NOAA Technical Memorandum NMFS-NWFSC-76

Status Review

of Cherry Point Pacific Herring

(Clupea pallasii)

and Updated Status Review

of the Georgia Basin Pacific Herring

Distinct Population Segment

under the Endangered Species Act

June 2006

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service
NOAA Technical Memorandum

NMFS Series

The Northwest Fisheries Science Center of the National 

Marine Fisheries Service, NOAA, uses the NOAA Technical Memorandum NMFS series to issue informal scientific 

and technical publications when complete formal review

and editorial processing are not appropriate or feasible due

to time constraints. Documents published in this series may

be referenced in the scientific and technical literature. 

The NMFS-NWFSC Technical Memorandum series of the 

Northwest Fisheries Science Center continues the NMFSF/NWC series established in 1970 by the Northwest &

Alaska Fisheries Science Center, which has since been 

split into the Northwest Fisheries Science Center and the

Alaska Fisheries Science Center. The NMFS-AFSC Technical Memorandum series is now being used by the Alaska 

Fisheries Science Center. 

Reference throughout this document to trade names does

not imply endorsement by the National Marine Fisheries

Service, NOAA. 

This document should be cited as follows:

Gustafson R.G., J. Drake, M.J. Ford, J.M. Myers, E.E. 

Holmes, and R.S. Waples. 2006. Status review of Cherry 

Point Pacific herring (Clupea pallasii) and updated status 

review of the Georgia Basin Pacific herring distinct population segment under the Endangered Species Act. U.S. 

Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-76, 

182 p. 
NOAA Technical Memorandum NMFS-NWFSC-76

Status Review

of Cherry Point Pacific Herring

(Clupea pallasii)

and Updated Status Review

of the Georgia Basin Pacific Herring

Distinct Population Segment

under the Endangered Species Act

Richard G. Gustafson, Jonathan Drake, Michael J. Ford,

James M. Myers, Elizabeth E. Holmes, and Robin S. Waples

Northwest Fisheries Science Center

2725 Montlake Boulevard East

Seattle, Washington 98112

June 2006

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service
Most NOAA Technical Memorandums

NMFS-NWFSC are available online at the 

Northwest Fisheries Science Center

web site (http://www.nwfsc.noaa.gov)

Copies are also available from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

phone orders (1-800-553-6847)

e-mail orders (orders@ntis.fedworld.gov)

ii 
Table of Contents 

List of Figures...............................................................................................................................................v

List of Tables ...............................................................................................................................................ix

Executive Summary .....................................................................................................................................xi

Acknowledgments.....................................................................................................................................xvii

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

Scope and Intent of Present Document.....................................................................................................2

Key Questions in ESA Evaluations..........................................................................................................2

Summary of Information Presented by the Petitioners.............................................................................4

Approaches to the Species Question.............................................................................................................8

Life History and Morphology...................................................................................................................8

Marine Zoogeographic Provinces.............................................................................................................9

Genetic Methods.......................................................................................................................................9

Herring and the Metapopulation Concept ................................................................................................9

DPS Determination for Cherry Point Pacific Herring.................................................................................12

BRT DPS Deliberations Process ............................................................................................................12

BRT Determinations of ESA Discreteness and Significance .................................................................12

Evidence Supporting Discreteness and Significance Decisions.............................................................13

Final DPS Determination .......................................................................................................................67

Approaches to Evaluating Risk of Extinction.............................................................................................69

The “Extinction Risk” Question.............................................................................................................69

Factors for Decline .................................................................................................................................69

Previous Cherry Point Pacific Herring Risk Assessments .....................................................................70

Previous BRT Risk Assessment Methods..............................................................................................71

Risk Assessment Methods......................................................................................................................71

Risk Assessment.....................................................................................................................................77

Application of IUCN Categories..........................................................................................................112

Results of Modified Risk Matrix for the Georgia Basin Pacific Herring DPS.....................................112

Risk Determination...............................................................................................................................117

Significant Portion of the Range of the Georgia Basin DPS Question .....................................................118

iii
Previous Findings on the “Significant Portion of its Range” Question................................................118

Approaches to the “Significant Portion of its Range” Question...........................................................118

Evidence for Demographically Independent Subpopulations ..............................................................119

Possible Subpopulations in the Georgia Basin DPS.............................................................................132

Extinction Risk of Possible Subpopulations in the Georgia Basin DPS...............................................135

Conclusions: Risk Assessment .................................................................................................................150

Glossary ....................................................................................................................................................155

References.................................................................................................................................................161

iv
List of Figures 

Figure 1. Regional water masses of Puget Sound and geographical locations mentioned in the text .......15

Figure 2. Geographical location of Cherry Point and other localities mentioned in the text.....................16

Figure 3. Geographical locations in the Strait of Georgia and on the southern coast of British 

Columbia mentioned in the text..................................................................................................................17

Figure 4. DFO Pacific herring sections in the six regions of British Columbia ........................................20

Figure 5. Pacific herring spawn timing observations by DFO herring sections in the British 

Columbia Strait of Georgia herring management region from 1928 to 2004 .............................................21

Figure 6. Pacific herring spawn timing observations by DFO herring sections in the British 

Columbia Johnstone Strait herring management region from 1928 to 2004 ..............................................22

Figure 7. Pacific herring spawn timing observations by DFO herring sections in the British 

Columbia West Coast Vancouver Island herring management region from 1928 to 2004 ........................23

Figure 8. Pacific herring spawn timing observations by DFO herring sections in the British 

Columbia Central Coast herring management region from 1928 to 2004 ..................................................24

Figure 9. Pacific herring spawn timing observations by DFO herring sections in the British 

Columbia Queen Charlotte Islands and North Coast herring management region from 1928 

to 2004 .......................................................................................................................................................25

Figure 10. Geographic distribution of WDFW Pacific herring stocks and herring sections 

in the Canadian SOG ..................................................................................................................................29

Figure 11. Geographical distribution of major Pacific herring spawning locations in southern 

British Columbia.........................................................................................................................................32

Figure 12. Geographic distribution of major Pacific herring spawning locations on the northern 

and north-central coast of British Columbia ...............................................................................................33

Figure 13. Pacific herring sampling sites and associated graphical symbols necessary

for interpretation of Figures 14–19 and 22–27. ..........................................................................................35

Figure 14. Mean length-at-age for 3-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................36

Figure 15. Mean length-at-age for 4-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................37

Figure 16. Mean length-at-age for 5-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................38

Figure 17. Mean length-at-age for 6-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................39

Figure 18. Mean length-at-age for 7-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................40

v
Figure 19. Mean length-at-age for 8-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................41

Figure 20. Comparisons of adjusted least squares means and standard errors of length 

for age-3 Pacific herring over the period 1990–2002 from West Coast Vancouver Island, 

Canadian SOG, and Washington State..... .................................................................................................42

Figure 21. Comparisons of adjusted least squares means and standard errors of length 

for age-6 Pacific herring over the period 1990–2002 from West Coast Vancouver Island, 

Canadian SOG, and Washington State..... .................................................................................................43

Figure 22. Mean weight-at-age for 3-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................44

Figure 23. Mean weight-at-age for 4-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................45

Figure 24. Mean weight-at-age for 5-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................46

Figure 25. Mean weight-at-age for 6-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................47

Figure 26. Mean weight-at-age for 7-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................48

Figure 27. Mean weight-at-age for 8-year-old Pacific herring spawners sampled from 1990 

to 2002 on spawning grounds with seine or trawl gear...............................................................................49

Figure 28. Comparisons of adjusted least squares means and standard errors of weight 

for age-3 Pacific herring over the period 1990–2002 from West Coast Vancouver Island, 

Canadian SOG, and Washington State..... .................................................................................................50

Figure 29. Comparison of adjusted least squares means and standard errors of weight 

for age-6 Pacific herring over the period 1990–2002 from West Coast Vancouver Island, 

Canadian SOG, and Washington State..... .................................................................................................51

Figure 30. Comparisons of adjusted least squares means and standard errors of length 

for Pacific herring over the period 1976–1980 at Cherry Point, Washington, and in British 

Columbia at Nootka Sound, West Barkley Sound, Baynes Sound, Lund, Qualicum, French Creek, 

Nanoose Bay, and Other Area 18................................................................................................................57

Figure 31. Comparisons of adjusted least squares means and standard errors of weight 

for Pacific herring over the period 1976–1980 at Cherry Point, Washington, and in British 

Columbia at Nootka Sound, West Barkley Sound, Baynes Sound, Lund, Qualicum, French Creek, 

Nanoose Bay, and Other Area 18................................................................................................................58

Figure 32. Cherry Point Pacific herring age composition of spawners in 1936–1937 and 1973–2004.....60

Figure 33. Recovery location of four of 797 herring tagged at Birch Bay on 22 April 1938 ....................62

Figure 34. Approximate recovery locations of eight of the over 18,000 herring tagged at Cherry

Point in 1981 and 1982 ...............................................................................................................................62

Figure 35. Generalized geographical boundary of the Georgia Basin Pacific herring distinct 

population segment. ....................................................................................................................................68

Figure 36. Cherry Point herring spawning stock and fishery catch biomass.............................................79

Figure 37. Number of Cherry Point Pacific herring at age from 1973 to 2004 .........................................83

vi
Figure 38. Cherry Point Pacific herring mean length-at-age for ages 2 through 9 from 1973 to 2004 .....84

Figure 39. Cherry Point Pacific herring mean weight-at-age for ages 2 through 9 from 1973 to 2004.....85

Figure 40. Short-term trend of Cherry Point Pacific herring spawner abundance from 1990 to 2004 ......87

Figure 41. Long-term trend of Cherry Point Pacific herring spawner abundance from 1973 to 2004 ......87

Figure 42. Kilometers of shoreline receiving late-spring Pacific herring spawn deposition at Point 

Roberts, Birch Point, Cherry Point, and Hale Passage ...............................................................................90

Figure 43. Georgia Basin Pacific herring DPS spawner biomass from 1973 to 2004 ...............................91

Figure 44. Short-term trend of Georgia Basin Pacific herring DPS spawner abundance from 1990 

to 2004..... ..................................................................................................................................................91

Figure 45. Long-term trend of Georgia Basin Pacific herring DPS spawner abundance from 1973 

to 2004...... ................................................................................................................................................92

Figure 46. Lambda estimates for the Cherry Point Pacific herring population and the posterior

probability that the subpopulation experiences a 95% decline in biomass within the next 10, 20, 

or 50 years...................................................................................................................................................94

Figure 47. Lambda estimates for the Georgia Basin Pacific herring DPS and the posterior 

probability that the subpopulation experiences a 95% decline in biomass within the next 10, 20, 

or 50 years...................................................................................................................................................95

Figure 48. Weighted average age of spawning Pacific herring in the Cherry Point Pacific herring 

population from 1973 to 2004...................................................................................................................114

Figure 49. Weighted average age of spawning Pacific herring in the Strait of Georgia region 

from 1973 to 2004.....................................................................................................................................115

Figure 50. Spawn timing of Pacific herring in British Columbia herring sections and in WDFW 

herring stock units.....................................................................................................................................121

Figure 51. Tagging and recovery locations of over 21,000 Pacific herring tagged on the spawning 

grounds at Holmes Harbor during March of 1953 and April of 1955–1957.............................................127

Figure 52. Tagging and recovery locations of over 7,300 Pacific herring tagged on the spawning 

grounds at Port Orchard-Port Madison during March of 1953–1955 .......................................................127

Figure 53. Tagging and recovery locations of 6,000 Pacific herring tagged on the spawning 

grounds at Quilcene Bay during April 1953 and 1956 .............................................................................128

Figure 54. Tagging and recovery locations of over 4,000 Pacific herring tagged on the spawning 

grounds at Semiahmoo Bay during March of 1958 ..................................................................................128

Figure 55. Geographic distribution of eight proposed subpopulations of Pacific herring 

in the Georgia Basin DPS .........................................................................................................................134

Figure 56. Cherry Point Pacific herring spawner biomass from 1973 to 2004........................................137

Figure 57. Strait of Juan de Fuca Pacific herring spawner biomass from 1973 to 2004..........................137

Figure 58. Bute Inlet Pacific herring spawner biomass from 1973 to 2004.............................................138

Figure 59. Eastern Strait of Georgia Inlets Pacific herring spawner biomass from 1973 to 2004...........138

Figure 60. South/Central Puget Sound Pacific herring spawner biomass from 1973 to 2004.................139

Figure 61. Squaxin Pass Pacific herring spawner biomass from 1973 to 2004 .......................................139

vii
Figure 62. North Strait of Georgia Pacific herring spawner biomass from 1973 to 2004 .......................140

Figure 63. North Puget Sound and South Strait of Georgia Pacific herring spawner biomass 

from 1973 to 2004.....................................................................................................................................140

Figure 64. Pacific herring long-term abundance trends and associated 95% confidence limits 

for the Georgia Basin DPS and proposed subpopulations in the Georgia Basin DPS. .............................141

Figure 65. Pacific herring short-term abundance trends and associated 95% confidence limits 

for the Georgia Basin DPS and proposed subpopulations in the Georgia Basin DPS. .............................141

Figure 66. Lambda estimates for the North SOG Pacific herring subpopulation and the posterior 

probability that the subpopulation experiences a 95% decline in biomass within the next 10, 20, 

or 50 years............................................................................................................. 143

Figure 67. Lambda estimates for the North Puget Sound plus South SOG Pacific herring 

subpopulation and the posterior probability that the subpopulation experiences a 95% decline 

in biomass within the next 10, 20, or 50 years..........................................................................................144

Figure 68. Lambda estimates for the South/Central Puget Sound Pacific herring subpopulation 

and the posterior probability that the subpopulation experiences a 95% decline in biomass within 

the next 10, 20, or 50 years. ......................................................................................................................145

Figure 69. Lambda estimates for the Strait of Juan de Fuca Pacific herring subpopulation 

and the posterior probability that the subpopulation experiences a 95% decline in biomass within 

the next 10, 20, or 50 years. ......................................................................................................................146

Figure 70. Lambda estimates for the Squaxin Pass Pacific herring subpopulation 

and the posterior probability that the subpopulation experiences a 95% decline in biomass 

within the next 10, 20, or 50 years...................................................................................................147

Figure 71. Kilometers of shoreline receiving Pacific herring spawn deposition in proposed 

subpopulations of the Georgia Basin Pacific herring DPS .......................................................................148

viii
List of Tables 

Table 1. Range and peak of documented spawn timing for WDFW Puget Sound Pacific herring

stocks... ......................................................................................................................................................19

Table 2. Herring spawn records in the Strait of Georgia with a start date equal or greater than 

the 120th day of the year..............................................................................................................................30

Table 3. Matrix of pairwise comparison probabilities for age-3 length data from 1990 to 2002 

as illustrated in Figure 20............................................................................................................................52

Table 4. Matrix of pairwise comparison probabilities for age-3 weight data from 1990 to 2002 

as illustrated in Figure 28............................................................................................................................53

Table 5. Matrix of pairwise comparison probabilities for age-6 length data from 1990 to 2002 

as illustrated in Figure 21............................................................................................................................55

Table 6. Matrix of pairwise comparison probabilities for age-6 weight data from 1990 to 2002 

as illustrated in Figure 29............................................................................................................................56

Table 7. British Columbia Pacific herring tag releases recovered in known Washington State 

location .......................................................................................................................................................63

Table 8. Template for the risk matrix used in BRT deliberations..............................................................76

Table 9. North Puget Sound herring biomass estimates ............................................................................80

Table 10. South/Central Puget Sound herring biomass estimates..............................................................81

Table 11. Age and year of millions of herring in the Cherry Point population .........................................82

Table 12. Estimates of long- and short-term trends and their 95% confidence intervals 

for Pacific herring in the Georgia Basin Pacific herring DPS. ...................................................................88

Table 13. Comparison of WDFW classifications of status of inland water Pacific herring 

populations of Washington based on three stock assessments....................................................................89

Table 14. Results of application of the IUCN decline criteria to possible subpopulations within

the Georgia Basin Pacific herring DPS.....................................................................................................113

Table 15. Pacific herring spawner biomass estimates for proposed subpopulations within 

the Georgia Basin DPS from 1973 to 2004...............................................................................................136

Table 16. Estimates of long- and short-term trends and their 95% confidence intervals 

for proposed subpopulations of Pacific herring in the Georgia Basin Pacific herring DPS. ....................142

ix
x
Executive Summary

In 2001 the National Marine Fisheries Service (NMFS) completed a status review of 

Pacific herring (Clupea pallasii Valenciennes, 1847) in Puget Sound under the U.S. Endangered 

Species Act (ESA). At that time, a Biological Review Team (BRT) concluded that spawning 

populations of Pacific herring from Puget Sound and the Strait of Georgia constituted the 

Georgia Basin Pacific herring distinct population segment (DPS), and that this DPS was neither 

in danger of extinction nor likely to become so in the foreseeable future throughout all or a 

significant portion of its range. 

On 22 January 2004 and 14 May 2004, NMFS received petitions seeking to list Pacific 

herring that spawn at Cherry Point, Washington (a subset of the Georgia Basin Pacific herring 

DPS), as a threatened or endangered “species” under the ESA. NMFS evaluated each petition to 

determine whether the petitioner provided “substantial information” as required by the ESA to 

list a species. Additionally, NMFS evaluated whether information contained in the petitions 

might support the identification of a DPS that might warrant listing as a species under the ESA. 

NMFS determined that the 22 January 2004 petition failed to present substantial scientific and 

commercial information indicating that the petitioned action may be warranted. However, the 

agency found that the supplemental information contained in the 14 May 2004 petition did 

present substantial scientific and commercial information, or cited such information in other 

sources, that the petitioned action may be warranted and, subsequently, NMFS initiated an 

updated status review of the Georgia Basin Pacific herring DPS with particular reference to 

Cherry Point Pacific herring. 

The Pacific herring BRT—consisting of scientists from the Northwest Fisheries Science 

Center, Alaska Fisheries Science Center, and the National Ocean Service—was reformed by 

NMFS, and the team reviewed and evaluated scientific information compiled by NMFS staff

from published literature and unpublished data. Information presented at a public meeting in 

November 2004 in Seattle, Washington, was also considered. The BRT also reviewed additional 

information submitted to the ESA Administrative Record. 

The BRT was charged with consideration of the following questions: 

1. In light of all information, including new information not available at the time of the last 

status review, does the Cherry Point Pacific herring stock meet the criteria necessary to 

be considered a DPS as defined by the joint National Oceanic and Atmospheric 

Administration (NOAA)-U.S. Fish and Wildlife Service (USFWS) DPS policy?

2. If not, what is the DPS that includes the Cherry Point stock?

3. Is the DPS to which the Cherry Point stock belongs in danger of extinction or likely to 

become so in the foreseeable future throughout all or a significant portion of its range? 

xi
In addition, the BRT was asked to consider whether any portion of the identified DPS(s) 

contribute significantly to the abundance, productivity, distribution, or diversity of the DPS, such 

that its loss would significantly impair the long-term viability of the DPS. Finally, the BRT was 

tasked with providing a description of threats to the viability of the identified DPS(s), including 

(if known) their source(s), severity, geographic scope, and relative contribution to survival risk. 

However, as was the case in the previous status review, the BRT did not attempt a rigorous 

analysis of threats and their relative contribution to survival risk. There are several reasons for 

this. 

1. The BRT chose to focus primarily on the question of whether a DPS is at risk rather than 

how it came to be at risk. Although the latter question is important, a population or DPS 

that has been reduced to low abundance will continue to be at risk for demographic and 

genetic reasons until it reaches a larger size, regardless of the reasons for its initial 

decline. Furthermore, in some cases, a factor that was important in causing the original

declines may no longer be an impediment to recovery. 

2. Unlike many ESA-listed species that face a single primary threat, Pacific herring face 

numerous potential threats throughout every stage of their life cycle. It is therefore 

relatively easy to simply list current and past potential threats to Pacific herring 

populations, but it is much more difficult to evaluate the relative importance of a wide 

range of interacting factors. 

3. Evaluating the degree to which historic factors for decline will continue to pose a threat 

in the future generally requires consideration of issues that are more in the realm of social 

science than biological science—such as whether proposed changes will be funded, and, 

if funded, will be implemented effectively. 

Although this report does not consider threats or factors for decline in a comprehensive 

way, the BRT did consider major risk factors that were identified in the previous status review 

and in the petition. Evaluation of conservation measures and making of a final listing 

recommendation for the DPS to which Cherry Point Pacific herring belongs is the responsibility 

of the NMFS Northwest Regional Office. 

Guidance on what constitutes a distinct population segment is provided by the joint 

NMFS-USFWS interagency policy on vertebrate populations. To be considered “distinct,” a 

population, or group of populations, must be “discrete” from the remainder of the species to 

which it belongs, and “significant” to the species to which it belongs as a whole. Discreteness 

and significance are further defined by the services in the following policy language (USFWSNMFS 1996, p. 4725). 

Discreteness: A population segment of a vertebrate species may be considered 

discrete if it satisfies either one of the following conditions: 

1. It is markedly separated from other populations of the same taxon as a consequence 

of physical, physiological, ecological, or behavioral factors. Quantitative measures of 

genetic or morphological discontinuity may provide evidence of this separation. 

2. It is delimited by international governmental boundaries within which differences in 

control of exploitation, management of habitat, conservation status, or regulatory 

mechanisms exist that are significant in light of section 4(a)(1)(D) of the Act. 

xii
Significance: If a population segment is considered discrete under one or more of 

the above conditions, its biological and ecological significance will then be

considered in light of Congressional guidance (see Senate Report 151, 96th 

Congress, 1st Session) that the authority to list DPSs be used “sparingly” while 

encouraging the conservation of genetic diversity. In carrying out this 

examination, the Services will consider available scientific evidence of the 

discrete population segment’s importance to the taxon to which it belongs. This 

consideration may include, but is not limited to, the following: 

1. Persistence of the discrete population segment in an ecological setting unusual or 

unique for the taxon, 

2. Evidence that loss of the discrete population segment would result in a significant gap 

in the range of a taxon, 

3. Evidence that the discrete population segment represents the only surviving natural 

occurrence of a taxon that may be more abundant elsewhere as an introduced 

population outside its historic range, or 

4. Evidence that the discrete population segment differs markedly from other 

populations of the species in its genetic characteristics. 

After consideration of the all available scientific data, the Pacific herring BRT concluded, 

nearly unanimously, that Cherry Point Pacific herring were “discrete” under the provisions of the 

joint NMFS-USFWS DPS policy. However, there was no support on the BRT for a finding that 

Cherry Point Pacific herring were “significant” to the taxon of Pacific herring as a whole, as 

defined in the joint NMFS-USFWS DPS policy. The BRT identified a variety of evidence to 

support its conclusion that Cherry Point Pacific herring are a discrete population, including 

locally unique spawn timing, occupation of a locally unusual exposed coastline for spawning, 

and physiological factors such as unusual growth rate characteristics for the locality and 

differential accumulation of toxic contaminants in relation to other local Puget Sound Pacific 

herring populations indicative of disparate rearing conditions compared to Pacific herring in 

Puget Sound proper. In regards to the significance question, the BRT noted that Pacific herring 

are widely distributed across the North Pacific Rim and have a large number of stocks distributed 

throughout their extensive range. The BRT also recognized that the occurrence of other Pacific 

herring stocks with unusual spawn timing for their area was not exceptional, and that other 

Pacific herring stocks also spawn on fairly exposed coastlines of inshore waters in the Pacific 

Northwest that can be subject to high-energy wave action. The previous Pacific herring BRT 

discussed the significance of the Cherry Point Pacific herring stock with respect to the taxon to 

which it belongs (i.e., the whole biological species, Clupea pallasii) and came to a similar 

finding as reported in the previous status review. 

The BRT considered up to seven possible DPS configurations that might conceivably 

incorporate the petitioned population (Cherry Point Pacific herring). A majority of the BRT 

supported retention of the current Georgia Basin Pacific herring DPS, as described in the 

previous status review. Although there was significant support on the BRT for a larger DPS than 

Georgia Basin, the BRT as a whole did not feel compelled by the evidence to enlarge the 

boundaries of the present DPS. The BRT determined that the Cherry Point Pacific herring 

population is part of the previously defined Georgia Basin Pacific herring DPS, which includes 

xiii
the marine waters of Puget Sound, the Strait of Georgia, and eastern Juan de Fuca Strait in both 

the U.S. and Canada. 

Available information (genetics, life history, tagging studies) suggests that population 

structure of Pacific herring roughly conforms to the classical concept of a metapopulation, in 

which local subpopulations are linked demographically by at least episodic migration, and 

extinction and recolonization of local subpopulations are common over ecological time frames. 

Available information also suggests that the Georgia Basin DPS of Pacific herring does not differ 

substantially in general features of biology from Pacific herring in other areas. Therefore, the 

BRT concluded that, as a reasonable approximation, the classical metapopulation model provides 

a framework for assessing extinction risk of the DPS. In order to explicitly address the 

“significant portion of its range question,” the BRT addressed the question, “Are subpopulation 

declines more pervasive and more pronounced than we would expect to find in a healthy 

metapopulation?” To evaluate this question, the BRT considered trends in eight different areas 

of the DPS, roughly defined on the basis of geography, life history, and genetics (Cherry Point, 

Squaxin Pass, South/Central Puget Sound, Strait of Juan de Fuca, Bute Inlet, Eastern Strait of 

Georgia [SOG] Inlets, Northern SOG, and North Puget Sound plus Southern SOG). Overall 

abundance is declining within some of these areas and increasing in others. These patterns of 

abundance and distribution within the Georgia Basin DPS appeared to be fairly typical of what is 

seen in other Pacific herring populations throughout northwestern North America, including 

many relatively pristine areas in southeastern Alaska and British Columbia. 

However, the BRT also identified reasons for concern about some local subpopulations 

within the DPS and some potential future developments that would increase risks to the DPS. 

First, metapopulation theory indicates that in source-sink systems the existence of sinks can 

buffer extinction risk of the entire metapopulation, compared to a scenario in which the sink 

areas cease to function at all. Second, the BRT recognized that the classical metapopulation 

concept does not perfectly fit the Georgia Basin Pacific herring DPS. The pattern of 

subpopulation structure in the DPS is more similar to the mixed structure metapopulation model 

than to a classical metapopulation. Although the DPS is characterized by high levels of 

homogeneity, the Cherry Point population and some subpopulations such as Squaxin Pass are 

relatively more distinctive, based on spawn timing, growth rate, contaminant profiles, and 

genetic differences. And as noted above, the BRT concluded that Cherry Point Pacific herring 

meets the DPS criteria to be considered a “discrete” population. These differences were not 

considered of a magnitude suggestive of long-term evolutionary divergence, but it was 

considered possible that demographic linkages between these and other subpopulations in the 

DPS are weak enough that they are largely demographically independent on ecological time

scales. If these subpopulations were lost, recolonization might take longer than it would for 

areas that are part of a classical metapopulation. Still, the BRT did not feel that current risks to 

these areas represent risks to a significant portion of the range of the DPS as a whole. 

Furthermore, overall abundance of the DPS is at historically high levels, and the number of 

kilometers of coastline used by Pacific herring for spawning has also been increasing. The BRT 

concluded that available evidence does not suggest unusual levels of risk to the DPS as a whole, 

nor to a significant part of the DPS. Therefore, the BRT concluded that the DPS is not at risk of 

extinction in all or a significant portion of its range, nor likely to become so in the foreseeable 

future. The approaches and conclusions taken by the BRT are consistent with previous NMFS 

xiv
status reviews, including the extensive reviews of Pacific salmon along the west coast of North 

America. 

Finally, the BRT noted that Pacific herring play important roles in the Georgia Basin 

ecosystem. If the fundamental biological processes necessary for Pacific herring were to be 

disrupted in the future, such that the metapopulation ceased to function effectively, the 

consequences for other species could be substantial. Although these consequences are difficult 

to predict, it is worth noting that Pacific herring are important forage fish for both Pacific salmon 

(Oncorhynchus spp.) and killer whales (Orcinus orca), so collapse of the Pacific herring DPS 

could have serious negative effects on these other protected species. 

xv
xvi
Acknowledgments 

The status review for Cherry Point Pacific herring was conducted by a team of scientists 

from the Northwest Fisheries Science Center (NWFSC), Alaska Fisheries Science Center 

(AFSC), and the National Ocean Service (NOS). This biological review team (BRT) relied on 

comments and informational reports submitted by the public and by state, tribal, and federal 

agencies. The authors acknowledge the efforts of all who contributed to this record, especially 

the Washington Department of Fish and Wildlife (WDFW) and Department of Fisheries and 

Oceans Canada (DFO). 

Numerous individual fishery scientists and managers provided information that aided in 

preparation of this document and deserve special thanks. We particularly wish to thank Drs. 

Jake Schweigert and Doug Hay of DFO, Pacific Biological Station, and Kurt Stick, Dr. Maureen 

Small, and Greg Bargmann of WDFW for updated information, data, opinions, and advice. We

also wish to thank three anonymous scientists whose peer review of this document provided 

added clarity. 

xvii
xviii
Introduction 

In 2001 the National Marine Fisheries Service (NMFS) completed a status review (Stout 

et al. 2001a) of Pacific herring (Clupea pallasii Valenciennes, 1847)1

 in response to a petition 

(Wright 1999) seeking to list 18 species of marine fishes, including Pacific herring, in Puget 

Sound under the U.S. Endangered Species Act (ESA). Following acceptance of the 1999 

petition (NMFS 1999), NMFS formed a Pacific herring Biological Review Team (BRT), 

consisting of scientists from the Northwest Fisheries Science Center, Alaska Fisheries Science 

Center (AFSC), National Ocean Service (NOS), and the U.S. Fish and Wildlife Service 

(USFWS) to determine whether Pacific herring in Puget Sound is a “species” under the ESA and, 

if so, whether the “species” is in danger of extinction (endangered) or likely to become so 

(threatened). Importantly, for vertebrates the ESA allows listing not only of species and 

subspecies, but also of distinct population segments (DPSs—see detailed discussion in The 

“Species” Question subsection on page 3). In 2001, the Pacific herring BRT concluded that 

spawning populations of Pacific herring from Puget Sound (including Cherry Point), the Strait of 

Georgia (SOG), and the Strait of Juan de Fuca in the U.S. and Canada constitute a Georgia Basin 

Pacific herring DPS (Stout et al. 2001a). In 2001, the Pacific herring BRT also concluded that 

the Georgia Basin DPS, containing the petitioned Puget Sound Pacific herring populations, was 

neither in danger of extinction nor likely to become so in the foreseeable future throughout all or 

a significant portion of its range (Stout et al. 2001a, NMFS 2001). 

On 22 January 2004 and 14 May 2004, NMFS received petitions seeking to list Pacific 

herring that spawn at Cherry Point, Washington, as a threatened or endangered species under the 

ESA. NMFS evaluated each petition to determine whether the petitioner provided substantial 

information as required by the ESA to list a species. The agency also reviewed other readily 

available information and consulted with state and tribal biologists to determine whether general 

agreement existed on the uniqueness, distribution, abundance, and threats to the petitioned stock. 

Additionally, NMFS evaluated whether available information might support the identification of 

a distinct population segment that might warrant listing as a species under the ESA. NMFS 

determined that the 22 January 2004 petition failed to present substantial scientific and 

commercial information indicating that the petitioned action may be warranted. However, the 

agency found that the supplemental information contained in the 14 May 2004 petition did 

present substantial scientific and commercial information, or cited such information in other 

sources, that the petitioned action may be warranted (NMFS 2004) and subsequently, NMFS 

initiated an updated status review of the Georgia Basin Pacific herring DPS with particular 

reference to Cherry Point Pacific herring. 

1

 Following Nelson et al. (2004), the specific name for Pacific herring is herein spelled –ii, the original spelling. 
2

 The BRT for Cherry Point Pacific herring consisted of the following members: Dr. Tracy Collier, Jonathan Drake, 

Dr. Michael Ford, Kurt Fresh, Dr. Richard Gustafson, Dr. Richard Methot, Dr. James Myers, Heather Stout, Donald

Van Doornik, and Dr. Robin Waples from NWFSC; Mark Carls from AFSC; and Dr. Alan Mearns from NOS. 

Scope and Intent of Present Document 

In order to meet the provision in the ESA that listing determinations be made with the

best available scientific and commercial information, NMFS formed a team of scientists with 

diverse backgrounds in marine fish biology and marine habitats to conduct this review. This 

reconstituted Pacific herring Biological Review Team (BRT)2 reviewed and evaluated scientific 

information compiled by NMFS’s staff from published literature and unpublished data. 

Information presented at a public meeting in November 2004 in Seattle, Washington, was also 

considered. The BRT also reviewed additional information submitted to the ESA Administrative 

Record. 

The BRT was charged with consideration of the following questions in helping NMFS

address whether Cherry Point Pacific herring is a DPS and whether the DPS containing Cherry 

Point Pacific herring is at risk of extinction throughout all or a significant portion of its range. 

1. In light of all information, including new information not available at the time of the last 

status review, does the Cherry Point Pacific herring stock meet the criteria necessary to 

be considered a DPS as defined by the joint NOAA-USFWS DPS policy (explained in 

The “Species” Question subsection on page 3)?

2. If not, what is the DPS that includes the Cherry Point stock?

3. Is the DPS to which the Cherry Point stock belongs in danger of extinction or likely to 

become so in the foreseeable future throughout all or a significant portion of its range? 

In order to explicitly address the question of whether the DPS containing the Cherry 

Point population was threatened or endangered in a significant portion of its range, the BRT was 

also asked to consider whether any portion of the identified DPS that contains Cherry Point 

Pacific herring contribute significantly to the abundance, productivity, distribution, or diversity 

of the DPS, such that its loss would significantly impair the long-term viability of the DPS. In 

addition the BRT was tasked with providing a description of threats to the viability of the 

identified DPS that contains Cherry Point Pacific herring, including (if known) their source(s), 

severity, geographic scope, and relative contribution to survival risk. 

Key Questions in ESA Evaluations

Two key questions must be addressed in determining whether a listing under the ESA is 

warranted: First, is the entity in question a species as defined by the ESA? Second, if so, is the 

species in danger of extinction (endangered) or likely to become so (threatened)? This document 

provides the conclusions of the BRT regarding both the identification of a Pacific herring DPS 

that incorporates Cherry Point Pacific herring and the risk of extinction to that DPS. 

2
The “Species” Question

As amended in 1978, the ESA allows listing of distinct population segments of 

vertebrates as well as named species and subspecies. Guidance on what constitutes a distinct 

population segment is provided by the joint USFWS-NMFS interagency policy on vertebrate 

populations (USFWS-NMFS 1996). This policy states that to be considered “distinct,” a 

population, or group of populations, must be “discrete” from the remainder of the species to 

which it belongs, and “significant” to the species to which it belongs as a whole. Discreteness 

and significance are further defined by the services in the following policy language (USFWSNMFS 1996, p. 4725). 

Discreteness: A population segment of a vertebrate species may be considered 

discrete if it satisfies either one of the following conditions: 

1. It is markedly separated from other populations of the same taxon as a 

consequence of physical, physiological, ecological, or behavioral factors. 

Quantitative measures of genetic or morphological discontinuity may provide 

evidence of this separation. 

2. It is delimited by international governmental boundaries within which 

differences in control of exploitation, management of habitat, conservation 

status, or regulatory mechanisms exist that are significant in light of section 

4(a)(1)(D) of the Act. 

Significance: If a population segment is considered discrete under one or more of 

the above conditions, its biological and ecological significance will then be

considered in light of Congressional guidance (see Senate Report 151, 96th 

Congress, 1st Session) that the authority to list DPS’s be used “sparingly” while 

encouraging the conservation of genetic diversity. In carrying out this 

examination, the Services will consider available scientific evidence of the 

discrete population segment’s importance to the taxon to which it belongs. This 

consideration may include, but is not limited to, the following: 

1. Persistence of the discrete population segment in an ecological setting unusual 

or unique for the taxon, 

2. Evidence that loss of the discrete population segment would result in a 

significant gap in the range of a taxon, 

3. Evidence that the discrete population segment represents the only surviving 

natural occurrence of a taxon that may be more abundant elsewhere as an 

introduced population outside its historic range, or 

4. Evidence that the discrete population segment differs markedly from other 

populations of the species in its genetic characteristics 

This joint USFWS-NMFS policy applies to all vertebrate species, and does not elaborate 

on the specific manner in which the information related to DPS status should be analyzed. 

NMFS has developed a policy on the kinds of evidence that can be considered to evaluate 

distinctiveness of populations in Pacific salmon species (Oncorhynchus spp.) (Waples 1991a, 

3
1991b, 1995), and similar kinds of evidence can be used to assess distinctiveness of populations 

or groups of populations of marine fishes. This Pacific salmon policy (Waples 1991a, 1991b, 

1995) advocates a holistic approach in which all available information is considered, as well as a 

consideration of the strengths and limitations of such information in delineating distinct 

population segments. Important information includes natural rates of migration and 

recolonization, evaluations of the efficacy of natural barriers to migration, and measurements of 

genetic differences between populations. Data from protein electrophoresis and DNA analyses 

can be particularly useful for determining distinctiveness, because gene frequency differences 

among populations may reflect limited gene flow between areas. 

The joint USFWS-NMFS policy states that international boundaries within the 

geographical range of the species may be used to delimit a distinct population segment in the 

United States. This criterion is applicable if differences in the control of exploitation of the 

species, the management of the species’ habitat, the conservation status of the species, or 

regulatory mechanisms differ between countries that would influence the conservation status of 

the population segment in the United States. However, in past assessments of evolutionarily 

significant units (ESUs) in Pacific salmon and DPSs in marine fish, NMFS has placed the 

emphasis on biological information in defining DPSs and has considered political boundaries 

only at the implementation of ESA listings. Therefore, the BRT focused on biological 

information in identifying DPSs of Pacific herring, regardless of political boundaries. 

Extinction Risk 

The ESA (Section 3) defines the term endangered species as “any species which is in 

danger of extinction throughout all or a significant portion of its range.” The term threatened 

species is defined in the same section of the ESA as “any species which is likely to become an 

endangered species within the foreseeable future throughout all or a significant portion of its 

range.” The ESA states that a variety of information should be used in evaluating the level of 

risk faced by a species or a DPS, including: 

1) The present or threatened destruction, modification, or curtailment of its habitat or range, 

2) Overutilization for commercial, recreational, scientific, or educational purposes, 

3) Disease or predation, 

4) The inadequacy of existing regulatory mechanisms, and 

5) Other natural or man-made factors affecting its continued existence. 

According to the ESA, the determination of whether a species is threatened or endangered should 

be made on the basis of the best scientific information available on its current status, after taking 

into consideration conservation measures that are proposed or are in place. 

Summary of Information Presented by the Petitioners 

On 22 January 2004, NMFS received a petition from the Center for Biological Diversity 

and copetitioners (Center for Biological Diversity et al. 2004) to designate the Cherry Point Pacific 

herring stock as a DPS and list it as a threatened or endangered species and to designate critical 

habitat under the ESA. On 14 May 2004, the same petitioners submitted additional scientific 

4
information (Werntz 2004) regarding the stock structure of the Cherry Point and other Pacific 

Northwest Pacific herring stocks. NMFS treated the two submissions as separate petitions and 

evaluated each one to determine whether they presented substantial scientific or commercial 

information indicating that the petitioned actions may be warranted. Section 424.14(b)(1) of 

NMFS ESA implementation regulations defines “substantial information” as the amount of 

information that would lead a reasonable person to believe that the measure proposed in the 

petition may be warranted. Section 424.14(b)(2) of these regulations lists factors to be 

considered in evaluating the petition, including whether the petition contains detailed narrative 

justification for the recommended measure, a description of past and present numbers of 

geographical distributions of the species, and a description of threats facing the species. 

NMFS found that the 22 January 2004 petition failed to present substantial scientific and 

commercial information indicating that the petitioned action was warranted. However, NMFS 

found that the 14 May 2004 petition did present substantial scientific and commercial 

information indicating that the petitioned action may be warranted. Information presented in 

either petition that is deemed pertinent to the DPS questions of discreteness and significance and 

to the extinction risk question will be summarized herein. 

