Atlantic Salmon Net Pen Recommendations Comments
The public has been asked to provide comments on early scoping decisions regarding the Department of Ecology’s effort to develop new recommendations for managing commercial net pen aquaculture in Washington. We appreciate the Department’s interest in hearing from the public about this contentious issue, and we provide comments specific to Ecology’s scoping effort in the following document starting on page 7. However, we believe it is necessary to step back and first address some broader questions about the wisdom of allowing for-profit companies to produce non-native fish in state waters. This preface to our specific comments focuses on the inherent impacts and risks associated with industrial scale aquaculture in public waters, noting that Washington is the only state on the West Coast that has not forbidden Atlantic salmon net pens in its marine waters.
One theme that transcends all aspects of our specific concerns is a situation created by the lack of government oversight, the industry’s ability to self-regulate, and the industry’s claims of proprietary information. These three factors combine to prevent the citizens of Washington and state agencies from knowing the true impacts of the existing Atlantic salmon net pens. Unless this situation changes, the State of Washington will never be able to properly understand let alone regulate the impacts of an industry that has a robust record of environmental damage everywhere it operates.
Raising Atlantic salmon in the open marine waters of Washington State is a mistake. The presence of Atlantic salmon, concentrated in open water feedlot net pens, places too great a risk on the icons of Washington’s natural heritage: Pacific salmon, Puget Sound, and the rugged Strait of Juan de Fuca and Washington Coast. Land-based alternatives, which impose far fewer costs on the environment, exist and should be the required method of raising farmed salmon in Washington. Below, we describe the specific ways that open water net pen operations impact wild salmon populations, degrade water quality, destroy benthic communities, harm marine mammals, and ultimately harm local economies (for as go our wild salmon and shellfish, so go our local commercial, tribal, and recreational fisheries). We believe that the sum of these impacts to waters of the state, which are held in the public trust, are much greater than the commercial benefits of this industry, and we encourage Washington to follow the lead of every other state on the West Coast and ban Atlantic salmon net pens.
The presence of Atlantic salmon net pens in the open marine waters of Washington puts Pacific salmon at risk. Washington’s wild salmon are in trouble. As the recent report from the governor highlights (Governor’s Salmon Recovery Office 2016), many of Puget Sound’s salmon stocks are in decline – populations of both Chinook salmon and steelhead, which are listed as threatened under the Endangered Species Act (ESA), are below recovery goals and are getting worse. Atlantic salmon net pens amplify viruses and expose Pacific salmon to deadly diseases and pathogens, put these wild salmon at risk through escapes, and likely directly prey on migrating juvenile salmon.
Atlantic salmon net pens expose Pacific salmon to deadly diseases. Episodic disease outbreaks are a regular occurrence in Atlantic salmon net pens. The list of common outbreaks includes Infectious Salmon Anemia (ISA), Piscine Reo-virus (PRV), Infectious hematopoietic necrosis virus (IHNV), Viral hemorrhagic septicemia (VHSV), Vibrio salmonicida, and Renibacterium (Walker and Winton 2010). Because infected fish are kept in open marine waters, pathogens from dead and dying fish can infect wild salmon migrating past the net pens.
In 2012 there was an extended outbreak of IHNV at three Atlantic salmon net pens on the coast of Bainbridge Island. IHNV is one of the most virulent pathogens for salmonids, and for this reason is listed as a “reportable disease” by the World Organization for Animal Health (OIE). It is likely that the high densities of Atlantic salmon in the pens, which are highly susceptible to IHNV, artificially elevated (“bioamplified”) the number of viral particles present in South Puget Sound, increasing the infection risk for wild juvenile salmon. Over a five-month period this massive outbreak killed over two million pounds of Atlantic salmon. During this entire time, infected fish were freely shedding their viral loads into the environment, where wild fish could repeatedly come into contact with this deadly disease. Officials from WA Dept. of Fish and Wildlife (WDFW), our state agency in charge of wild fish health, were originally told by the industry that the outbreak would be contained within a month. However, they were not notified when the outbreak dragged on for over five months through the summer and into the fall. It is unknown how many wild fish were infected as a result of this outbreak because monitoring of impacts to wild fish did not occur.
