Will Genetically Engineered Salmon Be Coming to Your Dinner Table?

SalmonIt would be historic—and, some say, the start of a journey down a slippery slope—if genetically engineered (GE) salmon is approved by the FDA. This fish would become the first GE animal permitted in the U.S. food chain.  GE plants are already being used. Since the 1990s, we’ve had GE herbicide-resistant soybeans and GE pest-resistant corn, which is not damaged by insects.  Other foods that have been produced with GE technology are sugar beets, potatoes, papayas, and summer squash, but these are not widely available.


Scientists are not in total agreement about the possible impact that GE salmon could have upon the economy, the environment, and human health.  Differences of opinion among experts shouldn’t surprise anyone since predicting the future is always, as best, an educated guess. 


Many experts believe that the introduction of genetically engineered animals into the world’s food supply could be beneficial.  Here, for example, is how food scientist Dr. Joe Regenstein sees it:  “In a world where we are trying to feed a potential population of 9.5 billion people by the middle of the century, the use of high production crops is absolutely essential. This salmon is one of many options being developed to help meet that challenge.  If there is proper research data showing that it is appropriate to use them, the government should permit their use.”


However, advocacy groups worry about unpredictable factors. According to the Boston Globe, some have claimed that it could cause “the eventual decimation of the wild salmon population.”  Fear of damage to wild salmon is widespread even though the proposed sterile GE fish would be raised indoors on land. Still others oppose genetic modifications on moral grounds; they don’t believe in tinkering with the genetic code of animals.


For most of the information in the following Q/As, we thank food scientists Dr. J. Lynne Brown and Dr. Joe Regenstein. Dr. Brown is an expert on GE salmon and the main author of A Consumer Guide to Genetically Engineered Salmon, published by Pennsylvania State University. Dr. Regenstein has done extensive research on fish and is co-author of An Introduction to Fish Technology, published by Van Nostrand Reinhold.


Who is promoting GE salmon?


Aqua Bounty Technologies (a Canadian company) and its U.S. partner have petitioned the FDA to approve the sale of GE salmon in the U.S. The FDA has conducted a safety review. How do matters stand now? An advisory committee has indicated that the company provided good evidence of the safety of its product for human consumption.  However, the committee also recommended more testing before GE salmon is approved.


Why does Aqua Bounty Technologies want to market GE salmon?  


This is not a big fish story.   The goal is not to produce bigger salmon; it is to have them grow faster.  GE salmon reach mature, marketable size in 18 months, instead of the 30 months it takes regular salmon.  There are possible benefits for the industry and the consumer, but it’s impossible to know exactly what will happen because, among other uncertainties, it’s impossible to predict whether consumers will buy it or not. (They may feel queasy about buying an animal food product that’s been genetically tampered with.) Some possible benefits: GE salmon could reduce the demand for wild salmon and allow this depleting resource to rebound.  GE salmon (because it reaches maturity faster) may also be cheaper to produce and more sustainable because less feed is needed and expensive equipment is used more efficiently. Therefore, GE salmon may be more profitable for the industry and possibly less expensive for consumers to purchase.  


However, Dr. Brown does not foresee a savings for consumers.  Here’s her prediction: “It is unlikely that the price of farmed salmon will fall if GE salmon are introduced since Aqua Bounty has to recover its research and petition costs in the price of its fry. This cost to the fish farmer is likely to be passed on to the consumer unless the fish farmer can make savings elsewhere in production.”  On the other hand, Dr. Regenstein feels that the cost of raising the fish would have to be huge to negate the savings from feed and equipment use.


How will this biotechnology benefit consumers?


It may make salmon less expensive, enabling Americans to eat more of this fish, known to be an especially healthy entrée. In addition, GE technology has significant implications for the future. The Boston Globepoints out, “Approval would open the door for a variety of other genetically engineered animals, including a pig that is being developed in Canada or cattle that are resistant to mad cow disease.”


When will the FDA announce its decision?