The majority of the physical, physiological, ecological, and behavioral evidence for 

separation of Cherry Point Pacific herring from other populations, as cited by the petitioners, was 

considered by the BRT at the time of the previous status review of Puget Sound Pacific herring 

(Stout et al. 2001a). Pertinent data and studies cited by the petitioners that was not available at 

the time of the previous status review included: 1) microsatellite DNA information in Beacham

et al. (2001), 2) microsatellite DNA information in Small et al. (2004), 3) a stable isotope study 

of Pacific herring otoliths (Gao et al. 2001), 4) spawner biomass estimates for Cherry Point 

Pacific herring from 2001 to 2004, and 5) citation of various oral presentations that occurred at 

the 2002 Herring Summit and Pacific Coast Herring Workshop held in Bellingham, Washington. 

The DPS Question: Summary of Evidence for “Discreteness” 

The petitioners argued that the Cherry Point Pacific herring stock should be considered 

discrete due to “unique genetic characteristics, physiology, diet and spawning behavior, and 

other factors” (Center for Biological Diversity et al. 2004, p. 29) that indicate it is markedly 

separated from other Pacific herring stocks. In particular, the petitioners claimed that recent 

microsatellite DNA studies cited as Beacham et al. (2001), Beacham (2002), and Small et al. 

(2004) show Cherry Point Pacific herring to be genetically distinct from other Pacific herring 

stocks in the Puget Sound and Strait of Georgia. In addition, the petitioners cited Gao et al. 

(2001) as evidence of marked physiological separation of the Cherry Point stock. Gao et al. 

(2001) analyzed oxygen and carbon isotope ratios in otoliths (ear bones) from spawning Pacific 

herring collected at Cherry Point, and at Port Orchard and Squaxin Pass in south Puget Sound. 

The petitioners agued that the Gao et al. (2001) study indicates that early rearing of Cherry Point 

Pacific herring occurs in a different environment than other Puget Sound Pacific herring 

populations and that young Cherry Point Pacific herring remain in estuarine environments and do 

not migrate offshore. The petitioners also argued that the Cherry Point stock is markedly 

separated from other Pacific herring by a higher average infection rate with certain parasites 

compared to other stocks of Pacific herring; by a juvenile diet that may differ from other Puget 

Sound stocks; by the physical separation of its “spawning grounds” (Center for Biological 

5
Diversity et al. 2004, p. 29) from other Pacific herring; by its ability to spawn in a relatively 

open, high-energy shoreline habitat; and by its late spawning period (early April to early June), 

relative to other Pacific herring in Puget Sound that spawn in protected waters from mid-January 

to mid-April. 

The DPS Question: Summary of Evidence for “Significance” 

The petitioners argued that the Washington Department of Fish and Wildlife (WDFW) 

Cherry Point Pacific herring stock is significant to the species as a whole based on its persistence 

in an ecological setting that is unusual and unique to Pacific herring, on its genetic differentiation 

from other populations as reported in Beacham et al. (2001) and Small et al. (2004), and by its 

reported significance to the health and function of the Puget Sound ecosystem. The petitioners 

further argued that the distinctly different spawn timing of Cherry Point Pacific herring, which 

leads to different relationships with prey and predators, indicates the presence of characteristics 

that may be “essential for continued evolution and survival of the Pacific herring species” 

(Center for Biological Diversity et al. 2004, p. 34). 

Summary of Abundance and Population Trends 

The petitioners cited historical abundance data for the Cherry Point Pacific herring stock 

from 1973 to 2000 that indicated a decline of 94% in the stock biomass, from a high of almost 

15,000 to a low of 800 short tons. The petitioners also presented three years of population 

abundance data (2001–2003) for Cherry Point Pacific herring that has appeared since the 

previous status review. The population has shown an increasing trend over these three years, 

with the 2003 spawner biomass estimate of 1,611 short tons reaching its highest level since 1996. 

The petitioners also pointed out that WDFW sets the number of spawners that they feel 

necessary for the population to replace itself and sustain a harvest at 3,200 short tons, 

approximately twice the current abundance level. The petitioners acknowledged that the recent 

increase in abundance may be “in response to the increased ocean productivity associated with 

the Pacific Decadal Oscillation (PDO)” (Center for Biological Diversity et al. 2004, p. 9). 

The petitioners cited Bargmann (2001) for evidence that recent recruitment of Cherry 

Point Pacific herring into the spawning population has been below average (1,000 tons versus an 

average of 2,000 tons), although recruitment from the 2000 broodyear “was quite effective” 

(Center for Biological Diversity et al. 2004, p. 10). The petitioners argued that a “recruitment 

class failure” (Center for Biological Diversity et al. 2004, p. 10) could result in a precipitous 

decline in Cherry Point Pacific herring abundance. 

Summary of Risk Factors 

Major concerns of the petitioners included 1) reduction and degradation of Cherry Point 

Pacific herring habitat by industrial development and pollution, 2) compression of the age 

structure, and 3) increased depensatory mortality due to increased predation and fishing pressure 

on smaller schools. The petitioners in particular highlighted threats to Cherry Point Pacific 

herring from industrial activity near the spawning beaches. The petitioners’ list of industrial 

activities included dock construction and operation, outfall discharge, increased vessel traffic, 

accidental oil spills, noise pollution, introduction of nonindigenous aquatic species resulting 

6
from ballast water discharge, and release of biocides that are often used to treat ballast water 

prior to discharge. 

Summary of New Information Sources—Not Included in the Petition

Numerous studies that were not cited by the petitioners and that were not available at the 

time of the previous status review were consulted. These included 1) published scientific 

literature (Hay et al. 2001a, Hay and McKinnell 2002) and fisheries agency reports (Schweigert 

and Flostrand 2000, Flostrand and Schweigert 2002, 2003, 2004) summarizing results of Pacific 

herring tagging operations in British Columbia; 2) a series of four fisheries agency reports 

summarizing the metapopulation structure of British Columbia Pacific herring (Ware et al. 2000, 

Ware and Schweigert 2001, 2002, Ware and Tovey 2004); 3) an updated version of Beacham’s 

microsatellite DNA study of population structure of British Columbia Pacific herring (Beacham

et al. 2002); 4) a series of two peer-reviewed (Hart Hayes and Landis 2004, Landis et al. 2004) 

and two nonpeer-reviewed (Landis et al. 2000, Markiewicz et al. 2001) risk assessments of the 

Cherry Point Pacific herring stock; 5) an independent assessment of the Strait of Georgia Pacific 

herring roe fishery (Wallace and Glavin 2003); 6) a series of annual qualitative surveys of the 

Cherry Point shoreline (Kyte 1999, 2000, 2001, 2002, 2003, 2004); 7) a study documenting an 

increased incidence of a protistan parasite in older Puget Sound Pacific herring (Hershberger 

et al. 2002); and 8) a series of fisheries agency annual stock assessments of British Columbia 

Pacific herring (Schweigert 2001, 2002, 2004). 

7
Approaches to the Species Question 

The BRT considered several kinds of information to attempt to delineate DPSs of Pacific 

herring. The first kind of information considered was geographical variability in life history 

characteristics and morphology. Such traits usually have an underlying genetic basis, but are 

often strongly influenced by environmental factors from one locality to another. Information 

related to this category included patterns of marine species’ distribution (zoogeography) that may 

indicate changes in the physical environment that are shared with the species under review. The 

second kind of information consisted of tag and recapture studies, which give insight into the 

physical movement of individuals between areas. The third kind of information consisted of 

traits that are inherited in a predictable way and remain unchanged throughout the life of an 

individual. Differences among populations in the frequencies of markers at these traits may 

reflect isolation between the populations. In all studies of population structure, investigators 

should strive to compare data gathered from spawning aggregations of fish to avoid the potential 

for sampling from stock or population mixtures. The analyses of the above types of information 

are discussed briefly in the following sections. 

Life History and Morphology 

Isolation between populations may be reflected in several variables, including differences 

in life history variables (e.g., spawning timing, seasonal migrations), spawning location, parasite 

incidence, growth rates, morphological variability (e.g., morphometric and meristic traits), and 

demography (e.g., fecundity, age structure, length and age at maturity, mortality), among others. 

Although some of these traits may have a genetic basis, they are usually also strongly influenced 

by environmental factors over the lifetime of an individual or over a few generations. 

Differences can arise among populations in response to environmental variability among areas 

and can sometimes be used to infer the degree of independence among populations or 

subpopulations. Begg et al. (1999) have emphasized the necessity to examine the temporal 

stability of life history characteristics in order to determine whether differences between 

populations persist across generations. Many life history differences are often not correlated 

with variation at neutral molecular genetic markers, either indicating that they are 

environmentally influenced, or that patterns of genetic adaptation differ from patterns of gene 

flow and drift that are the primary factors influencing neutral molecular markers. 

The analysis of applied or acquired tags can indicate the degree of migration between 

localities. These tags include physical tags that are attached to a fish and later recovered, 

parasites that are characteristic of specific regions because of differential resistance or

occurrence, and elemental profiles that reflect local environmental conditions or diets. These 

tags provide evidence of movement of individuals from one place to another, but not necessarily 

of population connectivity through gene flow. Because these kinds of population markers are 

not inherited, they must be applied each generation or must arise naturally anew each generation. 

8
Marine Zoogeographic Provinces 

Ekman (1953), Hedgpeth (1957), Briggs (1974), and Allen and Smith (1988) summarized 

the distribution patterns of coastal marine fishes and invertebrates and defined major worldwide 

zoogeographic zones or provinces. The coastal region from Puget Sound to Sitka, Alaska, was 

considered a transition zone and could be classified as part of either of two provinces recognized 

by Briggs (1974): Aleutian or Oregonian. The southern boundary of the Oregonian Province is 

generally recognized as Point Conception, California, and the northern boundary of the Aleutian 

Province is similarly recognized as either Nunivak or the Aleutian Islands (Allen and Smith 

1988). Briggs (1974) placed the boundary between the Oregonian and Aleutian Provinces at 

Dixon Entrance in southern Southeast Alaska, based on the well-studied distribution of mollusks, 

but indicated that distributions of fishes, echinoderms, and algae gave evidence for placement of 

this boundary in the vicinity of Sitka, Alaska. Peden and Wilson (1976) investigated the 

distributions of inshore fishes in British Columbia and found Dixon Entrance to be of minor 

importance as a barrier to fish distribution. A more likely boundary between these faunas was 

suggested to occur near either Sitka, Alaska, or Cape Flattery, Washington (Peden and Wilson 

1976, Allen and Smith 1988). 

Genetic Methods 

Differences in life history traits among populations may provide little information on 

reproductive isolation between populations, because the genetic basis of many phenotypic and 

life history traits is unknown. The BRT also considered molecular genetic evidence that might 

be used to define reproductively isolated populations or groups of populations of fish in Puget 

Sound. Most molecular genetic markers appear to be largely unaffected by natural selection, so 

that geographical differences in gene frequencies can be interpreted in terms of gene flow and 

genetic drift. The analysis of the geographical distributions of these markers may reveal 

historical dispersals, equilibrium levels of migration (gene flow), and past isolation. Commonly, 

evidence for genetic population structure is based on the analysis of protein variants (allozymes), 

microsatellite loci (variable numbers of short tandem DNA repeats), and mitochondrial DNA 

(mtDNA). 

Herring and the Metapopulation Concept 

A metapopulation was defined by Levins (1970, p. 105) as: 

a population of populations which go extinct locally and recolonize. A region is 

suitable for a metapopulation if the mean extinction rate is less than the migration 

rate. 

As envisioned by Levins (1969, 1970), two of the central characteristics of a metapopulation 

were that local subpopulations are linked by migration and are subject to periodic extinction 

(extirpation) and recolonization. Consequently, not all suitable habitats would be simultaneously 

occupied. Levins’ ideal metapopulation included the assumptions that subpopulations have 

independent dynamics, that the exchange rate between subpopulations is so low that it has no 

affect on local subpopulation dynamics, and that all habitat patches have equal isolation and 

equal area (Levins 1970). In practice, most of Levins’ assumptions have been relaxed and no 

9
real metapopulation has been identified that satisfies all these criteria (Hanski and Simberloff

1997). 

Hanski and Simberloff (1997) have emphasized that local subpopulations within a 

metapopulation are spatially structured and migration among the subpopulations has some effect 

on local subpopulation dynamics. Harrison and Taylor (1997) noted that the underlying concept 

in the many refinements to Levins’ metapopulation model is that “persistence of species depends 

on their existence as sets of local populations, largely independent yet interconnected by 

migration” (Harrison and Taylor 1997, p. 27). Kritzer and Sale (2004) advocated that linkage of 

local- and regional-scale population processes beyond extinction-recolonization analysis can be 

considered under the metapopulation concept for marine fishes. Kritzer and Sale (2004) argued 

that “the critical feature of metapopulations is the coupling of spatial scales, whereby local 

populations experience partially independent dynamics but receive some identifiable 

demographic influence from other populations” (Kritzer and Sale 2004, p. 138). 

Under the metapopulation concept of Atlantic herring (Clupea harengus) population 

structure proposed by McQuinn (1997), local Atlantic herring populations may be perpetuated 

through a process he termed the “adopted-migrant hypothesis” (McQuinn 1997, p. 298), where 

juvenile Atlantic herring that associate with and synchronize their maturation with schools of 

adult Atlantic herring will adopt the migration and homing patterns of the adults. Thus local 

spawning populations are maintained by “repeat rather than natal homing to spawning areas, 

while local population persistence is ensured through the social transmission of migration 

patterns and spawning areas from adults to recruiting individuals” (McQuinn 1997, p. 298). In 

McQuinn’s (1997) adopted-migrant hypothesis, hydrographic forces on larvae and the effects of 

schooling of juveniles leads to the majority of individuals spawning in their native population. 

Thus differences in the mean values of meristic and morphometric measurements that reflect 

environmental differences during development are maintained, although strays from other 

populations are adopted by local populations and gene flow is significant (McQuinn 1997). 

McQuinn (1997) stated that the adopted-migrant hypothesis is consistent with genetic studies on 

Atlantic herring that have not observed temporally persistent differences, since no genetic 

differences would be expected between Atlantic herring populations with the hypothesized level 

of gene flow. Although McQuinn’s (1997) metapopulation concept and adopted-migrant 

hypothesis were first formulated for Atlantic herring, they have equal application in the case of 

Pacific herring. Along these lines, Ware and co-authors (Ware et al. 2000, Ware and Schweigert 

2001, 2002, Ware and Tovey 2004) have provided evidence indicating that the major migratory 

stocks of Pacific herring in British Columbia “are spatially structured and interact as a 

metapopulation” (Ware and Tovey 2004, p. 1). Dispersal rate and straying in both Atlantic 

(Huse et al. 2002) and Pacific herring (Ware and Schweigert 2002) appear to be density 

dependent and increase with abundant recruitment, resulting in periodic waves of dispersal that 

radiate throughout the metapopulation. 

Evidence supporting the hypothesis that the five major migratory stocks of British 

Columbia Pacific herring form a spatially structured metapopulation include: 1) the spatially 

fragmented distribution of spawning habitat (Hay et al. 1989, Ware et al. 2000, Hay and 

McCarter 2004a), 2) evidence of disappearance and recolonization events (Ware and Tovey 

2004), 3) evidence of significant migration (straying) between the five main stock assessment 

regions as indicated by tagging data (Hay et al. 1999, 2001a, Ware et al. 2000), and 4) high 

10
levels of gene flow as shown by DNA microsatellite analyses (Beacham et al. 2001, 2002). 

Smedbol et al. (2002) proposed that to be considered a metapopulation a system must meet the 

following two criteria: 1) local populations must be shown to exchange low levels of individuals, 

and 2) extinction and recolonization must be documented. Both of these metapopulation criteria 

have been met for Georgia Basin Pacific herring. Many authors (McQuinn 1997, Ware et al. 

2000, Smedbol et al. 2002, Smedbol and Wroblewski 2002) have emphasized that local 

subpopulations should be considered the basic fisheries management units and that conservation 

of subpopulation structure is essential for the preservation of spawning potential and genetic and 

life history diversity. 

11
3

 J. West, Washington Dept. Fish and Wildlife, Marine Resources Division, Olympia, WA. Pers. commun., 30 Nov. 

2004. 

DPS Determination for Cherry Point 

Pacific Herring 

BRT DPS Deliberations Process 

Extensive documentation of Pacific herring life history information and environmental 

features of Puget Sound and the Strait of Georgia considered relevant to the DPS discreteness 

and significance questions were presented in the previous Pacific herring status review (Stout 

et al. 2001a). This information included detailed reviews of Pacific herring spawn location, 

spawn timing, results of tagging experiments, seasonal migration patterns, larval retention areas, 

parasite incidence, growth rate, size-at-age, age structure, age-at-maturity, and morphological 

differentiation throughout the species range across the North Pacific Rim from San Diego, 

California to the Yellow Sea in Asia. Rather than duplicate this information, the following 

discussions will emphasize detailed information specifically relevant to the discreteness and 

significance decisions for Cherry Point Pacific herring. 

BRT Determinations of ESA Discreteness and Significance 

The BRT was nearly unanimous in its conclusion that Cherry Point Pacific herring 

represent a discrete population under the language of the joint USFWS-NMFS DPS policy. A 

small minority of the BRT concluded that Cherry Point Pacific herring are not discrete from the 

remainder of the species. The BRT identified a variety of evidence to support its conclusion that 

Cherry Point Pacific herring are a discrete population, including locally unique spawn timing, 

occupation of a locally unusual exposed coastline for spawning, and physiological factors such 

as unusual growth rate characteristics for the locality and differential accumulation of toxic 

contaminants in relation to other local Puget Sound Pacific herring populations indicative of 

disparate rearing conditions compared to Pacific herring in Puget Sound proper.3

Although the BRT determined that Cherry Point Pacific herring represent a discrete 

population, there was no support on the BRT for Cherry Point Pacific herring to be considered 

significant to the taxon as a whole, as defined in the joint USFWS-NMFS DPS policy. The 

previous Pacific herring BRT discussed the significance of the Cherry Point Pacific herring stock 

with respect to the taxon to which it belongs (i.e., the whole biological species, Clupea pallasii) 

and came to a similar finding as reported in the previous status review (Stout et al. 2001a). 

In accordance with the joint USFWS-NMFS DPS policy (USFWS-NMFS 1996), 

considerations that can be used to determine a discrete population’s significance to the taxon as a 

whole include 1) persistence of the population segment in an ecological setting unusual or unique 

12
for the taxon, 2) evidence that loss of the population segment would result in a significant gap in 

the range of the taxon, 3) evidence that the population segment represents the only surviving 

natural occurrence of a taxon that may be more abundant elsewhere as an introduced population 

outside its historic range, and 4) evidence that the population segment differs markedly from

other populations of the species in its genetic characteristics. In reference to the first 

consideration above, the BRT noted that Pacific herring are widely distributed across the North 

Pacific Rim and have a very large number of stocks distributed evenly throughout their extensive 

range. The BRT also recognized the occurrence of other Pacific herring stocks with exceptional 

spawn timing for their local region, and that other Pacific herring stocks also spawn on fairly 

exposed coastlines as evidenced by a history of being periodically exposed to high wave energy 

and storms (see following subsection). Neither the second nor the third significance 

considerations apply to the Cherry Point Pacific herring population, as loss of this population 

would not result in a significant gap in the range of Pacific herring and it does not represent the 

only surviving natural occurrence of Pacific herring. Finally, the BRT concluded that the low 

level of genetic differentiation between the Cherry Point population and other herring 

populations indicated some degree of demographic isolation, but was not sufficiently great to 

indicate that the Cherry Point population differed “markedly” from other herring populations in 

its genetic characteristics. In particular, the BRT noted that the overall pattern of genetic 

variation within Pacific herring indicated a high level of gene flow among populations. Detailed 

evidence supporting the BRT’s conclusions on discreteness and significance are presented in the 

following subsection. 

Evidence Supporting Discreteness and Significance Decisions 

Distribution of Pacific Herring 

Pacific herring in the Eastern Pacific Ocean range from northern Baja California north to 

at least the Mackenzie Delta in the Beaufort Sea. Pacific herring are also found in the Russian 

Arctic from the Chukchi Sea in the east to the White Sea in the west, although the boundary 

between Atlantic and Pacific herring is unclear in this region (Hay et al. 2001b). In the 

Northwestern Pacific they are found throughout the western Bering Sea, the east coast of 

Kamchatka, and the Sea of Okhotsk; on the east and west coasts of Hokkaido, Japan; and south 

and west to the Yellow Sea off the Korean Peninsula (Haegele and Schweigert 1985, Hay et al. 

2001b). Haegele and Schweigert (1985) and the previous status review (Stout et al. 2001a) 

reviewed the extensive distribution of Pacific herring spawning grounds in California, Oregon, 

Washington, British Columbia, and Alaska. Over this range there are a large number of Pacific 

herring stocks or metapopulations and numerous occurrences of other more diverse localized 

populations. 

Number of Identified Stocks of Pacific herring

Most recent investigators recognize Atlantic and Pacific herring as separate species, 

Clupea harengus and C. pallasii, respectively (Whitehead 1985). However, much of the earlier 

literature indicated that differences between Atlantic and Pacific herring were representative of 

only a subspecific separation, as C. h. harengus (Atlantic herring) and C. h. pallasii (Pacific 

herring). 

13
Hay et al. (2001b) inventoried worldwide Atlantic and Pacific herring stocks and 

identified major Pacific herring stocks in the Eastern Pacific, western North Pacific, and 

southwestern North Pacific. In the Eastern Pacific, more than 20 populations or stocks of Pacific 

herring are recognized, normally with biomass estimates of less than 100,000 metric tons each, 

particularly in California, British Columbia, southeast Alaska, central Alaska, and western 

Alaska (eastern Bering Sea) (Hay et al. 2001b). Each of these populations or stocks is comprised 

of Pacific herring that spawn at numerous locations. Many smaller local populations are also 

recognized from California to central Alaska. Pacific herring in the eastern Bering Sea differ 

from other Pacific herring in the Eastern Pacific; they migrate longer distances, live to older 

ages, and obtain almost twice the body size of Pacific herring that occur in the Gulf of Alaska 

and further south (Hay et al. 2001b). 

In the northwestern Pacific, three different life history forms of Pacific herring are 

recognized: 1) a long-lived, migratory sea Pacific herring; 2) a coastal form that undergoes little 

or no migration; and 3) a lagoon Pacific herring that is associated throughout its life with lowsalinity estuarine areas (Hay et al. 2001b). In Russian waters of the western North Pacific, major 

Pacific herring stocks include Korf-Karagin Pacific herring, Gizhiga-Kamchatka Pacific herring, 

Okhotsk Pacific herring, Dekastri Pacific herring, and Peter the Great Bay Pacific herring (Hay 

et al. 2001b). Historically, Hokkaido-Sakhalin Pacific herring spawned along southeastern 

Sakhalin and northwestern Hokkaido. Small local populations have also been recognized in this 

region. Another major stock of Pacific herring is recognized in the Yellow Sea (Hay et al. 

2001b). Numerous herring populations occur in the coastal seas of the Arctic Ocean, including 

the Beaufort Sea off northern Alaska and Yukon and the Northwest Territories, although their 

taxonomic affinity to Pacific herring is uncertain (Hay et al. 2001b). 

Persistence and Spawn Timing 

Hay and McCarter (1997) emphasized the fact that “the continued occupation of an area 

is a fundamental consideration of any definition of stock” (Hay and McCarter 1997, p. 172). The 

same can certainly be said for a distinct population segment. Although Pacific herring have 

supported Native American fisheries in Washington State for millennia prior to Euro-American 

contact and statewide Pacific herring landing records begin in 1889 (Chapman et al. 1941), the 

first site-specific fishery landings report for Cherry Point (reported as Birch Bay) begins in 1935 

when approximately 41 short tons were landed (Williams 1959, WDF 1969) (see Figures 1–3 for 

locations mentioned in the text). 

14
Figure 1. Regional water masses of Puget Sound and geographical locations mentioned in the text. See 

Figure 2 for detail of the inset area. 

15
Figure 2. Geographical location of Cherry Point and other localities mentioned in the text. 

16
Figure 3. Geographical locations in the Strait of Georgia and on the southern coast of British Columbia 

mentioned in the text. 

17
The first historical reference to Pacific herring spawning during April to June in the 

vicinity of Cherry Point (then defined as Birch Point and Hales Pass)4 was found in a short 

article in the February 1916 issue of the popular publication Pacific Fisherman. This article 

describes the establishment of Washington State herring reserves where harvest was prohibited 

during the time of spawning (Pacific Fisherman 1916, p. 21) and stated that: 

Several herring reserves on Puget Sound were set aside on Jan. 19 by Fish 

Commissioner Darwin and the closed season of each announced as follows: 

Port Hadlock, Jan. 1 to Feb. 15; Hales pass, April 1 to June 15; Jackson cove, Feb. 

15 to March 31; Birch point, April 1 to June 15; Holmes harbor, Feb. 15 to March 

31. 

The establishment of Pacific herring reserves at Birch Point and Hales Pass (Hale 

Passage, Whatcom County) from 1 April to 15 June, while other areas of Puget Sound were set 

aside from January to March, indicates that late-spring spawning Pacific herring have been 

recognized in the vicinity of Cherry Point for at least 90 years. Although not definitive as to 

spawn timing, the June 1905 issue of Pacific Fisherman refers to Pacific herring being caught in 

large numbers in Hale’s Pass (Hale Passage, Whatcom County) at Lummi Island during the “past 

month” (Pacific Fisherman 1905a, p. 17) and to Pacific herring entering salmon traps at Birch 

Bay (Pacific Fisherman 1905b). These records, if accurate as to timing, would extend the 

historical record for Cherry Point late-spring spawning Pacific herring to almost 100 years. 

Spawning at all other Pacific herring locations in Puget Sound, Hood Canal, and the Strait of 

Juan de Fuca currently occurs from late January through early April (Trumble 1983, Lemberg 

et al. 1997, O’Toole et al. 2000) with peak spawning starting the last week of February or the 

first week of March (Table 1) (O’Toole et al. 2000). Spawning at Cherry Point begins in early 

April and ends in early June with peak spawning activity around 10 May (Table 1) (O’Toole 

et al. 2000). 

Currently, five Pacific herring management regions are recognized by Department of 

Fisheries and Oceans Canada (DFO) in British Columbia: 1) Queen Charlotte Islands, 2) North 

Coast (Prince Rupert District), 3) Central Coast, 4) Strait of Georgia, and 5) West Coast 

Vancouver Island. Johnstone Strait is not considered a management region at this time, although 

it was in the past. Each of these regions is further divided into Statistical Areas, which are 

further divided into sections, which are named and numbered (Hay and McCarter 2004a). The 

boundaries of each of the 108 Pacific herring sections are illustrated by region in Figure 4. In 

general, Pacific herring spawn from January to May in southern British Columbia and from midJanuary to June in northern British Columbia (Taylor 1964, Hourston 1980). Spawn timing by 

herring section in each region is illustrated in Figures 5–9. 

4 There are two locations in Washington inshore waters currently named Hale Passage; one in south Puget Sound 

separating Fox Island and the Kitsap Peninsula (Pierce County), and the other in the southern Strait of Georgia 

separating Lummi Island and the mainland (Whatcom County). Many early references referred to Hale Passage in 

Whatcom County as Hale Pass, Hales Pass, or Hales Passage. When confusion could occur as to which Hale 

Passage is being referred to, we identify the location by parenthetical reference to the location’s county. 

18
Table 1. Range (gray shading) and peak (black shading) of documented spawn timing for WDFW Puget Sound Pacific her

from Lemberg et al. (1997), O’Toole et al. (2000), and WDFW.* 

Puget Sound herring stock (abbr.) January February March April May 

Squaxin Pass (SP) Wollochet Bay (WB) Quartermaster Harbor (QM) Port Orchard / Port Madison (PO) South Hood Canal (SH) Quilcene Bay (QB) Port Gamble (PG) Kilisut Harbor (KH) Port Susan (PS) Holmes Harbor (HH) Skagit Bay (SB) Fidalgo Bay (FB) Samish Bay / Portage Bay (SPB) Interior San Juan Islands (ISJ) Northwest San Juan Islands (NSJ) Semiahmoo Bay (SAB) Cherry Point (CHPT)Discovery Bay (DIB) Dungeness Bay (DB) * K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., 30 Nov. 2004. 

19
Figure 4. DFO Pacific herring sections in the six regions of British Columbia. Maps modified from those available at http

.dfo-mpo.gc.ca/sci/herring/bulletin_e.htm (DFO 2004). 

20
Figure 5. Pacific herring spawn timing observations (Julian Calendar day of the year corrected for leap years) by DFO herr

British Columbia Strait of Georgia herring management region from 1928 to 2004. Length of each box shows the 

central 50% of the values fall, and the center line in each box marks the median of the sample. Circles represent farepresent outside values. Horizontal line indicates the 120th day of the year (approximately 1 May). See Figure 4 f

location of sections. Data from http://www-sci.pac.dfo-mpo.gc.ca/herspawn/default.htm (DFO 2004). 

21
Figure 6. Pacific herring spawn timing observations (Julian Calendar day of the year corrected for leap years) by DFO herr

British Columbia Johnstone Strait herring management region from 1928 to 2004. Length of each box shows the rcentral 50% of the values fall, and the center line in each box marks the median of the sample. Circles represent farepresent outside values. Horizontal line indicates the 120th day of the year (approximately 1 May). See Figure 4 f

location of sections. Data from http://www-sci.pac.dfo-mpo.gc.ca/herspawn/default.htm (DFO 2004). 

22
Figure 7. Pacific herring spawn timing observations (Julian Calendar day of the year corrected for leap years) by DFO herr

British Columbia West Coast Vancouver Island herring management region from 1928 to 2004. Length of each bowithin which the central 50% of the values fall, and the center line in each box marks the median of the sample. Coutside values and Xs represent outside values. Horizontal line indicates the 120th day of the year (approximately 

for geographical location of sections. Data from http://www-sci.pac.dfo-mpo.gc.ca/herspawn/default.htm (DFO 20

23
Figure 8. Pacific herring spawn timing observations (Julian Calendar day of the year corrected for leap years) by DFO herr

British Columbia Central Coast herring management region from 1928 to 2004. Length of each box shows the rancentral 50% of the values fall, and the center line in each box marks the median of the sample. Circles represent farepresent outside values. Horizontal line indicates the 120th day of the year (approximately 1 May). See Figure 4 f

location of sections. Data from http://www-sci.pac.dfo-mpo.gc.ca/herspawn/default.htm (DFO 2004). 

24
Figure 9. Pacific herring spawn timing observations (Julian Calendar day of the year corrected for leap years) by DFO herr

British Columbia Queen Charlotte Islands (Sections 1–25) and North Coast (Sections 32–53) herring management 2004. Length of each box shows the range within which the central 50% of the values fall, and the center line in ea

median of the sample. Circles represent far outside values and Xs represent outside values. Horizontal line indicat

year (approximately 1 May). See Figure 4 for geographical location of sections. Data from http://www-sci.pac. dfherspawn/default.htm (DFO 2004). 

25
Chapman et al. (1941) referred to an unpublished report of observations of Pacific herring 

spawning grounds in Puget Sound made in 1927 by Arthur S. Einarsen of the Washington 

Department of Fisheries. According to Chapman et al. (1941), the Einarsen report listed the 

spawn timing of the Birch Bay (Cherry Point) population as occurring from 1 May to 10 June in 

1927. Chapman et al. (1941) does not indicate whether Einarsen recorded spring spawning 

Pacific herring at Hale Passage (Whatcom County), Point Roberts, or from Point Whitehorn 

south to Lummi Bay (Figure 2). 

Although he does not address the specific spawn timing of different Pacific herring 

locations, Einarsen in another report (1928) in reference to the Puget Sound herring fishery 

stated that “the bulk are taken at Hales Pass [Hale Passage, Whatcom County], Holmes Harbor, 

Birch Bay, Poulsbo, and Discovery Bay” and that “all these areas are spawning beds” (1928, 

p. 132). Einarsen further noted that “herring are available here [in Puget Sound] in one district 

or another from October 15th to June 25th of each year” (1928, p. 133). 

Chapman et al. (1941) recorded spawning in Birch Bay from 26 April to 22 May in 1936 

and on 20 and 22 April in 1937. Chapman et al. (1941) reported that the spring run in Hales Pass 

(Hale Passage, Whatcom County) spawned on 20 April and from 5 to 10 May 1936. Chapman 

et al. (1941) indicated that two distinct runs occurred in the vicinity of Hales Pass (Hale Passage, 

Whatcom County), a winter run spawning in late February to early March (this is most likely a 

reference to Pacific herring currently defined as the Samish Bay-Portage Bay stock) and the 

spring run, spawning “in the latter part of April and in May” (Chapman et al. 1941, p. 10). 

Chapman et al. (1941) made no mention of Pacific herring spawning at Point Roberts or from

Point Whitehorn south to Lummi Bay. Katz (1942, p. 28) also records time of spawning for 

Pacific herring at Birch Bay as “late April and early May.” 

Pasquale (1965, p. 19) reported a “light-to-medium (density) spawn deposition on eel 

grass in an area of approximately 1⁄4 mile × 2 miles on the Pt. Whitehorn side of Birch Bay” that 

occurred on about 31 May 1962. Pasquale (1965, p. 19) estimated that spawning at Birch Bay 

normally occurred from “May 19 through 31.” By the early 1970s, Meyer and Adair (1978, p. 

39) reported that spring spawning Pacific herring in the Strait of Georgia region “utilize[d] four 

major geographical areas: Point Roberts, Birch Head, Point Whitehorn-Cherry Point, and Hale 

Passage.” 

In addition to spring-spawning Pacific herring at Birch Bay and Hales Pass (Hale 

Passage, Whatcom County), Chapman et al. (1941, p. 8) stated that “[i]n Echo Bay and Shallow 

Bay on Sucia Island there is a run of fish which in 1936 spawned in the middle of May” and “[i]n 

1936 in the last week of May, a good spawning school of herring occurred in a small bay on the 

President Channel side of Waldron Island about two miles from the northeast point” (1941, p. 9). 

Sucia Island and Waldron Island are approximately 17 and 28 km southwest of Cherry Point 

(Figure 2). Einarsen (1928) also listed Waldron Island as the location of a spawning run of 

Pacific herring, although he did not note the time of spawning. 

Both Thompson (1917) and Hay and Outram (1981) encountered an unusual group of 

large Pacific herring with anomalously reduced maturity states while conducting Pacific herring 

sampling off Point Grey, British Columbia and in the southern Gulf Islands, respectively (Figure 

3). Several lines of evidence indicate that these fish were from the Cherry Point Pacific herring 

26
population. The mixed sample of small mature (ripe) and large immature (unripe) Pacific 

herring sampled by Thompson (1917, p. S53) in September and October at Point Grey off 

Vancouver, British Columbia (Figure 3), prompted him to postulate that these were “grounds for 

believing that there are summer spawning herring” in the vicinity. However, Thompson (1917, 

p. S53) stated that “there has been no opportunity of corroborating this by actual search for 

spawning herring during any particular season, nor by an examination of Point Grey herring 

during any other time of the year.” Point Grey, British Columbia is approximately 57 km north 

of Cherry Point, Washington (Figures 2 and 3). Similarly, Hay and Outram (1981) reported 

upon Pacific herring samples taken in the vicinity of Porlier Pass (Figure 3) during 24–28 

February 1975 that consisted of mixtures of Pacific herring with different degrees of sexual 

maturity. In these samples, similar to Thompson’s (1917) samples, less mature Pacific herring 

were older and larger than the more mature Pacific herring. Hay and Outram (1981) and Hay 

and McCarter (1999) postulated that these larger immature fish were likely representative of a 

migratory stock, as differentiated from local smaller, mature Pacific herring. Both of these 

studies suggest that a population of fish with anomalous spawn timing was sampled, most likely 

representative of Cherry Point Pacific herring. 

Barraclough (1967) reported on the occurrence of larval Pacific herring in surface trawls 

on 5–8 July 1966 in the southern SOG, between the Fraser River delta and Vancouver Island. 

Based on the size of these larval Pacific herring, Barraclough (1967) calculated that they were 

the result of spawning that had occurred between 22 May and 4 June, which was considerably 

later than any previously reported Pacific herring spawn timing in the British Columbia portion 

of the Strait of Georgia (Barraclough 1967). Based on the counterclockwise flow of currents in 

the Strait of Georgia, Barraclough (1967) postulated that these larvae had hatched from spawn 

deposition in the vicinity of Boundary Bay. Outram and Haegele (1969) further reported that: 

A survey was carried out by Biological Station personnel during 1969 to 

determine the origin of exceptionally small larval herring found in plankton tows 

made in June and July in the southern portion of the Strait of Georgia. The 

shoreline from Boundary Bay (Area 29) south across the International Boundary 

Line to the San Juan Islands was searched for evidence of late, unobserved 

herring spawnings with the MV Caligus. Two medium-intensity depositions were 

located, one at Birch Bay (3.2 mi), the other at Hale Passage (0.9 mi). These 

spawnings took place on May 17 and 22, respectively, and could be the source of 

the small larval herring found in June and July plankton hauls. 

WDF (1971) listed Pacific herring spawning grounds in Puget Sound and provided a 

chart that documented numerous spawning events in April and May at Point Roberts, from

Blaine to Birch Bay, from Point Whitehorn to Sandy Point, and at Hale Passage and Portage 

Bay. Spawning in the first few days of June was also recorded between Point Whitehorn and 

Sandy Point and at Hale Passage and Portage Bay. 

In general, Pacific herring spawn from January to May in southern British Columbia and 

from mid-January to June in northern British Columbia (Taylor 1964, Hourston 1980) (Figures 

5–9). Outram and Haegele (1969) found a difference of six weeks in the mean spawn timing 

(from 8–9 March to 20–21 April) occurred between spawning areas in extreme southern and 

northern British Columbia. However, several exceptions to these generalities occur (Outram and 

27
Haegele 1969, Hay 1985, DFO 2004). For example, Pacific herring in two geographically 

adjacent spawning sections in the northern Queen Charlotte Islands, Masset Inlet (Section 011) 

and Naden Harbour (Section 012), exhibit some of the extreme latest and earliest spawn timings 

on the British Columbia coast, respectively (Figure 9) (Haegele and Schweigert 1985, Hay 

1985). Masset Inlet spawnings have been documented in late-June to July with a mean spawn 

date of 20 June, while Naden Harbour spawnings occur in late-January or in early February with 

a mean spawn date of 2 March (Figure 9) (Hay 1985, 1990, Hay and McCarter 1999, Stout et al. 

2001a, their figures 13c and 21, DFO 2004). Another local population in the Queen Charlotte 

Islands Region, Skidegate Inlet (Section 022), has a mean spawn date of 14 May while Pacific 

herring in other nearby sections spawn mainly in April (Haegele and Schweigert 1985, Hay 

1985). Pacific herring in Burke Channel (Section 084), in the Central Coast Region of British 

Columbia, exhibit a mean spawn date of 1 June, which is consistently later than spawn timings 

for other Sections in the Region (Figures 8 and 9) (Scattergood et al. 1959, Haegele and 

Schweigert 1985, Hay 1985, Stout et al. 2001a, their figures 13c and 21, DFO 2004). Hay (1985, 

p. 124) noted that “even within the same general locations, such as the northern Queen Charlotte 

Islands or San Francisco Bay, the earliest and latest spawnings can be nearly 6 mo apart.” 

Sporadic past occurrence of Pacific herring spawning during May in the Canadian SOG 

has occurred in the following DFO Pacific Herring Sections: Section 142, Baynes Sound 

(particularly from 1974–1978); Section 173, Yellow Point (2 May 1955); Section 135, Cape 

Mudge (3 May 1969); Section 152, Powell River (15 May 1952); Section 293, Boundary Bay (7 

May 1975); and Section 193, Victoria Harbour (29 May 1995) (Hourston 1980, DFO 2004) 

(Figure 10 and Table 2). 

The adaptive value of spawn timing in the Pacific Northwest was articulated in the 

following quotation by Hay (1990, p. 2400): 

These extreme differences in spawning time must have evolved in the last 10,000 

yr since glacial recession. The large spawning time differences between stocks 

are evidence of local and rapid selection, and such selection indicates that 

spawning time has significant survival value. An explanation for differences in 

spawning times is that the herring have spawning times that match local 

zooplankton production schedules, particularly the time of egg production by 

copepods because copepod eggs are, overwhelmingly, the dominant food 

organism of larval herring (Wailes 1936). 

