NOAA Technical Memorandum NMFS-NWFSC-53 

Review of Potential Impacts


of Atlantic Salmon Culture


on Puget Sound Chinook Salmon


and Hood Canal


Summer-Run Chum Salmon


Evolutionarily Significant Units


June 2002 

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 

NMFS-F/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: 

Waknitz, F.W., T.J. Tynan, C.E. Nash, R.N. Iwamoto, 

and L.G. Rutter. 2002. Review of potential impacts 

of Atlantic salmon culture on Puget Sound chinook 

salmon and Hood Canal summer-run chum salmon 

evolutionarily significant units. U.S. Dept. Commer., 

NOAA Tech. Memo. NMFS-NWFSC-53, 83 p. 
1 

2 

3 

NOAA Technical Memorandum NMFS-NWFSC-53 

Review of Potential Impacts


of Atlantic Salmon Culture


on Puget Sound Chinook Salmon


and Hood Canal


Summer-Run Chum Salmon


Evolutionarily Significant Units


F. William Waknitz1, Tim J. Tynan3, 

Colin E. Nash2, Robert N. Iwamoto2

, 

and Larry G. Rutter3 

Northwest Fisheries Science Center


Conservation Biology Division


2725 Montlake Boulevard East


Seattle, Washington 98112


Northwest Fisheries Science Center


Resource Enhancement and Utilization Technologies Division


2725 Montlake Boulevard East


Seattle, Washington 98112


NMFS Northwest Regional Office


Sustainable Fisheries Division


510 Desmond Drive Southwest


Lacey, Washington 98503


June 2002 

U.S. DEPARTMENT OF COMMERCE 

Donald L. Evans, Secretary 

National Oceanic and Atmospheric Administration 

Vice Admiral Conrad C. Lautenbacher, Jr. USN (Ret), Administrator 

National Marine Fisheries Service 

William T. Hogarth, Administrator for Fisheries 
ii 

Most NOAA Technical Memorandums NMFS-NWFSC are 

available on-line 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)

iii

TABLE OF CONTENTS 

LIST OF TABLES......................................................................................................................................vii 

EXECUTIVE SUMMARY .........................................................................................................................ix 

ACKNOWLEDGMENTS ...........................................................................................................................xi 

INTRODUCTION ........................................................................................................................................1 

Intent of Present Document ......................................................................................................................1 

Concerns Regarding Salmon Farming in Puget Sound ............................................................................3 

Scope of Literature Review ......................................................................................................................3 

Previous Investigations of Salmon Farming in the Pacific Northwest .....................................................4 

ORIGIN OF ATLANTIC SALMON STOCKS IN PUGET SOUND..........................................................7 

POTENTIAL GENETIC IMPACTS OF ATLANTIC SALMON CULTURE IN THE PUGET SOUND 

CHINOOK AND HOOD CANAL SUMMER-RUN CHUM SALMON ESUS ..........................................9 

Potential Genetic Interactions of Artificially Propagated Pacific and Atlantic Salmon...........................9 

Hybridization between Atlantic and Pacific Salmon................................................................................9 

Potential Genetic Compatibility ...........................................................................................................9 

Potential Contribution from Precocious Male Atlantic Salmon.........................................................12 

Hybridization between Atlantic Salmon and Brown Trout................................................................13 

Hybridization among Pacific Salmon.................................................................................................14 

Genetic Dilution and Alteration of the Wild Salmon Gene Pool ...........................................................14 

Potential Impact of Transgenic Atlantic Salmon....................................................................................15 

POTENTIAL FOR COLONIZATION OF PUGET SOUND CHINOOK AND HOOD CANAL 

SUMMER-RUN CHUM SALMON ESUS BY ATLANTIC SALMON...................................................17 

Success of Atlantic Salmon Introductions Worldwide ...........................................................................17

Success of Atlantic Salmon Introductions in the United States..............................................................17 

Success of Atlantic Salmon Introductions in the Pacific Northwest ......................................................17 

Possible Reasons for the Failure of Atlantic Salmon Introductions.......................................................20 

Primitive Hatchery Methods ..............................................................................................................20 

Pristine Habitats and Healthy Pacific Salmon Populations................................................................20 

Incompatible Biological Characteristics of Introduced Atlantic Salmon...........................................20 

POTENTIAL FOR DISEASE TRANSMISSION OR ADVERSE DISEASE IMPACTS BETWEEN 

ATLANTIC SALMON AND PACIFIC SALMON IN WASHINGTON..................................................23 

Diseases of Salmon and Trout in Hatcheries..........................................................................................23 

Disease Therapy .....................................................................................................................................25 

Concerns Regarding Treatment of Diseases in Salmon Rearing Facilities........................................25 

Chemotherapeutants Registered for Use in the United States............................................................26 

Amount of Antibiotics Used in Fish Culture Facilities......................................................................26 

Disease Interactions between Hatchery and Wild Salmon and Trout.....................................................27 

Transmissions of Disease from Hatchery to Wild Salmon ................................................................27 

Diseases of Atlantic Salmon in the Pacific Northwest.......................................................................28 

Potential for Disease Transmission from Atlantic Salmon to Pacific Salmon...................................28 

The Scale of Artificial Propagation of Salmon in the Pacific Northwest and Disease Transmission 

Potential..............................................................................................................................................28 

Disease Control Policies in Washington and the United States.........................................................29 

POTENTIAL ECOLOGICAL IMPACTS OF ATLANTIC SALMON IN THE PACIFIC 

NORTHWEST............................................................................................................................................31 

Impacts of Cultured Atlantic Salmon on Wild Atlantic Salmon ............................................................31 

Impacts of Cultured Pacific Salmon on Wild Pacific Salmon................................................................31 

Ecological Interactions between Atlantic Salmon and Pacific Salmon..................................................32 
iv

Behavioral Interactions ......................................................................................................................32 

Predation by Atlantic Salmon ............................................................................................................32 

Predation by Introduced Brown Trout................................................................................................33 

Ecological Interactions between Cultured Pacific Salmon and Wild Pacific Salmon............................34 

Chinook Salmon.................................................................................................................................34 

Chum Salmon.....................................................................................................................................35 

Steelhead Trout ..................................................................................................................................35 

Coho Salmon......................................................................................................................................35 

Pacific Trout.......................................................................................................................................36 

ADVERSE IMPACTS OF NONINDIGENOUS FISH INTRODUCTIONS.............................................39 

MANAGEMENT OF NONINDIGENOUS FISH IN WASHINGTON.....................................................41 

SCALE OF ARTIFICIAL PROPAGATION OF PACIFIC SALMON IN THE PACIFIC 

NORTHWEST............................................................................................................................................43 

Number of Artificially Propagated Pacific Salmon Released Each Year...............................................43 

Survival of Artificially Propagated Pacific Salmon ...............................................................................43 

Comparison of Numbers of Artificially Propagated Atlantic Salmon and Pacific Salmon in the Pacific 

Northwest ...............................................................................................................................................44 

POTENTIAL IMPACT OF SUCCESSFULLY REPRODUCING ATLANTIC SALMON IN PUGET 

SOUND.......................................................................................................................................................47 

Number of Naturally Produced Juvenile Atlantic Salmon that Would Approximate Impacts from 

Pacific Salmon Hatchery Programs in Puget Sound...............................................................................47 

Number of Naturally Produced Juvenile Atlantic Salmon that Would Approximate Impacts from 

Pacific Salmon Hatchery Programs in the Green River .........................................................................47 

Number of Juvenile Atlantic Salmon Observed in the Pacific Northwest..............................................48 

OTHER EVALUATIONS OF POTENTIAL RISKS FROM CULTURED ATLANTIC SALMON IN 

PUGET SOUND CHINOOK SALMON AND HOOD CANAL SUMMER-RUN CHUM SALMON 

ESUS ...........................................................................................................................................................49 

Washington State Pollution Control Hearings Board.............................................................................49 

Washington Department of Fish and Wildlife Atlantic Salmon Management Perspective....................50 

NMFS Biological Status Reviews of West Coast Pacific Salmon Stocks..............................................50 

POTENTIAL IMPACTS OF SALMON FARMS IN PUGET SOUND ON ESSENTIAL FISH 

HABITAT...................................................................................................................................................51 

Water Column Impacts...........................................................................................................................51 

Comparison to Benthic Impacts of Other Activities in the Pacific Northwest.......................................52 

Sewage Treatment Plants...................................................................................................................52 

Fish Processing Plants........................................................................................................................52 

SCALE AND IMPACTS OF SIMILAR ACTIVITIES IN PUGET SOUND............................................55 

Scale of Salmon Farms and Other Aquaculture .....................................................................................55 

Salmon Farms.....................................................................................................................................55 

Oyster Farms......................................................................................................................................56 

Scale and Impacts of Marinas in Puget Sound .......................................................................................56 

Scale of Marina Development............................................................................................................56 

Environmental Impacts of Marinas....................................................................................................56 

ESSENTIAL FISH HABITAT AND THE MAGNUSON-STEVENS ACT.............................................59 

REGULATORY STRUCTURE FOR COMMERCIAL AQUACULTURE ENTERPRISES IN 

WASHINGTON AND PUGET SOUND ...................................................................................................61

Agencies Regulating Salmon Farming in Washington...........................................................................62 

State of Washington Agencies ...........................................................................................................62 

Federal Agencies................................................................................................................................64 

The Regulatory Structure for Public and Tribal Hatcheries in Washington...........................................64 
v

CONCLUSIONS REGARDING POTENTIAL IMPACTS OF ATLANTIC SALMON CULTURE IN 

PUGET SOUND.........................................................................................................................................65 

CITATIONS ...............................................................................................................................................67 
vi
vii

LIST OF TABLES 

Table 1. Percent survival to hatch from various Atlantic salmon x Pacific salmon crosses, or interspecific 

Pacific salmon x Pacific salmon crosses, using a small number of eggs (less than 500)...................11 

Table 2. Percent survival to hatch from various Atlantic salmon x Pacific salmon crosses, using a large 

number of eggs (more than 2,000). ....................................................................................................11 

Table 3. Number of juvenile Atlantic salmon observed in British Columbia freshwater areas, 

1996-2001. .........................................................................................................................................19 

Table 4. Facilities (% in state or agency) testing positive for various salmonid diseases (July 1988-June 

1993). .................................................................................................................................................24 

Table 5. Number (in millions) of salmon released or escaped by species and location along the West 

Coast of North America, 1980-1995. .................................................................................................30 

Table 6. Status of non-native fish introductions in the Pacific Northwest and their behavior relative to 

Pacific salmonids................................................................................................................................40 
viii
ix

EXECUTIVE SUMMARY 

This document examines the potential of Atlantic salmon farming in Puget Sound to 

impose adverse impacts on the Puget Sound chinook salmon (Oncorhynchus tshawytscha) and 

Hood Canal summer-run chum salmon (O. keta) evolutionarily significant units (ESUs), both of 

which were listed as “threatened” under the federal Endangered Species Act (ESA) by the 

National Marine Fisheries Service (NMFS) in March 1999. The threatened status of these 

populations requires that all activities that may harm the fish or their critical habitat be limited 

such that they do not appreciably reduce the likelihood for recovery of the ESUs in the wild. 

Many of the activities that may lead to the take of listed salmon in Puget Sound, 

including the artificial propagation of salmonids in hatcheries and marine enclosures, will have 

effects that are incidental to otherwise lawful activities. Among such activities is the private 

culture of Atlantic salmon. This document presents the best scientific and commercial 

information available to evaluate the possible effects of salmon farming on listed chinook and 

summer-run chum salmon populations, and will provide the scientific basis for federal regulatory 

agency direction for the appropriate management of the industry in Puget Sound. 

Much of the available scientific information pertaining to salmon aquaculture was 

produced by NMFS in furtherance of its national mandate to advocate environmentally 

sustainable aquaculture through research, technology development, financial assistance, and 

regulatory programs. Locally, Washington State policies also recognize aquaculture as a 

legitimate and beneficial use of its coastal waters. By reason of NMFS’ concomitant 

responsibilities to conserve Pacific salmon species, especially those listed under the ESA, the 

agency has also collected, analyzed, and published a significant amount of scientific information 

relevant to the specific issue of Atlantic salmon impacts on federally listed Pacific salmon. After 

conducting several scientific reviews of Washington’s Atlantic salmon farming industry, 

including the present one, NMFS concluded that the operations can be managed to minimize 

risks to local salmon populations. In particular, NMFS found that Washington State regulation 

of the industry provides adequate protection to stocks of Pacific salmon listed under the ESA. 

Nonetheless, there are legitimate issues associated with hatchery-reared salmon and trout that 

end up in natural ecosystems, either by deliberate release or by escape from the rearing facility. 

Concerns regarding the artificial propagation of salmon and trout in the Pacific Northwest 

have been expressed numerous times in recent years, focused primarily on Pacific salmon 

hatcheries. However, concerns about the potential adverse impacts of private trout and Atlantic 

salmon culture in Washington have been expressed as well. Uncertainty about genetic and 

ecological interactions and the transmission of disease among Atlantic and Pacific salmon are the 

most commonly voiced concerns. 

It should be understood that this review does not intend to evaluate potential risks 

associated with Atlantic salmon farming anywhere in the world except Puget Sound, 

Washington. Also, social issues related to salmon farming in Puget Sound are not discussed. 

Much of the material presented here has been taken from previous NMFS evaluations of the risks 

of Atlantic salmon in Pacific coast states or from NMFS’ ESA-related status reviews of West 

Coast salmonids. 
x

The conclusions regarding the potential impacts of Atlantic salmon culture on the Puget 

Sound chinook salmon and Hood Canal summer-run chum salmon ESUs are based on three 

important assumptions. The first assumption is that the salmon farming industry in Puget Sound 

remains approximately the same size as currently or in the recent past. A significant expansion 

of the industry may increase risks and would require a reconsideration of some of the potential 

impacts discussed in this review. The second assumption is that salmon farms in Puget Sound 

continue to rear only Atlantic salmon. Should the local industry shift production to coho or 

chinook salmon or to steelhead (O. mykiss), the risks for hybridization, dilution of the gene pool, 

colonization, and competition for natural resources with wild salmonids will be greater than they 

are now with Atlantic salmon culture. Third, these conclusions assume that Atlantic salmon 

farmers in Washington continue to use only stocks presently in culture and that no new Atlantic 

salmon stocks are brought into the State. 

Based on these assumptions, this review arrives at the following risk assessment 

conclusions: It finds no risk for one parameter, low risk for several parameters, little risk for 

other parameters, and no parameters for which the potential impacts from Atlantic salmon farms 

in Puget Sound are considered to be serious or even moderate. 

The review finds no risk of adverse genetic interaction from transgenic salmon because 

there are currently no transgenic salmon being commercially cultured in Washington and there 

are no plans to do. 

For several parameters, the risks associated with escaped Atlantic salmon are low, in 

particular: 

• The expectation that Atlantic salmon will increase current disease incidence in wild and 

hatchery salmon is low. 

• The risk that escaped Atlantic salmon will compete with wild salmon for food or habitat is 

low, considering their well-known inability to succeed away from their historic range. 

• The risk that salmon farms will adversely impact Essential Fish Habitat is low, especially 

when compared to other commonly accepted activities that also occur in nearshore marine 

environments. 

For other parameters, there appears to be little risk associated with escaped Atlantic 

salmon, in particular: 

• There is little risk that escaped Atlantic salmon will hybridize with Pacific salmon. 

• There is little risk that Atlantic salmon will colonize habitats in the Puget Sound chinook 

salmon and Hood Canal summer-run chum salmon ESUs. 

• There is little risk that escaped Atlantic salmon will prey on Pacific salmon. 

• There is little risk that existing stocks of Atlantic salmon will be a vector for the introduction 

of an exotic pathogen into Washington State. 

• There is little risk that the development of antibiotic-resistant bacteria in net-pen salmon 

farms or Atlantic salmon freshwater hatcheries will impact native salmonids, as similar 

antibiotic resistance often observed in Pacific salmon hatcheries has not been shown to have 

a negative impact on wild salmon. 
xi

ACKNOWLEDGMENTS 

The authors thank the following individuals, who kindly provided information and 

assistance that was essential to the completion of this document: Donald Noakes and Andrew 

Thomson of the Department of Fisheries and Oceans Canada; Peter Granger and Kevin Bright of 

the Washington Fish Growers Association; Robert Kope and Lee Harrell of NMFS; Jim Parsons 

of Troutlodge, Inc.; Andy Appleby and Dave Seiler of the Washington Department of Fish and 

Wildlife; and Tim Wheeler of the Port of Seattle. 

The authors also give special thanks to the individuals who provided critical comments 

on draft versions of this document: Kevin Amos, Tom Good, Jeff Hard, Peter Kareiva, and 

Conrad Mahnken of NMFS; Reginald Reisenbichler of the U.S. Geological Survey; Donald 

Noakes, Trevor Evelyn, and Andrew Thomson of the Department of Fisheries and Oceans 

Canada; Mart Gross, University of Toronto; Ian Fleming, Oregon State University; Kenneth 

Brooks, Aquatic Environmental Sciences, Inc.; and Donald Campton, U.S. Fish and Wildlife 

Service. 

The conclusions and recommendations in this document are those of the authors and do 

not necessarily reflect the opinions of the reviewers. 
xii
INTRODUCTION 

In response to the depleted status of naturally produced chinook salmon (Oncorhynchus 

tshawytscha) and certain summer-run chum salmon (O. keta) in the Puget Sound region of 

Washington State, the National Marine Fisheries Service (NMFS) listed the populations as 

“threatened” under the U.S. Endangered Species Act (ESA) of 1973 in March 1999. The 

populations or evolutionarily significant units (ESUs) (Waples 1991) listed for protection under 

the provisions of the Act were the Puget Sound chinook salmon ESU and the Hood Canal 

summer-run chum salmon ESU. Subsequent to these listings, NMFS designated critical habitat 

necessary for the recovery of the populations to healthy levels. The Puget Sound chinook 

salmon ESU’s critical habitat generally includes all freshwater areas accessible to anadromous 

salmon in the Puget Sound region, as well as the marine waters of Puget Sound. Critical habitat 

for the Hood Canal summer-run chum salmon ESU is encompassed within the area designated 

for chinook salmon. 

Intent of Present Document 

The ESA-listing status of these populations as threatened requires that all activities that 

may harm the fish or their critical habitat be limited such that they do not appreciably reduce the 

likelihood for the survival and recovery of the ESUs in the wild. In particular, Section 9 of the 

ESA and federal regulations pursuant to Section 4(d) of the ESA prohibit the direct or incidental 

“take” of endangered and threatened salmon species, respectively, without special exemption 

from NMFS. “Take” is defined as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture 

or collect, or to attempt to engage in any such conduct. “Harass” is defined as intentional or 

negligent actions that create the likelihood of injury to listed species to such an extent as to 

significantly disrupt normal behavior patterns which include, but are not limited to, breeding, 

feeding, or sheltering. “Harm” is defined to include significant habitat modification or 

degradation that results in death or injury to listed species by significantly impairing behavioral 

patterns, including breeding, feeding, or sheltering. 

The majority of activities that may lead to the take of listed salmon in Puget Sound will 

have effects that are incidental in nature. Incidental takes are defined as takes that are incidental 

to, and not the purpose of, carrying out an otherwise lawful activity. NMFS evaluation and 

authorization for incidental takes of listed salmon may be provided through several avenues 

under the ESA. Section 7 of the ESA provides for the authorization of incidental takes 

associated with federal or federally funded actions through the completion of a consultation with 

NMFS to evaluate the effects of a proposed action. Successful completion of the consultation 

would lead to a determination by NMFS that the federal action does not jeopardize the continued 

existence of a listed population, or destroy or adversely modify its critical habitat. Non-federal 

entities may apply for permits from NMFS to incidentally take ESA-listed species under Section 

10(a)(1)(B) of the ESA. A Section 10(a)(1)(B) permit shall be issued to a non-federal entity if 

NMFS finds: 

1. The taking will be incidental. 
2

2. The applicant will, to the maximum extent practicable, minimize and mitigate the 

impacts of such taking. 

3. The applicant will ensure that adequate funding for a species “Conservation Plan,” 

required for submittal with the take application, will be provided. 

4. The taking will not appreciably reduce the likelihood of the survival and recovery of 

the species in the wild. 

5. Any other measures that the Secretary of Commerce may require as being necessary 

or appropriate will be met. 

Completed Section 7 consultations and Section 10 permits generally include measures, terms, 

and conditions required to limit or further minimize the incidental takes that may occur through 

the proposed action requiring authorization. 

An additional means by which takes of recently listed threatened species, including Puget 

Sound chinook salmon and Hood Canal summer-run chum salmon, may be evaluated and 

authorized by NMFS is through the ESA Section 4(d) Rule issued for these species (50 Code of 

Federal Regulations 223.203 – 65 Federal Register 42422, July 10, 2000). Under the Rule, ESA 

Section 9 take prohibitions do not apply to actions that are in compliance with criteria specified 

in the Rule that insure consistency with ESA requirements, and that avoid or minimize the risk of 

take of listed threatened salmon. NMFS has identified 13 programs or subsets of activities in the 

Rule that are conducted in a way that contribute to conserving the listed ESUs, and where NMFS 

determines that added protection through federal regulation is not necessary or advisable for 

conservation of the ESU. Included in the 13 programs or “limits” is a category that limits 

application of take prohibitions to activity associated with salmonid artificial propagation 

programs, provided that such activity complies with certain criteria specified under the 4(d) Rule 

limit (50 CFR 223.203(b)(5)(i)). 

Among the activities in the Puget Sound region that are now subject to federal 

prohibitions on the take of listed salmon and the need for NMFS evaluation and authorization of 

listed fish effects is the private Atlantic salmon (Salmo salar) aquaculture industry. The purpose 

of this review is to gather the best scientific and commercial information available to evaluate 

and determine the likely effects of Atlantic salmon aquaculture in the region on the survival and 

recovery of the listed chinook and summer-run chum salmon populations. It will also serve to 

indicate appropriate measures recommended by the NMFS Northwest Fisheries Science Center 

for minimizing risks of Atlantic salmon aquaculture to the listed salmon populations. This 

document will therefore provide the scientific basis for federal regulatory agency direction for 

the appropriate management of the industry in Puget Sound for listed salmon protection 

purposes. However, it is mainly intended to serve as the key resource for subsequent NMFS 

evaluation under the ESA of the specific, private Atlantic salmon aquaculture operations in the 

Puget Sound region for effects on listed fish. These site-specific NMFS evaluations will 

determine whether individual operations may be authorized for takes through the ESA Section 7 

or Section 10 permit processes, or for limits on listed fish take prohibitions under the new ESA 

Section 4(d) Rule for the listed chinook and summer-run chum salmon populations. 
3

Concerns Regarding Salmon Farming in Puget Sound 

The artificial propagation of salmon and trout in the Pacific Northwest has come under 

increasing scrutiny in recent years. This is due to the recognition that hatchery-cultured salmon 

and trout have the potential to adversely impact natural populations (Busack and Currens 1995, 

ODFW 2000). Although the greater weight of attention has been focused on the large complex 

of federal, state, tribal, and cooperative Pacific salmon hatcheries in western states, concerns 

about the potential adverse impacts of private trout and Atlantic salmon culture in Washington 

have been expressed by some scientists and fisheries managers, as well as by some advocacy 

groups and the popular media (print and internet). 

Uncertainty about genetic and ecological interactions and the transmission of disease 

among Atlantic and Pacific salmon are most commonly voiced. In testimony before the 

Washington State Pollution Control Hearings Board (PCHB 1997a), it was stated that Atlantic 

salmon had the potential for hybridization with Pacific salmon, based on a recent unpublished 

Canadian laboratory study, and that it was not impossible that the 369,000 Atlantic salmon which 

escaped into Puget Sound in 1997 would produce 10 million healthy smolts in local rivers 

(PCHB 1997b). The Marine Environmental Consortium, a coalition of Northwest environmental 

advocacy groups, considers escaped Atlantic salmon a serious threat to endangered species in 

Puget Sound, according to its spokesperson, Barbara Stenson (Le 1999). Assertions such as 

University of Victoria student John Volpe’s that “native stocks will have to move aside to make 

room for a new exotic” have appeared in the popular press (Marsh 1999). Dale Kelly, executive 

director of the Alaska Troller’s Association, declared that the impacts of escaped Atlantic salmon 

on Pacific salmon were frightening (Dobbyn 2001). Tom Geiger, outreach director of the 

Washington Environmental Council, said Atlantic salmon compete for food and shelter with 

native fish that are already struggling for survival (Morente 2001). The Alaska Department of 

Fish and Game has expressed concern that escaped Atlantic salmon from salmon farms in 

Washington State and British Columbia, Canada, will compete with wild salmon and spread 

diseases and parasites for which Pacific salmon have little resistance (ADF&G 1999). A letter a 

constituent sent to U.S. Senator Ted Stevens of Alaska read in part, “The continued introduction 

of Atlantic salmon to the marine habitat of British Columbia and Washington State will 

inevitably have negative biological impacts. These will include displacement, hybridization, and 

the introduction of alien...disease” (Gilbertsen 1997). 

Scope of Literature Review 

This paper reviews the potential risks from escapes of Atlantic salmon into the Puget 

Sound chinook salmon ESU and the Hood Canal summer-run chum salmon ESU, both of which 

are listed as threatened under the ESA. These hypothetical risks include the potential for escaped 

Atlantic salmon to interbreed with, displace, compete with, or prey upon listed Puget Sound 

chinook salmon or Hood Canal summer-run chum salmon. It is imperative to understand that 

this review pertains to potential impacts in just these two ESUs and is not intended to be an 

evaluation of potential biological risks associated with Atlantic salmon farming anywhere in the 

world except Puget Sound, Washington. Since regulatory and management policies, ecological 

factors, and biological and geophysical parameters are not uniform worldwide, potential adverse 
4

biological impacts of artificially propagated Atlantic salmon on Pacific salmon in Puget Sound 

may not be the same as Atlantic salmon impacts observed in other parts of the world, especially 

in locations where Atlantic salmon are native. Social issues related to salmon farming in Puget 

Sound, such as the decline in consumer price of wild Pacific salmon due to free market 

competition from farmed salmon, are not addressed, as they do not pertain to potential risks for 

ESA-listed salmonids. 

Specific sections of this paper review the literature concerning risks of hybridization 

between Atlantic and Pacific salmon, the colonization of aquatic environments by Atlantic 

salmon, and interactions of wild salmon and genetically altered transgenic salmon. A section 

concerning occurrence and transmission of waterborne salmon disease reviews the risk that 

cultured Atlantic salmon will introduce diseases into Puget Sound ecosystems. Information 

regarding genetic consequences and disease incidences associated with artificially propagated 

Pacific salmon are presented to provide a perspective against which to evaluate the potential 

adverse impacts of farmed Atlantic salmon for these same elements. The potential for adverse 

ecological impacts of escaped Atlantic salmon in the Pacific Northwest, specifically, competition 

for food and space, and predation, are then reviewed. That is followed by a summary, for 

comparative purposes, of known adverse ecological impacts associated with artificial 

propagation of Pacific salmon in the Pacific Northwest. 

