor. After the data have been collected, sound descriptive statistical 

analysis should ensure that the data are presented accurately. The range of data should 

be presented with confidence intervals and appropriate distribution values. Weighting 

schemes should be clearly described in order to apply survey results to populations of 

interest. Statistical treatment of perceived outliers should be discussed. 
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Criteria Description

6. Appropriate 

quality assurance 

and quality control

The study design should include appropriate quality assurance and quality controls into the 

planning and execution of the survey. For example, types of quality control measures 

would include checking questionnaires for completeness and proper entry of recorded 

responses, verifying correct data entry, and checking the manual coding operations and 

comparisons of results and error rates. This reduces bias and random error, improving 

accuracy. c 

7. Accuracy and 

precision

The study design can affect the overall accuracy of the study. Accuracy can be split into 

five components. Reliability (the variability or repeatability of the response), validity (the 

ability of the respondent to provide the correct answer), measurement errors (which are 

associated with the interviewer, the respondent, the questionnaire, and the mode of data 

collection), bias (the consistent overestimation or underestimation due to survey design 

and sample selection), and random errors. c

Sources:

a. Ecology, 1999.

b. Ebert et al., 1994.

c. U.S. EPA, 1998.

3.4.2 Survey questions

The following information should be collected from study respondents and is necessary for 

understanding what they eat (Strauss, 2004).

30

 Frequency and quantity (how much fish is consumed per day, week, or month).

 Parts of the fish consumed.

 Species consumed.

 Source of the fish.

 Seafood preparation and cooking methods.

 Respondent’s body weight.

 Exposure duration.

 Approximate age (child or adult).

Survey questions should be clearly worded, unambiguous, and well understood to obtain clear 

and correct answers from respondents.

 

30 See this 2004 article by Strauss for details regarding complexities and variability.
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3.4.3 Population surveyed

The sample population must represent the target population. This is particularly important 

because fish consumption rates may be affected by the socio-demographic characteristics of a 

population. Furthermore, the type of survey used may influence or determine a number of things, 

including what population will respond to the survey, the response rates, and the level of detail 

obtained (Moya, 2004). 

3.4.4 Description of water body

The survey must identify and understand the characteristics of all relevant water bodies, 

including location, size, species inhabiting the water, and fish advisory status. These 

characteristics influence the quantity of fish available. In addition, this information is critical to 

producing results that can be used to compare with or extrapolate to other populations (Moya, 

2004).

3.4.5 Survey results

Ecology considered it important to evaluate how the survey results are presented and what they 

are meant to represent. This included identifying and considering goals of the survey. 

Estimating the size of a meal is subject to error, especially when a survey vehicle (questionnaire 

or interview) does not include visual aids. Also, quantities of seafood may be part of stews, 

soups, and other recipes that may or may not be accounted for in fish dietary survey design.

Sound descriptive statistical analysis is required to ensure that the data are presented accurately. 

The range of data should be presented with confidence intervals and appropriate distribution 

values (Moya, 2004). Weighting schemes should be clearly described in order to apply survey 

results to populations of interest. Statistical treatment of perceived outliers should be discussed. 

3.4.6 Factors to consider

Ecology identified the following factors as appropriate and necessary when evaluating survey results:

 Cultural factors. Does the population group of interest (for example, Native Americans 

or Asian and Pacific Islanders) have cultural characteristics that should be considered 

when designing a fish consumption survey? Native American ways of life may influence 

fish consumption habits and patterns; salmon is of particular significance in the diet of 

Northwest Pacific Native American tribal peoples. Asian and Pacific Islanders may 

consume parts of organisms that differ from those preferred by other populations. Also, is 

the survey designed to identify subsistence fishing practices? 
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 Fish diet fraction (the portion of fish consumed that comes from the site). Have sources of 

fish tissue contamination been considered in the design and/or evaluation of the survey? 

Are the fish consumed harvested from local waters? Does the survey distinguish between 

store-bought fish or fish consumed in restaurants and fish harvested from local waters?

 Types of seafood (finfish and shellfish) consumed from marine, freshwater, and estuarine 

habitats. This information may be useful in characterizing risks for consumption of 

aquatic biota that have different contaminant levels as a result of their feeding behaviors 

(for example, bottom feeding fish or top predator species). Has the fish consumption 

survey considered both the range of types of finfish/shellfish consumed and where they 

are harvested?

 Cooking methods. Use of cooked weights or uncooked weights to measure fish consumed 

must be standardized. Generally, uncooked weights are preferred because environmental 

contaminants are usually analytically determined for wet weight. Cooking fish can reduce

the weight of a fillet by 20 percent or more (U.S. EPA, 1998). Have the methods of food 

preparation and cooking been considered in the fish consumption survey design and/or 

evaluating the survey?

 Are there historical and traditional fishing areas and practices that should be identified?

 Environmental justice. How have historically underrepresented populations and 

disproportionately impacted communities been considered in the design and evaluation of 

fish consumption surveys? 

3.5 Measures of technical defensibility 

For purposes of this report, Ecology developed several measures of technical defensibility to help 

guide the evaluation of individual surveys. These measures of technical defensibility ensure that 

a survey can stand up to technical and scientific scrutiny and are described in Table 16. They

represent an expansion of the two selection criterion used by the June 2008 Oregon Human 

Health Focus Group-Oregon Fish and Shellfish Consumption Rate Project 

Collectively, these measures of technical defensibility provide an assessment of overall technical 

suitability to support regulatory decision making (for example, they provide information about

whether the survey results are suitable and appropriate in a regulatory context for establishing 

risk-based standards).
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The measures of technical defensibility are based on:

 EPA Exposure Factors Handbook, 2009 Update (U.S. EPA, 2009a).

 EPA Exposure Factors Handbook, 2011 Edition (U.S. EPA, 2011a).

 EPA Guidance for Conducting Fish and Wildlife Consumption Surveys (U.S. EPA, 1992, 

1998).

 Consultations with the University of Washington, Environmental and Occupational 

Health Sciences.

31

Ecology applied these measures of technical defensibility to selected fish dietary surveys 

performed in Washington State. Ecology has not applied these measures of technical 

defensibility to all surveys conducted in Washington; many of these surveys were conducted for 

specific water bodies to help support fish advisories, or were used to assess risks to specific 

ethnic populations. 

Water body-specific fish dietary surveys are limited in scope because they evaluate very specific 

populations, usually recreational anglers and specific ethnic groups, which harvest and consume 

fish from a particular water body within a specific county or jurisdiction in Washington State. 

Each serves a useful purpose to help evaluate and assess potential health risks from consuming 

contaminated finfish and shellfish; however, their methodology does not allow for the projection 

of longer term estimates of fish consumption. 

The additional fish dietary information provided in Table 32 and Appendix B, although not 

meeting the measures of technical defensibility described in this chapter, provides support, using 

a weight-of-evidence approach, to the idea that people in Washington State harvest and consume 

considerable amounts of fish. 

 

31 Ecology acknowledges input from the University of Washington, Seattle, Environmental and Occupational Health Sciences and Departments

of Medicine and Internal Medicine.
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Table 16. Measures of Technical Defensibility

Measure Description

1. Survey Method 

Development

 Was the survey design based on sound scientific survey methods recognized 

either in guidance or other technical publications?

 For surveys dealing with unique populations (for example, tribes or ethnic 

minorities), was the survey vehicle reviewed by tribal staff and tribal 

governments? Did it include review and collaboration with state and federal 

agencies?

 Was the survey tested and modified before it was conducted? 

 Did the survey design evaluate the essential elements provided in Table 15?

2. Survey Execution  Was the execution of the survey based on sound survey methods recognized 

either in guidance or other technical publications?

 Were the personnel conducting interviews provided adequate training?

 Were finfish/shellfish models used as visual aids to help participants estimate 

approximate amounts and types of fish consumed? 

3. Publication of 

Results

 Was the publication of survey results based on sound survey methods recognized 

either in guidance or other technical publications?

 Was the study methodology clearly defined and reported?

 Is there a discussion of the consistency of the survey’s methodology with 

accepted practices?

 Was the study methodology consistent with sound survey practices?

 Were the survey results tabulated and reported clearly?

 Were statistical approaches (including weighting and treatment of outliers) clearly 

explained?

 Were the study conclusions clearly reported and supported by study findings?

 Were variability and uncertainty recognized? 

 Were uncertainties identified and reported? 

 Did the survey design take into account and/or discuss factors that might 

contribute to bias in the study results?

4. Applicability and 

Utility for Regulatory 

Decision Making

 Is the sample population representative of the population of concern, and does 

the survey provide sufficient information about the sample population to 

characterize the population being studied?

 Is it reasonable to apply the results of the surveyed population to populations of 

concern?

 Are the water bodies/fisheries resources upon which the surveyed population 

relies similar to the water bodies being regulated?

 Is the information current and is suppression effects on fish dietary habits 

recognized and accounted for?

 Are fish consumption rate statistics commonly used for regulatory purposes 

presented and supported?

 Are data sufficient for descriptive statistics to define statistical fish consumption 

rate distributions?
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3.6 Custody of fish dietary survey data

Most fish dietary surveys that address the habits and patterns of ethnic groups (Asian and Pacific 

Islanders, Native American populations) are funded either through state or federal cooperative 

agreements or grants. Survey questionnaires are generally developed in close collaboration with 

an organization that represents the ethnic group or technical personnel associated with the tribal 

governments or tribal natural resource offices. Surveys are conducted by trained tribal personnel 

or people representative of the ethnic population being surveyed. The resulting data may be 

owned by the tribal government or the ethnic group that collaborated on the survey. The survey 

design and methodology are generally reviewed by the funding organization (federal or state) 

and technical personnel or representatives from the tribe or ethnic group.

The custody of survey data by tribal governments is related to their concerns with maintaining and 

sustaining tribal sovereignty and honoring confidentiality agreements with individual participants 

surveyed. The tribal governments have employed various methods to establish data quality without 

releasing individual response data to entities other than tribal governments. Ecology acknowledges 

that further evaluations would be possible using individual level response data. 

Pacific Northwest Native American fish consumption surveys are designed and executed as 

government-to-government collaboration with state and federal governments. They are generally 

published under the authority of the tribal governments. 

There are a number of ways to establish the defensibility of data. Scientific journals use peer 

review to establish scientific defensibility of reported results. A recent Science Magazine

editorial (Hanson et al., 2011) noted the importance of making data available for scrutiny so that 

other researchers can verify results and test conclusions. Using independent statisticians for 

review and analysis may circumvent the need to release the raw data.

Many Pacific Northwest tribal organizations or tribal governments do not provide their raw seafood 

dietary data to researchers outside of their sovereign tribal government or organizations. They may 

consider survey data as confidential and not allow independent evaluations. Data evaluation 

typically occurs through government-to-government agreements or tribal technical personnel. 

For example, the fish consumption survey of the four tribes that reside throughout the Columbia 

River basin was initiated through a cooperative agreement between EPA and the CRITFC. The 

development, design, and execution of the CRITFC fish consumption survey vehicle were 

conducted through the respective tribal governments that compose CRITFC. The fish 

consumption data were collected and evaluated by tribal members and technical staff and are

retained by CRITFC. Other Pacific Northwest Indian tribes follow a similar pattern where the 

data are retained by tribal governments or Pacific Northwest Indian commissions.
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Ecology evaluated the Native American fish consumption surveys, as well as other available 

surveys conducted in the Pacific Northwest, based on the measures of technical defensibility 

discussed above. That evaluation is described in the following chapter.
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Chapter 4: Fish Consumption Survey Data 

that Apply to Washington Fish Consumers

4.1 Introduction

Over the last several years, Ecology has evaluated available fish consumption surveys to support 

site-specific regulatory decisions. 

Fish consumption survey data are identified, discussed, and evaluated against the measures of 

technical defensibility presented in Chapter 3. The purpose of this chapter is to identify those 

surveys that are most appropriate for assessing fish consumption rates in Washington. A word of 

caution is appropriate. Many sources of data are available and provide information that may be 

appropriate for answering particular questions. The question being considered in this chapter is 

identification of data appropriate for use in a regulatory context to characterize fish-consuming 

populations across Washington State.

Ecology considered a range of information that describes fish consumption rates and patterns for 

fish consumers in Washington. In general, Ecology examined: 

 General population surveys conducted at the national level.

 Dietary surveys of Washington Native American populations.

 A dietary survey of Asian and Pacific Islander populations in King County. 

 Washington water body-specific evaluations, assessments, or health advisories issued by 

DOH.32

 Technical publications, assessments, and/or evaluations of fish consumption specific to 

the Pacific Northwest.

 Various evaluations or assessments used to make regulatory decisions. For example, the 

baseline human health risk assessment performed for the Lower Duwamish Waterway,

which refers to the EPA Region 10 Framework and Kissinger re-evaluation (Windward 

Environmental, 2007; U.S. EPA, 2007b; Kissinger, 2005).

33

 

32 Washington State Department of Health fish consumption advisories by water body located at the following web link: 

http://www.doh.wa.gov/CommunityandEnvironment/Food/Fish/Advisories.aspx, and Port Angeles: http://www.ecy.wa.gov/news/2012/052.html

33 Besides the Lower Duwamish Waterway Remedial Investigation Report, Ecology also considered the Port Angeles and Port Gamble 

sediment cleanup:

Port Angeles: http://www.ecy.wa.gov/programs/tcp/sites_brochure/portAngelesHarborSed/paSed_hp.htm

Port Gamble: http://www.ecy.wa.gov/programs/tcp/sites_brochure/psi/portGamble/psi_portGamble.html
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These data were examined and assessed to identify technically defensible studies appropriate for 

use in characterizing fish-consuming populations in Washington. 

To provide a more detailed look at fish consumption patterns across the state, where possible, 

fish consumption data and descriptive statistics have been tabulated for both locally harvested 

fish, and for fish consumed from all sources including stores and restaurants. Where available, 

additional fish consumption estimates from Pacific Northwest fish dietary surveys are included 

for groups of fish species, such as finfish, shellfish, anadromous finish, and non-anadromous 

finfish. 

4.2 General population data

Currently, there are no fish dietary data available for the general fish-consuming populations in 

Washington State. That is, there is not a survey of fish consumption of the entire population of 

Washington State. Ecology examined information on fish consumption among the U.S. national 

general population.

Ecology notes that national data show that people who live in coastal areas consume fish at 

higher rates than those living in other areas (Moya, 2004) and that EPA recommends using 

regional-specific data, when available (U.S. EPA, 2000b, 2007b, 2011a). 

4.2.1 Continuing Survey of Food Intakes by Individuals

In 2000, the EPA developed national estimates of fish consumption based on an analysis of the 

U.S. Department of Agriculture’s (USDA) 1994–1996 Continuing Survey of Food Intakes by 

Individuals (CSFII) and its 1998 Children’s Supplement (U.S. EPA, 2002a). (These USDA 

reports are collectively referred to as CSFII 1994–1996, 1998).

The USDA surveys were designed to provide estimates of food consumption across the United 

States and were conducted in all 50 states and Washington, D.C. They include fish consumers 

and non-consumers, and provide data for federal activities related to the nutritional status of the 

U.S. population.34 The national fish dietary information is not representative of some 

Washington State fish-consuming populations, such as Asian-Pacific Islanders and Native 

Americans.

Over 20,000 survey participants each provided dietary information during two non-consecutive 

24-hour periods. The survey was designed so that the second interview occurred 3 to 10 days 

after the first interview but not on the same day of the week. The dietary recall surveys were 

administered over a period of 4 years.

 

34 By definition, per capita fish consumption includes consumers and non-consumers of fish. The per capita survey methodology is different 

than the Pacific Northwest fish dietary recall studies and is discussed below.
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The CSFII was conducted by interviewing respondents according to a stratified design that 

accounted for geographic location, degree of urbanization, and socioeconomics. Eligibility for 

the survey was limited to households with gross incomes at or less than 130 percent of the 

federal poverty guidelines. Survey weights were assigned to this dataset to make it representative 

of the U.S. population. 

The CSFII is the primary source of food consumption data used in dietary risk assessments. It is 

well suited to national-level dietary risk assessments, because it is statistically designed to 

sample individuals of all ages and major ethnic subgroups to reflect various demographics. The 

CSFII is statistically designed so that the national estimate of consumption is not biased by 

seasons of the year or regions of the country (U.S. EPA, 2001). The CSFII may be considered a 

variation of the dietary market basket survey approach but on a larger-scale with a more 

sophisticated design and execution. 

Ecology notes, however, that the survey methodology limits its use. In particular, participants 

who did not eat fish on either of the two days surveyed would be considered non-consumers. The 

rate of fish consumption (or non-consumption) for individual consumers during the two days 

surveyed was assumed to represent their consumption rate for the entire year. In other words, 

someone who did not eat fish during the two days of the survey was assumed to consume no fish 

at all during the year. The resulting values may not be representative of long-term consumption 

rates that have been averaged over time and presented as a daily rate. 

By definition, per capita fish consumption rates reflect fish dietary habits averaged over the 

general U.S. population, including people who never eat fish. Hence, per capita fish consumption 

rates do not necessarily describe actual fish consumption by consumers of finfish and shellfish. 

Although fish consumption rates derived for consumers would be preferable to per capita rates in 

describing the consumption of finfish and shellfish in the United States, there are limitations 

when “consumer only” rates are derived from national per capita surveys: 

 During the two non-consecutive days of the survey period, the amount of fish and 

shellfish that a respondent ate on a given day would not be equivalent to the gram per day 

value obtained when the amount of fish consumed over a longer survey period is divided 

by the number of survey-period days for a more comprehensive fish dietary recall survey.

 People who typically consume finfish and shellfish, but did not do so during one of the 

two non-consecutive days of the survey period, were not captured by the survey and

therefore are not included in national fish consumption estimates for consumers. 

 It is not possible to determine the percentage of the finfish- and shellfish-consuming 

population that was missed, or whether the respondents who did consume finfish or 

shellfish during the survey’s two-non-consecutive-day reporting period are adequately 

representative of the U.S. fish-consuming population. 
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Ecology acknowledges the difficulty in evaluating the data from the EPA 2002 per capita 

estimates. We have considered this information in helping to estimate the number of fish 

consumers in Washington but not in estimating a fish consumption rate. We have also used the 

per capita data to define high fish consumers in order to approximate the number of high fish 

consumers among the general population. 

Table 17. General Population: Adult Respondents, Consumers Only, Based on 

CSFII 1994 to 1996

Population

Number of 

Adults 

Surveyed

Descriptive Statistics (g/day)

Mean Median Percentiles

75th 90th 95th 99th

U.S General Population

(consumers only) 2585 127 99 - 248 334 519

Source: Adapted from Oregon DEQ, 2008, Table 3, based on EPA 2002 and CSFII dietary data. Persons interested in further details on the 

CSFII are referred to U.S. EPA, 2002.

4.2.2 National Health and Nutrition Examination Survey, 2003 to 

2006

The EPA 2011 national estimates for fish consumption are based on analysis of the USDA 

National Health and Nutrition Examination Survey (NHANES) from 2003 to 2006. The fish 

consumption estimates from the NHANES 2003–2006 data are available in Chapter 10 of EPA’s 

Exposure Factors Handbook, 2011 (U.S. EPA, 2011a). 

Designed to assess the health and nutritional status of adults and children in the United States, 

starting in 1999, NHANES is a continuous program that interviews nationally representative 

samples of about 7,000 people annually. The survey is administered for two non-consecutive 24-

hour periods of dietary intake. Data for the first day is collected in-person, while data for the 

second day is collected by telephone about 3 to 10 days later. Using the 2000 U.S. population 

census estimates to develop the sampling frame, the NHANES 2003–2006 surveys are 

probability-based and county-based population samples from across the United States. 

The EPA’s Office of Pesticide Programs used NHANES 2003–2006 data to update the CSFII 

1994–1996, 1998 study (as presented in EPA’s 2002 Estimated Per Capita Fish Consumption in 

the United States). Summary statistics were developed for fish consumers only and on a per 

capita basis. Dietary rates were derived for finfish, shellfish, and finfish and shellfish combined 

(shown for consumers only in Table 18 and Figure 1 below). Two-day average dietary fish 

consumption rates were calculated for all respondents who provided dietary information for two 

days of the survey. If a respondent reported consuming fish on one of the two days of the survey, 

then their 2-day average would be half the amount reported for the one day of consumption. 

The EPA 2011 Exposure Factors Handbook (U.S. EPA, 2011a, p. 10–16) qualifies the fish 

dietary estimates as follows:
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...it should be noted that the distribution of average daily intake rates generated using 

short-term data (e.g., 2-day) does not necessarily reflect the long-term distribution of 

average daily intake rates. The distributions generated from short-term and long-term 

data will differ to the extent that each individual’s intake varies from day to day...

...Short-term consumption data may not accurately reflect long-term eating patterns and 

may under-represent infrequent consumers of a given fish species. This is particularly 

true for the tails (extremes) of the distribution of food intake.

Table 18. General Population: Adult Respondents, Consumers Only, Based on 

NHANES 2003–2006, Using Standard Statistical Survey Methodology

Population Species 

Group

Descriptive Statistics (g/day)

50th Percentile Mean 75th

Percentile

90th

Percentile

95th

Percentile

National 

Estimates from 

NHANES 

2003–2006

(consumers only)

All Fish 37.9 56.0 78.8 128 168

Finfish 34.6 49.9 68.9 115 150

Shellfish 25.7 43.0 54.4 101 147

See Polissar et al., 2012. Estimates based on statistical methodology defining fish consumers as those who consumed fish on at least one of 

the two dietary recall days.

Ecology reevaluated the NHANES fish dietary data using the National Cancer Institute’s (NCI) 

statistical methodology (Polissar et al., 2012). The NCI method estimates usual intake of 

episodically consumed foods by accounting for day-to-day variations (Tooze et al., 2006). The 

national dietary information (CSFII and NHANES) consists of two detailed 24-hour dietary 

recalls conducted for a large, randomly selected U.S. population. Although 24-hour dietary recall 

surveys capture detailed information on a person’s food consumption, this dietary assessment 

method does not adequately measure the usual intake of foods that are not consumed nearly 

every day (i.e., episodically consumed foods such as fish). The NCI method uses statistical 

modeling to combine food frequency questionnaire data with 24-hour dietary recall data to 

project long-term food consumption estimates. Results are shown in Table 19 and Figure 2

below.
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Table 19. General Population: Adult Respondents, Consumers Only, Based on 

NHANES 2003–2006, Using NCI Statistical Survey Methodology

Population Species 

Group

Descriptive Statistics (g/day)

50th Percentile Mean 75th

Percentile

90th

Percentile

95th

Percentile

National 

Estimates from 

NHANES 

2003–2006

(consumers only)

All Fish 12.7 18.8 24.8 43.3 56.6

Finfish 9.0 14.0 18.1 31.8 43.3

Shellfish 2.4 5.4 6.0 13.2 20.5

See Polissar et al., 2012. Estimates based on NCI statistical methodology (Tooze et al., 2006) that models two days of fish consumption from 

24-hour episodic dietary recall and fish dietary information from the food frequency questionnaire.

Figure 1. General Population Adult Fish Consumption Rates, Consumers Only, 

NHANES 2003–2006, Using Standard Statistical Survey Methodology

54.4

68.9

78.8

147

150

168

0 20 40 60 80 100 120 140 160 180

Shellfish

Finfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 18)
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Figure 2. General Population Adult Fish Consumption Rates, Consumers Only, 

NHANES 2003–2006, Using NCI Statistical Survey Methodology

Technical defensibility

As summarized in Table 20 below, Ecology has determined that the national surveys of the 

general population are relevant to Washington and satisfy measures of technical defensibility. 

Table 20. Technical Defensibility of National (General Population) Fish Dietary 

Information

Metric Observations and Comments Evaluation

1. Survey Method Development

Description of survey vehicle Survey methodology and analysis of 

survey data independently conducted by 

two federal agencies

Survey methodology, design 

and analysis described in detail; 

sample size very large to 

provide good dietary information 

for the general U.S. population

Description of sample population Large sample size, randomly selected, 

and sample geographically representative 

of national general population

2. Survey execution

Survey method Survey data based on recent 2-day 

dietary recall; data collected over short 

duration and independent collection 

periods

Nationwide survey with sample 

selection based on randomized 

selection; two non-consecutiveday recall supports 

development of per capita 

consumption estimates; high 

level of peer review on 

methodology design and 

execution

Bias Good response rate (> 70%)

Review and evaluations Quality assurance/quality control (QA/QC)

standards are high and documented

Review and evaluations National Center for Health Statistics

6

18.1

24.8

20.5

43.3

56.6

0 20 40 60 80 100 120 140 160 180

Shellfish

Finfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 19)
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Metric Observations and Comments Evaluation

3. Publication of results

Where published and clear 

information

Published by USDA, EPA, and other 

agencies 

Accessible through large number 

of venues and publications

Survey methodology Two non-consecutive-day dietary recall 

Applicability for regulatory decision making

Currency of information CSFII 1994–1996 and 1998

2003–2006 NHANES

Suitable for average intake rates 

of general population; not 

intended to substitute for regionalspecific fish dietary information a

Representative of target population Representative of the general U.S. 

population

4. Overall technical suitability for regulatory decision making

Range of technical defensibility Survey method designed to provide 

average intake rates for general populations

Not designed to capture longterm dietary intake

Appropriateness for use in riskbased standardsDesigned to provide average dietary 

intake rates 

Not a substitute for regionalspecific dietary information

Sources: U.S. EPA, 2011a; USDA CSFII 1994–1996, 1998.

a. Study design may bias high upper percentile consumer only fish consumption estimate; however, use of national fish dietary information 

underestimates fish consumption estimates for areas with more fisheries and resources (i.e., Washington State).

4.3 Pacific Northwest Native American fish 

consumption data

As of the writing of this report, results of three tribal-specific finfish/shellfish dietary surveys of

tribes along the Columbia River basin and in the Puget Sound area of Washington were available 

for review. 

In addition, several technical publications provide information on tribal fish consumption

(Harper et al., 2002, p. 513–526; Harris and Harper, 1997, 2001). These publications have been 

used to define a tribal reasonable maximum exposure (RME) for various regulatory decisions.

35

Although these technical publications provide useful information for specific regulatory 

decisions, it is the published tribal fish consumption surveys that provide the relevant

information on fish consumption. The surveys employed a well-defined, standardized, dietary 

survey methodology, data analysis, and reporting of results. 

Tribal fish dietary surveys provide relevant fish dietary information for Washington State fish 

consumers because these surveys include: (1) respondents that are fish consumers from 

Washington State; (2) locally harvested and consumed finfish and shellfish; (3) well-defined,

standardized, dietary survey methodology, data analysis, defined measures of quality assurance 

and quality control, and reporting of results; (4) close collaboration with and support from 

academia and state and federal health and resource agencies; (5) minimized recall bias in the 

 

35 In Harper et al., 2002, Table 11, p. 521 notes 885 – 1,000 g/day for those with a high fish diet (fish consumers) and 175 g/day for shellfish 

consumption for fish consumers and non-consumers of fish.
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surveys due to dietary and culturally based dependence on fish consumption; and (6) the wellsupported assumption that locally harvested fish includes fish from large freshwater, estuarine,

and marine water areas of Washington State because tribal reserved rights include harvesting fish 

and consuming fish from all watersheds throughout the state.

Ecology reviewed and analyzed the data from these surveys, looking specifically at species 

consumed and where the fish were obtained (Polissar et al., 2012). The fish dietary surveys 

provide credible information on the types and amounts of fish consumed by Native American 

populations in Washington State. Generally, the fish dietary surveys indicate that these 

populations consume large amounts of finfish and shellfish harvested from marine and 

freshwater environments throughout Washington.

This section describes the surveys, along with an evaluation of technical defensibility.

4.3.1 Columbia River Inter-Tribal Fish Commission survey: the 

Umatilla, Nez Perce, Yakama, and Warm Springs Tribes of the 

Columbia River Basin 

The Columbia River Inter-Tribal Fish Commission (CRITFC) surveyed fish consumption among 

four Native American tribes that reside along the Columbia River basin (CRITFC, 1994). The 

survey of adult tribal members who lived on or near the Yakama, Warm Springs, Umatilla, or 

Nez Perce Reservations was conducted during the fall and winter of 1991–1992.

36

The survey identified individual tribal members’ consumption rates, habits, and food preparation 

methods for anadromous and resident fish species caught from the Columbia River basin. A 

random sampling was taken based on respondents selected from patient registration files of the 

Indian Health Service. The survey questionnaire included a 24-hour dietary recall and questions 

regarding seasonal and annual fish consumption. Food models were used to help respondents 

estimate the amounts of fish consumed.

Information obtained included age-specific fish consumption rates, the fish species and parts of 

the fish consumed, and the methods used to prepare the fish for consumption. 

Personal interviews conducted on the four tribal reservations achieved an overall response rate of 

69 percent from a sample size of 513 tribal members 18 years of age or older. Tribal adult 

respondents provided information for 204 children 5 years of age or younger. Since tribal 

population sizes were unequal, demographic weighting factors were applied to the pooled data in 

proportion to tribal population size, so that survey results would reflect the overall population of 

adult members of the four tribes. An unweighted analysis was performed for children, since the 

sample size was small. To derive consumption rates that represented the adult tribal population 

as a whole, the survey averaged the fish consumption for both consumers and non-consumers. 

 

36 As noted in the survey, conducting interviews over this period of time biased the consumption estimates low because of low availability of fish 

to harvest during that seasonal period of time.
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All interviews were conducted at tribal offices, which could potentially select against individuals 

with mobility problems. It is possible that tribal elders, who may be more likely to practice 

subsistence consumption, were omitted from the survey. Since adults answered questions 

regarding children’s fish consumption, the adult respondents may have mistakenly answered 

questions as if they were providing their own survey responses. Selected outliers were removed 

from the datasets. 

CRITFC consumption rates represent consumption from all sources. Salmon and steelhead were 

consumed by the largest number of adult respondents, followed by trout, lamprey, and smelt. A 

seasonal variation in fish consumption was observed, with the most fish consumed April through 

July. The mean fish consumption rate was 108 g/day. There was a large seasonal variation in fish 

consumption. The reported mean rate of consumption during the high months (April–July) was 

three times the mean rate of consumption in low months (November–February). 

The mean fish consumption rate for all surveyed tribal adults (consumers and non-consumers) 

throughout the year was 58.7 g/day. Seven percent of survey respondents did not consume fish. 

Excluding non-consumers of fish, the mean fish consumption rate for surveyed tribal adult fish 

consumers was 63.2 g/day. The average consumption rate for children (5 years old and younger) 

was 24.8 g/day. About 83 percent of the 204 children consumed fish. The 99th percentile fish 

consumption rates of adults and children (5 and younger) who consume fish were 389 g/day and 

162 g/day, respectively. 

Reanalysis of the CRITFC survey report by Ecology provides estimates of anadromous, nonanadromous, all finfish consumption estimates, and source of harvest (Table 21, Figures 3 and 4). 

Slight variations between can be attributed to procedures used to estimate rates and percentiles 

(Polissar et al., 2012).