28
Figure 10. Geographic distribution of WDFW Pacific herring stocks (stock abbreviations as in Table 1) 

and herring sections in the Canadian SOG (132, Deepwater Bay; 134, Bute Inlet; 135, Cape 

Mudge; 136, Reed Island; 141, Oyster Bay; 142, Baynes Sound; 143, Qualicum; 151, Redonda 

Islands; 152, Powell River; 162, Hotham Sound; 163, Malaspina Strait; 164, Jervis Inlet; 165, 

Sechelt Inlet; 172, Nanoose Bay; 173, Yellow Point; 181, Swanson Channel; 182, Plumper 

Sound; 191-192, Saanich Peninsula; 193, Victoria Harbour; 202, Sooke Harbour; 280, Howe 

Sound; 291, Fraser River Foreshore; and 293, Boundary Bay). Unnamed sections 161 and 201 

normally receive no appreciable herring spawn. 

29 
Table 2. Herring spawn records in the Strait of Georgia with a start date equal or greater than the 120th day of the year (app

DOY, Julian calendar day of the year; ND, no data. Data from DFO.* 

Spawn length Spawn width 

Year Herring section Location name DOY (m) (m) Egg layer

1952 152-Powell River Lund 136 274 27 2.96 1955 173-Yellow Point Boat Harbour 122 274 2 2.15 1969 135-Cape Mudge Heriot Bay 123 69 4 2.96 1969 162-Hotham Sound Willingdon Beach 120 640 18 2.96 1974 142-Baynes Sound Deep Bay 132 457 91 1.34 1975 142-Baynes Sound Union Bay 132 366 23 2.96 1975 142-Baynes Sound Hindoo Creek 132 914 23 2.96 1975 293-Boundary Bay Boundary Bay 127 914 274 2.96 1976 142-Baynes Sound Gartley Pt 131 27 5 1.34 1976 142-Baynes Sound Union Bay 130 548 9 2.15 1976 142-Baynes Sound Hindoo Creek 131 91 9 1.34 1977 142-Baynes Sound Comox Bar 128 1,554 27 0.50 1977 142-Baynes Sound Union Bay 134 640 69 3.00 1978 142-Baynes Sound Willemar Bluff 148 137 137 1.00 1995 193-Victoria Harbour James Bay 149 ND 11 2.00 

* D. E. Hay, Fisheries and Oceans Canada, Biological Sciences Branch, Nanaimo, B.C., Canada. Pers. commun., December 2004

30
Spawning Location 

Haegele and Schweigert (1985, p. 41) noted that Pacific herring almost exclusively 

spawn in “inlets, sounds, bays, and estuaries that are somewhat sheltered from the surf of the 

ocean.” Selection of these areas is likely an adaptation to minimize egg loss from wave action 

that can dislodge marine vegetation upon which eggs are laid (Haegele and Schweigert 1985). 

Taylor (1955, p. 118) stated that “survival [of spawned eggs] is highest in locations partially 

protected from wave action and least in both exposed and well protected localities.” This 

suggests that a moderate amount of wave action may improve hatching success (Taylor 1971, 

Leon 1993). In many areas in British Columbia, the bulk of Pacific herring spawn is deposited 

subtidally (Hay and Miller 1982) and is relatively protected from wave action. 

The central core area of the Cherry Point Pacific herring spawning grounds is in a 

generally exposed location in close proximity to deep water (Stick 1995, O’Toole et al. 2000) 

and is “unlike other spawning grounds in Washington waters, which are typically protected, 

relatively small bays” (Stick 1995, p. 5) (Figure 2). However, historically, portions of the Cherry 

Point Pacific herring population spawned in the relatively protected waters of Hale Passage, 

Birch Bay, Drayton Harbor, and Semiahmoo Bay when abundance of the stock was much larger 

and spawning was laterally spread out both north and south of the core Cherry Point spawning 

area (Meyer and Adair 1978) (Figure 2). 

Other examples of Pacific herring spawning in exposed shoreline areas subject to 

significant wave action at the time of spawning, although atypical, are not uncommon. Other 

documented spawning locations on relatively exposed locations, subject to significant storminduced wave action, include 30 km on either side of French Creek in the Qualicum Beach area 

(Herring Section 143) (Hay and Miller 1982); Oyster Bay (Herring Section 141) (DFO 2004); 

Atrevida Reef in the Sliammon vicinity (Powell River Section 152) (Hay et al. 1989); Macoah 

Pass in West Barkley Sound (Herring Section 232) (Tester and Stevenson 1948); Bajo Point in 

the vicinity of Nootka Sound (Herring Section 252) (Hay et al. 1989) (Figure 11); and between 

Big Bay and Tugwell Point at Prince Rupert (Herring Section 042) (Hay et al. 1989, DFO 2004) 

(Figure 12), in British Columbia and at Kah Shakes-Boca de Quadra (Skud 1960, 

Blankenbeckler 1978, Blankenbeckler and Larson 1982) and Crab Bay (Leon 1993), in southeast 

Alaska. Leon (1993, p. 24) noted that “although the Crab Bay area [a Pacific herring spawning 

area on the east side of Annette Island, in Southeast Alaska] is not on the open ocean, and can be 

classified as inside waters, the southeast winds have over 10 km of fetch in which to generate 

waves, and seas can build to nearly two meters along the shore in a 30-knot wind.” 

Growth Rate and Body Size-At-Age 

Scientific literature relating to differences in growth rate and body size-at-age among 

Pacific herring was previously reviewed in Stout et al. (2001a). In general, populations of 

Pacific herring exhibit a latitudinal cline in mean size-at-age, such that Pacific herring in 

southern locations (e.g., California) exhibit small size and Pacific herring in the north (e.g., 

Bering Sea) obtain a far larger size at a similar age. The following information specifically 

relates to Cherry Point Pacific herring. 

31
Figure 11. Geographical distribution of major Pacific herring spawning locations in southern British Columbia. Map mod

(1980) with additional information from DFO (2004). Named locations refer to DFO Pacific herring section designnecessarily to geographical locations. Circled locations indicate spawn sites on relatively exposed coastline. 

32 
Figure 12. Geographic distribution of major Pacific herring spawning locations on the northern and 

north-central coast of British Columbia. Map modified from Hourston (1980) with additional 

information from DFO (2004). Named locations refer to DFO herring section designations and 

not necessarily to geographical locations. Circled locations indicate spawn sites on relatively 

exposed coastline. 

33
5 K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., October 2004. 

Katz (1942, p. 33) examined length-at-age at nine locations in Puget Sound from samples 

taken in 1937 and determined that “the Birch Bay group, which is closest to the open sea, has the 

largest fish and the most rapid rate of growth.” Trumble (1979, 1980), Gonyea and Trumble 

(1983), and O’Toole et al. (2000) described statistically significant differences in mean growth 

rate and length-at-age data for three populations of Pacific herring sampled in the mid-1970s in 

Puget Sound: 1) Case Inlet/Squaxin Pass, 2) Hale Passage (Pierce County)-Carr Inlet (South 

Sound), and 3) southern Strait of Georgia purse seine catch (Cherry Point Pacific herring). 

Trumble (1980) found that the Strait of Georgia (Cherry Point stock) Pacific herring were 

consistently longer at age than the other populations and continued to grow later in life. Herring 

from Case Inlet (Squaxin Pass stock) grew rapidly to age 3 and then growth slowed, culminating 

in a smaller size-at-age than was apparent for Pacific herring from the Strait of Georgia (Cherry 

Point) and Hale Passage (Pierce County)-Carr Inlet samples (Trumble 1980). Herring from Hale 

Passage (Pierce County)-Carr Inlet showed intermediate growth rate and size-at-age, and 

continued to grow as the fish aged (Trumble 1980). Day (1987, p. 9) concluded that “the 

exceptionally fast growth rate that characterizes the Strait of Georgia roe herring stock [Cherry 

Point] strongly suggests that the stock migrates to the open ocean after spawning.” Likewise, 

Lassuy (1989, p. 6) suggested that growth and size-at-age differences between Squaxin Pass and 

Cherry Point Pacific herring “may result because the Strait of Georgia stocks [Cherry Point] are 

migratory while the Case Inlet [Squaxin Pass] stocks are resident.” 

The greater length- and weight-at-age of adult Cherry Point Pacific herring, after age 4, 

compared to Pacific herring at two sites on West Coast Vancouver Island (WCVI) and to other 

available locations in Puget Sound and the SOG from 1990 to 2002 are illustrated in Figures 

13–29. Data for these comparisons were derived from midwater trawl samples5 or seine gear 

samples (Hamer and Schweigert 1990, 1991, 1992, 1993, 1995, 1996, Hamer and Midgley 1997, 

1999, Midgley and Hamer 1999, Midgley and Schweigert 2000, 2002a, 2002b, 2002c) obtained 

during the spawning season for each stock or Herring Section. All British Columbia data were 

from collections with a majority of the fish expressing a maturity index of four or higher. Length 

in all cases was recorded as standard length (Gonyea 1985, Hamer 1989). 

At age 3, mean length (Figures 14 and 20) and weight (Figures 22 and 28) of Cherry 

Point Pacific herring, although greater than calculated means for most sites in Washington, are 

similar to mean lengths and weights computed for Pacific herring in the Canadian SOG and off 

WCVI. Tables 3 and 4 show pairwise comparison probabilities of length and weight, 

respectively, for 19 populations at age 3, over the 1990–2002 time period. By age 3, Cherry 

Point Pacific herring were significantly different (P ≤ 0.05) in mean length from Interior San 

Juan Islands, Samish/Portage bays, Fidalgo Bay, Skagit Bay, Port Orchard-Port Madison, and 

Squaxin Pass but not from Semiahmoo Bay, Port Susan, Port Gamble, Kilisut Harbor, 

Quartermaster Harbor, and all of the Canadian Herring Sections with the exception of Baynes 

Sound, which had a significantly greater mean length (Table 3). Similarly, by age 3, Cherry 

Point Pacific herring had a significantly (P ≤ 0.05) greater mean weight from Semiahmoo Bay, 

Interior San Juan Islands, Samish/Portage bays, Fidalgo Bay, Skagit Bay, Port Orchard-Port 

Madison, and Squaxin Pass but not from Port Susan, Port Gamble, Kilisut Harbor, Quartermaster 

Harbor, and all of the Canadian Herring Sections (Table 4). 

34
Nootka Sound (252) 

West Barkley Sound (232) 

Baynes Sound (142) 

Powell River (152)

Nanoose Bay (172) 

Yellow Point (173) 

Swanson Channel (181) 

Cherry Point 

Semiahmoo Bay

Interior San Juan Islands 

Samish/Portage Bays 

Fidalgo Bay

Skagit Bay 

Port Susan 

Port Gamble

Kilisut Harbor

Port Orchard/Madison 

Quartermaster Harbor

Squaxin Pass 

Figure 13. Pacific herring sampling sites and associated graphical symbols necessary for interpretation of 

Figures 14–19 and 22–27. 

35
6 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean length (mm)

140

150

160

170

180

190

200

210

Age 3

Figure 14. Mean length-at-age for 3-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.6

36
7 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean length (mm)

150

160

170

180

190

200

210

220

Age 4

Figure 15. Mean length-at-age for 4-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.7

37
8 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mea

n lengt

h (

mm)

160

170

180

190

200

210

220

230

240

Age 5

Figure 16. Mean length-at-age for 5-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.8

38
9 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean length (mm)

140

160

180

200

220

240

260

Age 6

Figure 17. Mean length-at-age for 6-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.9

39
10 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean length (mm) 180

190

200

210

220

230

240

250

260

Age 7

Figure 18. Mean length-at-age for 7-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.10

40
11 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean length (mm)

190

200

210

220

230

240

250

260

270

Age 8

Figure 19. Mean length-at-age for 8-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.11

41
12 See footnote 5. 

Figure 20. Comparisons of adjusted least squares means and standard errors of length for age-3 Pacific 

herring over the period 1990–2002 from West Coast Vancouver Island (Sections 232 and 252),

Canadian SOG (Sections 142, 152, 172, 173, and 181), and Washington State. The interaction 

effect of population and year was not statistically significant for age 3 (P = 0.109). Data from

Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley (1997, 1999), 

Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), and 

WDFW.12

42
13 See footnote 5. 

Figure 21. Comparisons of adjusted least squares means and standard errors of length for age-6 Pacific 

herring over the period 1990–2002 from West Coast Vancouver Island (Sections 232 and 252),

Canadian SOG (Sections 142, 152, 172, 173, and 181), and Washington State. The interaction 

effect of population and year was not statistically significant for age 6 (P = 0.467). Data from

Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley (1997, 1999), 

Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), and 

WDFW.13

43
14 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean weight (g)

20

40

60

80

100

120

140

Age 3

Figure 22. Mean weight-at-age for 3-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.14

44
15 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean weight (g)

40

60

80

100

120

140

Age 4

Figure 23. Mean weight-at-age for 4-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.15

45
16 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean weight (g)

60

80

100

120

140

160

180

200

Age 5

Figure 24. Mean weight-at-age for 5-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.16

46
17 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

M

ean weight (g)

40

60

80

100

120

140

160

180

200

220

240

260

Age 6

Figure 25. Mean weight-at-age for 6-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.17

47
18 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

M

ean weight (g)

100

120

140

160

180

200

220

240

260

280

Age 7

Figure 26. Mean weight-at-age for 7-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.18

48
19 See footnote 5. 

Year

1990 1992 1994 1996 1998 2000 2002

Mean weight (g)

80

100

120

140

160

180

200

220

240

260

280

300

Age 8

Figure 27. Mean weight-at-age for 8-year-old Pacific herring spawners sampled from 1990 to 2002 on 

spawning grounds with seine or trawl gear. Sampling sites and symbols as described in Figure 

13. Data from Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley 

(1997, 1999), Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), 

and WDFW.19

49
20 See footnote 5. 

Figure 28. Comparisons of adjusted least squares means and standard errors of weight for age-3 Pacific 

herring over the period 1990–2002 from West Coast Vancouver Island (sections 232 and 252), 

Canadian SOG (Sections 142, 152, 172, 173, and 181), and Washington State. The interaction 

effect of population and year was not statistically significant for age 3 (P = 0.279). Data from

Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley (1997, 1999), 

Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), and 

WDFW.20

50
Figure 29. Comparison of adjusted least squares means and standard errors of weight for age-6 Pacific 

herring over the period 1990–2002 from West Coast Vancouver Island (Sections 232 and 252), 

Canadian SOG (Sections 142, 152, 172, 173, and 181), and Washington State. The interaction 

effect of population and year was not statistically significant for age 6 (P = 0.312). Data from 

Hamer and Schweigert (1990, 1991, 1992, 1993, 1995, 1996), Hamer and Midgley (1997, 1999), 

Midgley and Hamer (1999), Midgley and Schweigert (2000, 2002a, 2002b, 2002c), and 

WDFW.21 

21 See footnote 5. 

51
Table 3. Matrix of pairwise comparison probabilities for age-3 length data from 1990 to 2002 as illustrated in Figure 20. I

statistical significance (P ≤ 0.05) after Bonferroni adjustment. Populations are: 1) Nootka Sound, Section 252; 2) WSection 232; 3) Baynes Sound, Section 142; 4) Powell River, Section 152; 5) Nanoose Bay, Section 172; 6) Yellow 7) Swanson Channel, Section 181; 8) Cherry Point; 9) Semiahmoo Bay; 10) Interior San Juan Islands; 11) Samish/Fidalgo Bay; 13) Skagit Bay; 14) Port Susan; 15) Port Gamble; 16) Kilisut Harbor; 17) Port Orchard-Port Madison

Harbor; and 19) Squaxin Pass. 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 

1 1. 02 1.00 1.00 3 1.00 1.00 1.00 4 0.60 0.70 0.00 1.00 5 1.00 1.00 0.11 1.00 1.00 6 1.00 1.00 0.01 1.00 1.00 1.00 7 1.00 1.00 0.13 1.00 1.00 1.00 1.00 8 1.00 1.00 0.05 1.00 1.00 1.00 1.00 1.00 9 0.04 0.05 0.00 1.00 1.00 1.00 1.00 1.00 1.00 

10 0.00 0.00 0.00 1.00 0.02 0.17 0.31 0.03 1.00 1.00 

11 0.00 0.00 0.00 1.00 0.01 0.23 0.63 0.02 1.00 1.00 1.00 

12 0.00 0.00 0.00 0.62 0.00 0.00 0.00 0.00 0.02 1.00 1.00 1.00 

13 0.00 0.00 0.00 1.00 0.02 0.33 0.83 0.02 1.00 1.00 1.00 1.00 1.00 

14 1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 15 0.02 0.02 0.00 1.00 0.97 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 1.00 

16 1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 1.00 1.00 17 0.00 0.00 0.00 1.00 0.00 0.04 0.23 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

18 0.01 0.01 0.00 1.00 0.32 1.00 1.00 0.42 1.00 1.00 1.00 0.18 1.00 1.00 1.00 1.00 

19 0.00 0.00 0.00 0.08 0.00 0.00 0.00 0.00 0.00 1.00 0.59 1.00 0.44 0.00 0.00 0.00 

0

52
Table 4. Matrix of pairwise comparison probabilities for age-3 weight data from 1990 to 2002 as illustrated in Figure 28. 

statistical significance (P ≤ 0.05) after Bonferroni adjustment. Populations are: 1) Nootka Sound, Section 252; 2) WSection 232; 3) Baynes Sound, Section 142; 4) Powell River, Section 152; 5) Nanoose Bay, Section 172; 6) Yellow Swanson Channel, Section 181; 8) Cherry Point; 9) Semiahmoo Bay; 10) Interior San Juan Islands; 11) Samish/Po

Bay; 13) Skagit Bay; 14) Port Susan; 15) Port Gamble; 16) Kilisut Harbor; 17) Port Orchard-Port Madison; 18) Qu19) Squaxin Pass. 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 

1 1.00 2 1.00 1.00 3 1.00 0.91 1.00 4 0.01 0.06 0.00 1.00 5 1.00 1.00 0.01 1.00 1.00 

6 0.74 1.00 0.00 1.00 1.00 1.00 

7 1.00 1.00 0.00 1.00 1.00 1.00 1.00 

8 1.00 1.00 0.36 0.13 1.00 1.00 1.00 1.00 9 0.00 0.00 0.00 1.00 0.46 1.00 1.00 0.01 1.00 

10 0.00 0.01 0.00 1.00 0.24 1.00 1.00 0.02 1.00 1.00 11 0.00 0.00 0.00 1.00 0.09 0.98 1.00 0.00 1.00 1.00 1.00 

12 0.00 0.00 0.00 1.00 0.00 0.00 0.05 0.00 1.00 1.00 1.00 1.00 

13 0.00 0.01 0.00 1.00 0.98 1.00 1.00 0.04 1.00 1.00 1.00 1.00 1.00 

14 1.00 1.00 0.01 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 

15 0.04 0.51 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.01 1.00 1.00 1.00 

16 0.43 1.00 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.02 1.00 1.00 1.00 1.00 17 0.00 0.00 0.00 1.00 0.02 0.49 1.00 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

18 0.00 0.05 0.00 1.00 1.00 1.00 1.00 0.12 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 19 0.00 0.00 0.00 1.00 0.00 0.00 0.01 0.00 1.00 1.00 1.00 1.00 1.00 0.00 0.00 0.00 

53
However, at age 5 and after, mean length (Figures 16–19 and 21) and weight (Figures 

24–27, and 29) of Cherry Point Pacific herring were greater than calculated means for all sites in 

Washington, the Canadian SOG, and off WCVI from 1990 to 2002. Tables 5 and 6 show 

pairwise comparison probabilities of length and weight, respectively, for 14 populations at age 6 

over the 1990–2002 time period. Several populations had no fish that lived to age 6. Tables 5 

and 6 illustrate that Cherry Point Pacific herring were significantly (P ≤ 0.05) longer and heavier 

than all other stocks or herring sections included in the analysis. 

Similar analyses were attempted for readily available length and weight data from the 

five-year period between 1976 and 1980, although lack of data from Washington State stocks 

other than Cherry Point limited the comparison to Cherry Point and several British Columbia 

herring sections (Figures 30 and 31). Again, data for these comparisons were derived from 

midwater trawl samples22 or seine gear samples (Hourston 1981a) obtained during the spawn 

season for each stock or herring section. All British Columbia data were from collections with a 

majority of the fish expressing a maturity index of four or higher. Length in all cases was 

recorded as standard length (Gonyea 1985, Hamer 1989). During this time period, differences in 

mean length of Cherry Point Pacific herring were consistently greater after age 4 than in two 

WCVI herring sections and in six other SOG herring sections, although these differences were 

not always statistically significant (Figure 30). However, analysis of mean weight-at-age 

indicated that Cherry Point Pacific herring were statistically heavier than all the British 

Columbia herring sections included in the analysis from age 3 to age 8 (Figure 31). 

Annulus Patterns 

Trumble (1980, 1983) reported that Strait of Georgia (Cherry Point stock) Pacific herring 

typically had a small diameter first scale annulus compared to other Puget Sound Pacific herring 

stocks, but showed normal growth to continue after age 1. Trumble (1980, p. 108) also stated 

that Cherry Point Pacific herring could be “separated from other herring because scale quality is 

very bad in terms of clarity and reliability. False annuli are common and make age 

determination difficult.” 

Age Composition 

Pacific herring age at first maturity ranges from 2 to 5 years (Hay 1985). However, along 

the west coast of North America, populations of Pacific herring exhibit a latitudinal cline in ageat-maturity, such that Pacific herring in southern locations (e.g., California) mature at an early 

age and Pacific herring in the north (e.g., Bering Sea) mature at later ages (Hay 1985, Schweigert 

et al. 2002). Ware (1985) emphasized that age at first maturity decreases with increasing 

exploitation. In other words, Pacific herring populations typically begin spawning at an earlier 

age when under stress from fishing pressure or other forms of mortality that act on older age 

classes (Ware 1985). 

Markiewicz et al. (2001) and Landis et al. (2004) interpreted Cherry Point Pacific herring 

age composition data from the mid-1970s (Figure 32) as evidence of apparent immigration into 

22 See footnote 5. 

54
Table 5. Matrix of pairwise comparison probabilities for age-6 length data from 1990 to 2002 as illustrated in Figure 21. I

statistical significance (P ≤ 0.05) after Bonferroni adjustment. Populations are: 1) Nootka Sound, Section 252; 2) WSection 232; 3) Baynes Sound, Section 142; 4) Powell River, Section 152; 5) Nanoose Bay, Section 172; 6) Yellow Swanson Channel, Section 181; 8) Cherry Point; 9) Semiahmoo Bay; 10) Samish/Portage bays; 11) Fidalgo Bay; 1Port Orchard-Port Madison; and 14) Squaxin Pass. 

1 2 3 4 5 6 7 8 9 10 11 12 13 

1 1.00 2 1.00 1.00 3 1.00 1.00 1.00 4 0.09 0.05 0.35 1.00 5 1.00 1.00 1.00 0.58 1.00 6 1.00 1.00 1.00 1.00 1.00 1.00 7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 

9 1.00 1.00 1.00 0.04 1.00 1.00 1.00 0.01 1.00 

10 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 11 0.00 0.00 0.00 0.16 0.00 0.00 0.00 0.00 0.00 1.00 1.00 

12 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 0.00 1.00 13 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 0.00 1.00 1.00 14 0.00 0.00 0.00 1.00 0.00 0.00 0.01 0.00 0.00 1.00 1.00 0.00 0.09 1

55
Table 6. Matrix of pairwise comparison probabilities for age-6 weight data from 1990 to 2002 as illustrated in Figure 29. 

statistical significance (P ≤ 0.05) after Bonferroni adjustment. Populations are: 1) Nootka Sound, Section 252; 2) WSection 232; 3) Baynes Sound, Section 142; 4) Powell River, Section 152; 5) Nanoose Bay, Section 172; 6) Yellow Swanson Channel, Section 181; 8) Cherry Point; 9) Semiahmoo Bay; 10) Samish/Portage bays; 11) Fidalgo Bay; 1Port Orchard-Port Madison; and 14) Squaxin Pass. 

1 2 3 4 5 6 7 8 9 10 11 12 13 

1 1.00 2 1.00 1.00 3 1.00 1.00 1.00 4 0.01 0.03 0.30 1.00 

5 1.00 1.00 1.00 1.00 1.00 6 1.00 1.00 1.00 1.00 1.00 1.00 7 1.00 1.00 1.00 1.00 1.00 1.00 1.00 8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 

9 1.00 1.00 1.00 0.11 1.00 1.00 1.00 0.00 1.00 

10 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 11 0.00 0.00 0.00 1.00 0.00 0.00 0.01 0.00 0.00 1.00 1.00 

12 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 0.00 1.00 13 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 1.00 1.00 0.01 1.00 1.00 14 0.00 0.01 0.04 1.00 0.12 0.23 1.00 0.00 0.02 1.00 1.00 0.13 1.00 1

56
23 See footnote 5. 

Figure 30. Comparisons of adjusted least squares means and standard errors of length for Pacific herring 

over the period 1976–1980 at Cherry Point, Washington, and in British Columbia (old Section

designations) at Nootka Sound (Section 252), West Barkley Sound (Section 232), Baynes Sound 

(Section 142), Lund (Section 152), Qualicum (Section 143), French Creek (Section 144), 

Nanoose Bay (Section 172), and Other Area 18 (Section 181). The interaction effects of 

population and year were statistically insignificant (P > 0.05) for all ages. Data from Hourston 

(1981) and WDFW.23

57
24 See footnote 5. 

Figure 31. Comparisons of adjusted least squares means and standard errors of weight for Pacific herring 

over the period 1976–1980 at Cherry Point, Washington, and in British Columbia at Nootka 

Sound (Section 252), West Barkley Sound (Section 232), Baynes Sound (Section 142), Lund

(Section 152), Qualicum (Section 143), French Creek (Section 144), Nanoose Bay (Section 172), 

and Other Area 18 (Section 181). The interaction effects of population and year were statistically

insignificant (P > 0.05) for all ages. Data from Hourston (1981) and WDFW.24

58
the Cherry Point stock from other sources and as evidence that Cherry Point Pacific herring may 

be part of a larger metapopulation. In particular, Landis et al. (2004, p. 281) stated that: 

From 1973 until 1979 there was an apparent greater number of Age 3 fish than 

could be accounted for from the previous years’ numbers of Age 2 fish. Although 

the increase may be the result of sampling error, the increases were occasionally 

30–70 times the expected number. This suggests that at one time there was 

immigration into the Cherry Point Pacific herring population that corresponded to 

the periods of high population numbers. 

These conclusions are based on the assumption that age-at-maturity (or age of 

recruitment into the spawning population) has remained constant since the 1970s and that all 

age-2 Pacific herring were mature and part of the spawning population during the 1970s. 

Alternatively, it is possible that during the 1970s to the mid-1980s a large portion of the Cherry 

Point stock did not recruit into the spawning population until age 3 or perhaps age 4. Thus, a 

large percentage of the age-2 Pacific herring would not be present on the spawning grounds as 

they were still immature. The previous status review (Stout et al. 2001a, their table 12, p. 131) 

recognized the above relationship of age-2 and age-3 Pacific herring at Cherry Point and 

interpreted these data as evidence of “a reduction in the age at maturity.” A similar situation 

obtains in northern British Columbia where Pacific herring are fully recruited into the spawning 

population at age 4 and there are typically more age-4 fish than age-3 fish in the catch. This has 

generally been interpreted as evidence that a large part of the age-3 cohort is immature and has 

yet to recruit into the spawning population and has been called the “age 3 immature hypothesis” 

(Hay and McCarter 1999, p. 4). However, alternative hypotheses invoke episodic migrations of 

mature Pacific herring from southern to northern areas to explain the apparent discrepancies 

between percent-at-age data and observed age-at-maturity (Hay and McCarter 1999). These 

competing hypotheses remain unresolved. Therefore age composition data cited in Markiewicz 

et al. (2001) and Landis et al. (2004) do not necessarily provide evidence of straying into the 

Cherry Point stock from other sources. 

Parasite Incidence 

Katz (1942) stated that Pacific herring collected in Willapa Bay in 1937 were heavily 

infested with nematodes, but that similar infestations were not present in Pacific herring 

collected in Puget Sound in 1936–37. Conversely, Trumble (1980, p. 108) stated that 

“infestation of the roundworm parasite Anasakis [sic] occurs much more heavily for the sac-roe 

herring [Cherry Point stock] than for herring elsewhere in Puget Sound.” Similarly, O’Toole 

et al. (2000, p. 10) stated that “nonquantitative observations indicate body cavities of Cherry 

Point herring are normally full of the roundworm Anasakis [sic], which is uncommonly noted in 

adult herring from other areas in Puget Sound.” According to MacKenzie (1987), the definitive 

host for adult Anisakis simplex are cetaceans such as whales and porpoises, and the first 

intermediate host(s) are euphausids. Pacific herring become infected with Anisakis larvae when 

they ingest infected euphausids. The implication is that Cherry Point Pacific herring may be 

feeding in a different region of the ocean than other stocks of Puget Sound Pacific herring. 

59
Age 2 Age 3 Age 4 Age 5 Age 6 Age 7 Age 8 Ag

Percent age composition (percent numbers of fish

at age)

100% 

80% 60% 40% 20% 

0% 

1936

1937

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

Year 

Figure 32. Cherry Point Pacific herring age composition of spawners in 1936–1937 (as Birch Bay) (Chapman et al. 1941) 25 See footnote 5. 

60
Artificial Tagging 

Much of the information on tagging of Pacific herring in British Columbia, utilizing 

metallic belly tags (1936–1967) and plastic anchor tags (1979–1991), that was reviewed by Stout 

et al. (2001a) has since appeared in the peer-reviewed literature in Hay et al. (2001a). In 

addition, Hay and McKinnell (2002) revealed that during the intensive Pacific herring tagging 

efforts that occurred between 1979 and 1992 in British Columbia, it was not unusual for “two or 

more tags from a single release session ... [to be] recovered together” (Hay and McKinnell 2002, 

p. 1960). Statistical analysis of these recovery matches indicated that some adult Pacific herring 

appeared to associate in a nonrandom manner for months to years and over considerable 

distances (Hay and McKinnell 2002). 

In recent years, DFO has begun applying coded-wire tags (CWT) to Pacific herring 

captured on the spawning grounds in British Columbia. Information on releases and recoveries 

of CWT Pacific herring from this study have been published in a series of technical reports 

(Schweigert and Flostrand 2000, Flostrand and Schweigert 2002, 2003, 2004). Although tag 

release and recovery efforts have not been uniform throughout the BC coast, recovery of strays at 

large for at least one year between the five regions (Figure 4) involved in the study (Queen 

Charlotte Islands, Prince Rupert District, Central Coast, Strait of Georgia, and West Coast 

Vancouver Island) amounted to 3 in 2000, 1 in 2001, 4 in 2002, and 41 in 2003 (Flostrand and 

Schweigert 2004). During 2003, about 3% of the recovered tags that had been applied in the 

SOG between 1999 and 2002 were recovered in the WCVI Region and 2% of the recovered tags 

that had been applied in the Central Coast in 2002 were recovered in the SOG. In addition to 

regional strays, reproductive straying was evidenced by straying between areas within regions 

including over 50 in 2002 and 196 in 2003 (Flostrand and Schweigert 2003, 2004). 

Although not new since the previous status review, the following information is specific 

to tagging of Cherry Point Pacific herring. There have been two previous efforts to tag Cherry 

Point Pacific herring; a total of 797 fish were tagged with internal metal belly tags at Birch Bay 

(Figure 2) on 22 April 1938 (Hart and Tester 1938, 1939, 1940) (Figure 33) and 18,400 Pacific 

herring were tagged at Point Whitehorn (Cherry Point) during late April to early May in 1981 

and 1982 (Buchanan 1986) (Figure 34). Hart and Tester (1938) reported that fish tagged at Birch 

Bay in 1938 were obtained from a herring-weir that was used for taking herring for bait. A total 

of 4 of the 797 Cherry Point fish tagged in 1938 were recovered. One fish was “recovered by a 

fisherman cutting up bait about five weeks after tagging...off the mouth of the Fraser River” 

(Hart and Tester 1939, p. Q66). The three additional tag recoveries occurred in Pacific herring 

reduction plants where magnet detectors were installed (Hart and Tester 1939, 1940). Two of 

these tags were recovered during the 1938–1939 fishing season and the other in 1939–1940. The 

first two recoveries were described by Hart and Tester (1939, p. Q78) as 

Birch Bay (2T): Two tags were recovered. One was recovered on the east coast 

[of Vancouver Island]. The other was reported from Barkley Sound [on west 

coast Vancouver Island], but may have originated with east coast fish. 

Subsequently, the third tag recovery was described by Hart and Tester (1940, p. K52) as: 

61
Figure 33. Recovery location of four of 797 herring tagged at Birch Bay on 22 April 1938. Black dot 

indicates site of tagging and circled numbers indicate number of recoveries at that site. Data from

Hart and Tester (1938, 1939, 1940). 

Figure 34. Approximate recovery locations of eight of the over 18,000 herring tagged at Cherry Point in 

1981 and 1982. Black dot indicates site of tagging and circled numbers indicate number of 

recoveries at that site. Data from Buchanan (1986). 

62
Birch Bay (2T): One recovery was reported from east coast Vancouver Island 

fish. The reported locality of recovery is probably correct, although Queen 

Charlotte Sound is a possible source. 

It is apparent from these descriptions that the locations of belly tag recoveries were not 

exact, as fish from many different regions were processed in certain reduction plants and 

often the tags were retrieved at the end of the season in reduction plant machinery (Hay et 

al. 1999). 

Results of the 1981 and 1982 tagging efforts at Cherry Point were described by Buchanan 

(1986, p. 159) as follows: 

One tagged fish returned to the site of tagging exactly one year later. In addition, 

one fish was returned from a roe fishery in Barkley Sound, and one from offshore 

of Barkley Sound during the summer. Three were returned from the SEVI 

[southeast Vancouver Island] area from November through March in subsequent 

seasons. During the 1982 tagging, many well recovered spent fish were mixed in 

with maturing fish. Some of these spent fish got tagged. From this seasons 

tagging, two fish were returned from successive years roe fisheries in Lambert 

Channel [in the northwest SOG]. 

Buchanan (1986) also reported that three Pacific herring tagged in the southeast Vancouver 

Island region by Canadian researchers during November through March were recovered in early 

May at Cherry Point during the early 1980s (Table 7). Buchanan (1986, p. 159) stated that “it 

would appear that at least some of this late spawning U.S. stock [Cherry Point] spends some of 

the winter and spring in the channels of the Canadian Gulf Islands.” 

Otolith Chemistry 

Gao et al. (2001) analyzed oxygen and carbon isotope ratios in otoliths from spawning 

Pacific herring collected at Cherry Point in north Puget Sound and at Port Orchard and Squaxin 

Pass in south Puget Sound. Isotope ratios from nuclei of otoliths from the two southern Puget 

Table 7. British Columbia Pacific herring tag releases recovered in known Washington State location. 

Data from DFO (2004). SA, British Columbia statistical area. 

Year Area released Area recovered Tags recovered 

1979 Porlier Pass 

SA 17, Strait of Georgia 

Cherry Point, WA 1-anchor 

1980 Beaver Point 

SA 18, Strait of Georgia 

Point Whitehorn, WA 1-anchor 

1980 Toquart Bay 

SA 23, W Coast Vancouver Is 

Grays Harbor, WA 1-anchor 

1980 Leclaire Pt 

SA 24, W Coast Vancouver Is 

Cape Flattery, WA 1-anchor 

1981 Porlier Pass 

SA 17, Strait of Georgia 

Toleak Point, WA 1-anchor 

1981 Ruxton Pass 

SA 17, Strait of Georgia 

Cherry Point, WA 1-anchor 

63
26 See footnote 3. 

Sound samples were not significantly different from one another; however, Cherry Point otoliths 

were significantly different from the two southern Puget Sound samples. The Cherry Point 

isotope ratios suggested that Pacific herring from this location experience lower salinities as 

larvae and juveniles than Pacific herring from southern Puget Sound. However, Gao et al. (2001, 

p. 2117) noted that “there are some crossing samples in the database.” Their Figure 2 shows that 

isotope ratios from 3 of the 32 Cherry Point fish fell well within the range of values shown for 

the other two sites. This overlap may indicate some degree of mixing of Pacific herring between 

the two areas or that water conditions characteristic of south Puget Sound may also occur in the 

areas frequented by Cherry Point Pacific herring during early life stages. Gao et al. (2001) also 

studied isotope ratios of second summer (1999) otolith rings in these three Pacific herring stocks. 

The results indicated that most south Puget Sound Pacific herring were rearing in high salinity 

conditions and were therefore “moving to the ocean” (Gao et al. 2001, p. 2115) (migratory stock) 

and that most Cherry Point Pacific herring with otolith isotope ratios indicative of lower 

salinities “might still remain in the spawning ground” (p. 2115) (nonmigratory stock). This 

result is surprising because nonmigratory Pacific herring would be expected to be slow growing 

and previous studies (based on tagging data and the relatively high growth rate of Cherry Point 

Pacific herring) had suggested that Cherry Point Pacific herring migrate to feed in offshore 

waters. Gao et al. (2001) did not consider the possibility that the fish they termed migratory may 

have been merely feeding deeper in the water column where salinity is higher than their 

nonmigratory fish. 

Toxic Contaminants 

It has been suggested that the differential accumulation of organochlorine contaminants 

in adult Pacific herring at Cherry Point compared to other local Pacific herring populations 

(O’Neill and West 2002) could be used as a stock distinguishing characteristic.26 Different 

levels of total PCBs, DDTs, and hexachlorobenzene in Cherry Point Pacific herring were 

indicative of disparate rearing conditions compared to Pacific herring in Puget Sound proper and 

from one site in the northern SOG. These results are further discussed in the “Risk Factors” 

subsection on page 93. 

Genetic Variation 

Several genetic studies were reviewed by the BRT to assist in the determination of the 

significance of the Cherry Point Pacific herring population. Two studies, Beacham et al. (2001, 

2002) and Small et al. (2004) compared microsatellite DNA allele variation at a number of loci 

within and between populations of Pacific herring. The Small et al. (2004) report was 

subsequently published, with some modifications, in the peer-reviewed literature as Small et al. 

(2005). A third study, Bentzen (2004), compared variation in mitochondrial DNA (mtDNA) 

haplotypes among several populations of Pacific herring and one population of Atlantic herring. 

The genetic information reviewed suggested that in general Pacific herring are characterized by 

high levels of gene flow among populations across fairly large geographic areas, consistent with 

the results of extensive tagging studies (Hay et al. 2001a). Overall, the genetic analysis of 

Beacham et al. (2001, 2002) supported the metapopulation view of Pacific herring populations in 

British Columbia, at least among the large migratory stocks. Several samples, including the 

64
single sample from a single year at Cherry Point, were identified in Beacham et al. (2001, 2002) 

as being somewhat more distinct. These included samples from later (spring-summer) spawning 

Pacific herring, samples from remotely sited “resident” Pacific herring in mainland inlets, and 

samples from sites that were geographically distant from British Columbia. Although these 

“outlier” samples appeared to cluster together in the Beacham et al. (2001, 2002) analysis, it was 

unclear whether this apparent similarity was an artifact of the analysis or an indicator of past or 

present genetic exchange. 

The report by Small et al. (2004, 2005), suggests that a number of genetically discrete 

population aggregations may exist. Within Puget Sound, there was a small degree of genetic 

differentiation among sampling sites and in some cases between years within a site. Analysis of 

samples for microsatellite allele variation indicated small but significant levels of genotypic 

differentiation between Cherry Point and other sampling sites. The estimate of FST for six Puget 

Sound populations and one Strait of Georgia population was 0.003 (95% CI = 0.001–0.006), and 

samples from four consecutive years (1999–2003) from the Cherry Point population were 

differentiated in 18 of 32 pairwise comparisons (after Bonferroni corrections) from other Puget 

Sound/Strait of Georgia samples (FST ranged from ≈0.002 to ≈0.006). Based on these data, the 

BRT hypothesized that the Puget Sound Pacific herring populations, particularly in the South 

Sound and at Cherry Point, may be characterized by a degree of isolation similar to other “inlet” 

locations in British Columbia. In some cases it was possible for the BRT to hypothesize a 

mechanism for some level of demographic isolation. For example, temporal differences in 

spawning time (Cherry Point) or geographic isolation (Squaxin Pass) could result in the observed

levels of genetic distinctiveness. 