During this same IHNV outbreak at the American Gold facilities in Rich Passage, WDFW was denied access to the facility to carry out a caged fish study. One of the most pressing research questions related to the impacts of Atlantic salmon net pens on wild species is the extent to which disease outbreaks in these net pens are transmissible to uninfected wild fish. In 2012 WDFW scientists wanted to place uninfected fish from hatcheries into cages dropped into the net pens. After varying periods of exposure, the previously uninfected fish would be tested for the disease. American Gold staff denied WDFW entrance to the facilities, which prevented any study of the outbreak. This happened in public waters during an outbreak of one of the most virulent salmon diseases in the world, which was creating unknown impacts on ESA-listed wild salmon.
Atlantic salmon net pens expose Pacific salmon to deadly parasites. Sea lice (Lepeophtherius salmonis) are a fish parasite native to the Pacific Coast that attach to living fish to feed on their blood, which can kill their fish host. The sea louse life cycle typically occurs in the open Pacific Ocean on adult salmon. In a natural system with no Atlantic salmon net pens, gravid female lice are only present in the marine nearshore when migrating adult salmon return in the fall. However, Atlantic salmon net pens are stocked with high densities of adult fish in closely packed pens, which provides an ideal location for the sea lice life cycle to occur in nearshore waters. Gravid female sea lice present on adult salmon in net pens release millions of infectious larvae (copepodites) into the surrounding environment when juvenile Pacific salmon are migrating out of rivers in the winter and spring (Orr 2007). These sea lice can overwhelm vulnerable salmon fry, and an infection of more than two lice is fatal (Morton et al 2004). In some cases as many as 23 percent of wild juvenile salmon near Atlantic salmon net pens are infected with lethal loads of sea lice (Bateman et al 2016). If salmon net pens in Washington have similar effects, sea lice could have a dramatic impact on wild salmon populations that are already in steep decline.
Atlantic salmon net pens put wild Pacific salmon at risk through escapes and potential ecological impacts. It is widely acknowledged that salmon net pen operations have unintentionally released Atlantic salmon into the waters of the Salish Sea since the introduction of marine net pens in the 1980’s, though the number of escapes has declined as netting and other practices have improved. Concern over the introduction of self-sustaining Atlantic salmon populations from net pen escapes has been downplayed over the years, due in part to the failed attempts by state fish and wildlife departments to intentionally introduce the species into the Pacific Northwest from 1904 to 1991 (Waknitz et al. 2002). However, a study in the Tsitika River (a moderate-sized (42-km mainstem length) remote river system on the northeast coast of Vancouver Island, Canada) found juvenile Atlantic salmon of two size classes present (Volpe et al. 2000). They were confirmed as Atlantic salmon by genetic analysis, and scale analysis suggested that they were the naturally produced offspring of adult Atlantic salmon that had spawned in the river. The study also reported that their dietary intake overlapped almost completely with that of wild salmonids in the river, implying that they were competing for resources with the wild fish.
A more recent study (Fisher, Volpe, and Fisher 2014) found that Atlantic salmon offspring were present in 36.6 percent of the 41 Vancouver Island rivers surveyed over a three year period, and occupancy models (models were used because detection frequency of species at low abundance is imperfect) suggest that Atlantic salmon were present in 97 percent of those rivers and streams occupied by diverse assemblages of Pacific salmon. The authors conclude that the continued low-levels of escaped Atlantic salmon in British Columbia (where salmon net pens are numerous and of a much larger scale than in Puget Sound) pose a threat for the establishment of this invasive species in waters of the Pacific Northwest. The authors also point out that the habitats encountered in British Columbia are common from the coasts of Oregon through Southeast Alaska.