Table 21. CRITFC Adult Fish Consumption Rates by Species Group and Source, 

Consumers Only

Population

Tribal Species Group

Harvest 

Source of

Fish

Descriptive Statistics (g/day)

50th

Percentile Mean 75thPercentile

90th

Percentile

95th

Percentile

The 4 Tribes 

Affiliated 

With The 

Columbia 

River InterTribal Fish 

Commission

All finfish all 40.5 63.2 64.8 130.0 194.0

Non-anadromous all 20.9 32.6 33.4 67.0 99.9

Anadromous all 19.6 30.6 31.4 63.1 94.1

All finfish Columbia 

River Basin 35.6 55.6 57.0 114 171

Non-anadromous Columbia 

River Basin 18.4 28.6 29.4 58.9 87.9

Anadromous Columbia 

River Basin 17.3 27.0 27.7 55.5 82.8

See Polissar et al., 2012, Table E-1.
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Figure 3. CRITFC Adult Fish Consumption Rates, Harvested from All Sources

Figure 4. CRITFC Adult Fish Consumption Rates, Harvested from Columbia 

River Basin

31.4

33.4

64.8

94.1

99.9

194

0 50 100 150 200 250 300

Anadromous

Non-Anadromous

All Finfish 

grams/day

95th %ile

90th %ile

75th %ile

Mean

27.7

29.4

57

82.2

87.9

171

0 50 100 150 200 250 300

Anadromous

Non-Anadromous

All Finfish 

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 21)

(See Table 21)
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Technical defensibility

As summarized in Table 22 below, Ecology has determined that the 1994 CRITFC survey is 

relevant to Washington and satisfies measures of technical defensibility. 

Table 22. Columbia River Inter-Tribal Fish Commission Consumption Survey

Metric Observations and Comments Evaluation

1. Survey Method Development

a. Type and description of 

survey vehicle

24-hour and seasonal dietary recall personal interview survey; 

respondents were randomly selected from Indian Health Service 

records; a large range of fish was considered in the survey (salmon, 

lamprey, smelt.) 

The survey method 

and vehicle were 

developed in a 

technically defensible 

b. Collaboration and manner. 

review 

CRITFC staff developed the survey in collaboration with Washington

DOH, EPA HQ & Region 10 staff, Indian Health Service staff; it was 

reviewed by tribal governments of the CRITFC member tribes (Nez 

Perce Tribe, Confederated Tribes and Bands of the Yakama Indian 

Nation, Confederated Tribes of the Warm Springs and Umatilla Indian 

Reservations).

c. Beta testing The survey was tested by tribal staff in consultation with EPA.

2. Survey execution

a. Establish and document 

execution standards

Execution of survey vehicle by native population documented; data 

gathered on adult respondents 18 years or older and children 5 years 

or younger.

The survey vehicle 

was appropriately 

executed and 

documented; use of 

fish models was 

documented.

b. Document staff training Native staff trained personnel in collaboration with and with technical 

oversight provided by state/federal agencies.

c. Finish/shellfish models 

used

Fish models were employed to aid in identifying the amount of finfish 

and shellfish consumed.

3. Publication of results

a. Where were results 

published? Are they 

clear and complete?

Results were published in a CRITFC tribal government publication. 

The population surveyed, method used, conclusions, and tabulations 

were well-defined, presented, and documented. The highest fish 

consumers were considered outliers and were dropped from the 

survey data and, therefore, were not statistically evaluated.

The data presented 

are sufficient to 

develop consumption 

distributions with 

percentiles.

b. Methodology reported The methodology used is clearly described and documented.

c. Results tabulated and 

stated

Survey results are reported and summarized in a tabular format 

suitable for distributional descriptive statistics; the report documents 

an acceptable response rate (69%).

d. Conclusions clearly 

reported

Conclusions are stated and correspond to data tabulated.

e. Variability and 

uncertainty 

Variability and uncertainty were qualitatively recognized and noted.

f. How is the potential for 

bias addressed?

Different types of bias were identified and discussed in the survey.

4. Applicability and utility for regulatory decision making

a. Representation of target 

population 

The survey provides a reasonable estimate of fish consumption for 

CRITFC member Native populations within the Columbia River Basin 

(Nez Perce Tribe, Confederated Tribes and Bands of the Yakama 

Indian Nation, Confederated Tribes of the Warm Springs & Umatilla 

Indian Reservations).

This survey meets 

the standards of 

relevance, 

applicability, and 

utility and is 

appropriate for use in 

regulatory decision 

making. Rigorous 

review of survey 

design, execution, 

data analysis, and

conclusions.

b. Currency of information Surveys were conducted in the early to mid-1990s; more recently, the 

CRITFC estimates were used by Oregon DEQ for developing water 

quality standards (2011).
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Metric Observations and Comments Evaluation

c. Sufficiency of data The fish consumption estimates are sufficient to provide descriptive 

statistics for defined distributions and percentiles for risk-based 

decision making. However, it is unclear what portion of seafood 

consumed is harvested from local sources. CRITFC fish consumption 

rates are for seafood from all sources and include anadromous 

(migratory) species.

5. Overall technical suitability for regulatory decision making

a. Range of technical 

defensibility

Survey design, development of methodology, execution of survey, 

data interpretation, and conclusions for fish consumption provide a 

reasonable quantitative exposure estimate of fish consumption rates 

for target populations. 

Ecology concludes 

survey is technically 

defensible. 

b. Appropriateness for use 

in risk-based standards

The data are sufficient to provide distribution, average, and percentile 

estimates of fish consumption as required for risk-based decision 

making.

Source: CRITFC, 1994.

The CRITFC fish dietary survey was one of the first tribal dietary surveys conducted in the 

Pacific Northwest. The technical rigor applied to the design and conduct of this survey has been

mirrored by other regional-specific surveys conducted in Washington State. The March 19, 2012, 

correspondence from Babtist Paul Lumley, Executive Director of CRITFC, to Ted Sturdevant, 

Director, Washington State Department of Ecology, summarizes the efforts that support the 

scientific defensibility of the CRITFC fish dietary survey (CRITFC, 2012). As described in this 

correspondence, the salient features of the 1994 CRITFC survey design and analysis are 

provided below:

 A technical panel was established to assist in designing and implementing the survey. 

The panel consisted of 17 members and included technical staff from CRITFC, as well as 

toxicologists, epidemiologists, health scientists, and environmental scientists from the 

Indian Health Service (IHS), the Centers for Disease Control and Prevention (CDC), 

Washington and Oregon State health departments, EPA Region 10, and EPA 

Headquarters.

 During a three-day session, the CDC trained interviewers and instructed them in 

procedures and techniques for conducting surveys. The instructors reviewed each 

question on the questionnaire with the interviewers and helped them practice conducting 

interviews. Models of finfish and shellfish were used as visual aids to help identify types 

and amounts of fish consumed.

 A total of 513 tribal members at least 18 years old were directly surveyed. These 

respondents provided information for 204 children age 5 or younger (one child per 

household). The CDC used a systematic probability sampling method to randomly select 

respondents from Indian Health Service client lists of tribal members. Stratified 

systematic sampling was used to collect survey data, with each of the four tribes 

considered an independent stratum.
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 Survey data were transferred from the questionnaires to an electronic database, and all 

data entries were reviewed for missing answers or mistakes. The CDC’s statistical 

database package for analysis of epidemiological data was used to analyze the survey 

data. A private consulting firm conducted a second complete audit of the database, which

involved a question-by-question review of each survey. Appropriate statistical tests were 

used to evaluate the data. The Shapiro-Wilk test was used because the sample size was 

less than 2,000 and indicated that the dataset was not a purely random distribution, but 

rather reflected meaningful trends. In the 1994 CRITFC analysis, outliers whose data 

points seemed unreasonably high due to discontinuity in distribution were ignored on all 

calculations. For highly positively skewed distributions, removing statistical outliers from 

the dataset may bias the upper percentile fish consumption estimates low.

 The study design, implementation strategy, and analyses were submitted to an 

independent peer review panel. The peer review panel consisted of the following 

members: Dr. Patrick West, Ph.D., University of Michigan; Dr. Douglas Robeson, Ph.D., 

Ottawa, Ontario; Dr. Clayton Stunkard, Silver Spring, MD; Dr. H. Joseph Sekerke, Jr., 

State of Florida Department of Health and Rehabilitation Services; Dr. Mary Yoshiko 

Hama, Ph.D., U.S. Department of Agriculture, Food Consumption Research Branch; Dr. 

Kenneth Rudo, Ph.D., State of North Carolina, Department of Environmental Health, 

Division of Epidemiology; Dr. Yasmin Cypel, Ph.D., U.S. Department of Agriculture, 

Food Consumption Research Branch; Dr. Rolf Hartung, Ph.D., Department of 

Environmental and Industrial Health, University of Michigan; and Dr. Dale Hattis, Ph.D.,

Clark University.

 The CRITFC survey design’s credibility is further supported by its use as a template for 

other Pacific Northwest dietary surveys, with refinements specific for the populations 

being surveyed. In addition, the CRITFC survey has been referred to in national guidance 

for policies and procedures for evaluating exposures (EPA’s Exposure Factors Handbook

2009 Update and 2011 Edition).

Additional information reviewed

 Harris and Harper (1997) report that a fish consumption rate of 540 g/day represents a 

reasonable subsistence fish consumption rate for CRITFC’s member tribes who pursue a 

traditional lifestyle. They base this on their review of several nonsubsistence Native 

American studies, two subsistence studies, and personal interviews of members of the 

Umatilla and Yakama Tribes.

 A further examination of Columbia River basin tribal populations used information and 

data collected from the 1994 Columbia River Inter-Tribal Fish Commission’s fish 

consumption survey (Sun Rhodes, 2006). Because of concerns due to chemical 

contaminants in water and fish for tribal fish-consuming populations along the Columbia 

River basin, the tribal populations’ characteristics were examined for children, women of 
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child-bearing age, and tribal elders who may be susceptible to adverse health effects from 

exposure to contaminants due to high fish consumption. A multivariate analysis showed a 

positive association between fish consumption rates and factors including breastfeeding 

after the most recent births, percent of fish obtained non-commercially for women who 

recently gave birth, living off the reservation, and fish consumption for children and the 

elderly. About 50 percent of women, 80 percent of tribal elders, and at least 40 percent of 

children consume nonfillet fish parts. Although this reevaluation did not result in any 

changes or corrections in Columbia River basin tribal consumption rates, it provided 

additional information regarding susceptible tribal populations that consume fish.

4.3.2 Tulalip and Squaxin Island Tribes of the Puget Sound Region

A survey of finfish and shellfish consumption for the Tulalip and Squaxin Island Tribes living in 

the Puget Sound region was conducted in 1994 (Toy et al., 1996). 

The target populations included adult tribal members (18 years or older), randomly selected from 

tribal enrollments who lived on or within a 50-mile radius of the reservation, and children aged 5 

years or younger who lived in the enrolled member’s household. The survey reported 

consumption rates of anadromous, pelagic, bottomfish, and shellfish in grams per kilogram body 

weight per day (g/kg bw/day) over a 1-year period and the portion size of each meal. Adults who 

did not consume fish (less than 1 percent of those contacted) were not included in the survey. 

Finfish/shellfish models were used to estimate portion sizes. Finfish/shellfish preparation methods 

were identified, and sources of finfish and shellfish consumed were reported by tribe and species 

groups.

Species groups included:

 Anadromous fish (Group A). Salmon (Chinook, pink, sockeye, coho, chum); smelt; 

steelhead.

 Pelagic fish (Group B). Cod, dogfish, greenling, herring, perch, pollock, rockfish, 

sablefish, spiny.

 Bottomfish (Group C). Halibut, sole/flounder, sturgeon.

 Shellfish (Group D). Butter clam, clams (manila/littleneck), cockles, Dungeness crab, 

horse clam, moon snail, mussels, oyster, scallops, sea cucumber, sea urchin, shrimp, 

squid.

 Other (Groups E and F). Abalone, barnacles, bullhead, chitons, crayfish, eel, geoduck, 

grunters, limpets, lobster, mackerel, manta ray, octopus, razor clam, shark, skate, trout.
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A total of 190 successful interviews were completed from February 25 through mid-May for 

adult tribal respondents. A tribal parent or guardian answered questions about the fish 

consumption for children from the same household. Only one child per household, selected 

randomly, was included in the survey, for a total of 69 children. Results from half of the adult 

respondents in the Tulalip Tribes were dropped because one of the tribal interviewers did not 

follow the survey interview protocol. However, repeat interviews were conducted by telephone 

as a follow-up with 10 percent of the survey respondents. The timing of the survey period may 

bias the fish consumption estimates. Salmon are present in Puget Sound during different times of 

the year. The survey was administered during a low season for anadromous (salmon) fish harvest 

but prior to and during the shellfish harvest season. Because of the timing of the survey, 

respondents may have underestimated their salmon consumption and overestimated shellfish 

consumption.

Anadromous finfish and shellfish were most frequently consumed. The main source for the most 

frequently consumed fish (anadromous finfish and shellfish) was local water bodies of Puget 

Sound. Fish fillets with skin were consumed by up to 40 percent of the tribal respondents, with 

mean percent consumption of fish parts (head, bones, eggs, organs, and skin) for up to 11 percent 

of tribal respondents consuming anadromous fish. Although the survey identified fish parts 

consumed by respondents, it did not include complex tribal seafood recipes. 

Weight adjusted consumption rates were calculated and reported by tribe, age, gender, income, 

and species group. The adult mean and median consumption rates for all forms of fish combined 

were 0.89 and 0.55 g/kg bw/day for the Tulalip Tribes and 0.89 and 0.52 g/kg bw/day for the 

Squaxin Island Tribe, respectively. Age-adjusted median fish consumption rates for the Tulalip 

Tribes were 53 g/day for males and 34 g/day for females. Age adjusted median fish consumption 

rates for the Squaxin Island Tribe were 66 g/day for males and 25 g/day for females. The mean 

and median consumption rate for children, 5 years and younger for both tribes combined, were 

0.53 and 0.17 g/kg bw/day, respectively. 

Ecology’s statistical analysis of the Tulalip survey data (individual level respondent data) 

provides estimates of anadromous, non-anadromous, shellfish, all finfish/shellfish consumption 

estimates, and source of harvest (Table 23, Figures 5 and 6). 
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Table 23. Tulalip Tribal Adult Fish Consumption Rates by Species Group and 

Source

Population

Tribal Species Group

Harvest 

Source of 

Fish

Descriptive Statistics (g/day)

50th

Percentile Mean 75thPercentile

90th

Percentile

95th

Percentile

Tulalip

All Fish All Sources 44.5 82.2 94.2 193 268

Finfish All Sources 22.3 44.1 49.1 110 204

Shellfish All Sources 15.4 42.6 40.1 113 141

Non-anadromous All Sources 20.1 45.9 52.4 118 151

Anadromous All Sources 16.8 38.1 43.3 92.1 191

All Puget 

Sound 29.9 59.5 75.0 139 237

Finfish Puget 

Sound 13.0 31.9 33.1 78.4 146

Shellfish Puget 

Sound 14.2 36.9 40.1 111 148

Non-anadromous Puget 

Sound 14.8 35.5 38.8 109 145

Anadromous Puget 

Sound 11.8 30.4 32.4 66.0 148

See Polissar et al., 2012, Table E-1.

Figure 5. Tulalip Tribal Adult Fish Consumption Rates, Harvested from

All Sources

43.3

52.4

40.1

49.1

94.2

191

151

141

204

268

0 50 100 150 200 250 300

Anadromous

Non-Anadromous

Shellfish

Finfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 23)
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Figure 6. Tulalip Tribal Adult Fish Consumption Rates, Harvested from

Puget Sound

Ecology’s statistical analysis of the Squaxin Island survey data provides consumption estimates 

for anadromous, non-anadromous, shellfish, and all finfish/shellfish, and data on source of 

harvest (Table 24, Figures 7 and 8). Consumption rate estimates for the Squaxin Island adult fish 

consumers are based on published results of the fish dietary survey.

Table 24. Squaxin Island Tribal Adult Fish Consumption Rates by Species Group 

and Source

Population

Tribal Species Group

Harvest 

Source of 

Fish

Descriptive Statistics (g/day)

50th

Percentile Mean 75thPercentile

90th

Percentile

95th

Percentile

Squaxin

Island

All fish All 44.5 83.7 94.4 206 280

Finfish All 31.4 65.5 82.3 150 208

Shellfish All 10.3 23.1 23.9 54.0 83.6

Non-anadromous All 15.2 28.7 32.3 70.5 95.9

Anadromous All 25.3 55.1 65.8 128 171

All fish Puget Sound 30.0 56.4 63.5 139 189

Finfish Puget Sound 21.6 45.0 56.5 103 143

Shellfish Puget Sound 6.4 14.3 14.8 33.5 51.9

Non-anadromous Puget Sound 6.5 12.3 13.9 30.3 41.2

Anadromous Puget Sound 20.2 44.1 52.6 103 137

See Polissar et al., 2012, Table E-1.

32.4

33.1

38.8

40.1

75.0

148

145

148

146

237

0 50 100 150 200 250 300

Anadromous

Non-Anadromous

Shellfish

Finfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 23)
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Figure 7. Squaxin Island Tribal Adult Fish Consumption Rates, Harvested

from All Sources

Figure 8. Squaxin Island Tribal Adult Fish Consumption Rates, Harvested

from Puget Sound

65.8

32.3

23.9

82.3

94.4

171

95.9

83.6

208

280

0 50 100 150 200 250 300

Anadromous

Non-Anadromous

Shellfish 

Finfish

AllFish

grams/day

95th %ile

90th %ile

75th %ile

Mean

52.6

13.9

14.8

56.5

63.5

137

41.2

51.9

143

189

0 50 100 150 200 250 300

Anadromous

Non-Anadromous

Shellfish 

Finfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 24)

(See Table 24)
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Technical defensibility

As summarized in Table 25 below, Ecology has determined that the survey of Tulalip and 

Squaxin Island Tribes of the Puget Sound Region is relevant to Washington and satisfies 

measures of technically defensibility (Toy et al., 1996).

Table 25. Fish Consumption Survey of the Tulalip and Squaxin Island Tribes of 

the Puget Sound Region

Metric Observations and Comments Evaluation

1. Survey method development

a. Type and description of 

survey vehicle

Personal interview survey; 24-hour and seasonal dietary recall; 

finfish/shellfish identification, portion, frequency, preparation, and 

harvest locations.

The survey method 

and vehicle were 

developed in a 

technically defensible 

manner.

b. Collaboration and review 

Survey was developed in collaboration with Washington DOH, 

Ecology, EPA Region 10, Tulalip Tribal Department of 

Environment, Suquamish Tribal Fisheries Department, Board of 

Directors for Tulalip and Squaxin Island Tribes, Columbia River 

Inter-Tribal Fish Commission, and Fred Hutchinson Cancer 

Research Center in Seattle.

c. Beta testing Pilot survey and repeat interviews conducted

2. Survey execution

a. Establish and document 

execution standards

Execution of survey questionnaire documented with identifiable 

QA/QC procedures.

The survey vehicle 

was appropriately 

executed and 

documented; use of 

fish models was 

documented.

b. Document staff training Two members from each tribe trained to conduct interviews.

c. Finfish/shellfish models used Finfish and shellfish models used for multiple species.

3. Publication of results

a. Where were results 

published? Are they clear 

and complete?

Finfish/shellfish identification, portion, frequency, preparation, and 

harvest locations documented and reported.

The data presented in 

the joint Tulalip and 

Squaxin Island tribal 

publication are

sufficient to develop 

consumption 

distributions with 

percentiles.

b. Methodology reported All phases of method development documented and reported.

c. Results tabulated and stated Tabulated species-specific consumption with descriptive statistics.

d. Conclusions clearly reported Conclusions reported with follow-up interviews for reliability and 

representation

f. Variability and uncertainty Noted and documented with note of “outliers” with reported rates 

for Tulalip and Squaxin Island Tribes.

g. How is the potential for bias 

addressed?

The possibility for bias in the survey methodology is recognized 

and discussed. Survey results from one interview did not follow 

protocol and were eliminated.

4. Applicability and utility for regulatory decision making

a. Representation of target 

population 

Included range of different rates for enrolled Tulalip and Squaxin 

Island tribal members This survey meets the 

standards of 

relevance, 

applicability, and utility 

and is appropriate for 

use in regulatory 

decision making.

b. Currency of information

Survey conducted in 1996; more recently the consumption 

estimates were used by Oregon DEQ in developing water quality 

standards (2011). EPA Region 10 has also utilized the Suquamish 

survey in its internal policy on assessing tribal seafood 

consumption risks.

c. Sufficiency of data

The data are sufficient to provide distribution and percentile 

estimates of fish consumption for Tulalip and Squaxin Island tribal 

populations.
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Metric Observations and Comments Evaluation

5. Overall technical suitability for regulatory decision making 

a. Range of technical 

defensibility Technically defensible dietary survey of the Squaxin Island Tribe.

Ecology concludes the 

survey is technically 

defensible. b. Appropriateness for use in 

risk-based standards

Data were reanalyzed by Nayak L. Polissar, Ph.D., to provide 

consumer-only consumption rates. It is sufficient to provide 

distribution and percentile estimates of fish consumption as 

required for risk-based decision making. 

Source: Toy et al., 1996.

The technical rigor applied to the design and conduct of the Tulalip and Squaxin Island tribal fish 

dietary survey illustrates a high level of collaboration across state and federal agencies and tribal 

governments, and closely parallels the CRITFC fish dietary survey. The salient features of this 

survey are noted below:

 A Technical Advisory Panel was formed to provide assistance and oversight for planning, 

developing methods, and conducting the dietary survey. Panelists included numerous 

professionals from the Washington State Departments of Health and Ecology, U.S. 

Environmental Protection Agency, and the U.S. Public Health Service.

 Tulalip and Squaxin Island tribal staff assisted with organizing and executing the survey. 

They also provided tribal consultations with other tribal governments and organizations 

including the Columbia River Inter-Tribal Fish Commission, Portland, Oregon.

 A toxicologist, epidemiologist, tribal biologists, and statistical consultants provided 

professional guidance and consultations.

4.3.3 Suquamish Tribe 

The Suquamish Tribal Council conducted a fish consumption survey during July, August, and 

September 1998 of Suquamish tribal members living on and near the Port Madison Indian 

reservation in the Puget Sound area (The Suquamish Tribe, 2000). The survey was conducted to 

determine the finfish/shellfish consumption rates, habits, and patterns of the Suquamish Tribe. 

Also, the study was conducted to identify fish consumption-related cultural practices and tribal 

characteristics that might affect fish consumption rates, patterns, and habits. The survey was 

administered during months of high availability of fisheries, which may have had a positive bias 

on the reported fish consumption estimates.

Consumption data were based on a random sample of adults (16 years and older) selected from 

the tribal enrollment roster. Of 425 tribal members of all ages living on or near the reservation, 

284 adults were identified as eligible to participate in the survey. Of these, 142 adults were 

randomly selected and 92 participated in the survey, for a 64.8 percent participation rate. 

Consumption data were collected for 31 children under the age of 6 who were living in the same 

household with adult respondents at the time of the survey. Some households had more than one 

child who was surveyed. The survey questionnaire was administered by trained tribal members 
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using personal interviews and included two parts: a 24-hour dietary recall, and an assessment of 

fish consumption over the course of a year.37 In addition, the survey included information on:

 Fish species identification, portion sizes, frequency of consumption, methods of 

preparation, harvest locations.

 Shellfish consumption, methods of preparation, harvest location.

 Changes in consumption over time, cultural information, physical information, and 

socioeconomic information.

Finfish/shellfish models were used to assist tribal respondents regarding amounts and types 

consumed. Booklets were used to assist in identifying harvest locations of seafood consumed. 

Finfish/shellfish were grouped into categories based on similarities in life history and practices 

of tribal members who fish for subsistence, ceremonial, and commercial purposes. The majority 

of finfish/shellfish consumed by the Suquamish Tribe was harvested from Puget Sound, with 

Pacific salmon and shellfish consumed more than other fish.

All 92 adult tribal respondents reported consuming some type of fish; hence, no non-consumers 

of fish were surveyed. Survey results were recorded as grams per kilogram per day (g/kg/day) 

along with the respondent’s body weight. Adult respondents reported a mean consumption rate 

of all finfish and shellfish consumption rate of 2.71 g/kg/day. For children under 6 years old, the 

mean consumption of all finfish and shellfish was 1.48 g/kg/day. Below are weight-adjusted

survey results for Suquamish adult fish consumers.

Ecology’s statistical analysis of the Suquamish dietary data for Suquamish tribal adult fish 

consumers provides finfish, shellfish, and non-anadromous consumption rates by species groups 

and sources of fish consumed (Table 26, Figures 9 and 10). 

 

37 Estimates of maximum amounts of fish consumed, either as a rate or portion size, from a highly positively skewed dataset can be very large 

with estimates of several pounds of fish consumed. These maximum fish consumption estimates reflect the maximum amount of fish consumed 

by a subset of fish consumers within a larger indigenous fish-consuming population. Harper, Harris, and Donatuto have indicated that these 

very high fish consumers are true subsistence populations (fish consumption rate exceeding 454 g/day or 1 pound/day) within the larger 

indigenous fish-consuming populations (Harris and Harper, 1997; Harper and Harris, 2008; Donatuto and Harper, 2008).
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Table 26. Suquamish Tribal Adult Fish Consumption Rates by Species Group 

and Source

Population

Tribal

Species 

Group

Harvest 

Source of

Fish

Descriptive Statistics (g/day)

50th

Percentile Mean 75thPercentile

90th

Percentile

95th

Percentile

Suquamish 

Tribe

All All Sources 132 214 284 489 797

Shellfish All Sources 64.7 134 145 363 615

Nonanadromous* All Sources 102 169 219 377 615

Anadromous All Sources 27.6 48.8 79.1 133 172

All Puget Sound 57.5 165 221 397 767

Shellfish Puget Sound 52.4 109 118 294 499

Nonanadromous* Puget Sound 49.1 126 116 380 674

Anadromous Puget Sound 21.8 38.6 62.5 105 136

See Polissar et al., 2012

*Based on an assumed n = 90 consumers.

Figure 9. Suquamish Tribal Adult Fish Consumption Rates, Harvested from All 

Sources

79.1

219

145

284

172

615

615

797

0 100 200 300 400 500 600 700 800 900 1000

Anadromous

Non-Anadromous

Shellfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 26)
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Figure 10. Suquamish Tribal Adult Fish Consumption Rates, Harvested from 

Puget Sound

Technical defensibility

As summarized in Table 27 below, Ecology has determined that the 2000 survey of the 

Suquamish Indian Tribe of the Port Madison Indian Reservations of Puget Sound is relevant to 

Washington and satisfies measures of technical defensibility.

Table 27. Fish Consumption Survey of the Suquamish Indian Tribe of the Port 

Madison Indian Reservation, Puget Sound Region

Metric Observations and Comments Evaluation

1. Survey method development

a. Type and description of 

survey vehicle

Personal interview survey; 24-hour and seasonal dietary recall;

finfish/shellfish identification, portion, frequency, preparation, and harvest 

locations.

The survey method 

and vehicle were 

developed in a 

technically defensible 

manner.

b. Collaboration and review 

Survey was developed in collaboration with Washington DOH, Ecology, 

Agency for Toxic Substances and Disease Registry, University of 

Washington, EPA Region 10, and Suquamish Tribal Fisheries 

Department.

c. Beta testing Beta testing documented.

2. Survey execution

a. Establish and document 

execution standards

Execution of survey questionnaire documented with identifiable QA/QC 

procedures.

The survey vehicle 

was appropriately 

executed and 

documented; use of 

fish models was 

documented. 

b. Document staff training Training of personnel was conducted by trained Suquamish Tribe

members.

c. Finfish/shellfish models 

used

Seafood models and a display booklet of seafood illustrations for multiple 

species were used to aid in identifying the amount of seafood consumed.

62.5

116

118

221

136

674

499

767

0 100 200 300 400 500 600 700 800 900 1000

Anadromous

Non-Anadromous

Shellfish

All Fish

grams/day

95th %ile

90th %ile

75th %ile

Mean
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Metric Observations and Comments Evaluation

3. Publication of results

a. Where were results 

published? Are they clear 

and complete?

Finfish/shellfish identification, portion, frequency, preparation, and 

harvest locations were documented and reported.

Suquamish Tribe

publication with welldefined method, 

analysis of species 

consumed, clear 

data analysis and 

interpretation.

b. Methodology reported The methodology used is clearly described and documented.

c. Results tabulated and

stated

Survey results are reported and summarized in a tabular format suitable 

for distributional descriptive statistics.

d. Conclusions clearly 

reported

Conclusion reported with follow-up interviews for reliability and 

representation.

e. Variability and uncertainty Noted and documented with “outliers” identified and determined impact of 

outliers on consumption rate statistics of interest.

f. How is the potential for 

bias addressed?

The possibility for bias in the survey methodology is recognized and 

discussed.

4. Applicability and utility for regulatory decision making

a. Representation of target 

population Included range of different rates for enrolled Suquamish Tribe members.

This survey meets 

the standards of 

relevance, 

applicability, and 

utility and is 

appropriate for use in 

regulatory decision 

making.

b. Currency of information

The survey was conducted in 1999; more recently, the consumption 

estimates were used by Oregon DEQ for developing water quality 

standards (2011).

c. Sufficiency of data

The fish-consumption estimates are sufficient to provide descriptive 

statistics for defined distributions and percentiles for Suquamish Tribal

population. EPA Region 10 has also utilized the Suquamish survey 

information in its internal policy on assessing tribal seafood consumption 

risks.

5. Overall technical suitability for regulatory decision making

a. Range of technical 

defensibility Technically defensible dietary survey of the Suquamish Tribe.

The survey is

technically defensible

with rates and 

portion sizes 

reinforced by 

independent 

technical 

documentation 

(Harper and Harris, 

1997, 2008; 

Donatuto and 

Harper, 2008).

b. Appropriateness for use in

risk-based standards

The data are sufficient to provide distribution and percentile estimates of 

fish consumption as required for risk-based decision making. Seafood 

consumption data provided are for consumption of seafood from all 

sources. EPA Region 10’s tribal seafood consumption framework 

provides an approach for developing consumption rates of regionally 

harvested seafood.

Source: The Suquamish Tribe, 2000.

Many features of the Suquamish tribal member dietary survey are similar to and reflect the 

experience gained during the development and conduct of the CRITFC dietary survey. These 

features were identified and described in the survey report, which confers and supports the 

technical defensibility of the study design, dietary methodology, execution of the survey, and 

results and conclusions drawn from the dietary survey (The Suquamish Tribe, 2000). The salient 

features of the technical review procedures for the Suquamish dietary review are noted below:
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 The survey was funded through the Agency for Toxic Substances and Disease Registry 

(ATSDR), U.S. Department of Health and Human Services, and Washington State 

Department of Health with collaboration regarding the survey questionnaire design to 

elicit useful dietary information from tribal respondents.

 Technical review and oversight of the planning, design, execution, and evaluation of the 

data included biologists, epidemiologists, toxicologists, and statisticians from multiple 

agencies.

 The Suquamish Tribal staff included interviewers, biologists, and a principle investigator. 

 Technical collaboration, consultations, and reviews were conducted by the Washington 

Departments of Ecology and Health, University of Washington, U.S. Department of 

Health and Human Services, Fred Hutchinson Cancer Research Institute, and the U.S. 

Environmental Protection Agency.

 Data analysis and review were conducted by two Seattle statistical consulting firms, 

Mountain-Whisper-Light Statistics and StatPro Consultants.

4.4 Asian and Pacific Islanders 

An Asian and Pacific Islander (API) seafood consumption study was conducted during the spring 

and summer of 1997 in King County, Washington, to obtain information on consumption rates, 

species and seafood parts consumed, and preparation methods for first- or second-generation 

members of the API community (Sechena et al., 1999). Survey participants were API seafood 

consumers 18 years or older. The study was conducted in three phases:

 Phase I: Identify target API ethnic groups and develop appropriate questionnaires in the 

language required to administer the questionnaire to each API ethnic group.

 Phase II: Characterize seafood consumption for 10 API ethnic groups within the King 

County study area.

38

 Phase III: Develop culturally appropriate health messages on risks related to seafood 

consumption and disseminate to API community.