Determining the biological significance of this low level of differentiation is difficult. 

Several simple population genetic models have been developed that use estimates of FST to 

estimate biological parameters such as time of divergence or gene flow among populations. 

Assuming a large number of equal sized populations with equal rates of migration among them, 

Wright (1978) showed that the immigrant fraction of a population, m, could be estimated by the 

relationship m = (1/4Ne)(1/FST – 1). Alternatively, assuming that a pair of populations diverged 

from a common ancestor t generations ago and have not subsequently exchanged migrants, the 

divergence time, t, can be estimated from the relationship FST = 1 – (1-1/2Ne)

t

 (Weir 1996). Both 

models make many additional assumptions, such as discrete generations and selective neutrality 

of the loci used to estimate FST. In addition, particularly when estimates of FST are very small, 

results can be sensitive to problems such as nonrandom sampling of populations (Waples 1998). 

Under both models, the effective size of the population (Ne) is critical to the interpretation of the 

results. In particular, if Ne is small, FST increases relatively rapidly among isolated populations. 

Conversely, if Ne is relatively large, FST increases very slowly over time even if populations are 

completely isolated. For example, the value of FST estimated by Small et al. (2004, 2005) of 

0.003 among herring populations in Puget Sound/Strait of Georgia is consistent with a 

divergence time of only ≈6 generations if Ne is ≈1,000, but is consistent with a divergence time

of ≈600 generations if Ne is ≈100,000. A similar situation occurs when estimating immigration 

fraction; the same estimate of FST could imply either a large or small immigration fraction 

depending on the value of Ne. Clearly, without an estimate of Ne, it is hard to determine if an 

observed level of genetic differentiation is evolutionarily significant. 

65
Herring populations, including Cherry Point, typically have spawning population sizes in 

the millions (Stout et al. 2001a), so it may be reasonable to expect that Ne could be relatively 

large. However, marine fish often have effective population sizes that are much smaller than the 

observed number of individuals in a population (e.g., Hauser et al. 2002). Several authors have 

developed methods for estimating Ne from temporal changes in allele frequencies (Nei and 

Tajima 1981, Waples 1989, Wang 2001). We used the data reported in Small (2004, 2005) to 

estimate Ne for the Cherry Point population using both Waples’s (1989) moments method and 

Wang’s (2001) likelihood method. In both cases, the point estimates of Ne for the Cherry Point 

population were ≈1000, but the 95% confidence intervals were extremely wide (≈200 – infinity). 

Analysis of mtDNA variation by Bentzen (2004) failed to identify any significantly 

differentiated sampling sites ranging from California to the Bering Sea. In general, there was 

substantial variability in mtDNA both between samples and between years from the same

sampling site. There were a number of mtDNA haplotypes that were unique to temporal samples 

within a sampling site. Conversely, there were a number of haplotypes that were common to a 

large proportion of the sampling sites. Given the large number of rare or unique mtDNA 

haplotypes, more extensive sampling is needed to provide a more discriminative analysis of 

Puget Sound and Cherry Point Pacific herring. 

Given the observed genetic variability within and between Puget Sound sampling sites of 

Pacific herring (Beacham et al. 2001, 2002, Small et al. 2004, 2005, Bentzen 2004), the BRT 

concluded that the genetic distinctiveness observed for Cherry Point Pacific herring was not of a 

magnitude that could be characterized as evidence that Cherry Point Pacific herring “differs 

markedly from other populations of the species in its genetic characteristics” (USFWS-NMFS 

1996, p. 4725). 

Previous Marine Fish DPS Designations 

It is also useful to briefly review the size and complexity of other designated DPS’s of 

marine fish that have undergone the status review process and have thus been considered both 

discrete and significant to their respective biological species. DPSs have been designated for 

portions of the range of Pacific hake (Merluccius productus), Pacific cod (Gadus 

macrocephalus), walleye pollock (Theragra chalcogramma) (NMFS 2000), copper rockfish 

(Sebastes caurinus), quillback rockfish (S. maliger), brown rockfish (S. auriculatus) (NMFS 

2001), bocaccio (S. paucispinis) (NMFS 2002), and smalltooth sawfish (Pristis pectinata) 

(NMFS 2003). Several marine fish DPSs cover geographic areas larger than the Georgia Basin 

(e.g., Pacific cod and walleye pollock DPSs extend from Puget Sound to Southeast Alaska, two 

West Coast DPSs of the bocaccio rockfish were designated off Washington and Oregon [the 

northern DPS] and off California and Mexico [the southern DPS], and all smalltooth sawfish in 

U.S. waters were designated a separate DPS). At slightly smaller geographic scales, a Georgia 

Basin Pacific hake DPS was established as separate from coastal hake and three DPSs each of 

copper and quillback rockfish (Puget Sound Proper DPS, Northern Puget Sound DPS, and 

coastal DPS) and two of brown rockfish (Puget Sound Proper DPS and coastal DPS) were 

established. Many of these marine fish DPSs include a number of identifiable subpopulations 

with numerous isolated spawning locations and a substantial level of life history and ecological 

diversity (Gustafson et al. 2000, Stout et al. 2001b). 

66
Final DPS Determination 

To allow for uncertainty in identifying the boundaries of the DPS of Pacific herring that 

incorporates Cherry Point Pacific herring, the BRT adopted a “likelihood point” method, often 

referred to as the “FEMAT” method because it is a variation of a method used by scientific 

teams evaluating options under the Forest Plan (Forest Ecosystem Management: An Ecological, 

Economic, and Social Assessment Report of the Forest Ecosystem Management Assessment 

Team [FEMAT, http://www.or.blm.gov/ForestPlan/ NWFPTitl.htm]). This method has also 

been used in all recent status review updates for federally listed Pacific salmon and steelhead 

(Oncorhynchus mykiss) ESUs. In this approach, each BRT member distributes ten “likelihood” 

points among a number of proposed DPSs, reflecting their opinion of how likely that proposal 

correctly reflects the true DPS boundaries. Thus if a member were certain that the DPS that 

contains Cherry Point Pacific herring was Cherry Point alone, he or she could assign all 10 

points to that proposal. A member with less certainty about DPS boundaries could split the 

points among two, three, or even more DPS proposals. 

The BRT considered up to seven possible DPS configurations that might conceivably 

incorporate Cherry Point Pacific herring. Ultimately each BRT member distributed their 10 

“likelihood points” amongst these possible configurations. Other possible configurations that 

encompassed either smaller or larger geographic areas were contemplated, but were not seriously 

considered. In order to try and capture the level of uncertainty on the BRT regarding the 

decision that Cherry Point Pacific herring was a discrete population, but not significant to the 

species as a whole, two of the DPS scenarios that were considered delineated Cherry Point 

Pacific herring as a DPS. The DPSs considered in this evaluation were: 

1. Multiple DPSs for Puget Sound Pacific herring based on spawn timing. 

a) Late-spring spawning Pacific herring DPS (Cherry Point) 

b) Winter spawning Puget Sound Pacific herring DPS (all other Puget Sound 

populations) 

2. Multiple DPSs for Georgia Basin Pacific herring based on spawn timing. 

a) Late-spring spawning Pacific herring DPS (Cherry Point) 

b) Winter spawning Puget Sound Pacific herring DPS (all other Georgia 

Basin populations) 

3. Georgia Basin Pacific herring DPS (current boundaries and definition of DPS - Puget 

Sound/Strait of Georgia/ Strait of Juan de Fuca). 

4. Pacific herring DPS incorporating Puget Sound, Strait of Georgia, and West Coast 

Vancouver Island spawning locations. 

5. Puget Sound to Sitka, Alaska. 

6. Puget Sound to Aleutian Peninsula. 

7. San Diego to Sitka, Alaska. 

There was very little support on the BRT for a separate Cherry Point DPS; less than 8% 

of the likelihood points were distributed amongst DPS scenarios 1 and 2. All remaining 

67
likelihoods points were distributed among scenarios supporting a DPS at the level of the Georgia 

Basin (a combination of Puget Sound and the Strait of Georgia) or greater. A majority of the 

BRT likelihood points supported retention of the current Georgia Basin Pacific herring DPS 

(scenario 3); however, over a third of the total likelihood points were distributed among 

scenarios that represented a DPS configuration that was larger than the Georgia Basin (scenarios 

4–7). There was significant support on the BRT for a larger DPS than Georgia Basin based on 

tagging studies that indicate extensive straying at scales greater than the Georgia Basin 

(Heyamoto and Pasquale 1961, Buchanan 1986, Hay et al. 2001a); genetic studies of Grant and 

Utter (1984), Beacham et al. (2001, 2002), and Small et al. (2004) that indicate wide genetic 

homogeneity of the overwhelming number of Pacific herring populations in the Pacific 

Northwest and British Columbia; and evidence that most Pacific herring populations in British 

Columbia can be described as a metapopulation (Ware et al. 2000, Ware and Schweigert 2001, 

2002, Ware and Tovey 2004). However, the BRT did not feel that these were reasons enough to 

modify the boundaries of the present DPS. The BRT noted that the ecological discreteness of the 

Georgia Basin (the inshore waters of Puget Sound and the Strait of Georgia) and concordance of 

age composition of Pacific herring among SOG and Puget Sound locations provided support for 

this decision. As currently defined, the Georgia Basin Pacific herring DPS (scenario 3) 

encompasses spawning locations of Pacific herring in all the marine waters of Puget Sound, the 

Strait of Georgia, and eastern Juan de Fuca Strait in both the U.S. and Canada (Figure 35). 

Figure 35. Generalized geographical boundary of the Georgia Basin Pacific herring distinct population 

segment. 

68
Approaches to Evaluating Risk of Extinction 

The “Extinction Risk” Question 

After the composition of an ESA species is determined, the next question to address is, 

“Is the ‘species’ threatened or endangered?” The ESA (section 3) defines the term “endangered 

species” as “any species which is in danger of extinction throughout all or a significant portion of 

its range.” The term “threatened species” is defined as “any species which is likely to become an 

endangered species within the foreseeable future throughout all or a significant portion of its 

range.” Neither NMFS nor the USFWS have developed any formal policy guidance about how 

to interpret the definitions of threatened or endangered species in the ESA. 

A variety of information is considered in evaluating the level of risk faced by a DPS.

According to the ESA, the determination of whether a species is threatened or endangered should 

be made on the basis of the best scientific information available regarding its current status, after 

taking into consideration conservation measures that are proposed or are in place. During the 

biological status review process, the BRT does not evaluate likely or possible effects of 

conservation measures except to the extent they are reflected in metrics of population or DPS 

viability; these measures are taken into account in a separate process by the NMFS regional 

offices prior to making any listing determinations. Therefore, the BRT does not make 

recommendations as to whether identified DPSs should be listed as threatened or endangered 

species, because that determination requires evaluation of factors not considered by the team. 

Rather, the BRT draws scientific conclusions about the risk of extinction faced by identified 

DPSs under the assumption that present conditions will continue into the future (recognizing, of 

course, that existing trends in factors affecting populations and natural demographic and 

environmental variability are inherent features of “present conditions”). 

Factors for Decline 

According to Section 4 of the ESA, the Secretary (of Commerce or the Interior) shall 

determine whether a species is threatened or endangered as a result of any (or a combination) of 

the following factors: destruction or modification of habitat, overutilization, disease or predation, 

inadequacy of existing regulatory mechanisms, or other natural or man-made factors. 

Collectively, these are often referred to as “factors for decline.” In the previous status review, 

the BRT did not attempt a rigorous analysis of this subject, and the same is true for this report. 

There are several reasons for this. 

1. The BRT chose to focus primarily on the question of whether a DPS is at risk rather than 

how it came to be at risk. Although the latter question is important, a population or DPS 

that has been reduced to low abundance will continue to be at risk for demographic and 

genetic reasons until it reaches a larger size, regardless of the reasons for its initial 

69
decline. Furthermore, in some cases, a factor that was important in causing the original

declines may no longer be an impediment to recovery. 

2. Unlike many ESA-listed species that face a single primary threat, Pacific herring (like

Pacific salmon) face numerous potential threats throughout every stage of their life cycle. 

It is therefore relatively easy to simply list current and past potential threats to Pacific 

herring populations, but it is much more difficult to evaluate the relative importance of a 

wide range of interacting factors. 

3. Evaluating the degree to which historic factors for decline will continue to pose a threat 

in the future generally requires consideration of issues that are more in the realm of social 

science than biological science—such as whether proposed changes will be funded, and, 

if funded, will be implemented effectively. 

Although this report does not consider factors for decline in a comprehensive way, the BRT did 

consider major risk factors that were identified in the previous status review and in the petition. 

Previous Cherry Point Pacific Herring Risk Assessments 

Previous formal risk assessments of Cherry Point Pacific herring include 1) the Cherry 

Point Screening Level Ecological Risk Assessment (EVS 1999), 2) the previous Pacific herring 

status review (Stout et al. 2001a), 3) the Regional Risk Assessment for the Cherry Point Herring 

Stock (Landis et al. 2000), and 4) Cherry Point Herring Regional Risk Assessment Phase II 

(Markiewicz et al. 2001). Aspects of the latter two studies have appeared in the peer-reviewed 

literature as Landis et al. (2004) and Hart Hayes and Landis (2004). 

Results of the Environmental Consultants, Inc. (EVS) (1999, p. ES–4) analyses were that: 

The available data indicate that trends in the Cherry Point stock are likely due 

primarily, but not necessarily entirely, to increased mortality of adults. This 

increased mortality may be due to one or more of the following: changes in ocean 

conditions, particularly sea surface temperature, that appear to have led to 

increased predation by Pacific hake off southern Vancouver Island; changes in 

competition or food supply, also associated with trends in ocean conditions; and 

increased local predation on spawning adults by seals or other species. 

The previous status review of Pacific herring concluded that “a combination of reduced 

recruitment of three-year-old herring and increased nonfishery related losses of older fish 

appeared to be the primary causes of the decline in biomass of [the] Cherry Point” population 

(Stout et al. 2001a, p. 143). Although the previous status review (Stout et al. 2001a) concluded 

that the Georgia Basin Pacific herring DPS was neither at risk of extinction nor likely to become

so, the Cherry Point stock was noted to have declined to such an extent that it may meet the 

International Union for Conservation of Nature and Natural Resources (IUCN) criteria to be 

considered “vulnerable” (Stout et al. 2001a, p. 145) and by this definition was “considered to be 

facing a high risk of extinction in the wild” (IUCN 2001, p. 9). In addition, a quantitative 

analysis of trends in abundance at Cherry Point indicated that “there is greater than 50% chance 

that the Cherry Point population will decline to one ton or less in 100 years” (Stout et al. 2001a, 

p. 131) and that “a one ton population of herring would be sufficiently small to be considered 

70
In the previous Pacific herring status review (Stout et al. 2001a) risk assessment was 

approached from several different directions. First, risk factors to Pacific herring as outlined in 

West (1997) were discussed in a qualitative manner without attempting to make a quantitative 

assessment of these factors. Second, the method used in early stages of the Pacific salmon and 

steelhead BRT process was adopted. Details of this risk approach are described in Wainwright 

and Kope (1999). Basically this is a risk matrix approach that includes information on 

abundance, population trends, productivity and variability, genetic integrity, and habitat 

condition/capacity. The risk matrix provides a way to organize and summarize the professional 

judgment of a panel of knowledgeable scientists. The third approach utilized criteria that define 

risk as presented in Musick (1999). These criteria are based on productivity measures such as 

intrinsic rates of increase, age-at-maturity, and maximum age. These criteria are similar to those 

examined in Wainwright and Kope (1999); however, they are organized somewhat differently. 

The criteria are rarity, small range and endemics, specialized habitat requirements and population 

decline. Decline thresholds are based on population resilience of the species. This method 

provided another way to examine and organize available information for the evaluation of risk 

and an opportunity to compare the results of the methods. 

Risk Assessment Methods 

Trends in Abundance

Short-term and long-term trends were calculated from time series of estimated adult 

Pacific herring spawning biomass, transformed to metric tons where appropriate. Short-term

trends were calculated using data from 1990 to the most recent year, with a minimum of 10 data 

very close to extinction and difficult to detect” (Stout et al. 2001a, p.129). On the other hand, 

Landis et al. (2000, their executive summary) concluded that 

over-harvesting coupled with a decline in the rate of recruitment of mature herring 

were responsible for the current low population levels. ... The region with the 

highest potential risk encompasses south Birch Bay, Point Whitehorn and Cherry 

Point. ... The potential risks to this area are very high due to construction and 

installation of new piers, inputs from industrial facilities, and other shoreline 

developments in the nearby vicinity. 

The second phase of the Cherry Point Herring Regional Risk Assessment (Markiewicz 

et al. 2001) concluded “that climate change with concurrent changes in sea surface temperatures, 

exploitation, and habitat loss are still important risk factors to Cherry Point herring; similar to 

results of the original assessment” (Markiewicz et al. 2001, their executive summary, p. 1). In 

addition, Markiewicz et al. (2001, their executive summary, p. 1) stated that: 

Contaminants also received a high risk score, especially after taking into 

consideration the potential risk of exposure to contaminants while the herring are 

at feeding sites outside of the Cherry Point region. The lack of data, however, 

increases the uncertainty of the risk prediction and results in an overall lower 

score for contaminants as a major risk factor to herring. 

Previous BRT Risk Assessment Methods 

71
points in the 13-year span. Long-term trends were calculated using all data in a time series since 

1973, the first year that data for U.S. portions of the DPS were available. 

Trend was calculated as the slope of the regression of the biomass of spawners (natural 

log-transformed) over the time series; to mediate for zero values, one was added to natural 

spawners before transforming the data. Trend was reported in the original units as exponentiated 

slope, such that a value greater than 1 indicates a population trending upward, and a value less 

than 1 indicates a population trending downward. The regression was calculated as 

N + = β + β X + ε 0 1 ln( 1) , (1) 

where N is the spawner biomass, β0 is the intercept, β1 is the slope of the equation, and ε is the 

random error term. 

Confidence intervals (95%) for the slope, in their original units of abundance, were 

calculated as 

exp(ln( ) ) exp(ln( ) ) 1 1 1 0.05(2),df b 1 1 0.05(2),df b b − t s ≤ β ≤ b + t s , (2) 

where b1 is the estimate of the true slope β1, t0.05(2), df is the two-sided t-value for a confidence 

level of 0.95, df is equal to n–2, n is the number of data points in the time series, and sb1 is the 

standard error of the estimate of the slope, b1. 

Population Growth Rates and Parameters 

In addition to analyses of trends in spawners, we estimated the annual long-term

population growth rate, lambda (λ), of spawners as a measure for comparative risk analysis. 

Lambda more accurately estimates the long-term trend of a population than simple regression, as 

it incorporates sources of variation such as overlapping generations. An estimate of long-term

population growth rate is important in viability assessment, as most population extinctions are 

the result of steady long-term declines (i.e., λ < 1). Methods of estimating lambda have been 

developed for data sets with high sampling error and age-structure cycles (Holmes 2001). These 

methods have been extensively tested using simulations for both threatened and endangered 

populations as well as for stocks widely believed to be at low risk (Holmes 2004), and cross 

validated with time series data (Holmes and Fagan 2002). 

Time series of herring biomass were used to estimate population growth rates and risks 

by fitting a stochastic exponential decline model with observation errors to the data, also known 

as “the corrupted diffusion model” (Holmes 2004): 

Nt+1 = Nt exp(μ + ε) (3a) 

where ε is distributed Normal(0, σ

2

), 

Ot = Nt exp(ε) (3b) 

72
where ε is distributed Normal (mean = 0,e

2

), and Nt are true population counts and Ot are yearly 

censuses. The σ

2

 variance represents the variance of long-term population trajectories and 

affected both mainly by the environmentally-driven variability in year-to-year growth rates and 

the temporal correlation in those rates. The e

2

 term represents variability due to lognormal 

measurement error and also short-term variability due to a variety of internal factors, for example 

density-dependent feedbacks, age-structure perturbations, and predator-prey feedbacks (cf 

Holmes 2001, 2004, Sabo 2005). The corrupted diffusion approximation has been shown to 

correctly describe the long-run statistical distribution of salmon populations (Holmes and Fagan 

2002, Holmes 2004) and a wide variety of other species of conservation concern (Holmes et al. 

2005). 

The parameters of the corrupted diffusion model (Equation 3) were estimated via the 

Kalman filter, a widely used algorithm for maximum likelihood estimation for state-space 

models (Lindley 2003, Holmes 2004). The metrics, λ = exp(μ) and probability of crossing a 

quasi-extinction threshold of Nt/Ncurrent = 0.05, were calculated using the parameters of the 

diffusion model as described in Dennis et al. (1991). Under this model, lambda is the median 

observed growth rate. The expectation is that half the observed time series would grow faster 

than this and half would grow slower over some observed time period t. As the time series gets 

longer (t gets big), however, the variance in the observed average growth rate goes down and 

(1/t) Nt/Ncurrent > λ. Thus lambda is also the estimate of the long-run average growth rate of the 

population. 

There is uncertainty in the estimated risk metrics given the uncertainty inherent in 

parameter estimation from finite time series. Risk metric uncertainty was expressed using 

posterior probability distributions calculated with a uniform prior on all parameters. The area 

within one area under the posterior probability distribution relative to another area gives the 

relative data support. Thus if the area under λ < 1 is 10 times greater than the area under λ > 1, 

the data support for a declining population (λ < 1) is 10 times greater than the data support for an 

increasing population. The prior odds on declining versus increasing were set to 1:1 (given the 

uniform prior on μ). This is a simple objective Bayesian analysis which makes a statement about 

the relative data support (area under the likelihood function) for different parameter values 

without making a judgment about whether some parameters are more plausible than others. If 

the uniform prior is considered very unreasonable, a test of the sensitivity to the prior is required. 

Adoption of Risk Procedures Utilized in Recent Salmonid Status Assessments 

The Georgia Basin Pacific herring DPS, similar to Pacific salmonid ESUs, is likely 

structured as a metapopulation—composed of multiple populations with some degree of 

interconnection, at least over ecological time periods. This makes the assessment of extinction 

risk difficult, especially since we have fairly solid evidence in the form of tagging studies that 

the Georgia Basin DPS is sharing relatively large numbers of migrants with populations outside 

the DPS. In the previous Pacific herring status review, as in the Pacific salmon status reviews 

prior to 1999, the BRT used a simple “risk matrix” for quantifying DPS-scale risks according to 

major risk factors (see discussion in Previous BRT Risk Assessment Methods subsection on page 

71 and Stout et al. 2001a). In recent status review updates for Pacific salmon and steelhead, the 

BRTs adopted a risk assessment method that has been used for Pacific salmon recovery planning 

and is outlined in the viable salmonid populations (VSP) report (McElhany et al. 2000). In this 

73
approach, risk assessment is addressed at two levels: first, the population level, then at the 

overall ESU (or DPS) level. We have modified the previous Pacific herring BRT approach to 

DPS risk assessment to incorporate VSP considerations. For the purposes of the Pacific herring 

status review we will refer to these VSP criteria as population viability criteria. 

In this approach, individual populations are assessed according to the four population 

viability criteria: abundance, growth rate/productivity, spatial structure, and diversity. The 

condition of individual populations is then summarized on the DPS level, and larger-scale issues 

are considered in evaluating the status of the DPS as a whole. These larger-scale issues include 

total number of viable populations, geographic distribution of these populations (to ensure 

inclusion of major life history types and to buffer the effects of regional catastrophes), and 

connectivity among these populations (to ensure appropriate levels of gene flow and 

recolonization potential in case of local extirpations). These considerations are detailed in 

McElhany et al. (2000). 

The revised risk matrix (Table 8) integrates the four major population viability criteria 

(abundance, productivity, spatial structure, and diversity) directly into the risk assessment 

process. After reviewing all relevant biological information for the Georgia Basin Pacific 

herring DPS, each BRT member assigns a risk score (see below) to each of the four population 

viability criteria. The scores are tallied and reviewed by the BRT before making its overall risk 

assessment. Although this process helps to integrate and quantify a large amount of diverse 

information, there is no simple way to translate the risk matrix scores directly into an assessment 

of overall risk. For example, simply averaging the values of the various risk factors would not 

be appropriate; a DPS at high risk for low abundance would be at high risk even if there were no 

other risk factors.

Scoring population viability criteria: Risks for each population viability factor are ranked 

on a scale of one (very low risk) to five (very high risk): 

1. Very Low Risk. Unlikely that this factor contributes significantly to risk of

extinction, either by itself or in combination with other factors. 

2. Low Risk. Unlikely that this factor contributes significantly to risk of extinction 

by itself, but some concern that it may, in combination with other factors. 

3. Moderate Risk. This factor contributes significantly to long-term risk of 

extinction, but does not in itself constitute a danger of extinction in the near 

future. 

4. High Risk. This factor contributes significantly to long-term risk of extinction 

and is likely to contribute to short-term risk of extinction in the foreseeable future. 

5. Very High Risk. This factor by itself indicates danger of extinction in the near 

future. 

Recent events: The “recent events” category considers events that have predictable 

consequences for DPS status in the future but have occurred too recently to be reflected in the 

population data. Examples include a climatic regime shift or El Niño event that may be 

anticipated to result in increased or decreased predation in subsequent years. This category is 

scored as follows: 

74
++ expect a strong improvement in status of the ESU, 

+ expect some improvement in status, 

0 neutral effect on status, 

- expect some decline in status, and 

-- expect strong decline in status. 

75
Table 8. Template for the risk matrix used in BRT deliberations. The matrix is divided into five sections 

that correspond to the four VSP “parameters” (McElhany et al. 2000) plus a “recent events” 

category.

Risk Category Score* 

Abundance

Comments: 

Growth Rate/Productivity

Comments: 

Spatial Structure and Connectivity

Comments: 

Diversity

Comments: 

Recent Events

* Rate overall risk of DPS on 5-point scale (1–very low risk, 2–low risk, 3–moderate risk, 4–increasing risk, 5–high

risk), except recent events double plus (++, strong benefit) to double minus (--, strong detriment). 

76
IUCN Criteria and Classification 

The World Conservation Union (IUCN) published Red List categories and criteria for 

classifying species that are at high risk of extinction (IUCN 2001). These criteria can be applied 

to species or to lower taxonomic levels, such as distinct population segments. There are a range 

of quantitative IUCN criteria for placing a species in the relevant IUCN categories of Critically 

Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), or Least Concern 

(LC), and meeting any one criterion is justification for listing at that threat level (IUCN 2001). 

The IUCN criteria fall into four main subject areas: 1) reduction in population size, 2) extent of 

geographic range, 3) population size, and 4) results of a quantitative analysis, such as a 

population viability analysis. In the current context, the reduction in population size criteria are 

most relevant to the available data for the Georgia Basin Pacific herring DPS. These criteria 

state that a species may be classified as Critically Endangered, Endangered, or Vulnerable when 

its population size has declined ≥80%, ≥50%, or ≥30%, respectively, over the last 10 years or 

three generations, whichever is longer, where the reduction or its causes may not have ceased, 

may not be understood, or may not be reversible (IUCN 2001). The Committee on the Status of 

Endangered Wildlife in Canada (COSEWIC) has been using quantitative criteria similar to the 

IUCN criteria to assess risk of extinction in marine fish (COSEWIC 2003). 

There has been controversy over using the IUCN decline criterion for some marine fish 

species, especially those still at high abundance despite large percentage declines (Matsuda et al. 

1997, Musick 1999, Mace and Hudson 1999, Powles et al. 2000, Hutchings 2000, 2001a, 2001b, 

Dulvy et al. 2003, 2004). This debate was triggered by the IUCN listing in 1996 of several 

commercially valuable, widespread, and highly fecund marine fishes (Matsuda et al. 1997). 

Musick et al. (1999, p. 7) suggested the IUCN decline criteria “grossly overestimate the 

extinction risk for many if not most marine fish species” and proposed modified American 

Fisheries Society risk criteria that “better reflect population resilience” (p. 11). Powles et al. 

(2000, p. 672) also suggested that some “marine species have characteristics which should make 

them more resilient to extinction risk: ‘opportunistic’ life history characteristics (high fecundity, 

planktonic larvae, and highly mobile adults, low age at maturity), high abundance, and wide 

distribution.” However, Hutchings (2000, 2001a, 2001b) and others (Dulvy et al. 2003, Mace 

and Hudson 1999, Hutchings and Reynolds 2004) cite empirical analyses indicating that marine 

fishes likely have similar extinction probabilities to those of nonmarine taxa. With the possible 

exception of some clupeids, which have a comparatively higher resilience to population declines, 

Hutchings and Reynolds (2004, p. 305) stated that “the decline-rate thresholds used by IUCN 

and COSEWIC to assign status are appropriate [for marine fishes], insofar as the probability of 

recovery is a reliable metric of extinction risk.” In light of these discussions we applied the 

IUCN decline criteria to those portions of the Georgia Basin Pacific herring DPS that have 

exhibited a decline in abundance during the past three fish generations. 

Risk Assessment 

Abundance and Trends 

New data acquired for this report since the previous status review (Stout et al. 2001a) 

include spawner biomass estimates through 2004 and length of coastline utilized for spawning 

for a number of Pacific herring spawning locations in Washington and herring sections in British 

77
Columbia. New analyses include recalculation of previous BRT metrics with additional years of 

data and estimates of median annual growth rate (λ). Information is first presented for Cherry 

Point Pacific herring (the petitioned unit) and then for the Georgia Basin Pacific herring DPS. 

Cherry Point Pacific herring 

As noted earlier, Einarsen (1928, p. 132) stated that “the bulk [of Pacific herring in 

Washington State] are taken at Hales Pass [Hale Passage, Cherry Point population], Holmes 

Harbor, Birch Bay [Cherry Point population], Poulsbo, and Discovery Bay.” In addition to this 

period of high abundance, evidence exists that Cherry Point Pacific herring went through a 

previous period of low abundance, similar to the present situation, in the late 1930s. Chapman 

et al. (1941, p. 3) stated that “three areas which formerly produced a great share of the catch 

(Discovery Bay, Hales Pass [Hales Passage] and Birch Bay) have scarcely enough fish left to 

support a fishery.” Although Pacific herring abundance at Cherry Point was too low to attract a 

fishery in the late 1930s, fishermen reported that Birch Bay had previously been “one of the best 

herring producers of any of the spawning localities in Puget Sound” (Chapman et al. 1941, p. 8). 

Washington State Pacific herring catch was reported intermittently from 1889 to 1920, 

annually from 1920, and by fishing locality from 1935 to date. Catch history and known stock 

biomass for Cherry Point Pacific herring are illustrated in Figure 36. Catch records for Birch 

Bay and Hale Passage were combined from 1935 to 1967, since Chapman et al. (1941, p. 10) 

noted that it was the spring run, in contrast to the February–March run, at Hale Passage that was 

the source of “the tremendous quantities of herring which were taken from Hales Pass [Hale 

Passage] in former years.” By the late 1950s, Cherry Point Pacific herring had apparently 

recovered and Williams (1959, p. 28) stated that “formerly depleted stocks, such as those 

spawning in ... Hale Passage and Birch Bay [Cherry Point population] have regained their 

productive levels after many years without exploitation.” 

Spawner biomass for Cherry Point Pacific herring (and other stocks in Washington’s 

inside waters) since 1973 are presented in Tables 9 and 10. Since the previous status review 

(Stout et al. 2001a), the Cherry Point Pacific herring population has shown an increasing 

abundance trend (Figure 36). The 2004 spawner biomass estimate of 1,734 short tons (1,573 

metric tons) (Table 9) was at its highest level since 1996. However, the estimate of total number 

of Pacific herring in the spawning population was at its second lowest level ever, just under 14 

million fish (Table 11). This apparent discrepancy can be explained by examination of Figure 

37, which illustrates that most of the apparent spawners that made up the Cherry Point 

population in 2004 consisted of 3–5-year-old fish with larger body mass; the 2-year-old fish were 

rare in the samples used for age composition determination in 2004 (see Table 11). There has 

also been an apparent temporal decline in size-at-age of Cherry Point Pacific herring (Figures 38 

and 39). This is most evident in ages 3–7 (Figures 38 and 39). A similar decline in weight-atage was also evident in SOG Pacific herring during the 1990s, but recent data have shown no 

obvious trend (Schweigert 2004). 

78
Biomass (short tons)

14000 12000 10000 

8000 6000 4000 2000 

0 

Harvest biomass Spawner biomass 

1935

1937

1939

1941

1943

1945

1947

1949

1951

1953

1955

1957

1959

1961

1963

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

Year 

Figure 36. Cherry Point herring spawning stock and fishery catch biomass (short tons). Catch records for Cherry Point pri

combination of Birch Bay and Hale Passage records. Data from Williams (1959), WDF (1969), and WDFW.27 

27 See footnote 5. 

79
Table 9. North Puget Sound herring biomass estimates (short tons). Estimates are from spawn deposition 

survey, except italic text, which indicates estimate is from acoustic trawl survey. Empty cell 

indicates no survey was done. DIB, Discovery Bay; SQB, Sequim Bay; DB, Dungeness Bay; FB, 

Fidalgo Bay; SPB, Samish-Portage Bay; ISJ, Interior San Juan Islands; NSJ, Northwest San Juan 

Islands; SAB, Semiahmoo Bay; and CHPT, Cherry Point. Data from WDFW.* 

Year DIB SQB DB FB SPB ISJ NSJ SAB CHPT 

1973 14,998 

1974 13,963 

1975 109 772 10,337 

1976 697 47 77 10 157 321 11,844 

1977 1,488 94 32 18 29 634 11,097 

1978 1,305 10 10,973 

1979 882 333 9,957 

1980 3,220 335 43 276 1,008 9,329 

1981 3,070 456 1,008 6,219 

1982 2,356 182 310 1,389 5,342 

1983 2,578 197 640 159 874 8,063 

1984 3,144 31 742 160 772 5,901 

1985 1,447 18 761 78 2,325 5,760 

1986 1,566 234 731 79 1,464 5,671 

1987 1,593 887 400 3,108 

1988 853 1,965 4,428 

1989 1,225 58 541 1,701 4,003 

1990 855 391 218 1,930 4,998 

1991 925 1,079 60 298 2,061 4,624 

1992 727 1,399 262 17 1,501 4,009 

1993 737 11 1,417 198 472 1,902 4,894 

1994 375 0 1,207 459 1,389 6,324 

1995 261 287 1,173 194 1,245 4,105 

1996 747 0 180 590 636 277 53 1,219 3,095 

1997 199 0 158 929 509 30 79 621 1,574 

1998 0 0 112 844 643 107 919 1,322 

1999 307 0 352 1,005 555 197 868 1,266 

2000 159 0 138 737 196 128 90 926 808 

2001 137 6 87 944 470 219 62 1,098 1,241 

2002 148 0 131 865 496 158 131 1,012 1,330 

2003 207 0 44 569 299 72 13 1,087 1,611 

2004 252 0 22 339 351 67 0 629 1,734 

* K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., October 2004. 

80
Table 10. South/Central Puget Sound herring biomass estimates (short tons). Estimates are from spawn 

deposition survey, except italic text, which indicates estimate is from acoustic trawl survey. 

Empty cell indicates no survey was done. SP, Squaxin Pass; WB, Wollochet Bay; QM, 

Quartermaster Harbor; PO, Port Orchard/Port Madison; SH, South Hood Canal; QB, Quilcene 

Bay; PG, Port Gamble; KH, Kilisut Harbor; PS, Port Susan; HH, Holmes Harbor; and SB, Skagit 

Bay. Data from WDFW.* 

Year SP WB QM PO SH QB PG KH PS HH SB 

1973 

1974 

1975 298 887 279 

1976 2,138 1,357 447 492 279 1,142 495 126 478 

1977 20 1,413 1,348 444 232 2,525 135 227 

1978 58 1,860 14 1,984 254 

1979 137 1,941 1,255 1,790 

1980 683 1,930 2,133 2,309 477 78 453 

1981 772 1,777 891 1,753 324 

1982 1,778 1,214 177 1,463 1,391 78 

1983 909 1,651 2,407 1,398 

1984 1,386 1,293 2,685 1,555 

1985 667 1,415 2,387 1,321 914 

1986 1,181 1,926 2,050 934 

1987 924 2,538 68 2,046 1,216 1,552 

1988 750 1,705 1,390 570 1,340 

1989 898 1,739 2,395 345 693 

1990 566 681 1,795 2,969 364 291 380 

1991 943 580 722 357 204 2,259 613 245 

1992 771 518 314 144 97 2,270 545 

1993 596 1,075 304 1,521 538 1,693 

1994 225 1,412 424 2,857 292 365 

1995 157 2,001 863 817 3,158 363 891 

1996 374 805 806 239 328 2,058 380 110 336 736 

1997 149 1,402 360 226 465 1,419 307 828 530 893 

1998 68 947 489 101 1,152 971 311 2,084 464 209 

1999 474 1,257 2,006 516 2,464 1,664 802 545 175 905 

2000 371 142 743 1,756 140 2,426 2,459 107 785 281 646 

2001 1,597 133 1,320 2,007 187 2,091 1,779 612 587 275 2,170 

2002 3,150 106 416 878 166 2,585 1,812 774 775 573 2,215 

2003 2,201 152 930 1,085 207 916 1,064 448 450 678 2,983 

2004 828 52 727 700 176 2,342 1,257 184 429 673 1,245 

* K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., October 2004. 

81
Table 11. Age and year of millions of herring in the Cherry Point population. Data from WDFW.* 

Age (years) 

Year 2 3 4 5 6 7 8 9+ Total 

1973 0.16 7.56 35.13 22.77 12.52 2.76 0.41 0.00 81.32 

1974 0.54 23.21 16.62 26.28 15.90 6.59 0.99 0.09 90.32 

1975 0.16 15.42 6.09 9.27 13.58 7.28 1.99 0.16 53.90 

1976 5.53 10.17 18.09 8.33 9.83 11.06 4.37 1.23 68.25 

1977 13.91 22.41 6.15 7.91 5.20 6.81 6.66 4.10 73.22 

1978 1.24 41.75 14.15 5.03 4.72 2.78 3.40 4.25 77.32 

1979 3.82 8.07 25.75 10.04 3.53 4.24 1.73 2.63 59.75 

1980 40.16 6.22 5.05 9.95 7.24 2.12 1.32 1.10 73.14 

1981 5.99 20.71 4.89 3.16 5.27 1.39 0.34 0.42 42.19 

1982 16.41 8.96 10.67 3.17 1.29 0.96 0.25 0.00 41.66 

1983 24.70 12.50 8.66 10.92 2.62 0.67 0.79 0.18 60.99 

1984 23.95 6.49 5.87 5.72 4.43 1.01 0.29 0.29 48.10 

1985 23.90 21.67 6.91 1.45 0.95 0.61 0.17 0.00 55.70 

1986 30.80 14.96 5.46 2.21 1.21 0.28 0.22 0.06 55.20 

1987 12.58 11.03 4.26 1.10 0.45 0.15 0.09 0.12 29.80 

1988 14.79 16.12 6.59 2.01 0.52 0.16 0.00 0.00 40.20 

1989 34.10 7.89 5.00 1.91 0.05 0.05 0.00 0.00 49.00 

1990 27.18 18.39 3.09 3.20 1.28 0.11 0.11 0.00 53.30 

1991 10.61 16.76 7.82 2.67 1.80 0.20 0.04 0.00 39.90 

1992 23.76 8.29 7.82 1.96 0.38 0.26 0.04 0.00 42.50 

1993 55.34 6.77 2.21 1.41 0.87 0.27 0.07 0.00 67.00 

1994 73.72 9.25 2.16 0.69 0.52 0.09 0.00 0.00 86.43 

1995 20.26 18.08 2.22 0.50 0.71 0.13 0.00 0.00 41.95 

1996 8.65 10.79 7.79 1.13 0.20 0.29 0.03 0.00 28.85 

1997 3.86 6.05 4.36 0.44 0.13 0.00 0.00 0.00 14.83 

1998 13.06 2.14 1.36 0.32 0.12 0.00 0.00 0.00 17.01 

1999 4.18 9.13 0.65 0.16 0.01 0.00 0.00 0.00 14.13 

2000 5.22 2.51 1.41 0.02 0.00 0.00 0.00 0.00 9.18 

2001 5.59 6.43 1.90 0.33 0.00 0.00 0.00 0.00 14.26 

2002 11.17 5.20 1.52 0.22 0.22 0.00 0.00 0.00 18.32 

2003 14.41 7.88 1.24 0.31 0.07 0.00 0.00 0.00 23.94 

2004 0.38 4.17 5.72 2.67 0.58 0.26 0.11 0.00 13.89 

* K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., October 2004. 