For additional perspective, a review of impacts of other nonindigenous fish species in the 

Pacific Northwest is given, followed by a comparison of the number of artificially propagated 

Atlantic and Pacific salmon found in natural environments (by escape or release) on the West 

Coast of North America. Reviews of previous evaluations of the potential adverse impacts of 

escaped Atlantic salmon in Puget Sound are then presented. These include the findings of the 

PCHB and a perspective on escaped Atlantic salmon from the Washington Department of Fish 

and Wildlife (WDFW). In addition, a brief review of the potential impact of salmon farms on 

Essential Fish Habitat (EFH) is provided. The volume of solid waste discharged from salmon 

farms onto EFH and the amount of solid waste discharged from fish processing plants onto EFH 

are presented to provide a comparison of the amount of nearshore wastes produced by two 

different methods of fish production. The scale of marina development in Puget Sound is 

examined for comparison to an activity which uses similar nearshore habitat and also has the 

potential for environmental impacts on salmon EFH. Pertinent excerpts from the Artificial 

Propagation of Fish and Shellfish section of the EFH Provision of the Magnuson-Steven 

Fisheries Conservation and Management Act are presented. Finally, a list of managing agencies 

and specific regulations pertaining to private and public aquaculture in Puget Sound is presented 

to show current government oversight of salmon farming. 

Previous Investigations of Salmon Farming in the Pacific Northwest 

Much of the material presented here has been taken from previous NMFS evaluations of 

the risks of Atlantic salmon in Pacific coast states or from NMFS’ ESA-related status reviews of 

West Coast salmonids. These evaluations include: The Net-Pen Salmon Farming Industry in the 

Pacific Northwest, by the Resource Enhancement and Utilization Technologies Division of the 

Northwest Fisheries Science Center (Nash 2001), and oral and written testimony (oral by Conrad 
5

Mahnken, written by William Waknitz, both of the Northwest Fisheries Science Center’s 

Manchester Research Station) before the Washington State Senate on September 16, 1999. In 

addition, material from recent salmon farming reviews by the PCHB and WDFW is included in 

the present review. 
6
7

ORIGIN OF ATLANTIC SALMON STOCKS IN PUGET 

SOUND 

Beginning in 1971, scientists from the NMFS Northwest Fisheries Science Center tested 

the feasibility of rearing New England stocks of Atlantic salmon in seawater net-pens in Puget 

Sound to provide 3.5 million eyed eggs annually for restoring depleted runs in southern New 

England as part of a cooperative effort between the U. S. Fish and Wildlife Service (USFWS) 

and NMFS (Mighell 1981, Harrell et al. 1984). Between 1971 and 1983, NMFS received eggs 

from many North American stocks, including the Grand Cascapedia River in Quebec (via 

Oregon State), and the Penobscot, Union, St. John, and Connecticut rivers in the United States. 

Prior to the transfer of eggs from New England to Washington, all Atlantic salmon eggs 

sent to the NMFS Manchester Research Station were examined according to the Code of Federal 

Regulations (50 CFR) and certified by federal pathologists to be free of bacterial and viral 

pathogens. However, few eggs were ever sent back to New England due to the reluctance of 

East Coast fisheries managers to accept eggs from Atlantic salmon which had been grown in 

waters inhabited by Pacific salmon and thereby exposed to indigenous Puget Sound salmon 

diseases. A panel of New England state and federal fisheries officials meeting at Newton 

Corner, Massachusetts, in March 1984 determined that the risk of introducing Pacific salmon 

diseases to New England Atlantic salmon populations due to raising Atlantic salmon in the 

proximity of Pacific salmon in Puget Sound was great and had rendered the eggs unfit for 

transfer back to the East Coast. 

As a result of this decision, millions of Atlantic salmon eggs originally meant for New 

England restoration programs were available for distribution to salmon farmers in Washington. 

These eggs proved to be a boon to the local industry as, by this time, it was clear that Atlantic 

salmon grown in Puget Sound salmon farms were superior to the coho salmon (O. kisutch) 

originally used by local salmon farmers in all aspects of culture, including survival to hatch, 

growth rate in freshwater and seawater enclosures, size at harvest, and contrary to East Coast 

opinion, resistance to infectious diseases (Mighell 1981, Waknitz 1981, Amos and Appleby 

1999). 

In Washington now about 67.5 total hectares (ha) are leased by companies for 

commercial salmon net-pens, although not all the leased area is being used (WDNR 2001). The 

leased area extends to the perimeter of the anchoring system, so the actual area covered by 

floating structures is much less. The 10 commercial sites currently operational in Puget Sound 

have a total of 53 ha under lease from the State (ranging in size from 0.8 to 9.7 ha per site), with 

a total of 8.7 ha permitted for internal pen structures for all Puget Sound salmon farms combined 

(range 1,951 m2

 to 15,793m2) (K. Bright1). 

 

1

 K. Bright, Washington Fish Growers Association, 10420 173rd Ave. SW, Rochester, WA 98579. Pers. commun., 

February 12, 2001. 
8
9

POTENTIAL GENETIC IMPACTS OF ATLANTIC SALMON 

CULTURE IN THE PUGET SOUND CHINOOK AND HOOD 

CANAL SUMMER-RUN CHUM SALMON ESUS

Potential Genetic Interactions of Artificially Propagated Pacific and 

Atlantic Salmon 

A major concern with artificial propagation of salmonids in hatcheries, which includes 

the farming of Pacific salmonids and Atlantic salmon, is the potential genetic effects of released 

fish (hatcheries) and inadvertent escapees (farming) on native salmonids. For the salmon 

farming industry in British Columbia, where both Pacific and Atlantic salmon are extensively 

farmed, a recent study listed three major areas of concern (EAO 1997): 

• Hybridization between Atlantic and Pacific salmon 

• Genetic dilution and alteration of the wild salmonid gene pool 

• Interactions between wild salmon and genetically altered transgenic salmon 

These concerns are both geographically and species specific. For private aquaculture in Puget 

Sound net-pens, the concerns expressed by citizen groups and agencies have been primarily 

associated with farmed Atlantic salmon, as Pacific salmon, with rare exception, are not cultured 

by private enterprises. 

Hybridization between Atlantic and Pacific Salmon 

Potential Genetic Compatibility 

No genetic compatibility between Atlantic salmon (genus Salmo) and wild Pacific 

salmon (genus Oncorhynchus) has been reported in the Pacific Northwest or elsewhere. 

Similarly, under controlled and protected laboratory conditions, where survival of hybrid 

offspring should be optimized, genetically viable hybrids between Atlantic and Pacific salmonid 

species have been impossible to produce. Refstie and Gjedrem (1975), Sutterlin et al. (1977), 

and Blanc and Chevassus (1979, 1982) found that crosses between Atlantic salmon and rainbow 

trout (O. mykiss) failed to produce any viable progeny. A similar lack of survival was observed 

in attempted hybridization of Atlantic salmon and coho salmon (Chevassus 1979) and Atlantic 

salmon and pink salmon (O. gorbuscha) (Loginova and Krasnoperova 1982). Gray et al. (1993) 

attempted to produce diploid and triploid hybrids by crossing Atlantic salmon with chum and 

coho salmon and rainbow trout. All embryos died in early developmental stages, leading to the 

conclusion that hybridization of Atlantic salmon with Pacific salmon species was unlikely to 

happen. 

Recently, two pilot studies from British Columbia have provided more data regarding the 

lack of genetic compatibility between Atlantic and Pacific salmon (R. Devlin, Department of 

Fisheries and Oceans Canada, reported in Alverson and Ruggerone 1997). In the first study 

using a small number of eggs, crosses with Atlantic salmon produced a few hybrids with pink 
10

salmon, but no hybrids with coho, chum, chinook, sockeye salmon (O. nerka), and rainbow trout 

(Table 1). In the same experiment, by contrast, the interspecific crosses between Oncorhynchus

species produced hybrids with survivals to hatch ranging from 10 to 90% in 15 of the 42 crosses, 

with each species of Pacific salmon readily producing hybrids with between 2 and 5 other Pacific 

salmon species, confirming previous observations of this genus (Foerster 1935, Seeb et al. 1988). 

It should be noted that because of dissimilar spawning times between Atlantic salmon (fall 

spawning) and steelhead (spring spawning) (O. mykiss), this particular cross was performed 

using cryopreserved Atlantic salmon sperm. 

In the second study using a larger number of eggs, and involving crosses between 

Atlantic salmon and rainbow and steelhead trout, coho, chum, chinook, and pink salmon, a few 

hybrids were also produced (Table 2). It should be noted that because of dissimilar spawning 

times between Atlantic salmon (fall spawning) and cutthroat trout (winter spawning) (O. clarki), 

this particular cross was performed using cryopreserved Atlantic salmon sperm. Approximately 

6.1% of the steelhead x Atlantic salmon, and 0.02% of the pink salmon x Atlantic salmon 

hybrids survived to the hatching stage. Surviving progeny exhibited deformities such as 

curvature of the spine and none of the survivors showed any signs of maturity after four years 

(Noakes et al. 2000). The results pertaining to survival to the hatching stage were presented as 

evidence of hybridization potential between Atlantic salmon and Pacific salmon in hearings 

before the PCHB (PCHB 96-257-266, and 97-110, 1998). However, the PCHB found that 

evidence of hybridization was not supported by this study, and there was no reasonable potential 

for hybridization between escaped Atlantic salmon and native Pacific salmon in Puget Sound 

based on current knowledge and behavior (PCHB 1998). No concerns about these studies’ 

evidence of hybridization potential resulting from the introduction of hatchery stocks of Pacific 

salmonids into natural habitats were addressed to the PCHB or voiced in the popular press, 

despite the readily produced hybrids in Pacific salmon compared to the low percentage of 

survival to hatch observed between the Atlantic salmon x pink salmon cross (Table 1). 

The few Atlantic x steelhead hybrids produced resulted from experiments conducted in 

vitro, and actual Atlantic/steelhead hybridization would probably not happen under natural 

conditions (no cryopreservation) in Washington State. The Atlantic salmon stocks used in 

Washington begin spawning in early October and have finished spawning by the end of 

November (Waknitz unpubl. data). Wild steelhead in western Washington spawn from March 

through June (Freymond and Foley 1985). Therefore, there is virtually no opportunity for 

Atlantic salmon to spawn with native steelhead outside the laboratory. 

Atlantic salmon x Pacific salmon hybrids have not been observed in other regions of 

North or South America or New Zealand. In eastern North America, non-native rainbow trout 

have been successfully introduced into 12 states or provinces within the natural range of Atlantic 

salmon (MacCrimmon 1971). No naturally produced hybrids have been reported in the 30 to 

100 years subsequent to this occurrence, even though many adult Atlantic salmon are examined 

at weirs and traps sometime during their upstream migration (NMFS/USFWS 1999). Similarly, 

no hybrids between Atlantic salmon and brown trout (Salmo trutta), rainbow trout or brook trout 

(Salvelinus fontinalis) have been reported in South America or New Zealand, where all four of 

these species are not native to those locations (MacCrimmon 1971, Lever 1996). 
11

Table 1. Percent survival to hatch from various Atlantic salmon x Pacific salmon crosses, or interspecific 

Pacific salmon x Pacific salmon crosses, using a small number of eggs (less than 500). (Data from EAO 

1997.) Intraspecific crosses (nonhybrids) are in bold. 

 Female: 

Male: 

Atlantic Sockeye Chum Pink Coho Chinook Rainbow 

trout 

Atlantic 64.1 0.0 0.0 0.0 0.0 0.0 0.0 

Sockeye 0.0 88.4 90.9 16.9 0.0 0.3 0.0 

Chum 0.0 61.9 94.9 85.7 0.0 0.0 0.0 

Pink 5.5 77.7 54.2 83.9 14.9 93.2 15.8 

Coho 0.0 82.9 0.0 1.5 73.3 0.0 0.7 

Chinook 0.0 43.2 35.3 64.3 52.3 94.3 10.6 

Rainbow trout 0.0 0.0 0.0 0.0 0.0 0.0 54.6 

Table 2. Percent survival to hatch from various Atlantic salmon x Pacific salmon crosses, using a large 

number of eggs (more than 2,000). (Data from EAO 1997.) Crosses not attempted are 

represented by a blank cell. 

 Female: 

Male: 

Atlantic Sockeye Chum Steelhead Pink Coho Chinook Cutthroat Rainbow

Trout 

Atlantic 0.012 0.12 6.07 0.018 0.00 0.012 0.00 0.098 

Sockeye 0.00 

Chum 0.014 

Steelhead 0.0012 

Pink 0.36 

Coho 0.014 

Chinook 0.023 

Cutthroat 0.00 

Rainbow 0.0017 
12

No natural hybrids between Atlantic salmon and Pacific salmonids have been reported in 

Europe, despite the fact that introduced rainbow/steelhead trout, brook trout, coho salmon, and 

pink salmon have all established naturalized populations to some degree within the native range 

of Atlantic salmon on the European continent (MacCrimmon and Campbell 1969, MacCrimmon 

1971, Berg 1977, Lever 1996). 

Potential Contribution from Precocious Male Atlantic Salmon 

It has been suggested that spawning escaped Atlantic salmon may produce precocious 

male Atlantic salmon which will attempt to breed with Pacific salmon. It was hypothesized that, 

while not actually capable of producing hybrids, these precocious males might produce genetic 

disturbances by interfering with wild salmonid breeding behavior, and by beating Pacific salmon 

males to the eggs in the redd, produce nonviable eggs that would reduce the number of juvenile 

salmonids available for recruitment in depressed populations (Group Participants 2001). 

Although it is possible that this could happen in some locations, the risk of this scenario 

occurring in Puget Sound tributaries is low for a number of reasons. 

First, salmon farmers in Puget Sound use Atlantic salmon derived from stocks provided 

to them by NMFS in the mid-1980s, primarily Penobscot River and Grand Cascapedia River 

strains. The Penobscot River hatchery strain is known to have a remarkably low incidence of 

early maturity, either after 1 or 2 years in freshwater (precocious male parr), or at 2 or 3 years of 

age (1 year at sea), known as grilse (Ritter et al. 1986). Since age at maturity is a genetically 

inherited trait which can then be influenced by changes in environmental conditions (Randle et 

al. 1986), the Penobscot River Atlantic salmon strain now used in Puget Sound salmon farms 

begins with an especially low potential for adverse impacts from precocious males, assuming 

that naturally spawned juvenile male Atlantic salmon ever become numerous in Puget Sound 

tributaries. 

Second, smoltification and early male maturity are mutually exclusive events (Thorpe 

1986), and precocious parr Atlantic salmon do not survive transfer to full strength seawater 

(Waknitz unpubl. data), due primarily to the fact that they have invested their metabolic 

resources in producing gametes instead of acquiring the ability to osmoregulate in seawater. 

Therefore, precocious parr are directly selected against in Puget Sound domesticated Atlantic 

salmon populations every generation at the time of transfer to seawater, where they are 

eliminated from that particular brood. 

Third, protocols common to salmon farming also directly, if inadvertently, select against 

the production of precocious male Atlantic salmon in local salmon farms. To reduce freshwater 

rearing costs, local salmon farmers cull juveniles which do not smolt at 1 year of age. This 

serves to select against early maturity because 1-year-old smolts are known to produce fewer 

precocious parr and grilse than 2-year-old smolts (Ritter et al. 1986). Furthermore, Atlantic 

salmon that mature as grilse after only 1 year in seawater are not retained for broodstock by 

growers in Puget Sound because fish that never grow to a large size are not as profitable as those 

that do. Grilse are known to produce more precocious parr than older Atlantic salmon (Ritter et 

al. 1986). 
13

Fourth, it may not be a cause for concern that low population abundance in some Pacific 

salmon stocks might create conditions favorable to hybridization by male Atlantic salmon parr, if 

any are ever produced in Puget Sound tributaries. In a study of wild Atlantic salmon and brown 

trout in Newfoundland, McGowan and Davidson (1992) found that it was unlikely that a 

disparity in species abundance was a principal cause of interspecific hybridization by Atlantic 

salmon. 

Therefore, the unusually low incidence of early maturity in the Atlantic salmon strain 

from the Penobscot River, which Ritter et al. (1986) noted as “striking” compared to the much 

higher incidences of early maturity observed in nearby Canadian populations in Quebec and New 

Brunswick, has been further reduced by generations of directed selection by Puget Sound salmon 

farmers against this particular life-history type. Similarly, no precocious parr were observed in 

several generations of the Grand Cascapedia River population held at the NMFS Manchester 

Research Station between 1971 and 1983 prior to this stock being made available to the public 

(Mighell 1981, Waknitz unpubl. data). 

Hybridization between Atlantic Salmon and Brown Trout 

While viable hybrids between Atlantic salmon and the Pacific salmonid species are 

difficult to produce in the laboratory and have not been observed in natural environments, 

hybrids between Atlantic salmon and a congeneric species, the brown trout, are relatively 

successful. Viable Atlantic salmon x brown trout hybrids in the laboratory have been reported 

by Suzuki and Fukuda (1971), Refstie and Gjedrem (1975), and Blanc and Chevassus (1982). 

Successful hybridization under natural conditions has been reported in many European 

countries where brown trout are native, and also in North America where the brown trout has 

been introduced (Verspoor and Hammar 1991). The frequency of natural Atlantic salmon x 

brown trout hybrids in Europe and North America ranges from 0.1 to 13.2% of juveniles in river 

systems (Jordan and Verspoor 1993) and appears to be increasing relative to pre-aquaculture 

levels in Europe (Hindar et al. 1998). McGowan and Davidson (1992) cite the breakdown in 

pre-reproductive isolating mechanisms in Newfoundland (abundance of mature Atlantic salmon 

parr) as the principal mechanism for such natural hybridization between wild brown trout and 

wild Atlantic salmon. Hindar et al. (1998) reported that although a disproportionate number of 

hybrids were the product of pairings involving Atlantic salmon females, there was no evidence 

that escaped farmed Atlantic salmon females produced more hybrids than wild females. 

Youngson et al. (1993), on the other hand, had previously reported that escaped females in 

western and northern Scotland rivers hybridized with brown trout more frequently. Wilkins et al. 

(1993) found that male hybrids were fertile, and when back-crossed with female Atlantic salmon, 

produced about 1% diploid progeny. Galbreath and Thorgaard (1995) reported that back-crosses 

between male diploid, male triploid, and female diploid Atlantic salmon x brown trout hybrids 

and both parental species produced either nonviable or sterile progeny. 

Brown trout have established naturalized populations in many locations in the Columbia 

River basin (Wydoski and Whitney 1979, WDFW 2002) and in about a dozen rivers and lakes on 

Vancouver Island (Idyll 1942, Lever 1996, Wightman et al. 1998, BC.com 2001). Brown trout 

in the mid-Columbia River region above Bonneville Dam and below Grand Coulee Dam are so 

large they are commonly mistaken for adult chinook salmon (Shangle 2001). However, no 
14

reports of hybridization between introduced brown trout and native Pacific salmon in these areas 

were found in this literature review, despite the fact that many of these brown trout populations 

have been naturalized in these locations for over half a century, during which time local native 

and hatchery populations of salmonids have been subject to frequent observations. No scientific 

or media reports expressing apprehension about brown trout x Pacific salmon hybrids were 

found in the process of this review, suggesting that hybrids resulting from escaped Atlantic 

salmon are viewed as a threat to wild Pacific salmon in the Pacific Northwest, while the same 

hypothetical threats that could also be associated with brown trout have either been accepted or 

not recognized. 

The propensity of Atlantic salmon to produce successful hybrids with brown trout and 

not with Pacific salmonids may be related to the phylogenetic distance between the two groups. 

Neave (1958) postulated that the putative ancestors of the Salmo group migrated to the Pacific 

600,000 to 1,000,000 years ago, were subsequently isolated by land bridges, and evolved to the 

ancestral Oncorhynchid form. The ancestral form subsequently developed to form the separate 

Oncorhynchus species (Simon 1963). McKay et al. (1996), based on DNA sequence analysis of 

growth hormone type-2 and mitochondrial NADH dehydrogenase subunit 3 gene, estimated that, 

at a minimum, the major divergence between the genus Salmo and the genus Oncorhynchus

occurred 18 million years ago, while speciation within the genus Oncorhynchus began about 10 

million years ago. 

Hybridization among Pacific Salmon 

Attesting to their phylogenetic similarity, interspecific hybrids within the Oncorhynchids 

are relatively successful, as noted above. Foerster (1935) was among the first to report 

successful hybrids between controlled matings of sockeye, chum, pink and chinook salmon. 

Two-year-old chum salmon x pink salmon hybrids released from a hatchery in Puget Sound 

returned at a higher rate than pure pink salmon (Simon and Noble 1968). However, as Simon 

and Noble (1968) observed: “The fact that hybrids can be produced artificially is of little 

consequence to natural circumstances unless: (a) fertility of the hybrids is evident, and; (b) the 

same crosses occur in nature.” These requirements were met in crosses of chum and pink 

salmon in British Columbia, where natural hybrids have been observed (Hunter 1949). On the 

whole, however, reports of natural hybrids among anadromous salmonids have been limited. 

Bartley et al. (1990) reported on natural hybridization between chinook and coho salmon in a 

northern California river, and Rosenfield (1998) reported a natural pink x chinook salmon hybrid 

from the St. Mary’s River in Michigan. The situation for non-anadromous salmonids is very 

different. Hybridization between introduced rainbow trout and native cutthroat trout appears to 

be almost ubiquitous throughout the interior part of western North America, and has been 

enormously detrimental to the latter species (Gresswell 1988, Behnke 1992). 

Genetic Dilution and Alteration of the Wild Salmon Gene Pool 

Adverse genetic and ecological effects on wild Atlantic salmon populations due to 

releases or escapes of artificially propagated Atlantic salmon from public hatcheries and private 

net-pens have been reported in Norway, Scotland, Ireland, and the Canadian Maritime Provinces. 
15

For wild, native Atlantic salmon, these include a reduction in their genetic diversity and capacity 

to evolve, a result of dilution of genetic diversity by interbreeding with artificially propagated 

fish, and direct competition for food and space (Einum and Fleming 1997, Gross 1998). 

Such adverse effects happened in Europe and eastern North America because both the 

cultured and wild fish were Atlantic salmon. However, Atlantic salmon escaping into the Puget 

Sound and Hood Canal ESUs for chinook and summer-run chum salmon will not have 

conspecific or congeneric wild individuals with which to interact. In the Pacific Northwest 

region, releases of artificially propagated Pacific salmon, not the escape of Atlantic salmon, have 

been shown to produce impacts on native Pacific salmon that are analogous to those found 

between artificially propagated and wild Atlantic salmon in Europe and eastern North America. 

Adverse genetic and ecological interactions on local wild Pacific salmon populations 

from artificially propagated Pacific salmon have been well-documented by Weitkamp et al. 

(1995), Busby et al. (1996), Hard et al. (1996), EAO (1997), Gustafson et al. (1997), Johnson et 

al. (1997, 1999), and Myers et al. (1998a) in reviews of this large body of literature. Over the 

last 100 years, no detrimental genetic effects related to escaped or planted Atlantic salmon have 

been reported in Puget Sound or western North America. 

Potential Impact of Transgenic Atlantic Salmon 

As with other agricultural sectors, there is considerable interest within the fish farming 

and fish enhancement sectors to improve growth or survival of fish or shellfish through genomic 

or chromosomal manipulations. For example, triploid (treated to produce 3 instead of 2 

chromosome copies) California-strain rainbow trout were planted in about 75 lakes in 

Washington this year to provide anglers with opportunities for large fish (WDFW 2002). The 

use of triploids in fish farming is considered to be a low risk endeavor in Washington, and has 

been suggested as one of the means to avoid genetic interactions, remote as they are, between 

Atlantic salmon and native salmonids (PCHB 1998). However, in recent years the role of 

transgenics (descendants of genetically engineered parents whereby introduced DNA has been 

incorporated and inherited) in traditional farming has been a controversial topic. The potential 

risk is thought to be that transgenic fish, should they escape from fish farms, may reproduce 

successfully with wild or other transgenic fish and produce offspring that may eventually adapt 

to their local environments. This is a topic that will receive considerable debate in the years to 

come. There is no evidence in the literature that transgenic fish have been raised or are currently 

being raised in Puget Sound waters, and at present there are no plans to raise them in the future 

(P. Granger2

). The formally adopted position of the Washington Fish Growers Association is as 

follows: “Transgenic fish (as defined by actual transfer of genes from one species to another 

species) are not used in commercial production in Washington State today and should not be 

used here or elsewhere in the future unless they are proven healthy and nutritious, safe for human 

 

2

 P. Granger, Washington Fish Growers Association, 10420 173rd Ave. SW, Rochester, WA 98579. Pers. commun., 

February 12, 2001. 
16

consumption and of minimal risk to the environment. This would mean approval by appropriate 

state and federal agencies” (D. Swecker3

). 

 

3

 D. Swecker, Washington Fish Growers Association, 10420 173rd Ave. SW, Rochester, WA 98579. Pers. 

commun., March 4, 2002. 
17

POTENTIAL FOR COLONIZATION OF PUGET SOUND 

CHINOOK AND HOOD CANAL SUMMER-RUN CHUM 

SALMON ESUS BY ATLANTIC SALMON 

Success of Atlantic Salmon Introductions Worldwide 

Worldwide, there have been several hundred attempts to establish Atlantic salmon 

outside their native range, and with two exceptions in barren habitat, these have inevitably failed 

(MacCrimmon and Gots 1979, Lever 1996). On the other hand, there are many reports regarding 

other non-native species that eventually became established after first experiencing numerous 

failures, especially introductions involving plants and invertebrates (Williamson 1996). 

However, most Atlantic salmon introductions have been well-matched to habitat (northern and 

mountainous states or southern provinces) with optimal environmental conditions for the salmon, 

have included large numbers over many years, and still have failed. Thus, it is the total number 

of failed introductions over the last century that is the basis of the risk assessment presented 

below. 

Success of Atlantic Salmon Introductions in the United States 

In the past century, there have been numerous attempts in the United States and 

elsewhere to establish Atlantic salmon outside their native range. At least 170 attempts occurred 

in 34 different states where Atlantic salmon were not native, including Washington, Oregon, and 

California (MacCrimmon and Gots 1979). None of these efforts was successful. No 

reproduction by Atlantic salmon was verified after introductions in the waters of these states 

(MacCrimmon and Gots 1979, Alverson and Ruggerone 1997, Dill and Cordone 1997). 

Success of Atlantic Salmon Introductions in the Pacific Northwest 

The initial transfer of Atlantic salmon to Washington occurred in 1904 (MacCrimmon 

and Gots 1979). Attempts to introduce this species, as well as plantings for recreational 

purposes, continued until about 1991 (Coleman and Rasch 1981, Amos and Appleby 1999). 