Atlantic salmon raised in net pens directly impact wild salmon and Puget Sound by preying on wild juvenile salmon and forage fish. Like all salmon, Atlantic salmon are voracious predators. Recent underwater video footage from British Columbia shows that salmon in net pens prey on forage fish – an important food source for wild salmon in Puget Sound - that enter their pens. Not only is this predation depleting forage fish populations that are a lynchpin of Puget Sound’s ecosystem, but it is also a direct subsidy from our wild fish populations to the net pen industry.
Given the evidence of forage fish predation, it is likely that wild juvenile salmon are also prey for Atlantic salmon in net pens. Juvenile wild salmon have been shown to rear extensively in nearshore habitats throughout Puget Sound (Fresh 2006). Net pens placed in nearshore waters are in the migratory pathway of wild juvenile salmon and expose these fish to additional predation pressure. This impact is currently unaccounted for in the permitting of Puget Sound’s net pen operations. If it were ever required, seasonal gut content analysis and video monitoring of fish raised in net pens is likely to show net pen Atlantic salmon are eating our wild salmon.
Atlantic salmon net pens indirectly impact Puget Sound’s orca populations. Putting salmon at risk puts orcas at risk because actions that jeopardize our wild salmon populations jeopardize orcas. A primary driver of the decline of the orca population is believed to be a lack of sufficient prey. As detailed above, net pens stocked with non-native Atlantic salmon put wild fish stocks at risk through the spread of disease and parasites as well as predation and escapes.
Atlantic salmon net pens put marine mammals at risk. Open net pens attract natural fish-eating predators such as whales, otters, seals, and porpoises. These marine mammals can become entangled in the netting surrounding the net pen and drown. Other times animals are able to breach predator control nets and make it into the net pens, which can result in the lethal “control” of these animals. At Scottish salmon net pens, 176 seals were recently killed during a two-year period. At salmon net pens just up the coast in British Columbia, fifteen California Sea Lions were shot in 2016 to protect their operations. The Canadian agency responsible for regulating Atlantic salmon net pens (the Department of Fisheries and Oceans) states that the salmon net pen industry has killed almost 6,000 harbor seals, 1,200 California sea lions, and 363 ESA-listed Stellar’s sea lions.
Marine net pens impact wild and commercial, recreational, and Tribal shellfish resources. Operational net pens transform the seafloor directly beneath them into a dead zone full of anoxic sediment with toxic levels of sulfides. Any shellfish at the site are quickly killed, and elevated nutrients and other pollutants impact shellfish within the mixing zone of the net pen. Another major impact of salmon net pens on shellfish resources is the use of a chemical compound called emamectin benzoate (marketed as SLICE) to treat farmed fish infected with sea lice. Emamectin benzoate belongs to a class of chemicals called avermectins, which are poisons that affect nerve cells. The net pen industry delivers SLICE to their manufactured fish as a feed additive. Upon digestion, the drug passes through the lining of the fish’s gut and into its tissues, where it is then absorbed by sea lice attached to the fish’s body. SLICE can begin to control sea lice abundance on fish in as little as a few days. Although SLICE contains emamectin benzoate (0.2 percent), an active ingredient in pesticides, it is classified as a drug because it is fed to the fish rather than applied externally.
SLICE is not a targeted treatment; it affects the skeletal build up of all crustaceans that come into contact with it—including prawns, crab, and shrimp. Also, because of its ability to persist and accumulate in sediments, SLICE could become toxic to other marine life. Its frequent use in Atlantic salmon net pens could therefore jeopardize the livelihoods of coastal fishing communities reliant on wild species.
The label of the pesticide ‘Proclaim’, in which emamectin benzoate is the only active ingredient, provides a clear warning:
“This pesticide is toxic to fish, birds, mammals, and aquatic invertebrates. Do not apply directly to water, or to areas where surface water is present, or to intertidal areas below the mean high water mark. Do not contaminate water when cleaning equipment or disposing of equipment wash water.”