82
Herring abundance (millions o

f fish)

100.0 

90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 

0.0 

Age 2 Age 3 Age 4 Age 5 Age 6 Age 7 Age 8 Age 9+ 

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

Year 

Figure 37. Number of Cherry Point Pacific herring at age from 1973 to 2004. Data from K. Stick.28 28 See footnote 5. 

83
29 See footnote 5. 

Figure 38. Cherry Point Pacific herring mean length-at-age for ages 2 through 9 from 1973 to 2004. 

Linear regression lines and 95% confidence intervals are included. Data from K. Stick.29

84
30 See footnote 5. 

Figure 39. Cherry Point Pacific herring mean weight-at-age for ages 2 through 9 from 1973 to 2004. 

Linear regression lines and 95% confidence intervals are included. Data from K. Stick.30

85
31 K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., June 2004. 

Short-term (1990–2004) and long-term (1973–2004) trends in biomass of Cherry Point 

Pacific herring are illustrated in Figures 40 and 41. Both the long-term trend of 0.92 (95% CI, 

0.91–0.93) and the short term trend of 0.89 (95% CI, 0.84–0.93) (Table 12) indicate that Cherry 

Point Pacific herring have experienced severe declines in abundance over these time periods. 

Despite the slight positive increase in biomass since 2000 (Figures 36, 40, and 41), the spawner 

biomass has experienced a decline of about 87% since 1973. The current biomass estimate is at 

approximately half the level set by WDFW (Bargmann 2001) as necessary for the stock to 

maintain itself and provide harvest. The latest status classification by WDFW of the Cherry 

Point population is “Critical” (Table 13). 

The length of coastline utilized by Cherry Point Pacific herring for spawning deposition 

(spawn length) since 1981 is illustrated in Figure 42. From 1973 to at least 1982, portions of the 

Cherry Point Pacific herring population spawned at Point Roberts, Birch Point, and Hale 

Passage, as well as at Cherry Point (Figure 42) (see Figure 2 for orientation). Since 1996 the 

Cherry Point Reach has been the only section of the coast receiving spawn deposition by the 

Cherry Point population. In 2004 less than 22 km of shoreline was utilized by Cherry Point 

Pacific herring for spawning, compared to over 60 km in 1981 (Figure 42). However, shoreline 

spawning was reported to be more extensive at Cherry Point in 2004 than it had been for a 

number of years.31 Bargmann (2001) pointed out that this contraction of the utilized spawning 

habitat increases risks from anthropogenic stressors such as oil spills and contaminant releases 

near Cherry Point. 

Georgia Basin Pacific herring DPS 

The abundance time series information for the Georgia Basin Pacific herring DPS is 

presented in Figure 43. Summary statistics on population trends for the entire DPS as well as 

various subunits of the DPS are presented in Table 12. The methods for estimating trends are 

described in the general risk methods section. In 2004 the estimated total spawner biomass in 

the DPS of over 116,000 metric tons was only slightly lower than the all time high in 2003 of 

over 125,000 metric tons. The long-term trend (1973–2004) in abundance for the DPS is 1.01 

(95% CI, 1.00–1.03) and the short term trend (1990–2004) in abundance is 1.04 (95% CI, 

1.02–1.05) (Figures 44 and 45 and Table 12), indicating that Pacific herring in the DPS as a 

whole continue to increase in abundance. 

Bargmann (1998) reported that, within Washington State, estimates of natural mortality 

rates for Pacific herring increased from less than 0.4 between 1976 and 1980 to more than 0.6 

from 1990 to 1995. Some Pacific herring in Puget Sound formerly lived beyond age 10; 

however, fish older than 6 years are now rare (Bargmann 1998). Also during this time period, 

the number of age groups comprising the bulk of the populations decreased from five to two or 

three (EVS 1999). 

The WDFW classifies populations into five status categories: 1) Healthy, recent two-year 

mean abundance above or within 10% of the 25-year mean; 2) Moderately Healthy, recent twoyear mean abundance within 30% of the 25-year mean; or with high dependence on recruitment; 

86
32 See footnote 5. 33 See footnote 5. 

y = -0.1159x + 239.18

R2

 = 0.6642

5

5.5

6

6.5

7

7.5

8

8.5

9

19891990199119921993199419951996199719981999200020012002200320042005

Year

Log-transformed biomass (ln metric tons)

Figure 40. Short-term trend of Cherry Point Pacific herring spawner abundance (metric tons) from 1990 

to 2004. Data from K. Stick.32

y = -0.0711x + 149.6

R2

 = 0.8145

5

5.5

6

6.5

7

7.5

8

8.5

9

9.5

10

19711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005

Year

Log -transfor

med

biomass (

metric tons)

Figure 41. Long-term trend of Cherry Point Pacific herring spawner abundance (metric tons) from 1973 

to 2004. Data from K. Stick.33

87
Table 12. Estimates of long- and short-term trends and their 95% confidence intervals for Pacific herring 

in the Georgia Basin Pacific herring DPS. 

Herring stock/section Data years LT trend (CI) 

ST trend (CI) 

(1990–2004)

North Puget Sound 

 Cherry Point 1973–2004 0.92 (0.91–0.93) 0.89 (0.84–0.93) 

 Semiahmoo Bay 1975–2004a 1.01 (0.98–1.03) 0.94 (0.91–0.97) 

 Northwest San Juan Islands 1976–2004a 0.93 (0.84 1.03) 0.79 (0.64–0.96) 

 Interior San Juan Islands 1976–2004a 1.07 (0.98–1.15) 0.99 (0.85–1.15) 

 Samish/Portage Bay 1975–2003a 1.05 (1.01–1.09) 1.03 (0.95–1.10) 

 Fidalgo Bay 1980–2004a 1.02 (0.99–1.05) 0.93 (0.90–0.97) 

South/Central Puget Sound

 Skagit Bay 1976–2004a 1.05 (1.00–1.09) 1.16 (0.98–1.37) 

 Holmes Harbor 1976–2004a 1.05 (1.01–1.09) 1.03 (0.95–1.12) 

 Port Susan 1982–2004 0.97 (0.92–1.01) 1.04 (0.94–1.14) 

 Quartermaster Harbor 1976–2004 0.98 (0.96–0.99) 1.00 (0.95–1.06) 

 Port Orchard–Port Madison 1975–2004a 0.98 (0.94–1.01) 1.05 (0.97–1.14) 

 Port Gamble 1976–2004 0.99 (0.98–1.01) 0.95 (0.92–0.99) 

 Kilisut Harbor 1975–2004a 1.00 (0.97–1.03) 0.98 (0.90–1.07) 

 Quilcene Bay 1976–2004a 1.13 (1.07–1.20) 1.25 (1.13–1.38) 

 South Hood Canal 1976–2004a 0.97 (0.95–1.00) 0.98 (0.90–1.06) 

 Squaxin Pass 1975–2004a 1.05 (0.99–1.11) 1.08 (0.94–1.23) 

Strait of Juan de Fuca 

 Discovery Bay 1976–2004 0.89 (0.84–0.94) 0.86 (0.70–1.06) 

 Dungeness Bay 1980–2004a 0.98 (0.91–1.05) 0.81 (0.70–0.92) 

Canadian Strait of Georgia 1971–2003 1.02 (1.01–1.04) 1.05 (1.02–1.08)c

Georgia Basin DPSb 1973–2003 1.01 (1.00–1.03) 1.04 (1.02–1.05)c

a

 Missing several years of biomass estimates. b

 Based on biomass estimates of a varying number of stocks per year. c

 Data years 1990–2003. 

88
Table 13. Comparison of WDFW classifications of status of inland water Pacific herring populations of 

Washington based on three stock assessments. Data from Stout et al. (2001) and WDFW.* 

Stock status Stock status Stock status 

Stock name 1996 2000 2004 

Squaxin Pass Moderately Healthy Healthy: 185% of 25-yr mean 

healthy spawning biomass 

Quartermaster Harbor Healthy Healthy Moderately healthy: 77% of 25-yr 

mean spawning biomass 

Port Orchard/Port Madison Depressed Healthy Moderately healthy: 72% of 25-yr 

mean spawning biomass 

South Hood Canal Unknown Healthy Moderately healthy: 87% of 25-yr 

mean spawning biomass 

Quilcene Bay Healthy Healthy Healthy: 133% of 25-yr mean 

spawning biomass 

Port Gamble Healthy Healthy Depressed: 58% of 25-yr mean 

spawning biomass 

Kilisut Harbor Unknown Healthy Moderately healthy: 73% of 25-yr 

mean spawning biomass 

Discovery Bay Critical Critical Critical: 21% of 25-yr mean 

spawning biomass 

Dungeness Bay Healthy Healthy Depressed: 24% of 25-yr mean 

spawning biomass 

Port Susan Depressed Moderately Depressed: 54% of 25-yr mean 

healthy spawning biomass 

Holmes Harbor Unknown Depressed Healthy: 154% of 25-yr mean 

spawning biomass 

Skagit Bay Healthy Healthy Healthy: 169% of 25-yr mean 

spawning biomass 

Fidalgo Bay Moderately Healthy Depressed: 56% of previous 25-yr 

healthy mean spawning biomass 

Samish-Portage Bay Healthy Healthy Moderately healthy: 78% of 25-yr 

mean spawning biomass 

Interior San Juan Islands Unknown Depressed Depressed: 34% of 25-yr mean 

spawning biomass 

NW San Juan Islands Unknown Unknown Critical: 5% of 25-yr mean 

spawning biomass 

Semiahmoo Bay Healthy Depressed Depressed: 66% of 25-yr mean 

spawning biomass 

Cherry Point Depressed Critical Critical: 41% of 25-yr mean 

spawning biomass 

* K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., October 2004. 

89
0 

10 20 30 40 50 60 70 

Spawn length (km) 

Birch Point Cherry Point Hale Passage Point Roberts 

1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2

Year 

Figure 42. Kilometers of shoreline receiving late-spring Pacific herring spawn deposition at Point Roberts, Birch Point, Ch

Passage (1981–2004). Data from WDFW.34 

34 See footnote 5. 

90
35 See footnote 5. 36 D. Hay and J. Schweigert, Department of Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC, 

Canada. Pers. commun., December 2004. 37 See footnote 5. 38 See footnote 36. 

0

20000

40000

60000

80000

100000

120000

140000

1970 1975 1980 1985 1990 1995 2000 2005

Year

Bio

mass (metric tons)

Figure 43. Georgia Basin Pacific herring DPS spawner biomass (metric tons) from 1973 to 2004. Data 

from WDFW35 and DFO.36

y = 0.0377x - 63.941

R2

 = 0.5606

10.9

11

11.1

11.2

11.3

11.4

11.5

11.6

11.7

11.8

19891990199119921993199419951996199719981999200020012002200320042005

Year

Log-transfor

med biomass (ln metric tons)

Figure 44. Short-term trend of Georgia Basin Pacific herring DPS spawner abundance (metric tons) from

1990 to 2004. Data from WDFW37 and DFO.38

91
39 See footnote 5. 40 See footnote 36. 

y = 0.0248x - 38.343

R2

 = 0.5118

10.2

10.4

10.6

10.8

11

11.2

11.4

11.6

11.8

12

19711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005

Year

Log-tra

nsformed biomass (ln metric t

ons)

Figure 45. Long-term trend of Georgia Basin Pacific herring DPS spawner abundance (metric tons) from

1973 to 2004. Data from WDFW39 and DFO.40

92
3) Depressed, recent abundance well below the long-term mean, but not so low that permanent 

damage to the population is likely (i.e., recruitment failure); 4) Critical, abundance low enough 

that permanent damage to population is likely or has already occurred; 5) Extinct, no longer can 

be found in a formerly consistently utilized spawning ground; and 6) Unknown, insufficient 

assessment data to identify stock status with confidence (Lemberg et al. 1997). In 1996, WDFW 

classified status of the 18 inland water stocks as 7 in healthy condition, 2 in moderately healthy 

condition, 3 depressed, 1 critical, and 5 unknown (Table 13). Washington Department of Fish 

and Wildlife has updated these classifications twice using data through 1998 and 2004 (Table 

13). The recent update resulted in many changes in the classifications. Nine populations have 

been downgraded in status and one has increased since the 2000 status assessment (Table 13). 

The latest update classified status of the 18 stocks as 4 in healthy condition, 5 in moderately 

healthy condition, 6 depressed, and 3 critical. A new stock, Wollochet Bay, was added to 

WDFW assessments beginning in 2000, but time series of data are insufficient for analysis of the 

stock’s status. 

Population Growth Rates and Parameters 

The methods for estimating the population growth rate λ are described in the Risk 

Assessment Methods subsection above. For the Cherry Point population, the data support is very 

high that the population is decreasing (λ < 1) (Figure 46). The data observed are much more 

likely to have been produced by an intrinsically declining population rather than an intrinsically 

increasing one. 

For the Georgia Basin time series data, data support is very high that the population is 

increasing (λ > 1) (Figure 47). This means that the data are much more likely to have come from 

an intrinsically increasing population rather than an intrinsically decreasing population. Note 

that by chance, increasing time series can be observed from populations whose dynamics are 

intrinsically decreasing. However, for this time series, the observed rate of increase is high and 

the year-to-year variability is low. Such combinations are much more likely to be observed in 

intrinsically increasing populations. 

Risk Factors 

EVS (1999) provided a thorough overview of potential stressors to the Cherry Point 

Pacific herring population. Major risks to the survival of Pacific herring were summarized in 

detail in the previous Pacific herring status review under the topics of overharvesting, predation, 

loss or degradation of habitat, adverse climatic conditions, and pollution-related effects (Stout 

et al. 2001a). Risk factors identified in these two reports (EVS 1999, Stout et al. 2001a) are 

briefly reviewed in the following subsections, with particular reference to Cherry Point Pacific 

herring and to the Georgia Basin DPS. 

Physical stressors 

Climate—It is generally accepted that a climate shift occurred about 1977 that affected 

North Pacific marine ecosystems. Several studies have described decadal-scale oscillations in 

North Pacific climatic and oceanic conditions (Mantua et al. 1997). These changes have been 

associated with recruitment patterns of several groundfish species and Pacific herring 

93
Figure 46. Lambda estimates for the Cherry Point Pacific herring population and the posterior probability 

that the subpopulation experiences a 95% decline in biomass within the next 10, 20, or 50 years. 

94
0.6 0.8 1 1.2 1.4

0

5

10

15

Lambda value

Pro

b

a

bility

d

e

n

sity

fu

n

ctio

n

of la

m

b

d

a

0 0.2 0.4 0.6 0.8 1

0

500

1000

1500

Probability of 95% decline in 10 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

5

10

15

20

Probability of 95% decline in 20 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

1

2

3

Probability of 95% decline in 50 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

Figure 47. Lambda estimates for the Georgia Basin Pacific herring DPS and the posterior probability that 

the subpopulation experiences a 95% decline in biomass within the next 10, 20, or 50 years. Note 

that posterior probability of 95% decline within 10 years is essentially zero, as the line is up 

against the y-axis. 

95
(McFarlane et al. 2000). Regional, long-term temperature regimes, such as El Niño climate 

events and the Pacific Interdecadal Oscillation (PDO), have been associated with declines in 

condition of certain Pacific herring stocks (Spratt 1987, Schweigert et al. 2002). 

Schweigert et al. (2002) postulated that changing environmental conditions and resultant 

reduction in plankton availability may in part explain the decline in growth characteristics since 

1977 that are evident for many Pacific herring stocks in Alaska and British Columbia. Similar 

temporal declines in size-at-age are evident for Cherry Point Pacific herring (Figures 38 and 39), 

and most other components of the Georgia Basin Pacific herring DPS. 

Temperature—Temperature plays an important role in all stages of the life history of 

Pacific herring (Thornton 1995) and is an important risk factor to all life stages of Cherry Point 

Pacific herring (EVS 1999). Seasonal changes in temperature regulate the timing of spawning 

migrations, as well as metabolic and developmental rates. In addition, EVS (1999) indicated a 

potential interaction of temperature and increased predation on Cherry Point Pacific herring. 

Analyses of temperature trends for the U.S. part of the Pacific Northwest (Mote et al. 1999); the 

maritime portions of Oregon, Washington, and British Columbia (Mote 2003a); and the Puget 

Sound-Georgia Basin region (Mote 2003b) have shown that air temperature increased 0.8°C, 

0.9°C, and 1.5°C, in these respective regions during the twentieth century. Warming in each of 

these areas was substantially greater than the global average of 0.6°C (Mote 2003b). 

Scattergood et al. (1959) reported that water temperature at the time of Pacific herring 

spawning ranges from 3.0°C to 12.3°C on the Pacific coast of North America. Palsson (1984) 

recorded mean temperatures of 11°C and 11.5°C during two separate 1981 cohort incubation 

studies of Cherry Point Pacific herring at Birch Bay, substantially greater than the average 

temperature of 7–9°C at the time of spawning in British Columbia (Alderdice and Hourston 

1985, Tanasichuk et al. 1993). Alderdice and Velsen (1971, p. 1545) determined that “maximum 

temperature for spawning is about 10°C” for Pacific herring in North American waters. Applied 

Biomonitoring (1999), Applied Biomonitoring and Boettner (2002), and Salazar and Salazar 

(2002, 2004) reported on temperature measurements associated with caged mussel toxic 

contaminants studies along the Cherry Point Reach from 1998–2000. Mean daily water 

temperature between mid-April and mid-June exceeded 11.5°C, the screening threshold for 

possible deleterious effects on Pacific herring development, on 14 days in 1998, 9 days in 1999, 

and 2 days in 2000 (Applied Biomonitoring and Boettner 2002). Brief temperature spikes as 

high as 17–18°C were recorded in 1998 and 1999 (Salazar and Salazar 2002). Salazar and 

Salazar (2002, p. 2) stated that “these data suggest that temperature is a potentially significant 

stressor for herring egg development” along the Cherry Point Reach. 

EVS (1999) also analyzed the effects of temperature on Cherry Point Pacific herring and 

found an inverse relationship between the mean annual sea surface temperature (SST) and 

spawning biomass for the Cherry Point Pacific herring stock from 1973 to 1998. The significant 

correlations between temperature and spawning biomass, and between temperature and

mortality, indicates that regional SST is a risk factor for Cherry Point Pacific herring. 

Although temperature is not a direct cause of Pacific herring larval mortality except in 

extreme cases (Thornton 1995), SST has been correlated with the strength of year classes in 

Pacific herring (Nagasawa 2001). Temperature extremes have also been associated with larval 

96
mortality and abnormal development in laboratory studies and in the field. Wespestad and 

Gunderson (1991) reported that temperature and larval transport alone accounted for 50% of the 

recruitment variability seen in Pacific herring from the eastern Bering Sea. EVS (1999) 

considered temperature to be of moderate risk to egg and larval stages of Cherry Point Pacific 

herring. 

Salinity—Salinity in the Cherry Point region is influenced by discharge from the Fraser 

and Nooksack rivers, as well as from industrial releases and surface water runoff. Pacific herring 

have a broad salinity tolerance, but lower survival and other effects have been observed at high 

and low extremes (Alderdice and Velsen 1971). The risks are greater for egg and larval life 

stages that are more sensitive to the extremes of salinity than other life stages (Alderdice and 

Hourston 1985). These life stages are also more likely to be exposed to changing salinity 

because they are present in nearshore intertidal and subtidal habitats. 

Griffin et al. (1998) showed that initiation of sperm motility and progression to hatching 

were inhibited at higher and lower salinities than the optimum of 12–24‰ for sperm motility and 

8–24‰ for development through hatching in San Francisco Bay Pacific herring. However, 

different Pacific herring populations may tolerate greater or lesser ranges of salinity (Griffin 

et al. 1998). EVS (1999) found evidence of little, if any, relationship between salinity and the 

decline of the Cherry Point Pacific herring population. Salinity in the Strait of Georgia and 

Bellingham Bay has been relatively constant over the years, even with the influence of the 

Nooksack and Fraser rivers. In contrast, the spawning biomass of Cherry Point Pacific herring 

has decreased dramatically and recruitment of new spawners has been highly variable.

Larval Pacific herring are euryhaline, surviving best in water of salinities that are less 

than oceanic, but greater than 0‰ (Thornton 1995). Larval condition is poor if incubation 

occurs at too high a salinity (Alderdice and Velsen 1971). However, larval Pacific herring are 

capable of withstanding, for a brief time, large changes in salinity. EVS (1999) found no studyarea-specific data for salinity and instead relied on data from nearby Washington Department of 

Ecology monitoring stations. However, because it was not known whether those stations are 

representative of the nearshore, EVS (1999) was not able to draw conclusions about this risk 

factor, except to say that egg and larval life stages of the Cherry Point Pacific herring stock are 

potentially affected by salinity. 

Spawn exposure—Heavy egg loss can occur when eggs are exposed at low tide and 

subjected to desiccation by sunlight and wind (Barton and Wespestad 1980). These exposure 

effects are influenced by beach height and by egg size and number of eggs per clump (Jones 

1972). Jones (1972, p. 1123) noted that since smaller fish produce smaller eggs, any “reduction 

in mean spawner size ... could put smaller eggs further up the beach where they are less able to 

survive.” The reduction in mean size-at-age (Figures 38 and 39) and number (Figure 37) of adult 

Cherry Point Pacific herring has likely led to reduced mean egg size and clump size of spawned 

eggs, which could affect recruitment potential “if environmental factors operating in the 

intertidal zone are more detrimental to smaller eggs, eggs from smaller fish, or smaller clump 

sizes” (Jones 1972, p. 1119). 

Wind and storms—The shoreline along Cherry Point is frequently exposed to wind and 

storms. Harsh overwintering conditions can weaken spawning fish, thus reducing egg 

97
production either in number or size, and thereby reducing recruitment (Zebdi and Collie 1995). 

In addition, eggs can be lost from storm damage—normally observed as windrows of washed up 

eggs and attached vegetation (Tester and Stevenson 1948, Haegele et al. 1981, Hay and Miller 

1982). Hay and Miller (1982) estimated that about 25% of total Pacific herring egg deposition 

was lost in the vicinity of French Creek (near Qualicum Beach on the eastern shore of Vancouver 

Island) due to storm action in March 1980. Effects of this storm were felt along much of the east 

coast of Vancouver Island (Hay and Miller 1982). In addition, similar storm-induced changes in 

the physical environment during the incubation period could affect Cherry Point Pacific herring. 

That storm-induced egg mortality can occur at Cherry Point is evidenced by Meyer and Adair 

(1978, p. 53) who stated that: 

The northern Puget Sound sac-roe fishery began in 1973 after large amounts of 

herring spawn were found washed up on beaches along the eastern shore of the 

Gulf of Georgia in the spring of 1971 and 1972. The fishery was intended to 

harvest the apparent surplus. 

Alderdice and Hourston (1985, p. 61) stated that “under exposed storm conditions at exposed 

spawning locations, extension of spawning into deeper waters where other conditions for egg 

survival are less promising may provide some net survival advantage.” 

Biological stressors 

Lack of vegetation and substrate—Pacific herring have been reported to prefer native 

eelgrass (Zostera marina), rockweed (Fucus distichus), and the introduced Japanese seaweed 

(Sargassum muticum) in the intertidal zone for spawning (Taylor 1964). In addition to shallow 

eelgrass beds, subsequent studies indicated that egg deposition could occur to depths of negative 

12 m mean lower low water (MLLW) (Outram and Humphreys 1974). Diver surveys have 

indicated that red algae may be the most commonly used spawning substrate in southern British 

Columbia (Haegele et al. 1981). In northern British Columbia, where giant kelp (Macrocystis 

sp.) is much more abundant, it is frequently used as a spawning substrate (Haegele and 

Schweigert 1985). Haegele et al. (1981) conducted dive surveys in Pacific herring spawning 

grounds to assess the relation between vegetation type and use as spawning substrate. Along 

transects with mixed vegetation, 52–77% of eggs were deposited on red algae species. More 

than half of the eggs were deposited on foliose red algae (Cryptopleura sp., Prionitis sp., 

Gigartina exasperata, and Gymnogongrus leptophyllus), except on gradual slopes with wide 

spawning areas where the majority was deposited on filamentous red algae (Rhodomela larix and 

Odonthalia floccosa). On steep slopes where kelp was a significant vegetation type, 36% of 

eggs were deposited on kelp (Agarum sp. and Laminaria sp.). Along transects with mixed 

vegetation, eggs also occurred on rockweed (F. distichus, to 17%), eelgrass (Z. marina, 6–15%), 

and other brown algae (S. muticum, to 11%). A similar pattern of vegetation utilization was 

found in approximately 200 ha of diving surveys in the Strait of Georgia, but in surveys 600 km

(370 mi) north, red algae ranked second to eelgrass (Haegele and Miller 1979). 

Eelgrass occurs in near shore areas of Puget Sound and the Georgia Basin where it 

provides spawning substrate for Pacific herring. Recent surveys in Puget Sound (WyllieEcheverria et al. 2003) found that submerged eelgrass habitat had disappeared from two 

documented Pacific herring spawning sites in the San Juan Islands, Washington. Eelgrass has 

also been monitored in Puget Sound by the Washington Department of Natural Resources 

98
(WADNR) under the Submerged Vegetation Monitoring Project (Sewell et al. 2002). The Puget 

Sound Action Team (PSAT 2005) reported that WADNR detected a 4% decline in eelgrass 

between 2002 and 2003 that was mainly confined to Hood Canal and north Puget Sound, 

although the majority of the 76 monitored eelgrass beds had been stable since 2000.

Availability of suitable spawning and rearing habitat has been considered a potential risk 

factor for Cherry Point Pacific herring. EVS (1999) reported that since Pacific herring appear to 

be capable of utilizing a variety of vegetation types for spawning, at Cherry Point they could 

potentially spawn on vegetation along the entire stretch from Point Whitehorn to the Sandy Point 

Marina entrance (Figure 2). The width, slope, and exposure of the shelf along the Cherry Point 

reach that is used for spawning varies considerably from north to south and, consequently, 

vegetation used for spawning may vary from area to area or year to year (EVS 1999). However, 

EVS (1999) concluded that the width of the shelf, the availability of stable substrates for 

vegetation to attach to, and the distribution of vegetation with regard to shoreline zones could 

interact with environmental factors such as temperature, the amplitude of tidal cycles at the time 

of spawning, and predator abundance and distribution, to produce areas of the shoreline with 

different rates of egg survival. Overall, a lack of vegetation or substrate does not appear to be a 

factor limiting the areas that could potentially be utilized for spawning in the vicinity of Cherry 

Point (EVS 1999). EVS (1999) determined that impacts at the egg or juvenile life stage do not 

account for the overall stock decline 

Food supply—One of the principal food sources for Pacific herring is Neocalanus 

plumchrus, a large and nutritious calanoid copepod. Marshall and Bargmann (in prep.) reported 

that the sharp decline in Cherry Point Pacific herring abundance was caused by a sharp reduction 

in Neocalanus sp., while populations of smaller copepods such as Calanus marshallae increased. 

They also speculate that Cherry Point Pacific herring spawn in late spring in order to synchronize 

larval hatch with the emergence of N. plumchrus as an available prey item. However, EVS 

(1999) analyzed ocean productivity (chlorophyll a and invertebrate biomass) and concluded that 

that was a lack of a relationship between recruitment to the Cherry Point Pacific herring stock 

and food supply. Therefore, although food supply is a potential risk factor that affects Pacific 

herring populations, there is no time series of data directly addressing Pacific herring food 

supply for the Cherry Point population, and data from other locations were not collected over a 

sufficient time scale to show any relationship (EVS 1999).

Competition—A temporal decline in size-at-age is apparent for Cherry Point Pacific 

herring since 1973 (Figures 38 and 39). A similar decline in size-at-age occurred in British 

Columbia and in Alaska (Schweigert et al. 2002). Much of this recent (since 1973) decline in 

size-at-age may be driven by a combination of poor ocean conditions (see above) for Pacific 

herring and perhaps competition for food (Schweigert et al. 2002), particularly with the very 

abundant migratory Pacific herring population that dominates the northern SOG. Naumenko 

(2002) examined temporal variations in size-at-age for 28 Pacific herring populations in the 

northwest Pacific Ocean and showed that these populations exhibit long-term cyclic growth 

dynamics that are influenced by stock abundance and food supply. Individual growth in these 

populations was reduced in periods of very large or very low stock abundance (Naumenko 

2002). The decline in Cherry Point Pacific herring abundance and other segments of the Georgia 

Basin DPS may have allowed other forage fish species to move into the ecological niche once 

99
occupied by Pacific herring, resulting in increased competition for available food resources and a 

reduced ability for the populations to rebuild to previous levels. 

Disease—Disease is a major risk factor that can significantly affect population 

abundance of Pacific herring (Marty et al. 2003) by reducing the lifespan of adult fish and 

causing mortality of juvenile fish before they mature. Pacific herring suffer from epidemic 

diseases such as viral erythrocytic necrosis virus (VENV) and viral hemorrhagic septicemia virus 

(VHSV) (Kocan et al. 1997). Several highly virulent, endemic pathogens persist in Puget Sound 

Pacific herring that, in combination with other stressors, can result in disease outbreaks 

(Hershberger et al. 2004). For example, Carls et al. (1998) found that adult Pacific herring, 

caught in the wild and experimentally exposed to weathered crude oil, exhibited increased 

mortality and histopathologic lesions in concert with activation of VHSV, in contrast to control 

fish. Kocan et al. (2001) concluded that it was highly probable that VHSV, or any other disease 

in age-0 Pacific herring, could have an important impact on recruitment success and ultimate 

year-class strength. However, Kocan et al. (2001) found low levels of VHSV-infected wild fish 

from Puget Sound and EVS (1999) found no evidence for long-term trends or increases in 

disease outbreaks in the Cherry Point Pacific herring population. 

Parasites—A parasite of concern in risk analyses of Pacific herring is the protozoan 

Ichthyophonus hoferi (Kocan et al. 1999, Hershberger et al. 2002). This parasite infects many 

marine fish species, and has been shown in laboratory studies to be highly pathogenic for 

juvenile Pacific herring (Kocan et al. 1999), and therefore capable of causing mass mortality 

events. The prevalence of this parasite in wild populations of Pacific herring has been 

documented in coastal British Columbia (Jones and Dawe 2002), as well as in Puget Sound 

(Hershberger et al. 2002). Hershberger et al. (2002) found that prevalence of the parasite may be 

maintained in older fish in Puget Sound, noting that the parasite occurred in 12% of juveniles 

and 58% of the age-6 and older cohorts. Furthermore, the disease is maintained in the 

environment by other infected fish species (Kocan et al. 1999, Hershberger et al. 2002). Rates of 

infection by parasites in some Pacific herring stocks differ in El Niño years (Moser 1991), due to 

increased availability of prey. In addition to I. hoferi, 10 other species of parasites were recently 

identified in Pacific herring from Prince William Sound, Alaska (Marty et al. 1998). 

Predation—Spawned Pacific herring eggs provide forage for a wide variety of birds and 

intertidal invertebrates (Schmitt et al. 1994). Bird predation is suspected as the greatest source of 

egg loss, since great numbers of birds often congregate on the spawning ground. Taylor (1955) 

reported bird predation could result in 30–90% egg mortality on individual spawnings. Large 

birds, mainly diving ducks and gulls, can account for up to 80% of Pacific herring egg loss rate 

over the incubation period (Palsson 1984). The waters of Puget Sound and the Strait of Georgia 

support large numbers of wintering seabirds, such as migratory sea ducks. These seabirds are 

known to concentrate in nearshore areas in association with spawning locations for Pacific 

herring (Bayer 1980, Haegele 1993a, Sullivan et al. 2002). At Birch Bay, Washington, Palsson 

(1984) reported that diving ducks congregated around spawning beds during the first three days 

after spawning in direct response to egg deposition. Palsson (1984) also reported that surf 

scoters were the dominant avian predators recorded at Cherry Point during the Pacific herring 

spawning migration. Haegele (1993a) estimated that seabirds consumed between 3.1% and 3.8% 

of the spawn deposited in the Strait of Georgia in 1989 and 1990, and noted that seabirds may 

consume most of the Pacific herring eggs when stocks are low. Furthermore, avian predation on 

100
Pacific herring eggs also affects the macrophyta upon which eggs are deposited. Bayer (1980) 

observed 17 bird species (see Bayer 1980 for species list) grazing heavily on intertidal plants 

covered with Pacific herring eggs, which may have contributed to the patchiness and zonation of 

eelgrass. In addition to egg predation, Cleaver and Franett (1946) observed seabirds directly 

consuming juvenile Pacific herring. Logerwell and Hargreaves (1997) estimated that seabirds 

consumed between 11% and 21% of juvenile Pacific herring off Vancouver Island, Canada. 

U.S. West Coast pinnipeds include the California sea lion (Zalophus californianus), 

Steller sea lion (Eumetopias jubatus), harbor seal (Phoca vitulina), northern elephant seal 

(Mirounga angustirostris), northern fur seal (Callorhinus ursinus), and Guadalupe fur seal 

(Arctocephalus townsendi). In Puget Sound and the Strait of Georgia, pinnipeds that potentially 

prey upon Pacific herring are limited to California sea lion (Schmitt et al. 1995) and harbor seals 

(Baraff and Loughlin 2000). Harbor seals are the most abundant pinniped in Washington 

(Jeffries et al. 1996), and are an important predator. Harbor seals are opportunistic feeders 

whose diet includes fish, cephalopods, and crustaceans. In Pacific Northwest waters, fish species 

commonly eaten by harbors seals include Pacific herring, northern anchovy (Engraulis mordax), 

and various salmon and codfish species. It is estimated that Pacific herring make up nearly 6%

of the diet of California sea lions (Schmitt et al. 1995) and approximately 32% of that of harbor 

seals (Environment Canada 1998). Olesiuk (1993) reported that in the Strait of Georgia, Pacific 

hake and Pacific herring constituted 75% of the biomass consumed by harbor seals. Marine 

mammal predation remains an important risk factor to the Cherry Point Pacific herring

population (EVS 1999). 

River lamprey (Lampetra ayresi) is an important predator of Pacific salmon and Pacific 

herring. Mortality is mainly on 1-year-old Pacific herring, not the spawning 3-year-and-older 

fish. Beamish and Neville (1995) studied lamprey predation on Pacific herring in the Fraser 

River plume and estimated that mortality of Pacific herring amounted to 156 million in 1990 and 

203 million in 1991. They concluded that lamprey predation could be an important source of 

marine mortality of Pacific herring in the Strait of Georgia. 

Many species of invertebrates, including pelagic cnidarians, ctenophores, salps, and 

chaetognaths, prey on Pacific herring larvae (Schmitt et al. 1994). Purcell and Grover (1990) 

estimated zooplankton predation rates on Pacific herring larvae in Kulleet Bay, Vancouver 

Island, British Columbia. They concluded that predation, primarily by the hydromedusa 

Aequorea victoria, was a major source of Pacific herring larvae mortality.

A number of benthic marine invertebrate species also prey on Pacific herring eggs. In a 

study of epibenthic invertebrate predation of Pacific herring eggs in British Columbia, Haegele 

(1993b) estimated that egg loss due to invertebrate predation averaged 8%, with crabs 

comprising the major invertebrate predator, accounting for 60% of the egg loss. In an egg 

mortality study at two sites in Puget Sound, Palsson (1984) reported that invertebrate predators at 

Quartermaster Harbor included two mud snails (Nassarius mendicus and Mitrella gouldi). At 

Birch Bay, no snail predation was recorded but other invertebrate predators including crabs 

(Cancer productus, C. magister, and Puggetia producta), an amphipod (Anisogammarus 

pugetensis), the ochre sea star (Pisaster ochraceus), and unspecified sea anemones were present.

101
Herring larvae are eaten by juvenile fish of many species (Schmitt et al. 1994), including

Pacific salmon, Pacific hake, and walleye pollock (West 1997). Likewise, adult Pacific herring, 

including spawning and post-spawning adults, are an important prey for many marine organisms 

in Puget Sound, including Pacific salmon, Pacific cod, Pacific hake, walleye pollock, lingcod 

(Ophiodon elongates), spiny dogfish (Squalus acanthias), Pacific halibut (Hippoglossus 

stenolepis), and rockfishes (Sebastes spp.) (West 1997). During May in Central Puget Sound, 

Pacific herring have been reported to make up 60% and 26% of the prey biomass of Chinook 

(Oncorhynchus tshawytscha) and coho salmon (O. kisutch), respectively (Fresh et al. 1981). 

The predatory fish most likely to have contributed to the decline of Cherry Point Pacific 

herring is Pacific hake, a large demersal fish, which has declined in abundance in Puget Sound, 

but is suspected to be a major Pacific herring predator in open waters off the coast of Vancouver 

Island (EVS 1999). Several studies (Ware and McFarlane 1995, McFarlane et al. 1997) have 

hypothesized that a predator-prey mechanism can explain the interrelationship of rising sea 

surface temperatures, the biology of Pacific hake, and the decline of Pacific herring that utilize 

areas off southern Vancouver Island. The theory rests on the temperature-dependence of the 

northward extent of the annual summer migration of Pacific hake from California into the coastal 

waters of northern Washington and southern British Columbia. Because Pacific hake feed 

heavily on Pacific herring, and because they have a tremendous impact on the coastal ecosystem

during their summer residence (i.e., they comprise the single largest component of fish biomass 

in the summer fish community of southern British Columbia), they have the potential to 

significantly reduce Pacific herring abundance. Stocker et al. (1985) used an age-structured 

model to estimate recruitment of Pacific herring, and found that natural mortality was inversely 

related to biomass, (i.e., depensatory). They suggested that the principal mechanism for 

depensation was increased natural mortality due to predation associated with small school sizes 

at low biomass. Therefore, fish predation remains an important risk factor for the Cherry Point 

Pacific herring population, given the population’s reduced abundance (EVS 1999). 

Small larval size—In 1991, mean weight of herring larvae from two sites at Cherry Point 

were 91 μg and 75 μg, compared to a control larval weight of 120 μg (Kocan 1998). Likewise, 

Hershberger et al. (2005) showed that mean dry weights at hatch of larvae derived from naturally 

spawned Pacific herring eggs at Cherry Point in 1999 (82 μg), 2000 (95.6 μg), 2001 (133 μg), 

and 2002 (112 μg) were significantly smaller than similar larvae from other Puget Sound stocks 

in each of these years (104 μg in 1999, 112–141 μg in 2000, 151–191 μg in 2001, and 150–175 

μg in 2002). Hershberger et al. (2005) also found that mean total length of newly hatched Pacific 

herring larvae at Cherry Point in 2002 (6.0 mm) were significantly smaller than larvae from other 

Puget Sound locations (6.4–8.8 mm). Hershberger et al. (2000) detected a significantly greater 

percentage of Pacific herring larvae at Cherry Point hatched without yolk (86%), compared to 

larvae from other Puget Sound locations (up to 28%) in 2000. In addition, Hershberger et al. 

(2005) reported that yolk deficiencies in Pacific herring eggs at Cherry Point in 1999 (97%) and 

2000 (87%) were significantly greater than in other sampled Puget Sound stocks (35% in 1999 at 

Holmes Harbor and ranging from 1–33% in 2000 for a number of localities). 