Occasional releases of Atlantic salmon into high mountain lakes in Washington have since been 

made. Sea-run and landlocked strains (originally from NMFS) were used, but neither life-history 

form succeeded in establishing self-perpetuating populations. 

Several Atlantic salmon farmers in Washington rear juveniles in the Chehalis River basin 

prior to transfer to seawater in Puget Sound. Since the mid-1980s, escaped Atlantic salmon 

smolts have been captured in traps designed to monitor the out-migration of juvenile Pacific 

salmon (Seiler et al. 1995). However, as of 1998, no returning adult Atlantic salmon have been 

encountered at adult salmon traps on several tributaries of the Chehalis River system, or been 

caught in tribal gill-net fisheries, which capture about 10% of all upstream migrating adults in 
18

the main stem of the Chehalis River (D. Seiler4). If 20 adult Atlantic salmon were returning to 

the Chehalis River in a given year, a 10% level of sampling would give an 88% percent chance 

of observing at least one Atlantic salmon if it returned at the same time as the tribal fisheries in 

the summer through early fall (R. Kope5

). Therefore, the probability of not capturing an adult 

Atlantic salmon if they were numerous enough to have a hypothetical negative impact in the 

Chehalis River is small. 

Between 1905 and 1934, the government of British Columbia released 7.5 million 

juvenile Atlantic salmon into local waters, primarily on the east coast of Vancouver Island and 

the lower Fraser River (MacCrimmon and Gots 1979, Alverson and Ruggerone 1997). These 

releases were not successful in establishing Atlantic salmon populations in the province (Carl et 

al. 1959, Hart 1973), although some natural reproduction may have occurred in the Cowichan 

River, as specimens thought to have resulted from the planting of Atlantic salmon were taken 

until May 1926 (Dymond 1932). The Department of Fisheries and Oceans Canada (DFO 

Canada) currently is carrying out a long term monitoring study, known as the Atlantic Salmon 

Watch, examining catches and sightings of Atlantic salmon to determine if self-sustaining 

populations are becoming established (Thomson and Candy 1998). Recently Volpe et al. (2000) 

reported that feral Atlantic salmon had successfully produced offspring in British Columbia. 

Locations in British Columbia where juvenile Atlantic salmon of both naturally produced (feral) 

and hatchery (escapees) origin have been captured are presented in Table 3. 

In addition to the total failure of fisheries managers to establish populations of 

anadromous Atlantic salmon outside their native range, it appears that it is extremely difficult to 

reintroduce Atlantic salmon to their native rivers in North America. In the last 100 years, 

Atlantic salmon populations in New England have declined precipitously, despite widespread 

introductions of locally derived hatchery fish, primarily from the Penobscot River (Moring et al. 

1995), a stock now used in net-pen farms in Puget Sound. Due to continued declines in 

abundance, Atlantic salmon in Maine have recently been listed as an endangered species under 

the ESA (USDOI and USDOC 2000). Emery (1985) and Crawford (2001) noted that in historic 

Atlantic salmon habitat in Lake Ontario, attempts to reestablish Atlantic salmon populations 

have not been successful. However, introduced Pacific salmonids have succeeded in establishing 

self-reproducing populations throughout the Great Lakes (Brown 1975), although it appears that 

many populations of introduced salmon and trout in the Great Lakes would face an immediate 

risk of local extinction without continued supplemental stocking (Crawford 2001). USFWS 

(1982) reported that Pacific salmon and trout, as well as brown trout from Europe, were 

prevalent in Canadian and United States tributaries of Lake Ontario, a system where Atlantic 

salmon were once a common species. Coho salmon were observed spawning in 48 different 

streams, kokanee (sockeye salmon life-history form) in 4 streams, chinook salmon in 52 streams, 

rainbow trout/steelhead in 62 streams, and brown trout in 25 streams. Atlantic salmon were not 

observed in any tributary of Lake Ontario in this 1982 study, having been extirpated from the 

Lake Ontario system by 1904. 

Lever (1996) reported that, worldwide, no self-sustaining populations of anadromous 

Atlantic salmon have been established outside the natural range of this species, although 

 

4

 D. Seiler, WDFW, 600 Capitol Way N, Olympia, WA 98501. Pers. commun., September 1, 1999. 

5

 R. Kope, NMFS, 2725 Montlake Blvd. E, Seattle, WA 98112. Pers. commun., October 16, 2001. 
19

Table 3. Number of juvenile Atlantic salmon observed in British Columbia freshwater areas, 1996-2001. 

Suspected naturally produced juveniles in bold. (Data from A. Thomson, DFO Canada, Pacific 

Biological Station, Nanaimo, BC V9R 5K6. Pers. commun., April 16, 2001.) It is possible that 

the three fish observed in the Adam R. in 1999 could have been brown trout (D. Noakes, DFO 

Canada, Pacific Biological Station, Nanaimo, BC V9R 5K6. Pers. commun., February 2, 2002). 

River or lake 1996 1997 1998 1999 2000 2001 

Adam R. 3 

Amor de Cosmos R. 113 8 

Carnation Creek 1 3 1 

Georgie Lake 41 21 86 30 

Keogh R. 1 2 

Lois Lake 13 

Pye R. 1 

Stamp R. 3 

Tsitika R. 24 2 3 
20

landlocked populations appear to have become established in the Southern Hemisphere in 

Argentina and in the mountains of New Zealand. Reproduction by Atlantic salmon was 

observed subsequent to introductions in Chile and Australia, but these transfers failed to create 

self-sustaining populations. 

Possible Reasons for the Failure of Atlantic Salmon Introductions 

Primitive Hatchery Methods 

The failure of early introductions of Atlantic salmon to produce self-sustaining 

populations could have been due to the rather primitive hatchery methods used in the early 1900s 

(Volpe 2001). However, the same primitive methods that failed to establish Atlantic salmon 

anywhere in North America proved to be remarkably successful in establishing European brown 

trout, brook trout, and rainbow trout almost everywhere in the earliest days of fish culture, often 

on the first attempt (Lever 1996, Dill and Cordone 1997). With these particular salmonids, the 

success or failure of introduction appears to be associated with attributes inherent to each 

species, not with the hatchery methods employed. 

Pristine Habitats and Healthy Pacific Salmon Populations 

It has also been suggested (by University of Victoria student John Volpe) that the earlier 

attempts to establish Atlantic salmon in the Pacific Northwest failed because salmonid habitats 

had not yet been damaged and local salmonid populations were abundant, thereby preventing 

Atlantic salmon from finding an available niche to colonize (Glavin 2001). However, brown 

trout, brook trout, California-strain rainbow trout, lake trout (Salvelinus namaychus), and several 

dozen non-salmonid species all successfully colonized habitats throughout Washington and the 

rest of North America during this early period (Wydoski and Whitney 1979), indicating that the 

limited availability of suitable niches and the presence of abundant salmon populations were not 

exclusionary factors for colonization by non-native fish, including Atlantic salmon, early in the 

20th century. Moreover, attempts to establish Atlantic salmon populations in the Pacific 

Northwest were conducted under a variety of climatic conditions, variations of which have been 

show to dramatically influence the ocean survival of Pacific salmon (Beamish and Bouillon 

1993, Beamish et al. 1997, Noakes et al. 2000). Climatic conditions during the early part of the 

20th century were favorable for salmon survival as evidenced by high abundance of salmon in 

the Pacific Ocean during this period (Beamish et al. 1997, Noakes et al. 2000). Most of the 

introductions of Atlantic salmon into the Pacific Northwest occurred concurrent with this episode 

of favorable ocean conditions, but colonization failed to take place. 

Incompatible Biological Characteristics of Introduced Atlantic Salmon 

The failure of Atlantic salmon to colonize new habitat has also been attributed to other 

factors, including the inability to navigate in new environments, and to introductions that were 

made in small batches of less than several hundred thousands of individuals (Lever 1996, Dill 

and Cordone 1997). Atlantic salmon may also have “prohibitively stringent reproductive 
21

requirements, including very particular stream substrate qualities” (Crawford 2001). The 

experience in Washington and elsewhere in the world suggests that the failure of Atlantic salmon 

to establish populations after introductions is linked to incompatible biological characteristics of 

Atlantic salmon and not with the availability of suitable habitat or absence of potential 

competitors or predators. In California, attempts to establish Atlantic salmon populations have 

been discontinued because the expectation of successful introductions is “so remote that it does 

not warrant the effort or expense of an attempt” (Dill and Cordone 1997). In a review of the 

ecological and genetic effects of salmonid introductions in North America, Krueger and May 

(1991) observed that, with the notable exception of pink salmon inadvertently introduced into the 

Great Lakes, successful introductions from the accidental release or escape of salmonids has 

rarely occurred, unlike the frequent success observed with some intentionally introduced 

salmonid species such as chinook and coho salmon, and rainbow, brook, and brown trout. 

As noted above, the success of introduced salmonids in the Great Lakes may be due for 

the most part to the relatively large numbers of artificially propagated salmonids introduced into 

the Great Lakes each year. For example, between 1966 and 1998, 4 million Atlantic salmon, 336 

million chinook salmon, 81 million brown trout, 148 million coho salmon, and 174 million 

rainbow trout have been planted in all the Great Lakes combined (Crawford 2001). Atlantic 

salmon may have failed to succeed in the Great Lakes because of the low numbers of artificially 

propagated Atlantic salmon introduced compared to the much larger number of artificially 

propagated Pacific salmon and trout juveniles present in the Great Lakes (M. Gross6

). In 

addition, competitive interactions with coho and chinook salmon and rainbow and brown trout 

may limit the successful restoration of Atlantic salmon to Lake Ontario (Crawford 2001). 

Atlantic salmon are virtually the only non-native salmonid not successfully introduced to 

Washington, with the exception of Arctic char (Salvelinus alpinus) and Masu salmon 

(Oncorhynchus masou) (Wydoski and Whitney 1979). Even so, Barbara Stenson, spokesperson 

of the Marine Environmental Consortium, views escaped Atlantic salmon colonizing habitats 

throughout the Puget Sound Basin at great detriment to Pacific salmon as an inevitable outcome 

of salmon farming (Le 1999). 

The risk of anadromous Atlantic salmon establishing self-perpetuating populations 

anywhere outside their home range has been shown to be extremely remote, given that 

substantial and repeated efforts over the last 100 years have not produced a successful selfreproducing anadromous population anywhere in the world. In Oregon, the hatchery-supported 

fishery for Atlantic salmon in Hosmer Lake represents the only successful fishery produced in 

approximately eight lakes stocked with this species (Dill and Cordone 1997). In the Pacific 

Northwest, there have been no reports of self-sustaining populations resulting from deliberate or 

accidental Atlantic salmon introductions, compared to the plethora of other non-native species 

which have readily established themselves in the region. 

 

6

 M. Gross, University of Toronto, 25 Harbord St., Suite 503, Toronto, ON M5S 3G5. Pers. commun., February 24, 

2002. 
22
23

POTENTIAL FOR DISEASE TRANSMISSION OR ADVERSE 

DISEASE IMPACTS BETWEEN ATLANTIC SALMON AND 

PACIFIC SALMON IN WASHINGTON 

The occurrence and treatment of diseases is an unavoidable consequence of animal 

husbandry. This is no less true for aquatic husbandry, public and private, than for terrestrial 

farming. This section will discuss salmon diseases commonly observed in the Pacific Northwest 

and whether net-pen rearing of Atlantic salmon has a potential for adverse disease impacts 

comparable to disease risks associated with the artificial propagation of Pacific salmon in public 

hatcheries, which in turn appears to have a low risk for federally protected Pacific salmon in 

Puget Sound and Hood Canal. 

Diseases of Salmon and Trout in Hatcheries 

Freshwater salmonid diseases observed in Pacific salmon hatcheries in the Pacific 

Northwest include furunculosis, bacterial gill disease, bacterial kidney disease, botulism, enteric 

redmouth disease, cold water disease, columnaris, infectious hematopoietic necrosis, infectious 

pancreatic necrosis, viral hemorrhagic septicemia, erythrocytic inclusion body syndrome, and a 

number of parasitic infections, such as gyrodactylus, nanophyetus, costia, trichodina, 

ceratomyxosis, proliferative kidney disease, whirling disease, and ichthyophonis. These diseases 

are described in manuals by Wood (1979), Leitritz and Lewis (1980), Foott and Walker (1992), 

and Kent and Poppe (1998). 

The frequency of occurrence of these pathogens in hatcheries appears to vary 

geographically. For example, between 1988 and 1993, a greater percentage of Alaska hatcheries 

tested positive for infectious hematopoietic necrosis, viral hemorrhagic septicemia, furunculosis, 

and ceratomyxosis than hatcheries located in other western states, whereas hatcheries in Alaska 

tested positive at the lowest rate for several other salmonid pathogens (PNWFHPC 1993) (Table 

4). 

In the Pacific Northwest, hatchery diseases associated with the freshwater phase of 

salmon culture can also occur in natural seawater environments after salmon are released from 

hatcheries or transferred to net-pens for further rearing. Other pathogens, such as Vibrio 

anguillarum and various parasites, are unique to the marine environment and are normally 

encountered by wild and hatchery-reared salmonids only after they leave rivers for the sea 

(Wood 1979, Harrell et al. 1985, 1986, Kent and Poppe 1998). Salmonid diseases observed in 

salmon and trout reared in public and private net-pens in seawater in the Pacific Northwest 

include; vibriosis, furunculosis, bacterial kidney disease, enteric redmouth disease, 

myxobacterial disease, infectious hematopoietic necrosis, infectious pancreatic necrosis, viral 

hemorrhagic septicemia, erythrocytic inclusion body syndrome, rosette agent, and a number of 

parasitic infections (Kent and Poppe 1998). 
24

Table 4. Facilities (% in state or agency) testing positive for various salmonid diseases (July 1988-June 

1993). (Data from PNWFHPC 1993.) 

State or 

agency 

IHN IPN VHS EIBS BKD FUR ERM CWD PKD MC CS ICH 

AK 47.3 0.0 1.2 0.0 75.2 42.5 10.9 27.5 NSa NSa 50.0 0.0 

CA 24.2 0.0 0.0 0.0 31.2 2.2 23.0 19.4 27.9 12.0 12.8 56.3 

ID 20.2 8.7 0.0 15.5 48.4 1.8 12.3 23.6 4.3 15.6 20.4 20.7 

MT 0.0 0.0 0.0 0.0 5.6 2.5 0.8 4.2 7.7 0.0 0.0 0.0 

OR 18.1 0.3 0.0 24.6 53.1 35.9 17.8 84.8 0.0 2.9 33.3 26.2 

WA 11.5 0.7 0.1 34.2 52.6 20.1 17.0 60.3 3.5 0.0 11.9 24.4 

USFWS 37.5 1.0 0.0 27.2 84.9 23.7 20.0 34.9 0.0 0.6 30.6 24.0 

NWIFCb 2.9 0.0 0.6 NSa 51.5 14.0 18.1 39.9 56.3 0.0 0.0 15.0 

Average 20.2 1.3 0.2 14.5 50.3 17.8 15.0 36.8 12.5 4.4 18.8 20.8 a

NS = Not surveyed 

b

Northwest Indian Fisheries Commission 

Key: 

Viral Diseases 

IHN Infectious hematopoietic necrosis 

IPN Infectious pancreatic necrosis 

VHS Viral hemorrhagic septicemia 

EIBS Erythrocytic inclusion body syndrome 

Bacterial Diseases 

BKD Bacterial kidney disease 

FUR Furunculosis 

ERM Enteric redmouth disease 

CWD Coldwater disease 

Parasites 

PKD Proliferative kidney disease 

MC Whirling disease 

CS Ceratomyxa 

ICH Ichthyopthirius 
25

Salmon, like other animals, can carry pathogenic organisms without themselves being 

infected. For example, numerous bacterial species were observed in tissues of chinook salmon 

which had returned from the ocean to a hatchery in the lower Columbia River Basin, although 

the fish displayed no clinical signs of disease. Some of the bacteria observed were Listeria sp., 

Aeromonas hydrophila, Enterobacter agglomerans, Enterobacter cloacae, Staphylococcus 

aureus, Pseudomonas sp., Pasteurella sp., Vibrio parahaemolyticus, V. extorquens, V. fluvialis, 

Hafnia alvei, and Serratia liquefaciens (Sauter et al. 1987). Several of these organisms are 

known to be infectious to humans. However, the fact that such bacteria were found in hatchery 

salmon does not mean they posed a risk to humans, as the bacteria were present only at 

background levels. 

Disease Therapy 

Fish diseases and subsequent antibiotic therapy have been normal occurrences at state, 

federal, and tribal Pacific salmon hatcheries since the 1940s (WDF 1950, 1953, PNWFHPC 

1993). An examination of the disease histories of Puget Sound area Pacific salmon and trout 

hatcheries (data from 45 hatcheries) during the 1980s showed that, on average, each hatchery 

experienced disease outbreaks from about 4 different pathogenic organisms during this period, 

frequently on an annual basis (PNWFHPC 1988a-d). 

Cumulatively, salmon hatcheries in the Pacific Northwest (Alaska, Washington, Oregon, 

and Idaho), including those located in Puget Sound, experience hundreds of disease outbreaks 

every year (Wood 1979, PNWFHPC 1988a-d). It is not uncommon for a hatchery to experience 

different diseases in a relatively short period. For example, Michak and Rodgers (1989) reported 

that between 1983 and 1986 the WDFW Cowlitz Hatchery experienced Costia sp. infections on 

11 different occasions, bacterial hemorrhagic septicemia 4 times, cold water disease 9 times, 

bacterial kidney disease 8 times, and furunculosis 1 time. Disease outbreaks have been observed 

in hatchery salmon reared in saltwater in Washington since the first attempts at seawater rearing 

in the 1950s (WDF 1954, PNWFHPC 1998). 

Concerns Regarding Treatment of Diseases in Salmon Rearing Facilities 

Alexandra Morton (1997), director of Raincoast Research, Peter Knutson, commissioner 

of the Puget Sound Gillnetters Association, Arthur Whitely, board member of the Marine 

Environmental Consortium (Carrel 1998), and others (Meloy 2000) have recently expressed 

concerns that the use of chemotherapeutics in fish culture will have negative impacts on wild 

salmonids and their environment. However, the occurrence of fish diseases at public hatcheries 

or private salmon farms and their treatment with chemotherapeutics have not been shown to have 

deleterious effects on wild salmonids or their habitat. For example, it is a recommended 

procedure to bath freshly spawned eggs in an iodophor solution at state, tribal, federal, and 

private hatcheries in the Pacific Northwest (ADF&G 1983, IHOT 1995-1998, NWIFC/WDFW 

1998). However, this procedure has not been shown to be harmful to wild salmonids in the 

Pacific Northwest. In a study at several Atlantic salmon net-pen farms in Puget Sound, it was 

found that the use of antibacterial compounds in fish food had no inhibitory effect on important 
26

sediment biogeochemical processes such as bacterial densities, oxygen and ammonia fluxes, or 

interstitial ammonium and sulfate levels (Weston et al. 1994). 

Chemotherapeutants Registered for Use in the United States 

Diseases in public and private trout and salmon hatcheries in western states are normally 

treated with a variety of antibiotics and chemical baths, including oxytetracycline, Romet-30®, 

formalin, iodophores and several others (Wood 1979; PNWFHPC 1988a-d, IHOT1995-1998, 

PNWFHPC 1998). Drug therapy in federal, state, and tribal hatcheries in Washington, Oregon, 

Idaho, California, and Alaska is conducted in accordance with U.S. Food and Drug 

Administration (FDA) guidelines (Nash 2001, K. Amos7). As a result of drug therapy, 

antibiotic-resistant strains of bacterial fish pathogens have been observed in Pacific salmon 

hatcheries in the Pacific Northwest for over 40 years (WDF 1954, Wood 1979, PNWFHPC 

1993). 

Only three therapeutants (formalin, oxytetracycline, and Romet-30®) and one anesthetic 

(MS-222) are currently approved by the federal government for use with food fish in public and 

private artificial propagation facilities for salmon, trout, and catfish (Schnick 1992). However, 

the use of antibiotics in the United States is far more restrictive than in some countries. For 

example, Weston (1996) observed that 26 different antibacterial preparations were approved for 

use in Japan. This compares currently with 3 in Canada (EAO 1997) and 2 in the United States 

(Schnick 1992). 

Amount of Antibiotics Used in Fish Culture Facilities 

Given that Pacific salmon hatcheries rear thousands of metric tons (t) of fish each year, 

the amount of antibiotics used to treat bacterial salmon diseases in hatcheries is not 

inconsequential, sometimes amounting to hundreds of tons of medicated feed each year. Michak 

et al. (1990) stated that the Washington Department of Fisheries (WDF, now WDFW) hatcheries 

located in the Columbia River Basin used about 200 t of feed containing antibiotics. Since WDF 

hatcheries in the Columbia River Basin represented only about 25% of the number of all salmon 

and trout hatcheries (albeit many of the largest facilities are in the Columbia River Basin) in 

Washington State at that time (Myers et al. 1998a), it is reasonable to estimate that the total 

amount of medicated feed used by the public hatchery system in the State was about 450 t in 

1990. 

Actual or estimated annual amounts of medicated feed used in private fish culture of 

Atlantic salmon in seawater and rainbow trout in freshwater are not available at this time for the 

United States or Puget Sound. However, the amount of drugs used elsewhere in salmon farming 

has declined greatly, mostly as a result of improved husbandry practices, including development 

of effective vaccines for common fish diseases. EAO (1997) noted that salmon farmers in 

Norway used a total of 48.7 t of antibacterial drugs in 1987, and the figure had fallen to 6 t by 

1993. In 1998 it was only 0.7 t (Intrafish 2000). To put the amount of antibiotics currently used 

in Norway into perspective, it took about two level teaspoons (approximately 7 g) of antibiotic to 

 

7

 K. Amos, WDFW, 600 Capitol Way N, Olympia, WA 98501. Pers. commun., May 30, 2001. 
27

produce a metric ton of farmed salmon in Norway in 1996 (Noakes et al. 2000). Less than that is 

required today. During the same 12-year period, the production of salmon in Norway increased 

from 50,000 t to 400,000 t and the quality of product was considerably improved (ODIN 2001). 

A similar pattern of reduced drug use has occurred in British Columbia (EAO 1997). Although 

the amount of antibiotics used in Puget Sound Atlantic salmon farms has not been summarized, 

with just a few salmon farms in Puget Sound, the annual use of antibiotics in the net-pen farms 

would be relatively small compared to the amount used in other countries. 

Disease Interactions between Hatchery and Wild Salmon and Trout 

Transmissions of Disease from Hatchery to Wild Salmon 

Documented examples of disease transmission between wild and artificially propagated 

fish are not common, yet have been known to occur (Brackett 1991). For example, the planting 

of infected Atlantic salmon smolts from two Norwegian federal salmon hatcheries into rivers in 

Norway was responsible for the introduction of the freshwater parasite Gyrodactylus salaris, 

which caused the extirpation of Atlantic salmon in many river systems (Johnsen and Jensen 

1986, 1988). The viral disease infectious hematopoietic necrosis, ubiquitous in Alaska, British 

Columbia, and Washington sockeye salmon populations (Meyer et al. 1983), was introduced to 

Japan from a shipment of infected sockeye salmon eggs from a hatchery in Alaska and 

subsequently caused epizootic mortality in Japanese chum salmon and in two species of 

landlocked salmon which occur only in Japan (McDaniel et al. 1994). In these two cases, the 

indigenous salmonids in Norway and Japan were exposed to novel pathogens to which they had 

little or no immunity. In Washington, where no new stocks of Atlantic salmon have been 

introduced since 1991, the pathogens found in cultured salmonids are the same as those known to 

occur in wild salmon (Amos and Appleby 1999). 

Recently, significantly higher infestation rates by the copepod parasite Lepeophtherius 

salmonis was found on wild salmonids in Irish bays containing L. salmonis-infected farmed 

salmon than in bays where infected farmed salmon were not present (Tully et al. 1999). It 

appears that salmon farms in Ireland acted as a biomagnifier for this particular organism. Sea 

lice have also been observed on salmon from farms in British Columbia (Kent and Poppe 1998). 

However, L. salmonis has not been reported to be a significant problem in marine net-pens in 

Puget Sound (K. Amos8

). For example, since 1969, rainbow and cutthroat trout, and coho, 

chum, chinook, sockeye, pink, and Atlantic salmon have been grown in government and private 

net-pens in Clam Bay, Washington. L. salmonis, although commonly observed on captive fish in 

the net-pens, has not been a serious problem at the NMFS Manchester Research Station (L. 

Harrell9

), despite the fact that the fish in the pens experienced a high rearing density (number of 

fish per unit space) relative to densities experienced by free-swimming fish. High rearing 

density is thought to be primarily responsible for the greater incidences of fish diseases observed 

in hatchery salmon versus wild salmon (Wood 1979, Leitritz and Lewis 1980, Foott and Walker 

1992, Kent and Poppe 1998). 

 

8

 K. Amos, NMFS, 510 Desmond Dr. SW, Lacey, WA 98503. Pers. commun., March 27, 2002. 9

 L. Harrell, NMFS, P.O. Box 130, Manchester, WA 98353. Pers. commun., March 27, 2002. 
28

Diseases of Atlantic Salmon in the Pacific Northwest 

Alexandra Morton, director of Raincoast Research (PSGA 2000), and Peter Knutson, 

commissioner of the Puget Sound Gillnetters Association (Carrel 1998), asserted that Atlantic 

salmon in the Pacific Northwest are more likely to carry diseases than hatchery stocks of Pacific 

salmon, but these statements were not accompanied by a review of the scientific literature. 

Salmonids, including Atlantic salmon, can only carry diseases to which they have been exposed. 

The New England Atlantic salmon stocks used by Washington growers were certified by federal 

pathologists to be disease-free prior to shipment from East Coast hatcheries between 1980 and 

1986 and have been reared exclusively in the Pacific Northwest for many generations. Their 

diseases, if any, would be no different than the diseases found in nearby Pacific salmon 

hatcheries. In addition, Washington regulations require that all broodstocks of hatchery salmon, 

including Atlantic salmon broodstocks, must be examined for pathogens each year (Washington 

Administrative Code 220-77; Revised Code of Washington 75.58). Nonindigenous salmon 

diseases transmitted into the Pacific Northwest by the North American hatchery stocks of 

Atlantic salmon used in Washington have never been observed in the yearly sampling of these 

stocks since the mid-1970s. 

Potential for Disease Transmission from Atlantic Salmon to Pacific Salmon 

Pacific salmonids do not appear to be put to any increase in disease incidence when 

continually exposed to water in which Atlantic salmon have been reared. For example, Rocky 

Ford Creek, near Ephrata in eastern Washington, is considered to be one of the premier trout 

streams in the State (Northwest Fishing Holes 2001), yet the entire flow in this stream consists of 

effluent from an Atlantic salmon hatchery and smolt production facility (J. Parsons10). There are 

no reports of diseased trout in this stream in either the scientific literature or in the many media 

reports on the fine fishing in this stream. 