Of the 202 respondents, 89 percent were first API generation (born outside the United States). 

API participants were interviewed by trained representatives from each of the 10 API ethnic 

communities represented and asked to report on the number of annual servings and portion size 

of the servings. Participants reported their own body weights. Fish consumption rate results were 

reported as grams per kilogram per day. Because the survey was based on dietary recall, the 

authors selected 20 API respondents to interview a second time, to assess the reliability of the 

 

38 The 10 API ethnic groups are Cambodian, Chinese, Filipino, Hmong, Japanese, Korean, Laotian, Mien, Samoan, and Vietnamese.
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responses. The results suggest that the estimated consumption rates are reliable for the API 

community study area.

Table 28 provides the weight-adjusted survey results for API adult fish consumers.

Table 28. Adult Respondents to the Asian and Pacific Islander Survey

Number of 

Adults 

Surveyed

Descriptive Statistics (g/day)

Mean Median Percentiles

75th 90th 95th 99th

Asian and Pacific Islanders 202 117 78 139 236 306 -

Source: Adapted from Oregon DEQ, 2008, Table 3. See also Polissar et al., 2012; Sechena et al.,1999, 2003.

Survey results indicate that shellfish were consumed more by the API community than any other 

group of fish. More than 75 percent of the respondents consumed shrimp, crab, and squid. 

Salmon and tuna were the most frequently consumed finfish. For all fish groups, 79 to 97 percent

of the seafood consumed came from either groceries/street vendors or restaurants. Japanese 

consume a greater percentage of finfish than shellfish (52 percent), while Vietnamese consume 

more shellfish (50 percent). The mean and median consumption rates for all seafood combined 

for the 10 API ethnic groups were 1.9 g/kg bw/day and 1.4 g/kg bw/day, respectively. The 

average shellfish consumption rate for the API community was 0.87 g/kg bw/day. The API 

community consumed more shellfish than all of the combined categories of finfish consumed 

(average finfish consumption is 0.82 g/kg bw/day).

Technical defensibility

As summarized in Table 29 below, Ecology has determined that the 1999 survey of King County 

Asian and Pacific Islanders is relevant to Washington and satisfies measures of technical 

defensibility. The King County, Washington, API fish consumption survey is considered an 

outstanding model (gold standard) for culturally sensitive fish dietary surveys.

The fish dietary survey was administered in two phases: 

 Phase 1: Identification of appropriate API ethnic groups to survey, design culturally 

sensitive fish dietary survey questionnaire, and then translate and pilot test the 

questionnaire for each API ethnic group.

 Phase 2: Established partnership between the Refugee Federation Service Center and the 

University of Washington’s Environmental Health Department to help support the 

University of Washington Human Subjects Committee for the design, survey instruments, 

and execution of the survey.
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Table 29. Asian and Pacific Islander Seafood Consumption Study

Metric Observations and Comments Evaluation

1. Survey method development

a. Type and description of 

survey vehicle

Personal interview survey; 24-hour dietary recall; conducted in three

phases.

The survey method and 

vehicle were developed 

in a technically 

defensible manner.

b. Collaboration and review 

Survey was developed in collaboration with a Community Steering 

Committee (representatives of the API community, Washington DOH, 

Ecology, EPA Region 10, University of Washington, and Seattle 

Refugee Federation Service Center).

c. Beta testing The testing of the survey was conducted in phases with follow-up 

interviews to assess reliability of responses.

2. Survey execution

a. Establish & document 

execution standards

Seafood consumption studies for 10 API groups in King County, 

Washington. Technical execution guided by Community Steering, 

Technical, and Advisory Committees.

The survey was 

appropriately executed 

and documented; use 

of fish models was 

documented.

b. Document staff training Trained bilingual interviewers from API community.

c. Finfish/shellfish models used Seafood models were used to represent approximate portion sizes.

3. Publication of results

a. Where were results 

published? Are they clear 

and complete?

Information on types of seafood consumed, source of seafood, 

preparation methods, frequency and portion size consumed, 

demographic information clearly reported.

Robust analysis and

evaluation of API 

community fish 

consumption habits and 

patterns

b. Methodology reported Phase II (fish consumption) followed from identification target API 

populations with ethnic and language-specific questionnaires.

c. Results tabulated and stated Tabulated species-specific consumption across 10 different API 

ethnic populations; included food preparation methods.

d. Conclusions clearly reported Conclusions clearly reported with follow-up interviews.

e. Variability and uncertainty Variability and uncertainty were qualitatively recognized and noted.

f. How is the potential for bias 

addressed?

The possibility for bias in the survey methodology is recognized and 

discussed.

4. Applicability and utility for regulatory decision making

a. Representation of target 

population 

The survey included a range of different API ethnic groups to 

evaluate consumption representative of API population. This survey meets the 

standards of relevance, 

applicability, and utility 

and is appropriate for 

use in regulatory 

decision making.

b. Currency of information

The survey was conducted in 1999; more recently, the consumption 

estimates were used by Oregon DEQ in developing water quality 

standards (2011).

c. Sufficiency of data

The consumption estimates are sufficient to provide descriptive 

statistics for defined distributions and percentiles for different API 

populations.

5. Overall technical suitability for regulatory decision making

a. Range of technical 

defensibility

Technically defensible dietary survey of API populations in King 

County, Washington.

Ecology concludes the 

survey is technically 

defensible. b. Appropriateness for use in 

risk-based standards

The data are sufficient to provide distribution and percentile estimates 

of fish consumption as required for risk-based decision making. The 

API survey did not correct for cooking weight loss or regionally 

harvested seafood. See write-up on EPA Region 10’s reanalysis of 

the API survey (Kissinger, 2005).

Source: Sechena et al., 1999.
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Sechena et al., 2003 provides a detailed description of the API fish dietary survey. Detailed 

descriptions of the survey methodology include:

 A methodology overview.

 Survey instruments.

 Sampling strategy including respondent selection criteria, API ethnic representation and 

recruitment, questionnaire administration, data analyses.

 Statistical methods used to derive fish consumption rates, treatment of outliers, 

hypothesis testing, and statistical significance and descriptive statistics.

 Results and discussion with tabulated results in g/kg/day for upper percentile estimates.

4.4.1 Reanalysis by EPA Region 10

EPA Region 10 reanalyzed the API data to correct for cooking weight loss, regional seafood 

harvest, and extrapolation from the survey to King County API populations (Kissinger, 2005). 

This reanalysis was used to establish cleanup levels in the Lower Duwamish Waterway

(Windward Environmental, 2007). The EPA Region 10 reanalysis of the API 1999 survey 

included only data for individuals consuming seafood from King County. Weighting factors for 

King County consumers for various ethnic groups were a function of the percentage of that 

ethnic group as determined in the census and the number of individuals in that ethnic group that 

consumed seafood from King County. The 95th percentile ingestion rate (defined as the 

reasonable maximum exposure [RME] scenario) was developed from the consumer-only dataset 

of weighted ingestion rates. Adjustments were made to account for some of the shellfish 

consumption reported on a cooked-weight basis rather than on a wet-weight basis. Revised 

estimates of average raw shellfish consumption were made by using 25 and 50 percent cooking 

loss correction factors for those shellfish species for which consumption was reported on a 

cooked-weight basis. EPA calculated demographically weighted mean ingestion rates for each 

seafood category for individuals who consumed some seafood caught in King County. 

Demographically weighted mean ingestion rates were used to derive the percentage of 

consumption of each seafood category. These percentages were then applied to the total 

consumption rate (95th percentile of total King County API seafood consumption of 57.1 g/day) 

to derive consumption rates for each seafood category. 

Anadromous fish were not included in the fish consumption scenario because it is problematic to 

apportion salmon (anadromous fish) contaminant body burden to site-specific chemical 

contaminants. To estimate the API central tendency consumption rate, the 50th percentile of total 

King County API consumption was multiplied by the percentage of consumption for the various 

seafood categories. Total non-anadromous seafood consumption for the API exposure scenarios 

was 51.1 g/day and 5.3 g/day for the RME and central tendency estimates, respectively.
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Reanalysis of the consumption of shellfish (mussels, crabs, and clams) for the API exposures 

used average demographically weighted consumption of these shellfish species harvested only 

from King County. These shellfish consumption estimates were used to calculate the percentage 

of each shellfish type consumed. The demographic weighting factor was used to estimate the 

consumption of clams, mussels, and crabs. The crab consumption rates were apportioned among 

crab whole body and edible meat, and the benthic (demersal) fish consumption rates were 

apportioned among benthic fish fillet and whole body. EPA Region 10 provided 

demographically weighted average percentages of crab whole-body and crab edible-meat 

consumption by API populations consuming at least some King County seafood. Also, EPA 

Region 10 provided average demographically weighted percentages of whole-body and fillet 

consumption by API members consuming at least some King County seafood.

Technical defensibility

Ecology has determined that the EPA Region 10 reanalysis of the 1999 API survey is a relevant 

and technically defensible approach for a site-specific evaluation (Lower Duwamish Waterway).

Reanalysis of the API data by EPA Region 10 for King County API adult consumers provided

central and upper bound estimates of fish consumption (Table 30). The reported consumption 

estimates include no adjustment for cooking and may be slightly biased low (i.e., 

underestimated).

The Kissinger (2005) demographic weighting methodology is not recommended for projecting

fish dietary patterns for API populations beyond King County. Because of the small number of 

respondents for each API ethnic group, there would be a high level of uncertainty in projecting

statewide API fish dietary patterns from King County API fish dietary information.

It should be noted that Asian and Pacific Islanders include a broad range of ethnicities39 and that 

the Kissinger (2005) analysis presents fish consumption estimates determined from aggregating 

fish consumption data for small numbers of individuals from these varied ethnic groups. Future 

fish consumption survey efforts should consider more comprehensive analysis of quantitative 

fish consumption and cultural factors associated with fish consumption by individual ethnic 

groups.

 

39 For the ethnicities listed here, the first number is the number of respondents from that ethnic group; the second number is the percentage of 

the total number of respondents represented by that group (Sechena et al., 2003, Table 1). 

Cambodian 20/≈10% Mien 10/≈5%

Chinese 30/≈14% Hmong 5/≈2%

Filipino 30/≈14% Samoan 10/≈5%

Japanese 29/≈14% Vietnamese 26/≈13%

Korean 22/≈10% All API Ethnicity 202

Laotian 20/≈10%
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Table 30. API Adult Seafood Consumption Rates by Species Group and Source

Population

API Species Group Source of Fish

Descriptive Statistics (g/day)

50th

Percentile

90th

Percentile

95th

Percentile

Asian-Pacific 

Islander (API)

Total seafood 

consumption All sources 74.0 227 286

All species Harvested anywhere 6.5 25.9 58.8

All species Harvested from King 

County 5.7 22.2 48.4

Non-anadromous 

species Harvested anywhere 6.2 37.9 54.1

Non-anadromous 

species

Harvested from King 

County 6.0 20.1 45.5

Sources: Adapted from Kissinger, 2005, Table 5. See also Polissar et al., 2012. 

In recommending fish consumption estimates for API populations, EPA Region 10 proposed 

using estimates that accounted for weight lost during cooking. The EPA Region 10 rates 

included adjustments to account for cooking loss (Table 31).

Table 31. API Seafood Consumption Rates Adjusted for Cooking Loss

Population

API Species Group Source of Fish

Descriptive Statistics (g/day)

50th

Percentile

90th

Percentile

95th

Percentile

Asian-Pacific 

Islander (API)

Total seafood 

consumption All sources 77.8 236 306

All species Harvested anywhere 6.9 49.1 76.3

All species Harvested from King 

County 5.8 25.5 57.1

Non-anadromous 

species Harvested anywhere 7.1 54.2 72.3

Non-anadromous 

species

Harvested from King 

County 6.6 33.4 57.3

Source: Adapted from Kissinger, 2005, Table 8. See also Polissar et al., 2012.
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Source: Adapted from Kissinger, 2005, Table 8. See also Polissar et al., 2012.

Figure 11. API Adult Fish Consumption Rates, Harvested from King County (KC) 

and Other Sources, Adjusted for Cooking Loss

4.5 Recreational fishers

Recreational fishing is a popular activity and consideration of recreational fishers provides 

additional information about fish consumption from Washington waters. Although data for the 

general population is useful for evaluating fish consumption rates, data on recreational fishing 

are needed to assess exposure to individuals with potentially higher fish consumption levels. 

Recreational fishers may consume fish more frequently, and may consume larger portions at 

each meal, than the general population. In addition, they may frequently fish from a single 

contaminated source. These factors may put recreational fishers at higher risk of exposure to 

contaminants in finfish and shellfish. 

Several studies have been conducted in Washington State to evaluate the fish consumption of 

recreational anglers. The Technical Issue Paper Recreational Fish Consumption Rates provides 

detailed information on these surveys and their findings. Many of the available recreational 

angler surveys were done in the 1980s and are not as current as the other surveys noted above. 

Additionally, recreational surveys are generally creel, rather than personal interview surveys. 

These fish consumption surveys can be used to provide an estimate of mean and upper (90th to 

95th) percentile marine/estuarine and freshwater fish consumption rates for recreational fishers in 

Washington State, as follows:

57.3

72.3

57.1

76.3

306

0 50 100 150 200 250 300 350

Non-Anadromous (harvested in KC)

Non-Anadromous (total harvested)

All fish (harvested in KC)

All fish (total harvested)

Total (all sources)

grams/day

95th%ile

90th %ile

50th %ile

(See Table 31)
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 Mean consumption rates for both freshwater and marine/estuarine finfish and shellfish 

are in the range of 20 to 60 g/day.

 Upper percentile consumption rates are in the range of 200 to 250 g/day for marine/

estuarine finfish and shellfish, and in the range of 100 to 150 g/day for freshwater fish.

Ecology believes that recreational angler surveys employing a creel methodology are far less 

appropriate for regulatory use than surveys that utilize a personal interview approach (see Tables 

9 and 10).

4.6 Additional fish consumption rate information 

evaluated by Ecology 

In addition to the studies summarized in Section 4.1 to 4.5 above, Ecology considered a range of 

other sources of information about fish consumption in Washington, as listed in Table 32. These 

sources provide information on resource use and historical information about fish consumption, 

which provides a larger and more complete view of finfish and shellfish harvest and 

consumption in Washington. Appendix B provides a summary of additional tribal fish 

consumption evaluations reviewed during preparation of this Technical Support Document.
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Table 32. Fish Consumption Information Relevant to Washington and Considered by Ecology

Tribal Surveys Description

A Fish Consumption Survey of the Umatilla, Nez 

Perce, Yakama, and Warm Springs Tribes of the 

Columbia River Basin a

Fish consumption habits & patterns of selected Native American tribes that reside and harvest fish in the Columbia River Basin. Includes Yakama 

and Umatilla tribes from Washington; Nez Perce and Warm Springs tribes from Oregon State.

A Fish Consumption Survey of the Tulalip and Squaxin 

Island Tribes of the Puget Sound Region b Puget Sound regional survey for two tribes. Provides information on both finfish and shellfish consumption.

Fish Consumption Survey of the Suquamish Indian 

Tribe of the Port Madison Indian Reservations, Puget 

Sound Region c

Puget Sound regional survey for two tribes. Provides information on both finfish and shellfish consumption.

Survey of Asian and Pacific Islander

Asian and Pacific Islander Seafood Consumption 

Study d

King County specific fish consumption estimates for Asian and Pacific Islanders. Survey information has been used by EPA Region 10 to estimate 

rates for Asian and Pacific Islanders for other Puget Sound areas. Using Sechena et al., 1999, EPA Region 10 reanalyzed data to support 

Ecology in developing site-specific MTCA cleanup standards and risk assessment for the Lower Duwamish Waterway and Elliott Bay.e

U.S. General Population

Estimated Per Capita Fish Consumption in the United 

States f

Includes fish consumers and non-consumers. (These data were used by Oregon DEQ to estimate the percentage of fish consumers and nonconsumers in Oregon.)

State Assessments, Evaluations, and Advisories

Washington State Department of Health Fish 

Advisories

Various water body-specific fish consumption rates. DOH advisories provide information on fish meals that should be avoided or can be safely eaten 

for analytically determined contaminant levels in fish tissue.

Lower Duwamish Waterway Baseline Human Health 

Risk Assessment g

Provides fish consumption information derived from Puget Sound surveys as incorporated in the EPA Region 10 framework describing tribal 

seafood consumption risk assessment for Resource Conservation and Recovery Act (RCRA) and Comprehensive Environmental Response, 

Compensation, and Liability Act (CERCLA) cleanup sites in Puget Sound and modified by tribal consultation. Develops sediment cleanup standards 

based on tribal RME scenarios.

Lower Elwha Klallam Tribe/Port Angeles h, i In collaboration with Ecology and using the EPA Region 10 framework developed tribal fish consumption rate. Cleanup standards are based on a 

tribal RME.

Lake Roosevelt, DOH j DOH in cooperation with the Spokane Tribe, water body- and angler-specific creel survey; 42 fish meals/year; assuming 8-ounce meal. This is 

approximately 26 g/day.

Sinclair Inlet Bremerton Naval Complex k Risk-based screening levels based on Suquamish Tribe adult and children finfish/shellfish ingestion rates and recreational sport fishers (see 

Appendix A).

Lake Whatcom, DOH l

Provided estimated species-specific fish meals sizes for commonly caught and consumed Lake Whatcom fish species (crayfish, cutthroat trout, 

kokanee, yellow perch, smallmouth bass) with median rates in g/meal; from low (crayfish) of 24 g/meal and high (smallmouth bass) of 220 g/meal.

Rhone-Poulenc m Cleanup standards based on Tulalip tribal and Asian and Pacific Islander seafood consumption data. Range of fish consumption rates referred to 

and documented in Lower Duwamish Waterway Human Health Risk Assessment.

South Aberdeen-Cosmopolis Area n Chinook, coho, chum; anadromous steelhead and cutthroat trout commonly found and available for harvest. Evaluates fish habitat and recommends 

habitat restoration and enhancement.

Naval Base Kitsap – Keyport, Washington o Based on Suquamish Tribe shellfish (clams, mussels, crabs, oysters) consumption rate. Based on U.S. general population rate 54 g/day to 

Suquamish rate 632 g/day for clams.

Oakland Bay, Shelton p Water body-specific evaluation. A range of shellfish consumption rates used, 17.5, 60, 175, 260 g/day; based in part on Squaxin Island tribal 

consultations. 

Umatilla Tribal Water Quality Standard q Consumption rate of 389 g/day approved by EPA Feb. 2010. (Lummi Nation, Shoshone-Bannock Tribe and the Swinomish Tribe are eligible to 

adopt tribal water quality for their respective reservations.)

Lake Washington r Anglers rate 10.8 g/day; angler 95th percentile 30.2 g/day; children anglers 9.5 g/day with 95th percentile 86.2 g/day. Allowable meal limits 

determined for northern pikeminnow, yellow perch, cutthroat trout, sockeye salmon.
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Table Sources:

a. CRITFC, 1994.

b. Toy et al., 1996.

c. The Suquamish Tribe, 2000.

d. Sechena et al., 1999.

e. Kissinger, 2005.

f. U.S. EPA, 2002a.

g. Windward Environmental, 2007.

h. Lower Elwha Klallam Tribe, 2007.

i. Lower Elwha Klallam Tribe, 2008.

j. Washington DOH, 1997.

k. Naval Facilities Engineering Command Northwest, 2010.

l. Washington DOH, 2001.

m. U.S. EPA, 2006.

n. U.S. Department of the Interior, Fish and Wildlife Service, 1994.

o. ATSDR, 2009.

p. Washington DOH, 2010.

q. U.S. EPA, 2011b.

r. Washington DOH, 2004.
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4.7 Key Findings

Ecology reviewed finfish/shellfish dietary surveys and related information relevant to fishconsuming populations in Washington, including general population data from national surveys

and regional fish consumption surveys.

1. National survey data

Ecology analyzed general population survey data from national studies. A statistical 

methodology used by the National Cancer Institute (NCI) was applied to the national survey 

data to estimate long-term consumption rates from the short-term dietary records collected by 

these studies. It is noted, however, that national survey data may underestimate fish 

consumption in coastal states, such as Washington, which have large fish resources available 

for harvest and consumption. 

2. Regional survey data

Ecology identified the following Pacific Northwest tribal surveys as well-designed and wellconducted. They meet measures of technical defensibility and are directly applicable to 

Washington population groups. 

 A Fish Consumption Survey of the Umatilla, Nez Perce, Yakama, and Warm Springs 

Tribes of the Columbia River Basin (CRITFC, 1994).

 A Fish Consumption Survey of the Tulalip and Squaxin Island Tribes of the Puget Sound 

Region (Toy et al., 1996).

 Fish Consumption Survey of the Suquamish Indian Tribe of the Port Madison Indian 

Reservations, Puget Sound Region (The Suquamish Tribe, 2000).

These surveys provide finfish and shellfish dietary information for Washington fish-consuming 

populations and identify and quantify consumption habits. Ecology believes that these surveys 

provide credible information about fish consumption in Washington.. 

3. Asian and Pacific Islander survey data

The Asian and Pacific Islander Seafood Consumption Study (Sechena et al., 1999, including EPA’s 

2005 re-evaluation) is well-designed and conducted, but represents only a very small sample of 

each of the Asian and Pacific Islander populations surveyed. Because of the differences in API 

populations across the state, it may not be appropriate to apply these results statewide. 

4. Recreational survey data

Recreational fish consumption surveys conducted in Washington were generally older and 

were conducted using less technically defensible methods (creel surveys). 
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Ecology has reviewed other surveys and fish consumption information used for health 

assessments for specific populations groups and water bodies throughout Washington State (see 

Appendix B). Although these surveys are technically sound and help support an evaluation and 

assessment of potential adverse effects from consuming contaminated fish from specific water 

bodies, their methodology does not allow for the projection of longer term estimates of fish 

consumption. Hence, these estimates are tabulated in this chapter to provide multiple lines of 

evidence, as a weight-of-evidence approach, that people in Washington State harvest and 

consume large amounts of fish. 

Fish consumption rates for the general population and from the three Pacific Northwest tribal 

surveys identified above are listed in Table 33 below. The dietary survey methodologies 

employed for these studies are well documented and provide quantifiable dietary information.

Ecology applied measures of technical defensibility to these fish dietary surveys to assess their 

suitability for estimating long-term fish consumption rates for Washington State fish-consuming 

populations. Ecology believes that these surveys provide credible information about fish 

consumption in Washington.

Table 33. Summary of Fish Consumption Rates from Studies Meeting the 

Measures of Technical Defensibility, All Finfish and Shellfish (g/day)

Population Source of Fish

Number of 

Adults 

Surveyed

Mean

Percentiles

50th 75th 90th 95th

General population

(consumers only)

All sources: EPA method 2,853 56 38 79 128 168

All sources: NCI method 6,465 19 13 25 43 57

Columbia River Tribes All sources 464 63 41 65 130 194

Columbia River – 56 36 57 114 171

Tulalip Tribes All sources 73 82 45 94 193 268

Puget Sound 71 60 30 75 139 237

Squaxin Island Tribe All sources 117 84 45 94 206 280

Puget Sound – 56 30 63 139 189

Suquamish Tribe All sources 92 214 132 284 489 797

Puget Sound 91 165 58 221 397 767

See also Polissar et al., 2012 

Discussion

Based on the fish dietary surveys for Puget Sound and the Columbia River basin, fish-consuming 

populations within the Pacific Northwest consume comparable amounts of fish. The average fish 

consumption rates from all sources for the Columbia River, Tulalip, and Squaxin Island tribes 

are within a very small range of one another, about 60 to 80 g/day. Central tendency estimates of 

consumption, either average or median estimates, for Asian-Pacific Islanders, recreational 

anglers, and national (based on EPA information) estimates are also within this range. Fish 

consumption estimates from local harvests for tribal fish-consuming populations show a similar 
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but slightly lower trend, around 55 to 60 g/day. The Puget Sound fish-consuming population that 

consumes the largest amount of fish is the Squamish Tribe, with higher central tendency 

estimates of consumption of about 130 to 215 g/day. For these fish-consuming populations, the 

trend for the upper 90th and 95th percentile fish consumption estimates shows a convergence that 

illustrates a consistently high rate of fish consumption.

Figure 12. Regional-specific Adult Fish Consumption Rates, Harvested from All 

Sources

Figure 13. Regional-specific Adult Fish Consumption Rates, Harvested from 

Local Sources

65

94

94.4

284

194

268

280

797

0 100 200 300 400 500 600 700 800

Columbia R

Tulalip

Squaxin Island

Suquamish

grams/day

95th %ile

90th %ile

75th %ile

Mean

57

75

63

221

171

237

189

767

0 100 200 300 400 500 600 700 800

Columbia R

Tulalip

Squaxin Island

Suquamish

grams/day

95th %ile

90th %ile

75th %ile

Mean

(See Table 33)

(See Table 33)
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Computations for all percent estimates of local fish harvests are based on estimates of fish 

consumption for tribal populations from Table 33. Percent estimates are derived based on upper 

percentile estimates of fish consumption from all sources compared with sources of fish 

harvested locally, such as Puget Sound or the Columbia River basin.

For all fish consumed. About 67 to 68 percent of total fish consumed by the Squaxin Island 

tribal population are locally harvested. The percentage of total fish consumed that is locally 

harvested is somewhat higher for the other tribal populations surveyed: approximately 88 percent 

for the Columbia River Tribes, 72 to 88 percent for the Tulalip Tribe, and 81 to 96 percent for 

the Suquamish Tribe. 

Table 34. Percent of Tribal Fish Consumption Rate (All Sources)

that is Locally Harvested

Population At the 90th Percentile At the 95th Percentile

Columbia River Tribes 88% 88%

Tulalip Tribes 72% 88%

Squaxin Island Tribe 67% 68%

Suquamish Tribe 81% 96%

For anadromous fish consumed. About 72 to 77 percent of anadromous fish consumed by the 

Tulalip tribal population are locally harvested. The percentage of anadromous fish consumed that 

is locally harvested is somewhat higher for the other tribal populations surveyed: approximately 

88 to 89 percent for the Columbia River Tribes, and 80 percent for the Squaxin Island Tribe. 

Insufficient data were available on locally harvested anadromous fish consumption for the 

Suquamish Tribe. 

Table 35. Percent of Tribal Anadromous Fish Consumption Rate

(All Sources) that is Locally Harvested

Population At the 90th Percentile At the 95th Percentile

Columbia River Tribes 88% 89%

Tulalip Tribes 72% 77%

Squaxin Island Tribe 80% 80%

Suquamish Tribe NA NA

For shellfish consumed. About 62 to 63 percent of shellfish consumed by Squaxin Island tribal 

populations are locally harvested. The percentage of shellfish that is locally harvested is 

somewhat higher for the Suquamish Tribe (81 percent), and highest for the Tulalip Tribes (98 to 

over 99 percent). 
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Table 36. Percent of Tribal Shellfish Consumption (All Sources)

that is Locally Harvested

Percent of tribal shellfish consumption (all sources) that is locally harvested

Population At the 90th Percentile At the 95th Percentile

Columbia River Tribes NA NA

Tulalip Tribes 98% >99%

Squaxin Island Tribe 63% 62%

Suquamish Tribe 81% 81%
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Chapter 5: Sources of Uncertainty

and Variability

Ecology and other agencies regularly use available scientific information on finfish and shellfish 

consumption rates to support regulatory decisions. In these situations, Ecology must generally 

select a particular value from a range of values. When making these decisions, it is appropriate to 

identify, recognize, and consider both the uncertainties associated with available data and the 

variability across individuals, fish species, and geographic areas. 

Sometimes these two terms, uncertainty and variability, are lumped together. However, the 

nature of the errors (and consequences of over- or underestimating results) that arise due to 

uncertainty in the data is different than those errors that arise as a result of variability across 

populations, geographic areas, and time. Environmental agencies’ responses to uncertainty are 

inherently different than responses to variability. Specifically:

 Variability. With variability, people and organizations know that there is a range of 

actual values for the parameter in question. In these situations, environmental agencies 

must simply decide how to characterize the range of values. 

 Uncertainty. With uncertainty, people and organizations have limited knowledge on the 

magnitude and range of the parameter in question. In these situations, environmental 

agencies must decide how to address gaps in information and/or scientific knowledge. 

This chapter summarizes important sources of uncertainty and variability in the scientific 

information used to estimate finfish and shellfish consumption rates. 

 Uncertainty associated with dietary intake survey methods.

 Variability in consumption rates for individuals within a specific study population.

 Geographic variations and uncertainties associated with extrapolating survey results to 

different population groups and different areas.

 Temporal variability and uncertainties associated with estimating long-term exposure. 

 Uncertainties associated with estimating future consumption rates and patterns.

 Uncertainties and variability in the relationships between cooked and uncooked tissue 

weights. 

 Uncertainties and variability in sources of finfish and shellfish. 

 Temporal variability in the availability of finfish and shellfish.

This chapter is designed to provide a high-level summary. There are several excellent resources 

that provide information on general sources of uncertainty and variability in risk assessments
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(National Research Council, 1994, 2009; U.S. EPA, 2011a). In addition, other agencies and 

organizations (U.S. EPA, 2007b; Oregon DEQ, 2008; Windward Environmental, 2007) have 

evaluated sources of uncertainty and variability in fish consumption rates.40 (Much of the 

information in this chapter is directly from the sources cited.) See also CalEPA (2001) for a 

particularly good discussion of sources of variability in fish consumption estimates. 

5.1 Survey methodology

Dietary recall surveys are dependent on many factors, and the careful design and execution can 

minimize or eliminate sources of certain types of errors. 

Chapter 3 discusses survey methodology, execution, publication of results, applicability and 

utility for regulatory decision making, and overall technical suitability to support regulatory 

decision making. Fish consumption surveys selected as applicable to Washington fish consumers 

were evaluated in Chapter 4. 

Factors contributing to measurement error and bias include:

 Survey design (for example, accurate representation of the target population). Considers 

attributes of the survey relative to attaining accuracy and precision (e.g., are all species 

included, are visual aids utilized for portion sizes, will the survey be administered over an 

entire fishing season, are an appropriate number of individuals interviewed).

 Survey methodology (for example, considers the interaction between the survey 

methodology chosen and attributes of the target population taking into account literacy, 

language barriers, and cultural sensitivity).

 Survey execution (for example, coding errors, interviewer bias, recall bias).41

 Method of analysis (for example, if and how systematic error is identified and estimated; 

treatment of outliers and weighting factors).

Various survey types have inherent biases, strengths, and weaknesses that may contribute to 

variable results demonstrated across these different surveys. It should be noted that regulatory 

policies (for example, what questions are the surveys designed to answer) can influence the 

planning and design phases, which can in turn influence the results and conclusions. 

Furthermore, policy choices may not be consistent across various federal and state agencies and 

academic institutions. 

 

40 See also the National Cancer Institute discussions of measurement error related to dietary surveys. 

http://riskfactor.cancer.gov/measurementerror/

41 Recall bias occurs when factors exist that may affect the respondent’s memory of an event. For example, an individual that consumed fish in 

the last 24 hours may provide greater estimates of fish consumption on a seasonal or yearly basis.
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EPA examined different fish consumption survey methods, identifying important considerations 

for survey design, selection of respondents, quality assurance, and statistical analysis (U.S. EPA,

1992). Additional guidance on fish and wildlife consumption surveys thoroughly examines

survey instrument design, execution, and analysis (U.S. EPA, 1998). 

Limited resources and differing objectives for organizations and groups interested in determining 

fish consumption rates can influence the design of the survey and how it is conducted. Plausible 

objectives for fish consumption surveys include: determining average consumption rates, fishing 

pressure on water bodies, and maximum consumption during the fishing season. Surveys 

designed to meet one objective may not be suitable for another. Ecology must consider a fish 

consumption survey’s objectives, execution, and evaluation to determine the utility of a survey’s 

use by Ecology for environmental regulation. 