The U.S. Food and Drug Administration has listed emamectin benzoate as an unapproved drug that should not be used on fish destined for consumption in the United States. However, according to Canadian government information, on average this chemical is being used at least once during the production of every salmon raised in net pens in British Columbia – with over 80 percent of this product going to the US market. There is a strong dependency on this drug as salmon producers in BC have used an average of 7,240 kilograms of SLICE per year to treat lice-infested fish since 2005.
Atlantic salmon net pens take advantage of the public commons to dispose of their waste, which has a negative impact on public waters. Much of the toxic pollutants discharged by the industry do not just settle out below the net pens on the sea floor. Rather, much of the fish waste, uneaten pelletized feed, antibiotics, viruses, parasites, and veterinary chemicals used by the industry to treat their product are transported far afield by strong tidal currents. Atlantic salmon net pens raise their product in our free, cold Pacific waters and rely on the free service of ocean currents to dispose of their waste. Fish waste and uneaten food deliver nitrogen into the surrounding environment, contributing to eutrophication and toxic algal blooms. Studies have shown that rockfish living near salmon net pens have elevated levels of mercury contamination, indicating that some of the effects of Atlantic salmon net pen pollution on the environment may be very long-lived (deBruyn et al 2006).
The ongoing presence and proposed expansion of Atlantic salmon net pens in Puget Sound directly contradict the State’s recovery efforts and threatens to undo much of this work. Over the last decade, Washington has committed hundreds of millions of dollars and done significant work to recover and manage Puget Sound. In 2007, Washington created the Puget Sound Partnership to develop and implement a science-based, ecosystem-wide approach to Puget Sound recovery. In 2012, Governor Jay Inslee established a Blue Ribbon Panel to address ocean acidification, a first in the United States. Additionally, Washington recently made the bold move to make Puget Sound a No Discharge Zone.
Unfortunately, the presence and proposed expansion of Atlantic salmon net pens runs counter to the multitude of recovery initiatives that have been implemented in Puget Sound. For example, the State is encouraging the expansion of an industry with an extensive history of polluting Puget Sound, a body of water it just declared a No Discharge Zone. Additionally, the fact that state agencies refuse to take a rigorous, scientific approach to understanding the impacts of Atlantic salmon net pens directly contradicts the science-based approach championed by initiatives like the Puget Sound Partnership.
Atlantic salmon net pens have a long and well-document record of polluting, spreading invasive species, releasing deadly parasites, and infecting wild salmon with lethal viruses. By enabling the ongoing presence and proposed expansion of Atlantic salmon net pens in the Sound, the State risks undoing much of the critical recovery work that has been accomplished in Puget Sound in the last decade.
Alaska, California, and Oregon have all banned Atlantic salmon net pens. These states recognized the damage net pens impose on their wild fish populations. In Alaska, Atlantic salmon net pens are prohibited because the risk of disease infection, parasite exposure, and potential damage to wild salmon is too high. Oregon states that Atlantic salmon net pens are prohibited due to their potential to cause adverse ecological and genetic damage. Similarly, in California net pens are prohibited due to concerns about infection, disease, and impacts on wild fish. Washington is the only state on the West Coast that allows this industry to operate in its waters. And not only does Washington allow Atlantic salmon to be raised in open water net pens, it is actively encouraging industrial expansion of this industry.
Comments Specific to Early Scoping Decisions and the Working Outline
Wild Fish Conservancy believes that Atlantic salmon net pens should be banned in the open waters of Washington State for all of the reasons outlined above. However, we do have comments specific to the Department of Ecology’s effort to develop recommendations for managing net pen aquaculture in Washington. Our comments regarding the draft scoping decisions and the draft writing outline are focused on two main points: 1) This process should result in the development of regulations rather than just recommendations and 2) the Core Planning Team associated with this project needs broader representation with agency staff specialized in resource protection.
