Transgenic Salmon – A Fascinating Fish Story

Terry D. Etherton

Notice anything different between the two salmon in the image above?  The salmon are the same age–the difference is the larger fish is transgenic, and has a much faster growth rate, which is due to the presence the Chinook growth hormone gene (more about this later)!

For 15 years, the Center for Veterinary Medicine (CVM) at FDA has been evaluating reams of data about the safety and efficacy of transgenic salmon produced by AquaBounty Technologies, Incorporated, located in Waltham, MA.  You might wonder why so long?  Especially when, in my opinion, it is clear there are no significant questions of human food safety surrounding the food from fish grown with AquAdvantage salmon eggs, nor are there any question of material difference between fish grown from genetically enhanced salmon eggs and conventionally bred and born salmon, or between farm-raised salmon and those sold as “wild-caught” fish.

In my 35+ years as a scientist, I cannot remember a CVM application that has pended as long as that of AquaBounty.  This product has been before the Center for more than 15 years. Nor can I recall a CVM review that has been as comprehensive and rigorous as that given to AquAdvantage salmon eggs.  However, this review has gone much, much longer than needed.  Much of this delay relates to the quagmire arising from politics, activist groups doing their best to misrepresent the science (and scare consumers and politicians – you have heard this “one” before), and the inherent risk adverse nature of the FDA scientific review process.

The Veterinary Medicine Advisory Committee (VMAC) is an FDA/Center for Veterinary Medicine (CVM) advisory panel which has as its sole purpose to review the science underlying and the center’s review of an application under the New Animal Drug approval (NADA) approval process.  Their most recent meeting to review Aquabounty salmon was held on September 19 and 20, 2010.  My sense is that the fish will be approved in the near future, which will be an important milestone for animal biotechnology.

The recent FDA/VMAC review again prompted the usual response from activist groups that oppose the approval of transgenic salmon, and all other food biotechnologies.  My blog will present the facts about transgenic salmon, based on science, to provide a factually-based context for my opinion, and that of many other scientists, that Aquabounty salmon should be approved by FDA.


The U.S. Food and Drug Administration (FDA) is considering approval of AquAdvantage® Atlantic salmon eggs. These eggs include a gene from the Chinook salmon (my “beloved” growth hormone or somatotropin gene) that provides the fish with the potential to grow to market size in half the time of conventional salmon. This fish would be the first food from a transgenic animal application approved by the FDA.

The FDA must provide premarket approval and examine the environmental impact of any genetically engineered (GE) food animal before it can be made available commercially. Extensive study is required before approval. The FDA will only approve food from GE animals that are safe to eat. The agency’s food safety evaluation looks at the same information recommended by the Codex Alimentarius.

GE animals are regulated under the new animal drug provisions of the Federal Food, Drug, and Cosmetic Act (FFDCA). The elements of this approval process include:

  • Product definition;
  • Molecular characterization of both the recombinant DNA (rDNA) aspect of the animal and its lineage;
  • Comprehensive data on the characteristics of the animal and its health;
  • Safety for human consumption;
  • Demonstration of effectiveness (label claim); and
  • Environmental impact.

Aquaculture Facts
Aquaculture, or fish farming, has increasingly stepped in to fill the gap where capture fishing fails to meet consumer demand. Largely dominated by Asia, the aquaculture industry grew dramatically for decades but recently has begun recently to moderate.

  • Capture fishery production stopped growing in the mid 1980s. Even as consumer demand continues to rise, fisheries worldwide are on the verge of collapse, largely due to overfishing. Overall, 80 percent of world fish stocks are already fully exploited or over-exploited.
  • Aquaculture currently provides 47 percent of fish consumed worldwide.
  • Over the past 50 years, world aquaculture grew dramatically, from 1 million tons in the early 1950s to 51.7 million tons in 2006 – making it a $78.8 billion industry.
  • Aquaculture has maintained an annual growth rate of 8.7 percent worldwide (excluding China) since 1970.

Benefits of Land-Based Aquaculture Systems
Consumer Benefits

Is there a need for a faster-growing fish?
By 2020, the global demand for animal protein is projected to be 20 million tons per year. AquAdvantage® eggs will help address the need for healthy protein by producing more fish in less time compared to current salmon farming techniques. AquAdvantage® Salmon can be grown in contained facilities, which offer environmental advantages compared to historical cultivation methods.

Don’t consumers already have enough salmon?
Salmon is a popular seafood choice, not only for taste, but for the well-documented health benefits. This has increased demand for farmed and wild salmon products that the industry and capture fisheries will not be able to meet.

Are farmed salmon a healthy alternative to wild salmon?
Atlantic salmon is a great source of heart healthy Omega-3 fatty acids. AquAdvantage® eggs are designed for growth in land-based salmon hatcheries that will provide high-quality facility management and control. There is a lower likelihood for the introduction and spread of disease, and a corresponding reduction in the need for disease treatment. In addition, contrary to unsubstantiated claims disseminated by opponents of this Atlantic salmon is a great source of heart healthy Omega-3 fatty acids. AquAdvantage® eggs are designed for growth in land-based salmon hatcheries that will provide high-quality facility management and control.