5.1.1 Differences due to survey design, terminology, and 

definitions

Some fish dietary surveys may not include all relevant species in the questionnaire. Terminology 

across different fish consumption surveys may be highly variable. A lack of a consistent 

terminology can contribute to variability and uncertainty. For example, shellfish usually refers to 

aquatic invertebrate organisms with a shell. Clams and oysters are easily identified as shellfish. 

However, selected aquatic animals (squid) have evolved such that the shell has become internal 

and/or reduced, while in others, the shell has disappeared (octopus). Furthermore, crustaceans 

(crayfish) have exoskeletons instead of true shells. 

Seafood consumption may include finfish and/or shellfish obtained from a variety of sources. 

Surveys may not differentiate the sources of the finfish and/or shellfish. Indeed, some surveys 

may consider consumption of fish harvested from a single water body (e.g., Commencement 

Bay) while other studies determine rates for fish consumption from multiple water bodies. Also, 

consumption rates reported in different studies may or may not distinguish between consumption 

of marine, estuarine, and freshwater finfish and shellfish. These differences and their 

contributions to variability were summarized in a study published in the Journal of Exposure 

Analysis and Environmental Epidemiology (Ebert et al., 1994). This study noted that the 

consumption rate of an individual comprises the sum of the rates from different sources. It does 

not differentiate among sources of seafood. Estimates may vary substantially depending on how 

these different sources are evaluated.

5.1.2 Types of data and methods of collection

The method used to collect dietary information may lead to uncertainty. For example, data 

collected from creel surveys involve interviewing anglers at fishing locations to provide water

body-specific data about fishing frequency, fish species, and sizes caught and/or consumed. Hence, 

the creel survey method may only provide data about specific species available during specific 

seasons. Creel surveys, like other surveys methods, are subject to biases. Poor catches, catches 
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below legal size limits, or catches above total allowable limits may not be reported. Persons fishing 

without a license may avoid participating. See Table 9 for issues associated with creel surveys.

5.1.3 Cooked and uncooked tissue weights

A number of researchers have noted the uncertainty introduced by inconsistency regarding 

reporting of finfish and shellfish using cooked vs. uncooked weight. Raw fish tissue samples are 

used to determine chemical contaminant levels for use in human health risk assessments.

The EPA Region 10 Framework recommends that risk assessments be performed using the 

weight of uncooked fish, with no modification for potential contaminant losses or gains during 

cooking. This is consistent with the fact that uncooked fish consumption rates were measured in 

the tribal finfish and shellfish consumption studies cited. EPA notes:

Because of the many ways in which fish may be served, quantitative assumptions 

regarding preparation methods and their effects on contaminant concentrations would be 

unreliable. Depending upon the preparation and cooking procedures, and upon the 

nature of the contaminants in the fish, concentrations may decrease or increase [U.S. 

EPA, 1998]. For fat-soluble compounds such as PCBs, trimming and removing adipose 

tissue reduces the mass of contaminants in the consumed portion of the fish. Similarly, 

broiling, frying, or grilling fish is likely to result in reductions of fat-soluble compounds

[Sherer and Price, 1993]. Cooking is not likely to change the level of exposure to 

mercury because it is bound to muscle tissue and is not lost by cooking, which mostly 

removes moisture and fat [Morgan et al., 1997]. Fish cooked with no prior preparation, 

as in a stew, might show negligible loss of contaminants, except perhaps for volatile 

contaminants. Because lead concentrates in bones, preparations where bones are 

discarded are likely to result in reductions in lead exposure [Ay et al., 1999].

5.1.4 Variability within a population

A number of factors may contribute to variability in finfish and shellfish consumption survey

results (Ebert et al., 1994). Dietary patterns vary within a population and between populations. 

Different population groups may have different fish consumption rates related to cultural or 

regional differences. Family preferences, recipes, and individual taste are sources of variability 

within a population; access to resources, tradition, and custom are sources of variability between 

populations. 

5.1.5 Data analysis and statistical considerations

Without careful definition of the target population, it is possible to bias survey results. For 

example, to avoid characterizing the consumption for a population that is not at risk from 

consuming contaminated fish, surveys are designed to evaluate consumers only, with questions 

allowing identification of persons who never (or rarely) consume fish. 
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Various statistical techniques have been described to analyze consumption data. For example, 

different methods of treating missing data or non-response data may contribute to bias. 

Identification and treatment of potential outliers may contribute to biased datasets (this includes 

recording outliers as multiples of standard deviations above the mean or eliminating them from 

the dataset). 

Defining subgroups within a larger population (stratification) differently can affect survey results 

and introduce different levels of bias. An important element of survey design is how well the 

survey sample population represents the selected target population or population of concern. 

Weighting schemes designed to make a sample more representative of the population should be 

carefully defined. Statistical methods should consider sampling rate, differences in sampling 

days, and other factors that may influence the results. 

The fish consumption rates for a fish-consuming population should be sufficiently characterized 

to provide a population distribution and statistics that contribute to an understanding of the 

nature of a population exposure distribution such as the mean, median, and upper percentiles 

(90th or 95th percentile) or bounding estimates (99th or 99.9th percentile). It is essential to 

understand how these distributions were derived as distributions derived from consumers and 

non-consumers of fish have different meanings and applications.

It should be noted that 24-hour dietary recall surveys that include food frequency questionnaires 

enable calculating the upper percentiles with greater confidence (U.S. EPA 1992, 1998).

Consistent with federal guidance on fish dietary survey methodologies, all regional Pacific 

Northwest fish dietary surveys (Tribal and Asian-Pacific Islander populations) employ some 

permutation of a food frequency questionnaire in their survey methodology to project long-term 

consumption estimates. 

Fish dietary information may be reported as point estimates, usually a mean or median value to 

represent central tendency estimates of consumption, or as a distribution of values. When the 

estimates of fish consumption are normally distributed in a population, the mean and median will 

be close or approximately equal. When the distribution is skewed (e.g., lognormal distribution),

the mean and median may be substantially different. The mean fish consumption estimate 

represents the average value for the sampled population and in a skewed distribution the mean 

will either be a higher or lower value than the median value. For a highly positively skewed 

distribution, as found in the Pacific Northwest fish-consuming populations, the mean is higher 

than the median estimates of consumption. The median value represents the 50th percentile (or 

midpoint) of the distribution where half of the sampled population consumes more and half 

consumes less fish, than the median value (Helsel and Hirsch, 2002).
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Figure 14. Density function for a positively skewed lognormal distribution

5.1.6 Target populations and characteristics of populations

Different population groups may have different fish consumption rates. Recognizing differences 

between fish consumption rates for whole populations (including both consumers and nonconsumers) and consumption rates in actual consumers of fish is a critical distinction. For 

example, Oregon’s Human Health Focus Group made the clear distinction between per capita 

fish consumption based on consumers and non-consumers of fish. High fish consumers make up 

a relatively small portion of the whole population, and may represent extreme upper percentiles 

in a distribution that includes both consumers and non-consumers of fish. 

A distinction is generally made between (a) national per capita consumption estimates inclusive 

of both consumers and nonconsumers of fish and (b) estimates of fish consumption from local 

fish consuming populations (EPA Region-10 Framework, 2007; EPA, 2000; CalEPA, 2001; 

Oregon DEQ HHFG Report, 2008):

 “Per capita rates are primarily useful for trend analyses rather than representing actual 

consumption. Average per capita rates derived from national surveys for consumption of 

fish and shellfish by the general population ranged from 10 to 17.9 grams per day. Several 

analyses of data used to estimate per capita consumption of fish and shellfish found an 
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increase of approximately 25% between 1970 and the early 1990s, indicating that the U.S. 

population as a whole consumed more fish in more recent years” (CalEPA, 2001, page 3).

 “Consumption rates derived for consumers are preferable to per capita rate for use in 

describing actual consumption of fish and shellfish in the U.S.” (CalEPA, 2001, page 3).

Further distinctions are made between national per capita fish consumption estimates and 

consumer-only estimates by how consumers of fish and/or shellfish are defined. CalEPA, 2001, 

provides further insights regarding consumption estimates for populations that consume fish 

compared to estimates for the general national population as follows:

Rates reported for the general national population, usually referred to as per capita 

rates, differ from those reported for subpopulations such as individuals who catch and 

consume their own catch of fish and shellfish. It is essential to consider whether rates 

that apply on a per capita basis are appropriate to the study question or whether rates 

specific to particular subpopulations are needed. For example, some consumption rates 

have been derived by averaging over both consumers and nonconsumers, as compared to 

consumers only. These per capita estimates would not be representative of consumption 

by actual consumers or other specific subpopulations. Thus, exposure assessments and 

evaluation of potential risks to consumers must consider consumption rates appropriate 

for actual consumers.

For groups of individuals who consume sport fish and/or shellfish, there is a continuum 

ranging from intermittent fishers, who may eat fish only occasionally, to those who fish 

regularly and/or heavily and consume large quantities of the fish that they catch. These 

“high-end consumers” could include recreational fishers with high rates of success and 

subsistence fishers who rely on their catch to feed themselves and their families. 

Therefore, within the subset of the population that fishes (i.e., fishers) there is likely to be 

a wide range of fishing effort and success, and a single value is unlikely to adequately 

describe consumption by the entire fishing population (CalEPA, 2001, page 13).

5.2 Geographic differences

5.2.1 Variation and uncertainty associated with regional differences

Fish consumption surveys conducted across the United States have shown regional variations. 

There are differences between coastal areas and inland areas and regional preferences for certain 

types of finfish and/or shellfish. Local variations in climate, fishing regulations, accessibility to 

fisheries, and seasonal differences in availability of fish contribute to the variability in reported 

fish consumption rates (Ebert et al., 1994; Moya et al., 2008). Differences in habitat may be 

relevant (U.S. EPA, 2007b).
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Comparing the results of surveys from different geographic locations, each with regional effects 

plus different methodologies, time frames, or other different survey design elements, makes the 

interpretation of differences between surveys problematic.

5.2.2 Uncertainty associated with extrapolating survey results to 

different population groups and different locations

The use of surrogate consumption rates can misrepresent actual finfish and shellfish consumption 

rates. For example, Puget Sound-harvested finfish and shellfish consumption rates derived using 

Tulalip and Suquamish tribal data as a surrogate for another tribe could lead to either an 

overestimate or an underestimate of the actual finfish and shellfish consumption.

For many reasons populations surveyed in a particular study may eat different quantities and ratios 

of finfish and shellfish than do those who harvest elsewhere. For example, differences in habitat 

type and quality between fishing grounds can affect the quantity of finfish and shellfish available 

for harvest.

The EPA Region 10 framework takes this into account. For purposes of the framework, if certain 

species or types of finfish and shellfish are not present, or will not be present in the future, tribal 

members are assumed to substitute other species or types of finfish or shellfish that may be 

equally affected by the site. This assumption of resource switching among local finfish and 

shellfish is incorporated into the framework by holding constant the total amount of finfish and 

shellfish consumed. 

EPA’s policy decision to assume that resource switching occurs is supported by limited data and 

examples in Puget Sound. For example, individuals in the Suquamish Tribe study (The 

Suquamish Tribe, 2000) eat “more geoduck now, because they are more available to us, but we 

used to dry oysters and clams....” Two other respondents reported “reduced consumption of 

butter clams, cockles, and other clams and shellfish due to pollution,” but that this “reduced 

consumption was offset by the higher availability of geoducks from the Suquamish Tribe.” 

Resource switching has been documented in other areas affected by contamination, such as 

Alaska (Fall and Utermohle, 1999). 

The use of fisheries resources is important to tribes for economic, dietary, and cultural reasons. 

Tribes will likely use whatever fisheries resources are available to them. 

The following observation is made in the National Environmental Justice Advisory Council 

Meeting report (U.S. EPA, 2002b): 

For many communities of color, low-income communities, Tribes, and other indigenous 

peoples, there are no real alternatives to eating and using fish, aquatic plants, and 

wildlife. For members of these groups it is entirely impractical to “switch” to 

“substitutes” when the fish and other resources on which they rely have become 
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contaminated. There are numerous and often insurmountable obstacles to seeking 

alternatives (e.g., fishing “elsewhere,” throwing back “undesirable” species of fish, 

adopting different preparation methods, or substituting beef, chicken or tofu). For some, 

not fishing and not eating fish are unimaginable for cultural, traditional, or religious 

reasons. For the fishing peoples of the Pacific Northwest, for example, fish and fishing 

are necessary for survival as a people – they are vital as a matter of cultural flourishing 

and self-determination.

If certain types of finfish or shellfish preferred by tribal members are not present in their usual 

and accustomed areas, the framework assumes that tribal members will substitute alternative 

local types of finfish or shellfish in their diets, generally within the same category of fish or 

shellfish. Thus, the total consumption rate remains the same, regardless of the availability of a 

particular type of finfish or shellfish. This is a reasonable and protective assumption for tribal 

members who, for economic, ceremonial, religious, or personal preference reasons, are likely to 

substitute one species for another. 

The assumption that resources will be switched is likely to result in an overestimate of risks for 

other tribal members who may decrease their overall finfish and shellfish consumption rate 

because their preferred types are unavailable. Risks may be underestimated if the actual dietary 

practices of a tribe would result in consumption of species that have higher contaminant levels 

than the preferred or assumed types of finfish or shellfish.

5.2.3 Availability of finfish and shellfish

The abundance of finfish and shellfish resources available to a given population may be a source 

of uncertainty. Different water bodies vary in their capacity to support and sustain different 

species of finfish and shellfish. Furthermore, the capacity of the water body to support fish 

resources may change over time, for both natural and human caused reasons. 

Regarding the use of surrogate data, the EPA Region 10 framework notes:

Although the degree to which site-related risks could be overestimated by the use of any 

of the fish and shellfish consumption rates presented in this Framework cannot be known 

precisely, these methods are preferable to alternatives that would be likely to 

underestimate site-related risks, such as basing a consumption rate (or site-related 

estimates of risk) on the size of the cleanup site, or reducing the site’s estimated 

contribution to fish and shellfish contamination because nearby sites or sources are 

associated with similar contaminants. This Framework includes the assumption that the 

selected Tribal fish and shellfish consumption rates and their associated risk estimates 

will not be reduced based on consideration of the size of the cleanup site or the presence 

of additional sources of contamination.
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The use of a consumption rate based on all finfish and shellfish harvested from Puget Sound as a 

surrogate for a consumption rate based on finfish and shellfish affected by a cleanup site is likely 

to overestimate the risk of eating finfish and shellfish from the site, since only a portion of the 

finfish and shellfish diet will have actually come from the site in question. The degree of 

overestimation depends upon such factors as size and location of the site, type and degree of 

contamination, and habits of affected finfish and shellfish. 

A potential data gap is the lack of information on commercial routes of distribution for locally 

harvested fish and/or shellfish to local food markets, restaurants, or other food outlets in 

Washington State. However, seafood supply availability as an indirect measure of consumption 

has very limited utility. As noted by CalEPA, 2001 (page 15):

Approaches to collecting data on fish consumption include both indirect and direct 

measures. Indirect measures primarily rely on data pertaining to food availability or 

food disappearance into marketing channels or households, and are best regarded as a 

measure of food availability into commercial markets and only a rough indicator of 

consumption. Data from studies on food availability generally have been collected for 

purposes other than to estimate consumption rates, and data gaps are most serious at the 

level of the individual consumer; therefore, these types of data are inappropriate for 

estimating consumption rates for consumers (Anderson, 1986; U.S. EPA, 1992). 

Additionally, food availability data do not account for waste or spoilage, and 

interpretation of the results is highly specialized; however, the results from these types of 

surveys can be useful to assess trends over time (Anderson, 1986). 

On the other hand, some of the finfish and shellfish consumed in restaurants or obtained in 

grocery stores may have been harvested in Puget Sound, which could lead to an underestimate of 

exposure. 

5.3 Temporal uncertainty and variability

Although estimates of consumption using short-term dietary recall may be reported as g/day, the 

values may not be the same as long-term consumption rates averaged over time and presented as 

a daily rate. Study methodologies that consider fish consumption over a longer period of time 

may be more likely to represent the fish consumption patterns of the population studied.

5.3.1 Using short-term data to estimate long-term exposure

Current health risk models are designed to evaluate health risks associated with exposure over 

long periods of time. Risk assessors typically use the results from short-term dietary surveys to 

characterize the amounts of finfish and shellfish eaten on a regular basis over longer periods of 

time intervals (years).
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This approach works well when average values are used in the health risk model. However, 

regulatory approaches based on concepts like reasonable maximum exposure are typically based 

on the use of upper percentile values (e.g., 90th percentile or above). In this situation, the use of 

short-term survey results is complicated because the distribution of estimated fish consumption 

rates over a short period of time will be more spread out than the actual fish consumption over a 

longer period of time. This means that estimates of the 95th percentile of the fish consumption 

rates observed over a short period of time (one or two days) will be higher than the 95th

percentile of the average daily fish consumption over the longer periods of time considered in 

health risk assessments (years). This narrowing of the distribution of estimates is called 

regression to the mean.

42

5.3.2 Temporal factors biasing estimates of fish consumption

The collection of fish consumption information may be subject to temporal biases. Use of 24-

hour recall data to estimate fish consumption rates over longer periods are subject to potential 

biases from the effects of the day of the week or seasonal variations in the availability of fish. 

Longer term estimates of fish consumption reported by individuals may be subject to recall bias. 

Rates will be overestimated if fish consumption habits are surveyed when fish are readily 

available relative to periods when fish are not readily available. Consumption data obtained on 

consecutive days may be biased due to the consumer correlation with the fish consumed on 

adjacent days. 

Recall bias for estimates of long-term fish consumption is more of an issue for populations 

where fish may be infrequently consumed and consumption patterns are episodic in nature. In 

contrast, recall bias in estimating long-term fish consumption rates is minimized for populations 

in which fish is a primary dietary protein source, is consumed frequently, and where 

consumption information is hence easily recalled. 

The timing of survey administration may or may not account for the biases introduced by seasonal 

variations in fish availability. Extrapolating estimates of long-term fish consumption from 24-

hour recall data or from evaluations of yearly fish consumption may be improved by interviewing 

fractions of the survey populations during different seasons or by re-interviewing individuals. 

Short-term estimates of food intake rates for infrequently consumed items for the general 

population (e.g., fish) from national short-term surveys are bimodal, varying between zero and 

the amount typically consumed at a meal. This results in an overestimate of the prevalence of 

 

42 Regression to the mean is encountered in many areas of science and everyday life. For example, baseball batting averages have a much 

larger distribution early in the season compared to the end of the season. The following case study illustrates the implications of this situation. 

There were 177 major league players with at least 400 plate appearances during the 2011 season. Consider the players’ batting averages after 

their first game and at the end of the 162 game season. The first day estimates for the median and average provide a reasonably good 

estimate of those values for the whole season. However, the first day estimates for the 90th and 95th percentiles of the distribution of batting 

averages are much higher than the end-of-the season values. As with many situations, players who did extremely well on the first day of the 

season also had days where they were hitless. Conversely, players who went hitless on opening day had games later in the season where they 

had one or more hits.
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low and high intake rates relative to those that would be seen over a longer observation period.

This variation is particularly relevant for assessments of food chemical exposure where the 

parameters of interest are at the extremes of the exposure distribution rather than at the center

(Lambe, 2002). 

Attempts to account for the variability and uncertainty associated with the use of short-term 

consumption studies have generally included qualitative evaluation of data from a range of 

sources, coupled with consideration of the intended use of the data. To evaluate long-term 

(habitual) seafood intake, longer-term survey data are preferable to short-term dietary survey data. 

Ecology conducted a statistical reanalysis of short-term national fish consumption data to 

estimate long-term (usual) national fish consumption rates, using the methodology of Tooze

et al., 2006 (as cited in Polissar et al., 2012). National fish consumption rate estimates based on 

this reanalysis are significantly lower than estimates based on simple extrapolation of the shortterm fish consumption data. See also the Technical Issue Paper, Estimating Annual Fish 

Consumption Rates Using Data from Short-term Surveys (Ecology, 2012). 

5.3.3 Issues using currently suppressed fish consumption data to 

predict future fish consumption

The presence (or absence) of finfish and shellfish adversely affected by site-related 

contamination could suppress consumption rates observed during surveys.

The Oregon DEQ Human Health Focus Group discussed some of the factors that may contribute 

to depressing fish consumption rates compared to historic rates. They noted (1) significant 

reductions in fish populations, (2) the belief that fish that reside in polluted waters will 

bioconcentrate pollutants and are contaminated and unsafe to eat, and (3) the intended impact of 

local fish advisories or the unintended consequences of national fish advisories of commercial 

fish species that are not applicable to local waters.

The Human Health Focus Group also noted that some studies excluded or discounted high fish 

consumers by identifying them as statistical outliers. This would have the effect of 

underestimating the true range in fish consumption rates. If the rates are already suppressed, the 

elimination of the highest values may be reporting an artificially low fish consumption rate.

Where tribal members have already reduced their harvest of finfish and shellfish from impaired 

habitat, the use of current consumption rates could result in underestimations of potential finfish 

and shellfish consumption rates. As noted in the National Environmental Justice Advisory

Council Meeting report (U.S. EPA, 2002b): 

A suppression effect occurs when a fish consumption rate for a given subpopulation 

reflects a current level of consumption that is artificially diminished from an appropriate 

baseline level of consumption for that subpopulation . . . When agencies set environmental 

standards using a fish consumption rate based upon an artificially diminished 
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consumption level, they may set in motion a downward spiral whereby the resulting 

standards permit further contamination and/or depletion of the fish and aquatic resources. 

Cleanup levels in the local aquatic environment, if they are based on current finfish and shellfish 

consumption rates in the vicinity of the cleanup site, may not reflect the potential for the water 

body to rebound from its current, relatively contaminated state. This should be considered when 

deciding whether the use of a surrogate tribal finfish and shellfish consumption rate would better 

represent potential future consumption rates than would consumption rates that represent only 

current or near-term contamination and habitat conditions.

Studies indicate that tribal fish consumption rates are suppressed compared with historical rates 

and presumable rates that would exist given historical fishing stocks. The recommendations in 

this report, however, were developed using existing data from published studies. 

For Native American populations in Washington, evaluating fish consumption rates using 

common survey methodology may be problematic (Donatuto and Harper, 2008). Surveys and the 

exposure models they develop provide information only about current consumption patterns. The 

number of tribal members practicing traditional lifestyles is below known historical levels. 

Survey data do not provide information on historical fish consumption rates and resource use, 

which may be more indicative of consumption rates. 

Researchers suggest that suppression happens for various reasons (Donatuto and Harper, 2008). 

Two reasons are contamination and lower abundance. When the fish are contaminated or absent, 

tribal members may eat less fish and/or substitute other types of fish. While, historically, fish 

provided the main dietary source of protein, this is true today for only a small subset of the tribal 

population (Harper et al., 2007; Harper and Harris, 2008; Harris and Harper, 2001). Tribal health 

experts suggest that current tribal fish consumption rates are suppressed due to diminished access 

to historical quantities of finfish and shellfish, and some researchers believe that historical rates 

represent the appropriate baseline level of consumption. Effects of suppression due to chemical 

contamination should be accounted for in environmental cleanup regulations. However, 

accounting for suppression in environmental cleanup regulations may be problematic when 

suppression is due to permanent loss or modification of habitat due to urban infrastructure. 

Where habitat can be restored, then environmental cleanup regulations need to account for 

suppression effects in revising fish consumption estimates to help support cleanup decisions.

5.4 Uncertainty in Pacific Northwest fishconsuming populations

Ecology has identified numerous fish dietary surveys in Washington State that reflect high rates 

of consumption for certain ethnic groups (CRITFC, 1994; Toy et al., 1996; Sechena et al., 1999; 

The Suquamish Tribe, 2000). Consumption estimates vary among subpopulations by age, sex, 

mode of harvesting, and by region within Washington State. Washington State fish-consuming 
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populations have been identified (tribal populations, Asian-Pacific Islanders, recreational fishers) 

and levels of consumption have been estimated from these surveyed populations. These higher 

fish-consuming ethnic populations and other high-end fish consumers are represented by upper 

percentile consumption estimates (90th and 95th percentile) derived from distributional analysis of 

the fish dietary data (CalEPA, 2001; Polissar et al., 2012). 

Many of the Pacific Northwest regional-specific surveys note differences in patterns of fish 

consumption (e.g., eating different fish parts) and fish harvesting techniques, which demonstrates a 

level of variability across and among these fish-consuming populations (CalEPA, 2001; CRITFC, 

1994; Toy et al., 1996; Sechena et al., 1999; The Suquamish Tribe, 2000; EPA EFH, 2011). Central 

tendency estimates of consumption for these populations are very similar (all fish from local 

harvests) with upper percentile estimates (90th and 95th percentile) within an order of magnitude.

There is considerable uncertainty inherent in evaluating and estimating fish consumption rates 

for northwest fish-consuming populations. Much of the uncertainty is because the available 

information, although substantial, nonetheless provides only a partial picture of fish consumers 

in Washington. Sources of uncertainties can include the following:

 Whether the available surveys provide a complete picture of the variety of fish 

consumption practices among various fish consuming populations. 

 Evolving and changing lifestyle patterns for various populations across the state. 

 Data gaps around dietary habits for other potentially high fish-consuming populations; 

for example, various ethnic groups, pescadarians (people who eat fish but not meat), 

subsistence fishers, and low income groups.

 Using information about one group as a surrogate for another group’s consumption rate

based on evaluation of the similarity or differences in, say, species available or the extent 

of local shellfish habitat. 

 The degree to which lifestyle (ethnic, tribal, subsistence, etc.) is recognized and 

accounted for in consumption studies. 

 Whether or how information from the national fish dietary dataset may be inadequate for 

understanding fish consumption along coastal states with significant fishery resources. 

 Whether and how a particular study addresses consumption of anadromous fish species.

It is expected that as the body of information grows some of these data gaps will be filled and 

uncertainty about Pacific Northwest fish-consuming populations will decrease. 
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Chapter 6: Using Scientific Data to Support 

Regulatory Decisions

The purpose of this Technical Support Document (Version 2.0) is to compile and evaluate available 

information on fish consumption in Washington State. There are risk management issues related to 

regulatory decisions based on this information. This is a technical document; it is not designed to 

resolve policy issues associated with using that information to make regulatory decisions. Ecology 

will be considering those issues in separate documents and processes.

This chapter is intended to provide context. It offers a brief introduction for people who are 

interested in the multiple and interrelated questions that arise during regulatory decision making. 

The Conservation Foundation has stated that it is important that environmental agencies 

distinguish between scientific and policy choices when making regulatory decisions

(Conservation Foundation, 1984, p. 310): 

A key to understanding the risk assessment process is to distinguish between those 

aspects of the process that are scientific and those that are matters of policy or 

personal values, and to appreciate their complex interrelationships .... A risk 

assessment process that is defensible from both a scientific and a policy 

standpoint must accurately identify which aspects of the assessment are policy 

and which are science. The difficulty is that both scientists and policy makers tend 

to define their realm in the broadest terms. 

The interaction between science and policy in regulatory decision making is complicated. 

Several equally valid scientific options may resolve a particular issue. In these situations, the 

regulatory decision essentially represents a policy choice that must take into account statutory 

directives, implementation issues, and value judgments on how to deal with scientific uncertainty 

and variability in exposure and susceptibility. As Victor Hugo once wrote, “Science says the first 

word on everything, and the last word on nothing,” (Hugo and O’Rourke, 1907). 

Chapters 4 and 5 of this report provide Ecology’s evaluation and conclusions regarding current 

scientific information on fish consumption rates in the Pacific Northwest. As the wealth of 

knowledge continues to grow, additional information will be available in the future. Sciencebased regulations may have built-in requirements to periodically review and update standards 

based on new information. This chapter highlights some of the policy choices that will be needed 

when using this information to support regulatory decisions. The chapter is organized into 

sections. Each section provides a brief description of a particular regulatory issue and a range of 

examples to illustrate how agencies have resolved that issue. The issues are:
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 Population groups.

 Individual variability in fish consumption rates.

 Geographic variations in fish consumption rates.

 How anadromous species (e.g., salmon) are included in fish consumption rates used for 

environmental regulation.

 Locally caught vs. store-bought finfish and shellfish.

 Development of regulatory fish consumption rate estimates from consumer-only vs. per 

capita surveys.

 Other exposure factors (e.g., body weight and exposure duration).

 Acceptable risk.

This is a partial list. Other issues may hold equal or greater importance for particular decisions. 

In addition, agencies typically do not consider individual policy choices in isolation from other 

choices. In other words, a decision on one issue may impact the decisions on other issues. For

example, decisions on what constitutes an acceptable level of risk may influence decisions on 

how to address the uncertainties and variability in fish consumption rates. 

6.1 Population groups

When developing a regulatory standard based on health protection, agencies must decide what 

population groups that standard is designed to protect. This is a policy choice that can be made on 

a programmatic (or statewide) or site-specific basis. This choice can have large implications given 

the differences in fish consumption rates calculated using information summarized in Chapter 4. 

This policy choice is influenced by many factors including statutory requirements, environmental 

equity, and the nature of the decision (programmatic vs. site-specific). Options typically 

considered by agencies include:

 General population. Environmental and health agencies have established regulatory 

requirements or fish advisories that are based on the amount of finfish and shellfish 

consumed by members of the general population. For example, the EPA has adopted 

guidance for implementing the Clean Water Act that includes a default fish consumption 

rate of 17.5 g/day. The data used to establish this rate include individuals who do not eat 

fish. Several states have used this value to develop state water quality standards and 

cleanup standards for individual sites. 

 Recreational anglers. Environmental and health agencies have established regulatory 

requirements or fish advisories using information on the amount of finfish and shellfish 

consumed by recreational anglers. For example, Ecology in 1991 adopted a default fish 
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consumption rate (54 g/day) in the MTCA rule that is based on a recreational fish 

consumption survey. 

 High exposure population groups. Environmental and health agencies have established 

regulatory requirements or fish advisories using information on the amount of finfish and 

shellfish consumed by members of high exposure population groups (such as Native 

Americans and Asian Pacific Islanders). For example, the Oregon DEQ has adopted a 

fish consumption rate (175 g/day) that is based on concerns about tribal populations. 

Ecology has also established sediment cleanup standards for individual sites that are 

based on assessing exposure for tribal populations.

 Susceptible populations. Environmental agencies also establish regulatory requirements 

or advisories using information on groups that are more susceptible to the effects of toxic 

chemicals (e.g., children, pregnant women). For example, EPA and DOH have issued fish 

advisories that are based on limiting mercury exposure for pregnant women. 

6.2 Individual variability in fish consumption rates

No two individuals are exactly alike. Exposure to hazardous substances is influenced by multiple 

factors and may vary widely among individuals within a given population group. Chapter 4 provides 

information on the variability in fish consumption rates in several study populations. When using 

that information to support regulatory decisions, Ecology will need to decide which values within 

this range of variability to use to characterize fish consumption, and consequently the degree of 

protectiveness Ecology offers when characterizing exposure and making regulatory decisions.

Ecology has compiled information on the distribution of fish consumption rates among the 

general population, and for participants in the three primary studies identified in the Technical 

Support Document. The study results were compiled in Table 37 below. 