1. Development of Recommendations vs. Regulations
We believe this process needs to result in the development of regulations rather than just recommendations. The planning team made the early scoping decision that this process would not result in the development of regulations for RCW or WAC. Rather, it would simply develop a series of recommendations. Given the failure of the Washington Atlantic salmon net pen industry to follow previous guidelines, the lack of monitoring that has occurred under the guidelines, and the additional risk imposed on ESA-listed species by salmon net pens, we believe this is a misguided decision and should be reversed.
In 1986 the Department of Ecology published a series of guidelines intended to regulate the net pen industry. After thirty years, those guidelines have failed in several ways. First and foremost, we can find no evidence that the net pen industry has ever complied with the guidelines. In some instances, the industry blatantly defied the Department’s guidelines such as failing to conduct ecological tests, siting their nets in areas of biological significance, using antibiotics consistently, and exceeding the amount of production that was recommended.
Instead of simply updating guidelines that are likely to be ignored, the Department should establish new regulations that carry the weight of authority and enforceability. There is no reason to believe that new recommendations will change anything about the way the industry operates. Considering that Washington’s Atlantic salmon net pen industry has a thirty-year record of ignoring even the most basic guidelines, we find it highly unlikely that updating these guidelines by transforming them into recommendations will result in responsible environmental operations from the Atlantic salmon net pen industry.
The evidence below that explains this industry’s long history of violating the 1986 guidelines leads us to conclude that developing updated recommendations is an insufficient avenue for managing the environmental impact of the industry. Instead of wasting three years and many taxpayer dollars creating unenforceable recommendations, the Department should create rules that provide the state the duty and power to hold this industry accountable. The Department has both the duty and authority to create regulations that protect and preserve Washington’s natural resources, and the Department is obligated to adequately protect the public’s interests. We strongly recommend that the Department forego investing in the development of ineffective recommendations that are unlikely to do more than provide a false sense of environmental security and instead immediately commit to developing enforceable rules.
The Dept. of Ecology’s existing management guidelines are not being followed by the Atlantic salmon net pen industry and they have not been followed in decades. The guidelines that are not being followed include: 1) maximum fish production limits, 2) the siting of a salmon net pen in endangered species habitat, 3) the siting of a salmon net pen near wildlife refuges, 4) conducting recommended environmental surveys, and 5) the use of antibiotics not approved by the FDA.
- The existing guidelines state that production should not exceed 1,000,000 pounds of fish per nautical mile. However, we know the industry exceeds these limits. During the 2012 IHNV outbreak, American Gold had to remove over 2 million pounds of Atlantic salmon from their pens in Rich Passage, all of which are within a nautical mile.
- The existing guidelines state that no net pens should be sited within 300 feet of habitat for threatened or endangered species. Endangered species (Puget Sound Chinook and steelhead) regularly swim right through the existing salmon net pens with no separation. This puts our ESA-listed species at risk of contracting diseases and parasites and likely constitutes an unaccounted for “take“ under the Endangered Species Act. Moreover, this habitat is used by other ESA-listed species such as orcas, bull trout, and marbled murrelets.
- The existing guidelines state that no net pens should be sited within 300 feet of wildlife refuges or habitats of special significance. However, two net pens at Rich Passage off Bainbridge Island are located within the Orchard Rocks Conservation Area, a “fully protected” marine reserve managed by WDFW, with a third IHN infected net pen in close proximity. Additionally, all three of the Cypress Island Atlantic salmon net pens are located right in the heart of Cypress Island Aquatic Reserve and San Juan County Cypress Island Marine Biological Preserve, both of which are protected waters managed by San Juan County and DNR.
- The existing guidelines recommend that large facilities carry out regular environmental monitoring in order to determine the impacts of these facilities. These surveys include summer diver surveys that document benthic conditions, a benthic infauna surveys, and hydrodynamic assessments. Despite numerous public records requests, we can find no evidence that the recommended surveys have been conducted.
- The existing guidelines recommend that only antibiotics licensed by the FDA for use in food fish should be used, and that antibiotics should be used sparingly and not as a prophylactic. We know the chemical SLICE (ememectin benzoate) was used at the Port Angeles facility to control an outbreak there, despite SLICE not being approved for use by the FDA at the time.
