Alaska Sen. Lisa Murkowski says she opposes federal approval of genetically engineered salmon “for the health of both consumers and fisheries.” But there is no scientific evidence that suggests GE salmon will pose a significant risk to either.
Murkowski claims GE salmon may “interbreed with the wild stocks, and thus perhaps destroy them.” But GE salmon have been rendered sterile — meaning they can’t interbreed with wild salmon stocks. Geographic and physical confinement measures also limit the likelihood that the GE fish will escape and survive.
As for human consumption, scientists engineered GE salmon to grow faster than non-GE farm-raised salmon by inserting genes from two other fish into the genome of an Atlantic salmon. After these changes, the GE salmon remained nutritionally and physiologically comparable to non-GE salmon, according to Food and Drug Administration’s scientific assessments, so the agency deemed GE salmon “safe to eat.”
FDA Approves GE Salmon
The FDA approved GE salmon – marketed by AquaBounty Technologies Inc. as “AquAdvantage Salmon” – on Nov. 19, 2015. AquaBounty first submitted its application to the FDA in 1995.
By inserting DNA from other fish, the company’s scientists engineered Atlantic salmon to reach market size faster than non-GE farm-raised Atlantic salmon. As per AquaBounty’s FDA application, the GE salmon will only be raised and farmed in inland facilities on Prince Edward Island in Canada and in Panama.
AquAdvantage Salmon was the first GE animal (as opposed to a plant) approved for human consumption in the United States.
However, it’s unclear when the GE fish will reach supermarkets. Back in November, when the FDA approved the product, Ronald Stotish, the chief executive of AquaBounty, told the New York Times that “the salmon would not be in stores immediately because it would take about two years for even these fast-growing salmon to reach market size.”
In January, the FDA also issued a ban on the import and sale of GE salmon until the agency “publishes final labeling guidelines for informing consumers of such content,” the FDA said. The ban was the result of language Murkowski introduced into the 2016 fiscal budget, or omnibus, bill.
False claims about GE salmon have come from politicians on both sides of the party divide. While Murkowski is a Republican, Rep. Jared Huffman, a Democrat from California, has said, for example, that “by approving GE salmon, the FDA is allowing the release of a new hybrid animal that could pose a danger to our wild salmon populations, damage the ecosystems they live in, and undermine our domestic commercial fisheries.”
But Murkowski has arguably been one of the most vocal and active opponents. On her website, she notes the importance Alaska’s fisheries to the economy of her state. According to the Alaska Department of Fish and Game, the “seafood industry contributes 78,500 jobs to the Alaskan economy and an estimated $5.8 billion annually with Bristol Bay sockeye salmon … representing some of the largest salmon … fisheries in the world.” For this reason, Murkowski has “supported Alaska’s fisheries … through legislation and her position on the Senate Appropriations Committee,” as her website says.
The day the FDA approved GE salmon, Murkowski voiced her opposition on the Senate floor, claiming the FDA’s decision was “quite disturbing news to any of us who care about our wild species of salmon.” Specifically, she questioned the FDA’s ability to certify that GE salmon don’t “interbreed with the wild stocks, and thus perhaps destroy them.” In that speech, and later press releases, Murkowski called particular attention to GE salmon’s threat to Alaskan salmon stocks.
Murkowski also said that as someone “who believes that the real thing is the best thing for our families,” she found the FDA’s approval of GE salmon “very troubling.” In fact, she said, “I don’t even know that I want to call it a fish,” and instead referred to the GE salmon as a “frankenfish” and an “organism” generally. Likewise, in a Nov. 23 press release, Murkowski said: “Genetically modifying salmon is messing with nature’s perfect brain food. The real thing is not only the safe choice, but it’s the best thing.”
Most recently, Murkowski said in a March 3 press release: “I still adamantly oppose the FDA’s approval of GE salmon, for the health of both consumers and fisheries.” In this release, Murkowski announced the introduction of her Genetically Engineered Salmon Labeling Act, cosponsored with Alaska Sen. Dan Sullivan and Washington Sen. Maria Cantwell.
This legislation calls for the market name of GE salmon to “include the words ‘Genetically Engineered’ or ‘GE.’ ” It would also authorize “an independent scientific review” of the effects of GE salmon on wild salmon stocks and for human consumption.