There is no evidence that hatchery-reared Atlantic salmon have introduced or spread 

nonindigenous diseases to native fishes in Washington (Amos and Appleby 1999). By law, 

privately owned Atlantic salmon populations in Washington are examined for diseases every 

year (WAC 220-77-030), and no exotic pathogens have been reported. With Pacific salmonids, 

Griffiths (1983) observed that outbreaks of serious contagious diseases were normally associated 

with the intensive culture of fish in a hatchery environment. Documentation of disease 

introductions in North America from the stocking or escape of artificially propagated salmonids 

has been uncommon (Krueger and May 1991). 

The Scale of Artificial Propagation of Salmon in the Pacific Northwest and 

Disease Transmission Potential 

Based solely on the enormous number of hatchery-reared salmonids released into rivers 

and lakes in the Pacific Northwest, the potential for transmission of disease to wild stocks from 

hatchery-reared Pacific salmon and trout would be greater than that of accidentally escaped 

farmed Atlantic salmon and rainbow trout in Washington State, although this statement is not 

 

10 J. Parsons, Troutlodge, Inc., P.O. Box 1290, Sumner, WA 98390. Pers. commun., March 12, 1999. 
29

meant to suggest that the risk from Pacific salmon hatcheries is severe or even moderate. 

However, escaped farmed Atlantic salmon and rainbow trout constitute a miniscule percentage 

of all artificially propagated salmon which end up in natural waters in the area. Furthermore, 

hatchery Pacific salmon occupying the marine waters of Washington each year have not been 

shown to impose adverse disease impacts on wild salmonids. Peter Knutson (Carrel 1998) 

described escaped Atlantic salmon as “smart bombs, delivering disease right into the bedrooms 

of wild salmon” in the Pacific Northwest, but this declaration has not been supported by the 

scientific literature. 

Mahnken et al. (1998) reported that since 1980 the number of Pacific salmon released 

from several hundred federal, state, tribal, and cooperative hatcheries on the West Coast was 

about 2 billion fish annually, which is about 30,000 to 40,000 times more than the number of 

Atlantic salmon that may have escaped from net-pens since 1980 (Table 5). 

On a smaller scale, the number of Pacific salmon released from saltwater net-pens in 

Puget Sound is much greater than the number of Atlantic salmon that escape from salmon farms. 

For example, NRC (1995, 1996) reported that coho salmon were released annually from 18 

different marine net-pen sites, chinook salmon from 13 different sites, and chum salmon from 10 

different sites in Puget Sound between Olympia and Bellingham. The number of fish released 

from these marine sites averaged about 10 million annually between 1980 and 1992. Currently, 

however, only about half that number are being released, due to dramatic changes in hatchery 

practices meant to protect wild salmonids in Puget Sound and Hood Canal (NWIFC 2001, 

WDFW 2000). These hatchery fish had sometimes been exposed to various salmonid pathogens 

before transfer to or while in seawater, including bacterial kidney disease, vibriosis, and 

furunculosis. Infections in these fish were often treated with antibiotics (PNWFHPC 1988a-d). 

Adverse disease impacts on wild salmonids were not reported during the rearing period or after 

they were released, nor were any media reports seen expressing concern that these fish may have 

been treated with antibiotics sometime prior to release into public waters. 

Disease Control Policies in Washington and the United States 

In Washington all public and private growers of salmon, including Atlantic salmon 

hatchery operators, are required to adhere to strict disease control polices that regulate all phases 

of fish culture, from egg take to harvest and release (NWIFC/WDF 1991, NWIFC/WDFW1998). 

Each year at spawning time, adult salmon at public and private hatcheries must be sampled for 

viral, bacterial, and parasitic organisms. If any of several reportable organisms are detected in 

fish at a hatchery or have been detected within the past five years, transfer of eggs or fish from 

that facility is prohibited, thereby significantly reducing the risk of diseases transfer from one 

location to another. 

The movement of fish and eggs across state or international borders is regulated by the 

USFWS under Title 50 of the CFR, which has stipulations and controls in accord with state 

regulations (50 CFR 16.13). For the case in point, all Atlantic salmon stocks distributed to local 

growers by NMFS were certified by federal pathologists before transfer from New England, and 

have been annually certified since then under Washington guidelines and procedures. 
30

Table 5. Number (in millions) of salmon released or escaped by species and location along the West 

Coast of North America, 1980-1995. (Data from Amos and Appleby 1999, Mahnken et al. 1998, 

Thomson and McKinnell 1993, 1994, 1995, 1996, 1997, Thomson and Candy 1998.) 

State or 

region 

Atlantic Sockeye Chum Steelhead Pink Coho Chinook

Alaska 0.0 978 3,885 2 8,610 193 98 

BC, Canada ~0.4 3,930 2,870 17 533 300 721 

Pacific Northwest ~0.6 52 1,081 359 21 1,726 4,320 

Total No. ~1.0 4,960 7,836 377 9,164 2,219 5,139 

Total % 0.0003 16.7 26.4 1.2 30.9 7.5 17.3 
31

POTENTIAL ECOLOGICAL IMPACTS OF ATLANTIC 

SALMON IN THE PACIFIC NORTHWEST 

Impacts of Cultured Atlantic Salmon on Wild Atlantic Salmon 

In areas where Atlantic salmon are indigenous, such as Scandinavia, Great Britain, and 

eastern North America, adverse genetic and ecological impacts for natural populations of 

Atlantic salmon have been reported following programmed releases or unintentional escapes of 

artificially propagated Atlantic salmon from public hatcheries and private net-pens (Hearn and 

Kynard 1986, Beall et al. 1989, Jones and Stanfield 1993, Heggberget et al. 1993, Gross 1998). 

The impacts included reductions in the genetic diversity and capacity to evolve in wild Atlantic 

salmon, introduction of genetic maladaptations as a result of interbreeding with artificially 

propagated Atlantic salmon, and competition for food and space between wild and hatchery 

stocks of Atlantic salmon. 

These particular adverse effects occurred because the artificially propagated and wild 

salmonid species were both Atlantic salmon. Escaped Atlantic salmon on the Pacific coast of 

North America do not have conspecific or congeneric wild individuals with which to interact. 

However, adverse ecological effects may still occur between different species. For example, 

introductions of hatchery coho salmon juveniles in western Washington appear to have had a 

negative impact on the abundance of wild cutthroat trout in some streams (Johnson et al. 1999). 

Actual negative ecological consequences for Pacific salmon and trout related to the deliberate or 

unintentional introduction of Atlantic salmon into their habitats have not been reported. In the 

Pacific Northwest region, introductions and transfers of hatchery stocks of Pacific salmon, rather 

than escapes of Atlantic salmon, have much greater potential to produce impacts on native 

Pacific salmon analogous to those found between propagated and wild Atlantic salmon in Europe 

and eastern North America. 

Impacts of Cultured Pacific Salmon on Wild Pacific Salmon 

Many adverse genetic and ecological interactions on local wild salmon populations 

resulting from plants of artificially propagated Pacific salmonids have been documented in the 

Pacific Northwest (Campton and Johnston 1985, Nicholson et al. 1986, Leider et al. 1987, 

Behnke 1992, WDF et al. 1993, Kostow 1995). These adverse impacts in part include 

introgressive hybridization, competition for food and rearing space, decreased effective 

population size, decreased reproductive success, and reductions in intraspecific diversity. 

Recently, significant changes in management strategies by resource agencies have been initiated 

to reduce or eliminate adverse impacts from traditional hatchery programs, such as stock transfer 

guidelines used by WDFW for the last decade (WDF 1991a). No reports of detrimental impacts 

in the Puget Sound or Hood Canal ESUs related to deliberate or accidental Atlantic salmon 

introductions have been found. 
32

Ecological Interactions between Atlantic Salmon and Pacific Salmon 

Behavioral Interactions 

Gibson (1981) reported that in laboratory studies in New England, introduced Pacific 

steelhead juveniles were more aggressive than Atlantic salmon. In turn, Atlantic salmon fry 

appeared to be more aggressive than coho salmon fry when introduced into open pools, although 

it was recognized that open pools are not the preferred habitat of coho salmon fry. In a similar 

experiment, Beall et al. (1989) reported that the survival of Atlantic salmon was reduced in the 

presence of older coho salmon fry. 

In trials of interspecific combative behavior in a small river in New England, Hearn and 

Kynard (1986) observed that rainbow trout juveniles initiated three to four times more aggressive 

encounters than did Atlantic salmon, and concluded that it would take very large numbers of 

Atlantic salmon juveniles to displace or even disrupt rainbow trout. Jones and Stanfield (1993), 

in a study conducted in a Lake Ontario tributary once inhabited by Atlantic salmon, reported that 

their attempts to reintroduce hatchery strains of Atlantic salmon were significantly impaired in 

the presence of naturalized Pacific salmon juveniles, compared with reintroduction in stream 

sections where Pacific salmon juveniles had been removed. Volpe et al. (2001) observed that in 

an artificial environment, territory was successfully defended by the initial resident, whether that 

was an Atlantic salmon or a steelhead, which had been reared to achieve a standardized size prior 

to the study. It was speculated that the potentially greater size-at-age of naturally produced 

Atlantic salmon (Volpe et al. 2000) might give them a greater advantage. 

Predation by Atlantic Salmon 

In a study on farmed fish in British Columbia by Black et al. (1992), stomach analyses 

revealed that less than 1% of farmed salmon in net-pens (in this case coho and chinook salmon) 

contained the remains of fish. Since 1992 Canadian government scientists have examined the 

stomach contents of escaped Atlantic salmon recovered in the open waters of British Columbia 

as part of the Atlantic Salmon Watch Program in the province. Fish remains of any sort were 

rarely observed, and to date, the remains of just a few Pacific salmon (chum salmon) have been 

observed, in this case, in the stomach of a hatchery Atlantic salmon juvenile in Carnation Creek, 

British Columbia (Thomson and McKinnell 1993, 1994, 1995, 1996, 1997, Thomson and Candy 

1998; A. Thomson11). That only a few juvenile salmonids have been observed in the stomachs 

of escaped Atlantic salmon (over 1,000 stomachs examined in British Columbia and Alaska) 

indicates that these fish have a very low propensity to prey on juvenile salmonids, compared to 

Pacific salmon. For example, Fresh (1997) compiled information showing that about 50% of 

chum salmon juveniles are consumed by various predators, including other salmon, during their 

short period of migration from freshwater to marine environments. In the Chignik Lakes of 

Alaska, Ruggerone and Rodgers (1992) observed that juvenile coho salmon ate almost 60% of 

the sockeye salmon fry population. Fresh (1997) indicated that 33 fish species, 13 bird species, 

and 16 marine mammal species are predators of juvenile and adult Pacific salmon. Tynan (1981) 

 

11 A. Thomson, DFO Canada, Pacific Biological Station, Nanaimo, BC V9R 5K6. Pers. commun., December 27, 

2001. 
33

examined the stomachs of 93 coho salmon post-smolts captured after release from a net-pen near 

Squaxin Island, in South Puget Sound, and reported that only 3 stomachs contained fish remains, 

which were identified as smelt (Hypomesus pretiosus). 

At the NMFS Manchester Research Station in Puget Sound, many species of forage fish 

have been observed seeking refuge from predators in net-pens containing adult Atlantic salmon. 

Among the species observed are known prey of salmonids, such as herring (Clupea pallasi), 

smelt, sand lance (Ammodytes hexapterus), shiner perch (Cymatogaster aggregata), and tube 

snouts (Aulorhynchus flavidus). These prey species voluntarily enter the net-pens through the 

mesh and then grow too large to exit. Alverson and Ruggerone (1997) noted that many 

thousands of these small fish had been observed in Atlantic salmon net-pens, and eventually had 

to be removed by hand. 

Buckley (1999) observed that cannibalism and predation by chinook salmon on other 

salmonids was uncommon in Puget Sound waters. It is difficult to imagine that escaped Atlantic 

salmon, conditioned to a diet of artificial feed pellets and trained to be fed by humans, could 

have greater predation impacts on juvenile native salmonids than the impacts observed with freeswimming Puget Sound chinook and coho salmon. 

Predation by Introduced Brown Trout 

In the Cowichan River in British Columbia, non-native brown trout became established 

soon after the first introduction in 1932. Idyll (1942) observed that native salmon, trout, and 

their eggs, were a significant dietary component of young Cowichan River brown trout, and were 

the primary food item of large brown trout, as they were found to be elsewhere (Krueger and 

May 1991). Recent evaluations by Wightman et al. (1998) of steelhead populations on the east 

coast of Vancouver Island showed that the Cowichan River was one of only two rivers (out of 27 

evaluated) with a relatively healthy steelhead population. Therefore, the successful colonization 

of the Cowichan River by a highly piscivorous species such as the brown trout has apparently 

had little or no adverse impact on steelhead abundance for more than 60 years, whereas attempts 

to establish Atlantic salmon in the Cowichan River Basin were failures. No media reports 

deploring the establishment of predatory brown trout in the Cowichan River were found in this 

review. On the contrary, the fact that large brown trout established in the Cowichan River 

compete with and prey on native salmon and trout was described, simply, as “browns will be 

browns” (Marsh 2000). Self-sustaining populations of predacious brown trout do not appear to 

be a cause for concern for citizens in the Pacific Northwest. However, the presence of a small 

number of Atlantic salmon juveniles in Vancouver Island streams has been viewed with alarm. 

These concerns can be summarized by statements such as John Volpe’s that “steelhead will 

likely suffer most” from the presence of Atlantic salmon in these streams (Marsh 1999); Barbara 

Stenson’s that “the possibility of farmed salmon interbreeding with Pacific salmon has been 

confirmed in laboratory tests” (1998); and that of Jim Fulton, executive director of the David 

Suzuki Foundation, that successful Atlantic salmon reproduction will be “the wave of death” for 

native salmon stocks (Howard 1999). 
34

Ecological Interactions between Cultured Pacific Salmon and Wild 

Pacific Salmon 

Adverse genetic and ecological effects from artificially propagated Pacific salmon have 

been documented by Weitkamp et al. (1995), Busby et al. (1996), Hard et al. (1996), Gustafson 

et al. (1997), Johnson et al. (1997, 1999), and Myers et al. (1998a) in coast-wide status reviews 

of Pacific salmonids conducted by NMFS in fulfillment of its responsibilities under ESA. The 

reviews contained information from the scientific literature that documented known adverse 

ecological impacts sometimes associated with the artificial propagation and release of Pacific 

salmon on the West Coast. In recent years, however, concerned management agencies have 

eliminated or modified many of the policies that contributed to these adverse effects. 

Nevertheless, examining known adverse impacts of Pacific salmon hatchery programs offers an 

effective demonstration that, by comparison, the ecological and genetic risks associated with 

Atlantic salmon farming are very small for federally listed chinook and summer-run chum 

salmon, as well as for other species, in Puget Sound and Hood Canal. The following paragraphs 

provide a brief review, by species, of adverse effects of artificial propagation that occurred 

before some of the Pacific salmon hatchery strategies that contributed to these effects were 

modified or eliminated. 

Chinook Salmon 

About 1.77 billion hatchery chinook salmon have been released into Puget Sound and its 

tributaries between 1953 and 1993, which is about 84 million per year, with the stock from the 

Green River Hatchery being the dominant stock as far back as 1907 (Myers et al. 1998a). 

Concerns that this strategy may have eroded genetic diversity were raised by Myers et al. 

(1998a). As recently as 1995, 20 hatcheries and 10 marine net-pen sites throughout Puget Sound 

regularly released Green River-stock chinook salmon, although most marine releases of chinook 

salmon in Puget Sound have been terminated (NWIFC 2001). Busack and Marshall (1995) 

reported that the extensive use of this stock had an undoubted impact on among-stock diversity 

within WDFW’s South Puget Sound, Hood Canal, and Snohomish summer/fall chinook salmon 

genetic diversity unit (GDU), and may also have impacted GDUs elsewhere in Puget Sound and 

the Strait of Juan de Fuca. A GDU is defined as: “a group of genetically similar stocks that is 

genetically distinct from other such groups. The stocks typically exhibit similar life histories and 

occupy ecologically, geographically, and geologically similar habitats. A GDU may consist of a 

single stock” (Busack and Marshall 1995). Generally, GDUs delineate stocks at a finer scale 

than the NMFS criteria for ESUs. For example, the single NMFS ESU for Puget Sound chinook 

salmon includes 6 WDFW GDUs (Busack and Marshall 1995). 

Rogue River chinook salmon have recently been released on the Oregon side of the 

Lower Columbia River to produce a south-migrating stock to avoid interception in commercial 

fisheries in British Columbia and southeast Alaska. Consequently, chinook salmon exhibiting 

Rogue River fall chinook salmon genetic markers were subsequently observed in about 13% of 

naturally produced chinook salmon juveniles in several lower Columbia River tributaries 

(Marshall 1997). In addition, most of the naturally spawning spring chinook salmon in Lower 

Columbia River tributaries were already hatchery strays (Marshall et al. 1995). Adverse impacts 
35

resulting from the introduction of artificially propagated fish into native populations of chinook 

salmon were identified as a primary concern by the NMFS Biological Review Team(BRT) for 

ESA Status Review during the recent review of the status of West Coast chinook salmon 

populations (Myers et al. 1998a). There is no evidence of similar adverse effects on chinook 

salmon resulting from escaped Atlantic salmon in Washington or elsewhere within the original 

and naturalized (introduced) range of chinook salmon. 

Chum Salmon 

Johnson et al. (1997) reported that five hatchery stocks and several wild populations of 

chum salmon outside Hood Canal that were enhanced with eggs from Hood Canal hatcheries for 

several years subsequently exhibited genetic profiles more similar to those in Hood Canal 

hatchery populations than to populations in nearby streams that did not receive Hood Canal 

hatchery stock. Analyses of genetic profiles were consistent with the hypothesis that egg 

transfers between hatcheries and out-plantings of Hood Canal stock fry had genetically 

influenced the receiving populations. As a result, such transfers were terminated because of the 

potential jeopardy to wild gene pools through interbreeding (Phelps et al. 1995). 

Steelhead Trout 

Hatchery stocks of steelhead have been widely distributed. Few native steelhead stocks 

exist in the contiguous United States that have not had some influence from hatchery operations. 

For example, the summer steelhead program at the Nimbus Hatchery in Central Valley, 

California, was established with fish from a distant coastal tributary hatchery, which was itself 

earlier established with Lower Columbia River summer steelhead (Busby et al. 1996). 

Howell et al. (1985) reported that over 90% of the “wild” steelhead spawning in the 

Cowlitz River originated in a hatchery, and some of these fish exhibited genetic characteristics 

(chromosome number) of Puget Sound steelhead due to previous transfers of Puget Sound stock 

to the Cowlitz Hatchery. Chilcote (1997) reported that since 1980 the percentage of non-native 

hatchery steelhead (from upper Columbia River and Snake River hatcheries) spawning in the 

Deschutes River had increased to over 70% of the run, while the percentage of native, wild 

steelhead spawning in the Deschutes River decreased to less than 15%. Phelps et al. (1997) 

postulated that introductions of non-native steelhead stocks in Washington, primarily Chambers 

Creek winter steelhead and Wells and Skamania summer steelhead, may have changed the 

genetic characteristics of some Puget Sound and eastern Washington steelhead populations 

sufficiently so that the original genetic relationships between stocks may have been obscured. 

Leider et al. (1987) concluded that the genetic fitness of the wild Kalama River population had 

been compromised by maladaptive gene flow from excess hatchery escapement. By comparison, 

no adverse effects on steelhead have been reported as a result of escapes of Atlantic salmon in 

Washington or elsewhere within the original and naturalized (introduced) range of steelhead. 

Coho Salmon 

Weitkamp et al. (1995) noted that it was extremely difficult for the NMFS BRT for ESA 

Status Review to identify any remaining natural populations of coho salmon in the Lower 
36

Columbia River below Bonneville Dam, due in large part to persistent and extensive hatchery 

programs. A recent survey by NRC (1999) of coho salmon spawning habitat in the Lower 

Columbia River estimated that about 97% of recovered spawned-out carcasses originated from 

hatchery releases. Hatchery fish were observed in high percentages in streams up to 45 miles 

from the nearest hatchery. In many streams, wild coho salmon were not observed at all. In an 

earlier survey in Hood Canal, over 50% of all spawning coho salmon in streams within a 10-mile 

radius of a net-pen release site were fish originally released from the net-pen as juveniles 18 

months earlier (NRC 1997). 

Kostow (1995) stated that hatchery programs in Oregon may have contributed to the 

decline of wild coho salmon by supporting harvest rates in mixed-stock fisheries that were 

excessive for sustained wild fish production, and by reducing the fitness of wild populations 

through interbreeding between hatchery and wild fish. Furthermore, hatchery fish may have 

reduced survival of wild coho salmon juveniles in Oregon through increased competition for 

food in streams and estuaries, attraction of predators during mass migrations, and initiation of 

disease problems. 

Weitkamp et al. (1995) also reported that artificial propagation of coho salmon appeared 

to have had substantial impact on native coho salmon populations to the point where it was 

difficult for the NMFS BRT for ESA Status Review to identify self-sustaining native stocks in 

Puget Sound, as over half the returning spawners originated in hatcheries. Spawn timing had 

been advanced by selective breeding to allow hatcheries to meet their quotas for eggs by early 

November. Fish arriving at the hatchery with the later part of the run (which would be 

coincidental with the spawn time of the majority of wild or native fish) were not propagated. As 

a result of such practices, segments of hatchery coho salmon populations which historically 

returned as late as January through March have disappeared from many river systems, resulting 

in a significant loss of life-history diversity (Flagg et al. 1995). Regarding speculation that small 

pockets of self-sustaining wild coho salmon populations that have had no hatchery influence 

might remain in any tributary in Washington State, WDF (1991b) stated: “To assume there are, 

given the record, would seem to be a most notable defiance of the odds.” There is no 

documented evidence of similar adverse effects on coho salmon resulting from escaped Atlantic 

salmon. 

Pacific Trout 

Long-term introductions of rainbow trout into western streams originally inhabited only 

by cutthroat trout have resulted in widespread extinction of native cutthroat trout through 

introgressive hybridization (Leary et al. 1995). Most of the rainbow trout released into Pacific 

Northwest lakes are derived from California strains, which have a different number of 

chromosomes than the rainbow trout native to many Puget Sound watersheds (Busby et al. 

1996). Genetic analysis has shown the California-strain rainbow trout to be dramatically 

different than local strains (Busby et al. 1996). Hybridization between introduced brook trout 

and native bull trout (Salvelinus confluentus) is widespread in the western United States and 

usually produces sterile hybrids (Behnke 1992). Behnke (1992) noted that introduced brown 

trout had commonly replaced interior subspecies of cutthroat trout in large streams throughout 
37

the same region, and introduced brook trout were the most common trout to be found in some 

small streams. 

The situation regarding attempts to establish Atlantic salmon populations west of the 

Mississippi River is much different. In summary, MacCrimmon and Gots (1979) described 

frequent attempts (all failures) to introduce Atlantic salmon to western states, many of which 

occurred in the same river systems and at the same time as the successful trout introductions 

noted above. Since MacCrimmon and Gots (1979), no recent introductions, accidental or not, 

have succeeded and, most importantly, no known adverse impacts on Puget Sound trout by 

Atlantic salmon have been reported in the literature. 
38
39

ADVERSE IMPACTS OF NONINDIGENOUS FISH 

INTRODUCTIONS 

In contrast to the situation with Atlantic salmon, as many as 50 species of non-native fish 

are successfully established in the western United States (Table 6). Some adverse impacts 

associated with the establishment of these species are discussed below. 

ODFW/NMFS (1998) documented that many introduced non-native species were 

harmful to native salmon. For example, walleye (Stizostedion vitreum), bass, perch (Perca 

flavescens), sunfish (Lepomis sp.), brown trout, and brook trout, among others, are well-known 

predators or competitors of native salmon and trout and all have now been successfully 

established in Northwest waters. Beamesderfer and Nigro (1988) and Beamesderfer and Ward 

(1994) estimated that walleye and smallmouth bass (Micropterus dolomieu) introduced into the 

Columbia River consumed an average of 400,000 and 230,000 juvenile salmonids, respectively, 

each year in the John Day Reservoir. Daily et al. (1999) reported that juvenile salmonids from 7 

ESUs currently listed as threatened or endangered under ESA must migrate through the John 

Day Reservoir. 

In some coastal lakes in Oregon, the summer rearing of coho salmon fry no longer occurs 

due to predation by introduced largemouth bass (Micropterus salmoides) (Daily et al. 1999). 

Tabor et al. (2000) observed that introduced largemouth and smallmouth bass eat out-migrating 

salmon, including juvenile chinook salmon, as they pass through the Lake Washington Ship 

Canal in Seattle, Washington. From April through July, juvenile chinook salmon constituted 

about 50% of the stomach contents of smallmouth bass in the Ship Canal. As many as 100,000 

juvenile chinook salmon, some of which are hatchery fish, may be consumed in the Ship Canal 

during the 90 day out-migration period, which may pose a significant threat to juvenile chinook 

salmon migrating from the Lake Washington system (City of Bellevue 2002). By comparison, 

there is no documented literature which shows that escaped Atlantic salmon are a significant 

predator of juvenile native salmonids in the Pacific Northwest. Of the over 1,000 feral Atlantic 

salmon examined to date in Alaska and British Columbia, only one was found to have consumed 

a Pacific salmon juvenile (see Predation by Atlantic Salmon subsection above). 
40

Table 6. Status of non-native fish introductions in the Pacific Northwest and their behavior relative to 

Pacific salmonids. (Data after Behnke 1992, Lever 1996, Daily et al. 1999, WDFW 1999, 

Wydoski and Whitney 1979, Dill and Cordone 1997.) 