Additional objective monitoring of the environmental impacts of existing salmon net pens in Puget Sound is badly needed, and sufficient monitoring will not occur without regulatory authority. The magnitude of the impact existing net pens have on ESA-listed species and other state trust resources is unknown. Without a strict regulatory framework for monitoring the full range of potential impacts from Atlantic salmon net pens, this will likely be the case moving forward.
During the 2012 IHNV outbreak at the American Gold facilities in Rich Passage, WDFW was denied access to the facility to carry out a caged fish study. One of the most pressing research questions related to the impacts of net pens on wild species is the extent to which disease outbreaks in net pens are transmissible to wild fish in the vicinity of net pens. In 2012 WDFW scientists wanted to place uninfected fish from hatcheries into cages and drop them into the net pens. After varying periods of exposure, the previously uninfected fish would be tested for the disease. American Gold staff denied WDFW entrance to the facilities, and as a result no studies of the outbreak occurred. This happened in public waters while an outbreak of one of the most virulent salmon diseases in the world was occurring and causing unknown impacts on ESA-listed wild salmon. Without the authority of a regulatory framework for environmental monitoring this unfortunate situation could happen during any future outbreak.
A regulatory framework is the best way to ensure that public resources, including ESA-listed salmon species, are protected from the impacts of Atlantic salmon net pens. The State of Washington has invested over $1 billion in salmon recovery projects since 2000. The ESA listing of Puget Sound Chinook and steelhead should have triggered a new environmental impact statement (EIS) to evaluate the full impacts and risks associated with Atlantic salmon net pen operations. Instead, these net pens have continued to operate with unquantifiable impacts on ESA-listed wild fish. The current process needs to result in the development of regulations that require independent third party testing of both net pen raised fish and wild fish so the public and state agencies can understand the potential impacts of pathogens and parasites on ESA-listed salmon and steelhead. The industry has been given thirty years to self-monitor their impacts, and they have proven that they are incapable. A new path forward is needed, especially since the growing body of science continues to show that the risks this industry pose are growing and of substantial consequence.
Cooke Aquaculture’s poor environmental record and their litany of broken promises further supports the need for strong, enforceable regulations rather than simple recommendations. The links below provide just a small sample of Cooke Aquaculture’s long history of broken promises and environmental destruction.
2. Expanding the Core Planning Team
The Core Planning Team associated with this process needs to be expanded to include resource protection staff from appropriate agencies that have the appropriate technical disciplines. Atlantic salmon net pens put Washington’s wild salmon populations at risk, and they also have the potential to impact shellfish resources, harm marine mammal populations, impact seabirds, and compromise the public’s significant investment in protecting and restoring Puget Sound. While the current planning team has staff from agencies and departments that are charged with industry expansion and the permitting of these facilities, it does not have sufficient staff from resource protection divisions of affected agencies as well as any staff from the Department of Natural Resources and the Puget Sound Partnership. Given the potential impact on ESA-listed species and state trust resources, we believe the core planning team needs agency staff responsible for the protection of ESA-listed species from both federal and state agencies. This should include scientists knowledgeable in juvenile salmonid use of nearshore habitat, scientists with expertise in marine mammal protection, sea bird ecologists, and scientists with expertise in shellfish resource protection.
An example of why this perspective is so badly needed can be found in one of the Department of Ecology’s answers in the FAQ section of the project’s webpage. In response to a question regarding the impact of sea lice in Washington’s net pens, the answer states that there are not significant problems with sea lice in Washington’s commercial net pens. This is a classic example of a lack of appropriate ecological perspective. This mindset says, “lice aren’t a problem on farms, so they aren’t a problem.” This overlooks the fact that sea lice from salmon net pens can have a lethal impact on wild juvenile salmon at levels of infection that are not a problem for the fish in net pens. Just because a net pen is not having an outbreak of sea lice that they need to control, it does not mean that there are not impacts on wild juvenile salmon migrating nearby. The net pens still result in additional gravid sea lice in nearshore environments that would otherwise not be there, resulting in an impact on wild fish populations.