We contacted Murkowski’s Washington, D.C., office for clarification on her claims, but we have yet to receive a response. If we do, we will update this article accordingly.
While we take no position on whether GE salmon should be labelled as such, we can say that GE salmon is not likely to pose a risk to the health and safety of humans or wild salmon populations, according to the FDA. The agency based its approval on research primarily conducted by AquaBounty scientists and consultations with independent researchers.
In the next few sections, we’ll break down how AquaBounty engineered its salmon. We’ll also outline the evidence backing the FDA’s decision to approve GE salmon as safe for human consumption and the environment.
AquaBounty first developed a GE Atlantic salmon to reach market size faster than non-GE farm-raised salmon in 1989. This technology shortens the production cycle for Atlantic salmon from 32-36 months to 16-18 months.
To make its rapid-growth salmon, AquaBounty scientists inserted genes from two fish – a Chinook (or king) salmon and an ocean pout – into the genome of an Atlantic salmon. Researchers call this specific DNA sequence the “opAFP-GHc2 construct.”
The largest of all salmon species, the Chinook’s contribution to opAFP-GHc2 codes for a hormone that causes the salmon to grow. But in order to produce this hormone in the first place, the gene must be “turned on” by proteins within the cell. That’s where the ocean pout comes in. This fish’s contribution to the construct codes for a protein that keeps the gene for the Chinook hormone turned on. As a result, the GE salmon grows faster.
But location matters in genetic engineering, too, just like when buying a house. To ensure that opAFP-GHc2 would have the desired effect, AquaBounty scientists inserted it at a location on the Atlantic salmon genome that limits the construct’s ability to influence the function of the fish’s “native” genes.
Still, there’s more to genetic engineering — AquaBounty scientists also had to show that opAFP-GHc2 would remain stable in place and composition over time. In other words, did the construct continue to produce the desired effects in GE salmon after multiple generations or did it change? After looking at the data for seven generations of breeding provided by the company’s researchers, the FDA concluded the construct was stable.
So with this new genetic material, is Murkowski right to imply the GE salmon is not a fish? Not in the slightest.
AquaBounty only used genetic material from fish species to engineer its GE salmon — so it’s definitely still a fish.
Two separate genetic tests also indicate AquAdvantage Salmon is, indeed, still an Atlantic salmon. One of the tests, for example, used a technique called DNA barcoding, which can distinguish species much like a grocery store scanner differentiates products using the Universal Product Code’s black stripes.
AquAdvantage Salmon are also all female and sterile.
AquaBounty scientists bred all female fish by mating what they call “neomales” with females. Neomales are females that have been “masculinized” through the application of testosterone during development. Though they have the DNA of a female, neomales produce sperm instead of eggs. Since the sperm determines the sex of offspring, and the neomale sperm all have female DNA, all offspring from this process develop as females.
While hormone-induced sex change is not possible in mammals, some reptiles and fish do undergo this alteration in the wild.
Lastly, once fertilized, the salmon eggs are “subjected to pressure shock treatment,” which renders them sterile.
The fish’s sterility was one of a number of factors that guided the FDA’s environmental assessment of the GE salmon. In the next section, we’ll explain why the FDA, and major health and environment agencies in Canada, concluded AquAdvantage Salmon would most likely not negatively impact wild salmon populations.
Negligible Environmental Risk
The FDA’s environmental assessment outlined three forms of confinement (biological, geographical and physical) that, taken together, would greatly limit the likelihood that GE salmon would negatively impact wild salmon stocks.
AquAdvantage Salmon are “biologically confined” because they’ve been rendered sterile, as previously explained. This means they can’t interbreed with wild salmon stocks.
AquaBounty’s decision to raise all female stocks was also strategic. In Atlantic salmon, the female initiates the mating process by making a nest with eggs. The male then comes by and sprays the eggs with his sperm. If AquaBounty had created all male, sterile GE salmon, these fish would be capable of tricking wild females into thinking they had successfully reproduced. But mating won’t be initiated in the first place if the population is all female, says the FDA, because GE salmon can’t produce eggs.