Table 37. Summary of Fish Consumption Rates, All Finfish and Shellfish

Population Source of Fish

Number of 

Adults 

Surveyed

Mean

Percentiles

50th 90th 95th

General population

(consumers only)

All sources: EPA method 2,853 56 38 128 168

All sources: NCI method 6,465 19 13 43 57

Columbia River Tribes All sources 464 63 41 130 194

Columbia River – 56 36 114 171

Tulalip Tribes All sources 73 82 45 193 268

Puget Sound 71 60 30 139 237

Squaxin Island Tribe All sources 117 84 45 206 280

Puget Sound – 56 30 139 189

Suquamish Tribe All sources 92 214 132 489 797

Puget Sound 91 165 58 397 767

See Polissar et al., 2012, Table E-1. 
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Choosing a summary measure to characterize population exposure reflects an explicit (or 

implicit) policy choice on the appropriate balance between over- or underestimating exposure 

levels for particular individuals within the population group. Agencies typically choose one of 

two approaches for addressing this issue: 

 High end of the distribution. Many agencies develop standards that are based on protecting 

more highly exposed individuals within a population group. For example, state and federal 

cleanup standards are typically based on a reasonable maximum exposure (RME).43 The 

RME is defined as reasonable because it is a product of several factors that are an 

appropriate mix of average and upper-bound estimates. RME estimates typically fall 

between the 90th and 99.9th percentile of the exposure distribution. This reflects a policy 

choice that emphasizes the protection of the more highly exposed individuals in a 

population group. EPA used a similar approach when updating the Methodology for 

Deriving Ambient Water Quality Criteria for the Protection of Human Health (U.S. EPA, 

2000b). The EPA methodology provides a broader range of fish consumption rate statistics 

for tribes and states to choose from than does the Superfund (CERCLA) program. The EPA 

methodology allows for both upper percentile and central tendency policy choices. The 

Ambient Water Quality Criteria for the Protection of Human Health does include upper 

bound and central tendency exposure parameter choices that reflect an RME approach (e.g., 

90th percentile drinking water ingestion rate and an average body weight). The EPA 

methodology provides a default fish consumption rate for the general population (based on 

protection of recreational fishers). This value (17.5 g/day) reflects the 90th percentile values 

protective of consuming estuarine and freshwater fish. It is derived for adults only using 

data from the USDA’s CSFII Survey for the years 1994 to 1996. 

 Middle of the distribution. Agencies also develop standards that are based on protecting 

the “average” person in a population. Under this approach, individual exposure 

parameters are selected to represent the middle of the exposure distribution, which may 

be defined in terms of the mode, median, or mean.

44

 Ecology applied this policy option 

 

43 The MTCA Cleanup Regulation defines the RME as “the highest exposure that is reasonably expected to occur at a site under current and 

potential future site use.” The RME is designed to represent a high-end (but not worst-case) estimate of individual exposures.

44 Several scientific advisory committees (National Research Council, 1994, 2009) and scientists have discussed the use of summary statistics 

to describe variable quantities. For example, Finkel (1989) noted that “...all summary estimators of an uncertain quantity are value laden. 

Summary measures are little more than ways to interpret facts in light of a subjective calculus of the costs of error...” (pp. 436-437). He 

described several common statistical measures, which he observed will strike different balances between overestimating and underestimating 

a particular value. 

 Statistical mode (most frequently measured value), which embodies the value judgment that one should minimize the probability of 

error, without regard to its type (over- or underestimation) and magnitude. 

 Statistical median (the 50th percentile value), which embodies the value judgment that the costs of the two types of errors are exactly 

equivalent.

 Statistical mean (the average of the measure values), which embodies the value judgment that larger errors are more important than 

smaller errors independent of the direction of the error. He noted that when dealing with highly skewed distributions, the mean of the 
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when selecting many of the exposure parameters used to calculate Method C cleanup 

levels in the MTCA rule.

6.3 Geographic variability

Chapter 4 indicates that there is substantial variation in the amount of finfish and shellfish 

consumed in different parts of Washington. Several factors contribute to these variations:

 Water body characteristics. 

 Fish species (shellfish vs. finfish vs. salmon). 

 Local communities. 

Ecology believes that a certain amount of flexibility is needed to address this type of geographic 

variability. The question is where to build in the flexibility and where it is most needed. 

Flexibility is important for considering questions around current and future habitat and resource 

abundance, as well as the variability of fish species present at a site and their life cycle, including 

where contaminants are obtained. Ecology also acknowledges that some (but not all) water 

bodies are large enough to sustain moderate to high fish consumption rates. 

Agencies have several options for addressing the geographic variations in fish consumption 

rates. These options include: 

 Single statewide fish consumption rate. Regulatory agencies may adopt uniform 

statewide values that do not fully account for geographic variability in fish consumption 

rates. (For example, the current Water Quality Standards for Surface Waters are based 

upon a single fish consumption rate of 6.5 grams/day. Similarly, the MTCA Cleanup 

Regulation includes a single default fish consumption rate of 54 grams/day.) However, 

this approach ultimately requires several policy choices regarding the appropriate 

statewide value. 

 Multiple regional fish consumption rates. Regulatory agencies may adopt regulatory 

requirements that use several fish consumption rates that reflect the diversity of fish 

consumption from various water bodies in Washington. Several people who provided 

comments on Version 1.0 of this Technical Support Document recommended that 

Ecology consider this option. 

 Site-specific fish consumption rates. Regulatory agencies develop site-specific fish 

consumption rates that are used to establish regulatory requirements that are applicable to 

specific cleanup sites or dischargers. This approach can be implemented in combination 

with a default value established on a programmatic basis. As noted above, the MTCA 

 

distribution will often (but not always) fall at the upper end of the distribution. In some cases, the mean may approach the 95th

percentile of the distribution. 
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Information about salmon is discussed in 

various places throughout this Technical 

Support Document, including Chapter 4, 

Chapter 6, and Appendix C. In addition, 

a more detailed discussion of salmon is

presented in the Technical Issue Paper, 

Salmon Life History and Contaminant 

Body Burdens (Ecology, 2012). This is 

an artifact of the ongoing dialogue in 

response to comments as Ecology 

continues to consider the various 

scientific, policy, and regulatory issues.

Cleanup Regulation includes a default fish consumption rate (54 g/day) that is used to 

calculate site-specific cleanup standards. However, the rule also provides the flexibility to 

establish cleanup standards using a site-specific fish consumption rate. 

6.4 Salmon

Ecology has evaluated current information on salmon 

consumption and life cycles in Chapter 4 and Appendix C

of this report. Ecology also prepared a separate report that 

provides additional information and evaluation of this topic. 

Two main points emerged from those analyses:

 Salmon are a primary fish species consumed by 

Washington fish consumers. 

 In contrast to other species, a significant part of 

salmon body burden is potentially received in waters and from sources outside of 

individual MTCA sites or the waters of the state45 that are regulated under the Clean 

Water Act (CWA)-based criteria. 

There are several important issues associated with deciding whether and how consumption of 

salmon should be taken into account when developing default fish consumption rates used in 

regulatory decisions. Two key questions are: 

 How should the default rates take into account the consumption of fish species like 

salmon that spend much of their life outside of Washington waters? 

 How should the complex life cycle and biology of the different anadromous species like 

salmon be considered when making regulatory decisions?

Several different approaches are available for resolving these questions. Although others exist, 

options typically considered by state and federal agencies include:

 Salmon considered. Some agencies have established regulatory requirements that are 

based on fish consumption rates that take into account consumption of all types of finfish 

and shellfish. In other words, the regulatory requirement is based on a fish consumption 

rate that includes finfish, shellfish, and anadromous fish. For example, the Oregon DEQ 

has adopted a fish consumption rate (175 g/day) that includes salmon. 

 Salmon considered when establishing regional rates. Ecology could establish regional 

fish consumption rates that reflect the diversity of water bodies, species, and fish 

consumption patterns. Under this approach, Ecology could include salmon in the rates 

 

45 Waters of the state include lakes, rivers, ponds, streams, inland waters, underground waters, salt waters, and all other surface waters and 

watercourses within the jurisdiction of the state of Washington (RCW 90.48.020).
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applicable to some water bodies while excluding salmon in the rates for other water 

bodies. Ecology is not aware of examples where this approach has been used. 

 Salmon considered when establishing site-specific rates. Ecology could establish sitespecific fish consumption rates that include salmon for some (but not all) cleanup sites. 

Under this approach, Ecology would consider the cleanup site’s contribution to salmon 

body burden when establishing site-specific cleanup standards. 

 Salmon NOT considered. Some agencies have established regulatory requirements that 

are based on fish consumption rates that do not include salmon. For example, the EPA 

used this approach when establishing the default fish consumption rates that are included 

in the EPA Region 10 framework. Most states have adopted human health-based water 

quality criteria that do not include anadromous salmon in the fish consumption rate. 

6.5 Sources of finfish/shellfish

In some surveys, people are asked to provide information on the source of the finfish and shellfish 

they have consumed. Sources of finfish and shellfish are generally categorized as self-harvested or 

purchased from stores or restaurants. Not all locally harvested fish may be affected by site-specific 

contamination. Chapter 4 summarizes information from the four key regional fish consumption 

surveys conducted in the Pacific Northwest. Section 4.7 summarizes available information on the 

source of finfish and shellfish. For these tribal populations, locally or regionally harvested finfish 

and shellfish represents 67 to 96 percent of total finfish and shellfish consumed.

Several different approaches are used by federal and state regulatory programs to account for 

patterns of exposure from different sources. Options typically considered by agencies include: 

 Fish consumption rates based on consumption of all finfish and shellfish. Some agencies 

establish default and site-specific fish consumption rates using study results that reflect 

the total amount of finfish and shellfish consumed by study participants (independent of 

whether the finfish/shellfish were locally harvested or store-bought). For example, the 

Oregon DEQ used this approach when they revised Oregon’s Water Quality Standards

for Surface Waters. 

 Fish consumption rates based on consumption of locally harvested finfish and shellfish.

Some agencies establish default and site-specific fish consumption rates using study 

results that reflect locally harvested finfish and shellfish consumed by study participants.

For example, the EPA Region 10 framework explicitly recognizes source contribution 

issues by adjusting total fish consumption rates to account for fish harvested and 

consumed from Puget Sound (U.S. EPA, 2007b). 

 Fish diet fraction. Some agencies make site-specific adjustments to account for the 

amount of locally harvested finfish and shellfish caught at or near an individual sediment 

cleanup site. For example, the MTCA rule currently considers the fish diet fraction when 
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calculating site-specific surface water cleanup standards. The fish diet fraction is defined 

in the MTCA rule as “....the percentage of the total finfish and/or shellfish in an 

individual’s diet that is obtained or has the potential to be obtained from the site” (WAC 

173-340-708(10)(b)). Applying the 0.5 default fish diet fraction under MTCA to the 54 

g/day default fish consumption rate (see Figures 15 and 16) results in an effective fish 

consumption rate of 27 g/day.

6.6 Consumer vs. per capita

Fish consumption surveys typically include people who eat fish and people who don’t eat fish. 

People who don’t eat fish are termed non-consumers. Those that do eat fish are considered 

consumers. The proportion of non-consumers included in the survey will vary depending on the 

population being interviewed. 

The results from fish consumption surveys can be reported in terms of consumer-only rates and 

per capita rates. Consumer-only intake rates refer to the quantity of finfish and shellfish 

consumed by individuals during the survey period. These data are generated by averaging intake 

across only the individuals in the survey who consumed finfish and shellfish during the survey 

period. Per capita intake rates are generated by averaging intake rates over the entire survey 

population (including those individuals that reported no intake).

There can be large differences in study results reported on a consumer-only and per-capita basis 

when a large percentage of study participants report that they did not eat any finfish or shellfish 

during the survey period. For example, EPA evaluated national data from approximately 20,000 

individuals (3 years and older). Approximately 28 percent were fish consumers. When expressed 

on a per-capita basis, the 90th percentile of the reported results was 17.5 g/day. When expressed on 

a consumer-only basis, the 90th percentile of the reported results was 250 g/day (U.S. EPA, 2002a). 

However, there are much smaller differences in studies where a high percentage of study 

participants reported they ate some amount of fish during the survey period. For example, the 

per-capita and consumer-only rates from the CRITFC study are virtually identical. 

Federal and state environmental agencies have used both types of information to establish 

regulatory requirements. Options include: 

 Per capita data. Environmental agencies have used per capita fish consumption rates to 

establish regulatory requirements. For example, several states have adopted surface water 

quality standards that are based on the 90th percentile of 17.5 g/day.

 Consumer-only data. Environmental agencies have used consumer-only fish consumption 

rates to establish regulatory requirements. For example, the EPA Region 10 framework 

includes several default fish consumption rates that are based on consumer-only 

information. 
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6.7 Other exposure variables

Ecology uses a risk assessment approach to establish cleanup standards and water quality 

standards based on human health protection. Risk-based concentrations can be calculated for 

both cancer and non-cancer health effects using standard risk assessment equations. This 

document is not designed to provide a detailed discussion on individual exposure parameters and 

the relationships between those parameters and the fish consumption rate used to calculate riskbased concentrations. However, when selecting fish consumption rates used in regulatory 

decisions, it is important to consider the following points: 

 Regulatory choices on individual parameters need to be based on a common exposure 

scenario. It is important that agencies select fish consumption rates that are consistent 

with other exposure parameters. For example, if risk calculations are performed using a 

child’s body weight, the fish consumption rate should be based on the amount of finfish 

and shellfish eaten by children. 

 Regulatory choices on individual exposure parameters need to recognize the value 

judgments embedded in those parameters and the cumulative impact of those choices. For 

example, selecting upper percentile values for all exposure parameters will result in a risk 

estimate that does not represent a “reasonable” maximum exposure scenario (RME).

 Values should be concordant with the populations chosen to represent regulatory 

exposure scenarios, for example body weight for tribal populations or particular ethnic 

groups. Similarly, exposure duration should reflect the duration of times populations 

selected for evaluation use water bodies for fishing. Tribes have Usual and Accustomed 

fishing areas they may use over long periods of time. Individuals may relocate over 

limited geographic areas and still utilize water bodies for fishing with the implication that 

times in a single residence may not be an appropriate exposure duration.

 How bioaccumulation is accounted for is also a source of uncertainty and variability. The 

use of bioconcentration factors (BCFs) that relate contaminant concentrations in aquatic 

biota to those in water are being replaced by bioaccumulation factors (BAFs) that relate 

contaminant concentrations in aquatic biota to those from all sources. 

 Figures 15 and 16 illustrate other exposure parameters. Shown are equations used to 

establish MTCA surface water cleanup standards based on non-cancer hazard and cancer 

risks (Figures 15 and 16, respectively). In addition to a default fish consumption rate, the 

equation includes default values for body weight, exposure duration, and fish diet 

fraction. A similar (but not identical) equation is used to establish water quality 

standards. Several of the exposure assumptions used to establish water quality standards 

are different than those used under the MTCA rule. 
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CUL =

 

 

Where: 

CUL = Surface water cleanup standard (μg/L)

RfD = Reference Dose as specified in WAC 173-340-708(7)

ABW = Average body weight During the exposure duration (70 kg)

UCF1 = Unit conversion factor (1000 μg/mg)

UCF2 = Unit conversion factor (1000 g/liter)

BCF = Bioconcentration factor as defined in WAC 173-340-708(9) (liters/kilogram)

FCF = Fish consumption rate (54 g/day)

FDF = Fish diet fraction (0.5, unitless)

HQ = Hazard quotient (1 unitless)

AT = Averaging times (30 years)

ED = Exposure duration (30 years)

Figure 15. MTCA Surface Water Cleanup Standards Equation (Non-Carcinogenic 

Hazards)

Figure 16. MTCA Surface Water Cleanup Standards Equation (Carcinogenic Risk)

( * * * * )

( * * * 1* 2)

CPF BCF FCR FDF ED

RISK ABW AT UCF UCF CUL 

Where:

CUL = Surface water cleanup standard (μg/L)

RISK = Acceptable cancer risk level (1 in 1,000,000) (unitless)

ABW = Average body weight during the exposure duration (70 kg)

AT = Averaging time (75 years)

UCF1 = Unit conversion factor (1,000 μg/mg)

UCF2 = Unit conversion factor (1,000 grams/liter)

CPF = Carcinogenic Potency Factor as specified in WAC 173-340-708(8) (kg-day/mg)

BCF = Bioconcentration factor as defined in WAC 173-340-708(9) (liters/kilogram)

FCR = Fish consumption rate (54 grams/day)

FDF = Fish diet fraction (0.5) (unitless)

ED = Exposure duration (30 years)
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6.8 Acceptable risk levels

Washington’s current Water Quality Standards and MTCA Cleanup Regulation are both based 

on an acceptable cancer risk of 1 in 1 million and a hazard quotient of one. These are central 

policy choices that will continue to be discussed and debated. By necessity, decisions on 

acceptable risk levels are informed by science but require consideration of a wide range of other 

factors. For example:

 Statutory requirements.

 Social preferences on risk avoidance and distinctions between voluntary and involuntary 

risks.

 Uncertainties associated with risk assessment methods.

 Risk tradeoffs, including the health benefits associated with eating finfish and shellfish.

 Risk comparisons, including the risks associated with other common activities. 

 Economic impacts of attaining target risk levels.

This technical support document focuses on information about fish consumption. It does not 

provide a detailed discussion on risk policy. Ecology acknowledges that when selecting fish 

consumption rates for use in regulatory decisions it will be important to consider the 

relationships and interactions between the various policy choices. 

6.9 Summary

Agencies must address many scientific and policy issues when selecting a fish consumption rate 

for use in particular regulatory situations. Chapters 3 through 5 compile the currently available 

information on fish consumption rates in Washington. This chapter describes eight policy 

choices that should be addressed when using this information in a regulatory context. These 

policy choices must take into account statutory mandates and values that inevitably reflect 

explicit or implicit choices on how to deal with scientific uncertainty and variability. There are 

often multiple answers to these questions surrounding these issues. This chapter provides 

examples of how Ecology or other agencies have resolved those issues in the past.
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Appendices

Appendix A Information on 

Bioaccumulation, Fish Consumption by 

Children, and Species Consumed

This appendix includes information on:

1. Bioaccumulation

2. Children’s fish consumption rates

3. Data on species consumed

This information is included in this document to provide additional context for considering fish 

consumption rates. For additional information readers are referred to references cited. 

A.1 Bioaccumulation

Bioaccumulation of contaminants in finfish/shellfish 

A detailed discussion regarding the bioaccumulation of chemicals in aquatic biota is beyond the 

scope of this appendix. The EPA’s Methodology for Deriving Ambient Water Quality Criteria 

for the Protection of Human Health (2000) dedicates an entire chapter on the subject of 

bioaccumulation and changes in methodologies since the 1980s to assess and predict the 

bioaccumulation of chemicals in aquatic biota. Federal and state guidance documents are 

available that provide detailed analysis to assess and predict the bioaccumulation of chemicals in 

aquatic biota (U.S. EPA, 2000b, 2000c, 2007a; State Water Resources Control Board of

California, 2004; CalEPA, 2006). An 800-page appendix to EPA’s Bioaccumulation Testing and 

Interpretation for the Purpose of Sediment Quality Assessment provides chemical-specific 

information relevant to the bioaccumulation of chemicals in aquatic biota (U.S. EPA, 2000c, 

Appendices).

EPA makes a clear distinction between the terms bioaccumulation and bioconcentration. The 

term bioaccumulation “refers to the uptake and retention of a chemical by an aquatic organism 

from all surrounding media (e.g., water, food, sediment).” The term bioconcentration “refers to 

the uptake and retention of a chemical by an aquatic organism from water only” (U.S. EPA, 

2000b). The 2000 EPA guidance reflects the use of bioaccumulation factors (BAFs) to reflect the 

uptake of a contaminant by fish from all sources rather than just from the water column reflected 

by the use of bioconcentration factors (BCFs). For chemicals that are persistent and hydrophobic, 

the magnitude of bioaccumulation by aquatic organisms may be substantially greater than the 
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magnitude of bioconcentration. The 2000 EPA Ambient Water Quality Methodology provides 

important concepts regarding the bioaccumulation process as follows (U.S. EPA, 2000b, p. 5–2):

Another noteworthy aspect of bioaccumulation process is the issue of steady-state 

conditions. Specifically, both bioaccumulation and bioconcentration can be viewed as the 

results of competing rates of chemical uptake and depuration (chemical loss) by an 

aquatic organism. The rates of chemical uptake and depuration can be affected by 

various factors including the properties of the chemical, the physiology of the organism 

in question, water quality and conditions, ecological characteristics of the water body 

(e.g., food web structure), and the concentration and loadings history of the chemicals. 

When the rates of chemical uptake and depuration are equal, tissue concentrations 

remain constant over time and the distribution of the chemical between the organism and 

its sources(s) is said to be at steady-state. For constant chemical exposures and other 

conditions, the steady-state concentration in the organism represents the highest 

accumulation potential of the chemical in that organism under those conditions. The time 

required for a chemical to achieve steady state has been shown to vary according to the 

properties of the chemical and other factors.

The EPA further notes that...“criteria for the protection of human health are typically designed 

to protect humans from harmful lifetime or long-term exposures to waterborne contaminants, the 

assessment of bioaccumulation that equals or approximates steady-state accumulation is one of 

the principles underlying the derivation of national BAFs. For some chemicals that require 

relatively long periods of time to reach steady-state in tissue of aquatic organisms, changes in 

water column concentrations may occur on a much more rapid time scale compared to the 

corresponding changes in tissue concentrations. Thus, if the system departs substantially from 

steady-state conditions and water concentrations are not averaged over a sufficient time period, 

the ratio of the tissue concentration to a water concentration may have little resemblance to the 

steady-state ratio and have little predictive value of long-term bioaccumulation potential” (U.S. 

EPA, 2000b).

There are several important factors that may affect a chemical’s bioavailability and influence its 

bioaccumulation in fish. These factors include a wide range of physical, chemical, and biological 

characteristics associated with the contaminants, sediments, and aquatic biota (U.S. EPA, 

2000c).

Chemical bioavailability. Chemical bioavailability is a complex interplay between the physicalchemical properties of the contaminant as well as the behavior and physiology of the aquatic 

biota.

Physical factors of sediments affecting bioavailability and bioaccumulation. Sediments are 

complex and dynamic environments with a wide range of interacting biological and chemical 

processes that influence a chemical’s bioavailability and bioaccumulation into fish tissues. 
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Variable rates of mixing surficial sediment layers by physical processes of turbulence and 

bioturbation compete with rates of sedimentation. In addition, resuspension of sediments may 

also impact the bioavailability of sediment-associated contaminants by exposing filter feeders to 

contaminated particulates or by increasing the aqueous concentration of a contaminant via 

desorption from the particulates within the water column.

Chemical factors affecting bioavailability and bioaccumulation. The physical-chemical 

characteristics of a contaminant (molecular size and polarity) may influence the degree of 

association with particles and affect the chemical’s bioavailability. Many persistent and 

bioaccumulative toxic chemicals (PBTs) are large, nonpolar compounds, with low water 

solubilities and a strong tendency to be associated with dissolved and particulate organic matter. 

Hydrophobic chemicals, those that are strongly lipophilic, are a critical factor in determining the 

bioaccumulation behavior of organic chemicals in aquatic systems.

Biological factors affecting bioavailability and bioaccumulation. EPA notes that 

bioaccumulation is a multi-factorial process that combines the chemical with the biological (U.S. 

EPA, 2000c, p. X):

Bioaccumulation is a function of the bioavailability of contaminants in combination with 

species-specific uptake and elimination processes. Toxicity is determined by the exposure 

of an animal to bioavailable contaminants in concert with the animal’s sensitivity to the 

contaminant. These processes have been shown to be a function of the organism’s lipid 

content, size, growth rate, gender, diet, and ability to metabolize or transform a given 

contaminant, as well as the chemical conditions of the surrounding medium. Other 

biological factors that can affect a contaminant’s bioavailability include the burrowing 

and feeding behavior of the individual organism or species. The depth to which an 

organism burrows, the type of feeding mechanism it uses (e.g., filter feeding, particle 

ingestion), the size range of sediment particles it consumes, and its diet all have a large 

influence on the concentration of contaminant to which the organism will be exposed.

A.2 Children’s fish consumption rates

The Child-Specific Exposure Factors Handbook and the Highlights of the Child-Specific 

Exposure Factors Handbook summarize children’s fish consumption rates for different age 

groups. The mean and 95th percentile consumer-only total fish (marine, estuarine, freshwater) 

consumption rate for 16 to less than18 years of age for the general population is 2.1 grams per 

kilogram per day (g/kg/day) (136 g/day) and 6.6 g/kg/day (357 g/day), respectively (U.S. EPA, 

2008, 2009b). The mean and 95th percentile consumer-only total fish (finfish and shellfish) 

consumption rate for 3 to under 6 years old for the general population is 4.2 g/kg/day (78 g/day) 
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and 10 g/kg/day (186 g/day), respectively (U.S. EPA, 2009b, Table 1).

46 The Interim Report 

Child-Specific Exposure Factors Handbook summarizes the fish consumption rates among Native 

American children (consumers only, 5 or 6 years old or younger) using Pacific Northwest fish 

consumption survey information (U.S. EPA, 2002a). 

Table A-1. Fish Consumption Rates of Native American Children 5 or 6 Years of 

Age or Less

Survey (Native Populations) Mean 

(g/day)

90th Percentile a

(unless otherwise noted, g/day)

95th Percentile 

(g/day)

CRITFC, 1994 (Umatilla, Yakama, Nez 

Perce, Warm Springs) 25 63 73

Toy et al., 1996 (Tulalip and Squaxin 

Island Tribes) b

11 21 (86th percentile)

Suquamish Tribal Survey, 2000 c 21 48 103

a. Values are the 90th percentile unless otherwise noted.

b. Consumption rate calculated using the average body weight of 15.2 kilograms reported in Toy et al., 1996.

c. Consumption rate calculated using the average body weight of 14.1 kilograms from the general population.

Although the age groups and body weights may differ across the general and Native American 

children population groups, the fish consumption rates for the children begin to approximate one 

another at the upper percentiles (78 to 186 g/day and 63 to 103 g/day). EPA has noted that there 

is a high degree of variability in fish consumption rates across the Pacific Northwest tribes (U.S. 

EPA, 2009a). The 2008 Oregon DEQ Human Health Focus Group Report referenced EPA’s Per 

Capita Fish Consumption in the U.S. (2002) as supporting documentation for the children’s fish 

consumption rate (consumers only) of 191 g/day (Oregon DEQ, 2008; U.S. EPA, 2002a, Section 

5.2.1.1, Table 4). The same documentation and children’s fish consumption rate (190 g/day) is 

used to recognize the variability expressed by different fish consumption rates for different fishconsuming populations.

The following tables summarize analysis of fish consumption rate data for surveys identified by 

Ecology as meeting measures of technical defensibility. These tables are included here to show 

age group data. 

 

46 This consumption rate uses a body weight of 18.6 kilograms for children 3 to <6 years of age.
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Table A-2. Tribal Fish Consumption Rates

Fish Consumption Rate by Age Group From Selected Pacific Northwest Tribes

Age Group Mean 50th Percentile 90th Percentile 95th Percentile

Columbia River Basin Tribes (g/day)

Adults 58.7

18–39 57.6

40–59 55.8

60 and over 74.4

Tulalip Tribes (g/kg/day)

0–5 0.2 0.08 0.7

18–34 0.06 2.0 2.6

35–49 1.0 3.7 4.2

50–64 0.5 1.6 1.6

65 and over 0.2 0.6 0.6

Adults 0.9 0.6 2.9

Squaxin Island Tribe (g/kg/day)

0–5 0.8 0.5 2.1

18–34 0.5 2.3 3.1

35–49 0.5 2.6 3.0

50–64 1.1 3.6 3.6

65 and over 0.8 2.2 2.2

Adults 0.9 0.5 3.0

Suquamish Tribe (g/kg/day)

0–6 1.5 3.4

Adult Males

16–42 3.3 2.3 8.6 13.0

43–54 5.2 4.6 10.3

55 and over 1.6 1.4 4.8

Adult Females

16–42 1.9 1.0 4.9 10.1

43–54 1.2 0.8

55 and over 3.7 2.1

Source: Adapted from Moya, 2004, Table 5, p. 1204.

Table A-3. Fish Consumption Rate Data for Asian and Pacific Islanders

Asian and Pacific

Islanders in King County, 

by Age Group (g/kg/day)

Mean 50th Percentile 90th Percentile 95th Percentile

All respondents 1.9 0.8 2.4 3.9

18–29 1.8 2.1 3.9

30–54 1.6 2.3 3.8

55 and over 2.1 3.2 5.2

Source: Adapted from Moya, 2004, Table 4, p. 1203.
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Table A-4. EPA Data on Children’s Finfish and Shellfish Consumption Rates for 

the U.S. General Population

Fish Population 

Description

Fish Consumption by Age Group (g/kg/day)

3 to < 6 years 6 to < 11 years 11 to < 16 years 16 to < 18 years

Total fish

Mean per capita 0.43 0.28 0.23 0.16

95th percentile per capita 3.0 1.9 1.5 1.3

Mean consumer only 4.2 3.2 2.2 2.1

95th percentile consumer 10 8.7 6.2 6.6

Marine fish

Mean per capita 0.31 0.20 0.15 0.10

95th percentile per capita 2.3 1.5 1.3 0.46

Mean consumer only 3.7 2.8 2.0 2.0

95th percentile consumer 9.3 8.0 5.2 6.5

Freshwater fish

Mean per capita 0.12 0.08 0.08 0.07

95th percentile per capita 0.71 0.35 0.48 0.29

Mean consumer only 2.3 1.8 1.3 1.4

95th percentile consumer 7.2 6.2 4.4 3.3

Source: Adapted from U.S. EPA, 2009b, Table 1, p. 20.

A.3 Data on fish species consumed

The EPA Region 10 framework for establishing site-specific fish consumption rates for use at 

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites 

provides the following information related to types of seafood consumed. 

For adult members of the Tulalip Tribes, a 95th percentile total consumption rate of 194 g/day is 

obtained after adjusting the total consumption rate of 243 g/day to include only finfish and 

shellfish harvested from Puget Sound (Table A-5). This is based on information from the EPA 

Region 10 framework (U.S. EPA, 2007b, as cited in Windward Environmental, 2007, 

Appendix B).

Table A-5. Seafood Consumed by Adult Members of the Tulalip Tribes

Seafood Category Examples Central Tendency 

Estimate (g/day)

95th Percentile

(g/day)

Percent of 

Fish Diet

Anadromous fish Salmon/steelhead 14.9 96.4 49.7

Pelagic fish Smelt, mackerel, cod, perch 1.3 8.1 4.2

Benthic/demersal fish Halibut, sole, rockfish, snappers 1.2 7.5 3.9

Shellfish Crabs, clams, mussels, bivalves 12.5 81.9 42.2

Total ingestion rate 30 194 100
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For adult members of the Suquamish Tribe, a 95th percentile total consumption rate of 766.8 

g/day is obtained after adjusting the total consumption rate of 796 g/day to include only finfish 

and shellfish harvested from Puget Sound (Table A-6). This is based on information from the

EPA Region 10 framework (U.S. EPA, 2007b, as cited in Windward Environmental, 2007).

Table A-6. Seafood Consumed by Adult Members of the Suquamish Tribe

Seafood Category Examples 95th Percentile

(g/day)

Percent of Fish 

Diet

Anadromous fish Salmon/steelhead 183.5 23.9

Pelagic fish Smelt, mackerel, cod, perch 56.0 7.3

Benthic/demersal fish Halibut, sole, rockfish, snappers 29.1 3.8

Shellfish Crabs, clams, mussels, bivalves 498.4 65

Total ingestion rate 766.8 100

Freshwater fish make up 8.3 percent of the API seafood consumption, based on information from 

the API fish consumption survey from King County, Washington, as cited in Windward 

Environmental, 2007 (Table A-7).