Hershberger et al. (2000, 2005) proposed several scenarios to explain the observed low 

larval weight and high incidence of larvae hatching without yolk at Cherry Point, but stated that 

the ultimate causes remain undetermined. Gilardi and Gaydos (2003, p. 1) reported that 

Hershberger, Naish, and Kocan had “found that Cherry Point Pacific herring larvae had similar 

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weights and a similar incidence of developmental abnormalities regardless of whether they 

developed in the waters at Cherry Point or were incubated in clean laboratory water or were 

transplanted and developed in other areas of the Puget Sound which are considered 

uncontaminated.” Hershberger et al. (2005, p. 333) also reported that “in situ egg exposures 

indicated that these [developmental] abnormalities were not related to conditions at the [Cherry 

Point] spawning location.” 

Because low larval weight at hatch implies that Pacific herring egg sizes were also low at 

Cherry Point (see Jones 1972), it may be pertinent to examine the studies of Tanasichuk and 

Ware (1987) and Tanasichuk et al. (1993). Tanasichuk and Ware (1987, p. 1490) examined the 

relationship of fecundity and egg size in British Columbia Pacific herring and showed that “there 

is a significant trade-off between fecundity and egg size” and “that there may be an optimal egg 

size which maximizes survival during the early life history.” Tanasichuk et al. (1993) compared 

life history characteristics of SOG and Beaufort Sea Pacific herring. Both studies suggested that 

Pacific herring populations whose larvae experience higher sea temperatures would be expected 

to have smaller weight-specific egg (and larval) size to compensate for an “anticipated increase 

in predation pressure during the larval phase” (Tanasichuk et al. 1993, p. 971). This 

phenomenon is also seen among Atlantic herring, where early (winter-spring) spawning stocks 

produce larger eggs and late (summer-autumn) spawning stocks produce smaller eggs (Hempel 

and Blaxter 1967). Cherry Point Pacific herring larvae would be expected to encounter higher 

sea-surface temperatures as larvae and perhaps greater predation pressure than other local Pacific 

herring populations that spawn 2–3 months earlier. Unfortunately, Cherry Point Pacific herring 

fecundity and egg weight measurements are not available. In addition, since egg size also 

increases with adult female body size (Hay 1985) and larger, older Pacific herring spawn earlier 

than smaller, younger Pacific herring, it is important when comparing Pacific herring egg and 

larval size from different locations to use gametes from similar-sized adult female fish. 

Larval skeletal abnormalities—Kocan (1998) examined the percent of abnormal or 

deformed larvae at hatch and after seven days of growth along the Cherry Point Reach, and 

detected few significant differences from laboratory controls. Hershberger et al. (2005) detected 

a significantly larger percentage of larvae at Cherry Point in 2000 (55%) and 2001 (38%) that 

had skeletal deformities compared to Pacific herring from other Puget Sound spawning locations 

(0–14% in 2000 and 10–20% in 2001). However, the percent of larvae with skeletal 

abnormalities at Cherry Point in 2002 (7%) were within the range of abnormalities seen in other 

sample locations in Puget Sound (1–35%). Purcell et al. (1990) detected high percentages of 

abnormalities in yolk-sac (up to 25%) and post-yolk-sac (up to 68%) larvae in a relatively 

pristine spawning location on Vancouver Island, British Columbia that may have resulted from

exposure to unusually sunny, warm weather coinciding with daytime low tides during the egg 

incubation period. As mentioned above, Gilardi and Gaydos (2003, p. 1) reported that 

Hershberger, Naish, and Kocan had “found that Cherry Point Pacific herring larvae had ... a 

similar incidence of developmental abnormalities regardless of whether they developed in the 

waters at Cherry Point or were incubated in clean laboratory water or were transplanted and 

developed in other areas of the Puget Sound which are considered uncontaminated.” Likewise, 

Hershberger et al. (2005, p. 326) reported that “larval abnormalities originated primarily from

factors independent of conditions at the spawning location because they were not reproduced by 

incubation of foreign zygotes along the Cherry Point shoreline but were reproduced after the 

development of indigenous [Cherry Point] zygotes in controlled laboratory conditions.” Thus it 

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is unlikely that the high percentages of abnormal larvae detected at Cherry Point were due to 

warm, sunny weather conditions. 

Reduction in size and age at maturity—In the case of Cherry Point Pacific herring, the 

apparent reduction over time of both size-at-age (Figures 38 and 39) and age at first maturity 

from age 3 to age 2 (Figure 32) may have had a negative effect on population growth. Smaller 

body sizes likely lead to reduced fecundity, since fecundity increases exponentially with female 

weight, and smaller egg sizes and early maturity may lead to reduced longevity. Temporal and 

geographical trends in Pacific herring body size-at-age, age at maturity, and fecundity and their 

impact on stock productivity in Cherry Point Pacific herring were extensively reviewed in the 

previous status review (Stout et al. 2001a) in the sections entitled “Growth rate, body size-at-age, 

and age structure” and “Trends in Productivity” and are not repeated herein.

Anthropogenic stressors 

Fishery harvest—It is likely that the Cherry Point stock was overharvested in the mid1970s. The initial decline in stock biomass in the late 1970s and early 1980s may have been due 

to the initial high harvests. EVS (1999) indicates that total harvest of the Cherry Point 

prespawning stock biomass ranged from 4,450 short tons in 1974 to 126 short tons in 1988. No 

harvests were taken in 1981, from 1983 to 1986, or from 1997 to 1998. However, it could be 

argued that the stock was harvested during portions of the 1970s at rates that are equal to or more 

than those considered sustainable by the current scientific consensus. EVS (1999) notes that this 

pattern of initial overexploitation followed by reduced population size and greater regulatory 

control is common among new fisheries, as the Pacific herring sac roe fishery was in the early to 

mid-1970s. However, EVS (1999) noted that it was unlikely that these harvests played a major 

role in abundance declines during the 1990s, because the time elapsed since the harvest rate was 

reduced to sustainable levels is greater than the oldest recorded age class in the population (9 

years). In other words, the population that was overharvested in the 1970s has since been 

replaced at least twice. 

Habitat—Eelgrass beds, an important spawning habitat in Washington State, have been 

adversely impacted, particularly in areas of intense industrial development. Anthropogenic 

stressors on eelgrass include activities directly disturbing eelgrass beds, such as dredging and 

boat anchoring, and indirect activities that reduce light availability such as over-water structures, 

runoff that increases turbidity, and nutrient addition, which facilitates algal blooms (Sewell et al. 

2002). The adoption of a “no net loss” policy by the State of Washington has led to the creation 

of the Submerged Vegetation Monitoring Program (Berry et al. 2003). Sewell et al. (2004) 

estimated that there are approximately 200 km2

 of eelgrass in Puget Sound, with more eelgrass in 

flats stratum (60%), but more miles of coastline with fringe eelgrass habitat. 

Cherry Point proper is located south of the BP Cherry Point refinery pier (Figure 2), and 

at this point distribution of kelp beds shifts from distinctly subtidal and begins to straddle the 

boundary between the intertidal and subtidal zones. To the south of Cherry Point, kelp beds 

appear to narrow and eelgrass abundance to decline sharply with only small, scattered patches 

present down to the entrance to the Sandy Point Marina (Figure 2). According to EVS (1999), 

no eelgrass beds occur in the vicinity of the southernmost ConocoPhillips Ferndale refinery pier. 

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On nearby San Juan Island, Wyllie-Echeverria et al. (2003) documented a dramatic 

decline in eelgrass beds. Of particular concern is the loss of an entire eelgrass bed, as happened 

in Westcott Bay in the San Juan Islands between 2001 and 2003 (PSAT 2005). WADNR 

detected an overall 4% decline in eelgrass among the 76 monitored beds in Puget Sound between 

2002 and 2003. This decline was mainly confined to Hood Canal and north Puget Sound, while 

the majority of the 76 monitored eelgrass beds have been stable since 2000 (PSAT 2005). 

The decline of habitat, particularly eelgrass, at Cherry Point has been hypothesized as one 

of the factors for the decline of the Cherry Point Pacific herring stock. However, Kyte (1999, 

2000, 2001, 2002, 2003, 2004) surveyed the Cherry Point shoreline and stated that the 

distribution and quantity of submerged aquatic vegetation, which is important as Pacific herring 

spawning substrate, varied yearly due to storms, natural littoral processes, and growth or 

recession of eelgrass and macroalgal beds. He concluded that, in general, habitat conditions for 

Pacific herring spawning have been good to excellent, as evidenced by increasing heavy use of 

the vegetated areas for spawning. In any event, the potential loss of eelgrass habitat remains a 

risk factor for Cherry Point Pacific herring.

Structures—Marine structures (e.g., the BP Cherry Point refinery pier, the Alcoa Intalco 

pier, and the ConocoPhillips Ferndale refinery pier) may potentially affect littoral transport of

sediments along the Cherry Point Reach. According to EVS (1999), no site-specific studies have 

been conducted at any of the existing marine facilities along Cherry Point to investigate the 

potential impacts of those structures on wave sheltering and their effects on sedimentation. 

However, potential impacts of the existing marine facilities can be assessed in a general way by 

considering the reduction of wave energy on the sheltered side of structures and docked vessels, 

then considering how this change in wave energy might influence sediment transport behavior. 

The risk is that a significant reduction in wave energy could lead to the deposition of material in 

the “sheltered areas,” which could adversely affect Pacific herring spawning substrate. 

In their risk assessment of piers along the Cherry Point Reach, EVS (1999) concluded 

that the existing structures and docked vessels were not likely to cause substantial wave 

sheltering or increases in sedimentation. Furthermore, EVS (1999) stated that when compared to 

the total shoreline available along the Cherry Point Reach (approximately 14.5 km), the 

combined influence of these three piers impacts only a fraction of the available habitat. Thus 

any potential effects due to wave sheltering and sedimentation would be expected to be minimal 

when compared to the total available habitat. Wave sheltering and sedimentation have not 

historically been related to potential impacts on the Cherry Point Pacific herring stock. 

Nonetheless, the potential loss of spawning habitat from a variety of possible anthropogenic 

causes will remain a risk factor for Cherry Point Pacific herring. 

Shading from over-water structures inhibits the growth of marine vegetation and may 

change the spatial distribution of algae under structures. The degree of impact depends on the 

vegetation type and the design of the over-water structure. In 1992, Whatcom County estimated 

the vegetated area shaded by the three piers along the Cherry Point Reach (EVS 1999). They 

determined the depth of the vegetated zone, the linear feet of trestle that would extend over this 

zone, and the width of each trestle, and calculated the vegetated area that would be shaded. The 

BP Cherry Point refinery pier was estimated to shade 1,433 m2, the Alcoa Intalco pier 1,219 m2, 

and the ConocoPhillips Ferndale refinery pier 1,065 m2. Their estimates of vegetation depth 

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have not been confirmed and should be considered minimum estimates since they assume light to 

be direct, overhead, and unchanging. Preliminary analysis suggests that the piers do form

boundaries to the distribution both of the vegetation and the substrate. Based on aerial 

photographs, all three piers are located in vegetation gaps (EVS 1999). The effect of structures 

and shading and the attendant reduction in vegetation remains a risk factor for Cherry Point 

Pacific herring.

Vessel traffic—EVS (1999) provided a summary of marine vessel traffic likely to be 

encountered at Cherry Point. The largest tankers allowed to operate in Puget Sound displace 

125,000 dead-weight tons (dwt). They may be as long as 290 m. Cargo ships that visit the 

Alcoa Intalco pier displace approximately 40,000 dwt with a draft of 9 m. Tug boats that assist 

marine shipping also range in size and may be propelled by conventional screw propellers 

(“conventional tug”) or by V-S propellers, which consist of assemblies of vanes mounted 

vertically beneath the tug hull (“tractor tug”). The most powerful class of tractor tugs is about 

47 m long and operates at 8,000 horsepower. The bottom hull of these tugs is approximately 4 m 

below the water surface, and the propulsion assembly extends over 2 m below the hull. 

Conventionally propelled tugs have twin screws mounted nearer the water surface than to the 

bottom of the hull and range from 4,000 to 7,200 horsepower. Other marine traffic in the Cherry 

Point area includes pleasure craft, fishing vessels, and other types of commercial shipping 

vessels. 

Washington Department of Ecology estimates that approximately 95% of all tanker 

traffic into the Cherry Point area approaches through the Strait of Juan de Fuca and then 

northward through Rosario Strait. The passage through Georgia Strait, which represents the 

northern access to Cherry Point, is narrow and more restrictive to tanker traffic (EVS 1999). 

At Cherry Point, spawning Pacific herring hold in an area offshore prior to moving 

inshore to the spawning habitat. The holding area serves as a dynamic migration corridor, in the 

sense that some Pacific herring leave the holding area as others enter it. According to EVS 

(1999), the shipping lanes for tanker traffic passage to the BP Cherry Point refinery pier likely 

cross the eastern portion of this holding area, although because the approach to the BP Cherry 

Point refinery pier is always into the current, and because tidal currents reverse over a tidal cycle, 

different approaches are used. 

Assuming that the largest inbound tankers to the BP Cherry Point refinery pier draw no 

more than 14.6 m (i.e., the lowest point of the tanker’s hull is 14.6 m below the water line), they 

are not likely to have a direct effect on Pacific herring. According to EVS (1999), recent 

monitoring of Pacific herring offshore of the spawning habitat shows that the Pacific herring 

hold near the bottom in depths from 21 to 37 m below the surface, which is over 8 m beneath the 

largest vessel’s hull. Although propeller jets may extend deep enough to create a slight 

disturbance in water flow to affect the Pacific herring, it is unlikely that these effects are greater 

than those induced by tidal fluctuations (EVS 1999). It is also possible that the passage of a 

shadow caused by a moving ship would induce a type of avoidance behavior. Disruption of 

Pacific herring migration pathways by ship traffic cannot be ruled out as a potential risk factor 

for Cherry Point Pacific herring.

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Noise—It remains uncertain whether noise from vessels in the vicinity of Pacific herring 

spawning grounds would cause adverse effects (Schwarz and Greer 1984), although reaction to 

simulated marine mammal echolocation sounds (Wilson and Dill 2002) and apparent production 

of endogenous sounds (Wilson et al. 2003) suggest that Pacific herring respond to many auditory 

inputs. Fish in general show an avoidance response to vessels within 100–200 m, when the noise 

threshold is exceeded by 30 decibels (dB) (Mitson 1995). Larger ships may affect Pacific 

herring from a greater distance compared to smaller vessels (Schwarz and Greer 1984). 

Assuming that Pacific herring have a noise threshold of 75 dB and vessels generally emit noise 

levels of 145 dB in the same frequency range, Pacific herring would be able to detect the vessels 

(EVS 1999). However, it is uncertain whether they would be sufficiently disturbed to react to 

vessel sounds, given the uncertain effects of various parameters and their interactions, for 

example, whether fish are feeding or migrating, water temperature, light levels, and 

physiological condition. The Cherry Point stock has continuously spawned near the BP Cherry 

Point refinery pier, despite the elevated vessel traffic and associated noise (EVS 1999). 

Nonetheless, under some conditions, vessel noise could pose a potential risk factor to Cherry 

Point Pacific herring. 

Oil spills—According to PSAT (2005), there were a total of 223 reported “serious” oil 

spills (classified as between 25 and 10,000 gallons) between 1993 and 2003 that resulted in the 

release of over 114,000 gallons of oil into Puget Sound. Two recent oil spills in Puget Sound, at 

Point Wells in December 2003 (4,800 gallons) and in Dalco Passage in October 2004 (1,000 

gallons) “illustrate the potential destruction a major spill could cause in Puget Sound” (PSAT 

2005, p. 12). 

EVS (1999) reported that marine shipping operations at Cherry Point associated with 

operation of the BP Cherry Point refinery involve the approach, docking, dockside activities, 

undocking, and departure of crude oil tankers, refined petroleum product carriers, and tug/barge 

units. Similar operations occur at the ConocoPhillips Ferndale refinery pier. The Alcoa Intalco 

pier receives cargo ships delivering alumina or liquified propane. Dockside activities at the 

refineries include unloading crude oil, loading or unloading product, and discharging or taking 

on ballast water. Bunkering, or the loading of fuel for ship engine use, is done at Port Angeles 

and at the ConocoPhillips Ferndale refinery. 

There have been at least 47 oil spills of 10,000 gallons or more in Washington since 

1964. The Washington State Department of Ecology operates a Spills Program that monitors 

vessel entries and transits and issues spill prevention bulletins. Clearly the effect of a major oil 

spill poses a major risk to Cherry Point Pacific herring and the Georgia Basin Pacific herring 

DPS as a whole. The acute and chronic toxicological affects that release of crude oil have on 

Pacific herring and on Pacific herring populations are addressed in the following contaminants 

section. 

Ship ballast—The primary risk of ship ballast is the introduction of nonindigenous 

species that could be harmful to Pacific herring. However, another ballast-related risk factor 

concerns uptake of ballast water by ships while docked at Cherry Point. Taking on ballast has 

the potential to affect larval stages of Pacific herring by passively including Pacific herring 

larvae taken on with ballast and inadvertently transporting them when the vessel leaves the area. 

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However, EVS (1999) could find no data to quantify the risk of mortality to larval Pacific 

herring from uptake in ballast water.

EVS (1999) provided a summary of scenarios of ballast uptake at Cherry Point. While at 

the BP Cherry Point refinery pier, crude oil tankers only take on ballast through sea chests on the 

bottom of the hull measuring 1.8 m by 2.7 m. The largest tankers take on from 235,000 to 

340,000 barrels of water, or approximately 10,000,000 gallons per tanker. It is worth noting that 

large tankers discharge no ballast, so contaminants or alien marine species are not released to 

local waters. Likewise, alumina carriers at the Alcoa Intalco pier take on ballast, but do not 

discharge ballast at the pier. Since water displacement of the alumina carriers is small compared 

to that of the large tankers, the amount of ballast taken on by these vessels is proportionally 

smaller. By comparison, product ships (generally 70,000 dwt or less) may discharge ballast from

specially designed ballast tanks. Because the tanks only come in contact with ballast water, they

are presumed to be free of toxic contaminants. Crude tankers do not discharge ballast at the pier 

because they are full of crude oil upon arrival. Therefore, it is the product ships that may 

introduce exotic species into the Cherry Point region when discharging ballast water. This 

remains a risk factor for Cherry Point Pacific herring. 

General contaminants—The previous status review (Stout et al. 2001a) extensively 

reviewed the topic of environmental contaminants and their impacts on Pacific herring, relying 

heavily on information from West (1997). Contaminants considered of most concern in Puget 

Sound by Stout et al. (2001a) included 1) synthetic chlorinated organic chemicals, such as 

hexachlorobenzene, DDTs, and the polychlorinated biphenyls (PCBs); 2) polycyclic aromatic 

hydrocarbons (PAHs) from petroleum and creosoted pilings; 3) dioxins and a host of other 

organic compounds; 4) metals such as mercury, arsenic, and lead; and 5) organic matter and 

nutrients, such as nitrogen. To this list can be added endocrine-disrupting compounds and new 

toxics like PBDEs (flame retardants). The following section emphasizes studies on the issue of 

contaminants that have appeared since Stout et al. (2001a) or are of particular relevance to 

Cherry Point Pacific herring. 

Oil—Petroleum release to the aquatic environment from catastrophic spills and chronic 

release from point and nonpoint sources creates risks regarding toxicity of oil to individual 

Pacific herring and to Pacific herring populations. Prior to the 1989 Exxon Valdez oil spill 

(EVOS) in Prince William Sound, Alaska, conventional acute toxicity bioassay tests, which 

assess toxicity as the concentration that kills half of the exposed organisms after 96 hours (LC50), 

had indicated that aromatic hydrocarbons in unweathered crude oil were toxic to juvenile fishes 

(the most sensitive life history stage) at approximately 1 ppm. Most of this toxicity was assumed 

to be due to induced narcosis brought about by the 1- and 2-ringed aromatic hydrocarbons in 

crude oil—primarily benzene, toluene, ethylbenzene, and xylene (BTEX). Since these 

components of crude oil evaporate to the atmosphere within a few days of air contact, due to 

their relatively high vapor pressures, the toxic effects of oil on fish were thought to be limited to 

the first two weeks following an oil release. However, these types of toxicity tests failed to 

examine delayed mortality beyond the 96-hour exposure period and did not account for variable 

field conditions that may exacerbate risks to juvenile fish as a result of oil exposure (Rice et al. 

2000, Short et al. 2003). In addition, these short-term (4-day) assays failed to account for effects 

due to chronic exposure to partially weathered oil containing 3-, 4-, and 5-ringed hydrocarbons 

(Peterson et al. 2003). These polycyclic aromatic hydrocarbons (PAH) are more persistent in the 

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environment than mono-and di-aromatic compounds and are the second most abundant toxic 

component of crude oil, after BTEX (Rice et al. 2000, Carls et al. 2001). 

After the EVOS contaminated shoreline spawning habitat of Pacific herring, as well as 

intertidal spawning habitat of pink salmon (O. gorbuscha), a number of laboratory and field 

studies were undertaken to examine the longer term effects of crude oil on Pacific herring 

development (Brown et al. 1996, Hose et al. 1996, Kocan et al. 1996a, Norcross et al. 1996, 

Marty et al. 1997, McGurk and Brown 1996, Middaugh et al. 1998, Carls et al. 1999, 2000). 

Carls et al. (2002) has synthesized these and other studies of the toxicological impacts of the 

EVOS on Pacific herring. 

Laboratory exposure of Pacific herring eggs to solutions of PAH in seawater as low as 

0.4 ppb (0.4 μg L-1) for 4–16 days resulted in adverse effects including increased mortality, 

reduction in swimming ability, smaller length at hatch, and morphological abnormalities such as 

edema, skeletal defects, fanfold defects, and chromosomal aberrations (Carls et al. 1999). In 

close agreement with the Pacific herring studies are studies on pink salmon embryos (Marty et al. 

1997, Heintz et al. 1999, 2000), as well as on other teleost species (Couillard 2002, Middaugh 

et al. 1996, 2002, Incardona et al. 2004), which document similar developmental defects after 

PAH exposure. In addition, Barron et al. (2003) demonstrated that exposure to sunlight 

increased toxicity in PAH-exposed Pacific herring larvae 1.5- to 48-fold (depending on PAH 

levels in larval tissue) over controls. Early life stages of Pacific herring are particularly 

vulnerable to photo-enhanced toxicity of PAH, since they occur in nearshore tidal and subtidal 

habitats as eggs and embryos, and within the photic zone as larvae (Barron et al. 2003). 

Adult Pacific herring exposed to oil during the EVOS exhibited elevated tissue PAH 

concentrations and increased levels of hepatic necrosis (Marty et al. 1999). In addition, Carls 

et al. (1998) found that adult Pacific herring caught in the wild and experimentally exposed to 

weathered crude oil exhibited increased mortality and histopathologic lesions in concert with 

activation of viral hemorrhagic septicemia virus, presumably due to depressed immune function, 

in contrast to control fish. Kocan et al. (1996b) and Johnson et al. (1997) examined reproductive 

success in Pacific herring from oiled sites 3 years and 6 years after the EVOS, respectively. 

Kocan et al. (1996b) compared Pacific herring from only two sites, one oiled and one un-oiled, 

and detected a lower percent hatch and more morphologically abnormal larvae at the oiled site. 

However, Johnson et al. (1997) compared Pacific herring from four sites in Prince William

Sound with three sites from Southeast Alaska and were unable to detect any evidence of 

reproductive impairment of Prince William Sound Pacific herring due to the EVOS in 1995, 6 

years after the spill. 

Low-level PAH exposure has also been shown to result in decreased growth and marine 

survival in pink salmon (Heintz et al. 2000). Pink salmon exposed as embryos to 1–20 ppb PAH, 

and control fish, were tagged as juveniles and released to the environment. Following 16 months 

at sea, salmon initially exposed to ≈5 ppb total PAH experienced a 15% decrease in marine 

survival (Heintz et al. 2000), while exposure “of about 20 ppb eventually killed half the fish 

before they could reproduce” (Carls et al. 2001, p. 401). The implication of the Heintz et al. 

(2000) study is that repeated low-level hydrocarbon exposure can negatively affect fitness and 

productivity of pink salmon and presumably Pacific herring populations. Several recent reviews 

of the scientific literature (Carls et al. 2001, 2002, Short et al. 2003) have suggested that the 

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41 See Footnote 3. 42 See Footnote 3. 43 See Footnote 3. 44 See Footnote 3. 45 See Footnote 3.

toxicity threshold for aqueous PAHs should be lowered to 1 ppb (1 μg × L-1) to adequately 

protect juvenile fish rearing habitats. 

PSAT (2005, p. 5) reporting on long-term monitoring of contaminated sediments in Puget 

Sound, stated that “although levels of PAHs are lower than their peak during the coal-burning era 

of the early twentieth century, levels increased from 1989 to 2000 at four out of 10 sampling 

sites: Strait of Georgia, Bellingham Bay, East Anderson Island, and Inner Budd Inlet.” 

Creosote—Vines et al. (2000) examined the effects of diffusible compounds (including 

PAHs, cresols, and phenols) in weathered creosote-treated pilings on Pacific herring 

development. Vines et al. (2000, p. 226) stated that 

water-diffusible compounds from creosote-treated pilings disrupted normal 

development in the Pacific herring in a concentration-dependent manner. Effects 

included cessation of early development, abnormal cardiovascular function, 

alterations in the movement of developing embryos/larvae, decreased hatching 

success, and abnormal larval morphology. 

Vines et al. (2000, p. 225) reported that suboptimal salinities enhanced the negative impacts of 

creosote on larval morphology and hatching success, and that “similar effects were observed in 

embryos collected from creosoted pilings in San Francisco Bay.” 

PAH contamination studies at Cherry Point—West and co-authors (West et al. 2004, 

West41) examined total PAHs in spawned Pacific herring eggs from Cherry Point, Fidalgo Bay, 

Quilcene Bay, Port Orchard, and Quartermaster Harbor. PAH levels exceeded the larval effects 

threshold of 22 ppb in spawned Pacific herring eggs, as determined by Carls et al. (1999), at 

other spawning locations in Puget Sound (e.g., Port Orchard), but not at Cherry Point (West et al. 

2004, West42). 

Because PAHs do not accumulate in fish, exposure of adult Pacific herring to PAH in 

Puget Sound was estimated by West et al. (2001), West,43 and O’Neill and West (2002) as 

fluorescing aromatic compounds (FACs), a measure of PAH-metabolites, in Pacific herring bile. 

Analysis of Pacific herring from six locations—Cherry Point, Semiahmoo Bay, Fidalgo Bay, 

Port Orchard, Quartermaster Harbor, and Squaxin Pass (West et al. 2001, West,44 O’Neill and 

West 2002)—indicated that “Pacific herring from Central and Southern Puget Sound had higher 

FACs than those from the Northern Sound and Southern Georgia Basin” (West et al. 2001, 

p. 45). Examination of total PAHs in Dungeness crab hepatopancreas samples from four Puget 

Sound locations and in English sole (Pleuronectes vetulus) (as biliary FACs) from 24 Puget 

Sound locations (both studies included Cherry Point) showed similar trends, with lower PAH or 

biliary FAC concentrations in the northern areas such as Cherry Point and higher concentrations 

in the more urbanized South Sound.45

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46 See footnote 3. 47 See footnote 3. 48 See footnote 3. 49 See footnote 3. 50 See footnote 3. 

Marine mussels (Mytilus spp.) have little ability to metabolize hydrocarbons (see 

references in Carls et al. 2002), and because they are filter feeders their body burden of total 

PAH contamination serves as an indication of the extent of biologically available oil 

contamination. Applied Biomonitoring (1999), Applied Biomonitoring and Boettner (2002), and 

Salazar and Salazar (2002, 2004) reported on studies that used bioaccumulation of PAHs over a 

60-day exposure period in tissues of caged mussels as a proxy for the potential total PAH 

available to Pacific herring embryos and larvae along the Cherry Point Reach in 1998–2000, and 

at three other sites in Puget Sound in 2000. Between 1998 and 2000, the concentration of PAH 

in mussels indicated levels that “approached those associated with adverse effects on herring 

embryo-larval development” (Salazar and Salazar 2004, p. 1). However, exposure of early 

Pacific herring life stages and adult mussels likely differ in duration, magnitude, and timing, as 

well as in exposure pathways (Salazar and Salazar 2004). Applied Biomonitoring and Boettner 

(2002, p. 4) reported that “PAH concentrations measured in mussel tissues were lowest at Cherry 

Point Reach” and were progressively greater at Fidalgo Bay, Port Gamble, and Brownsville (Port 

Orchard-Port Madison stock) (Salazar and Salazar 2002). 

Organochlorines—Polychlorinated biphenyls (PCBs) and organochlorine pesticides 

(DDTs and hexachlorobenzene (HCB)) were measured as composites from whole fish collected 

at Lambert Channel (Denby Island/Hornby Island) in the northern SOG (Figure 3) and at Cherry 

Point, Semiahmoo Bay, Port Orchard, Squaxin Pass (O’Neill and West 2002) and Quartermaster 

Harbor46 (Figure 10) in Puget Sound, beginning in 1999. These chemical analyses were limited 

to adult males of age 2–4 to minimize variation between sites due to potential variation in age 

and reproductive condition (O’Neill and West 2002). Although lipid levels varied among the 

stocks, when lipid content variation was accounted for, total PCBs in Pacific herring from

Squaxin Pass, Quartermaster Harbor and Port Orchard were significantly higher than in fish from

the three northern sites: Cherry Point, Semiahmoo Bay and Denman/Hornby (O’Neill and West 

2002, West47). Higher concentrations of PCBs were also observed in south Puget Sound 

locations compared to more northern locations (West et al. 2001, West48). Significantly lower 

concentrations of HCB were detected in whole bodies of Pacific herring from Cherry Point 

compared to all other collection locations (O’Neill and West 2002, West49). 

West50 compared PCB levels in Pacific herring embryos sampled between 3 and 10 days 

of age at Cherry Point, Fidalgo Bay, Quilcene Bay, Port Orchard, and Quartermaster Harbor in 

Puget Sound and detected significantly higher concentrations only at Quartermaster Harbor. 

PCB concentrations from the other sites were not significantly different from one another. 

Trace metals—Applied Biomonitoring and Boettner (2002) examined bioaccumulation 

of arsenic, mercury, cadmium, copper, lead, zinc, and selenium in mussels deployed for 60 days 

along the Cherry Point Reach, and at Fidalgo Bay, Port Gamble, and Brownsville (within the 

Port Orchard-Port Madison Pacific herring spawning grounds). Although all mussels 

accumulated metals, the concentrations were “lower than those known to elicit effects” (Applied 

Biomonitoring and Boettner 2002, p. 112) in either mussels or Pacific herring. However, as 

111
Applied Biomonitoring and Boettner (2002, p. 112) stated, these effect levels “are based 

primarily on acute effects by measuring mortality endpoints that could underestimate potential 

chronic effects from long-term exposures to low metal concentrations in the field.” 

Application of IUCN Categories 

IUCN (2004, p. 18) recommends using biomass as an “index of abundance appropriate to 

the taxon” when evaluating marine fish population declines, since assessing declines in the 

number of mature individuals may underestimate the severity of the decline in situations where 

reduction in the mean age and size of individuals is also occurring. Therefore we have used 

biomass as an index of abundance for Pacific herring IUCN risk assessments. 

The IUCN population reduction criteria call for measuring decline “over the longer of 10 

years or 3 generations” (IUCN 2004, p. 10). A simple definition of generation time is the 

average age of the total number of parents (spawners) in the population. If generation time 

“varies under threat ... [then] pre-disturbance generation length should be used” (IUCN 2004, p. 

18). Calculating the average age of the number of spawning adults over time in the Cherry Point 

population indicates that generation time stood at about 5 years in the mid-1970s and has been 

below 3 years for most of the past 15 years (Figure 48). This indicates that a pre-decline 

generation length of 5 years and a three-generation time of 15 years are the most appropriate 

scales over which to assess the decline of the Cherry Point population in light of the IUCN 

decline criteria. Similar temporal analysis of SOG Pacific herring (Figure 49) indicates that 

generation time is closer to 4 years for this portion of the DPS. Although the time series of data 

is less complete for other components of the Washington State portion of the DPS, generation 

time for several WDFW stocks appears to be somewhat less than either Cherry Point or SOG 

Pacific herring, ranging from 2.5 to 4 years. We chose a three-generation time of 15 years over 

which to analyze declining populations as being the most precautionary. 

Over the three-generation time of 15 years, the overall biomass of the Georgia Basin 

Pacific herring DPS has increased approximately 107%, while the Cherry Point Pacific herring 

population has undergone a 54% decline (Table 14). Under the IUCN decline criteria, a 

reduction in population size of this magnitude “where the reduction or its causes may not have 

ceased or may not be understood or may not be reversible” (IUCN 2004, p. 29), would place 

Cherry Point Pacific herring in the IUCN “Endangered” category. 

Results of Modified Risk Matrix for the Georgia Basin 

Pacific Herring DPS 

Members of the BRT were asked to rate the overall risk to the Georgia Basin Pacific 

herring DPS using the risk matrix described in the above “Risk Assessment Methods” section, 

with 1 representing very low risk and 5 representing high risk of extinction in the near future, for 

the four viability criteria: abundance, growth rate/productivity, spatial structure, and diversity. 

112
Table 14. Results of application of the IUCN decline criteria to possible subpopulations within the 

Georgia Basin Pacific herring DPS. All abundances are given as metric tons of spawner biomass. 

Estimated values (in italics) were derived from extrapolation of linear equations of existing 

abundance data for missing years. (Methods described in IUCN 2004). Category designations: 

LC, least concern; NT, near threatened; E, endangered; CE, critically endangered. 

Subpopulation 

Past 

biomass 

Present 

biomass 

(closest 

to 2004) 

Current 

subpopulation 

estimate 

Subpopulation 3 

generations ago

(5-year mean 

generation time) 

Estimated 

3-generation 

reduction 

(=15 years) 

IUCN 

category

Bute Inlet 400 

(1973) 

350 350 465 25% NT 

North SOG 11,516 

(1973) 

97,557 97,557 37,971 157%

increase 

LC 

Eastern SOG 

Inlets 

232 

(1973) 

817 

(2001)

16 600 large 

increase 

LC 

South SOG + 

North Puget 

Sound 

5,214 

(1973) 

8,659 8,659 7,890 10%

increase 

LC 

Strait of Juan de 

Fuca 

675 

(1976) 

249 249 1,332 81% CE 

Cherry Point 11,767 

(1973) 

1,573 1,573 3,398 54% E 

South/Central

Puget Sound 

1,058 

(1975) 

7,062 7,062 5,507 28%

increase 

LC 

Squaxin Pass 270 

(1975) 

751 751 260 189%

increase 

LC 

Georgia Basin 

DPS 

57,124 

(1975) 

116,201 116,201 56,098 107%

increase 

LC 

113
51 See footnote 5. 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

19731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004

Year

Weighted average age of spa

w

ners

Figure 48. Weighted average age of spawning Pacific herring in the Cherry Point Pacific herring 

population from 1973 to 2004. Data from WDFW.51

Abundance 

BRT scores for abundance ranged from 1 to 2, with a modal score of 1. A score of 1 

represents “very low risk” and a score of 2 represents “low risk.” In this context, very low risk 

means that it is unlikely that current trends and levels of abundance contribute significantly to 

risk of extinction for the DPS, either by itself or in combination with other factors. Low risk 

means that it is unlikely that current trends and levels of abundance contribute significantly to 

risk of extinction by itself, but some concern that they may, in combination with other factors. 

Comments on the abundance criterion included consideration that the overall DPS is at 

historically high levels of abundance since monitoring began in the 1930s, both in estimated 

tonnage (recent abundance is well over 100,000 metric tons) and numbers of Pacific herring 

(estimated at more than half a billion mature Pacific herring); however, the decline of Cherry 

Point Pacific herring from 24 million fish in 2003 to 14 million in 2004 is troubling. 

Growth Rate/Productivity 

BRT scores for growth rate and productivity of the DPS ranged from 1 to 2, with a modal 

score of 2. Again, a score of 1 represents “very low risk” and a score of 2 represents “low risk.” 

114
0.0

1.0

2.0

3.0

4.0

5.0

6.0

1973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003

Year

Wei

g

hted average age

of spaw

ners

Figure 49. Weighted average age of spawning Pacific herring in the Strait of Georgia region from 1973 

to 2004. Data from Schweigert (2004, Appendix 1.4). 

In this context, very low risk means that it is unlikely that population productivity (growth rate) 

contributes significantly to risk of extinction for the DPS, either by itself or in combination with 

other factors. Low risk means that it is unlikely that population productivity (growth rate) 

contributes significantly to risk of extinction by itself, but some concern that it may, in 

combination with other factors. Comments on the growth rate/productivity criterion included 

consideration that overall the DPS is highly productive with the overall population trend and 

lambda (λ) very positive. This was contrasted with some periods in the past (early to mid-1960s) 

when the overall DPS was in steep decline. In addition, it was noted that despite these past 

declines, some subpopulations have shown very high productivity levels, indicating the 

resiliency and ability to rebound inherent in these subpopulations. It was also noted that the 

recent short-term trend is very positive for the whole DPS and that recruitment is staying high, 

even though there is an apparent increase in adult mortality possibly correlated with increased 

harbor seal predation and disease factors (other risk factors are also likely at work here). 

Spatial Structure and Connectivity 

BRT scores for spatial structure and connectivity ranged from 1 to 4, with a modal score 

of 2. A large majority of the BRT scored this category as 1 (very low risk) or 2 (low risk). 

Small minorities of the BRT scored this category as either 3 (moderate risk) or 4 (increasing 

risk). In this context, very low risk means that it is unlikely that population spatial structure and 

connectivity contribute significantly to risk of extinction for the DPS, either by themselves or in 

115
combination with other factors. Low risk means that it is unlikely that population spatial 

structure and connectivity contribute significantly to risk of extinction by themselves, but some 

concern that they may, in combination with other factors. Moderate risk means that population 

spatial structure and connectivity contribute significantly to long-term risk of extinction, but do 

not by themselves constitute a danger of extinction in the near future. Increasing risk means that 

population spatial structure and connectivity contribute significantly to long-term risk of 

extinction and are likely to contribute to short-term risk of extinction in the foreseeable future. 

Comments on spatial structure and connectivity criteria included observations that there are no 

gaps in the geographic range of spawning within the DPS, that all or most historically occupied 

areas continue to experience spawn events, and that there has been little loss of connectivity 

between any populations, except those with low abundance. It was also noted that although 

increasing population trends are not uniform across the DPS (central and northeastern parts of 

the DPS show declines), the tagging data indicates that there is likely high connectivity 

throughout the DPS, so these declining trends would not be a major concern in the context of a 

metapopulation. It was noted that an estimated 22% of SOG Pacific herring emigrate to other 

regions of British Columbia while 16% immigrate into the SOG from other regions of British 

Columbia (Hay et al. 2001a, their table 5). Other comments indicated concerns that the bulk of 

the spawning distribution and most of the abundance and productivity in the DPS has become

spatially compacted, especially in the northern half of the DPS. However, this concern was 

tempered by the feeling that this spatial compaction may be a natural phenomenon. 

Diversity 

BRT scores for diversity ranged from 1 to 3, with a modal score of 2. A small minority 

of the BRT scored this category as 1 (very low risk), while a larger minority scored this criterion 

as 3 (moderate risk). In this context, very low risk means that it is unlikely that diversity 

contributes significantly to risk of extinction for the DPS, either by itself or in combination with 

other factors. Low risk means that it is unlikely that diversity contributes significantly to risk of 

extinction by itself, but some concern that it may, in combination with other factors. Moderate 

risk means that diversity contributes significantly to long-term risk of extinction, but does not in 

itself constitute a danger of extinction in the near future. Comments on the diversity criterion 

included observations that diversity in spawn timing is still normally distributed around a bellshaped curve, that there has been little change in the natural range of long-term spawn timing 

within and between populations, that diverse migration still exists in the DPS in the form of 

nonmigratory and migratory Pacific herring, and that that there has been no apparent genetic loss 

comparable to other marine species, although long-term data on this topic are limited. Other 

comments included concerns that the DPS’s life history diversity has apparently declined over 

time with a compressed age structure (few old fish), precipitous decline in late-spawning Pacific 

herring populations, and an apparent decline in nonmigratory inlet populations on the mainland 

or eastern side of the SOG. In addition, it appears that there has been a northward shift in the 

spawning core area of the DPS, but this may be a natural phenomenon and the DPS is still very 

productive. It was noted that although life history diversity may be declining, since fewer 

nonmigratory Pacific herring are observed in the SOG, it is difficult to differentiate between 

“migratory” and “nonmigratory” life history types. It is unclear whether these life history 

characters are specific to certain populations or present to some degree in all or most Pacific 

herring spawning aggregates in the SOG and Puget Sound. 