Non-native species 

Naturalized in 

Washington 

Naturalized in 

Oregon 

Naturalized in 

California Predator Competitor Hybridize

Atlantic salmon 

Non-native rainbow X X X X X X 

Non-native cutthroat X X X X X X 

Lahotan cutthroat X X 

Westslope cutthroat X X X X 

Brown trout X X X X X X 

Brook trout X X X X X X 

Lake trout X X X X X 

American shad X X X X 

Threadfin shad X 

Lake whitefish X 

Arctic grayling X X 

Grass pickerel X X 

Northern pike X X X 

Striped bass X X X 

White bass X 

Common carp X X X X 

Grass carp X X 

Tench X X 

Brown bullhead X X X X X 

Black bullhead X X X X X 

Yellow bullhead X X X X X 

Flathead catfish X X X X 

Blue catfish X X X 

Channel catfish X X X X X 

White catfish X X X X 

Largemouth bass X X X X X 

Smallmouth bass X X X X X 

Warmouth bass X X X X X 

Rock bass X X X 

Redeye bass X 

Northern spotted bass X 

Alabama spotted bass X 

Black crappie X X X X X 

White crappie X X X X X 

Green sunfish X X X X X 

Bluegill X X X X X 

Pumpkinseed X X X X X 

Redear sunfish X 

Bigscale logperch X 

Yellow perch X X X X X 

Walleye X X X X X 
41

MANAGEMENT OF NONINDIGENOUS FISH IN 

WASHINGTON 

In 1997 and 1999, in response to the escape of a large number of net-pen Atlantic salmon, 

WDFW suspended fishing regulations concerning size and bag limits for these fish. Licensed 

anglers fishing in open management zones were permitted to keep all the Atlantic salmon they 

could catch, of whatever size (WDFW 1997, 1999, 2002). The suspension of fishing regulations 

for an introduced, non-native species in waters inhabited by native salmonids is a management 

strategy that has been used before in Washington. For example, freshwater angling regulations 

for non-native brook trout were recently relaxed to increase harvest of this species, and 

regulations for non-native shad (Alosa sapidissima), perch, crappie (Pomoxis nigromaculatus), 

bluegill (Lepomis macrochirus), and carp (Cyprinus carpio) have long since been dismissed 

entirely. Harvest policies of this type would likely reduce, but not eliminate, known impacts of 

non-native species on listed salmonids in the two Puget Sound ESUs that are the subject of this 

review. However, regulations currently applied to some non-native species (see next paragraph), 

such as those that encourage their sustained natural reproduction, may not reduce but actually 

increase the impacts of non-native species on listed salmonids. 

Catch limits and closed seasons for non-native salmonids (such as brown trout, lake trout, 

landlocked Atlantic salmon, California-strain rainbow trout, and grayling) in watersheds within 

the Puget Sound and Hood Canal ESUs for chinook salmon and summer-run chum have given 

these species many of the same statutory protections given to native salmonids. Several nonnative warm-water species known to prey on salmonid juveniles in Washington (such as 

smallmouth and largemouth bass, walleye, and channel catfish [Ictalurus punctatus]) are 

currently managed for sustained natural reproduction through regulations that limit the take of 

large individuals, which have the greatest reproductive potential (WDFW 2002). Although 

walleye and channel catfish are found primarily in the Columbia River, largemouth and 

smallmouth bass populations in dozens of Puget Sound area tributary systems are regulated to 

insure their continued survival. As shown in this review, Atlantic salmon have far less potential 

for adverse impacts on Puget Sound chinook salmon and Hood Canal summer-run chum salmon 

than the non-native species noted here. Extending management policies currently applied to 

escaped Atlantic salmon (no catch or size limits) to all non-native fish in Puget Sound would be 

the most effective method to decrease adverse impacts by nonindigenous fish on listed native 

Puget Sound salmonids. However, this is probably not feasible due to the tremendous economic 

and social value of non-native game fish species in local sport fisheries. Zook (1998) estimated 

that recreational angling for non-native game fish, including California-strain rainbow trout, 

contributed about $735 million annually to the economy in Washington State. 
42
43

SCALE OF ARTIFICIAL PROPAGATION OF PACIFIC 

SALMON IN THE PACIFIC NORTHWEST 

Virtually all opinions about the negative biological impacts of escaped Atlantic salmon 

on native salmon in the Pacific Northwest are hypothetical, and have not been observed or 

documented in this region. They appear to be strongly associated with the belief that artificially 

propagated salmon, including Atlantic salmon, are bigger, stronger, and more vigorous than wild 

Pacific salmon. Although this opinion has been generally disproved, many studies and reviews, 

among them WDF et al. (1993) and NMFS’ ESA-related status reviews (Weitkamp et al. 1995, 

Busby et al. 1996, Hard et al. 1996, Gustafson et al. 1997, Johnson et al. 1997, 1999, Myers et al. 

1998a), have shown that adverse impacts from hatchery stocks of Pacific salmon can occur if and 

when hatchery fish comprise a significant portion of the total population. Therefore, it will be 

instructive to compare the numbers of artificially propagated Pacific salmon released each year 

to the number of Atlantic salmon estimated to escape each year. Such comparison will provide a 

perspective for evaluating which species or types of culture actually present the greatest risks to 

wild Pacific salmon, keeping in mind that recent changes in hatcheries strategies in the Pacific 

Northwest have been initiated to reduce or eliminate impacts sometimes associated with releases 

of artificially propagated Pacific salmon. 

Number of Artificially Propagated Pacific Salmon Released Each 

Year 

Mahnken et al. (1998) reported that several billion Pacific salmon were released from 

freshwater hatcheries and marine net-pens in North America each year, with most of these fish 

(about 1.4 billion per year) released from hatcheries in Alaska (McNair 1997, 1998, 1999) (see 

Table 5), although Washington, Oregon, Idaho, and California have more salmon hatcheries. 

Pacific salmon are released from hatcheries with the understanding that to survive, they 

must compete for food and habitat in common with native wild salmon. Until recently the 

capacity of the ocean pastures were thought to be limitless. However, recent investigations by 

Heard (1998), Cooney and Brodeur (1998), and Beamish et al. (2000), among others, show that 

food availability in the ocean fluctuates over time and might be limiting salmon abundance. 

Bisbal and McConnaha (1998) proposed that fishery managers planning to release large numbers 

of fish from hatcheries should take these fluctuations into account. Given the enormous numbers 

of Pacific salmonids released each year into Pacific Ocean ecosystems, including Puget Sound, 

the relatively few domesticated Atlantic salmon that escape could never pose a corresponding 

competitive threat to native Pacific salmon for forage or habitat. 

Survival of Artificially Propagated Pacific Salmon 

The success of a hatchery or net-pen facility, which in large part determines the degree to 

which hatchery fish potentially impact wild fish, is largely influenced by how well fish survive in 
44

the wild after release. Some hatchery programs are very successful at producing fish. Johnson et 

al. (1997) noted that hatcheries in Alaska, through extremely efficient early rearing strategies, 

produced prodigious numbers of adult chum and pink salmon, two species which normally have 

juvenile to adult survival rates of less than 0.5%. The Hidden Falls Hatchery in southeast Alaska 

has frequently experienced survivals of 3–8% with chum salmon (Bachen 1994), resulting in this 

single facility producing more than 22% of all the chum salmon, wild and hatchery, caught in the 

fisheries of southeast Alaska (Johnson et al. 1997). McNair (1998) reported that 93.6% of all 

pink salmon caught in Prince William Sound in 1997 were artificially propagated, and that for all 

salmon harvested in common property fisheries throughout Alaska that year, 22% of the coho 

salmon, 30% of the pink salmon, and 65% of the chum salmon originated in hatcheries. Overall, 

hatcheries contributed 26% of all salmon harvested in Alaska in 1997 (McNair 1998). This 

percentage increased to 34% in 2000 (McNair 2001). In Washington, WDFW (2000) estimated 

that hatcheries provide about 75% of all coho and chinook salmon harvested, as well as 88% of 

all steelhead harvested. Since West Coast hatcheries put enough artificially propagated salmon 

into the natural environments to produce a significant proportion of the harvest in Alaska and the 

overwhelming proportion of the harvest in Washington, including all ESUs in Puget Sound and 

Hood Canal, it is not possible that the competition for natural resources from present levels of 

escaped Atlantic salmon could be noticeable. Therefore, expressions of concern regarding 

competition for food from relatively small numbers of escaped Atlantic salmon (Carrel 1998, 

ADF&G 1999, 2002, PSGA 2000, Suzuki 2001) appear to be focused on the wrong species. The 

potential for adverse impacts on wild Pacific salmon through competition for natural resources is 

clearly greater from the enormous number of hatchery Pacific salmon in natural environments 

than from the relatively small number of domesticated Atlantic salmon that occasionally escape. 

Comparison of Numbers of Artificially Propagated Atlantic Salmon 

and Pacific Salmon in the Pacific Northwest 

The majority of Atlantic salmon escapes in Washington have occurred in Puget Sound. 

However, the number of escaped fish is extremely low compared with the number of Pacific 

salmon intentionally introduced into the Puget Sound and Hood Canal ESUs for chinook and 

summer-run chum salmon. The total number of hatchery chinook, coho, and chum salmon 

released into Puget Sound tributaries by various fisheries agencies between 1980 and 1992 

exceeded 2.2 billion fish (NRC 1995, 1996). Although data are not yet available through the 

year 2001, it is predictably over 3 billion by now. For illustrative purposes, if all the Atlantic 

salmon which have escaped into Puget Sound since 1980 (assume 1 million) were represented on 

a bar graph by a bar about 3 cm high, the total number of Pacific salmon released into Puget 

Sound and its river basins since 1980 would be depicted on the same graph by a bar about 76 m 

high. Comparison with the 13.5 billion hatchery fish released into Alaskan waters since 1990 

(McKean 1991, McNair 1995, 1996, 1997, 1998, 1999, 2000, 2001, Holland and McKean 1992, 

McNair and Holland 1993, 1994) is even more dramatic, and would require a bar almost 400 m 

high. 

The adverse ecological and genetic interactions sometimes associated with abundant 

releases of hatchery-reared Pacific salmon are well-documented and clearly present a greater risk 

for native salmonids in Puget Sound and Hood Canal than escaped Atlantic salmon, although this 
45

is not meant to imply that the risk from hatchery stocks of Pacific salmon is severe under present, 

modified hatchery policies. However, no evidence in the literature pertaining to Atlantic salmon 

introductions was found that suggests that current levels of production would pose a manifest 

threat to the Puget Sound chinook salmon ESU or the Hood Canal summer-run chum salmon 

ESU. 
46
47

POTENTIAL IMPACT OF SUCCESSFULLY REPRODUCING 

ATLANTIC SALMON IN PUGET SOUND 

Number of Naturally Produced Juvenile Atlantic Salmon that 

Would Approximate Impacts from Pacific Salmon Hatchery 

Programs in Puget Sound 

It would take a very large number of successfully spawning, escaped Atlantic salmon to 

produce enough progeny to approach the number of hatchery Pacific salmon juveniles introduced 

into streams in the Puget Sound ESU. For example, NRC (1995, 1996) reported that about 18 

million pre-smolt coho salmon were released into Puget Sound tributaries each year between 

1980 and 1992. Since then, the number of unsmolted coho salmon has been reduced by over 

half, due to changes in hatchery strategies (FPC 1999). Nonetheless, to survive in freshwater 

habitats, artificially propagated salmon fry planted into local rivers compete with native salmon 

for food and rearing space for up to 18 months. Using typical wild coho salmon life-history data 

(ODFW 1982), such as egg to smolt survival levels of 10% and a fecundity of 4,000 eggs per 

female, it would take about 46,000 mature, successful Atlantic salmon spawners (1:1 

female:male ratio) to produce enough fry to equal the numbers of artificially propagated 

nonmigrant hatchery coho salmon planted in Puget Sound rivers every year. However, the 

likelihood of such an outcome is remote, given the well-documented negligible ability of 

introduced Atlantic salmon to prosper in habitats outside their native range. 

Number of Naturally Produced Juvenile Atlantic Salmon that 

Would Approximate Impacts from Pacific Salmon Hatchery 

Programs in the Green River 

On a more local scale, FPC (1999) reported that about 7,500,000 hatchery coho salmon 

fry were planted in the Green River between 1993 and 1996. To produce an equal number of 

Atlantic salmon juveniles, it would be necessary for over 9,000 mature Atlantic salmon adults to 

escape and spawn successfully in the Green River each year. However, Thomson and Candy 

(1998) reported fewer than 20 mature Atlantic salmon in all Washington river systems during 

1997, although few streams were surveyed completely. As Puget Sound region stocks of farmed 

Atlantic salmon continue to be domesticated, there is little chance they will suddenly outperform 

native salmon in their natal streams. Best management practices for net-pen salmon farming 

continue to stress the importance of preventing escapes (BCSFA 1999), but any potential adverse 

impacts associated with escaped Atlantic salmon cannot begin to approach the potential impacts 

of fish released from Pacific salmon hatchery programs, even when recent beneficial changes in 

hatchery strategies are considered. 
48

Number of Juvenile Atlantic Salmon Observed in the Pacific 

Northwest 

Fewer than 25 naturally spawned juvenile Atlantic salmon were recovered during counts 

of salmon juveniles in the Tsitika River in British Columbia in 1998 (A. Thomson12). Although 

scale analysis confirmed that these fish were the progeny of naturally spawning adult Atlantic 

salmon (Volpe et al. 2000), it is not known whether these were first, second, or greater 

generation wild Atlantic salmon. During the same Tsitika River survey, Noakes (1999) noted 

that more than 10,000 juvenile Pacific salmonids were observed in the river. Therefore, the 

juvenile Atlantic salmon made up less than 1% of the juvenile salmonids in the river in 1998. 

Since 1998, 5 more juvenile Atlantic salmon have been observed in the Tsitika River (A. 

Thomson12). Over 90% of all naturally produced Atlantic salmon juveniles discovered to date 

were found in 1998 and 1999. Interestingly, naturally produced Atlantic salmon juveniles were 

never observed in the same streams in which juvenile Atlantic salmon hatchery escapees were 

found (Table 3). 

It is possible that Atlantic salmon have been successfully spawning in the Pacific 

Northwest for the past 20 years and that this behavior has just recently been observed. 

Conversely, Atlantic salmon could be periodically introduced into local environments every so 

often via escaping adults without successfully colonizing new habitat, although naturally 

produced offspring may have been occasionally produced. In any event, no naturally produced 

Atlantic salmon have been observed in Washington rivers to date, although surveys specifically 

designed to find juvenile Atlantic salmon have not been conducted here, unlike the situation in 

British Columbia. 

 

12 A. Thomson, DFO Canada, Pacific Biological Station, Nanaimo, BC V9R 5K6. Pers. commun., April 16, 2001. 
49

OTHER EVALUATIONS OF POTENTIAL RISKS FROM 

CULTURED ATLANTIC SALMON IN PUGET SOUND 

CHINOOK SALMON AND HOOD CANAL SUMMER-RUN 

CHUM SALMON ESUS

Washington State Pollution Control Hearings Board 

In 1996, a consortium of organizations brought suit before the PCHB against the 

Washington State Department of Ecology (WDOE), WDFW, and Atlantic salmon farmers in 

Puget Sound. The suit (PCHB Nos. 96-257 through 96-268) challenged the issuance of National 

Pollutant Discharge Elimination System (NPDES) permits to the salmon farmers. The basis of 

the suit by the appellants was a series of allegations regarding conflict with other resources and 

perceived unacceptable environmental risks associated with the culture of Atlantic salmon, the 

effects of waste on the water column and benthic environment, and damage to other resources, 

including fish and shellfish. 

Following months of testimony by experts, on May 27, 1997, the PCHB denied partial 

summary judgment to the appellants because of a genuine issue of material fact as to whether 

escaped Atlantic salmon “shall cause or tend to cause pollution” under State law, and whether 

they constitute “a manmade change to the biological integrity of State water” under federal law 

(PCHB 1997b). The PCHB found that, “the Permittees’ facilities do not create unresolved 

conflicts with alternative uses of Puget Sound resources as contemplated by RCW 

43.32C.030(2)(e). The existence of commercial salmon farms as permitted does not preclude 

other beneficial uses in Puget Sound, such as shellfish harvesting, commercial or sport fishing, 

navigation, or recreational boating. Likewise, the existence of the salmon farms does not operate 

to the exclusion of available resources, such as native salmon runs, sediment and water quality, 

or marine mammals. In short, salmon farming in Puget Sound does not present the citizens of 

the State of Washington with an ‘either/or’ choice with respect to other beneficial uses and 

important resources.” 

The Board issued its Final Order on the matter on November 30, 1998, (PCHB 1998) and 

found: “no evidence that Permittees’ facilities have impacts that effectively exclude other 

beneficial uses of available resources of Puget Sound. The escapement of Atlantic salmon from 

Permittees’ facilities absent large regular releases in the future does not pose an unacceptable 

risk to native Pacific salmon in terms of competition, predation, disease transmission, 

hybridization, or colonization.” This decision by the PCHB was not substantially different from 

that of the authors of the British Columbia Salmon Aquaculture Review (EAO 1997), who 

concluded that salmon aquaculture as currently practiced in British Columbia did not pose 

unacceptable risks to the environment. 
50

Washington Department of Fish and Wildlife Atlantic Salmon 

Management Perspective 

Some fishery managers have expressed concerns that escaped Atlantic salmon may 

impact native fish stocks through “competition, predation, disease transfer, hybridization, and 

colonization” (summarized by Amos and Appleby 1999). In a review of the potential for adverse 

impacts on Pacific salmon from farmed Atlantic salmon, WDFW found there was no evidence 

that Atlantic salmon competed well against native species, or that they would prey on native 

species. Furthermore, WDFW recognized that diseases of Atlantic salmon in Puget Sound were 

the same as diseases of Pacific salmon, that the risk of Atlantic salmon hybridizing with native 

salmonids was low, and that colonization was an unlikely event (Amos and Appleby 1999). 

NMFS Biological Status Reviews of West Coast Pacific Salmon 

Stocks 

Since 1991 NMFS has published 15 biological status reviews as part of its obligation 

under ESA. These reviews are individual scientific compilations of the current status of all 

anadromous salmonid populations on the West Coast of the United States, excluding Alaska. 

These are generally regarded as the most complete scientific reviews of Pacific salmon 

abundance ever published. They form the basis for NMFS actions concerning ESA listing 

determinations, as well as the scientific basis for NMFS testimony for litigation and courtroom 

challenges to proposed and implemented listings under ESA. 

In these reviews, teams of experienced Pacific salmon scientists, known as the NMFS 

BRTs for ESA Status Reviews, have identified many factors that have adverse effects on 

salmonids of the West Coast (Weitkamp et al. 1995, Busby et al. 1996, Hard et al. 1996, 

Gustafson et al. 1997, Johnson et al. 1997, 1999, Myers et al. 1998a). The potential biological 

impacts of artificially propagated Pacific salmon have consistently been identified as one of 

several primary factors impacting wild salmonids (Hard et al. 1992, Waples 1991). However, 

Atlantic salmon farms have not been identified as causing adverse effects on Pacific salmon in 

any of the status reviews conducted to date, which cover 55 separate ESUs for Pacific salmon 

species, nor have Atlantic salmon been suggested as a factor for decline of Puget Sound chinook 

salmon or Hood Canal summer-run chum salmon (NMFS 1996, 1998). 
51

POTENTIAL IMPACTS OF SALMON FARMS IN PUGET 

SOUND ON ESSENTIAL FISH HABITAT 

In addition to concerns about adverse impacts to native salmonids resulting from escapes 

of Atlantic salmon, conjecture has been raised that organic input to the EFH and over-water 

structures associated with salmon farming will have a significant negative effect on nearshore 

estuarine and marine habitats used by juvenile salmon in the Puget Sound chinook salmon ESU 

(Eglick 1990, McMather 1990). (There are no commercial salmon farms in the Hood Canal 

summer-run chum salmon ESU.) Apprehension about potential water column impacts, such as 

reduced dissolved oxygen (DO) levels and the stimulation of phytoplankton blooms, are most 

commonly expressed, as well as concerns about accumulation of organic and inorganic material 

and chemotherapeutants in the sediments under and in the vicinity of the salmon farms. These 

issues have been extensively evaluated over the last 15 years in Puget Sound and elsewhere. 

Therefore, only a brief review of the pertinent findings will be presented here. 

Water Column Impacts 

Dissolved nitrogen added to the water column by salmon farms is essentially not 

measurable more than 9 m away from the perimeter of the farm. Correspondingly, there was no 

measurable effect on phytoplankton production near salmon farms, even in countries with 

substantial development of salmon farms (Pease 1977, Weston 1986, Rensel 1988, Parametrix 

1990). Salmon farms in Puget Sound had little to no effect on levels of DO in the water column 

immediately adjacent to the farms (Weston 1986, Brooks 1995). 

Clam Bay, Washington, location of the NMFS Manchester Research Station since 1969, 

and also the location of one of the largest salmon farms in the world since 1972, may be used as 

an example of the type of effects on EFH water quality that can be expected from a well-sited, 

large fish farm. In 1979 the U.S. Environmental Protection Agency (EPA) Region X Water 

Quality Laboratory was constructed on the shore of Clam Bay next to the NMFS Manchester 

Research Station. During most of the 1980s, this laboratory used oyster larvae bioassays to 

determine the level of pollution in water samples taken from other areas in the Pacific Northwest. 

The EPA laboratory used water pumped from Clam Bay as the clean, control baseline water 

against which oyster larvae survival in polluted water was compared. The laboratory drew the 

control water less than 200 m from the salmon farm. If the salmon farm had adversely effected 

the ambient water quality, the EPA investigations would have been severely compromised. 

However, there are no reports that they were compromised. During the same period, a study 

investigating the best places in Puget Sound for mussel culture found that Clam Bay was a poor 

site for mussel culture as the waters there were “clear, deep blue,” and that “large blooms of 

phytoplankton to support fast growth are rarely found” (Skidmore and Chew 1985). The NMFS 

Manchester Research Station was involved in a plethora of important scientific studies with 

salmon during this period, all of which required the use of high quality seawater. Concurrent 

with the EPA and NMFS work and the mussel study, the commercial salmon farm in Clam Bay 

reared about 3 million fish per year. Claims that salmon farms will adversely affect EFH by 

polluting the water or stimulating blooms of phytoplankton have not been verified by numerous 
52

scientific investigations conducted in Clam Bay during a period of intense salmon farming. It 

should be noted that the salmon farm site in Clam Bay does not meet current Washington State 

siting criteria, which require specific depths and tidal flows for salmon farm location (WDOE 

1986). Because the salmon farm was in existence before siting criteria were developed, it was 

allowed to remain at its present site. However, the Clam Bay situation can be used to 

demonstrate that the salmon farm siting criteria used in Puget Sound since 1986 adequately 

protects the environment occupied by ESA-listed chinook and summer-run chum salmon.

Comparison to Benthic Impacts of Other Activities in the Pacific 

Northwest 

Sewage Treatment Plants 

Since the area beneath salmon farms is organically enriched by uneaten fish food and by 

fish feces, salmon farms have often been likened to sewage treatment plants (McMather 1990, 

Ellis 1996). However, this simile is not accurate, at least for salmon farms in Puget Sound, for 

several reasons. First, the organically enriched area beneath a salmon farm (Weston 1986, 

Mahnken 1993, Brooks 2000) is far less extensive than the area impacted by a sewage treatment 

plant (Brown et al. 1987, Taylor et al. 1998). Second, waste from a salmon farm does not 

contain the metals and industrial hydrocarbons associated with sewage wastes. Third, the time 

required for biological remediation at a fish farm site ranges from about five months to several 

years (Mahnken 1993, Brooks 2000), whereas the period for full remediation at a sewage outfall 

can easily be at least 10 years (Rosenberg 1976, Pearson and Rosenberg 1978, Shillabeer and 

Tapp 1989). And finally, demersal fish bearing tumors and lesions have not been observed 

nearby or associated with salmon farms in Puget Sound, unlike the situation near sewage 

treatment plants and other contaminated areas of Puget Sound, where diseased and cancerous 

fish are commonly observed (Myers et al. 1998b). 

Fish Processing Plants 

It has been estimated that salmon farms in Puget Sound produce about 0.7 kg of solid 

waste for each kg of fish produced (Weston 1986). At current levels of production, about 7300 t 

(P. Granger2

), all Puget Sound salmon farms produce a cumulative total of about 5000 t of solid 

organic waste per year. By comparison, seafood processing plants discharge substantially more 

organic material onto the benthos. For example, individual seafood processing plants at 

numerous locations, mostly in Alaska, discharge 20,000 to 30,000 t of organic material per year 

into nearshore waters (NMFS 2001a). The waste pile at one plant was estimated to be 200 m in 

diameter and 7 m deep, and at another location, the waste pile covered 4.5 ha to a depth of 1 m 

(NMFS 2001a). The negative effects on the environment from large waste piles such as these 

would certainly be enormous compared to impacts associated with the relatively small amount of 

solid waste produced by Puget Sound salmon farms. However, NMFS (2001a) found that the 

discharges from seafood processing plants in Alaska “appear to be localized and would not be 

expected to adversely affect threatened or endangered species under NMFS jurisdiction.” 
53

Similarly, the markedly smaller organic discharges from Puget Sound salmon farms do not seem 

likely to adversely affect threatened salmonids in Puget Sound. 
54
55

SCALE AND IMPACTS OF SIMILAR ACTIVITIES IN 

PUGET SOUND 

Scale of Salmon Farms and Other Aquaculture 

Salmon Farms 

In 1986 there were 9 sites in Puget Sound where coho salmon or Atlantic salmon were 

raised commercially in net-pen facilities (Weston 1986). In addition, at that time there were 5 

major and 8 minor noncommercial net-pen facilities used by WDFW, tribes, or sportsmen’s 

clubs for delayed release of coho and chinook salmon. By 1990 there were 13 commercial sites, 

each limited to a total surface area of less than 0.8 ha (WDF 1990a). WRAC (1999) reported 6 

companies with leases to sites in Washington in 1997. These included Domsea Farms Inc. (5 

sites), Global Aqua USA Inc. (3 sites), Moore-Clark Co. (USA) Inc. (3 sites and a hatchery), 

Scan Am Farms (3 sites), Sea Farm Washington (3 sites), and British Petroleum (1 site). 

In the last five years, there has been considerable restructuring in the salmon aquaculture 

industry worldwide, with some companies consolidating their position through merger or 

purchase of smaller companies. Consequently, much of the global industry is now dominated by 

a few international companies, although individual farms may still operate under the name of the 

registered leaseholder. In Washington 4 different companies now hold the leases to 12 licensed 

net-pen production sites, of which 9 licensed sites are in production. These are: 

• Cypress Island Inc., which has 3 leases by Cypress Island outside Anacortes and 1 lease in 

Skagit Bay, and under Northwest Farms, 3 leases in Rich Passage, 1 in Port Angeles Harbor 

(formed by combining 2 previous leases), and 1 by Hartstene Island currently not in use. 

• Sunpoint Systems, which has 1 lease in Rich Passage. 

• Jamestown S’Klallum Tribe, which has 1 lease in Discovery Bay, but not in use. 

• Ocean Spar Technologies, a sea-cage manufacturing company, which has 1 lease by Whiskey 

Creek near Port Angeles for research and development trials, but not in use. 

In the State of Washington, statistics provided by the Washington State Department of 

Natural Resources (WDNR 2001) indicate there are 67.5 ha currently leased by companies for 

commercial salmon net-pens, a further 15.7 ha currently leased by the State, tribes, and private 

enterprises for net-pens used for the delayed release of native salmon, and 0.2 ha for herring netpens. All these sites have a different limit for the water surface area leased (for anchorage and 

navigational protection) and the internal surface area for the net-pens in production. The 9 

commercial sites currently operational in Puget Sound have a total of 53 ha under lease from the 

State (ranging from 0.8 to 9.7 ha in size), with a total of 8.7 ha permitted for internal pen 

structures for all Puget Sound salmon farms combined (range 1,951 m2

 to 15,793 m2) (K. 