Table A-7. Seafood Consumed by Adult Asian-Pacific Islanders (API)

Seafood Category Central Tendency Estimate 

(g/day)

95th Percentile

(g/day)

Percent of

fish diet

Anadromous fish 0.56 5.5 9.6

Pelagic fish 0.5 4.9 8.6

Benthic/demersal fish 0.24 2.4 4.2

Shellfish 4.6 44.2 77.5

Total 5.9 57 99.9
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Appendix B

Additional Fish Consumption Studies

This appendix includes information on additional studies considered by Ecology:

1. Background information

2. Biometric studies of Japanese and Korean populations in Washington State

3. Additional studies evaluated:

a. Makah Tribe

b. Port Gamble S’Klallum Tribe

c. Muckleshoot Indian Tribes

d. Upper Columbia River Resources Survey – Confederated Tribes of the Colville 

Reservation

e. Spokane River Surveys of Selected Ethnic Populations

f. Swinomish Tribal Study: Bioaccumulative Toxics in Subsistence-Harvested

Shellfish – Contaminant Results and Risk Assessment

4. Additional technical publications by Pacific Northwest tribal staff

B.1 Background information

Ecology identified a number of studies that provide information meeting measures of technical 

defensibility and that are appropriate for consideration of statewide fish consumption rates. Other 

studies are useful in providing multiple lines of evidence with respect to fish consumption. That is, 

numerous other studies, designed for various purposes, provide additional information that may be 

of value for particular evaluations or considerations. Although these studies may not have been 

conducted to identify specifically fish consumption rates of the population of interest, they assist in 

providing a robust picture of the importance of finfish and shellfish to the people of Washington. 

The studies discussed in this appendix are comprehensive but not exhaustive. For example, from 

July 2003 through December 2011, The Lands Council as part of the Spokane River Toxics 

Outreach, completed approximately 5,300 surveys, distributed about 10,000 health advisories, 

and participated in public education outreach of nearly 16,000 individuals in the Spokane area. 

This public outreach is to educate and increase public awareness of the health risks of PCBs in 

the Spokane River fish and heavy metal contamination in the Spokane River sediments. These 

surveys have targeted Slavic (eastern European, Russian) and Hispanic populations because they 

frequently harvest and consume fish from the Spokane River. Spokane River fish advisories 

recommend only one fish meal per month of fish from the river’s middle section and avoid 
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eating any fish from the Spokane River’s upper stretches.47 As noted in Chapters 3 and 4 of this 

Technical Support Document, these water body-specific surveys provide important information 

to support health protective advisories for people who harvest and consume fish from specific 

water bodies. All water body-specific fish dietary surveys, usually some form of a creel survey, 

are not detailed in this Technical Support Document. For a more detailed review of all of the 

water body-specific surveys and fish advisory information, the reader is referred to the 

Washington Department of Health’s website on fish advisories.48 The fish consumption related 

information provided in this appendix is important and credible information used to evaluate and 

assess the potential health risks from eating contaminated fish (seafood). The additional fish 

dietary information provided in Table 33 and this appendix provide multiple lines of evidence, as 

a weight of evidence approach, that people in Washington State harvest and consume large 

amounts of fish. The estimates of fish consumption detailed in Chapter 4 are based on fish 

dietary information based on survey methodology that allows for the projection of fish 

consumption estimates over a long period of time with descriptive statistics for percentile 

estimates. This type of information is important to help support health protective decisions to 

clean up contaminated sediments.

B.2 Biometric studies of Japanese and Korean 

populations in Washington State

Several studies have been conducted in Washington State to evaluate the fish consumption of 

Japanese and Korean populations (Tsuchiya et al., 2008a, 2008b, 2009; Cleland et al., 2009). 

These studies were conducted as part of the Arsenic Mercury Intake Biometric Study in 

collaboration with the University of Washington’s Institute for Risk Analysis and Risk 

Communication and the Washington State Department of Health. The studies were designed to 

evaluate mercury exposure within the Japanese and Korean communities and arsenic exposures 

within the Korean community of Washington State. Japanese and Korean populations in 

Washington State consume fish at higher rates than the national average (Sechena et al., 1999). 

These high fish-consuming populations may be exposed to mercury and arsenic from the 

consumption of finfish and shellfish. 

The fish consumption survey was based on surveys previously conducted for several other 

Pacific Northwest fish-consuming populations (tribal surveys and Sechena et al., 1999). The 

food frequency questionnaire was a validated dietary tool used and developed by the Fred 

Hutchinson Cancer Research Center and was self administered by the participants of this study. 

As part of the fish dietary survey, participants were provided a pictorial fish booklet, printed in 

three languages, containing pictures with names of various fish species commonly consumed by 

 

47 Spokane River Toxics Outreach, web location: http://www.landscouncil.org/water/river_toxics.asp?template=false

48 Washington State Department of Health Fish Advisory Information: http://www.doh.wa.gov/CommunityandEnvironment/Food/Fish.aspx
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Japanese and Koreans and seafood commonly found in the Pacific Northwest. Interview 

questions included frequency of consumption and serving sizes (based on fish models of fish 

steaks, fillets, sushi pieces, and shellfish samples). Also, participants were asked if they 

consumed any other fish not listed in the fish booklet. Survey participants were weighed unless 

they were pregnant. Pregnant women were asked to report their pre-pregnancy body weights.

The survey instrument included a series of questions that allowed for a cross-check of participant 

response about fish consumption. Mercury fish tissue concentrations were determined from fish 

commonly consumed by Japanese and Korean communities in the Puget Sound area from local 

Asian grocery stores. Fish or fish portions were purchased from multiple locations over a 4-week 

period. Analysis was conducted on skinless edible portions consisting of steaks or fillets.

Results from the Japanese and Korean fish dietary survey are shown in Table B-1 with 

comparisons made between the mean combined finfish and shellfish consumption rates (in red) 

with the 95th percentile national consumption rates (in red).

Table B-1. Fish Consumption Rates for Japanese and Korean Washington 

Populations

Population Finfish Consumption (g/day) Shellfish Consumption (g/day)

Mean 50th 95th Mean 50th 95th

Japanese (n = 106) 60 43 159 14 9 59

Korean (n = 108) 59 42 147 23 13 84

Population Finfish and Shellfish Combined Consumption (g/day)

Mean 50th 75th 90th 95th 99th

Japanese (n = 106) 73 55 100 164 188 241

Korean (n = 108) 82 64 112 170 230 329

CSFII 14 ---- 19 47 72 121

NHANES ---- ---- 0 43 87 ----

Source: Adapted from Tsuchiya et al., 2008b, Table 1.

Both Japanese and Korean respondents from this survey consume almost the same amounts of 

finfish (mean fish consumption of 60 g/day for Japanese and 59 g/day for Koreans). Also, this 

similarity in fish consumption for Japanese and Koreans is reflected in the finfish consumption 

distribution with 95th percentiles being 159 g/day for Japanese and 147 g/day for Koreans. 

Differences in amounts of total fish consumption for these two fish-consuming populations is 

due to the Koreans consuming nearly 70 percent more shellfish on a daily basis (22.7 g/day/ 

person) compared to the Japanese (13.5 g/day/person). The mean total fish consumption for 

Japanese (73 g/day) and Koreans (82 g/day) is almost identical to the 95th percentile estimates 

from CSFII and NHANES national fish dietary data. Based on comparison with national data, 

the authors noted (Tsuchiya et al., 2008b):
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The Koreans and Japanese women consume fish in quantities that exceed the national 

average. Mean values for the average values for the Japanese and Korean cohorts are 

significantly higher (73 and 82 g/day, respectively). Values of significance within the 

NHANES and CSFII distributions are the 95th percentile values (87 and 72 g/d, 

respectively) because the remaining 5% represent many persons. The average 

consumption values for the Koreans and Japanese approach or exceed these 95th

percentile values, indicating that these 2 populations may be contained within the 

remaining 5th percentile of the NHANES and CSFII distributions. On the basis of the 

percentile values for the consumption distributions from CSFII and NHANES, the 2 

populations investigated by us have central estimate shifts in consumption, leading to 

distribution patterns displaced to the right and further down the abscissa. Specifically, all 

the percentile consumption rates representing the national fish consumer were below 

those determined for the Japanese and Koreans.

Mean fish consumption estimates for Japanese and Korean women respondents for each of the 

clinic visits are provided in the table below. Additional details regarding the finfish species 

consumed and differences in rates from one clinic visit to another are provided in the Technical 

Issue Paper, Health Benefits and Risks of Consuming Fish and Shellfish (Ecology, 2012).

B.3 Additional studies evaluated

Makah Tribe

The Makah Indian reservation is located on the northwestern tip of the Olympia Peninsula in 

Washington State. The Makah Tribal usual and accustomed areas for harvesting finfish and 

shellfish extends east to the Elwha River, south to a geographic point between Ozette and the 

Quileute reservation, and north to the Canadian international border and the Swiftsure Bank. The 

geographic position of the Makah Indian reservation provides access to diverse terrestrial, 

freshwater, and marine resources to support subsistence practices.

An examination of the Makah subsistence practices was conducted by the University of 

Washington, Department of Anthropology, between 1997 and 1999. Jennifer Sepez’s 2001 

dissertation documents and evaluates the subsistence hunting, fishing, and shellfishing practices 

of the Makah Indian Tribe. For the purposes of this research, subsistence was defined as “the 

local harvest of natural resources for local consumption” (Sepez, 2001, p. 9). A random 

ethnographic survey sample of 15 percent of reservation households provided information on the 

contemporary subsistence harvests, uses, and consumption of finfish, shellfish, land mammals, 

marine mammals, and birds. Results indicate that 99 percent of the reservation households 

participate in some type of subsistence activities. 71 percent of the households engaged in 

harvesting resources, while 94 percent received resources harvested by another household. This 

comprehensive examination of Makah Tribal subsistence practices included hunting for deer, 
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elk, and grouse, and fishing for salmon, halibut, rockfish, black cod, and other species (Table 

B-2). Low tides in Neah Bay or adjacent tide flats provide areas for tribal harvesting of clams, 

mussels, barnacles, chitons, urchins, and other shellfish. Seal hunting occurs in conjunction with 

net fishing and canoeing. Regarding the Makah Tribal subsistence practices, the thesis noted

(Sepez, 2001, p. 19):

There is no homogeneous or even typical subsistence profile of Makahs. However, there 

are identifiable patterns of resource use in the community, and an accumulated history of 

legal, political, and ecological circumstances that frame contemporary subsistence 

activities as a place-and time-specific manifestation of ongoing traditions.

Although land-based subsistence harvesting is important, the majority of resources come 

from the sea. One saying around town that captures this orientation is “when the tide is 

out, the table is set.”

Table B-2. Percent of Households Using Subsistence Resources during 1997–

1998

Percent of 

Reservation 

Households

Subsistence Resource

76–100% Halibut, salmon, clams, crab

51–75% Mussels, deer, elk, goosenecks [boots], seal (meat and/or oil), salmon eggs, barnacles

26–50% Steelhead, lingcod, olive shells, chitons [slippers], octopus, rockfish, smelt, black cod, herring 

eggs, grouse

1–25%

Urchins [sea eggs], lingcod eggs, local cow, petrale, trout, tuna, bear, scallop, oysters, 

sole/flatfish, sea cucumber, squid, sturgeon, true cod, shrimp, rabbits, abalone, duck, pigeon, 

skate, sea lion, small gastropods, wolf eel.

Source: Adapted from Sepez, 2001, Table 4, p. 126. 

The Makah tribal subsistence diet is composed mainly of finfish and shellfish. Shellfish 

contribute 14 percent and finfish contribute 58 percent of the Makah tribal subsistence diet. The 

percent contribution of fish to the Makah subsistence diet is approximately eight times more than 

the percent contribution of fish consumed by the average American diet. Halibut is consumed at 

home by 93 percent of the households. Historical information suggests a strong dietary reliance 

on halibut, which differentiated the Makah Indian Tribe from other Pacific Northwest tribes 

whose main fish subsistence resource was salmon. However, 88 percent of the Makah tribal

households consume salmon, which surpasses halibut consumption when measured as pounds 

consumed per household. Table B-3 and Figure B-1 below illustrate the harvest and consumption 

practices of the Makah Tribe for fish resources in pounds. Salmon and halibut contribute more to 

the subsistence Makah diet by weight than any other types of fish combined.
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Table B-3. Makah Indian Tribe Per Capita Harvest and Consumption of 

Subsistence Fish (pounds)

Fish Species Mean per capita harvest

(all households)

Mean per capita 

consumption

(all households)

Mean per capita 

consumption 

(consumers only)

Halibut 55.6 27.4 28.9

Salmon 49.3 40.1 44.9

Steelhead 3.1 3.8 8.6

Lingcod 2.5 2.9 6.9

Rockfish 2.5 3.3 8.9

Smelt 2.4 2.7 10.0

Black Cod 1.3 1.2 5.9

Trout 0.04 0.1 0.4

Sturgeon 1.0 0.8 28.0

Skates 0.1 NA NA

Source: Adapted from Sepez, 2001, Table 6, p. 140.

Source: Adapted from Sepez, 2001, Figure 3, p. 139.

Figure B-1.Percent of Makah Tribal Households Consuming Subsistence Fish

2%

3%

3%

9%

6%

12%

18%

25%

28%

34%

40%

43%

88%

93%

0% 20% 40% 60% 80% 100%

Wolf Eel

Sturgeon

True Cod

Tuna

Sole/Flatfish

Trout

Petrale

Black Cod

Smelt

Rockfish

Lingcod

Steelhead

Salmon

Halibut

Percent of Households
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The survey vehicle administered to the Makah tribal reservation households obtained subsistence 

fish harvest and consumption information based on household harvest and consumption 

practices. Ecology did not use this information because the metrics from the results of the survey 

of tribal households (percent of tribal household consuming fish) is different than the metrics 

(grams/day) used for risk-based decision making. Furthermore, since information was not 

available regarding the number of residents per household, and the residency of the same 

household may vary depending on the extended family relationship within the Makah Tribe, it is 

not possible to determine an individual’s grams/day fish consumption rate based on this thesis. 

However, this thesis provides a comprehensive documentation of the composition of subsistence 

Makah tribal diet and subsistence lifeways and practices.

Port Gamble S’Klallum Tribe

Ecology consulted with the Port Gamble S’Klallam Tribe to determine a tribal fish consumption 

rate to establish sediment cleanup standards protective of human health. The Port Gamble 

S’Klallam Tribal fish consumption rates were based on the Suquamish Tribe Fish Consumption 

Survey using the EPA Tribal Fish Consumption Framework. The daily tribal seafood 

consumption rate of 499 g/day was determined for selected shellfish only and did not include 

salmon or other finfish. Tribal consultations are continuing to provide additional information 

regarding the amounts and types of shellfish consumed. Based on Port Gamble S’Klallam Tribal 

consultations and the application of the EPA Tribal Fish Consumption Framework, the following 

shellfish species are consumed:

 Total shellfish consumption (no finfish) is 499 g/day:

Geoduck 96.8 g/day

Littleneck clams 255.9 g/day

Oysters 62.4 g/day

Dungeness crab 83.9 g/day assuming 25% hepatopancreas (20.9 g/day) and 

75% meat (62.9 g/day). 

Ecology did not use this information to derive a default fish consumption rate because Port 

Gamble S’Klallam Tribal consultations are continuing to establish an accurate tribal fish 

consumption rate (Ecology, 2011a). 

Muckleshoot Indian Tribes

The Muckleshoot Indian Tribe has not performed a tribal fish consumption survey.49 However, 

the Muckleshoot Indian Tribe requested that EPA Region 10 develop a tribal exposure scenario 

to assist in characterizing the range of seafood consumption risks for the Lower Duwamish 

Waterway. In consultation with the Muckleshoot and Suquamish Indian Tribes, EPA Region 10 

 

49 Public Health Assessments and Health Consultations. ATSDR. http://www.atsdr.cdc.gov/hac/pha/pha.asp?docid=1312&pg=2#path
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and Ecology used EPA guidance to develop a tribal exposure scenario and derive fish 

consumption rates based on the Suquamish and Tulalip seafood consumption data. Using the 

EPA Region 10 guidance framework tribal exposure scenarios were developed for the Lower 

Duwamish Waterway for tribal adults consuming anadromous and pelagic finfish, 

benthic/demersal finfish, and shellfish. The Lower Duwamish Waterway Remedial Investigation 

Report provides a range of tribal consumption rates specific for the risk management decisions 

for the Lower Duwamish Waterway (Windward Environmental, 2007). The Lower Duwamish 

Waterway fish consumption rates are not applicable for Washington State high fish-consuming 

populations. Hence, the Lower Duwamish Waterway fish consumption rates were not used to 

derive a default MTCA fish consumption rate to establish surface water cleanup standards.

Upper Columbia River Resources Survey–Confederated Tribes of the 

Colville Reservation

Background information

The Confederated Tribes of the Colville Reservation and the EPA, Region 10 and Headquarters, 

collaborated on the Upper Columbia River Resources Survey (Confederated Tribes of the Colville 

Reservation and U.S. EPA, 2012). The upper Columbia River and Lake Roosevelt areas have 

been affected by contaminants from Teck Cominco lead-zinc smelter operations for over 100 

years. Residents of the Colville Reservation, located 50 miles downstream from Teck Cominco 

mine, may have been exposed to these contaminants and have collaborated with the EPA to assess 

and measure exposure pathways from the consumption of natural resources (including fish) that 

may be contaminated from the Teck Cominco operations. This information will be used by the 

EPA to conduct a human health risk assessment for the Upper Columbia River and Colville 

reservation residents. The resource use survey was conducted to support efforts to evaluate and 

assess the human health risks from exposures to contaminants from the Teck Cominco lead-zinc 

smelter located just north of the U.S. Canadian border.

Survey methodology

The Upper Columbia River Resources Survey is composed of two survey vehicles designed to 

investigate the food consumed and non-food uses harvested from local resources by residents of 

the Colville Reservation located in eastern Washington State. The Food Questionnaire was

administered by trained personnel to Colville Reservation residents regarding the consumption 

over the preceding 12-month period of several types of food groups: fish, birds, wild animals, 

farm animals, dairy products, fruits, vegetables, and wild plants. The Food Questionnaire survey 

method was a 24-hour dietary recall and included a previous 12-month food frequency recall and 

non-food use recall associated with resident uses of the reservation’s natural resources. Out of a 

pool of 5,893 people, 1,139 people over the age of 2 responded to the Food Questionnaire—

approximately 20 percent of the total resident population. A demographic weighting was applied 

to each respondent to account for the variance in response rate for residence location and age. 

The percentages and numbers of consumers provided in the Food Questionnaire data report will 
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vary from the percentage of individual respondents because of this demographic weighting of 

each respondent. The demographic weighting allows the calculation of numbers and percentages 

of Colville Reservation residents over the age of 2 years that consume selected types of foods. 

Results

Selected results of the Food Questionnaire related to fish consumption from Upper Columbia 

River Tribal Exposure Survey are presented in Table B-4.

Table B-4. Summary of Fish Type Consumed, Percentage of Population that 

Consumed Fish Type, and Percentage Harvest Source from Local 

Areas by Colville Reservation Residents

Fish Type

Percentage of 

Residents Consuming 

Fish Type

Frequency of 

Consumption 

(times/year)

Percentage 

Consumers Harvest 

from Local Areas

Salmon 73 15 74

Trout 46 13 92

Walleye 13 9 91

Smallmouth Bass 11 21 93

Crawfish 9 13 85

Mussels 8 9 12

Largemouth Bass 7 22 85

Panfish 6 25 79

Burbot 4 9 30

Sturgeon 3 40 68

Lake Whitefish 2 9 91

Mountain Whitefish 1 8 69

Lamprey 1 12 13

Aquatic Animals 1 18 100

Northern Pikeminnow 1 7 87

Other fish/aquatic animal <1 6 100

Sucker a <1 head/skin/organ/eggs 0%

Source: Adapted from Confederated Tribes of the Colville Reservation and U.S. EPA, 2012, Table 3.

a. Sucker was the only fish for which the head/skin/organ/eggs were reported to be consumed more frequently than the meat of the fish. 

However, a very low number of respondents reported eating suckers and all respondents were unsure of the harvest source of suckers 

consumed.

The 24-hour dietary recall survey provides information on food (fish) portion sizes while the 

previous year recall provides information on frequency of consumption for specific types of food 

consumed from local resources. Information about specific consumption rates is not yet 

available. However, important observations can be made from the above table. About 83 percent 

of the Colville Reservation residents ate fish in the previous year the survey was administered. 

The average number of local fish species consumed was 3 species with a maximum number of 

13 species consumed by residents. 73 percent of Colville Reservation residents ate salmon on an 

average of 15 times per year. Also, almost 20 percent ate the head, skin, organs, or eggs of 
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salmon. 61 percent of the respondents noted that all of their salmon was harvested from on or 

near the Colville Reservation and another 12 percent harvested part of their salmon catch locally. 

Freshwater mussels and crawfish are also harvested and consumed by Colville Reservation 

residents. 8 percent of the Colville Reservation residents ate mussels sometime during the previous 

year of the administered survey and 9 percent ate crawfish. 13 percent of the mussels were 

harvested all or partly locally. 81 percent of the crawfish were harvested entirely from local areas.

Many Colville Reservation respondents noted that they do not eat as much local fish as they 

would prefer because of concerns about smelter contaminants. Suppression of resources and 

reduced fish consumption remains an important concern by tribal populations. Tribal fish 

consumption and corresponding rates are artificially reduced due to concerns about contaminants 

and their associated effects.

Spokane River Surveys of Selected Ethnic Populations

Numerous and different types of surveys have been conducted for the Spokane River by the 

collaborative efforts of Spokane Regional Health District, Assessment/Epidemiology Center, 

Washington State’s Department of Health, and the Lands Council – Center for Justice. From July 

2003 through December 2011, The Lands Council – Center for Justice as part of the Spokane 

River Toxics Outreach, completed approximately 5,300 surveys, distributed about 10,000 health 

advisories, and participated in public education outreach of nearly 16, 000 individuals in the 

Spokane area.50 Surveys have focused on ethnic populations that may be exposed to legacy 

contaminants from mining operations (arsenic, lead, cadmium) and PCBs by harvesting and 

consuming fish from the Spokane River. Two types of surveys are briefly reviewed: (1) 1998 

Fish Consumption Survey, Spokane River, Washington (Spokane Regional Health District, 

1998), and (2) Lands Council – Center for Justice risk communication and public outreach 

survey (Robinson Research, 2007), which was directed to specific ethnic communities that 

harvest and consume fish from the Spokane River.

1998 Fish Consumption Survey, Spokane River

A 1998 Fish Consumption Survey was conducted by the Spokane Regional Health District, 

Assessment/Epidemiology Center to evaluate how people access the Spokane River for 

harvesting fish and to assess the fish consumption habits of Russian, Hmong, and Laotian 

populations. The objectives of the survey were to: (1) identify different types of fish caught from 

the Spokane River, (2) identify locations where fish are harvested, (3) identify populations who 

consume fish from the Spokane River, and (4) identify amounts of fish consumed and meal 

preparation methods. A mail survey questionnaire sampled two fish-consuming populations 

based on a random sample of Spokane County fishing license holders (2000 sample population)

 

50 Spokane River Toxics Outreach, web location: http://www.landscouncil.org/water/river_toxics.asp?template=false
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and individuals from a particular Spokane area fishing club (180 sample population from The 

Walleye Club). Russian and Laotian community representatives were hired by the Spokane 

Regional Health District to convene a focus group, serve as interpreters, translate the written 

survey, and coordinate the survey distribution within Russian and Laotian communities. Key 

findings for each of the two ethnic communities surveyed are provided below.

Key Russian Community Findings:

 Harvest locations: Upriver Dam, the old Walk in the Wild Zoo, River Front Park, 

downtown Spokane area, T.J Meenach Bridge, Nine Mile Bridge, and Long Lake.

 Fish harvested: rainbow trout, German (brown) trout, suckers, catfish, crayfish, pike 

minnow, smallmouth bass, and perch.

 Fish consumption: about 4 pounds per month (about 65 g/day or 2.3 ounces of fish per 

day).

Key Laotian Community Findings:

 Harvest locations: Nine Mile Bridge where the little Spokane and Spokane River meet.

 Fish harvested: catfish, rainbow trout, perch, bass, walleye, and crawdads.

 Fish consumption: two to three meals of Spokane River fish per month ( assuming a fish 

meal equals an 8-ounce serving, then two to three fish meals per month is about 16 to 24 

g/day or less than 1 ounce of fish per day).

2007 Spokane River Toxins Survey

Lands Council – Center for Justice conducted a telephone survey for adults living in Spokane, 

Lincoln, and Stevens Counties who live close to the Spokane River. The purpose of the survey 

was to evaluate public attitudes and perceptions regarding pollution in the Spokane River. A total 

of 600 telephone interviews were completed from December 2006 to January 2007 with 67

percent conducted in Spokane County, 17 percent in Lincoln County, and 17 percent in Stevens 

County. This telephone survey is part of a broader public outreach and education effort by the 

Lands Council directed to low-income families, indigenous people, and recent immigrant 

populations (Hmong, Vietnamese, Slavic, and Hispanic populations). Selection of these 

populations was based on previous work conducted by the Spokane Regional Health District, and 

State Departments of Health and Ecology, and suggests these ethnic populations may be at 

potential health risks from exposure to contaminants in fish harvested from the Spokane River.

There are a significant number of people catching and/or eating fish from the Spokane River. For 

those eating fish, few are taking precautionary measures in preparation of the fish. Results of the 

Lands Council – Center for Justice provides insights into public outreach and education 

challenges:
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 19 percent of respondents fish in the Spokane River.

 12 percent catch and eat fish. Over half eat two or more fish in months they are regularly 

fishing. 

 Of those who said they eat fish from the Spokane River in a typical year, nearly twothirds (65%) took no precautions in how they prepared the fish for cooking.

 The majority of fishing that includes eating what is caught takes place below Long Lake 

Dam (80%), where there are no fish advisories regarding consumption.

 Some fish consumption not in accordance with the Washington Department of Health 

fish advisory is occurring between Lake Spokane and the Idaho Border. 

The harvest locations from the Spokane River are as follows:

 80 percent below Long Lake Dam.

 10 percent from Spokane Falls to Long Lake Dam.

 4 percent from Upriver Dam to Spokane Falls.

 3 percent from the Idaho State Line to Upriver Dam.

 3 percent reported as Don’t Know/Refused.

The Laotian anglers were not evaluated for this survey since fewer than five surveys were 

returned from the 17 mailed surveys to the Laotian community. 

Sampling and analysis reports that evaluated for metals and PCBs in the Spokane River,

combined with findings from focus groups, established the questionnaire framework for the 

development of questions concerning fish harvest location and types of fish harvested. A mail 

survey questionnaire sampled two fish-consuming populations based on a random sample of 

Spokane County fishing license holders (2000 sample population) and individuals from a 

particular Spokane are fishing club (180 sample population from The Walleye Club). The mail 

survey questionnaire included an introductory letter asking participants to complete the survey if 

they harvest and consume fish from the Spokane River. A $50 gift certificate was included as an 

incentive to participate when the survey was completed and returned. There was about a 31

percent response rate to this mail survey.

Swinomish Tribal Study: Bioaccumulative Toxics in SubsistenceHarvested Shellfish – Contaminant Results and Risk Assessment

The Swinomish Indian tribal community is a federally recognized Indian tribe; the Swinomish 

Indian reservation is located on interior Puget Sound, Skagit County, Washington. The 

Swinomish Tribal Indian Community is a maritime fishing community with strong cultural and 

dietary dependence on fish and, particularly, shellfish. Shellfish are an abundant resource 
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harvested by the Swinomish Tribal Indian Community throughout their usual and accustomed 

fishing areas.51

The Swinomish Tribal Community Office of Planning and Community Development conducted 

a study to evaluate the toxicity and assess the risks from the consumption of contaminated clams, 

crabs, and fish (Swinomish Tribe, 2006). Chemicals of concern evaluated in this study include 

polychlorinated biphenyls (PCBs), arsenic, dioxins/furans, mercury, polycyclic aromatic 

hydrocarbons (PAHs), and selected chlorinated pesticides and metals. Focused sampling and 

analysis was conducted for sediments, clams, and crabs from North and South Skagit Bay, 

Padilla and Fidalgo Bays, and Crescent Harbor. 

An ethnographic-style survey (seafood diet interviews to evaluate current consumption pattern) 

was conducted for the Swinomish Tribal Community. Based on the ethnographic dietary survey, 

the Swinomish Tribal Indian Community documents 260 g/day (approximates an 8-ounce fish 

meal) for all seafood consumed harvested locally. The 260 g/day fish consumption rate was used 

for both adults and children to assess risks of individual clam and crab samples. Cumulative risks 

were based on a total of 300 g/day associated with the Swinomish Tribal Community 

consumption of 100 grams consumed daily each of clams, crab, and salmon. The risks from the 

consumption of contaminated seafood for the Swinomish Tribal Community are provided in 

Table B-5 below. The report notes “The ingestion rate of a total of 300 gpd [grams per day] is 

assumed for children as well as adults, which may overestimate intake for younger children. 

However, children are more sensitive to health effects, so assuming a higher per capita intake 

more accurately represents risks for younger children than simply scaling down the intake rate 

but not correcting for children’s increased sensitivity.” (Swinomish Tribe, 2006, p. 64)

The finfish/shellfish contaminants that contributed the most to human health risks were PCBs, 

arsenic, and dioxin/furans. Risks attributable from consuming 100 grams (3.5 ounces) of each 

species daily (total 300 g/day) are in the range of concern with non-cancer risk (HQ) for adults 

and children above 1 (ranging from 3 to 20), and lifetime cancer risks in the range of 1 in a 1,000. 

 

51 United States v. Washington, 459 F Supp. 1020, 1049 (W.D. Wash. 1979) “The usual and accustomed fish places of the Swinomish Tribal 

Community include the Skagit Rivers and its tributaries, the Samish River and its tributaries, and the marine areas of northern Puget Sound 

from the Fraser River south to and including Whidbey, Camano, Fidalgo, Guemes, Samish, Cypress, and the San Juan Islands, and including 

Bellingham Bay and Hale Passage adjacent to Lummi Island.”
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Table B-5. Cumulative Risks to Swinomish Tribal Finfish- and ShellfishConsuming Populations

Sampling Location and Seafood Type HQ Child

(6 Years)

HQ Adult

(70 Years)

Cancer Risk

(70 years lifetime)

Clams (Skagit Bay) 4 1 7E-04

Clams (Fidalgo and Padilla Bays) 5 1 9E-04

Crab (Skagit Bay) 3 0.7 8E-05

Crab (Fidalgo and Padilla Bays) 3 0.8 1E-04

Puget Sound Salmon 11 2 5E-04

Total Risk Ranges 17 to 21 3-5 1E-03 to 2E-03

Source: Adapted from Swinomish Tribe, 2006, Table 29.

Lummi Nation

The Lummi Indian nation conducted a survey to estimate seafood consumption for Lummi 

Indians living on the Lummi Indian Reservation and in surrounding areas of northwestern 

Washington State (Lummi Natural Resources Department 2012). The survey instrument used in 

the study was developed by the Lummi Natural Resources Department. The survey instrument 

used 54 species of seafood with questions on amount, seasonality, and frequency of consumption 

for each species. Separate information was obtained regarding seafood consumption at home 

and at tribal gatherings, demographic information, and information about fishing activity and 

patterns of consumption. The study evaluated historical fish dietary practices and rates in 1985 

because current rates for the tribe are suppressed (Lummi Natural Resources Department 2012):

The environmental baseline chosen for the Lummi Seafood Consumption Study was 1985, 

as this was the peak fish harvest year for the Lummi Nation in recent history and a goal 

of the Lummi Natural Resources Department is to restore fish habitat so that at least the 

1985 harvest levels can be sustained. As a result, the Tribal Advisory Committee 

determined that fish consumption rates from 1985 should be used to develop water 

quality standards and to support risk assessments of clean-up options for contaminated 

sites along Bellingham Bay. While not at Treaty-time levels, seafood abundance and 

availability was less of a limiting factor for seafood consumption during 1985 than in 

2012. Consequently, the seafood consumption rate would be less suppressed due to 

environmental degradation or the lack of available fish. A literature review showed that 

appropriate data could be elicited in recall studies that reach back 25 years.