Environmental Benefits

Can fast-growing salmon help reduce pressures on dwindling wild fisheries?
Many of the world’s fisheries are in distress or in danger of collapse. A 2006 study published in Science predicted the loss of all commercially captured species of fish by 2048 if current fishing practices are maintained. Yet overfishing continues as the demand for seafood increases. The vast majority of Atlantic salmon sold in the U.S. is farmed. Many American wild salmon populations are in steep decline, so much so that commercial fishing runs in West Coast have been closed several times. With closures in early 2009, salmon fishermen lost their livelihood for the second season in a row and the price of wild salmon soared as a result of shortened supply. By providing a ready source of faster-growing fish, salmon grown from AquAdvantage® eggs can help reduce pressure on wild fish stocks.

Won’t the demand for salmon food offset any protection of wild fish stocks?
Accelerated growth means shorter production cycles and more efficient use of feed. The feed conversion rate (i.e. feed efficiency) for AquAdvantage® Salmon is approximately 10% better than other farmed salmon. In addition, there are emerging technologies in the salmon feed industry that use more sustainable foodstuffs for salmon feeds thereby reducing the amount of fishmeal and fish oil used.

Does this fish have any impact on carbon emissions?
Because fresh and frozen fish are flown to markets all over the world, seafood has a large carbon footprint. AquAdvantage® Salmon are designed for on-shore facilities that can be built closer to consumers to reduce the need for energy-intensive shipping and transportation.

Isn’t fish farming bad for the environment?
The contained, land-based systems used by customers of AquAdvantage® eggs are endorsed by most environmental groups as a more environmentally friendly and responsible alternative to traditional sea-cage farming of salmon.

Won’t the fish escape and breed with native populations?
Fish grown from AquAdvantage® eggs are all female and sterile, making it impossible for them to breed amongst themselves. In addition, FDA approval requires them to be grown in physically contained systems, further reducing any potential impact on wild populations.

Business Benefits

How do aquaculture producers benefit?
Faster growth and greater efficiency mean a more efficient use of capital, reduced feed costs and less time to market. Better economics makes interest in land-based culture feasible, which leads to better biosecurity, reduced disease risk and the opportunity to grow salmon closer to markets.

How do restaurants benefit?
The majority of seafood consumed in the U.S. is in restaurants. The AquAdvantage® Salmon developed by AquaBounty will help increase supply to satisfy growing demand with a dependable, high quality product.

American Economic Growth
Aquaculture provides opportunities for U.S. jobs. Today the U.S. imports over 97% of the Atlantic salmon sold to consumers. The introduction of land-based salmon farms in the U.S. would spur investment into this industry in the United States.

3 thoughts on “Transgenic Salmon – A Fascinating Fish Story

  1. The question GregH, about a specific hormone level, refers to IGF1, which activists have magnified into an issue when it is not. The case: IGF1 was measured in 30 AquAdvantage salmon and in 2 distinct control groups also of 30 each. In 24 of the 30 AA salmon the concentration of IGF1 was below the level of quantitation, in 6 fish, it could be found with a mean of 10.26 ng/g and an absolute maximum of 18.43 in 1 fish. By contrast, in one control group, 11 of the 30 fish had measurable IGF1 with a mean of 7.34, and in the other, all 30 fish were below the LLOQ. What does this mean? Well, when seen in light of what is considered “safe” and what else we eat has measurable IGF1, absolutely nothing. For example, in other edible fish, (e.g.,chinook salmon, trout, bream) the IGF1 range is from 5 to 100 ng/g; in Polish Holstein cows the range is 698-1024!
    Finally, to approach what the FDA considers a safety threshold for the consumption of IGF1, a personwould have to consume roughly 150 lbs of AquAdvantage salmon a day. That’s a big job!

  2. I like this fish (wouldn’t even mind if a few “escaped” near where I might be fishing). But, will I like the next one? Is there (and should there be) a logical stopping point to manipulating genomes?

  3. Maybe I’m just bad at gauging these things, but it seems to me like there is an exceptional amount of hubbub surrounding this one. From what I’ve been seeing from the opposition, they are working on the assumption that the salmon is, in some vague way, dangerous, and any indication of the FDA approving it is seen as evidence of them being paid off (or something along those lines). More or less the same basic tactics you see with all GE foods, just replace corn/beet/whatever with salmon, just seems to me like it’s a bit worse on this one.

    I was wondering about one thing though: I read one article somewhere mentioning the FDA finding negligibly higher levels of one supposed carcinogen or another (I forget what it was). Do you happen to know anything about that, like just how much extra it actually is or how the modification accounts for those elevated levels? I just figured by way of baseless assumption that it’s probably like the equivalent to an extra nibble of fish or something like that. I wonder because no doubt certain groups will use it to give their anti-biotech biases a mask of reasonableness with some ‘frankenfish causes cancer’ line.

    Another thing that strikes me along the those lines is you would think that, if those activist groups were not so much against technology but against large companies, as is so often claimed, that this fish would receive some support, as I don’t see any of the major biotech corporations involved here and AquaBounty seems like a fairly minor player. However, that does not seem to be the case one bit.

    I for one look forward to eating it. This reminds me, I’ve gotta pick up a GloFish one of these days…

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