116
Recent Events 

The BRT did not identify any specific “recent events” that might have predictable 

consequences for DPS status in the future but have occurred too recently to be reflected in the 

population data. Past events that were recognized as already having had a positive effect on the 

DPS were the closing of certain fisheries, a possible Pacific Decadal Oscillation (PDO) shift to 

colder climate conditions, a decrease in predation on Pacific herring by Pacific hake due to 

declining hake size-at-age and loss of larger, older hake in Puget Sound and the SOG, and a 

decrease in certain pollutants in Puget Sound and the SOG. Past events that were recognized as 

already having had a negative effect on the DPS were long-term temperature increase, declines 

in local eelgrass beds (Wyllie-Echeverria et al. 2003), an apparent increase in harbor seal 

predation in inshore waters (Olesiuk 1993, Baraff and Loughlin 2000) and hake predation in 

offshore waters (Ware and McFarlane 1995), loss of shoreline spawning habitat in Puget Sound 

and the SOG (WADNR 2004, PSAT 2005), and an apparent increase in prevalence of certain 

parasites like Ichthyophonus hoferi (Hershberger et al. 2002). 

Risk Determination 

Although not adopted in this review, application of the IUCN decline criteria to the 

Georgia Basin Pacific herring DPS would have resulted in this DPS being placed in the Least 

Concern (LC) category. However, as indicated above, the Pacific herring BRT adopted risk 

procedures utilized in recent salmonid status assessments. The outcome of this process resulted 

in the BRT classifying risk to the Georgia Basin Pacific herring DPS as 1) very low to low for 

abundance concerns, 2) very low to low for growth rate and productivity concerns, 3) very low to 

increasing risk for spatial structure and connectivity concerns, and 4) very low to moderate risk 

for diversity concerns. The BRT did not identify any specific “recent events” that might have 

predictable consequences for DPS status in the future but have occurred too recently to be 

reflected in the population data. The BRT’s overall risk assessment conclusions are further 

elucidated in the “Conclusions: Risk Assessment” section near the end of this document. 

117
Significant Portion of the Range of the Georgia 

Basin DPS Question 

Previous Findings on the “Significant Portion 

of its Range” Question 

The significant portion of the Georgia Basin Pacific herring range issue was discussed at 

length by the previous Pacific herring BRT from the perspectives of biomass and distribution of 

spawning habitat. The previous Pacific herring status review (Stout et al. 2001a, p. 145) related 

that: 

...some stocks within the Georgia Basin, such as Cherry Point and Discovery 

Bay, have declined to such an extent that they may meet the IUCN criteria to be 

considered “vulnerable.” Although the BRT recognized that herring populations 

in north Puget Sound and Puget Sound proper may be vulnerable to extinction, 

these populations [i.e., Cherry Point] represent a relatively small portion of the 

overall DPS of herring in the Georgia Basin. 

Although the BRT recognized that Cherry Point Pacific herring is an important component of the 

diversity within the Georgia Basin DPS, the consensus opinion of the previous BRT as described 

in Stout et al. (2001a) was that Cherry Point Pacific herring did not represent a significant 

portion of the range of the overall Georgia Basin Pacific herring DPS. 

Approaches to the “Significant Portion of its Range” Question 

Pacific herring in this area of the Northwest Pacific appear to roughly fit the classical 

concept of a metapopulation over reasonable spatial and temporal scales (Ware et al. 2000, Ware 

and Schweigert 2001, 2002, Ware and Tovey 2004) (see Herring and the Metapopulation 

Concept on page 9). Therefore, it is challenging and difficult to apply the significant portion of 

the range test to the Georgia Basin DPS, which for the most part functions as a metapopulation, 

where some populations are always going to be in decline while others are on the rise. 

Nevertheless, there is also some evidence that some populations in the DPS are more distinctive 

than others. The vast majority of Pacific herring in the Canadian SOG migrate to offshore 

feeding areas each spring immediately after spawning and then return in the late fall and early 

winter of each year prior to spawning (Stevenson 1955, Taylor 1964, DFO 2004). In contrast, a 

number of small resident populations are believed to spend their entire lives in coastal inlets and 

bays or in the Canadian SOG itself and to forgo extensive seasonal offshore migrations 

(Stevenson 1955, Taylor 1964, Hay 1985). Penttila (1986) also postulated that some proportion 

of adult Pacific herring remain in Puget Sound throughout the summer while others migrate to 

offshore feeding grounds. However, it is unclear whether Pacific herring nonmigratory life 

history diversity is structured on a geographic framework or is spread amongst all spawning 

118
locations. Spawn timing separation could also promote isolation and thus development of 

subpopulation structure, as is the case with Cherry Point Pacific herring. 

The BRT approached the “significant portion of its range” question for the Georgia Basin 

Pacific herring DPS in a two-step process. First, we asked the question: “Are there 

subpopulations or components of the Georgia Basin Pacific herring DPS that can be identified as 

relatively independent from one another on the basis of ecological, life history, or genetic 

diversity criteria?” The types of data that are relevant to providing an answer to this first 

question are essentially the same as those examined on page 13 in the Evidence Supporting 

Discreteness and Significance Decisions section. Second, we asked: “Is the DPS at risk in a 

significant portion of its range, such that loss of the at-risk components or subpopulations would 

pose a substantial risk to long-term viability of the DPS?” In order to differentiate between a 

species that is threatened or endangered throughout its entire range and one that is threatened or 

endangered only in a significant portion of its range, the BRT recognized that the answer to the 

second question rests largely on the time frame for which the question is asked. In other words, 

some portions of the DPS may be needed for viability of the DPS in a time frame that is beyond 

the foreseeable future—long-term climate or ecosystem changes may cause certain diversity 

elements of the DPS to become more important to the DPS’s viability over very long time frames 

(i.e., centuries). 

In attempting to identify components of the Georgia Basin DPS that may represent 

independent subpopulations we have adapted concepts and methods for identification of 

“demographically independent populations” developed by McElhany et al. (2000) and various 

Technical Recovery Teams (TRTs) that are developing recovery plans for Pacific salmon ESUs 

that have been listed as threatened or endangered under the ESA (see Northwest Salmon 

Recovery Planning website: http://www.nwfsc.noaa.gov/trt/index.html). The various TRTs have 

identified current and historical salmon populations using a variety of data sources including: 1) 

documented historical presence, 2) drainage size and structure, 3) geographic isolation by 

distance or elevation, 4) genetic attributes, 5) phenotypic characteristics, 6) environmental 

characteristics, and 7) population dynamics and size. Each of the TRTs have fine-tuned the 

process and methods for identifying demographically independent populations in ESUs under 

their purview, and the reader is directed to documents published by the TRTs for details 

(Ruckelshaus et al. in press, Interior Columbia Basin TRT 2003, Myers et al. 2006, Lawson et al. 

2004, Lindley et al. 2004). Identifying these population groups may be useful to the TRTs for 

several reasons. The first is that such groups represent life history genetic diversity within the 

ESU, and maintenance of this diversity is important for long-term ESU persistence (McElhany et 

al. 2000). In addition, the problem of ESU risk would be simplified by identifying independent

populations whose viability could then be assessed as individual units. 

Evidence for Demographically Independent Subpopulations 

When the BRT considered the DPS question, Cherry Point Pacific herring was deemed a 

discrete population; however, it was not considered to be significant to the species of Pacific 

herring as a whole. Evidence presented above in the DPS analysis can reasonably be taken to 

propose that Cherry Point Pacific herring represent a “demographically independent 

subpopulation” within the DPS. Therefore, evidence cited below will focus on the question of 

119
whether we can identify any additional parts of the Georgia Basin DPS, other than Cherry Point, 

that may represent demographically independent subpopulations. 

Although Pacific herring spend, at most, 5% of their lifetime on or near a particular 

spawning ground, Pacific herring populations are traditionally defined by the boundaries of their 

spawning grounds. In Washington, Pacific herring occupying each of these spawning grounds 

are presumed to represent discrete stocks by WDFW (Lemberg et al. 1997, O’Toole et al. 2000). 

This assumption is based on “stock specific characteristics such as strong site specificity, unique 

growth characteristics, distinctive spawning time and prespawner holding area behavior” and 

“early meristic studies which concluded that heterogeneity exists among herring samples taken 

from various spawning areas throughout Puget Sound (Chapman et al. 1941)” (Lemberg et al. 

1997, p. 4). 

Although Pacific herring have been documented as spawning at over 1,300 locations in 

British Columbia (Hay and Kronlund 1987, Hay and McCarter 1999, 2004a), DFO currently 

recognizes only five Pacific herring management regions in British Columbia: 1) Queen 

Charlotte Islands, 2) North Coast (Prince Rupert District), 3) Central Coast, 4) Strait of Georgia, 

and 5) West Coast Vancouver Island (Figure 4). Johnstone Strait is not considered a 

management region at this time, although it was in the past. Each of these regions is further 

divided into Statistical Areas, which are further divided into sections (= subareas), each of which 

is named and numbered (Hay and McCarter 2004a). Schweigert (unpubl. data, p. 3) stated that a 

location within a section is an “artificial construct, usually a local geographic name used to 

identify a section of shoreline” and that within a section, “locations are often contiguous and 

often differ markedly in size.”

Spawn Timing 

The small South Hood Canal Pacific herring stock spawns at the extreme southern end of 

Hood Canal (Lemberg et al. 1997) and spawning “is relatively early, beginning in January and 

finished by early March” (O’Toole et al. 2000, p. 5). The data illustrated in Table 1 indicates 

that peak spawn timing at Quartermaster Harbor is also earlier than most other Puget Sound 

locations. Spawning at Holmes Harbor begins “relatively late in the year, occurring in early to 

mid-April” (O’Toole et al. 2000, p. 6) (Table 1). Comparison of the range of peak spawning as 

the day of the year (corrected for leap years) in Puget Sound and the SOG indicates that spawn 

timing is generally earlier in the South Sound than in more northern locations within the DPS 

(Figure 50). 

Spawn Location and Spawning Behavior 

The Squaxin Pass Pacific herring stock occupies the southernmost spawning locale in 

Puget Sound (Figure 10) and exhibits unusual spawning behavior, commonly depositing spawn 

subtidally on rocks, gravel, and marine algae due to the lack of eelgrass in the area (Lemberg 

et al. 1997, O’Toole et al. 2000). The Port Susan Pacific herring stock, in Central Puget Sound 

(Figure 10), also occasionally deposits spawn on rocks and gravel due to a lack of marine algae 

on the west shoreline of Port Susan (Lemberg et al. 1997, O’Toole et al. 2000). 

120
52 See footnote 5. 

Figure 50. Spawn timing of Pacific herring in British Columbia herring sections (represented as mean 

day of the year [DOY] for all spawn observations) and in WDFW herring stock units (represented 

as range of DOY during peak spawning). Data from DFO (2004) and WDFW.52

121
Pacific herring spawning in Squaxin Pass and South Hood Canal in Puget Sound, and 

Bute Inlet (Herring Section 134), Jervis Inlet (Herring Section 164), and Sechelt Inlet (Herring 

Section 165) in the northern part of the SOG are geographically distant from other spawning 

locations and are spawning at the heads of inlets (Figure 10). These latter characteristics have 

been associated with development of local resident Pacific herring populations (Stevenson 1955, 

Taylor 1964). 

Annulus Patterns 

Trumble (1980, 1983) described differences in the character and quality of Pacific 

herring scales that indicated that Pacific herring from Case Inlet (Squaxin Pass) grew rapidly 

initially but showed very little growth after age 3. Other stocks of Pacific herring in Puget 

Sound, including Cherry Point, showed scale growth to continue after age 3. 

Growth Rate and Body Size-at-age 

Ware (1985) attempted to use Pacific herring growth patterns to separate stocks at the 

regional level in British Columbia. Ware (1985, p. 134) postulated that “variations in size at age 

presumably reflect differences in the spatial distribution of the stocks during the late spring and 

summer feeding period.” Ware (1985, p. 135) found that Pacific herring growth patterns contain 

“some circumstantial information on distributions and degree of mixing that can be used in 

association with other characteristics for stock identification.” However, “when growth 

conditions are favorable, particularly when the population is declining, the average weight at age 

can increase by as much as 50%, and the age at first maturity can decrease by 1 or 2 yr” (Ware 

1985, p. 137). Thus any evaluation of growth pattern differences in Pacific herring should 

include a determination of the temporal stability of the observed patterns (Begg et al. 1999). 

Problems may also arise in comparing differences in length and weight data collected by 

different investigators for different stocks that may vary in their degree of maturation (Hay 

1985). 

Schweigert (1991) applied multivariate statistical analyses to 3 years of mean length, 

mean weight, and age structure data at ages 3–6 for 26 spawning populations of Pacific herring 

in British Columbia. Schweigert (1991, p. 2375) stated that these analyzes “indicated stock 

separation on a smaller spatial scale” than is currently recognized. In reference to the SOG, 

Schweigert (1991) found evidence that Pacific herring spawning in Johnstone Strait and Strait of 

Georgia proper are distinct from one another and that Jervis Inlet (Sections 163 and 164) is a 

distinct stock from the rest of the Strait of Georgia. Other than Jervis Inlet, Schweigert (1991) 

was unable to detect strong differentiation of individual spawning areas between Lambert 

Channel (Sections 141–143), Powell River (Section 152), Nanoose Bay (Section 172), and 

Deepwater Bay (Section 132) (Figure 10). There was “an indication that stocks from Deepwater 

Bay and Powell River may differ from the other more southerly [SOG] areas, but the evidence is 

not conclusive” (Schweigert 1991, p. 2370). 

As stated previously, Trumble (1979, 1980) described statistically significant differences 

in mean growth rate and length-at-age data for three populations of Pacific herring sampled in 

the mid-1970s in Puget Sound: 1) Case Inlet (Squaxin Pass stock), 2) Hale Passage (Kitsap 

County)-Carr Inlet (unknown stock), and 3) southern Strait of Georgia purse seine catch (Cherry 

122
53 See footnote 5. 

Point stock). Trumble (1979, 1980) fit length-at-age data for these three areas to the von 

Bertalanffy growth equation and used a least-squares technique for statistical comparison. 

Trumble (1980, p. 105) stated that: 

Strait of Georgia [Cherry Point] herring [were] consistently larger (L∞ = 263 mm) 

and continually growing (K = 0.36). In contrast, fish from Case Inlet [likely 

Squaxin Pass stock] grow rapidly to age 3 (K = 0.59), then grow very slowly to a 

small size (L∞ = 197 mm). Fish from Hale Passage-Carr Inlet [unknown stock] 

show intermediate size (L∞ = 230 mm) and growth rate (K = 0.48). Two of the 

three von Bertalanffy growth parameters, L∞ and K, showed significant 

differences between the three areas at the 1 percent level when compared using 

least squares analysis. 

Gonyea and Trumble (1983) expanded on Trumble’s (1979, 1980) growth studies and 

added North Hood Canal (Quilcene Bay stock) and Protection Island (most likely Discovery Bay 

stock) Pacific herring to the analysis. They found no significant differences in von Bertalanffy 

growth parameters between North Hood Canal and Protection Island samples, which were also 

similar to the growth parameters for the Hale Passage (Kitsap County)-Carr Inlet sample. In 

addition, Buchanan (1985) reported on the identification of a minor group of Pacific herring 

spawning in the Fidalgo Bay-Padilla Bay region that were differentiated from other stocks on the 

basis of their small size at age, scale pattern, and advanced maturity stage. 

The smaller length- and weight-at-age of adult Squaxin Pass and Fidalgo Bay Pacific 

herring compared to a large number of other Pacific herring samples from two sites on WCVI 

and to other available locations in Puget Sound and the SOG from 1990 to 2002 is illustrated in 

Figures 20, 21, 28, and 29. As mentioned above, data for these comparisons were derived from

midwater trawl samples53 or seine gear samples (Hamer and Schweigert 1990, 1992, 1993, 1995, 

1996, Hamer and Midgley 1997, 1999, Midgley and Hamer 1999, Midgley and Schweigert 2000, 

2002a, 2002b, 2002c) obtained during the spawn season for each stock or herring section. All 

British Columbia data were from collections with a majority of the fish expressing a maturity 

index of 4 or higher. Length in all cases was recorded as standard length (Gonyea 1985, Hamer 

1989). 

Over the period 1990–2002, mean length of Squaxin Pass Pacific herring at age 3 was 

significantly (P ≤ 0.05) smaller than mean length of Cherry Point, Semiahmoo Bay, Port Susan, 

Port Gamble, Kilisut Harbor, Quartermaster Harbor, and all the Canadian sections except Powell 

River (Figure 20 and Table 3). At age 6, mean length of Squaxin Pass Pacific herring was 

significantly (P ≤ 0.05) smaller than mean length of Cherry Point, Semiahmoo Bay, Port 

Gamble, and all Canadian sections except Powell River (Figure 21 and Table 5). At both age 3 

and age 6, mean length of Squaxin Pass Pacific herring was not significantly (P ≤ 0.05) different 

from Samish/Portage bays, Fidalgo Bay, Port Orchard-Port Madison, and Powell River (Tables 3 

and 5). 

Over the period 1990–2002, mean weight of Squaxin Pass Pacific herring at age 3 was 

significantly (P ≤ 0.05) smaller than mean weight of Cherry Point, Port Susan, Port Gamble, 

Kilisut Harbor, and all the Canadian sections except Powell River (Figure 28 and Table 4). At 

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age 6, mean weight of Squaxin Pass Pacific herring was significantly (P ≤ 0.05) smaller than 

mean weight of only Cherry Point, Semiahmoo Bay, and three of the seven British Columbia 

herring sections (Figure 29 and Table 6). 

Similarly, Fidalgo Bay Pacific herring over the period 1990–2002, had statistically 

(P ≤ 0.05) smaller mean lengths and weights than all the Canadian Pacific herring sections 

except for Powell River, at both age 3 and age 6 (Figures 20, 21, 28, and 29, and Tables 3–6). 

However, at age 3, Fidalgo Bay Pacific herring were not statistically smaller than Interior San 

Juan Islands, Samish/Portage bays, Skagit Bay, Port Orchard-Port Madison, Quartermaster 

Harbor, and Squaxin Pass for length, nor smaller than this list of stocks and Semiahmoo Bay for 

weight (Tables 3 and 4). At age 6, Fidalgo Bay Pacific herring mean length and weight were 

statistically (P ≤ 0.05) different from all samples except Samish/Portage bays, Squaxin Pass, and 

Powell River (Figures 21 and 29 and Tables 5 and 6). 

At age 3, Baynes Sound Pacific herring (Section 142) over the period 1990–2002 were 

statistically (P ≤ 0.05) larger in mean length from all but Nootka Sound, West Barkley Sound, 

Nanoose Bay, and Swanson Channel (Table 3) and had a statistically (P ≤ 0.05) greater mean 

weight than all but Cherry Point and West Barkley Sound (Table 4). However, by age 6, these 

differences for Baynes Sound Pacific herring are for the most part not apparent (Figures 21 and 

29 and Tables 5 and 6). Unlike Cherry Point Pacific herring, Baynes Sound Pacific herring 

during the period 1976–1980 did not appear to have mean length (Figure 30) or weight (Figure 

31) values that set them apart from other samples in the analysis. 

Morphological Differentiation 

Numerous researchers have attempted to separate races or stocks of Pacific herring on the 

basis of differences in body proportions or meristic characters. These differences may be due 

either to environmental or hereditary factors, and it is not possible to determine the underlying 

causes of these differences with the data available to the BRT. In addition, morphometric and 

meristic differences between groups of fish are not normally apparent in individual fish but only 

in the mean value of a large number of individuals. 

Taylor (1964) noted that besides analysis of tag returns, the second main method of 

identifying Pacific herring populations in British Columbia was based on variations in the 

number of vertebrae, which varies within the range of 48 to 55 vertebrae. McHugh (1954, p. 

149) reviewed meristic and morphometric studies on Pacific herring and stated that “the number 

of vertebrae is capable of modification by temperature during early development, so that in any 

one locality the mean vertebral number may vary from year to year.” Tester (1937), and later 

McHugh (1954), confirmed that the mean vertebral count in Pacific herring populations 

increases with latitude. Nevertheless, Tester (1937) examined meristic and morphometric 

variation (vertebrae count, head length, length to dorsal fin insertion) in Pacific herring from 19 

localities in British Columbia, and, as in earlier studies, found differences in mean vertebral 

counts to be most informative for stock discrimination. Tester (1937) concluded that meristic 

characters could be used to separate SOG Pacific herring into three fairly discrete populations: 1) 

Point Grey (near Vancouver, British Columbia), 2) Granite Bay (North Quadra Island), and 3) 

Saltspring Island-Departure Bay-Nanoose Bay (Figure 3). In a later paper, Tester (1938) stated 

that “variation in the number of vertebrae and certain other meristic characters in fishes is caused 

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in part at least by variation in environmental conditions, notably water temperature” (Tester 

1938, p. 71). This statement was based in part on evidence that the mean count of vertebrae in 

successive year classes of Pacific herring from Barkley Sound on the west coast of Vancouver 

Island varies inversely with water temperature at the time of spawning and early development 

(Tester 1938). In a later paper, Tester (1949) found this relationship to hold in general for 

Pacific herring from the entire west coast of Vancouver Island. McHugh (1942) also found 

significant differences in vertebral counts of juvenile Pacific herring from the same year class 

sampled at a number of localities within the Strait of Georgia. 

In Washington State, Chapman et al. (1941) and Katz (1942) compared mean vertebral 

counts between Pacific herring collected at 11 locations in the years 1936 and 1937: 

1) Wollochet Bay (in south Puget Sound), 2) Poulsbo (Port Orchard-Port Madison stock), 

3) Holmes Harbor, 4) Hale Passage (Samish Bay-Portage Bay stock), 5) Seal Rock (Quilcene 

Bay stock), 6) Birch Bay (Cherry Point stock), 7) Point Migley (Lummi Island), 8) Willapa Bay, 

9) East Sound (Interior San Juan Islands stock), 10) Gig Harbor, and 11) Steamboat Island 

(Squaxin Pass stock). Comparison of Pacific herring samples from Willapa Bay, Wollochet Bay, 

and Birch Bay revealed “good separation of the mean vertebral counts in the two- and three-year 

age classes, but in the four-, five-, and six-year-olds, the differences of the mean vertebral counts 

were so slight as to cast doubt upon the significance of their difference” (Katz 1942, p. 14). Katz 

(1942, p. 14–15) stated that: 

the older age classes of the herring of Washington fail to show a significant 

difference in their mean vertebral counts and cannot, therefore, be designated as 

races if vertebral differences are to be used as a racial criterion. Whether this lack 

of racial distinctiveness in the older age classes is due to intermingling or to other 

causes cannot be determined with the scanty data on hand. 

Katz (1942) also observed that annual variation in mean vertebral counts of Pacific 

herring was greater for the Wollochet Bay aggregation in southern Puget Sound than in the Birch 

Bay aggregation, whose spawning location was closer to the open ocean. Katz (1942, p. 22) 

postulated that the greater variation in the Wollochet Bay vertebral counts “might be due to a 

greater temperature fluctuation of the southern waters of the Sound.” 

Otolith Chemistry 

As stated previously, Gao et al. (2001) analyzed oxygen and carbon isotope ratios in 

otoliths from spawning Pacific herring collected at Cherry Point in north Puget Sound and at Port 

Orchard and Squaxin Pass in south Puget Sound. Isotope ratios from nuclei of otoliths from the 

two southern Puget Sound samples were not significantly different from one another; however, 

Cherry Point otoliths were significantly different from the two southern Puget Sound samples. 

The Port Orchard and Squaxin Pass isotope ratios suggested that Pacific herring from this 

location experience higher salinities as larvae and juveniles than Pacific herring from Cherry 

Point. However, Gao et al. (2001, p. 2117) noted that “there are some crossing samples in the 

database.” Their figure 2 shows that isotope ratios from 3 of the 32 Cherry Point fish fell well 

within the range of values shown for the other two sites. This overlap may indicate some degree 

of mixing of Pacific herring between the two areas or that water conditions characteristic of 

south Puget Sound may also occur in the areas frequented by Cherry Point Pacific herring during 

early life stages. Gao et al. (2001) also studied isotope ratios of second summer (1999) otolith 

125
rings in these three Pacific herring stocks. The results indicated that most south Puget Sound 

Pacific herring were rearing in high salinity conditions and were therefore “moving to the ocean” 

(migratory stock) and that most Cherry Point Pacific herring with otolith isotope ratios indicative 

of lower salinities “might still remain in the spawning ground” (Gao et al. 2001, p. 2115) 

(nonmigratory stock). This result is surprising because nonmigratory Pacific herring would be 

expected to be slow growing and previous studies (based on limited tagging data and the 

relatively high growth rate of Cherry Point Pacific herring) had speculated that Cherry Point 

Pacific herring migrate to feed in offshore waters. Gao et al. (2001) did not consider the 

possibility that migratory fish may have been merely feeding deeper in the water column where 

salinity is higher than nonmigratory fish. 

Tagging 

Results of Pacific herring tagging operations in Washington State and British Columbia 

were reviewed in the previous status review (Stout et al. 2001a). The following discussion and 

Figures 51–54 provide more detail on results of previous Washington State tagging efforts and 

review documents related to tagging that have been released since the previous status review. 

Tagging information specific to Cherry Point Pacific herring was discussed on page 61 in the 

subsection entitled “Artificial Tagging.” 

Heyamoto and Pasquale (1961) presented results of Washington State Pacific herring 

tagging studies from 1953 to 1958. Until 1957, when Washington State Pacific herring reduction

fisheries began, recovery of tags was almost entirely dependent on the Canadian reduction 

fisheries. Besides 1953, when about 45% of the fish were tagged with external Petersen tags, all 

fish were tagged with internal metal tags. Buchanan (1986) and O’Toole et al. (2000) also 

reviewed the results of Washington State Pacific herring tagging at 1) Quilcene Bay, Holmes 

Harbor, and Brownsville-Miller Bay (Port Orchard-Port Madison stock) of spawning fish in the 

1950s; 2) Bellingham Bay in February 1958; and 3) Point Roberts in March 1958 (Semiahmoo 

Bay stock). Two populations in the first tagging group had some fish return to their tag release 

sites in subsequent spawning seasons; two Holmes Harbor tags were recovered at Holmes 

Harbor five years after tagging (Figure 51) and Port Orchard-Port Madison had one fish returned 

after 3 years (Figure 52) (Heyamoto and Pasquale 1961). All three of the populations in the first 

tagging group had tag returns from either the fall of the year of tagging, or in subsequent years, 

in the Canadian reduction fishery in the southeast Vancouver Island region (Figures 51–53) 

(Heyamoto and Pasquale 1961, Hourston 1981b, his table 2.36). Other Canadian recoveries 

included one Holmes Harbor (Figure 51) and four Quilcene Bay (Figure 53) Pacific herring, 

tagged in summer fisheries, recovered at Swiftsure Bank off the southwestern tip of Vancouver 

Island (Taylor 1973). At least three Quilcene Bay fish tagged in April 1956 were recovered in 

the subsequent winter fishery (December 1956) in Deepwater Bay at the extreme southern end of 

Johnstone Strait (Figure 53). 

Over 6,000 Pacific herring were tagged during February 1958 in Bellingham Bay. Most 

of the recoveries from this tagging study occurred in the same year of tagging in Bellingham

Bay, although four fish were recovered in the Southeast Vancouver Island region and two were 

recovered during winter fisheries on the west coast of Vancouver Island (Heyamoto and 

Pasquale 1961, Taylor 1973, his table 5). Over 4,000 Pacific herring were tagged in March 1958 

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Figure 51. Tagging and recovery locations of over 21,000 Pacific herring tagged on the spawning 

grounds at Holmes Harbor during March of 1953 and April of 1955–1957. Black dot indicates 

site of tagging and circled numbers indicate number of tag recoveries at the approximate recovery

location. Data from Taylor et al. 1956, Heyamoto and Pasquale 1961, Taylor 1973, Hourston

1981, and Buchanan 1986.

Figure 52. Tagging and recovery locations of over 7,300 Pacific herring tagged on the spawning grounds 

at Port Orchard-Port Madison (Miller Bay and Brownsville) during March of 1953–1955. Black 

dot indicates site of tagging and circled numbers indicate number of tag recoveries at the 

approximate recovery location. Data from Taylor et al. 1956, Heyamoto and Pasquale 1961, 

Hourston 1981, and Buchanan 1986. 

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Figure 53. Tagging and recovery locations of 6,000 Pacific herring tagged on the spawning grounds at 

Quilcene Bay (Hood Canal) during April 1953 and 1956. Black dot indicates site of tagging and 

circled numbers indicate number of tag recoveries at the approximate recovery location. Data 

from Taylor and Outram 1955, Heyamoto and Pasquale 1961, Taylor 1973, Hourston 1981, and

Buchanan 1986. 

Figure 54. Tagging and recovery locations of over 4,000 Pacific herring tagged on the spawning grounds 

at Semiahmoo Bay (Boundary Bay) during March of 1958. Black dot indicates site of tagging

and circled numbers indicate number of tag recoveries at the approximate recovery location. 

Data from Heyamoto and Pasquale 1961, Taylor 1973, Hourston 1981, and Buchanan 1986. 

128
at Boundary Bay (Semiahmoo Bay stock). Five of these Semiahmoo Bay Pacific herring were 

recovered off the west coast of Vancouver Island during winter fisheries of 1958–59 (Figure 54) 

(Heyamoto and Pasquale 1961, Taylor 1973, his table 5), and a number of fish were recovered 

during summer and fall in the Canadian southeast Vancouver Island region (Figure 54) 

(Heyamoto and Pasquale 1961, Hourston 1981b, Buchanan 1986). Buchanan (1985, p. 9–10) 

reported that 33 of the Semiahmoo Bay Pacific herring “were returned from the Bellingham

fishery” in 1958–59, although (Heyamoto and Pasquale 1961) record only 15 tag returns to 

Bellingham Bay (Figure 54). Taylor (1973, p. 9) stated that: 

These recoveries suggest that movement of herring from the Puget Sound, the San 

Juan Islands, and the Boundary Bay-Bellingham Bay regions into British 

Columbia is mostly from the adjacent areas and is probably no greater than

between adjacent stocks of similar size in B.C. The recoveries on Swiftsure Bank 

and on the west coast of Vancouver Island suggest that the American stocks 

tagged perhaps move to offshore summer feeding grounds in the same way as the 

Canadian Strait of Georgia stocks. 

Buchanan (1986, p. 158) reported that from 12,000 Pacific herring tagged in the summer of 1965 

on Swiftsure Bank, off the west coast of Vancouver Island, 2 were recovered in “the western San 

Juan Islands, 3 from Pt. Roberts, 1 from Bellingham Bay, and 2 from one of these areas.” 

Migratory and Nonmigratory Pacific Herring 

The vast majority of Pacific herring in the SOG migrate to offshore feeding areas each 

spring immediately after spawning and then return in the late fall and early winter of each year 

prior to spawning (Stevenson 1955, Taylor 1964, DFO 2004). In contrast, a number of small 

resident populations are believed to spend their entire lives in coastal inlets and bays or in the 

SOG itself and to forgo extensive seasonal offshore migrations (Stevenson 1955, Taylor 1964, 

Hay 1985). Penttila (1986) also postulated that some proportion of adult Pacific herring remain 

in Puget Sound throughout the summer while others migrate to offshore feeding grounds. 

In a summary of Pacific herring tagging studies from 1936 to 1951, Stevenson (1955) 

reported that he was able to distinguish migratory and nonmigratory (resident) Pacific herring in 

British Columbia, based on 1) population abundance, 2) seasonal migration (tagging), 3) growth 

and age composition, 4) location of spawning grounds, and 5) homogeneity of individual 

spawning runs. In particular, Stevenson (1955, p. 34) recognized migratory populations in the 

SOG on the “middle east coast of Vancouver Island” and on the “lower east coast of Vancouver 

Island.” Small resident Pacific herring populations were identified by Stevenson (1955, p. 34) 

“in the long inlets of the north central, south central and upper east coast regions,” areas that are 

outside of the SOG. However, Stevenson (1955, p. 34) also noted that “the presence within ... 

[the middle east coast of Vancouver Island] sub-district of resident or partially resident stocks, as 

well as a migratory stock, resulted in a relatively complicated situation.” These resident 

populations were “relatively slow-growing, suggesting that their summer feeding areas are less 

productive than the offshore feeding areas of the migratory stocks” (Stevenson 1955, p. 34). 

Stevenson (1955, p. 34) contrasted the Pacific herring population from the middle east coast of 

Vancouver Island that “showed the greatest emigration” and thus “was the least independent 

stock” with “the runs within the population of the lower east coast of Vancouver Island [that] 

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appeared to be freely mixing and homogeneous showing no differential emigration outside the 

sub-district.” 

Taylor (1964) also recognized two types of Pacific herring in British Columbia, based on 

their migration patterns: large migratory populations that migrate to the open ocean to feed and 

minor local populations that are found towards the heads of inlets or as resident populations that 

remain in inshore regions throughout the year. According to Taylor (1964), separation of these 

two types of Pacific herring is based on 1) population abundance (migratory populations greatly 

exceed the local populations in abundance), 2) seasonal migration (minor local stocks stay 

inshore throughout the year, while the large migratory stocks feed offshore during the summer 

and return to inshore waters in the fall and winter), 3) growth and age composition (minor local 

populations have a slower growth rate), 4) location of spawning grounds (small local stocks tend 

to spawn at the heads of inlets and large migratory stocks spawn in more exposed regions such as 

near the mouths of inlets), and 5) homogeneity of individual stocks (minor stocks are complex 

assemblages of small individual runs, whereas various runs of the large migratory stocks are 

similar to one another). Taylor (1964, p. 57) identified a different type of small resident Pacific 

herring that: 

occur in the middle and lower east coast subdistricts where they provide the basis 

of small summer fisheries: probably the three best known are the Active Pass, 

Porlier Pass and Point Grey stocks [in Herring Sections 173, 182, and 291 

respectively]. ... They appear to be not so much separate stocks as residual 

stocks, fish that were a part of the major migratory population but failed to go 

offshore after spawning. This is indicated by their similar rates of growth and age 

composition. 

Likewise, Schweigert (1991, p. 2374) stated that, “significant numbers of adult nonmigratory 

herring are found each year in the various tidally active passes throughout the Gulf Islands 

lending further support to the existence of ... a discrete stock.” Ware (1985) postulated that 

some of the resident stocks grow more slowly than migratory stocks due to the poorer production 

of food in the nearshore environment. Hay et al. (1999, p. 16) stated that, “the issue of the status 

of non-migratory herring may be the most significant problem for current herring management.” 

Furthermore, Hay et al. (1999, 2001a) noted that although recent spawn deposition estimates are 

high for most areas of the SOG, spawning has declined in some local areas (Hay and McCarter

1999) and there has been an apparent decline in the number of Pacific herring that reside in the 

SOG in summer. Hay et al. (1999, p. 16) suggested that: 

One potential explanation for this is that non-migratory herring represent distinct 

biological stocks, perhaps genetically differentiated, and that their numbers have 

declined. ... An alternative explanation is that these non-migratory herring are 

simply part of the major herring stocks that choose not to migrate. The option to 

migrate or remain resident may be trophically determined and affected by climatic 

conditions. 

Hay et al. (1999, p. 16) pointed out that in British Columbia some individual tagged Pacific 

herring were recaptured in the same sections and even locations that they were tagged in, and 

that “this apparent fidelity may reflect the life history of a non-migratory or sedentary fish that 

never really leaves an area.” 

130
In regards to potential small resident inlet populations of Pacific herring in the SOG, the 

DFO Integrated Fisheries Management Plan for Roe Herring (DFO 2000, p. 13–14) refers to: 

spawning populations using the heads of mainland channels or fjords, including 

... all of the inlets in ... Georgia Strait. These areas have records of spawning 

that often are inconsistent in time, indicating varying degrees of utilization of

these areas. At this time, however, we cannot rule out the possibility that one or 

more of these areas may support a genetically unique herring stock. ... The 

confinement of the fishery to the large central populations ensures that the small 

marginal populations, mainly in inlets and fjords, are protected or conserved. 

This is especially important because these small populations of herring, like other 

fish species, may have special significance in the maintenance of genetic 

diversity. 

DFO (2002, p. 2) had this to say about nonmigratory Pacific herring in the SOG: 

All herring spawning within the Strait [of Georgia] are assumed to belong to a 

single stock that migrates into the SG in the late fall and leaves, after spawning, in 

March. Many areas in the Strait retain some resident or non-migratory herring 

throughout the summer, but the distribution and abundance of non-migratory fish 

changes among years. 

Penttila (1986, p. 73) postulated that: 

although it has been presumed that Puget Sound adult herring are migratory, there 

is now indication that this is not totally the case. It may in fact be a variable 

phenomenon for some proportion of these fish. 

Trumble (1983) stated that many juvenile Pacific herring in Puget Sound overwinter in 

southern and central Puget Sound and migrate to Pacific Ocean feeding grounds in March to 

July, not returning until their first year of maturity. Adult Pacific herring were thought to 

migrate, on an annual, basis between summer feeding grounds (mostly off the Washington and 

British Columbia coasts) and Puget Sound spawning grounds (Trumble 1983). Lassuy (1989, 

p. 6) suggested that growth and size-at-age differences between Squaxin Pass and Cherry Point 

Pacific herring “may result because the Strait of Georgia stocks [Cherry Point] are migratory 

while the Case Inlet [Squaxin Pass] stocks are resident.” 

Genetic Variation 

Overall, the genetic analysis of Beacham et al. (2001, 2002) supported the 

metapopulation view of Pacific herring populations in British Columbia, at least among the large 

migratory stocks. Besides the single sample from a single year at Cherry Point, a few other 

samples from remotely sited “resident” Pacific herring in British Columbia mainland inlets were 

identified as being somewhat more distinct (Beacham et al. 2001, 2002) relative to the larger 

assessment stocks. Several Beacham et al. (2001, 2002) samples were obtained from locations 

within the boundaries of the Georgia Basin Pacific herring DPS and deserve some comment. A 

single sample from Bute Inlet (Section 134) was not significantly different from other putative 

populations in Johnstone Strait. However, “differentiation was observed between the Johnstone 

Strait stock and herring in more northern and southern regions in British Columbia” (Beacham

et al. 2002, p. 9). Beacham et al. (2001, 2002) also reported that no population differentiation 

131
was detected among samples from three putative populations along the east coast of Vancouver 

Island. When data from these three putative western SOG populations were pooled and 

compared to single samples from Bargain Harbour and Secret Cove (both in Section 163, 

Malaspina Strait) on the mainland (east) coast of the SOG, no significant differences were 

detected between Bargain Harbour and the Vancouver Island population, although significant 

differentiation was observed between the Secret Cove sample and the Vancouver Island 

population at 5 of 13 loci. Beacham et al. (2001, 2002) also observed significant differentiation 

between a single sample from Victoria Harbour (Portage Inlet/Esquimault Harbour) and all other 

samples, including Cherry Point and more northern samples in the SOG. In all cases, these 

differences need to be evaluated by further sampling to ensure they are stable over time

(Beacham et al. 2001, 2002). 

Results of the microsatellite DNA study of Small et al. (2004) suggest that a number of 

genetically discrete population aggregations may exist in Puget Sound. There was a small 

degree of genetic differentiation among sampling sites and in some cases between years within a 

site within Puget Sound. Besides Cherry Point Pacific herring, samples from Squaxin Pass were 

also somewhat differentiated from other collection sites and “formed a branch with 77% 

bootstrap support” (Small et al. 2004, p. 3). The BRT hypothesized that the Puget Sound Pacific 

herring populations, particularly in the South Sound, may be characterized by a degree of 

isolation similar to other inlet locations in British Columbia. In some cases it was possible for 

the BRT to hypothesize a mechanism for some level of demographic isolation. For example, 

temporal differences in spawning time (Cherry Point) or geographic isolation (Squaxin Pass) 

could result in the observed levels of genetic distinctiveness. 