The survey results are summarized below:

 Eighty-two (82) participants were interviewed over the May 2011 through March 2012 

survey period. 
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 Outliers were removed before the final calculation, which reduced the overall sample size 

used to compute the daily seafood consumption rate to 73 respondents. Outliers were 

defined by the Tribal Advisory Committee as respondents who reported consumption 

rates above the 90th percentile of the daily seafood consumption rate of all respondents. 

 The resultant average Lummi seafood consumption rate was calculated to be 4.73 grams 

per kilogram per day (g/kg/day) or approximately 383 grams per day (g/day) (0.84 

pounds per day [lb/day] or 13.5 ounces per day [oz/day]) for all seafood consumed.

 The median seafood consumption rate was calculated to be 3.82 g/kg/day or 

approximately 314 g/day (069 lb/day or 11 oz/day). 

 The 90th percentile seafood consumption rate was calculated to be 10.03 g/kg/day or 

approximately 800 g/day (1.76 lb/day or 28.2 oz/day). 

 The 95th percentile seafood consumption rate was calculated to be 11.28 g/kg/day or 

approximately 918 g/day (2.02 lb/day or 32.4 oz/day). 

 The final precision of the survey was ± 16.5%.

B.4 Additional technical publications by Pacific 

Northwest tribal staff

A Native American exposure scenario

This paper (Harris and Harper, 1997) documents a tribal-based subsistence exposure scenario for 

a variety of different foods and exposure parameters for use at the Hanford nuclear reservation 

cleanup. A subsistence fish consumption of 540 g/day is based on selected tribal interview from 

members of the Confederated Tribes of the Umatilla Indian Reservation and other published 

studies.

Lifestyles, diets, and Native American exposure factors related to 

possible lead exposures and toxicity

This article (Harris and Harper, 2001) documents that any assessment of the risk from lead 

exposure to tribal communities requires an understanding of the tribal community, resource base, 

and culture. Differences in patterns of exposure between different communities or groups of 

people are noted with documented additional sources of lead exposure for Native Americans.

A possible approach for setting a mercury risk-based action level 

based on tribal fish ingestion rates

Risks from the consumption of mercury-contaminated fish were evaluated with a recommended 

action level for mercury protective of Native American tribes in the Columbia River Basin at 0.1 

ppm or less (Harper and Harris, 2008). The recommendation is based on the combined risks from 
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mercury exposure plus other fish contaminants and exposures, the higher fish consumption rates 

associated with tribal populations, the existing cultural deficit due to loss of salmon, the health 

benefits from fish, and the cultural and economic importance of fish to tribal populations. To 

assess the risks from the consumption of mercury-contaminated fish, Harper and Harris (2008) 

defined the following fish consumption rates:

 Less than 100 g/day is the low tribal fish ingestion rate.

 100 to 454 (1 pound per day) g/day is the moderate tribal fish ingestion rate.

 Above 454 g/day is the true tribal subsistence rate.

Non-cancer and cancer risk to tribal populations from the consumption of mercury-contaminated 

fish was documented and within a risk range of concern.

Issues in evaluating fish consumption rates for Native American 

tribes

As a continuation and further refinement of the ethnographic survey conducted for the 

Swinomish Indian tribal community study, Bioaccumulative Toxics in Subsistence-Harvested 

Shellfish – Contaminant Results and Risk Assessment, Donatuto and Harper (2008) provide a 

Swinomish seafood dietary interview template as an alternative to conventional fish dietary 

surveys to estimate contemporary consumption. For traditional subsistence tribal fishers, a 

multidisciplinary method to reconstruct tribal heritage dietary practices and patterns is 

recommended. Donatuto and Harper identified several problems associated with conventional 

fish dietary surveys that are insensitive to cultural tribal practices and may lead to tribal 

misunderstanding about current fish dietary level and underestimate tribal consumption.
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Appendix C

The Question of Salmon

Salmon—showcase of the policy dilemma

The question of whether or how to include salmon in a fish consumption rate highlights the 

policy choices facing a regulatory agency. Multiple regulations—in this case MTCA and 

CWA—provide differing approaches to account for anadromous fish, with MTCA providing 

greater flexibility for site-specific modifications to regulatory standards.

Salmonids employ a complex life strategy. Most – but not all – adult salmon spend a portion of 

their lives outside of Washington waters. The inclusion of Pacific salmon in fish consumption 

rates is complicated by the question of where and to what extent salmon assume site-specific 

contaminants that contribute to their body burdens. 

Scientific knowledge related to the biology of the life history for the multiple salmon species has 

increased considerably with efforts to restore salmon in Puget Sound and throughout 

Washington. This once abundant resource has been reduced, and wild stocks of some species are 

endangered. Dams are being removed to restore once great salmon runs, and culvert work by 

necessity now involves salmon friendly design considerations. Effects of riparian zones, 

temperature, even predators like seals are studied. Understanding has increased of the differing 

strategies of fall and spring runs from Chinook, chum, coho, sockeye, and pink salmon, and 

whether they migrate through estuaries or directly from streams to the ocean. The recycling of 

contaminants means that when uptake occurs in the open ocean those chemicals are deposited by 

the dying salmon in their natal streams. In the face of this growing and sophisticated body of 

knowledge the classification of salmon as a marine species lacks subtlety and leads to regulatory 

dilemma. 

For example, Ecology’s Toxics Cleanup Program will consider several factors related to risk 

management when deciding how to address the question of salmon. Some of these factors are 

discussed in this appendix:

 The abundance of salmon.

 Salmon life cycles.

 Chemical contaminants in ambient waters and sediments.

 The unique quality of Puget Sound and other Washington waters.

Considerations of the complex life cycle and survival strategies of anadromous fish species like 

salmonids complicate and influence many risk management decisions. For example, risk 
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management cleanup decisions in Port Angeles Harbor and the Lower Duwamish Waterway are 

influenced by the presence/absences of salmonids in the harbor or waterway, migratory patterns, 

and contaminant body burdens attributable to site contaminants (Ecology, 2011b; Windward 

Environmental, 2007). The complication arises because it is difficult to attribute salmon 

contaminant body burdens to site-specific contaminants. 

This appendix describes the life cycle and survival strategies of salmonids. This information is 

related to policy and technical considerations regarding how to appropriately address the 

question of salmon when developing fish consumption rates for regulatory purposes.

C.1 Background

Salmon is consumed in abundance. On a global scale, over the last two decades, advances in

farmed-salmon production have tripled the world’s supply of salmon. In 1985, 6 percent of all 

salmon consumed around the world was farmed. In 1988, farmed salmon production surpassed 

wild fisheries. In 2000, 58 percent of all salmon consumed around the world was farmed, almost 

a tenfold increase from 1985 levels. In the United States, between 1987 and 1999, salmon 

consumption increased nine times (Institute for Health and the Environment). During that time 

period, salmon consumption increased annually at a rate of 14 percent in the European Union 

and 23 percent in the United States (Hites et al., 2004).

Over half the salmon sold globally is farm-raised in Northern Europe, Chile, Canada, and the 

United States. The annual global production of farmed salmon (Atlantic salmon, Salmo salar) 

has increased from approximately 24,000 to over 1 million metric tons during the past two 

decades (Institute for Health and the Environment; Charron, 2004, as cited in Hites et al., 2004). 

Contaminant body burdens in farm-raised salmon have been well documented and compared to 

wild salmon. European farm-raised salmon have significantly greater organochlorine (dioxin, 

dioxin-like PCBs, and selected pesticides) contaminant body burdens than those salmon raised in 

North and South America (Hites et al., 2004).

C.2 Factors influencing the health risk from 

consuming salmon

There are multiple factors to consider when assessing the risk from consuming salmon. Most 

Washington salmon spend the largest part of their lives in the open ocean, where exposure to 

contaminants originating from Washington sources is minimal. Salmon life cycles are complex, 

and the many species have different survival strategies. 

Ecology recognizes that salmon are an available Washington State resource for harvest and 

consumption. It is appropriate to consider:
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 Washington State estimates of recreational and commercial salmon harvests.

 Estimates of Washington State fish-consuming populations.

 Cultural and religious significance of salmon to different Native American fishconsuming populations in Washington State.

 The complexity of the salmon life cycle and survival strategies, local and global salmon 

contaminant body burdens, and Puget Sound resident and nonresident salmon 

populations.

 Federal and state regulatory policies and procedures.

Ecology notes that similarities between bioaccumulative and persistent contaminant 

(organochlorines) salmon body burdens from local and global distributions would preclude the 

ability to define a chemical fingerprint to attribute salmon body burdens to site-specific 

bioaccumulative and persistent contaminants

C.3 Information about salmon consumption in 

Washington

To determine how to appropriately address salmon when developing one or more default fish 

consumption rates, Ecology examined the regional fish dietary survey information regarding 

salmon-related consumption. These surveys show that salmon is consumed frequently and in 

large amounts. 

Based on Pacific Northwest regional-specific fish dietary surveys, salmon and selected types of 

shellfish are the most frequently consumed and consumed in the largest amounts of all seafood. 

Salmon is the most frequently consumed finfish (more than 90 percent) for all adult respondents 

from all of the regional-specific fish dietary surveys. (This observation follows the national trend 

where U.S. salmon consumption grew from 9.5 percent to 15 percent from 1996 to 2005 as a 

share [percentage] of finfish and shellfish consumption.52)

For the API populations surveyed, 96 percent of the survey respondents consume anadromous 

fish comprising greater than 10 percent of all seafood consumed (Sechena et al., 2003, Tables 2 

and 5). Also, 99 percent of the survey participants consume shellfish comprising more than 45

percent of all seafood consumed. The API survey participants consume a large variety of finfish 

and shellfish.

 

52 Fish and Shellfish Consumption data from National Marine Fisheries Service, Salmon Consumption data from National Fisheries Institute. 

Web location: http://www.fas.usda.gov/ffpd/Newsroom/Salmon.pdf, as cited in USDA, 2006.
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For the Tulalip Tribes and the Squaxin Island Tribe, 72 to 80 percent of anadromous fish 

consumed and 62 to 72 percent of shellfish consumed were harvested in the Puget Sound area

(Toy et al., 1996). When fish harvests are accounted for outside of the Puget Sound area, greater 

than 90 percent of the seafood harvested was anadromous. Of both the Tulalip Tribes and the 

Squaxin Island Tribe surveyed, greater than 90 percent of the survey respondents consume 

anadromous fish, which comprises almost 50 percent of all seafood consumed. The Tulalip 

dataset was adjusted for the harvest and consumption of finfish and shellfish from Puget Sound 

in the EPA Region 10 framework. With the adjusted rates used in the EPA Region 10 

framework, salmon and shellfish comprise about 50 percent each of the Tulalip tribal seafood 

diet, with salmon consumed in slightly greater amounts than shellfish. Hence, if the total fish 

ingestion rate did not account for salmon consumption, then the fish consumption rate would be 

reduced by about 50 percent, from 194 g/day to 97.6 g/day (U.S. EPA, 2007b, Appendix B-1,

Table B-1).

The Suquamish fish dietary survey identified the largest variety, most frequently consumed, and 

consumed in the largest amounts of finfish and shellfish for all of the Pacific Northwest tribal 

fish-consuming populations surveyed (The Suquamish Tribe, 2000). Fifty percent or more of the 

respondents consumed various types of anadromous fish and about 10 different types of 

shellfish. The Suquamish dataset was adjusted for the harvest and consumption of finfish and 

shellfish from Puget Sound in the EPA Region 10 framework. With the adjusted rates used in the 

EPA Region 10 framework, salmon and shellfish comprise about 25 percent and 65 percent, 

respectively, of the Suquamish tribal seafood diet. Hence, if the total fish ingestion rate did not 

account for salmon consumption, then the fish consumption rate would be reduced by about 25

percent, from 766.8 g/day to about 583 g/day (U.S. EPA, 2007b, Appendix B-2, Table B-2).

The fish dietary survey for the Columbia River tribal populations identified a variety of fish 

harvested and consumed in large amounts (CRITFC, 1994). However, this survey did not include 

any questions regarding shellfish consumption. Salmon is consumed by the largest number of 

adult respondents (92 percent), followed by trout (70 percent), lamprey (54 percent), and smelt 

(52 percent). Using the weighted mean fish consumption rate for adult fish consuming CRITFC 

tribal populations, salmon would contribute about 50 percent of the tribal seafood diet (≈25/63 

g/day). Hence, if the total fish ingestion rate did not account for salmon consumption, then the 

fish consumption rate would be reduced by more than about 50 percent, from a weighted mean 

of 63 to about 40 g/day.

C.4 Pacific salmon life cycle and survival strategies

Salmonids have complex life cycles and survival strategies, with large variations across and 

among different species (Quinn, 2005). The geographic distribution of Pacific salmonids extends 
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from San Francisco Bay northward along the Canadian and Alaskan coasts to rivers draining into 

the Arctic Ocean, and southward down the Asian coastal areas of Russia, Japan, and Korea.

53

Although variation exists, generally, Chinook, coho, and steelhead have migratory patterns along 

the Pacific continental shelf and remain in freshwater and estuarine environments for longer 

periods of time than other Pacific salmonid species. 

After pink, chum, and sockeye salmon enter the ocean environment, they rapidly migrate 

northward and westward through coastal waters of North America and are found in the open 

waters of the North Pacific, Gulf of Alaska, and the Bering Sea by the end of their first year at sea.

Table C-1. Pacific Salmon Life Cycle

Salmonid Life Cycle 

Environment

← Salmon Species →

Chinook Coho Sockeye Chum Pink Steelhead Cutthroat

Riverine rearing X X X X X

Estuarine rearing X X X X X

Lacustrine rearing X X

Nearshore migration X X X X X X X

Continental shelf 

migration X X X

Mid-oceanic migration X X X

Salmonid contaminant body burden

All seven Pacific salmon species are biotranporters of pollutants to and from the Pacific Ocean 

and their spawning sites in freshwater (Ewald et al., 1998). During river ascent, salmonids use 

their muscle lipid and triacyglycerol deposits for energy and gonadal development. Particularly 

in female salmonids, the organic pollutant body burden redistributes and accumulates in the 

lipid-rich gonads and salmon roe. Furthermore, the lipid depletions and redistribution during the 

river ascent are not coupled with a simultaneous elimination of the organic pollutant body burden 

in the salmonids. 

The pollutants in the salmonids are readily available for bioaccumulation, because the migrating 

salmonids, salmon roe, and salmon carcasses are a direct food source for predators (birds, 

mammals, and other fish). Hence, salmonids redistribute their pollutant body burdens back to 

their spawning grounds, to the open-ocean predators, or to the food web as bioaccumulation.

The redistribution, biotransportation, and bioaccumulation of the salmonid pollutant body burden 

helps contribute to food web contamination.

 

53 The definition and usage of terms freshwater, estuarine, and marine may vary according to context, with different writers using the terms 

differently. Readers should always verify how any terms are being defined.
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Persistent bioaccumulative toxics

Persistent bioaccumulative toxics (PBTs) are a group of chemicals that, because of their 

chemical and physical properties, exist within the environment for long periods of time, are 

lipophilic and bioaccumulate in fish tissue and animal fat, and are highly toxic to animals and 

humans (Puget Sound Action Team, 2007). The unique geologic and hydrogeologic nature of 

Puget Sound, in combination with the bioaccumulative, persistent, and toxic nature of the PBTtype contaminants, creates additional risks to the Puget Sound ecosystem. Some of the PBTs that 

continue to contaminate, threaten, or harm the Puget Sound ecosystem include PCBs, PAHs,

dioxins and furans; polybrominated diphenyl ethers (PBDEs), and hormone-disrupting chemicals 

(e.g., bisphenol A). PBTs are contaminants throughout the entire pelagic food web in Puget 

Sound (Puget Sound Action Team, 2007). 

Of the different PBTs that permeate the Puget Sound food web, PCBs are well-documented 

contaminants in coho and Chinook Pacific salmon (O’Neill et al., 1998). Pacific salmon 

exposure to PBTs, and PCBs in particular, is in part contingent on migratory patterns, residency 

time in Puget Sound, proximity of the salmon to contaminated sediments and waste sites, and 

different behavior and dietary patterns as the fish mature (Puget Sound Action Team, 2007; 

O’Neill et al., 1998). PCBs were detected in composite samples of adult Chinook and coho 

salmon collected from various in-river and marine locations in Puget Sound. Chinook salmon 

PCB tissue concentrations were greater than coho salmon PCB concentrations collected from inriver and marine locations. 

Table C-2. Average PCB Concentrations for Coho and Chinook Salmon from 

In-River and Marine Locations, Puget Sound (μg/kg)

Salmon Species Location Mean Concentration Marine In-River

Chinook 74.2 49.1 53.9

Coho 35.1 26.5 28.3

Mean 55.3 38.6 41.85

Source: Adapted from O’Neill et al., 1998. p. 316, Table 1.

The authors of a 1998 study investigating different factors and correlates associated with PCBs 

in muscle tissue of Chinook and coho salmon from marine and in-river locations in Puget Sound 

observed “...that Chinook salmon had significantly higher PCB concentrations than coho salmon 

and within each species, PCB concentrations were higher in fish caught in marine areas than inriver areas” (O’Neill et al., 1998, p. 323). Taking into account differences in their anadromous 

life cycles, age, and information from other studies evaluating contaminant exposures of salmon 

in the Puget Sound estuaries, this study suggested “...that Chinook and coho salmon accumulate 

most of their PCB body-burden in the marine waters of Puget Sound and the ocean, and because 
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Chinook salmon live longer and stay at sea longer than coho salmon they accumulate higher 

PCB concentrations in their muscle tissues” (O’Neill et al., 1998).54 The authors further noted 

that the salmon contaminant body burden attributable to freshwater and estuarine environments 

was negligible compared with residency time, growth patterns, and feeding habits of the salmon 

at sea. A 2005 study on the behavior and ecology of Pacific salmon and trout noted that salmon 

have high metabolic rates, feed heavily, and grow fast in the ocean (Quinn, 2005). 

Salmon can double their body length and increase their body weight tenfold during their first 

summer at sea. More than 98 percent of the final body weight of most salmon is attained at sea. 

For example, pink salmon entering the ocean may have a body weight of 0.2 gram but return 

from the sea weighing 2 kilograms, a ten thousand-fold increase. Further study also associates 

the percent contaminant body burden with fish biology (O’Neill et al., 2006). Coho and Chinook 

salmon populations that have more coastal migratory distributions have higher tissue 

concentrations of PCBs compared with those salmonids with more oceanic migratory 

distributions (chum, pink, and sockeye). Variations in the contaminant body burdens were noted 

and attributed to the marine distribution of the species (O’Neill et al., 2006, pp. 3–4):

...Chinook salmon returning to Puget Sound had significantly higher concentrations of 

PCBs and PBDEs compared to other Pacific coast salmon populations we sampled. 

Furthermore, Chinook salmon that resided in Puget Sound in the winter rather than 

migrate to the Pacific Ocean (“residents”) had the highest concentrations of POPs

[persistent organic pollutants], followed by Puget Sound fish populations believed to be 

more ocean-reared. Fall Chinook from Puget Sound have a more localized marine 

distribution in Puget Sound and the Georgia Basin than other populations of Chinook 

from the west coast of North American and are more contaminated with PCBs (2 to 6 

times) and PBDEs (5 to 17 times). 

Residence time in Puget Sound

Ecology evaluated a variety of information related to the residence time of salmon in Puget 

Sound and different river systems of Puget Sound. Several factors have a bearing on the salmon 

residence time:

 Biological variability exists across and within salmon species regarding migratory habits 

and behavior patterns.

 The location of rivers or streams within Puget Sound. Locations deep within the sound 

lengthen the time the salmon reside in the sound.

 

54 Chinook and coho salmon occupy three distinct habitat types during their life cycle: (a) Freshwater habitats (eggs hatch and fry develop); (b)

Puget Sound (smolts enter marine waters to feed and reside during migration); and (c) Ocean habitat.
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 Selected salmonid species do not die after spawning, and may spawn more than once,

migrating to and from the same river/stream in Puget Sound.

 With considerable species variability, selected salmonid populations do not migrate to the 

open ocean and, instead, remain in Puget Sound.

Different residency times of salmon within Puget Sound will result in more or less exposure to 

chemicals that contaminate the sound and, therefore, contribute to the contaminant body burden 

of salmon. Some salmon (resident “blackmouth” or Chinook salmon populations) may spend 

significant portions of their lives in Puget Sound. 

Salmon abundance

Interpreting salmon abundance records and historical records on salmon counts is complicated. 

Salmon are difficult to count because salmon populations are variable due to continual changes 

in freshwater and marine environments or to the cyclic nature of salmonid behaviors. Very long 

time-series records (a decade or longer) of catch or escapement are required for detecting large 

changes (50 percent or greater) in population abundance. Also, long-term changes in abundance 

may not occur as a continuous linear series of events and, therefore, are not accounted for with 

standard statistical evaluations. Therefore, records of abundance for short periods of time may 

suggest an increase or decrease in salmonid populations when, in fact, long-term trends are the 

reverse. The inherent biological variability of salmonids confers a level of uncertainty about the 

abundance counts and records associated with the different salmonid species (National Research 

Council, 1996, pp. 77–79).

Puget Sound salmon

The Puget Sound Basin includes the river systems in Puget Sound, Hood Canal, and the Strait of 

Juan de Fuca. As shown in the tables below (which provide the status of Washington and Puget 

Sound Salmon Stocks), there is a wide range of salmon population conditions in Puget Sound 

ranging from critical to healthy.55 Generally, for Puget Sound, the Washington Department of 

Fisheries (now referred to as the Washington Department of Fish and Wildlife) in 1993 classified 

about 44 percent of the salmon stocks as healthy, about 21 percent as depressed, about 5 percent

as critical, and about 30 percent unknown. Puget Sound is considered to have more depressed 

salmon stocks compared to the Washington coastal regions but fewer depressed stocks than the 

Columbia River Basin (National Research Council, 1996, pp. 86–90). Many wild salmon, 

steelhead, and bull trout stocks have been listed under the Endangered Species Act by the 

National Marine Fisheries Services or the U.S. Fish and Wildlife Service. As of 1998, less than 

50 percent of Washington’s salmon stocks were considered to be healthy (Governor’s Salmon 

 

55 Stock is defined by Governor’s Salmon Recovery Office (http://www.governor.wa.gov/gsr0/glossary/default.asp) as “fish spawning in a 

particular lake or stream(s) at a particular season which to a substantial degree do not interbreed with any group spawning in a different place 

at the same time, or in the same place at a different time.” The National Research Council (1996, pp. 12–13) notes that salmon stocks refers to 

a geographic aggregate of salmon populations that includes many local breeding populations of varied size and productivity.
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Recovery Office, 1999, pp. II.9 – II.10). The tables below summarize the status of salmon stocks 

for Puget Sound and Pacific Coastal areas and percentages associated with the different regional 

salmon stocks.

Table C-3. Status of Washington Salmon Stocks as of 1992

Status

Puget Sound Washington Coasts Columbia River All Of Washington

Number of 

Stocks %

Number of 

Stocks %

Number of 

Stocks %

Number of 

Stocks %

Healthy 93 44.7 65 56.5 29 26.1 187 43.1

Depressed 44 21.2 8 7.0 70 63.1 122 28.1

Critical 11 5.3 0 0 1 0.9 12 2.8

Unknown 60 28.8 42 36.5 11 9.9 113 26.0

Total 208 100 115 100 111 100 434 100

Source: Adapted from National Research Council, 1996, Table 4-4. Original data source is WDF et al., 1993.

Note: Status descriptors defined by the Washington Department of Fisheries (status criteria descriptors may change depending on regulatory 

agency or publication); as used by National Research Council, 1996:

Healthy: Stock of fish experiencing production levels consistent with its available habitat and within the natural variations in survival for the 

stock.

Depressed: Stock of fish whose production is below expected levels based on available habitat and natural variations in survival rates but 

above the level where permanent damage to the stock is likely.

Critical: A stock of fish experiencing production levels that are so low that permanent damage to the stock is likely or has already occurred.

Unknown: There is insufficient information to rate stock status.

Table C-4. Status of Puget Sound Salmon Stock as of 1992

Status Chinook Chum Coho Pink Sockeye Steelhead Total

Healthy 10 38 20 9 0 16 93

Depressed 8 1 16 2 3 14 44

Critical 4 2 1 2 1 1 11

Unknown 7 13 9 2 0 29 60

Source: Adapted from National Research Council, 1996, Table 4-3. Original data source is WDF et al., 1993.

The 1992 Salmonid Stock Inventory (SaSI) recognized 435 stocks of salmon and steelhead, one 

of which was extinct (WDF et al., 1993). When the 2002 data were published, WDFW made this 

information available online. Queries were available by Water Resource Inventory Area 

(WRIA), species, and stock. The 2002 update recognized an additional 54 stocks for a revised 

total of 489 salmon and steelhead stocks. However, the summary table for these stocks provided 

by WDFW on the SaSI 2002 update website only included 486 stocks. The 2002 status of these 

486 Washington State stocks is provided in Table C-5.
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Table C-5. 2002 By-Species Summary Update of WDFW’s Salmonid Stock 

Inventory (SaSI) Status for Washington State Salmon and Steelhead 

Stock Classifications.

Status Chinook 

(2002)

Chum 

(2002)

Coho 

(2002)

Pink 

(2002)

Sockeye 

(2002)

Steelhead 

(2002) Total

Healthy 35 41 47 6 4 33 166

Depressed 39 9 9 4 4 58 123

Critical 14 2 2 2 0 2 22

Extinct 1 8 0 0 0 0 9

Unknown 10 23 34 1 1 97 166

Total 99 83 92 13 9 190 486

Source: http://wdfw.wa.gov/conservation/fisheries/sasi/sasi_2002_introduction.html

When the geographic scale changes from Puget Sound to broader geographic areas of Pacific 

salmon habitat for the Northwest, the picture of abundance changes but still reflects declining 

populations. There is a drop in Pacific adult salmon returning to rivers to spawn. Historically, 56 

to 65 percent of the Pacific salmon returned to Alaska’s streams, 19 to 26 percent returned to 

streams in British Columbia, and 15 to 16 percent returned to streams in Oregon, Washington, 

Idaho, and California. Currently in the Pacific Northwest only 1 percent of Pacific salmon are

returning (Lichatowich, 1999, pp. 206–207).

WDFW hatchery release estimates to Puget Sound: 

WDFW provided Ecology with hatchery releases of yearling Chinook salmon into Puget Sound 

from 1993 to 2005. Chinook salmon released as yearlings tend to remain in the Sound for their 

entire life cycle. Although the Chinook salmon release estimates may be subject to revision, the

queried data by WDFW provide the most current estimates for Chinook salmon releases in the 

Puget Sound area and from the Dungeness and Elwha River hatcheries. Total hatchery releases 

of yearling Chinook salmon into Puget Sound (the Straits and North and South Puget Sound) 

ranged from a low of 1,835,320 in 2005 to a high of 3,367,106 in 1994 (WDFW, 2008b).

C.5 Chemical contaminants in Puget Sound

Chemical contamination of Puget Sound has occurred over a long period of time (150 years by 

some estimates) with various chemicals posing risks to the environment, aquatic life, and 

humans. 

Ecology noted at the March 2008 Science Advisory Board meeting, that PBTs pose a significant 

threat to the Puget Sound ecosystem. This section provides information about the presence, 

transport, and fate of chemical contaminants in and throughout Puget Sound. These chemicals 
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may be factors to consider when evaluating the chemical contaminant body burdens of salmon 

acquired on a site-specific basis.

Some of the chemical contaminants of concern for Puget Sound are:

Metals (Inorganic Contaminants) Organic Contaminants

 Lead

 Cadmium

 Tributyl tins

 Copper

 Mercury

 Arsenic

 Others

 Polychlorinated biphenyls (PCBs)

 Polycyclic aromatic hydrocarbons (PAHs)

 Dioxins and furans

 Selected pesticides

 Phthalate esters

 Polybrominated diphenyl ethers (PBDEs)

 Hormone disrupting chemicals (Bisphenol A)

 Petroleum and petroleum by-products

 Pharmaceuticals

Sources: Puget Sound Action Team, 2007, Table 4-1; West et al., 2011a, 2011b.

Polychlorinated biphenyls 

PCBs are persistent, bioaccumulative, and toxic chemicals found throughout Puget Sound. The bar 

chart below compares PCBs sampled in Chinook salmon fillets from Puget Sound and Chinook 

salmon fillets sampled for PCBs from other Pacific west coast areas. Puget Sound Chinook salmon 

fillets are almost three times more contaminated than fillets of Chinook salmon from other Pacific 

west coast areas (Puget Sound Action Team, 2007, adapted from Figure 4-18, p. 156).

PCBs

0 20 40 60

Kenai

Southeast Alaska

British Columbia

Puget Sound

Washington Coast

Columbia

Oregon

PCBs (ppb wet weight)
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The bar charts below illustrate differences in contaminant body burdens for salmon from Pacific 

West Coastal areas. The bar charts illustrate that Puget Sound resident Chinook salmon had the 

highest contaminant body burden of PCBs and PBDEs compared to other Pacific west coast 

areas. PCBs and PBDEs in whole body samples of individual summer/fall Chinook salmon from 

Puget Sound were 2 to 6 times more contaminated with PCBs and 5 to 17 times more 

contaminated with PBDEs than other populations of Chinook salmon from the Pacific west coast 

areas (Puget Sound Action Team, 2007, p. 157, Figure 4-19; O’Neill et al., 2006). 

PCBs in whole body Chinook

0

20

40

60

80

100

Northern

British

Columbia

Eastern

Vancouver

Island

Puget

Sound

Columbia

River

Central

California

PCBs (ppb wet weight)

Spring Run

Fall Run

Sub Adult Winter Resident
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C.6 Chemical contaminant transport in and around

Puget Sound

Puget Sound has unique geologic qualities among North American estuaries. These unique 

features confer a greater residence time for contaminants and trap them within the Sound, 

thereby increasing the potential for exposure.

The transport and fate of site-specific contaminants

Site-specific chemical contaminants in sediments may be relocated throughout Puget Sound by 

mechanical or biological transport mechanisms. Based on their life cycle, salmon play a unique 

role in the biological transport of contaminants in and through Puget Sound and contribute to the 

chemical contamination of the food web. 

Hydrodynamic conditions of Puget Sound

Puget Sound is unique among North American estuaries. Shallow sills at the northern and 

southern ends of central Puget Sound, where water is rapidly transported across the sills by tidal 

currents, influence circulation patterns. “The sills alter the normal pattern of estuarine circulation 

by causing mixing and by restricting the exchange of water with adjacent basins” (Ecology,

2007b).

PBDEs in whole body Chinook

0

10

20

30

40

50

Northern British Columbia

Eastern Vancouver Island

Puget Sound

Columbia River

Central California

PBDEs (ppb wet weight)

Spring Run

Fall Run

Sub-adult Winter Resident
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Contaminant residence times

The residence times for contaminants in Puget Sound are extended because the circulation 

conditions of the Sound, including the shallow sills associated with different inlets, 

freshwater/marine water gradients, and highly variable flow velocities in different areas of the 

Sound, all facilitate the trapping and mixing of toxic chemical contaminants. Chemical 

contaminants spend longer in the Sound increasing exposures to aquatic organisms, humans, and 

the environment.