Bright1). 
56

Oyster Farms 

By comparison, other activities in Washington, such as other types of aquaculture and 

marinas, use habitats similar to those used by salmon farms in Puget Sound, but require 

substantially more space. For example, 585 ha of State-owned aquatic lands are leased for oyster 

farming, primarily in Willapa Bay (WDNR 2001). 

Scale and Impacts of Marinas in Puget Sound 

Scale of Marina Development 

The surface area of Puget Sound covered by salmon farms is insignificant compared to 

the surface area covered by marinas. The total surface area actually covered by floating 

structures for all salmon farms in Puget Sound combined, about 8.7 ha of State-owned aquatic 

lands (WDNR 2001), is much less than the total surface area occupied by several of the larger 

marinas located on State-owned aquatic lands. All the above-water structures at salmon farms in 

Puget Sound would fit several times over inside each of several large Seattle-area marinas such 

as the Elliott Bay Marina, Shilshole Bay Marina, or Fisherman’s Terminal (Port of Seattle 2001, 

Serdar and Cubbage 1996). The Shilshole Bay Marina alone covers 32.1 ha between the 

shoreline and breakwater, with about 3 ha of this area covered by over-water structures such as 

floats and vessels (T. Wheeler13). In addition, marinas are much more numerous than salmon 

farms in Puget Sound. Goodwin and Farrel (1991) published a directory of marinas and moorage 

facilities in the State and listed 379 facilities, about 150 of which were located in the marine 

waters of Puget Sound. Kitsap County, where most of the salmon farms in Puget Sound are 

located, had 26 facilities and more than 2,900 wet moorage slips. The 20 facilities in Kitsap 

County that completed the survey data offered a total of more than 6.4 km of float space to moor 

commercial and recreational boats. Because most marinas are adjacent to the shore and required 

some dredging to accommodate vessels, marinas have probably eliminated some areas which 

previously had been important nearshore habitat for juvenile chinook and summer-run chum 

salmon in Puget Sound, primarily eel grass beds (Healey 1991). By contrast, sites permitted for 

salmon farms are restricted to deeper waters to minimize impacts on benthic communities 

(WDOE 1986). Many marinas are protected by breakwaters which may inhibit free flow of 

water and may impede passage of nearshore migrating juvenile chinook and summer-run chum 

salmon, whereas free-flowing water is essential at a salmon farm. 

Environmental Impacts of Marinas 

Based upon past studies of marinas for WDF, Cardwell et al. (1980) considered reduced 

DO and increased water temperature the greatest potential threat to aquatic organisms in Puget 

Sound marinas. Potential threats such as fecal coliform bacterial contamination of shellfish, the 

leaching of antifouling paints, and the introduction of hydrocarbons via the exhausts of outboard 

motors were also identified (PSWQAT 2001, Cardwell et al. 1980). Subsequently, Cardwell and 

Koons (1981) documented several water quality perturbations within marinas and moorage 

 

13 T. Wheeler, Port of Seattle, P.O. Box 1209, Seattle, WA 98111. Pers. commun., November 6, 2001. 
57

facilities in Puget Sound. Pollutant inputs included runoff from parking lots and storm drains, 

hydrocarbons from outboard motor exhaust, heavy metals from antifouling paints, and biocides 

such as creosote and pentachlorophenol in wood piling and docks. Indirect effects resulted from 

nocturnal reductions in DO due to respiration from blooms of phytoplankton and diurnal 

elevations in water temperature due to solar radiation. By contrast, salmon farms sited under 

current WDOE guidelines only slightly reduce DO, do not increase water temperature (Brooks 

2000), and cold-blooded animals such as salmon do not produce fecal coliform bacteria 

(Geldreich and Clarke 1966). Although some salmon farms in Puget Sound use tarred nets 

similar to those used by commercial salmon fishermen, use of chemical antifoulants is restricted 

to the same compounds used on the hulls of the commercial and recreational salmon fleets. 

Most, if not all salmon farms in Puget Sound are constructed of either plastic or metal, while 

concrete and wood, sometimes treated, is the material of choice in most marinas. Since floating 

wooden structures associated with marinas cover much more surface acreage than salmon farms 

in Puget Sound, marinas would therefore constitute the primary source of wood preservation 

chemicals entering the marine environments of Puget Sound from floating structures. 

An examination of sediments in and near a marina in Port Townsend, Washington, found 

that concentrations of copper, lead, zinc, butylated tins, polyaromatic hydrocarbons, and total 

organic carbon were elevated compared to sediments outside the marina. The zone of influence 

from the marina was observed to extend for a distance of about 150 m from the entrance 

(Crecelius et al. 1990), a somewhat greater distance than the zone of impact typically observed at 

Puget Sound fish farms (Capone et al. 1994). 

In a similar study, also conducted in Port Townsend, concentration of metals in sediments 

under an Atlantic salmon farm were similar to those found at a control site at Point Wilson in the 

Strait of Juan de Fuca. However, for selenium, beryllium, silver, arsenic, lead, copper, and zinc, 

the concentrations of metals under the salmon pens were less than those found near a local 

marina (same marina as above) in Port Townsend (Johnson 1988). Another study in Puget 

Sound found that several marinas violated Washington State water temperature and oxygen 

concentrations standards, primarily due to poor flushing (Cardwell et al. 1980). Unlike marinas, 

which may introduce elevated levels of toxic chemicals to the environment, the primary impact 

from salmon farms consists of organic enrichment and, in some cases, short-term inputs of 

antibiotic residues, which also may occur at public fish-culture facilities. Since marinas occupy 

at least 100 times the total nearshore acreage of salmon farms in Puget Sound, they clearly are a 

greater source of pollutants introduced to EFH. However, although marinas are a significantly 

greater source of toxic chemicals than Atlantic salmon farms in Puget Sound, Crecelius et al. 

(1990) concluded that if the toxic input from all marinas in Puget Sound were similar to the 

marina in Port Townsend mentioned above, the total environmental impact would be very small: 

the annual influx of metals and other contaminants from marinas would be less than a 1% 

addition to the total input to the main Puget Sound Basin from other sources. Since the total 

inputs of chemical pollution to Puget Sound from salmon farms are much less than inputs from 

marinas, it is unlikely that the environmental impacts of salmon farms are equal to or greater 

than the small overall impacts noted for marinas. 
58
59

ESSENTIAL FISH HABITAT AND THE MAGNUSONSTEVENS ACT 

The potential impacts of public and private fish and shellfish on EFH have been 

addressed in Section 3.2.3, Appendix A, of the Essential Fish Habitat Provision of the amended 

Magnuson-Stevens Fishery Conservation and Management Act (Public Law 94-265). It is the 

responsibility of NMFS and the eight regional Fishery Management Councils, under authority of 

the Secretary of Commerce, to: describe and identify EFH in each fishery management plan, 

minimize to the extent practicable the adverse effects of fishing on EFH, and identify other 

potentially deleterious actions to encourage the conservation and enhancement of EFH. The 

potential adverse impacts to EFH on the West Coast can be found on the Pacific States Marine 

Fisheries Commission’s Web site at: www.psmfc.org/efh.html. 

Primary recommendations in Section 3.2.3, Appendix A, to minimize adverse fish culture 

impacts include following established guidelines and policies regarding disease prevention and 

the use of chemotherapeutics, and the use of stocks in hatcheries and salmon farms that will have 

little or no impact on native salmon. The farming of Atlantic salmon in Puget Sound currently 

adheres to the EFH guidelines. 
60
61

REGULATORY STRUCTURE FOR COMMERCIAL 

AQUACULTURE ENTERPRISES IN WASHINGTON AND 

PUGET SOUND 

Most of the extensive body of scientific information pertaining to salmon farming 

published in the last several decades has already been integrated into the regulatory processes of 

Washington State. This information has been incorporated into State regulations relating to farm 

fish escapes, antibiotic residues in sediments, accumulation of organic wastes on the seabed, 

importation of non-native and non-local species, and disease management. These and other 

important regulations and documents pertaining to private salmon farming include: 

• Final programmatic Environmental Impact Statement for fish culture in floating net-pens 

(WDF 1990b) 

• Recommended interim guidelines for the management of salmon net-pen culture in Puget 

Sound (WDOE 1986) 

• Environmental effects of floating mariculture in Puget Sound (Weston 1986) 

• Environment fate and effects of aquacultural antibacterials in Puget Sound (Weston et al. 

1994) 

• Disease control policies of Washington (NWIFC/WDF 1991) 

• Disease control policies of the United States (USFWS 1984) 

• Fish health manual of the WDFW (1996) 

• Marine finfish aquaculture escape prevention reporting and recapture plan (WAC 220-76-

100 to WAC 220-76-160) 

The policies and regulations (and their enforcement) for aquaculture introductions in 

Washington State and British Columbia were reviewed and summarized in detail by Elston 

(1997) in a study of pathways and management of marine nonindigenous species into the shared 

waters of British Columbia and Washington. Shellfish and finfish aquaculture had been 

identified as one of six potential pathways for nonindigenous species introductions for the study, 

and in his final report to the Puget Sound Water Quality Authority, the EPA, and the DFO 

Canada, he stated that the adequacy of information available to assess the relative risks of 

introductions through aquaculture was good, because for more than a decade, Washington State 

and British Columbia have had in place state/provincial and federal procedures specific to 

aquaculture. He noted that intentional introduction of fish and shellfish species was now far 

more restricted than in the past, and that technology could assist further in reducing the risk from 

exotic species introductions by, for example, culturing only strains of sterile organisms. Elston 

(1997) concluded that the risk of introductions from aquaculture was well-defined, the industry 

was highly regulated, and active processes were underway for continuous review of aquaculture 

activities as they involved nonindigenous species. 
62

Agencies Regulating Salmon Farming in Washington 

State of Washington Agencies 

Traditionally, the policy of the State of Washington has been supportive of aquaculture. 

The State was one of the first to recognize that aquaculture was a form of agriculture and enacted 

legislation in 1985 that designated the Washington State Department of Agriculture (WSDA) as 

the lead agency, with WDF (now WDFW) responsible for regulations pertaining to disease 

control and prevention. Recently, Second Substitute House Bill 1499 gives WDFW the authority 

to require all fish farms in Washington to prevent, report, and recapture escaped fish. The 

current policy of the State fosters the commercial and recreational use of the aquatic environment 

for production of food, fiber, income, and public enjoyment from State-owned aquatic lands, and 

identifies aquaculture among legitimate uses. In its policy implementation manual for the use of 

the State’s aquatic resources (WDNR 2000), shellfish and finfish aquaculture is specifically 

designated as an aquatic land use of State-wide value. The WDNR generally encourages this use 

and it takes precedence over other water-dependent uses that have only local interest values. 

While commenting on the possible environmental impact on aquaculture by surrounding 

activities and vice versa in a discussion on net-pens and floating rafts, the manual states again 

that aquaculture remains a favored use of State-owned aquatic lands. WDNR (1999) recently 

published a technical report on the potential for offshore finfish aquaculture in the State. 

Amos and Appleby (1999) summarized the roles and responsibilities of the regulatory 

authorities in the State of Washington with regard to the management of salmon farming in State 

waters, and particularly Atlantic salmon farming. Their summary forms the basis of the 

following overview of the regulatory structure for commercial farms producing either Pacific or 

Atlantic salmon. 

Washington Department of Fish and Wildlife 

WDFW has management and regulatory authority over all free-ranging fish in the State. 

The authority of WDFW over commercial fish culture in State waters is restricted to disease 

control, prevention of escapes, and protection of wildlife in general. Within this authority: 

• The Fin Fish Import and Transfer Permit (WAC 220-77-030) assures that diseases, pests, and 

predators are not introduced or transferred. In addition, under a legal settlement, WDFW is 

required to kill and conduct biological examination of any Atlantic salmon encountered by 

agency staff. 

• Regulation of Marine Fin Fish Aquaculture (WAC 220-76-110 to WAC 220-76-160) gives 

WDFW authority over fish that have escaped from a salmon farm. 

• Hydraulic Project Approval (RCW 75.20.100, WAC 220-120), or HPA, assures that all 

construction projects ensure protection of wildlife and habitats. However, the authority of 

WDFW to require HPAs of aquaculture workers at their sites is not clear. 
63

Washington State Department of Ecology 

WDFW, in association with WDOE and WDNR, provides guidance to State and local 

agencies siting farms to avoid adverse impacts on the environment. In association with WSDA, 

it develops disease control regulations with regard to human health and safety. 

WDOE has regulatory authority over discharges of pollutants into State waters for the 

protection, preservation, and enhancement of the environment. Within this authority: 

• The National Pollution Discharge Elimination System Permit (40 CFR 122.21), or NPDES, 

assures compliance with state and federal water quality laws. 

• The Water Discharge Permit (RCW 90.48) assures that discharges and wastes do not 

adversely affect water quality and standards. 

Under the Clean Water Act and the Water Pollution Control Act, WDOE can take 

regulatory action against net-pen operators who allow Atlantic salmon to escape. This follows 

the determination by the PCHB that escaped Atlantic salmon are “pollutants,” primarily because 

they escaped from a point source (PCHB 1998), the fish themselves constituted biological 

material, and are a species not native to Puget Sound. The PCHB also adjudicates appeals over 

permits issued by WDOE. In association with WDFW and WDNR, WDOE provides guidance 

to State and local agencies on siting farms to avoid adverse impacts on the environment. 

Washington State Department of Natural Resources 

WDNR has regulatory authority over State-owned aquatic lands, including all bedlands 

of Puget Sound, navigable rivers, lakes, and other waters. The authority also extends over lands 

covered and exposed by the tide, and most shores of navigable lakes and other fresh waters. 

Within this authority, the Aquatic Lands Lease (RCW 79.90-79.96), or ALL, assures that all uses 

of the land and the proposed facilities are as specified. WDNR, in association with WDFW and 

WDOE, provides guidance to State and local agencies on siting farms to avoid adverse impacts 

on the environment. 

Washington State Department of Agriculture 

WSDA is responsible for assuring the safety of the State’s food supply, providing 

protection from diseases and pests, and facilitating movement of agriculture products in domestic 

and international markets. With WDFW it jointly develops disease control regulations with 

regard to human health and safety. 

Local counties in Washington State act as lead agencies for applying the environmental 

policies of the State and the management of their respective county shorelines. Among relevant 

authorities: 

• The State Environmental Policy Act (RCW 43.21C, WAC 197-11), or SEPA, assures 

consideration of social and environmental impacts of proposed actions. 

• The Shoreline Management Act (RCW 90.58), or SMA, assures appropriate and orderly 

development of State shorelines, management of their uses, and preservation of their natural 

character. 
64

Federal Agencies 

A number of federal agencies (NMFS, U.S. Army Corps of Engineers, USFWS, U.S. 

Coast Guard, and EPA), together with respective State agencies (WDFW, WDOE, WDNR, 

WSDA), have management and regulatory authority over the use of all waters by the public. 

NMFS administers the ESA for anadromous salmonids, including authorizing Section 10 

Exception Permits, which assures protection of public interests, including navigation, water 

safety, and water quality. In collaboration with USFWS and WDNR, NMFS permits the use of 

predator control methods (nonlethal) for birds and mammals in accordance with permit 

restrictions. 

The FDA is responsible for the protection of consumers by enforcing the Federal Food, 

Drug, and Cosmetic Act, and several related public health laws. It is also responsible for the 

safety of feed and drugs for pets and farm animals. Salmon and trout farmers are restricted to the 

use and conditions of veterinary medicines, drugs, growth enhancers, and other chemical 

supplements licensed by the FDA. 

The Treaty Tribes of the State of Washington co-manage fisheries resources in the State 

with WDFW and have input into finfish culture regulations in common with WDFW. 

The Regulatory Structure for Public and Tribal Hatcheries in 

Washington 

Public and tribal hatcheries producing Pacific salmon (and other fish) in Washington 

State must conform to the same general directives that regulate commercial hatcheries and farms 

(see WDFW subsection above). These regulations, as described, are concerned with protection 

of the environment or the health and safety of other plants and animals, including human 

consumers. However, since 1994 when a number of Pacific salmonid species in the region were 

listed for protection under the ESA, there have been some differences in regulations for public 

and tribal hatcheries that rear federally listed salmonids. Generally, the production of listed 

salmon populations in public and tribal hatcheries is now restricted to recovery purposes only, 

and not to provide fish for subsequent commercial or recreational harvest. 

As part of this approach, NMFS (2001b) has been working with management agencies in 

the region to develop Hatchery and Genetic Management Plans. The HGMP procedure provides 

a thorough description of each hatchery operation, including the facilities used, methods 

employed to propagate and release fish, and measures of performance. There are also sections 

dealing with the status of listed stocks that may be affected by the plan, anticipated listed-fish 

“take” levels, and a description of measures to minimize risk to listed fish. However, once the 

HGMP is completed, accepted, and followed, hatchery managers are assured that their activities 

are all in compliance with ESA and no further permitting is required. 
65

CONCLUSIONS REGARDING POTENTIAL IMPACTS OF 

ATLANTIC SALMON CULTURE IN PUGET SOUND 

These conclusions regarding the potential impacts of Atlantic salmon culture on the Puget 

Sound chinook salmon and Hood Canal summer-run chum salmon ESUs are based on three 

important assumptions. The first assumption is that the salmon farming industry in Puget Sound 

remains approximately the same size as currently or in the recent past. A significant expansion 

of the industry may increase risks and would require a reconsideration of some of the potential 

impacts discussed in this review. The second assumption is that salmon farms in Puget Sound 

continue to rear only Atlantic salmon. Should the local industry shift production to coho or 

chinook salmon or to steelhead, the risks for hybridization, dilution of the gene pool, 

colonization, and competition for natural resources with wild salmonids will be greater than they 

are now with Atlantic salmon culture. Third, these conclusions assume that Atlantic salmon 

farmers in Washington continue to use only stocks presently in culture and that no new Atlantic 

salmon stocks are brought into the State. 

Based on these assumptions, this review draws the following risk assessment 

conclusions: It finds no risk for one parameter, low risk for several parameters, little risk for 

other parameters, and no parameters for which the potential impacts from Atlantic salmon farms 

in Puget Sound are considered to be serious or even moderate. In particular: 

1. There is little risk that Atlantic salmon which escape from net-pen farms will 

hybridize with Pacific salmon or dilute the native gene pool. Atlantic salmon x Pacific salmon 

hybrids are not observed in nature, whether for introduced Atlantic salmon in western North 

America or for North American salmonids introduced to Europe and the other continents. By 

comparison, successful interspecific and intraspecific hybridization between North American 

salmonids has been regularly recorded. 

2. At present, there is no risk of adverse genetic interaction between transgenic farm fish 

and wild salmon in Puget Sound, as there are no transgenic salmon being commercially cultured 

in Washington and no plans to raise them here in the future. 

3. There is little risk that Atlantic salmon will colonize habitats in the Puget Sound 

chinook salmon and Hood Canal summer-run chum salmon ESUs. Atlantic salmon of various 

sizes occasionally escape into the waters of Puget Sound. Deliberate releases of Atlantic salmon 

have failed to establish local self-sustaining populations anywhere in the Northern Hemisphere 

outside their native range. Monitoring programs in British Columbia find naturally produced 

juveniles from time to time, but naturally produced adults have not been observed. 

4. There is a low risk that the presence of salmon farms will increase the incidences of 

disease among wild fish. The specific diseases and their prevalence in Atlantic salmon stocks 

cultured in net-pens in Puget Sound are no different than those of the more numerous cultured 

stocks of Pacific salmon in hatcheries, which in turn have not been shown to have a high risk for 

infecting wild salmonids. All Pacific and Atlantic salmon stocks currently cultured in 

Washington are inspected annually for bacterial and viral pathogens, and the movement of fish 

from place to place is regulated by permit. 
66

5. There is little risk that existing stocks of Atlantic salmon will be a vector for the 

introduction of an exotic pathogen into Washington State. Movements of fish into and within 

Pacific Northwest states are well-regulated, including the requirement for disease-free 

certification. No Atlantic salmon stocks have been transferred into Washington State since 1991. 

6. There is little risk that the development of antibiotic-resistant bacteria in net-pen 

salmon farms or Atlantic salmon freshwater hatcheries will impact native salmonids. All drugs 

used in Atlantic and Pacific salmon hatcheries are safe and efficacious and approved by the 

FDA. Drug resistant bacteria have been commonly observed in fish culture facilities in 

Washington State for over 40 years and no resulting adverse impacts on wild salmonids have 

been reported. 

7. There is little risk that escaped Atlantic salmon or their progeny will become an 

introduced non-native species that will be a predator of indigenous species. Analyses of the 

stomachs of recovered farm Atlantic salmon and of the few naturally produced juveniles caught 

in the wild have shown that only a few juvenile Pacific salmon have been eaten by Atlantic 

salmon. Other introduced non-native species are credited with consuming hundreds of thousands 

of juvenile salmon in, for example, one reservoir of the Columbia River. These non-native 

predators have been deliberately or accidentally introduced and are now managed for sustained 

natural reproduction to enhance recreational fisheries and contribute to sport fishing revenues. 

8. The risk that escaped Atlantic salmon or their progeny will compete with native 

salmonids for natural forage is low. Few prey items of any sort have been found in the stomach 

contents of escaped Atlantic salmon of any size. The few natural prey items any escaped fish 

might consume is negligible compared with the food requirements of the tens of millions of 

hatchery-reared juvenile Pacific salmon released each year into Puget Sound and its tributaries. 

9. The risk of adverse impact to EFH is low because the salmon farming industry is wellregulated at local, state, and federal levels. Salmon farming impacts on EFH are no more 

harmful than impacts from marinas, which cover much more nearshore acreage in Puget Sound, 

and are less than impacts from Pacific Northwest seafood processing facilities. 
67

CITATIONS 

ADF&G (Alaska Dept. Fish and Game). 1983. Fish culture manual. Alaska Dept. Fish and Game, 

Juneau, AK, 36 p. 

ADF&G (Alaska Dept. Fish and Game). 1999. Alaska expresses concern over Atlantic salmon. 

Imported species poses threat to wild salmon stocks. Press release, March 1. Alaska Dept. Fish 

and Game, Public Communications Section, P.O. Box 25526, Juneau, AK 99802. 

ADF&G (Alaska Dept. Fish and Game). 2002. Atlantic salmon. A white paper. Internet document, 

http://www.state.ak.us/local/akpages/FISH.GAME/geninfo/special/as/docs/AS_white2002.pdf. 

Alverson, D. L., and G. T. Ruggerone. 1997. Escaped farm salmon: environmental and ecological 

concerns. In British Columbia Salmon Aquaculture Review, Environmental Assessment Office, 

Vancouver B.C. Discussion paper, Part B, Vol. 3, August. Internet document, 

http://www.eao.gov.bc.ca. 

Amos, K. H., and A. Appleby. 1999. Atlantic salmon in Washington State: a fish management 

perspective. Washington Dept. Fish and Wildlife, Olympia, WA. Internet document, 

http://www.wa.gov/wdfw/fish/atlantic/toc.htm. 

Bachen, B. 1994. The impacts of success: a case history of Hidden Falls hatchery. In Northeast Pacific Pink 

and Chum Salmon Workshop, Feb. 24-26, 1993, Juneau, AK, p. 46-56. B. Bachen, Univ. Alaska, 

210 Anderson Bldg., 11120 Glacier Hwy., Juneau, AK, 99801. 

Bartley, D. M., G. A. E. Gall, and B. Bentley. 1990. Biochemical detection of natural and artificial 

hybridization of chinook and coho salmon in northern California. Trans. Am. Fish. Soc. 119:431-

437. 

BC.com (British Columbia.com). 2001. Fish of British Columbia—Trout. British Columbia.com. 

Internet document, http://www.britishcolumbia.com/Fishing/fish/trout.html. 

BCSFA (British Columbia Salmon Farmers Association). 1999. Industry facts and figures. Internet 

document, http://www.salmonfarmers.org. 

Beall, E., M. Heland, and C. Marty. 1989. Interspecific relationships between emerging Atlantic salmon, 

Salmo salar, and coho salmon, Oncorhynchus kisutch, juveniles. J. Fish. Biol. 35(A):285-293. 

Beamesderfer, R. C., and A. A. Nigro. 1988. Predation by resident fish on juvenile salmonids in a mainstem 

Columbia reservoir: III. Abundance and distribution of northern squawfish, walleye, and smallmouth 

bass. In B.E. Rieman (ed.), Predation by Resident Fish on Juvenile Salmonids in John Day 

Reservoir, 1983-1986, p. 211-248. Vol. 1, Final Research Rep., U.S. Dept. Energy, Portland, OR. 

Beamesderfer, R. C., D. L. Ward. 1994. Review of the status, biology, and alternatives for management of 

smallmouth bass in John Day Reservoir. Oregon Dept. Fish and Wildlife Info. Rep. 94-4. 

Beamish, R. J., and D. Bouillon. 1993. Pacific salmon production trends in relation to climate. Can. J. Fish. 

Aquat. Sci. 50:1002-1016. 
68

Beamish, R. J., C. Mahnken, and C. M. Neville. 1997. Hatchery and wild production of Pacific salmon in 

relation to large-scale, natural shifts in the productivity of the natural environment. ICES J. Mar. Sci. 

54:1200-1215. 

Beamish, R., D. Noakes, G. McFarlane, W. Pinnix, R. Sweeting, and J. King. 2000. Trends in coho marine 

survival in relation to the regime concept. Fish. Ocean. 9:114-119. 

Behnke, R. 1992. Native trout of western North America. Amer. Fish. Soc., Monograph 6. Bethesda, MD, 

275 p. 

Berg, M. 1977. Pink salmon, Oncorhynchus gorbuscha (Walbaum) in Norway. Rep. Instit. Freshwater 

Res. 56:12-17. 

Bisbal, G. A., and W. E. McConnaha. 1998. Consideration of ocean conditions in the management of 

salmon. Can. J. Fish. Aquat. Sci. 55:2178-2186. 

Black, E. A., D. J. Gillis, D. E. Hay, C. W. Haegele, and C. D. Levings. 1992. Predation by caged salmon in 

British Columbia. Bull. Aquacult. Assoc. Can. 92-5:58-60. 

Blanc, J. M., and B. Chevassus. 1979. Interspecific hybridization of salmonid fish: I. Hatching and 

survival up to the 15th day after hatching in F1 generation hybrids. Aquaculture 18:21-34. 

Blanc, J. M., and B. Chevassus. 1982. Interspecific hybridization of salmonid fish: II. Survival and 

growth up to the 4th month after hatching in F1 generation hybrids. Aquaculture 29:383-387. 