Still, the facility in Canada on Prince Edward Island does house some fertile GE salmon for breeding purposes. The FDA’s environmental assessment states: “The greatest potential risk to the environment of the United States would occur in the event of the escape of AquAdvantage broodstock from the PEI facility.” For this reason and others, AquaBounty’s proposal also included geographical and physical confinement measures.
The physical confinements start with the fact that the facilities in Panama and Canada are located inland. Within those facilities, there are also additional physical measures, which can include “the use of mechanical devices, either stationary or moving (e.g., tanks, screens, filters, covers, nets, etc.), or the use of lethal temperatures or chemicals to prevent uncontrolled escape.”
But what if a fertile GE salmon or fertilized eggs still manage to get out alive? Geographical confinement measures also limit the likelihood that they’ll survive and reproduce.
For example, the Canadian facility is located near the Fortune River, which has lacked salmon populations since 2001, according to the FDA’s environmental assessment. The assessment also states that salmon “have not been found in any of the other watersheds on the northeast coast of [Prince Edward Island] in the most recent surveys conducted in 2007 and 2008.”
In addition to housing only female, sterile GE salmon, the Panama facility’s geographical location essentially precludes the possibility of survival and interbreeding. In fact, the FDA’s environmental assessment states: “Even if they were not sterile, mature female AquAdvantage Salmon escaping into the watershed near the grow-out site in Panama would not encounter conspecifics or even closely-related species with which to spawn or interbreed.”
The assessment also notes, “[W]ater temperatures in sections of the lower watershed [near the Panama facility] are at or above the lethal maximum that Atlantic salmon can tolerate for an extended period of time.”
Back in 2010, the FDA organized an external advisory committee to evaluate the human health and environmental risks involved with farming GE salmon. David F. Senior, an emeritus professor of veterinary medicine at Louisiana State University who chaired that committee, told us by email: “If fish escaped from the Panama facility, the physical barriers to access the ocean were daunting plus there was the barrier of salmon being unable to survive in the oxygen levels at that latitude of the Pacific Ocean.”
Thus, with the implementation of biological, physical and geographical confinement measures, the FDA concluded “no effects are expected on the environment of the United States (including populations of endangered wild Atlantic salmon in Maine).”
In 2013, Canadian health and environment authorities similarly concluded: “The likelihood of [GE salmon] exposure to the Canadian environment is concluded to be negligible with reasonable certainty.”
As for Alaskan salmon populations, Senior told us that based on the data the FDA provided the external committee back in 2010, “a threat to Alaskan salmon populations would be remote, perhaps close to non-existent.”
In short, Murkowski’s and others’ claims that GE salmon will negatively affect wild salmon populations are unfounded. There’s always the possibility of “nefarious diversion or freak accident (e.g., plane crash),” says Senior, which is part of the reason why he and the FDA do not claim there is absolutely zero risk involved with raising and farming GE salmon. But by implementing physical, geographical and biological barriers, the GE fish’s threat to the environment is limited.
Safe to Eat
The FDA also states that “it is impossible in the present state of scientific knowledge to establish with complete certainty the absolute harmlessness of the use of any substance” by humans. As a result, it defines “safe to eat” as “a reasonable certainty in the minds of competent scientists that the substance is not harmful under the intended conditions of use.” Accordingly, the FDA has deemed GE salmon safe to eat.
How did the agency come to this conclusion? The FDA broke down the risks associated with eating GE salmon as “direct and indirect effects.” Direct effects would include the risk of eating the growth hormone produced by the opAFP-GHc2 construct or other associated hormones. Indirect effects, on the other hand, result from “opAFP-GHc2 construct or its gene product perturbing the physiology of the animal,” such that the composition or allergenicity of the food produced from GE salmon changes.
In order to evaluate any increased risk, the FDA uses the principle of substantial equivalence, first described by the Organisation for Economic Co-operation and Development in 1993. In a nutshell, the principle states that the “assessment of a novel food, in particular one that is genetically modified, should demonstrate that the food is as safe as its traditional counterpart.” In this case, GE Atlantic salmon’s counterpart would be non-GE farm-raised Atlantic salmon.
To assess any direct risk associated with consuming GE salmon, AquaBounty scientists measured the levels of different hormones in GE salmon and compared them with those in its non-GE counterpart.