Another example is the guidance being provided to this process by the National Center for Coastal Ocean Science (NCCOS). While NCCOS is a line office of NOAA, the federal agency charged with protecting ESA-listed salmonid and orca populations in Puget Sound, NCCOS is not the line office charged with protecting ESA species. That office is the National Marine Fisheries Service. Part of the mission of NCCOS is to support aquaculture. This mission certainly has the potential to minimize or overlook some of the impacts of aquaculture on the environment, or at a minimum make them more willing to accept more risks to the environment than are warranted. In their report titled “Marine Cage Culture and the Environment”, which is being used to guide this process, there is no discussion about the interaction of sea lice propagated by net pen fish on wild fish. Given that this issue has been central to the discussion of Atlantic salmon net pen impacts in the Salish Sea, its omission either signifies a gross ignorance of the ecological issues associated with marine net pen operations, or it is an intentional omission for the purpose of deception. Either way their involvement taints this process.
Bateman, Andrew W, and S.J. Peacock, B. Connors, Z. Polk, D. Berg, M. Krkosek and A. Morton. 2016 Recent Failure to Control Sea Louse Outbreak on Salmon in the Broughton Archipelago. Canadian Journal of Fisheries and Aquatic Sciences
Burridge, L., Weis, J. S., Cabello, F., Pizarro, J., & Bostick, K. (2010). Chemical use in salmon aquaculture: A review of current practices and possible environmental effects. Aquaculture, 306(1-4), 7-23.
Debruyn, A.H., M. Trudel, N. eyding, J. Harding, H. McNalley, R. Mountian, C. Orr, D. Urban, S. Verenitch and A. Mazumder 2006. Ecosystemic effects of Salmon Farming Increases Mercury Contamination in Wild Fish. Environmental Science and Technology 40 (11)
Dethier, M. 2006. Native Shellfish in Nearshore Ecosystems of Puget Sound. Puget Sound Nearshore Partnership Report No. 2006-04. Published by Seattle District, U.S. Army Corps of Engineers, Seattle, Washington.
Findlay, R.H., and L. Watling. Prediction of benthic impact of salmon net pens based on the balance of benthic oxygen supply and demand. 1997 Marine Ecology Progress Series 155 147-157
Fisher, Alina C, John P Volpe, and Jason T Fisher. 2014. “Occupancy Dynamics of Escaped Farmed Atlantic Salmon in Canadian Pacific Coastal Salmon Streams: Implications for Sustained Invasions.” Biological Invasions 16: 2137–46.
Fresh, K.L. 2006. Juvenile Pacific Salmon in Puget Sound. Puget Sound Nearshore Partnership Report No. 2006-06. Published by Seattle District, U.S. Army Corps of Engineers, Seattle, Washington.n.
Governor’s Salmon Recovery Office (2016) State of the Salmon in Watersheds. www.stateofsalmon.wa.gov
Morton A., Routledge R., Peet C., Ladwig A. 2004 Sea lice (Lepeophtheirus salmonis) infection rates on juvenile pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon in the nearshore marine environment of British Columbia, Canada. Canadian Journal of Fisheries and Aquatic Sciences. 61, 147–157
Orr, Craig. Estimated Sea Louse Production from Marine Harvest Canada Farmed Atlantic Salmon in the Broughton Archipelago, British Columbia 2003-2004 . (2007) North American Journal of Fisheries Management 27: 187-197
Volpe, J P, Taylor, E B, D W Rimmer, and B W Glickman. 2000. Evidence of Natural Reproduction of Aquaculture-Escaped Atlantic Salmon in a Coastal British Columbia River. Conservation Biology 14 (3): 899–903.
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. Commerce, NOAA Tech. Memo. NMFS-NWFSC-53.
Walker P. J., Winton J. R. (2010). Emerging viral diseases of fish and shrimp. Vet. Res. 41:51 10.1051/vetres/2010022