Brackett, J. 1991. Potential disease interactions of wild and farmed fish. Bull. Aquacult. Assoc. Can. 

91-3:79-80. 

Brooks, K. M. 1995. Environmental sampling at Sea Farm Washington Inc., net-pen facility II salmon 

farm, Port Angeles Harbor, 1995. Produced for the Washington Dept. Natural Resources, 

Olympia, WA, 20 p. 

Brooks, K. M. 2000. Database report to the Ministry of Environment describing sediment 

physicochemical response to salmon farming in British Columbia, 1996 through April 2000. BC 

Salmon Farmers Association, 41 p. (Available from BC Salmon Farmers Association,1200 West 

Pender Street, Vancouver, BC, Canada V6E 2S9.) 

Brown, J. R., R. J. Gowen, and D. S. McLusky. 1987. The effect of salmon farming on the benthos of a 

Scottish sea loch. J. Exp. Mar. Biol. Ecol. 109:39-51. 

Brown, T. L. 1975. The 1973 salmonid run: New York’s Salmon River sport fishery, angler activity, and 

economic impact. New York Sea Grant Program, Univ. New York, Stony Brook. Publ. NYSSGPRS-75-024, 29 p. 

Buckley, R. M. 1999. Incidence of cannibalism and intra-genetic predation by chinook salmon 

(Oncorhynchus tshawytscha) in Puget Sound, Washington. Washington Dept. Fish and Wildlife, 

Resource Assessment Division Rep., RAD 99-04, 22 p. 

Busack, C. A., and K. P. Currens. 1995. Genetic risks and hazards in hatchery operations: fundamental 

concepts and issues. In Schramm, H. L., and R. G. Piper (eds.), Uses and Effects of Cultured 

Fishes in Aquatic Ecosystems, p. 71-80. Amer. Fish. Soc. Symp. 15. Bethesda, MD. 
69

Busack, C., and A. R. Marshall. 1995. Defining genetic diversity units in Washington salmonids. 

Washington Dept. Fish and Wildlife, Tech. Rep., RAD 95-02, 19 p. 

Busby, P. J., T. C. Wainwright, G. J. Bryant, L. J. Lierheimer, R. S. Waples, F. W. Waknitz, and I. V. 

Lagomarsino. 1996. Status review of West Coast steelhead from Washington, Idaho, Oregon, and 

California. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-27, 261 p. 

Campton, D. E., and J. M. Johnston. 1985. Electrophoretic evidence for a genetic admixture of native 

and nonnative rainbow trout in the Yakima River, Washington. Trans. Am. Fish. Soc. 114:782-

793. 

Capone, D. G., D. P. Weston, V. Miller, and C. Shoemaker. 1994. Antibacterial residues in marine 

sediments and invertebrates following chemotherapy in aquaculture. Aquaculture 145:55-75. 

Cardwell, R. D., M. I. Carr, and E. W. Sanborn. 1980. Water quality and flushing of five Puget Sound 

marinas. Tech. Rep. 56, Washington Dept. Fisheries, Olympia, WA, 77 p. 

Cardwell, R. D., and R. R. Koons. 1981. Biological considerations for the siting and design of marinas 

and affiliated structures in Puget Sound. Tech. Rep. 60, Washington Dept. Fisheries, Olympia, 

31 p. 

Carl, G. C., W. A. Clemens, and C. C. Lindsey. 1959. The freshwater fishes of British Columbia. British 

Columbia Province Museum Handbook 5, Vancouver, BC, Canada, 192 p. 

Carrel, C. 1998. Killer salmon. Seattle Weekly, Sept. 17-23. 

CFR (Code of Federal Regulations). 2001. Title 50 Regulations. Internet document 

http://www.access.gpo.gov/su_docs. 

Chevassus, B. 1979. Hybridization in salmonids: results and perspectives. Aquaculture 17:113-128. 

Chilcote, M. W. 1997. Conservation status of steelhead in Oregon. Report to ESA Administrative Record 

for lower Columbia River coho salmon, Oregon Dept. Fish and Wildlife, Portland, OR, August 1997. 

(Available from Environmental and Technical Services Division, NMFS, 525 Oregon Street, 

Portland, OR 97232.) 

City of Bellevue. 2002. Shorezone development literature review–structures and predators. City of Bellevue 

web site, www.ci.bellevue.wa.us/. 

Coleman, P., and T. Rasch. 1981. A detailed listing of the liberations of salmon into the open waters of the 

State of Washington during 1980. Washington Dept. Fisheries, Progress Rep. 132, 360 p. 

Cooney, R. T., R. D. Brodeur. 1998. Carrying capacity and North Pacific salmon production: stockenhancement implications. Bull. Mar, Sci, 62:443-464. 

Crawford, S. S. 2001. Salmonine introductions into the Great Lakes: an historical review and evaluation 

of ecological effects. Can. Spec. Pub. Fish. Aquat. Sci. 132, 205 p. 

Crecelius, E., T. Fortman, S. Kesser, C. Apts, and O. Cotter. 1990. Contaminant loading to Puget Sound 

from two marinas. Puget Sound Notes, winter, 1990:3-9. 
70

Daily, K., T. Shrader, R. Temple, and B. Hooton. 1999. Introduced fishes management strategies. 

Oregon Dept. Fish and Wildlife. Internet document, 

http://www.dfw.state.or.us/ODFWhtml/publicreview.pdf. 

Dill, W. A., and A. J. Cordone. 1997. History and status of introduced fishes in California, 1871-1996. 

Calif. Dep. Fish Game Fish. Bull. 178, 411 p. 

Dobbyn, P. 2001. Fish Farming spurs concerns. Anchorage Daily News, August 1. 

Dymond, J. R. 1932. The trout and other game fishes of British Columbia. Biological Board of Canada, 

Ottawa, ON, Canada, 51 p. 

EAO (Environmental Assessment Office, BC, Canada). 1997. British Columbia salmon aquaculture 

review. Environmental Assessment Office, Government of British Columbia, 836 Yates Street, 

Victoria, BC, Canada V8V 1X4. 

Einum, S., and I. A. Fleming. 1997. Genetic divergence and interactions in the wild among native, 

farmed and hybrid Atlantic salmon. J. Fish Biol. 50:634-651. 

Eglick, P. J. 1990. Response to comments. Final programmatic environmental impact statement. Fish 

culture in floating net-pens. Prepared by Parametrix Inc., for Washington State Dept. Fisheries, 

115 General Administration Building, Olympia, WA 98504, 161 p. 

Ellis, D. 1996. Net loss. The salmon netcage industry in British Columbia. Report to the David Suzuki 

Foundation, Suite 219, 2211 West Fourth Avenue, Vancouver, BC, Canada V6K 4S2, 196 p. 

Elston, R. 1997. Pathways and management of marine nonindigenous species in the shared waters of 

British Columbia and Washington. Final Report to the Puget Sound Water Quality Authority, 

U.S. Environmental Protection Agency, and the Dept. Fisheries and Oceans Canada. Internet 

document, http://www.wa.gov/puget_sound/shared/nis.html. 

Emery, L. 1985. Review of fish species introduced in the Great Lakes, 1819-1974. Great Lakes Fisheries 

Commission Tech. Rep. 45, 16 p. 

Flagg, T. A., F. W. Waknitz, D. J. Maynard, G. B. Milner, and C. V. W. Mahnken. 1995. The effect of 

hatcheries on native coho salmon populations in the Lower Columbia River. Amer. Fish. Soc. 

Symp. 15:366-375. 

Foerster, R. E. 1935. Interspecific cross-breeding of Pacific salmon. Trans. Royal Soc. Can. Series 3, 

29, Section 5:21-33. 

Foott, J. S., and R. L. Walker. 1992. Disease survey of Trinity River salmonid smolt populations. 

Report by the U.S. Fish and Wildlife Service to the California-Nevada Fish Health Center, 

Anderson, CA, 96007, 40 p. 

FPC (Fish Passage Center). 1999. Current and historic mark release information, 1985-present. Fish 

Passage Center, Portland, OR. Internet document, http://www.fpc.org/Hatchery/MarkRel.htm. 

Fresh, K. L. 1997. The role of competition and predation in the decline of Pacific salmon and steelhead. In

D. J. Stouder, P. A. Bisson, R. J. Naiman (eds.), Pacific Salmon and Their Ecosystems, p. 245-276. 

Chapman & Hall, New York, NY. 
71

Freymond, B., and S. Foley. 1985. Wild steelhead: spawning escapement estimates for Boldt Case area 

rivers. Washington Dept. Game, Project AFS 127-1, 204 p. 

Galbreath, P. F., and G. H. Thorgaard. 1995. Sexual maturation and fertility of diploid and triploid 

Atlantic salmon x brown trout hybrids. Aquaculture 137:299-311. 

Geldreich, E. E., and N. A. Clarke. 1966. Bacterial pollution indicators in the intestinal tract of freshwater 

fish. Appl. Micro. 14:429-437. 

Gibson, R. J. 1981. Behavioral interactions between coho salmon, Atlantic salmon, brook trout and 

steelhead trout at the juvenile fluvial stages. Can. Tech. Rep. Fish. Aquat. Sci. 1029. 

Gilbertsen, N. 1997. Letter to U.S. Senator Ted Stevens, Alaska, April 25. 

Glavin, T. 2001. West Coast salmon farms: no news is bad news. EnCompass magazine, July/August. 

Goodwin, R. F., and T. J. Farrell. 1991. Washington state marina directory. Univ. Washington Sea 

Grant Program, Seattle, WA, Publ. WASHU-D-91-002. 

Gray A. K., M. A. Evans, and G. H. Thorgaard. 1993. Viability and development of diploid and triploid 

salmonid hybrids. Aquaculture 122:125-142. 

Gresswell, R. E., (ed.). 1988. Status and management of interior stocks of cutthroat trout. Amer. Fish. Soc. 

Symp. 4, Bethesda, MD. 

Griffiths, R. H. 1983. Stocking practices and disease control. In F.P. Meyer and J.W. Warren (eds.), A 

Guide to Integrated Fish Health Management in the Great Lakes Basin, p. 87-88. Great Lakes 

Fisheries Commission Special Publ. 83-2. 

Gross, M. 1998. One species with two biologies: Atlantic salmon (Salmo salar) in the wild and in 

aquaculture. Can. J. Fish. Aquat. Sci. 55(Suppl. 1):131-144. 

Group Participants. 2001. Summary of discussions regarding the ecological interactions between farmed and 

wild salmon. In P. Gallauger and C. Orr (eds.), Proceedings of the Symposium on Aquaculture and 

the Protection of Wild Salmon, March 6, 2000, Simon Fraser University, Vancouver, BC, p. 33-37. 

(Available from Simon Fraser Univ., 8888 University Pl., Burnaby, BC, Canada V5A IS6.) 

Gustafson, R. G., T. C. Wainwright, R. G. Kope, K. Neely, F. W. Waknitz, L. T. Parker, and R. S. Waples. 

1997. Status review of sockeye salmon in Washington and Oregon. U.S. Dept. Commer., NOAA 

Tech. Memo. NMFS-NWFSC-33, 282 p. 

Hard, J. J., R. P. Jones, Jr., M. R. Delarm, and R. S. Waples. 1992. Pacific salmon and artificial propagation 

under the Endangered Species Act. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-2, 

56 p. 

Hard, J. J., R. G. Kope, W. S. Grant, F. W. Waknitz, L. T. Parker, and R. S. Waples. 1996. Status review of 

pink salmon from Washington, Oregon, and California. U.S. Dept. Commer., NOAA Tech. Memo. 

NMFS-NWFSC-25, 131 p. 
72

Harrell, L. W., R. A. Elston, T. M. Scott, and M. T. Wilkinson. 1986. A significant new systemic disease 

of net-pen reared chinook salmon (Oncorhynchus tshawytscha) brood stock. Aquaculture 

55:249-262. 

Harrell, L. W., T. A. Flagg, T. M. Scott, and F. W. Waknitz. 1985. Snake River fall chinook salmon 

brood-stock program. Annual Report, 1984. Coastal Zone and Estuarine Studies Division, 

NWAFC, NMFS, Seattle, WA. 

Harrell, L. W., C. V. W. Mahnken, T. A. Flagg, E. F. Prentice, F. W. Waknitz, J. L. Mighell, and A. J. 

Novotny. 1984. Status of the NMFS/USFWS Atlantic salmon brood-stock program. Coastal 

Zone and Estuarine Studies Division, Tech. Memo. 6-84, NWAFC, NMFS, Seattle, WA, 27 p. 

Hart, J. L. 1973. Pacific Fishes of Canada. Fish. Res. Board Can. Bull. 180, 740 p. 

Healey M. C. 1991. Life history of chinook salmon (Oncorhynchus tshawytscha). In C. Groot and L. 

Margolis (eds.), Pacific Salmon Life Histories, p. 311-393. UBC Press, Vancouver, BC, Canada. 

Heard, W. R. 1998. Do hatchery salmon affect the North Pacific Ocean ecosystem? N. Pac. Anad. Fish. 

Comm. Bull. 1:405-411. 

Hearn, W. E., and B. E. Kynard. 1986. Habitat utilization and behavioral interaction of juvenile Atlantic 

salmon (Salmo salar) and rainbow trout (S. gairdneri) in tributaries of the White River of Vermont. 

Can. J. Fish. Aquat. Sci. 43:1988-1998. 

Heggberget, T. G., F. Oekland, and O. Ugedal. 1993. Distribution and migratory behavior of wild and 

farmed Atlantic salmon (Salmo salar) during return migration. Aquaculture 118:73-83. 

Hindar, K., A. Ferguson, A. Youngson, and R. Poole. 1998. Hybridization between escaped farmed 

Atlantic salmon and brown trout: frequency, distribution, behavioral mechanisms, and effects on 

fitness. In K.G. Barthel, H. Barth, M. Bohle-Carbonell, C. Fragakis, E. Lipiatou, P. Martin, G. 

Ollier, and M. Weydent (eds.), Third European Marine Science and Technology Conference. 

Lisbon 23-27 May 1998, p.134-137. Project Synopses Vol. 5, Fisheries and Aquaculture. 

Holland, J. S., and M. McKean. 1992. FRED 1991 annual report to the Alaska State Legislature. Alaska 

Dept. Fish and Game, Juneau, AK, 150 p. 

Howard, C. 1999. Wild Atlantic salmon now reproducing off B.C. coast. Vancouver Sun, September 23. 

Howell, P., K. Jones, D. Scarnecchia, L. LaVoy, W. Kendra, and D. Ortmann. 1985. Stock assessment of 

Columbia River anadromous salmonids: II. Steelhead stock summaries, stock transfer guidelines–

information needs. U.S. Dept. Energy, Bonneville Power Administration, Project No. 83-335, 1032 

p. 

Hunter, J. G. 1949. Occurrence of hybrid salmon in the British Columbia commercial fishery. Fish. Bd. 

Can. Pac. Coast Sta. Prog. Rep. 81:91-92. 

Idyll, C. 1942. Food of rainbow, cutthroat, and brown trout in the Cowichan River system, B.C. J. Fish. 

Res. Board Can. 5:448-458. 

IHOT (Integrated Hatchery Operations Team). 1995-1998. Hatchery Audit Reports. Internet documents, 

www.streamnet.org/ihot_audit/hatchery.html. 
73

Intrafish. 2000. Salmon farming and the environment: of drugs and chemicals. Industry Rep. No. 2/00. 

Internet document, http://www.intrafishservices.com. 

Johnsen, B. O., and A. J. Jensen. 1986. Infestations of Atlantic salmon, Salmo salar, by Gyrodactylus 

salaris in Norwegian rivers. J. Fish Biol. 29:233-241. 

Johnsen, B. O., and A. J. Jensen. 1988. Introduction and establishment of Gyrodactylus salaris

Malmberg, 1957, on Atlantic salmon. Salmo salar L., fry and parr in the river Vefsna, northern 

Norway. J. Fish Dis. 11:35-45. 

Johnson, A. 1988. Port Townsend pen-reared salmon mortality: results of screening surveys for toxic 

chemicals in tissues, sediments, seawater, and effluents, October 1987. Wash. Dept. Ecol. Water 

Quality Invest. Sec., Seg. No. 09-17-01, 33 p. 

Johnson, O. W., W. S. Grant, R. G. Kope, K. Neely, F. W. Waknitz, and R. S. Waples. 1997. Status review 

of chum salmon from Washington, Oregon, and California. U.S. Dept. Commer., NOAA Tech. 

Memo. NMFS-NWFSC-32, 280 p. 

Johnson, O. W., M. H. Ruckelshaus, W. S. Grant, F. W. Waknitz, A. M. Garrett, G. J. Bryant, K. Neely, J. J. 

Hard, and R. S. Waples. 1999. Status review of coastal cutthroat trout from Washington, Oregon, 

and California. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-37, 292 p. 

Jones, M. L., and L. W. Stanfield. 1993. Effects of exotic juveniles salmonines on growth and survival of 

juvenile Atlantic salmon (Salmo salar) in a Lake Ontario tributary. In J. Gibson and R. E. Cutting 

(eds.), Production of Juvenile Atlantic Salmon Salmo Salar in Natural Waters, p. 71-79. Can. Spec. 

Pub. Fish. Aquat. Sci. 118. 

Jordan, W. C., and E. Verspoor. 1993. Incidence of natural hybrids between Atlantic salmon, Salmo 

salar L. and brown trout, Salmo trutta L, in Britain. Aquacult. Fish. Manage. 24:373-377. 

Kent, M. L., and T. T. Poppe. 1998. Diseases of seawater net-pen-reared salmonid fishes. Pacific 

Biological Station, Dept. Fish and Oceans, Nanaimo, BC, Canada, 138 p. 

Kostow, K. 1995. Biennial report on the status of wild fish in Oregon. Oregon Dept. Fish and Wildlife, 

Salem, OR, 217 p. 

Krueger, C. C., and B. May. 1991. Ecological and genetic effects of salmonid introductions in North 

America. Can. J. Fish. Aquat. Sci. 48 (Suppl. 1):66-77. 

Le, P. 1999. Tide currents free 100,000 penned Atlantic salmon. Seattle Post-Intelligencer, June 15. 

Leary, R. F., F. W. Allendorf, and G. K. Sage. 1995. Hybridization and introgression between introduced 

and native fish. Amer. Fish. Soc. Symp. 15:91-101. 

Leider, S., J. Loch, and P. Hulett. 1987. Studies of hatchery and wild steelhead in the Lower Columbia 

Region. Washington Dept. Fish and Wildlife, Fisheries Management Division Progress Rep. 87-8, 

130 p. 

Leitritz, E., and R. C. Lewis. 1980. Trout and salmon culture hatchery methods. Cal. Fish. Bull. 164. 

Univ. California Division of Agriculture and Natural Resources, Oakland, CA, 197 p. 
74

Lever, C. 1996. Naturalized fishes of the world. Academic Press, New York, NY, 408 p. 

Loginova, G. A., and S. V. Krasnoperova. 1982. An attempt at crossbreeding Atlantic salmon and pink 

salmon (preliminary report). Aquaculture 27:329-337. 

MacCrimmon, H. R. 1971. World distribution of the rainbow trout (Salmo gairdneri). J. Fish. Res. 

Board Can. 28:663-704. 

MacCrimmon, H. R., and S. Campbell. 1969. World distribution of the brook trout (Salvelinus 

fontinalis). J. Fish. Res. Board Can. 26:1699-1725. 

MacCrimmon, H. R., and B. L. Gots. 1979. World distribution of Atlantic salmon, Salmo salar. J. Fish. 

Res. Board Can. 36:423-457. 

Mahnken, C. V. W. 1993. Benthic faunal recovery and succession after removal of a marine fish farm. 

Ph.D. Dissertation, Univ. Washington, Seattle, WA, 290 p. 

Mahnken, C. V. W., G. T. Ruggerone, F. W. Waknitz, and T. Flagg. 1998. A historical perspective on 

salmonid production from Pacific rim hatcheries. North Pacific Anadromous Fisheries Commission 

Bulletin 1:38-53. 

Marsh, K. 1999. Atlantic salmon spawn in B.C. Fly Rod & Reel magazine, November/December. 

Marsh, K. 2000. Cowichan River days. Fly Rod & Reel magazine, March/April. 

Marshall, A. 1997. Genetic analysis of Abernathy Creek juvenile chinook, investigation of natural 

reproduction by Rogue River stock hatchery-origin chinook. Washington Dept. Fish and Wildlife, 

Fish Management Division Progress Rep., 8 p. 

Marshall, A. R., C. Smith, R. Brix, W. Dammers, J. Hymer, and L. LaVoy. 1995. Genetic diversity units 

and major ancestral lineages for chinook salmon in Washington. In C. Busack and J. B. Shaklee 

(eds.), Genetic Diversity Units and Major Ancestral Lineages of Salmonid Fishes in Washington, p 

C1-C55. Washington Dept. Fisheries Management Program, Resource Assessment Division Tech. 

Rep., No. RAD 95-02. 

McDaniel, T. R., K. M. Pratt, T. R. Meyers, T. D. Ellison, J. E. Follet, and J. A. Burke. 1994. Alaska 

sockeye salmon culture manual. Special Fisheries Rep. No. 6, Alaska Dept. Fish and Game, 

Juneau, AK, 39 p. 

McGowan, C., and W. S. Davidson. 1992. Unidirectional natural hybridization between brown trout 

(Salmo trutta) and Atlantic salmon (S. salar) in Newfoundland. Can. J. Fish. Aquat. Sci. 

49:1953-1958. 

McKay, S., R. H. Devlin, and M. J. Smith. 1996. Phylogeny of Pacific salmon and trout based on growth 

hormone type-2 and mitochondrial NADH dehydrogenase subunit 3 DNA sequences. Can. J. 

Fish Aquat. Sci. 53:1165-1176. 

McKean, M. 1991. FRED 1990 annual report to the Alaska State Legislature. Alaska Dept. Fish and Game, 

Juneau, AK, 167 p. 
75

McMather, G. 1990. Responses to comments. Final programmatic environmental impact statement. 

Fish culture in floating net-pens. Prepared by Parametrix Inc., for Washington State Dept. 

Fisheries, 115 General Administration Building, Olympia, WA 98504. 

McNair, M. 1995. Alaska salmon enhancement program 1994: annual report. Regional Info. Rep. 5J95-06, 

Alaska Dept. Fish and Game, Juneau, AK, 50 p. 

McNair, M. 1996. Alaska salmon enhancement program 1995: annual report. Regional Info. Rep. 5J9-08, 

Alaska Dept. Fish and Game, Juneau, AK, 51 p. 

McNair, M. 1997. Alaska salmon enhancement program 1996: annual report. Regional Info. Rep. 5J97-09, 

Alaska Dept. Fish and Game, Juneau, AK, 48 p. 

McNair, M. 1998. Alaska salmon enhancement program 1997: annual report. Regional Info. Rep. 5J98-03, 

Alaska Dept. Fish and Game, Juneau, AK, 36 p. 

McNair, M. 1999. Alaska salmon enhancement program 1998: annual report. Regional Info. Rep. 5J99-02, 

Alaska Dept. Fish and Game, Juneau, AK, 35 p. 

McNair, M. 2000. Alaska salmon enhancement program 1999: annual report. Regional Info. Rep. 5J00-02, 

Alaska Dept. Fish and Game, Juneau, AK, 34 p. 

McNair, M. 2001. Alaska salmon enhancement program 2000: annual report. Regional Info. Rep. 5J01-01, 

Alaska Dept. Fish and Game, Juneau, AK, 34 p. 

McNair, M., and J. S. Holland. 1993. FRED 1992 annual report to the Alaska State Legislature. Alaska 

Dept. Fish and Game, Juneau, AK, 102 p. 

McNair, M., and J. S. Holland. 1994. Alaska salmon enhancement program 1994: annual report. Alaska 

Dept. Fish and Game, Juneau, AK, 48 p. 

Meloy, B. 2000. Testimony before the Standing Committee on Fisheries and Oceans of the Canadian 

Parliament. Bellingham, WA, Feb. 18, 2000. 

Meyer, F. P., J. W. Warren, and T. G. Carey (eds.). 1983. A guide to integrated fish health management in 

the Great Lakes Basin. Great Lakes Fisheries Commission Special Publ. 83-2. 

Michak, P., and B. Rogers. 1989. Augmented fish health monitoring. Annual report of the Bonneville 

Power Administration, U.S. Dept. Energy, Portland, OR, 172 p. 

Michak, P., E. Wood, B. Rogers, and K. Amos. 1990. Augmented fish health monitoring. Annual report 

of the U.S. Dept. Energy, 27 p. 

Mighell, J. L. 1981. Culture of Atlantic salmon, Salmo salar, in Puget Sound. Mar. Fish. Bull. 43(2):1-

8. 

Morente, C. 2001. Environmental groups worry about salmon-pen pollution. Bremerton Sun, December 

2. 

Moring, J. R., J. Marancik, and F. Griffiths. 1995. Changes in stocking strategies for Atlantic salmon 

restoration and rehabilitation in Maine, 1871-1993. Amer. Fish. Soc. 15:38-46. 
76

Morton, A. 1997. Whales don’t eat farmed salmon–should we? Natural Life magazine, 

November/December. 

Myers, J., R. G. Kope, G. J. Bryant, D. Teel, L. J. Lierheimer, T. C. Wainwright, W. S. Grant, F. W. 

Waknitz, K. Neely, S. T. Lindley, and R. S. Waples. 1998a. Status review of chinook salmon 

from Washington, Idaho, Oregon, and California. U.S. Dept. Commer., NOAA Tech. Memo. 

NMFS-NWFSC-35, 443 p. 

Myers, M. S., L. L. Johnson, T. Hom, T. K. Collier, J. E. Stein, and U. Varanasi. 1998b. Toxicopathic 

hepatic lesions in subadult English sole (Pleuronectes vetulus) from Puget Sound, Washington, 

U.S.A.: relationships with other biomarkers of contaminant exposure. Mar. Environ. Res. 45:47-

67. 

Nash, C. (ed.). 2001. The net-pen salmon farming industry in the Pacific Northwest. U.S. Dept. 

Commer., NOAA Tech. Memo. NMFS-NWFSC-49, 125 p. 

Neave, F. 1958. The origin and speciation of Oncorhynchus. Trans. Royal Soc. Can. LII (III):25-39. 

Nickelson, T. E., M. F. Solazzi, and S. L. Johnson. 1986. Use of hatchery coho salmon (Oncorhynchus 

kisutch) presmolts to rebuild wild populations in Oregon coastal streams. Can. J. Fish. Aquat. 

Sci. 43:2443-2449. 

NMFS (National Marine Fisheries Service). 1996. Factors for decline [steelhead]. Internet document, 

http//www/nwr.noaa.gov/1salmon/salmesa/pubs.htm#Factors for Decline. 

NMFS (National Marine Fisheries Service). 1998. Factors contributing to the decline of chinook salmon. 