To start, the Chinook growth hormone doesn’t pose a risk to humans because “fish growth hormone does not bind to mammalian growth hormone receptors,” says the FDA. This means there’s no way for the growth hormone produced by opAFP-GHc2 to interact with, let alone negatively impact, human biology.
However, AquaBounty scientists did find that GE salmon may have elevated levels of an associated hormone called IGF1 compared with non-GE salmon, though the difference was not “statistically significant.” Still, IGF1 “has been considered as a potential hazard for human consumption,” so the FDA evaluated the “margin of exposure” to the hormone.
A “margin of exposure” takes into consideration the maximum amount of a substance a person might consume daily. Based on estimates of how much salmon Americans eat daily and the maximum amount of IGF1 found in GE salmon, AquaBounty scientists calculated a 330-fold margin of exposure to IGF1 – what the FDA deemed “well within levels of exposure” normally consumed, and, thus, “poses no additional risk.”
As for indirect effects, AquaBounty scientists also collected data on the nutritional profiles of GE salmon and non-GE salmon. This includes comparing the quantities of vitamins, minerals, amino acids and the like in the two fish. The FDA, in its analysis of that data, found that the nutritional profiles of GE salmon and non-GE salmon were similar, with one exception. The GE salmon had slightly elevated levels of vitamin B6. In extreme amounts, vitamin B6 can be toxic.
As a result, the FDA calculated another “margin of exposure” analysis for vitamin B6 intake from GE salmon, which came out to be “49.0 fold less than the maximum allowable consumption level.” Accordingly, the agency concluded that “vitamin B6 provides no additional food consumption hazard compared to non-GE Atlantic salmon.”
In her Nov. 19 Senate address, directly after stating that the FDA’s approval of GE salmon was “disturbing news to any of us who care about our wild species of salmon,” Murkowski said wild salmon are “a pretty extraordinary source of omega-3 fatty acid.” This is correct. But by following one statement with the other, Murkowski implied that GE salmon cannot also provide consumers with these nutrients. This is false.
The FDA found that an examination of the GE salmon’s “omega-3/omega-6 ratios showed that they were virtually identical” to those of non-GE salmon. Omega-3 and omega-6 fatty acids are essential to maintaining many basic functions of the human body.
Lastly, the FDA assessed any increased allergenicity in GE salmon compared with its non-GE counterpart. In general, however, the FDA admitted: “There are a great number of uncertainties when attempting to assess potential changes in the levels of allergens in commonly allergenic foods, including salmon.” Consequently, the study conducted on the allergenicity of GE salmon had limitations.
Still, the FDA did not find that the “allergenic potency” of AquAdvantage Salmon was significantly different from that of non-GE salmon.
The agency also consulted with Dean Metcalfe, chief of the Laboratory of Allergic Diseases at the National Institute of Allergy and Infectious Diseases. He also confirmed that individuals vary in their allergenicity to specific foods, including salmon, which makes it difficult to pinpoint any threshold for allergens.
He also said that “the major ‘treatment’ for a food allergy is avoidance of the food causing the allergic reaction.” In other words, a person allergic to salmon would avoid eating the fish — GE or otherwise. “Based on this consultation, FDA identified no additional concerns regarding the allergenicity of food from [GE salmon] beyond those associated with food from non-GE Atlantic salmon.”
Alison Van Eenennaam, an animal genomics and biotechnology expert at the University of California, Davis, agrees with Metcalfe. She told us by email: “If you do not know what level of an endogenous allergen is acceptable or unacceptable then there is no way to interpret the results.” She added, “We do not do this testing on conventional food and the levels tested were clearly within normal biological range of variation for fish.”
In general, Van Eenennaam, who states that she has no competing financial interests with regard to GE salmon, said that, when it comes to human health, GE salmon pose “no different risk” than conventionally bred salmon.
In sum, GE salmon is a certified Atlantic salmon that is as safe to eat as a non-GE salmon, according to the available scientific evidence, and poses little threat to wild salmon populations – especially those that live near Alaska. As a result, Murkowski’s criticisms of the fish are unfounded.
Editor’s Note: SciCheck is made possible by a grant from the Stanton Foundation.