Possible Subpopulations in the Georgia Basin DPS 

The Pacific herring BRT examined subpopulation structure of the Georgia Basin Pacific 

herring DPS using the above demographically independent approach, which is essentially a 

metapopulation approach. It was evident that some local subpopulations have distinguishing 

characteristics such as discrete and persistent spawning location, discrete spawn timing, 

phenotypic distinctiveness (mean length-at-age, weight-at-age, or growth rate), contaminant 

profiles, otolith chemistry, parasite incidence, migration behavior, and genetic distinctiveness 

(variation in microsatellite DNA allele frequency). Temporal variation (comparison between 

1970s and 1990s) in some growth parameters were noted within subpopulations; however, 

differences between subpopulations were generally stable and maintained over time (see Begg 

et al. 1999). These data indicate that some subpopulations in the DPS may be more 

reproductively isolated than others. This observation is most consistent with the mixed structure 

metapopulation model as articulated by Harrison and Taylor (1997), which accounts for more 

isolated subpopulations operating within a metapopulation where most of the subpopulations are 

connected by higher rates of exchange. Based on the above information, the BRT concluded the 

DPS could provisionally be divided into the following eight demographically identifiable 

subpopulations: 

1. Cherry Point—Microsatellite DNA allele frequency variation, spawn timing, 

geographical location (exposed spawning location), growth rate, and contaminant profiles 

indicate that the Cherry Point Pacific herring population is discrete compared to most 

other Pacific herring in the DPS. 

132
2. Squaxin Pass—Microsatellite DNA allele frequency variation, geographical location 

(inlet population), growth rate, and spawning behavior indicate relative discreteness. 

3. South/Central Puget Sound (Skagit Bay, Port Susan, Kilisut Harbor, Holmes Harbor, Port 

Gamble, Quilcene Bay, South Hood Canal, Port Orchard/Port Madison, Quartermaster 

Harbor, and Wollochet Bay)—It is difficult to subdivide this WDFW management unit, 

with the exception of Squaxin Pass. The geographical location (inlet population) of the 

South Hood Canal stock may indicate distinctiveness, although life history data are 

nonexistent. 

4. Strait of Juan de Fuca (Discovery Bay, Dungeness Bay, Sooke Harbour, Victoria 

Harbour)—This unit may be distinctive based on its geographical location (early entry 

into relatively open ocean conditions of Strait of Juan de Fuca). Relationship to North 

Puget Sound plus Southern SOG is uncertain. 

5. Bute Inlet (BC Herring Section 134)—This unit may be distinctive on basis of 

geographical location (inlet population) and supposed migration behavior. 

6. Eastern SOG Inlets (BC Herring Sections 162, 163, 164, 165, plus sections 292 and 280, 

which have had intermittent spawn)—This unit may be distinctive on basis of

geographical location (inlet populations) and supposed migration behavior. Schweigert 

(1991) showed Jervis Inlet as distinct based on multivariate analyses of size-at-age and 

age composition. 

7. Northern SOG (BC Herring Sections 135, 136, 151, 152, 141, 142, 143, 172)—It is 

difficult to subdivide this unit. Relationship to North Puget Sound plus Southern SOG is 

uncertain. This is the large, clearly migratory, component of the DPS. 

8. North Puget Sound plus Southern SOG (BC Herring Sections 173, 181, 182, 191, 192, 

plus Semiahmoo Bay, Samish/Portage Bays, NW San Juan Islands, Interior San Juan 

Islands, and Fidalgo Bay)—Lack of data makes it difficult to subdivide this unit. 

Relationship to large Northern SOG migratory subpopulation is uncertain. There are past 

indications of intermingling of spawning locations for nonmigratory and migratory 

Pacific herring. 

The distinctiveness of nonmigratory SOG Pacific herring (historically identified in 

Jervis/Sechelt Inlets [Eastern SOG], Bute Inlet, and in the Gulf Islands) and nonmigratory Puget 

Sound Pacific herring is largely uncertain, as is the biological distinctiveness among inlet 

populations. 

The number and boundaries of these proposed subpopulations within the DPS are inexact 

and subject to revision when additional data are acquired. Their main usefulness at this time is to 

provide some degree of spatial structure to the BRT’s analysis of the significant portion of the 

DPS’s range question (see Figure 55). 

133
Figure 55. Geographic distribution of eight proposed subpopulations of Pacific herring in the Georgia 

Basin DPS. Washington stock abbreviations are shown in Table 1 and British Columbia herring 

section designations are shown in Figure 10. 

134
Extinction Risk of Possible Subpopulations 

in the Georgia Basin DPS 

Abundance and Productivity 

The time series of estimated spawner biomass in metric tonnage for each of the eight 

proposed Georgia Basin Pacific herring subpopulations is provided in Table 15 and graphically 

presented in Figures 56–63. The abundance data series begins in 1973, when Washington State 

data are first available. Short-term (1990–2004) and long-term (1973–2004) trends in biomass 

for these subpopulations are compared graphically in Figures 64 and 65. The North SOG 

subpopulation is significantly larger than any other subpopulation in the DPS and is likely the 

healthiest in the DPS. Four of the subpopulations (Cherry Point, Strait of Juan de Fuca, Eastern 

SOG Inlets, and Bute Inlet) have long-term trends less than one (Figure 64), and three (Cherry 

Point, Strait of Juan de Fuca, and Bute Inlet) have short-term trends less than one (Figure 65), 

indicating these subpopulations are in decline over these time periods. However, there is a great 

deal of uncertainty about the trend of the Eastern SOG Inlets subpopulation, as indicated by the 

large confidence intervals, that is likely due to the high variability, and absence of data in some

years (Figure 59). 

Summary statistics on population trends are presented in Table 16. The methods for 

estimating trends and population growth rate (λ) are described in the previous risk assessment 

methods section. For the North SOG time series data (Figure 66), data support is very high that 

λ > 1 (population increasing). This means that the data are much more likely to have come from 

an intrinsically increasing population rather than an intrinsically decreasing population. Note 

that by chance, increasing time series can be observed from populations whose dynamics are 

intrinsically decreasing. However, for this time series, the observed rate of increase is high and 

the year-to-year variability is low. Such combinations are much more likely to be observed in 

intrinsically increasing populations. The data from the North Puget Sound plus South SOG

(Figure 67), South/Central Puget Sound (Figure 68), Strait of Juan de Fuca (Figure 69), and 

Squaxin Pass (Figure 70) subpopulations are more equivocal. The posterior probability surface 

is split between λ > 1 and λ < 1 indicating that the data are equivocal on whether the 

subpopulations are intrinsically decreasing or increasing. The point estimates should be viewed 

with caution for these subpopulations. For example, although λ for the South/Central Puget 

Sound subpopulation is high, these could have been produced by an intrinsically decreasing 

population; the data support for λ > 1 is only approximately four times higher than for λ < 1. 

Finally, for the Cherry Point population (Figure 46), the data support is very high that this is 

from an intrinsically declining population. The data observed are much more likely to have been 

produced by an intrinsically declining population rather than an intrinsically increasing one. 

Schweigert (1986, p. 150) suggested that the unrestricted reduction fishery that ended in 

1967 likely eliminated many “of the smaller and less productive resident stock[s]” in British 

Columbia. Likewise, Wallace (2002, p. 25) referring to the British Columbia portion of the 

Strait of Georgia, stated that, “during the period of over-exploitation [prior to 1967], numerous 

resident meta-populations [of Pacific herring] were depleted and have failed to return.” Wallace 

(2002, p. 26) also suggested that “the loss of numerous small resident stocks has likely had 

135
Table 15. Pacific herring spawner biomass (metric tons) estimates for proposed subpopulations within 

the Georgia Basin DPS from 1973 to 2004. Data from WDFWa

 and DFO.b See Figure 55 for

“subpopulation” boundaries. 

Year 

Bute 

Inlet 

North 

SOG 

Eastern 

SOG 

Inlets 

North PS 

+ South 

SOG 

Strait 

of Juan 

de 

Fuca 

Cherry 

Point 

South/ 

Central 

Puget 

Sound 

Squaxin 

Pass 

DPS 

total 

1973 400 11,516 232 5,214 11,767 29,129 

1974 465 27,928 452 12,327 8,630 49,802 

1975 741 36,875 1,738 10,552 5,890 1,058 270 57,124 

1976 379 32,520 792 11,919 675 8,699 4,369 1,940 61,293 

1977 388 48,485 275 7,073 1,435 7,984 5,737 18 71,395 

1978 163 41,359 33 8,786 1,193 8,018 3,730 53 63,334 

1979 242 25,313 0 12,007 800 7,296 4,523 124 50,305 

1980 496 35,525 418 8,472 3,264 7,023 6,695 620 62,513 

1981 422 37,317 326 10,257 2,785 5,642 4,305 700 61,755 

1982 384 40,010 155 3,525 2,137 4,449 5,535 56,195 

1983 284 20,117 0 5,155 2,517 7,315 5,774 41,162 

1984 14,436 0 5,035 2,880 5,353 6,277 33,981 

1985 18,536 0 7,938 1,329 5,225 6,082 39,110 

1986 255 32,538 0 8,032 1,633 5,145 5,526 53,127 

1987 136 26,345 136 5,766 1,445 2,702 7,570 44,100 

1988 43,076 9,756 774 3,903 5,221 62,730 

1989 37,971 7,890 1,332 3,398 5,507 56,098 

1990 575 44,848 13,838 776 4,266 5,879 513 70,695 

1991 856 43,530 7,660 1,136 3,957 4,518 855 62,511 

1992 575 50,215 23 12,162 679 3,465 3,527 699 71,345 

1993 648 68,058 10,311 776 4,165 4,655 541 89,154 

1994 102 50,717 9,901 380 5,429 4,853 204 71,588 

1995 226 45,421 6,875 500 3,422 7,342 142 63,928 

1996 105 53,849 109 2,906 841 2,685 5,260 339 66,095 

1997 146 51,431 265 10,071 324 1,428 5,833 135 69,633 

1998 63,535 3,716 103 1,199 6,104 62 74,718 

1999 134 57,013 214 8,412 598 1,148 9,375 430 77,324 

2000 159 59,461 30 5,449 269 733 8,605 337 75,043 

2001 199 63,326 817 8,618 209 1,126 10,125 1,449 85,868 

2002 93 91,074 10,626 253 1,207 9,344 2,858 115,453 

2003 285 95,029 18,149 228 1,461 8,086 1,997 125,234 

2004 350 97,557 8,659 249 1,573 7,062 751 116,201 a K. Stick, Washington Dept. Fish and Wildlife, La Conner, WA. Pers. commun., October 2004. 

b

 D. Hay and J. Schweigert, Dept. Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC, Canada. 

Pers. commun., December 2004. 

136
54 See footnote 5. 55 See footnote 36. 56 See footnote 5. 57 See footnote 36. 

0

2000

4000

6000

8000

10000

12000

14000

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (metric tons)

Figure 56. Cherry Point Pacific herring spawner biomass (metric tons) from 1973 to 2004. Data from

WDFW54 and DFO.55

0

500

1000

1500

2000

2500

3000

3500

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (

metric to

ns)

Figure 57. Strait of Juan de Fuca Pacific herring spawner biomass (metric tons) from 1973 to 2004. Data 

from WDFW56 and DFO.57

137
58 See footnote 5. 59 See footnote 36. 60 See footnote 5. 61 See footnote 36. 

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900.0

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (metric tons)

Figure 58. Bute Inlet Pacific herring spawner biomass (metric tons) from 1973 to 2004. Data from

WDFW58 and DFO.59

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (metric tons)

Figure 59. Eastern Strait of Georgia Inlets Pacific herring spawner biomass (metric tons) from 1973 to 

2004. Data from WDFW60 and DFO.61

138
62 See footnote 5. 63 See footnote 36. 64 See footnote 5. 65 See footnote 36. 

0

2000

4000

6000

8000

10000

12000

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (metric tons)

Figure 60. South/Central Puget Sound Pacific herring spawner biomass (metric tons) from 1973 to 2004. 

Data from WDFW62 and DFO.63

0

500

1000

1500

2000

2500

3000

3500

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (

metric tons)

Figure 61. Squaxin Pass Pacific herring spawner biomass (metric tons) from 1973 to 2004. Data from

WDFW64 and DFO.65

139
66 See footnote 5. 67 See footnote 36. 68 See footnote 5. 69 See footnote 36. 

0

20000

40000

60000

80000

100000

120000

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (

metric tons)

Figure 62. North Strait of Georgia Pacific herring spawner biomass (metric tons) from 1973 to 2004. 

Data from WDFW66 and DFO.67

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

1970 1975 1980 1985 1990 1995 2000 2005

Year

Biomass (metric tons)

Figure 63. North Puget Sound and South Strait of Georgia Pacific herring spawner biomass (metric tons) 

from 1973 to 2004. Data from WDFW68 and DFO.69

140
0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

North

SOG

North PS

+ South

SOG

Bute Inlet Eastern

SOG

Inlets

Squaxin

Pass

South /

Central

PS

Strait of

Juan de

Fuca

Cherry

Point 

Georgia

Basin

DPS

L

ong term abund

ance tren

d

Figure 64. Pacific herring long-term abundance trends (1973–2004) and associated 95% confidence 

limits for the Georgia Basin DPS and proposed subpopulations in the Georgia Basin DPS. 

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

1.50

1.60

North

SOG

North PS

+ South

SOG

Bute Inlet Eastern

SOG

Inlets

Squaxin

Pass

South /

Central

PS

Strait of

Juan de

Fuca

Cherry

Point 

Georgia

Basin

DPS

Short term abundance tren

d

Figure 65. Pacific herring short-term abundance trends (1990–2004) and associated 95% confidence 

limits for the Georgia Basin DPS and proposed subpopulations in the Georgia Basin DPS. 

141
Table 16. Estimates of long- and short-term trends and their 95% confidence intervals for proposed 

subpopulations of Pacific herring in the Georgia Basin Pacific herring DPS. 

DPS subpopulations Data years LT Trend (CI) 

ST Trend (CI) 

(1990-2004) 

Bute Inlet 1973–2004 0.97 (0.95–0.99) 0.92 (0.84–1.01) 

North SOG 1973–2004 1.04 (1.03–1.05) 1.05 (1.03–1.07) 

Eastern SOG Inlets 1973–2004 0.89 (0.80–0.99) 1.10 (0.79–1.55) 

North PS + South SOG 1973–2004* 1.00 (0.98–1.02) 1.00 (0.94–1.06) 

Cherry Point 1973–2004 0.93 (0.92–0.94) 0.89 (0.85–0.94) 

South / Central Puget Sound 1975–2004* 1.03 (1.10–1.04) 1.06 (1.03–1.08) 

Squaxin Pass 1975–2004 1.05 (0.99–1.11) 1.08 (0.94–1.23) 

Strait of Juan de Fuca 1976–2004* 0.92 (0.90–0.94) 0.90 (0.84–0.95) 

* Missing several years of biomass estimates for some subunits. 

far-reaching ecological consequences” in the Strait of Georgia. Hay and McCarter (1999, 

2004b) have documented the recent geographic concentration of spawning in the northern SOG 

and contraction of spawn timing in the SOG in general. In particular, there are fewer early 

spawnings in the SOG than in previous decades (Hay and McCarter 1999, 2004b). Despite the 

suspected reduction in nonmigratory Pacific herring stocks and the reduction in spawning 

distribution in the SOG, the overall level of abundance in the SOG has reached near record levels 

in recent years (Hay and McCarter 1999, Wallace 2002). 

The length of coastline receiving spawn deposition (spawn length) since 1940 for 

subpopulations of the DPS in British Columbia, and since 1972 for all of the DPS, is illustrated 

in Figure 71. It is recognized that comparison of annual spawn length records over wide 

geographic areas can be misleading, since spawning at different locations can vary in width and 

intensity (Hay and Kronlund 1987). In particular, spawn width and intensity can vary 

geographically due to topographical differences in spawn habitat (i.e., wide mudflats versus 

steep-sided inlets), changes in survey methods, shifts in spawn location, and real changes in 

spawner abundance (Hay and Kronlund 1987). However, this metric is one of the few indices 

that is available for all portions of the DPS and may therefore be a crude estimator of widespread 

trends. With the above caveats in mind, Figure 71 shows that the overall spawn length within 

the DPS has been relatively steady or increasing over time. With the exceptions of the Eastern 

SOG Inlets and Cherry Point subpopulations, spawn length in the individual subpopulations has 

also been relatively steady or increasing over time. 

IUCN Categories 

Results of application of the IUCN decline criteria to possible subpopulations within the 

Georgia Basin Pacific herring DPS are presented in Table 14. Over the past three generations 

(= 15 years), overall biomass of the Georgia Basin Pacific herring DPS has increased 

approximately 107% while the Cherry Point population and the proposed Strait of Juan de Fuca 

and Bute Inlet subpopulations have declined 54%, 81%, and 25%, respectively. Under the IUCN 

decline criteria, a reduction in population size of this magnitude “where the reduction or its 

causes may not have ceased or may not be understood or may not be reversible” (IUCN 2004, 

p. 10) would place Cherry Point in the “Endangered” category, Strait of Juan de Fuca in the 

“Critically Endangered” category, and Bute Inlet in the “Near Threatened” category. The other 

142
0.6 0.8 1 1.2 1.4

0

5

10

15

Lambda value

Pro

b

a

bility

d

e

n

sity

fu

n

ctio

n

of la

m

b

d

a

0 0.2 0.4 0.6 0.8 1

0

50

100

Probability of 95% decline in 10 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

5

10

Probability of 95% decline in 20 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0.8

1

1.2

1.4

1.6

Probability of 95% decline in 50 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

Figure 66. Lambda estimates for the North SOG Pacific herring subpopulation and the posterior 

probability that the subpopulation experiences a 95% decline in biomass within the next 10, 20, 

or 50 years. 

143
0.6 0.8 1 1.2 1.4

0

2

4

6

8

Lambda value

Pro

b

a

bility

d

e

n

sity

fu

n

ctio

n

of la

m

b

d

a

0 0.2 0.4 0.6 0.8 1

0

10

20

30

Probability of 95% decline in 10 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

2

4

6

Probability of 95% decline in 20 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0.6

0.8

1

1.2

1.4

Probability of 95% decline in 50 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

Figure 67. Lambda estimates for the North Puget Sound plus South SOG Pacific herring subpopulation 

and the posterior probability that the subpopulation experiences a 95% decline in biomass within 

the next 10, 20, or 50 years. 

144
0.6 0.8 1 1.2 1.4

0

2

4

6

Lambda value

Pro

b

a

bility

d

e

n

sity

fu

n

ctio

n

of la

m

b

d

a

0 0.2 0.4 0.6 0.8 1

0

5

10

15

Probability of 95% decline in 10 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

1

2

3

4

Probability of 95% decline in 20 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

1

2

3

Probability of 95% decline in 50 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

Figure 68. Lambda estimates for the South/Central Puget Sound Pacific herring subpopulation and the 

posterior probability that the subpopulation experiences a 95% decline in biomass within the next 

10, 20, or 50 years. 

145
0.6 0.8 1 1.2 1.4

0

2

4

6

Lambda value

Pro

b

a

bility

d

e

n

sity

fu

n

ctio

n

of la

m

b

d

a

0 0.2 0.4 0.6 0.8 1

0

5

10

15

Probability of 95% decline in 10 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

1

2

3

Probability of 95% decline in 20 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

0 0.2 0.4 0.6 0.8 1

0

1

2

3

Probability of 95% decline in 50 yrs

P

o

sterior pro

b

a

bility

d

e

n

sity

Figure 69. Lambda estimates for the Strait of Juan de Fuca Pacific herring subpopulation and the 

posterior probability that the subpopulation experiences a 95% decline in biomass within the next 

10, 20, or 50 years. 

146
Figure 70. Lambda estimates for the Squaxin Pass Pacific herring subpopulation and the posterior 

probability that the subpopulation experiences a 95% decline in biomass within the next 10, 20, 

or 50 years. 

147 
Spawn length (km) 

450 400 350 300 250 200 150 100 

50 

0 

Bute Inlet Squaxin Pass Cherry Point South/Central Puget Sound Strait of Juan de Fuca North PS/South SOG Eastern SOG Inlets North SOG 

1940

1942

1944

1946

1948

1950

1952

1954

1956

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

Year 

Figure 71. Kilometers of shoreline receiving Pacific herring spawn deposition in proposed subpopulations of the Georgia B

DPS (1940–2004). Washington State data series begins in 1972. Data from WDFW70 and DFO.71 

70 See footnote 5. 71 See footnote 36. 

148
five proposed subpopulations, comprising the vast bulk of the DPS, have increased in abundance 

over the past three generations (Table 14) and would be classified in the IUCN “Least Concern” 

category. 

149
Conclusions: Risk Assessment 

The BRT has concluded that the Georgia Basin Pacific herring DPS is not at risk of 

extinction in all or a significant portion of its range, nor likely to become so in the foreseeable 

future. Details about how the BRT reached this conclusion are summarized below. 

Available information (genetics, life history, tagging studies, etc.) suggests that 

population structure of Pacific herring roughly conforms to the classical concept of a 

metapopulation, in which local subpopulations are linked demographically by at least episodic 

migration, and extinction and recolonization of local subpopulations are common over ecological 

time frames. In this type of system, at any given point in time some local subpopulations are 

expected to be increasing and some declining, and some suitable habitat patches are expected to 

be uninhabited. 

Available information suggests that the Georgia Basin DPS of Pacific herring does not 

differ substantially in general features of biology from Pacific herring in other areas. Therefore, 

the BRT concluded that, as a reasonable approximation, the classical metapopulation model 

provides a framework for assessing extinction risk of the DPS. Under this framework, the fact 

that some local subpopulations are declining is not by itself cause for concern about the longterm viability of the DPS. Rather, the key question becomes, “Have recent factors, either natural 

or human-mediated, disrupted the functioning of the metapopulation to such an extent that its 

long-term viability is compromised?” This question could also be rephrased as: “Is the DPS at 

risk in a significant portion of its range, such that loss of the at-risk components would pose a 

substantial risk to long-term viability of the DPS?” 

To make this question more operational, the BRT considered the related question, “Are 

subpopulation declines more pervasive and more pronounced than we would expect to find in a 

healthy metapopulation?” To evaluate this last question, the BRT considered trends in eight 

different areas of the DPS, roughly defined on the basis of geography, life history, and genetics 

(Cherry Point, Squaxin Pass, South/Central Puget Sound, Strait of Juan de Fuca, Bute Inlet, 

Eastern SOG inlets, Northern SOG, and North Puget Sound plus Southern SOG). Overall 

abundance is declining within some of these areas and increasing in others (see Tables 14 and 

15, Figures 56–65). Ideally, one would like to be able to compare the current data with what 

might be obtained from taking a random series of historical “snapshots” from a healthy DPS, as 

this would provide a baseline against which to evaluate current patterns. Unfortunately, this is 

not feasible, at least at the present time. However, it is possible to compare patterns within the 

Georgia Basin DPS with data for Pacific herring in other areas. This comparison suggests that 

patterns of abundance and distribution within the Georgia Basin Pacific herring DPS appear to be 

fairly typical of what is seen in other Pacific herring populations throughout northwestern North 

America, including many relatively pristine areas in southeastern Alaska and British Columbia 

(Hay et al. 2001b). Furthermore, overall abundance of the DPS is at historically high levels, and 

the number of kilometers of coastline used by Pacific herring for spawning has also been 

150
increasing (Hay and McCarter 1999) (see Figure 71). Therefore, the BRT concluded that 

available evidence does not suggest unusual levels of risk to the DPS as a whole, nor to a 

significant part of the DPS. 

However, the BRT also identified reasons for concern about some local subpopulations 

within the DPS and some potential future developments that would increase risks to the DPS. 

First, metapopulation theory indicates that in source-sink systems (that is, when some areas 

[sources] regularly produce excess migrants that colonize habitat patches with negative net 

productivity [sinks]), the existence of sinks can buffer extinction risk of the entire 

metapopulation, compared to a scenario in which the sink areas cease to function at all. 

Furthermore, habitat patches that are sinks during one environmental regime can become sources 

if conditions change (and vice versa). Hilborn et al. (2003) recently provided a good empirical 

example of the importance of temporal changes in relative productivity of different populations 

of Bristol Bay sockeye salmon (O. nerka) in stabilizing long-term, overall abundance. 

Therefore, a scenario in which currently unproductive habitat is allowed to cease functioning 

altogether, or to permanently degrade to the point at which it cannot revert to good habitat during 

favorable environmental regimes, can impair the functioning of the entire metapopulation. 

Available evidence does not suggest that this factor has contributed significantly to the current 

patterns of subpopulation declines within the DPS. For example, some of the most depressed 

(perhaps even extirpated) subpopulations occur in eastern SOG inlets, areas that have relatively 

pristine habitat. In addition, at Cherry Point, where recent declines are a concern, the most 

intense Pacific herring spawn activity is concentrated in some of the most disturbed habitat—not 

the pattern that would be expected if habitat factors were impairing metapopulation function. 

Nevertheless, this issue warrants close monitoring in the future, as human population pressures 

are expected to increase in many areas used by the DPS. 

Second, the BRT recognized that the classical metapopulation concept does not perfectly 

fit the Georgia Basin Pacific herring DPS. The pattern of subpopulation structure in the DPS is 

more similar to the mixed structure metapopulation model of Harrison and Taylor (1997) than to 

Levins’ (1969, 1970) classical metapopulation. Although the DPS is characterized by high 

levels of homogeneity, the Cherry Point population and some subpopulations such as Squaxin 

Pass are relatively more distinctive, based on spawn timing, growth rate, contaminant profiles, 

and genetic differences. And as noted above, the BRT concluded that Cherry Point Pacific 

herring meets the DPS criteria to be considered a “discrete” population. These differences are 

not of a magnitude that suggests long-term evolutionary divergence, but it is possible that 

demographic linkages between these and other subpopulations in the DPS are weak enough that 

they are largely demographically independent on ecological time scales. If this is the case, and if 

these subpopulations were lost, recolonization might take longer than it would for areas that are 

part of a classical metapopulation. Still, the BRT did not feel that current risks to these areas 

represent risks to a significant portion of the range of the DPS as a whole. Cherry Point Pacific 

herring are characterized by late mean spawn timing, but this timing is not temporally 

discontinuous and falls within the tail of the distribution for the DPS as a whole, and 

subpopulations with similar spawn timing occur in other geographic areas, beyond the 

boundaries of the DPS. The Cherry Point Pacific herring population represents only one of about 

40 recognized assessment regions or stocks within the DPS, although historically it may have 

been one of the largest populations in the central part of the DPS. At its peak several decades 

ago, Cherry Point Pacific herring represented perhaps about 11% of the biomass of the DPS as a 

151
whole, but this proportion is speculative and not necessarily indicative of historical conditions,

because at that time many of the larger subpopulations in the DPS were severely depressed due 

to overharvesting and poor recruitment conditions. 

If Cherry Point and Squaxin Pass are largely independent demographically, they would 

correspond to independent populations under the criteria established in the viable salmonid 

populations framework (McElhany et al. 2000). Therefore it is useful to briefly review the ESA 

listing status of Pacific salmon DPSs comparable in size and complexity to the Georgia Basin 

Pacific herring DPS. Most Pacific salmon DPSs cover roughly comparable geographic areas 

(e.g., Pacific salmon DPSs have been identified at the level of Puget Sound, Georgia Basin, 

Snake River Basin, and California Central Valley) and include a substantial number (typically 

20–40) of demographically independent populations/stocks. Thus the Georgia Basin Pacific 

herring DPS, with perhaps a few demographically independent populations interacting with a 

larger metapopulation, shows less demographic/genetic structure than most Pacific salmon DPSs. 

Many Pacific salmon DPSs include populations with considerable life history/ecological/genetic 

diversity, on a scale as large or (in most cases) larger than found within the Georgia Basin 

Pacific herring DPS. Conservation of this diversity has been given important consideration in 

both ESA listing determinations and in ongoing recovery planning efforts (Ruckelshaus et al. in 

press, Interior Columbia Basin TRT 2003, Myers et al. 2006, Lawson et al. 2004, Lindley et al. 

2004), and about half of the more than 50 Pacific salmon and steelhead DPSs recognized in the 

lower 48 states are now listed under the ESA. The status of these listed DPSs has recently been 

reviewed and updated (Good et al. 2005), and several relevant points emerge from a comparison 

of these results with data for the Pacific herring DPS: 

1. In no listed Pacific salmon DPS is abundance of natural fish anywhere near historic 

levels. 

2. No Pacific salmon DPS is listed based on declines in only a small fraction of the 

component populations. 

3. Although life history diversity is considered very important, risks to one or two 

distinctive populations do not necessarily result in a conclusion of risk to the entire DPS. 

For example, the Klamath Mountains Province steelhead and upper Klamath River 

Chinook salmon DPSs are not listed, in spite of concerns for the status of certain life 

history types (summer steelhead and spring Chinook salmon, respectively). 

4. Although risk factors for Pacific salmon are many and complex, in all listed DPSs loss or 

degradation of habitat was identified as a factor contributing to population declines. In 

many cases, it has been possible to roughly quantify the changes in Pacific salmon habitat 

compared to historic conditions, which provides a basis for determining how far from the 

historic (presumably viable) template current situations are. In contrast, no specific risk 

factor has been identified as the primary cause of decline in the portions of the Georgia 

Basin Pacific herring DPS that are of most concern. This makes it difficult to determine 

whether the current population trajectories are out of the range of historic patterns. 

Therefore, the BRT conclusion that the Georgia Basin Pacific herring DPS is not at risk in all or 

a significant portion of its range appears to be consistent with how previous BRTs have 

considered risk for complex DPSs of Pacific salmon. 

152
Finally, the BRT noted that Pacific herring play important roles in the Georgia Basin 

ecosystem. If the fundamental biological processes necessary for Pacific herring were to be 

disrupted in the future, such that the metapopulation ceased to function effectively, the 

consequences for other species could be substantial. Although these consequences are difficult 

to predict, it is worth noting that Pacific herring are important forage fish for both Pacific salmon 

and killer whales, so collapse of the Pacific herring DPS could have serious negative effects on 

these other protected species. 

153
154
Glossary 

Allele. An alternative form of a gene that can occur at the same location (locus) on homologous 

(paired) chromosomes. A population can have many alleles for a particular locus, but an 

individual can carry no more than two alleles at a diploid locus. 

Allozymes. Alternative forms of an enzyme that have the same function, are produced by 

different alleles, and are often detected by protein electrophoresis. 

Anthropogenic. Caused or produced by human action. 

BTEX. Acronym for benzene, toluene, ethylbenzene, and xylene. Volatile organic compounds 

found in crude oil and other petroleum hydrocarbons. 

BRT (Biological Review Team). The team of scientists who evaluate scientific information 

considered in the National Marine Fisheries Service status reviews. 

CWT (coded-wire tag). A small piece of wire, marked with a binary code, which is normally 

inserted into the nasal cartilage of juvenile fish. Because the tag is not externally visible, the 

adipose fin of coded wire-tagged fish is removed to indicate the presence of the tag. Groups 

of thousands to hundreds of thousands of fish are marked with the same code number to 

indicate stock, place of origin, or other distinguishing traits for production releases and

experimental groups. 

Comanagers. Federal, state, and tribal agencies that cooperatively manage groundfish in the 

Pacific Northwest. 

dB (decibel). The decibel is a measure of sound level and is a subunit of a larger unit called the 

bel. As originally used, the bel represented the power ratio of 10 to 1 between the strength or 

intensity of two sounds, and was named after Alexander Graham Bell. 

DDT (1,1,1-trichloro-2,2-bis-[p-chlorophenyl] ethane). Persistent contaminants of aquatic 

sediments and biota. Commercial formulations of DDTs are mixtures of individual 

chlorinated biphenyls. Prior to the 1975 congressional ban on DDT manufacture, DDTs 

were commonly used as pesticides. 

Depensation. Depensation occurs when a decrease in abundance leads to reduced survival or 

production of offspring due either to increased predation per offspring, given constant 

predation pressure, or to the reduced likelihood of finding a mate (Allee effect). 

DPS (distinct population segment). A population, or group of populations, of a vertebrate 

organism that is “discrete” from other populations and “significant” to the biological species 

as a whole. 

155
DNA (deoxyribonucleic acid). DNA is a complex molecule that carries an organism’s heritable 

information. DNA consists of a polysugar-phosphate backbone from which the bases 

(nucleotides) project. DNA forms a double helix that is held together by hydrogen bonds 

between specific base pairs (thymine to adenine, guanine to cytosine). Each strand in the 

double helix is complementary to its partner strand in terms of its base sequence. The two 

types of DNA commonly used to examine genetic variation are mitochondrial DNA

(mtDNA), a circular molecule that is maternally inherited, and nuclear DNA, which is 

organized into a set of chromosomes (see also allele). 

dwt (dead weight tons). The total lifting capacity of a ship expressed in tons of 2,240 lbs. It is 

the difference between the displacement light and the displacement loaded. 

Endangered species. A species in danger of extinction throughout all or a significant portion of 

its range. 

ESA. U.S. Endangered Species Act. 

ESU (evolutionarily significant unit). An ESU represents a distinct population segment of 

Pacific salmon under the Endangered Species Act that 1) is substantially reproductively 

isolated from conspecific populations, and 2) represents an important component of the 

evolutionary legacy of the species. 

Euryhaline. Refers to organisms that tolerate a wide range of salinities.

EVOS. Exxon Valdez oil spill. Refers to the largest oil spill in U.S. history, which occurred in 

Prince William Sound, Alaska, on 24 March 1989 when the oil tanker Exxon Valdez ran 

aground on Bligh Reef. 

FACs (fluorescent aromatic compounds). Fish possess a significant capability, primarily in 

the liver, to readily metabolize PAHs and related aromatic compounds to more polar products 

(metabolites) that pass into the bile for excretion. These compounds are not detectable in 

customary PAH analytical procedures, but are determined by their fluorescence, most of 

which is retained during the metabolic transformations. 

Genetic distance. A quantitative measure of genetic difference between a pair of samples. 

Genetic drift. The occurrence of random changes in the gene frequencies of populations. 

Georgia Basin. The semienclosed marine basin comprised of the Strait of Georgia, Puget 

Sound, and the Juan de Fuca Strait, together with the lands that drain into these marine 

waters. 

Haplotype. The collective genotype of a number of closely linked loci; the constellation of

alleles present at a particular region of genomic or mitochondrial DNA. 

IUCN. International Union for the Conservation of Nature and Natural Resources. In 1990 the 

name was shortened to IUCN -The World Conservation Union. 

156
Least squares means. Means that have been corrected for imbalances in other variables are 

called least squares means (also known as adjusted means). 

LC50. The “lethal concentration” of a chemical or substance that kills 50% of the test organisms 

in a given time period, normally 96 hours for aquatic organisms. 

Locus (pl. loci). The site on a chromosome where a gene is found; often used more or less 

synonymously with gene (cf allozymes). 

Meristic trait. A discretely varying and countable trait (e.g., number of fin rays or basibranchial 

teeth). 

Metapopulation. A metapopulation is an assembly of closely related subpopulations (usually 

spatially fragmented) that were established by colonists, survive for a while, send out 

migrants, and eventually disappear. The persistence of a subpopulation depends on the rate 

of colonization successfully balancing the local extinction rate. 

Microsatellite DNA. A class of repetitive DNA. Microsatellites are simple sequence repeats 

one to eight nucleotides in length. For example, the repeat unit can be simply “CA”, and 

might exist in a tandem array (CACACACACA) 50 or more repeat units in length. The 

number of repeats in an array can be highly polymorphic. 

Mitochondrial DNA. The DNA genome contained within mitochondria and encoding a small 

subset of mitochondrial functions; mtDNA is typically circular and 15–20 kilobases in size, 

containing little noncoding information between genes. 

MLLW (mean lower low water). A tidal measure. The average of the lower low water height 

of each tidal day observed. 

Morphometric trait. A discretely varying trait related to the size and shape of landmarks from

whole organs or organisms analyzed by appropriately invariant biometric methods in order to 

answer biological questions. 

NWFSC. Northwest Fisheries Science Center. 

Otolith. Crystalline calcium carbonate structures within the inner ear of fish. These structures 

have distinctive shapes, sizes, and internal and surface features that can be used for age 

determination and species identification. 

ppb (parts per billion). A unit of chemical concentration. 

ppm (parts per million). A unit of chemical concentration. 

PDO (Pacific Decadal Oscillation). A pattern of Pacific climate variability persisting for 20–30 

years, in contrast to typical El Niño climate events, which persist for 6–18 months. The 

climatic indicators of the PDO are most visible in the North Pacific region. 

157
Phenotype. The appearance (or other measurable characteristic) of an organism that results 

from interaction of the genotype and environment. 

PCB (polychlorinated biphenyl). Persistent contaminants of aquatic sediments and biota that 

are very widespread. Commercial formulations of PCBs are mixtures of individual 

chlorinated biphenyls (congeners) varying according to the numbers of chlorines and their 

ring positions on the biphenyl. Prior to the 1975 congressional ban on PCB manufacture, 

various mixtures of some 209 individual PCBs were used extensively in electrical 

transformers, capacitors, paints, waxes, inks, dust control agents, paper, and pesticides. 

PAH (polycyclic aromatic hydrocarbon). The PAHs are widely distributed throughout the 

marine environment and commonly occur in sediments in urban coastal and estuarine areas. 

Sources include crude oil, petroleum products, and residues from combustion of fossil fuels. 

They are composed of fused benzene rings, with or without alkyl substituents (e.g., methyl 

groups). 

Population. A group of individuals of a species living in a certain area that maintain some

degree of reproductive isolation. 

Puget Sound. A coastal fjord-like estuarine inlet of the Pacific Ocean located in northwest 

Washington State between the Cascade and Olympic mountains and covering an area of over 

9,000 km2 including 3,700 km of coastline. 

Reduction fishery. Commercial fisheries where the harvested fish are processed (reduced) into 

low-value products, such as fish meal and oil. 

Species. Biological: A small group of organisms formally recognized by the scientific 

community as distinct from other groups. Legal: Refers to joint policy of the USFWS and 

NMFS that considers a species as defined by the ESA to include biological species, 

subspecies, and DPSs. 

Standard length. Length in millimeters from the tip of the snout to the end of the silvery 

portion of the body. 

SOG (Strait of Georgia). The body of water separating the southern portion of Vancouver 

Island and the British Columbia mainland. The strait extends from Cortes Island and 

Desolation Sound in the north to the San Juan Islands in the south. 

Strait of Juan de Fuca. The body of water separating the southern portion of Vancouver Island 

and the Olympic Peninsula in Washington. The strait extends from the Pacific Ocean east to 

the San Juan and Whidbey Islands. 

Threatened species. A species not presently in danger of extinction but likely to become so in 

the foreseeable future. 

TPAHs (Total PAHs). The summed total of all the individual PAHs detected in a sample. 

158
Trophic. Pertaining to nutrition. A trophic migration would be a movement of fish to a feeding 

area. 

VSP (viable salmonid population). An independent population of any Pacific salmonid (genus 

Oncorhynchus) that has a negligible risk of extinction due to threats from demographic 

variation, local environmental variation, and genetic diversity changes over a long time frame 

(McElhany et al. 2000). 

WDFW (Washington Department of Fish and Wildlife). Department that comanages certain 

fisheries in Washington State with WWTIT and other fisheries groups. The agency was 

formed in the early 1990s by combining the Washington Department of Fisheries and 

Washington Department of Wildlife. 

WWTIT (Western Washington Treaty Indian Tribes). An organization of Native American 

tribes with treaty fishing rights recognized by the United States. WWTIT comanages certain 

fisheries in western Washington in cooperation with WDFW and other fisheries groups. 

159
160
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PB2006-111431. 

Most NOAA Technical Memorandums NMFS-NWFSC are available online at the

Northwest Fisheries Science Center web site (http://www.nwfsc.noaa.gov).