Internet document, http//www/nwr.noaa.gov/1salmon/salmesa/pubs.htm#Factors for Decline. 

NMFS (National Marine Fisheries Service). 2001a. Endangered Species Act Section 7 consultation. 

Draft biological opinion and incidental take statement for 2002, Appendix A–Draft SEIS for 

steller sea lion protection measures. Internet document, 

www.fakr.noaa.gov/protectedresources/stellers/biop2002/draft.htm. 

NMFS (National Marine Fisheries Service). 2001b. Hatchery genetic management plans. Internet 

document, http//www/nwr.noaa.gov/1hgmp/index.html. 

NMFS/USFWS (National Marine Fisheries Service)/U.S. Fish and Wildlife Service). 1984. 

Memorandum of a meeting at USFWS Regional Office, Newton Corner, MA, 23 March 1984. 

Provided by J. Cookson, NMFS, Woods Hole, MA, 1 p. 

NMFS/USFWS (National Marine Fisheries Service)/U.S. Fish and Wildlife Service). 1999. Review of 

the status of anadromous Atlantic salmon (Salmo salar) under the U.S. Endangered Species Act. 

NEFSC, NMFS, Woods Hole, MA, July 1999. 

Noakes, D. J. 1999. Deposition before the Washington Pollution Control Hearings Board, January 14, 1999, 

Olympia, WA. 

Noakes, D. J., R. J. Beamish, and M. L. Kent. 2000. On the decline of Pacific salmon and speculative links 

to salmon farming in British Columbia. Aquaculture 183:363-386. 
77

Northwest Fishing Holes. 2001. Rocky Ford alive with rainbow in the dead of winter. Northwest Fishing 

Holes, December/January. 

NRC (Natural Resources Consultants). 1995, 1996. Artificial propagation of anadromous Pacific 

salmonids, 1950 to present. Contract reports to the U.S. Department of Commerce, NOAA, 

NMFS. Includes electronic databases. (Available from Environmental and Technical Services 

Division, National Marine Fisheries Service, 525 Oregon Street, Portland, OR 97232.) 

NRC (Natural Resources Consultants). 1997. Straying of coho salmon from hatcheries and to streams in 

Hood Canal and Grays Harbor, Washington, during 1995. Natural Resources Consultants, Seattle, 

WA, 75 p. 

NRC (Natural Resources Consultants). 1999. Abundance and stock origin of coho salmon on spawning 

grounds of Lower Columbia River tributaries. Prepared for Pacific States Marine Fisheries 

Commission, Portland, OR, 54 p. 

NWIFC (Northwest Indian Fisheries Commission). 2001. Future brood document. Internet document, 

http://www.nwifc.wa.gov/00fbd/fpspens.trt. 

NWIFC/WDF (Northwest Indian Fisheries Commission/Washington Dept. Fisheries). 1991. Salmonid 

disease control policy of the fisheries co-managers of Washington State. NWIFC/WDF, Olympia, 

WA, 18 p. 

NWIFC/WDFW (Northwest Indian Fisheries Commission/Washington Dept. Fish and Wildlife). 1998. 

Salmonid disease control policy of the fisheries co-managers of Washington State. 

NWIFC/WDFW, Olympia, WA, 22 p. 

ODFW (Oregon Dept. Fish and Wildlife). 1982. Comprehensive plan for production and management of 

Oregon’s anadromous salmon and trout: II. Coho salmon plan considerations. Oregon Dept. Fish 

and Wildlife, Anadromous Fish Section, Portland, OR. 

ODFW (Oregon Dept. Fish and Wildlife). 2000. The facts about Oregon’s hatcheries. Internet 

document, http://www.dfw.state.or.us. 

ODFW/NMFS (Oregon Dept. Fish and Wildlife/National Marine Fisheries Service). 1998. Management 

implications of co-occurring native and introduced species. Proceedings of the Workshop, October 

27-28, Portland, OR. Internet document, www.nwr.noaa.gov/nnative. 

ODIN (Official Documentation and Information from Norway). 2001. Research know how in Norway: 

priority areas–marine research. Internet document, 

http://odin.dep.no/ufd/engelsk/pub/veiledninger/014081-120043/index-hov001-b-f-a.html. 

Parametrix. 1990. Final programmatic environmental impact statement fish culture in floating net-pens. 

Prepared by Parametrix Inc., for Washington State Dept. Fisheries, 115 General Administration 

Building, Olympia, WA 98504, 161 p. 

PCHB (Washington State Pollution Control Hearings Board). 1997a. Testimony before the Pollution 

Control Hearing Board of Washington, Dec. 16, 1997, MEC/WEC v. Ecology, PCHB Nos. 96-

257 through 96-266 and 97-110. 
78

PCHB (Washington State Pollution Control Hearings Board). 1997b. First order on summary judgment, 

PCHB No. 96-257 et seq., NPDES permit appeals, May 29, 1997, 22 p. 

PCHB (Washington State Pollution Control Hearings Board). 1998. Final findings of fact, conclusions 

of law and order, PCHB No. 96-257 et seq., NPDES permit appeals, November 30, 1998, 46 p. 

Pearson, T. H., and R. Rosenberg. 1978. Macrobenthic succession in relation to organic enrichment and 

pollution of the marine environment. Ocean. Mar. Biol. Ann. Rev. 16:229-311. 

Pease, B. G. 1977. The effect of organic enrichment from a salmon mariculture facility on the water 

quality and benthic community of Henderson Inlet, Washington. Ph.D. Dissertation, Univ. 

Washington, Seattle, WA, 145 p. 

Phelps, S. R., S. A. Leider, P. L. Hulett, B. M. Baker, and T. Johnson. 1997. Genetic analysis of Washington 

steelhead: preliminary report incorporating 36 new collections from 1995 and 1996. Washington 

Dept. Fish and Wildlife, Fish Management Division Progress Rep., 29 p. 

Phelps, S., J. Uehara, D. Hendrick, J. Hymer, A. Blakley, and R. Brix. 1995. Genetic diversity units and 

major ancestral lineages for chum salmon in Washington. In C. Busack and J. B. Shaklee (eds.), 

Genetic Diversity Units and Major Ancestral Lineages of Salmonid Fishes in Washington, p. C1-

C55. Washington Dept. Fish and Wildlife, Fish Management Program, Resource Assessment 

Division Tech. Rep. No. RAD 95-02. 

PNWFHPC (Pacific Northwest Fish Health Protection Committee). 1988a. Report on current disease 

status and historical occurrence of important disease problems from hatcheries operated by tribes 

that make up the Northwest Indian Fisheries Commission. Olympia, WA, 18 p. 

PNWFHPC (Pacific Northwest Fish Health Protection Committee). 1988b. Report on current disease 

status and historical occurrence of important disease problems in U.S. Fish and Wildlife Service 

hatcheries. Olympia, WA, 16 p. 

PNWFHPC (Pacific Northwest Fish Health Protection Committee). 1988c. Report on current disease 

status and historical occurrence of important disease problems in Washington Dept. Wildlife 

hatcheries. Olympia, WA, 21 p. 

PNWFHPC (Pacific Northwest Fish Health Protection Committee). 1988d. Report on current disease 

status and historical occurrence of important disease problems in Washington Dept. Fisheries 

hatcheries. Olympia, WA, 17 p. 

PNWFHPC (Pacific Northwest Fish Health Protection Committee). 1993. Fish health status reports 

1988-1992. Pacific Northwest Fish Health Protection Committee Meeting at Twin Falls, ID, 

September 28-29, 1993. 

PNWFHPC (Pacific Northwest Fish Health Protection Committee). 1998. Fish health status reports 

1998. Pacific Northwest Fish Health Protection Committee Meeting at Las Vegas, NV, February 

18-19, 1998. 

Port of Seattle. 2001. Port of Seattle web site: http://www.portseattle.org. 

PSGA (Puget Sound Gillnetters Association). 2000. Warning–wear gloves to handle Atlantic salmon. 

Internet document, http://www.nwefish.com/. 
79

PSWQAT (Puget Sound Water Quality Action Team). 2001. Marinas and recreational boating. Internet 

document, http://www.wa.gov/puget_sound/Programs/Marinas.htm. 

Randall, R. G., J. E. Thorpe, R. J. Gibson, and D. G. Reddin. 1986. Biological factors affecting age at 

maturity in Atlantic salmon (Salmo salar). In D. J. Meerburg (ed.), Salmonid age at maturity. 

Can. Spec. Publ. Fish. Aquat. Sci. 89:90-96. 

Refstie, T., and T. Gjedrem. 1975. Hybrids between salmonidae species. Hatchability and growth rate in 

the freshwater period. Aquaculture 6:333-342. 

Rensel, J. E. 1988. Environmental sampling at the American Aqua foods net-pen site near Lone Tree 

Point in north Skagit Bay. Prepared by Rensel Associates, Seattle, WA, Pacific Aqua Foods, 

Vancouver, BC, and Washington Dept. Natural Resources, 7 p. 

Ritter, J. A., G. J. Farmer, R. K. Misra, T. R. Goff, J. K. Bailey, and E. T. Baum. 1986. Parental 

influences and smolt size and sex ratio effects on sea age at first maturity of Atlantic salmon 

(Salmo salar). In D. J. Meerburg (ed.), Salmonid age at maturity. Can. Spec. Publ. Fish. Aquat. 

Sci. 89:30-38. 

Rosenberg, R. 1976. Benthic faunal dynamics during succession following pollution abatement in a 

Swedish estuary. Oikos 27:414-427. 

Rosenfield, J. A. 1998. Detection of natural hybridization between pink salmon (Oncorhynchus 

gorbuscha) and chinook salmon (Oncorhynchus tshawytscha) in the Laurentian Great Lakes 

using meristic, morphological, and color evidence. Copeia 3:706-714. 

Ruggerone, G. T., and D. E. Rogers. 1992. Predation on sockeye salmon fry by juvenile coho salmon in 

the Chignik Lakes, Alaska: implications for salmon management. N. Amer. J. Fish. Man. 12:87-

102. 

Sauter, R. W, C. Williams, E. A. Meyer, B. Celnik, J. L. Banks, and D. A. Leith. 1987. A study of 

bacteria present within unfertilized salmon eggs at the time of spawning and their possible 

relation to early lifestage disease. J. Fish Dis. 10 (3):193-203. 

Schnick, R. A. 1992. Registration status report for fishery compounds. Fisheries 17(6):12-13. 

Seeb, J. E., G. H. Thorgaard, and F. M. Utter. 1988. Survival and allozyme expression in diploid and 

triploid hybrids between chum, chinook, and coho salmon. Aquaculture 72:31-48. 

Seiler, D., P. Hannraty, S. Neuheisher, P. Topping, M. Ackley, and L. Kishamoto. 1995. Wild salmon 

production and survival evaluation, October 1993-September 1994. Annual Performance Rep., 

Washington Dept. Fish and Wildlife, Olympia, WA. 

Serdar, D., and J. Cubbage. 1996. Chemical contaminants in Salmon Bay sediments. Wash. Dept. Ecol. 

Publ. 96-343. Olympia, WA. 

Shangle, J. 2001. The great upriver bright hunt. Fishing & Hunting News, Sept. 6-20. 

Shillabeer, N., and J. F. Tapp. 1989. Improvements in the benthic fauna of the Tees Estuary after a 

period of reduced pollution loadings. Mar. Poll. Bull. 20:119-123. 
80

Simon, R. C. 1963. Chromosome morphology and species evolution in the five North American species 

of Pacific salmon. J. Morphol. 112:77-97. 

Simon, R. C., and R. E. Noble. 1968. Hybridization in Oncorhynchus (Salmonidae): I. Viability and 

inheritance in artificial crosses of chum and pink salmon. Trans. Amer. Fish. Soc. 97:109-118. 

Skidmore, D., and K. K. Chew. 1985. Mussel aquaculture in Puget Sound. Washington Sea Grant Tech. 

Rep. 85-4, 57 p. 

Stenson, B. 1998. Net-pen pollution threats get full hearing. Sound and Straits magazine, February. 

Sutterlin, A. M., L. R. MacFarlane, and P. Harmon. 1977. Growth and salinity tolerance in hybrids 

within Salmo sp. and Salvelinus sp. Aquaculture 12:41-52. 

Suzuki Foundation. 2001. Why you shouldn’t eat farmed salmon. Internet document, 

http//www.davidsuzuki.org/files/PSF_Salmon_Brochure.pdf. 

Suzuki, R. and Y. Fukuda. 1971. Survival potential of F1 hybrids among salmonid fishes. Bull. 

Freshwater Fish. Res. Lab. (Tokyo) 21(1):69-83. 

Tabor, R., F. Mejia, D. Low, B. Footen, and L. Park. 2000. Predation of juvenile salmon by littoral 

fishes in the Lake Washington-Lake Union Ship Canal. Paper presented at the Lake Washington 

Chinook Salmon Workshop, November, 2000, Seattle, WA, 14 p. 

Taylor, L. A., P. M. Chapman, R. A. Miller and R. V. Pym. 1998. The effects of untreated municipal 

sewage discharge to the marine environment off Victoria, BC, Canada. Water quality 

international 1998. IAWQ 19th Biennial International Conference; 21-26 June 1998, Vancouver, 

BC, Canada. 

Thomson, A. J. L., and J. R. Candy. 1998. Summary of reported Atlantic salmon (Salmo salar) catches and 

sightings in British Columbia and adjacent waters in 1997. Can Man. Rep. Fish. Aquat. Sci. 2467, 

39 p. 

Thomson, A. J. L., and S. McKinnell. 1993. Summary of reported Atlantic salmon (Salmo salar) catches 

and sightings in British Columbia and adjacent waters in 1992. Can Man. Rep. Fish. Aquat. Sci. 

2215, 15 p. 

Thomson, A. J. L., and S. McKinnell. 1994. Summary of reported Atlantic salmon (Salmo salar) catches 

and sightings in British Columbia and adjacent waters in 1993. Can Man. Rep. Fish. Aquat. Sci. 

2246, 35 p. 

Thomson, A. J. L., and S. McKinnell. 1995. Summary of reported Atlantic salmon (Salmo salar) catches 

and sightings in British Columbia and adjacent waters in 1994. Can Man. Rep. Fish. Aquat. Sci. 

2304, 33 p. 

Thomson, A. J. L., and S. McKinnell. 1996. Summary of reported Atlantic salmon (Salmo salar) catches 

and sightings in British Columbia and adjacent waters in 1995. Can Man. Rep. Fish. Aquat. Sci. 

2357, 29 p. 
81

Thomson, A. J. L., and S. McKinnell. 1997. Summary of reported Atlantic salmon (Salmo salar) catches 

and sightings in British Columbia and adjacent waters in 1996. Can Man. Rep. Fish. Aquat. Sci. 

2407, 37 p. 

Thorpe, J. E. 1986. Age at first maturity in Atlantic salmon, Salmo salar: freshwater period influences 

and conflicts with smolting. In D. J. Meerburg (ed.), Salmonid age at maturity. Can. Spec. Publ. 

Fish. Aquat. Sci. 89:7-14. 

Tully, O., P. Gargan, W. R. Poole, and K. F. Whelan. 1999. Spatial and temporal variation in the infestation 

of sea trout (Salmo trutta L.) by the caligid copepod Lepeophtheirus salmonis (Kroeyer) in relation 

to sources of infection in Ireland. Parasitology 119 (1):41-52. 

Tynan, T. 1981. Squaxin seafarm coho outmigration stomach content analysis. Squaxin Tribal Fisheries 

Tech. Rep., Squaxin Island Tribe, Olympia, WA, 7 p. 

USDOI and USDOC (U.S. Dept. Interior and U.S. Dept. Commerce). 2000. Endangered and threatened 

species: final endangered status for a distinct population segment of anadromous Atlantic salmon 

(Salmo salar) in the Gulf of Maine. FR 65:233, November 17, 2000. 

USFWS (U.S. Fish and Wildlife Service). 1982. Atlas of the spawning and nursery areas of Great Lakes 

fishes, Volume XI–Lake Ontario, p. 1-49. USFWS Biological Services Program Rep. 

FWS/OBS-82/52, September 1982. U.S. Fish and Wildlife Service, Dept. Interior, Washington, 

DC. 

USFWS (U.S. Fish and Wildlife Service). 1984. Fish health protection policy (Title 50), U.S. Fish and 

Wildlife Service, Dept. Interior, Washington, DC, 14 p. plus appends. 

Verspoor, E., and J. Hammar. 1991. Introgressive hybridization in fishes: the biochemical evidence. J. 

Fish Biol. 39(A):309-334. 

Volpe, J. P., E. B. Taylor, D. W. Rimmer, and B. W. Glickman. 2000. Evidence of natural reproduction of 

aquaculture-escaped Atlantic salmon in a coastal British Columbia river. Conserv. Biol.14:899-903. 

Volpe, J. P., B. R. Anholt, and B. W. Glickman. 2001. Competition among juvenile Atlantic salmon 

(Salmo salar) and steelhead (Oncorhynchus mykiss): relevance to invasion potential in British 

Columbia. Can. J. Fish. Aquat. Sci. 58:197-207. 

Waknitz, F. W. 1981. Broodstock programs at Manchester Fisheries Laboratory. In T. Nosho (ed.), 

Salmonid Broodstock Maturation, p. 31-33. Washington Sea Grant Publ. WSG-WO 80-1. 

Waknitz, W. Unpubl. data. NMFS Broodstock Restoration Program spawning records and mortality 

records. (Available from W. Waknitz, NMFS, P.O. Box 130, Manchester, WA 98353.) 

Waples, R. S. 1991. Pacific salmon, Oncorhynchus sp., and the definition of “species” under the 

Endangered Species Act. Mar. Fish. Rev. 53(3):11-22. 

WDF (Washington Dept. Fisheries). 1950. Annual Report for 1949. Seattle, WA. 

WDF (Washington Dept. Fisheries). 1953. Annual Report for 1951. Seattle, WA. 

WDF (Washington Dept. Fisheries). 1954. Annual Report for 1953. Seattle, WA. 
82

WDF (Washington Dept. Fisheries). 1990a. The economics of salmon farming: fish culture in floating 

net-pens. Washington Dept. Fisheries, 1990, Olympia, WA, 15 p. 

WDF (Washington Dept. Fisheries). 1990b. Final programmatic environmental impact statement for fish 

culture in floating net-pens. Washington Dept. Fisheries, Olympia, WA, 161 p. 

WDF (Washington Dept. Fisheries). 1991a. Revised stock transfer guidelines. Washington Dept. 

Fisheries, Olympia, WA, 10 p. 

WDF (Washington Dept. Fisheries). 1991b. Historical production of coho salmon from Washington 

state hatcheries on the lower Columbia River. Submitted to ESA Administrative Record for coho 

salmon, April, 1991, 13 p. 

WDF, WDW, and WWTIT (Washington Dept. Fisheries, Washington Dept. Wildlife, and Western 

Washington Treaty Indian Tribes). 1993. Washington State salmon and steelhead stock 

inventory, 1992. Washington Dept. Fish and Wildlife, 212 p. (Available from Washington Dept. 

Fish and Wildlife, P.O. Box 43151, Olympia, WA 98504.) 

WDFW (Washington Dept. Fish and Wildlife). 1996. Fish health manual. Fish Health Division, 

Washington Dept. Fish and Wildlife, Olympia, WA, 69 p. 

WDFW (Washington Dept. Fish and Wildlife). 1997. Escaped Atlantic salmon provide fishing 

opportunity. WDFW News Release, July 21. Internet document, 

www:wa.gov/wdfw/do/jul97/atlantic.htm. 

WDFW (Washington Dept. Fish and Wildlife). 1999. Atlantic salmon escape. WDFW News Release, 

June 15. Internet document, www.wa.gov/wdfw/do/jun99/jun1599a.htm. 

WDFW (Washington Dept. Fish and Wildlife). 2000. WDFW Hatcheries program: statistics. Internet 

document, http://www.wa.gov.wdfw/hat/hat-stat.htm. 

WDFW (Washington Dept. Fish and Wildlife). 2002. Fishing and shell-fishing rules. Internet 

document, www.wa.gov/wdfw/fish/regs/fishregs.htm. 

WDNR (Washington State Dept. Natural Resources). 1999. Potential offshore finfish aquaculture in the 

State of Washington. Aquatic Resources Division, Dept. Natural Resources, Olympia, WA. 

WDNR (Washington State Dept. Natural Resources). 2000. Aquatic resources policy implementation 

manual. State of Washington, DNR Aquatic Resources Division, Olympia, WA. 

WDNR (Washington State Dept. Natural Resources). 2001. Aquatic lands lease data. State of 

Washington, DNR Aquatic Resources Division, Olympia, WA. 

WDOE (Washington State Dept. Ecology). 1986. Recommended interim guidelines for the management 

of salmon net-pen culture in Puget Sound. Washington State Dept. Ecology, Olympia, WA. 

Weitkamp, L., T. C. Wainwright, G. J. Bryant, G. B. Milner, D. J. Teel, R. G. Kope, and R. S. Waples. 1995. 

Status review of coho salmon from Washington, Oregon, and California. U.S. Dept. Commer., 

NOAA Tech. Memo. NMFS-NWFSC-24, 258 p. 
83

Weston, D. P. 1986. The environmental effects of floating mariculture in Puget Sound. Univ. 

Washington School of Oceanography Rep. 87(16), 148 p. 

Weston, D. P. 1996. Environmental considerations in the use of antibacterial drugs in aquaculture. In D. 

P. Baird, M. Beveridge, L. Kelly, and J. Muir (eds.), Aquaculture and Water Resource 

Management. Blackwell Science Publications, Oxford. 

Weston, D. P., D. G. Capone, R. P. Herwig, and J. T. Staley. 1994. The environmental fate and effects of 

aquacultural antibacterials in Puget Sound. NOAA Grant Publ. No. NA26FD0109-01, 19 p. 

Wightman, J. C., B. R. Ward, R. A. Ptolemy, and F. N. Axford. 1998. A recovery plan for east coast 

Vancouver Island steelhead trout. [Publ. draft.] Ministry of Environment, Lands, and Parks, 

Nanaimo, BC, Canada, 132 p. plus appends. 

Wilkins, N. P., H. P. Courtney, and A. Curatolo. 1993. Recombinant genotypes in back-crosses of male 

Atlantic salmon x brown trout hybrids to female Atlantic salmon. J. Fish Biol. 43(3):393-399. 

Williamson, M. H. 1996. Biological Invasions. Chapman Hall. London, 244 p. 

Wood, J. W. 1979. Diseases of Pacific salmon, their prevention and treatment (Third edition). 

Washington Dept. Fisheries, Hatchery Division Rep., Olympia, WA, 82 p. 

WRAC (Western Regional Aquaculture Center). 1999. Western regional aquaculture industry situation 

and outlook report. Volume 5 (through 1997). WRAC, Univ. Washington, School of Aquatic 

and Fishery Sciences, Box 355020, Seattle, WA 98195. 

Wydoski, R. S., and R. R. Whitney. 1979. Inland fishes of Washington. University of Washington Press, 

Seattle, WA, 220 p. 

Youngson, A. F., J. H. Webb, C. E. Thompson, and D. Knox. 1993. Spawning of escaped farmed 

Atlantic salmon (Salmo salar): hybridization of females with brown trout (Salmo trutta). Can. J. 

Fish. Aquat. Sci. 50(9):1986-1990. 

Zook, B. 1998. Recreational and economic importance of introduced fishes in Washington. In ODFW 

and NMFS (hosts), Management Implications of Co-occurring Native and Introduced Fishes: 

Proceedings of the Workshop, October 27-28, 1998, Portland, Oregon, p. 61-63. (Available from 

Sustainable Fisheries Division, National Marine Fisheries Service, 525 NE Oregon St., Suite 510, 

Portland, OR 97232.) 
Recent NOAA Technical Memorandums NMFS


published by the


Northwest Fisheries Science Center


NOAA Tech. Memo. 

NMFS-NWFSC52	 Meador, J.P., T.K. Collier, and J.E. Stein. 2001. Determination of a tissue and sediment threshold for 

tributyltin (TBT) to protect prey species of juvenile salmonids listed under the Endangered Species Act. 

U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-52, 21 p. NTIS PB2002-103161. 

51	 Emmett, R.L., P.J. Bentley, and G.K. Krutzikowsky. 2001. Ecology of marine predatory and prey 

fishes off the Columbia River, 1998 and 1999. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC51, 108 p. NTIS PB2002-101699. 

50	 Turk, T.A., et. al. 2001. The 1998 Northwest Fisheries Science Center Pacific West Coast upper continental 

slope trawl survey of groundfish resources off Washington, Oregon, and California. U.S. Dept. Commer., NOAA 

Tech. Memo. NMFS-NWFSC-50, 122 p. NTIS PB2002-101700. 

49	 Nash, C.E. (editor). 2001. The net-pen salmon farming industry in the Pacific Northwest. U.S. Dept. 

Commer., NOAA Tech. Memo. NMFS-NWFSC-49, 125 p. NTIS PB2002-100948. 

48	 Meador, J.P., T.K. Collier, and J.E. Stein. 2001. Use of tissue and sediment based threshold concentrations 

of polychlorinated biphenyls (PCBs) to protect juvenile salmonids listed under the Endangered Species Act. U.S. 

Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-48, 40 p. NTIS number pending. 

47	 Johnson, L.L. 2001. An analysis in support of sediment quality thresholds for polycyclic aromatic 

hydrocarbons to protect estuarine fish. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-47, 30 p. 

NTIS number pending. 

46 Stout, H.A., B.B. McCain, R.D. Vetter, T.L. Builder, W.H. Lenarz, L.L. Johnson, and R.D. Methot. 2001. 

Status review of Copper Rockfish, Quillback Rockfish, and Brown Rockfish in Puget Sound,


Washington. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-46, 158 p. NTIS PB2001-105559.


45	 Stout, H.A., R.G. Gustafson, W.H. Lenarz, B.B. McCain, D.M. VanDoornik, T.L. Builder, and R.D. 

Methot. 2001. Status review of Pacific herring in Puget Sound, Washington. U.S. Dept. Commer., NOAA 

Tech. Memo. NMFS-NWFSC-45, 175 p. NTIS PB2001-105561. 

44	 Gustafson, R.G., W.H. Lenarz, B.B. McCain, C.C. Schmitt, W.S. Grant, T.L. Builder, and R.D. 

Methot. 2000. Status review of Pacific hake, Pacific cod, and Walleye Pollock from Puget Sound, 

Washington. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-44, 275 p. NTIS PB2001-105562. 

43	 Methot, R.D. 2000. Technical description of the stock synthesis assessment program. U.S. Dept. 

Commer., NOAA Tech. Memo. NMFS-NWFSC-43, 46 p. NTIS PB2001-105560. 

Most NOAA Technical Memorandums NMFS-NWFSC are available on-line at the 

Northwest Fisheries Science Center web site (http://www.nwfsc.noaa.gov).