Mechanical transport

Plastic debris may be transporting hydrophobic contaminants to sediments and sedimentdwelling (benthic infaunal communities) organisms (Teuten et al., 2007). Representative plastics 

(polyethylene, polypropylene, and polyvinyl chloride) were used to evaluate the preferential 

sorption of PAHs in plastics compared to sediments in marine environments. The addition of 

small amounts of PAH-contaminated plastics to sediments significantly increased the 

bioaccumulation of PAHs (phenanthrene) in sediment dwelling organisms. In addition, sorption 

of hydrophobic chemicals to plastics facilitates the transport of the contaminants to other areas in 

marine environments and to marine aquatic life. 

Contaminant dispersal, re-suspension, and transport

Chemical contaminants can be transported and dispersed throughout Puget Sound by a variety of 

processes. Chemical contaminants within different estuaries and marine water bodies can be 

transported and dispersed through different watersheds, bay and harbor areas, and inlets. The 

implications for the transport and dispersion of chemical contaminants throughout these water 

bodies is an increased potential for exposure to these contaminants by aquatic life and humans, 

regardless of where the contaminants originated from. 

Dispersal

Sediment reservoirs of historically discharged contaminants (metals, PAHs, PCBs, selected 

pesticides) may be disturbed and distributed by bioadvection, biodiffusion, and physical 

processes. The sediment-bound contaminants may be moved from the subsurface to upper 

sediments where the contaminants may undergo further resuspension and redistribution. Benthic 

infaunal communities (annelids, mollusks, crustaceans), storm events, and tidal influences 

contribute to the redistribution and dispersion of contaminated sediments (Niedoroda et al., 1996; 

Stull et al., 1996; Swift et al., 1996). 

Resuspension and transport

Historically deposited chemical contaminants buried in sediments may be resuspended in the 

water column and then transported and redeposited into coastal areas distant from the bay areas 

where the contaminants originated. Hydrodynamic processes include diffusion, tidal dispersion 

and transport of chemicals, sediment-water interactions, and adsorption-desorption of chemicals 
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to and from suspended particulate matter. Models evaluate the transport and fate of chemical 

contaminants from tidal estuaries and bay areas to other proximate marine environments. 

Empirical data support modeled outputs related to the remobilization of sediment contaminants, 

resuspension of the contaminants into the water column, and the subsequent redeposition of the 

contaminants to distant areas (Zeng and Venkatesan, 1999; Zeng et al., 2005). 

Biological transport

All seven Pacific salmon species are biotranporters of pollutants to and from the Pacific Ocean 

and their spawning sites in freshwater (Ewald, 1998). During river ascent, salmonids use their 

muscle lipid and triacyglycerol deposits for energy and gonadal development. Particularly in 

female salmonids, the organic pollutant body burden redistributes and accumulates in the lipid 

rich gonads and salmon roe. Furthermore, the lipid depletions and redistribution during the river 

ascent are not coupled with a simultaneous elimination of the organic pollutant body burden in 

the salmonids. The pollutants in the salmonids are readily available for bioaccumulation because 

the migrating salmonids, the salmon roe, and salmon carcasses are a direct food source for 

predators (birds, mammals, and other fish). Hence, salmonids redistribute their pollutant body 

burdens back to their spawning grounds, to the open-ocean predators, or bioaccumulate in the 

food web. The redistribution, biotransportation, and bioaccumulation of the salmonid pollutant 

body burden contribute to food web contamination.

Chemical contaminants are exhibited through the salmon life cycle, which contributes to the 

transport and distribution of contaminants in Puget Sound:

 Depletion of lipid reserves during upstream migration can cause significant biomagnifications 

of contaminant body burdens in eggs and gonadal tissues (Kelly et al., 2007).

 Post spawning decay of Chinook salmon carcasses are sources of persistent organic 

pollutants (POPs), such as PCBs, and dichlorodiphenyltrichloroethanes (DDTs), where 

body burden contaminants are released into river sediments and, furthermore, are 

released into the water column of tributary streams (O’Toole et al., 2006).

 Areas in the Pacific Northwest where Chinook salmon are harvested may account for the 

variations in their PCB body burden concentrations. Although some contamination of the 

Chinook salmon occurs in the Pacific Ocean, a larger source of the salmon body burden 

occurs within Puget Sound or along the migratory route within Puget Sound for Chinook 

salmon (Missildine et al., 2005).

 Chemical contaminants (selected pesticides and POPs) have been documented in 

outmigrant juvenile Chinook salmon (Johnson et al., 2007). 

Life histories and biological variability in life histories of Pacific coast salmonids

The following tables present detailed information on the life histories and biological variability 

of Pacific coast salmonids.
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Additional information on biological transport of contaminants is provided in the following 

publications:

 Data Report for Lower Columbia Juvenile Salmon Persistent Organic Pollutant Exposure 

Assessment. NOAA Damage Assessment Center, Portland Harbor Natural Resource 

Trustees,

 O’Toole, Shaun, Chris Metcalfe, Ian Craine, and Mart Gross. Release of persistent 

organic contaminants from carcasses of Lake Ontario Chinook salmon (Oncorhynchus 

tshawytscha). Environmental Pollution 140 (2006), 102-113.

 Missildine, Brian. Polychlorinated Biphenyl Concentrations in Adult Chinook Salmon

(Oncorhynchus tshawytscha) Returning to Coastal and Puget Sound Hatcheries. Master 

of Environmental Studies Thesis. The Evergreen State College. February 2005.

 Missildine, Brian, R., Roger J. Peters, Gerardo Chin-Leo, and Douglas Houck. 

Polychlorinated Biphenyl Concentrations in Adult Chinook Salmon (Oncorhynchus 

tshawytscha) Returning to Coastal and Puget Sound Hatcheries of Washington State. 

Environmental Science & Technology. 2005, 39, 6944-6951.

 Merna, James W., Contamination of Stream Fishes with Chlorinated Hydrocarbons from 

Eggs of Great Lakes Salmon. Transactions of the American Fisheries Society 115:60-74, 

1986.

 KrÜmmel, E. M., R. W. Macdonald, L.E. Kimpe, I Gregory-Eaves, et al. Delivery of 

pollutants by spawning salmon. Nature, Sept 18, 2003; 425; brief communications 255-

256.

 Kelly, Barry, C., Samantha L. Gray, Michael G. Ikonomou, J. Steve Macdonald, Stelvio 

M. Bandiera, and Eugene G. Hrycay. Lipid Reserve Dynamics and Magnification of 

Persistent Organic Pollutants in Spawning Sockeye Salmon (Oncorhynchus nerka) from 

the Fraser River, British Columbia. Environmental Science & Technology. 2007, 41, 

3083-3089.

 Johnson, Lyndal, L., Gina M. Ylitalo, Catherine A. Sloan, Bernadita F. Anulacion, Anna 

N. Kagley, Mary R. Arkoosh, Tricia A. Lundrigan, Kim Larson, Mark Siipola, Tracy K. 

Collier. Persistent organic pollutants in outmigrant juvenile Chinook salmon from the 

Lower Columbia Estuary, USA. Science of the Total Environment 374 (2007) 342-366.

 Janetski, David J., Dominic T. Chaloner, Ashley H. Moerke, Richard R. Rediske, James 

P. O’Keefe, and Gary A. Lamberti. Resident Fishes Display Elevated Organic Pollutants 

in Salmon Spawning Streams of the Great Lakes. Environmental Science & Technology. 

2012, 46, 8035-8043.
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 Hites, Ronald, A. Polybrominated Diphenyl Ethers in the Environment and in People: A 

Meta-Analysis of Concentrations. Critical Review. Environmental Science & 

Technology. 2004, Vol 38, No 4, 945-956.

 Gende, Scott, M., Richard T. Edwards, Mary F. Willson, and Mark S. Wipfli. Pacific 

Salmon in Aquatic and Terrestrial Ecosystems. Bioscience, October 2002, Vol. 52, No. 

10, 917-928.

 Fletcher, Demetrius. Concentrations of PCBs and PBDEs in water in the Cedar River and 

fish from the Lake Washington/Cedar/Sammamish Watershed. Master of Science, 

University of Washington. 2009.

 Report for 2001AK3481B: Final Report: Mercury Levels in Alaskan Rivers: Relationship 

between Hg levels and young salmon.

 Ewald, GÖran, Per Larrsson, Henric Linge, Lennart Okla, Nicole Szarzi. Biotransport of 

Organic Pollutants to an Inland Alaska Lake by Migrating Sockeye Salmon 

(Oocorhynchus nerka). Arctic, Vol 51, No. 1 (March 1998) pp. 40-47.

 Blais, Jules M., Robie W. Macdonald, Donald Mackay, Eva Webseter, Colin Harvey, and 

John P. Smol. Biologically Mediated Transport of Contaminants to Aquatic Systems. 

Critical Review. Environmental Science & Technology. 2007, Vol 41, No 4, 1075-1084.

 Blais, Jules M., Lynda E. Kimpe, Dominique McMahon, Bronwyn E. Keatley, Mark L. 

Mallory, Marianne S. V. Douglas, John P. Smol. Arctic Seabirds Transport MarineDerived Contaminants. Science, Brevia, July 15, 205, 309, 5733, pp 445.

 Macdonald, R., D. Mackay and B. Hickie. 2002. Peer Reviewed Contaminant 

Amplification in the Environment. Environmental Science & Technology, 36 (25), pp 

456A-462A.

 Marcy, S., D. Dasher, R. Deitz, L. Duffy, M. Evans, S. Juntto, S. Lindberg et al. Report 

for 2001AK3481B: Final Report: Mercury Levels in Alaskan Rivers: Relationship 

between Hg levels and young salmon.

 NOAA. 2009. Data Report for Lower Columbia Juvenile Salmon Persistent Organic 

Pollutant Exposure Assessment. Prepared by Environmental Conservation Division, 

Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic 

and Atmospheric Administration. Prepared for NOAA Damage Assessment Center and 

Portland Harbor Natural Resource Trustees. 
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Table C-6. Life Histories of Pacific Coast Salmonids

Species Spawning Migration Spawning Period Spawning Area Life History

Most 

Common Age 

at Maturity

(Years)

Anadromous Salmon

Chum salmon Summer to Winter Summer to Winter Usually near tidewater Fry go directly to sea; 2–5 years ocean 4

Pink salmon Late summer to early Fall Late summer to early Fall Usually near tidewater Fry go directly to sea; 2 years ocean 2

Sockeye salmon Spring to fall Late summer to fall Tributaries of lakes 1–3 years lake

2–3 years ocean 4–5

Coho salmon Summer to fall Fall to early winter Small headwater streams

1–3 years freshwater

6 months Jack ocean

18 month adult ocean

3

Chinook salmon Spring to fall Summer to early winter Large rivers 3 months to 2 years freshwater

2–5 years ocean 4–5

Anadromous Trout and Char

Steelhead trout Summer to winter Late winter to spring Small headwater streams

2–3 years freshwater

1–3 years ocean

Repeat spawners

4–5

Searun cutthroat trout Fall to winter Late winter to early spring Small headwater streams

2–4 years freshwater

2–5 months ocean

Repeat spawners

3–4

Dolly Varden a Late summer to fall Fall Main channels on rivers

2–4 years freshwater

2–4 years ocean

Repeat spawners

Mature 5–6

Die 6–7

Resident Species

Kokanee salmon Late summer to fall Late summer to fall Tributaries of lakes, 

lakeshores Juveniles migrate to lakes to reside 3–4

Rainbow trout Spring Spring Small headwater streams Variable residence in natal, streams, rivers, & lakes 2–3

Cutthroat trout Spring Spring to early summer Small headwater streams Variable residence in natal, streams, rivers, & lakes 3–4

Bull trout a Fall Fall Large streams with 

groundwater infiltration

Juveniles migrate from tributaries to lakes or large 

streams at about 2 years, highly variable 4–9

Mountain white fish Fall Fall Mid-sized streams, lakes Reside in streams and lakes 3–4

Source: Spence et al., 1996.

a. On occasion WDFW lumps bull trout and Dolly Varden together because both are listed under the Endangered Species Act and it is hard to differentiate the two species in the field; genetic studies 

have found bull trout throughout Puget Sound and the Strait (Duncan, 2008, personal communication).
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Table C-7. Biological Variability in Life Histories of Pacific Salmonids

Species of Salmon Life History Spawns In Rears In

Lakes Streams Intertidal Lakes Streams Estuaries Ocean

Pink salmon

Anadromous X X X X

Anadromous X X

Anadromous X X X

Chum salmon

Anadromous X X X X

Anadromous X X X

Anadromous X X

Anadromous X X X

Coho salmon Anadromous X X X X

Anadromous X X X

Sockeye salmon Anadromous X X X

Anadromous X X X

Chinook salmon (spring) Anadromous X X X X

Anadromous X X X

Chinook salmon (fall) Anadromous X X

Anadromous X X X

Steelhead Trout Anadromous X X X

Dolly Varden a Anadromous X X X X

Kokanee salmon Resident X X

Resident X X

Cutthroat trout Resident X X

Resident X X

Cutthroat trout (searun) Anadromous X X X X

Anadromous X X X

Rainbow trout

Resident X X

Resident X X

Resident X

Bull trout a

Resident X X

Resident X X

Mountain whitefish Resident X X

Resident X X

Source: Spence et al., 1996. 

a. On occasion WDFW lumps bull trout and Dolly Varden together because both are listed under the Endangered Species Act and it is hard to differentiate the two species in the field; genetic studies 

have found bull trout throughout Puget Sound and the Strait (Duncan, 2008, personal communication).
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Table C-8. 2001–2002 Freshwater Salmon Sport Catch for Puget Sound River 

Systems

Catch

Area Species 2001 2002 Total

April May June July August Sept Oct Nov Dec Jan Feb Mar

Dungeness 

River

Coho 5,949 597 12 6,558

Steelhead 9 43 22 107 58 9 4 252

Elwha River Coho 816 127 943

Steelhead 5 46 5 5 36 97

Morse Creek Steelhead 4 4

Total Salmon Sport Catch 7,854

Source: Adapted from Manning and Smith, 2005, Table 26, p. 42; Table 35, p. 92; and Table 35, p. 90.

Table C-9. 2001–2002 Sport Salmon Catch for East Juan de Fuca (Port Angeles 

Areas)

Species 2001 2002 Total

April May June July August Sept Oct Nov Feb Mar

Chinook 136 18 17 132 171 172 115 761

Coho 10 239 1,492 1,806 199 8 3,754

Pink 21 840 5,742 951 7,554

Sockeye 2 2

Chum 3 3 4 10

Steelhead 6 6 12

Total Salmon Sport Catch For Area 12,093

Source: Adapted from Manning and Smith, 2005, Table16, p. 25 and Table 35, p. 101. 

Table C-10. 2002–2003 Freshwater Salmon Sport Catch for Puget Sound River 

Systems

Catch

Area Species 2002 2003 Total April May June July August Sept Oct Nov Dec Jan Feb Mar

Dungeness 

River

Coho 398 711 25 1134

Steelhead 4 3 5 15 15 3 45

Elwha River Coho 948 175 1123

Steelhead 2 1 1 9 59 92 17 9 2 192

Morse Creek Steelhead 3 15 5 10 33

Total Salmon Sport Catch 2527

Source: Adapted from Kraig and Smith, 2008, Table 25, p. 41; Table 34, p. 87; and Table 34, p. 88.

Table C-11. 2002–2003 Sport Salmon Catch for East Juan de Fuca (Port Angeles 

Areas)

Species 2002 2003 Total

April May June July August Sept Oct Nov Feb Mar

Chinook 55 3 12 59 103 81 313

Coho 43 281 713 35 1072

Pink 21 21

Sockeye 0

Chum 12 12

Steelhead 3 3 3(Dec) 3(Jan) 12

Total Salmon Sport Catch For Area 1430

Source: Adapted from Kraig and Smith, 2008, Table 16, p. 25 and Table 34, p. 97.
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Table C-12. Salmonid Stock Inventory for the Port Angeles Harbor and Adjacent 

Areas

Anadromous Fish Total Escapement 

Estimates

WDFW Designated 

Status Comments

Species Stock From Year: 

Est. #

To Year: 

Est. # 1992 2002

Chinook

Dungeness 

Chinook 1986: 238 2003: 640 Critical Critical

Critical due to chronically low 

escapements below goal of 925 adults; 

increased escapement #’s due to 

continuing hatchery supplementation; 

spawning mainstream Dungeness River.

Elwha 

Chinook

1986: 

3,127

2003: 

1,045 Healthy Depressed

Depressed due to long-term negative 

trend and chronically low escapements 

since 1992; Spawning lower 4.9 mile of 

river below Elwha Dam.

Chum

Dungeness 

Summer 

Chum

1992: 

Unknown

2002: 

Unknown Not Rated Unknown

No abundance trend data available; 

Numbers so low that may not represent a 

self-sustaining stock; Summer timed 

limited #’s observed in Dungeness River.

Dungeness 

Fall Chum

1992: 

Unknown

2002: 

Unknown Unknown Unknown

Live + dead counts in one day, one mile 

section of (Lower Dungeness tributary) 

Beebe Creek 1997: 303, 1998: 1,025; 

2001: 1,062.

Elwha Fall 

Chum

1992: 

Unknown

2002: 

Unknown Unknown Unknown No abundance trend data available.

Source: WDFW, 2002. Salmon Stock Inventory. Water Resource Inventory Area (WRIA) 18 – Elwha-Dungeness.
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Table C-13. Salmonid Stock Inventory for The Port Angeles Harbor and Adjacent Areas

Anadromous Fish Total Escapement Estimates WDFW Designated Status Comments

Species Stock From Year: Est. # To Year: Est. # 1992 2002

Coho

Dungeness Coho 1992: 

Depressed

2002: 

Unknown Unknown Unknown

No abundance trend data available; Limited recent-year estimates 

of smolt production suggest significant natural production 

Dungeness R. watershed.

Morse Creek Coho

1998: 

488 adults and 

511 smolts

2002: 

676 adults and 

2, 966 smolts

Depressed Depressed

Spawning distribution: McDonald, Siebert, Morse, Ennis, Valley 

and Tumwater Creeks; Depressed because of chronically low 

“redd” counts; mixture of wild and farm-raised stock.

Elwha Coho Unknown Unknown Healthy Unknown No abundance trend data available; Healthy rating based on 

escapement estimates from Strait of Juan de Fuca tributaries.

Pink

Lower Dungeness 

Pink 1985: 966 2001: 11,072;2003: 3,540 Critical Critical

Estimates based on counts from mainstem of Dungeness R., Gold 

Creek, and Gray Wolf River; Critical designation due to chronically 

low escapements.

Upper Dungeness 

Pink

1985: 3,764

1989: 10,579

2001: 69,272

2003: 11,576 Depressed Depressed Prior to 1981 escapements usually in excess of 20,000; stock status depressed because of chronically low escapements.

Elwha Pink 1985: 30

1991: 0

2001: 605

2003: 32 Critical Critical

In early 1970s instantaneous counts over a thousand pinks were 

made; since 1981 not more than 30 pinks have been seen on any 

one day; stock status depressed because of chronically low 

escapements.

Table C-14. Salmonid Stock Inventory for the Port Angeles Harbor and Adjacent Areas

Anadromous Fish Total Escapement Estimates WDFW Designated Status Comments

Species Stock From Year: Est. # To Year: Est. # 1992 2002

Steelhead

Dungeness 

Summer Steelhead Unknown Unknown Depressed Unknown

No abundance trend data available. Due to fisheries closures and 

low harvest numbers sport harvest is no longer adequate to 

assess stock status.

Dungeness Winter 

Steelhead

1988: 438

1993: 338

2000: 165

2001 183 Depressed Depressed Depressed status because of long term negative trends.

Morse Creek Winter 

Steelhead 

1986: 105

1988: 138

1997: 183

2003: 84 Depressed Depressed Escapement estimates based on redd counts; depressed due to chronically low escapements.

Elwha Summer 

Steelhead Depressed Unknown Depressed Unknown No abundance trend data available.

Elwha Winter 

Steelhead

1986: 834

1989: 416

1992: 560

1997: 153 Depressed Unknown

Access to historic spawning areas blocked by Elwha Dam; 

Average of 50 redds/year; Lack of systematic abundance trend 

data.

Source: WDFW, 2002. Salmon Stock Inventory. Water Resource Inventory Area (WRIA) 18 – Elwha-Dungeness.
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Source: Adapted from Spence et al., 1996.
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Appendix D

Glossary

Anadromous fish: fish that hatch in freshwater, spend a portion of their life maturing in 

saltwater, then return to freshwater habitats to spawn.

Angler: one who fishes with hook and line, sometimes used to denote “fishers.”

Aquatic: from or living in a water body, including both marine and freshwater.

Bottomfish: fish that include Pacific cod, Pacific tomcod, Pacific hake, walleye Pollock, all 

species of dabs, sole and founders (except Pacific halibut), lingcod and all other species of 

greenling, ratfish, sablefish, cabezon, buffalo sculpin, great sculpin, red Irish lord, brown Irish 

lord, Pacific staghorn sculpin, wolf-eel, giant wry mouth, plainfin midshipman, spiny dogfish, 

six gill shark, soupfin shark and all other species of shark, and all species of skate, rockfish, 

rattails and surfperches except shiner perch.

Coastal waters: a term that refers to waters having a coastline that forms the boundary between 

land and freshwaters and marine and/or estuarine waters. This term encompasses all freshwaters 

of statewide significance (lakes, rivers, streams, etc.) and those marine and/or estuarine waters 

extending from the landward edge of a barrier beach or shoreline of coastal bay to the outer 

extent of the Continental Shelf.

Commercial fishers: those individuals who harvest finfish and/or shellfish by any method from 

Washington State waters (marine, estuarine, and freshwaters) for economic gain as a livelihood.

Creel survey: on-site interview with fishers to obtain information such as species caught; 

number, length, and weight of catch; location; etc.; typically for use by fisheries managers; may 

or may not include information on consumption.

Demersal fish: fish that dwell at or near the bottom of a body of water.

Estuarine: from an estuary, i.e., a partly enclosed water body, such as an inlet of the ocean or 

the mouth of a river where it meets the ocean that contains brackish water (a mixture of salty and 

freshwater) such as Elliott Bay in Seattle, Washington.

Finfish: fish; a term that is usually applied to the consumption of true fish as opposed to 

shellfish.
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Fish: any of various aquatic animals (belonging to the subphylum Vertebrata) having gills, 

commonly fins, and bodies usually but not always covered by scales, including those having 

bony skeletons (bony fishes) and more primitive forms with cartilaginous skeletons (lampreys; 

hagfishes; and sharks, skates, and rays).

Fish consumers: those individuals who consume finfish and/or shellfish; synonymous with 

Washington State fish-consuming populations.

Fisher: one who fishes for any type of seafood by any method, inclusive of hook and line and 

other methods of catching seafood.

Freshwater: water bodies including lakes, ponds, rivers, and streams that contain water with 

relatively low salinity, i.e., less that 0.5 parts per trillion; species inhabiting freshwater bodies.

Game fish: sport fish that are caught for food.

Indian (Native American) Reservation: land set aside by the federal government for the use, 

possession, and benefit of a Native American tribe or group of Indians; created by some formal 

legal directive such as a treaty, statute passed by Congress or an executive Presidential order.

Marine: from, or living in, the ocean; saltwater, with a salinity of approximately 35 parts per 

trillion.

Native American: a member of the indigenous peoples of the Western Hemisphere. In this 

technical support document the term “Indian” is used only with reference to the name of a 

specific Native American tribe. 

Noncommercial fisher: one who fishes for recreation and/or home consumption; synonymous 

with recreational fisher, sport fisher.

Pelagic fish: fish that live near the surface or in the water column of coastal, oceanic, and lake 

waters.

Reasonable maximum exposure (RME): 

The MTCA definition of RME (WAC 173-340-200) is as follows: 

Reasonable maximum exposure means the highest exposure that can be reasonably 

expected to occur for a human or other living organisms at a site under current and 

potential future site use. 
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The EPA definition of RME is as follows: 

Actions at Superfund sites should be based on an estimate of the reasonable maximum 

exposure (RME) expected to occur under both current and future land-use conditions. 

The reasonable maximum exposure is defined here as the highest exposure that is 

reasonably expected to occur at a site. RMEs are estimated for individual pathways (U.S. 

EPA, 1989b, page 6-4 to 6-5).

The worst-case exposure represents an extreme set of exposure conditions, usually not 

observed in an actual population, which is the maximum possible exposure where everything 

that can plausibly happen to maximize exposure happens (U.S. EPA Guidelines for Exposure 

Assessment, Federal Register Notice, Vol. 57, No. 104, May 1992, pages 22888-22938).

The preamble to the National Contingency Plan further indicates that the RME will:

...result in an overall exposure estimate that is conservative but within a realistic range 

of exposure. Under this policy, EPA defines “reasonable maximum” such that only 

potential exposures that are likely to occur will be included in the assessment of 

exposures. The Superfund program has always designed its remedies to be protective of 

all individuals and environmental receptors that may be exposed at a site; consequently, 

EPA believes it is important to include all reasonably expected exposures in its risk 

assessments...

Recall bias: Dietary recall surveys may cover specific periods of time or seasons; short term 

recall surveys may cover a 24-hour food recall to obtain information on the diet of an individual 

in the prior 24 hours. Dietary surveys that rely on an individual’s recall of their diet may undergo 

some recall errors that introduce an element of bias in the dietary estimates. These recall errors 

may result in either overestimation or underestimation of fish consumption. Factors that 

contribute to recall error and bias include how commonly or frequently the food (fish) is 

consumed, time frames covered by the survey that contribute to seasonal variation in food 

consumption, survey methods used including provisions to enhance dietary memory or recall 

(food models), and the desirability or cultural influences on the food consumed. Generally, recall 

error increases as the length of the recall period increases, with recall periods of 1 year likely to 

result in the least reliable estimates of consumption. The optimal recall period will be long 

enough to accurately portray typical dietary (fish consumption) habits and patterns without 

impairing the ability of respondents to recall their dietary (fish) consumption (Chu et al., 1992).

Recreational fisher: one who fishes primarily for recreational purposes; recreational catch is 

used primarily for home consumption; synonymous with noncommercial fisher, sport fisher.

Seafood: aquatic organisms that are consumed, including mainly finfish and shellfish, and less 

frequently, other invertebrate animals or plants or marine mammals.
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Shellfish: aquatic invertebrate animals having a shell or exoskeleton, the term usually used in 

the context of food, including species belonging to the following taxa (some of which have 

evolved such that the shell has become internal and/or reduced, or has disappeared entirely): (1)

mollusks, including bivalves (e.g., clams, oysters, mussels, scallops), gastropods (e.g., snails, 

limpets, abalone), and cephalopods (e.g., squid, octopods); (2) crustaceans (e.g., crabs, shrimps, 

lobsters); and (3) echinoderms (e.g., sea urchins, sea cucumbers).

Sport fish: fish that are caught by a sport fisher as opposed to purchased or caught 

commercially, synonymous with sport-caught, recreationally caught, and noncommercial fish.

Sport fishers: those individuals who harvest finfish and/or shellfish by any method from 

Washington State waters (marine, estuarine, and freshwaters) for recreation; synonymous with 

recreational fisher or noncommercial fisher.

Subsistence: Although no single universally accepted definition is available to define what is 

meant by subsistence or subsistence-based populations, several definitions of subsistence fishers 

may apply to Washington State ethnic groups and/or fish-consuming populations. It is difficult to 

define and to quantify subsistence fishers. Definitions and perceptions of what constitute 

subsistence fishers and fishing may vary among regions and cultures. The 1994 Presidential 

Executive Order 12898, Section 4-4. Subsistence Consumption of Fish and Wildlife noted 

differential patterns of subsistence consumption of fish and wildlife for populations who 

principally rely on fish and/or wildlife for subsistence.56 Differential patterns of subsistence 

consumption of fish and wildlife relates to subsistence and differential patterns of subsistence, 

and means differences in rates and/or patterns of fish, water, vegetation and/or wildlife 

consumption among minority populations, low-income populations, or Native American tribes, as 

compared to the general populations. As a response to Executive Order 12898, the 1999 National 

Academy of Sciences publication noted the following (Institute of Medicine, 1999, p. 17):

... differences in behavior, employment, and lifestyles among subgroups in the 

population may result in differences in exposure. For example, among the Alutiiq, Yup’ik, 

and Inupiat Alaskan Native peoples, the yearly intake of wild foods per person is between 

171 and 272 kilograms (375 and 600 pounds). Increasing evidence of certain 

contaminants such as mercury in the wild food supply of these Alaskan Natives has been 

exhibited by methyl mercury levels that exceed those provisionally established as safe by 

the World Health Organization.

 

56 Presidential Executive Order 12898: Federal Actions To Address Environmental Justice In Minority Populations and Low-Income 

Populations. Signed by President William J. Clinton, February 11, 1994 web location: http://www.epa.gov/region2/ej/exec_order_12898.pdf
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Tribal subsistence exposure scenario and fishers: “Subsistence” refers to the hunting, fishing, 

and gathering activities that are fundamental to the way of life of many indigenous peoples

(Confederated Tribes of the Umatilla Indian Reservation, 2004, p. 4). Subsistence utilizes 

traditional, small-scale technologies for harvesting and preserving foods as well as for 

distributing the produce through communal networks of sharing and bartering. Because it often 

misinterpreted, an explanation of “subsistence” is taken from the National Park Service

(Confederated Tribes of the Umatilla Indian Reservation, 2004): 

While non-natives tend to define subsistence in terms of poverty or the minimum amount 

of food necessary to support life, native people equate subsistence with their culture. 

Among many tribes, maintaining a subsistence lifestyle has become the symbol of their 

survival in the face of mounting political and economic pressures. It defines who they are 

as a people. To Native Americans who continue to depend on natural resources, 

subsistence is more than eking out a living. While it is important to the economic wellbeing of their communities, the subsistence lifestyle is also the basis of cultural existence 

and survival. It is a communal activity. It unifies communities as cohesive functional 

units through collective production and distribution of the harvest. Some groups have 

formalized patterns of sharing, while others do so in more informal ways. Entire families 

participate, including elders, who assist with less physically demanding tasks. Parents 

teach the young to hunt, fish, and farm. Food and goods are also distributed through 

native cultural institutions. Most require young hunters to distribute their first catch 

throughout the community. Subsistence embodies cultural values that recognize both the 

social obligation to share as well as the special spiritual relationship to the land and 

resources. This relationship is portrayed in native art and in many ceremonies held 

throughout the year.

57

The average subsistence adult fish consumption rate is 620 g/day (500 pounds/year) for the 

Confederated Tribes of the Umatilla Indian Reservation.58

Usual and Accustomed Fishing Areas: also referred to as U & A areas or U & A fishing areas. 

The term refers to the 1854 and 1855 negotiated treaties with the Pacific Northwest Native 

Americans in Washington state: “The right of taking fish at usual and accustomed grounds and 

stations is further secured to said Indian in common with all citizens of the Territory...” 

 

57 National Park Service. Archeology Program. Preservation On the Reservation [And Beyond] Web location:

http://www.nps.gov/archeology/cg/fa_1999/Subsist.htm

58 Traditional Tribal Subsistence Exposure Scenario and Risk Assessment Guidance Manual. August 2007. Appendix 3: Fish Consumption 

Rate. Web location: http://www.hhs.oregonstate.edu/ph/tribal-grant-main-page2
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Appendix E: References

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Appendix E

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