Dr. Brown offers this explanation: “The FDA released information about their review of Aqua Bounty’s petition in late 2010, and I believe they could find no evidence of possible harm to humans in the data submitted. However, the possible approval of this fish ran into intense opposition from many members of Congress who represent states with a stake in fish farming or wild salmon fishing. The GE salmon grows faster than wild salmon and could create intense competition for other fish farmers and possibly for wild caught salmon. At present, almost two years later, the FDA has not yet made any final decision. I am unable to predict if or when it will be approved.” 


Why is it taking so long for the FDA to make a decision about GE salmon?


Here is Dr. Brown’s answer: “The FDA is examining whether the growth hormone produced in GE salmon is harmful for the GE fish or possibly to humans. The hormone is considered an animal drug, so the veterinary medicine advisory committee is reviewing its safety. The FDA is also looking into the environmental impact of GE salmon.  (More about environmental objections in a later Q/A.) 


Where would GE salmon be raised? 


They would be raised on on-land fish farms, not net-pens in the ocean, with great efforts made to keep any fish from escaping and mingling with natural wild salmon. Nevertheless, some GE fish will escape, says the website Salmon Nation. The impact of these GE fish that grow faster than normal salmon on wild stocks is not clear.”


Are there any economic and/or environmental drawbacks to allowing the farming of GE salmon?


Dr. Brown points out these major drawbacks:


- “The company seeking permission to produce these GE fish would only produce the fry that would then be sold to fish farmers to raise.  Aqua Bounty claims to have a process to produce triploid* fry** (very young fish with three sets of chromosomes instead of two) that are female and sterile. These sterile females could not produce offspring even if they mate with wild fish. The company claims this process produces 99-100% triploid. But even 1% non-conversion is a lot of fry when you are handling millions of eggs. So it is likely that some of the fry will be fertile females. If these make it into the wild, there are great concerns about the effects on normal stocks of salmon. The company claims that its fry will be raised in confined pens so they cannot escape to the wild. Since the fry will be sold all over the world, the company cannot guarantee rearing in confined pens, and there are instances of fish raised in inland farms escaping into waterways.”  [Dr. Regenstein says that regulations would be needed to ensure that purchasers had proper facilities for housing the GE fish. But, Dr. Brown points out, the U.S. or Canada cannot establish regulations on how fish are raised in other nations. That would require an international agreement, which would probably take years to develop.]


- “The FDA is apparently making decisions about the environmental effects of the GE fish. Many environmental groups and members of Congress question whether the agency has the skills to do such an environmental safety determination. Senator Begich, who chairs the Commerce, Science, and Transportation Committee, has held hearings on the environmental impact of the GE fish. He feels that, while the FDA can address the safety aspects, other agencies [for example, the Environmental Protection Agency and the Fish and Wildlife Service of the Department of Interior] should be looking at the environmental impact.”


-  “The effect on the fishing economy in areas of the U.S. where farmed salmon are raised or wild salmon are caught is unknown.”


How are GE salmon created? 


The whole story, in scientific detail, is told in the Penn State source listed below, but here is the general idea: a growth hormone gene from a Chinook salmon (one of 8 species of Pacific salmon), is linked to another gene from a saltwater fish called a pout. The pout grows all year long whereas natural salmon grow only seasonally, mainly in warmer weather.  Linking the pout gene to the Chinook gene and then inserting these genes into the fertilized egg of an Atlantic salmon causes the salmon to grow all year long, therefore, reaching maturity faster.


How does GE salmon differ from the salmon consumers are buying now?  


The information that came out in the hearings indicated that there were no differences in taste, texture, or nutrient content. However, Dr. Brown points out the following:  “Farm-raised salmon does not have the beneficial omega-3 fatty acids that wild salmon contains unless they are fed fishmeal.  Initially, farmed fish are fed soy and corn-based feed that don’t provide omega-3 fatty acids.”  Dr. Regenstein points out that, assuming the salmon is fed fishmeal, the omega-3 level would stay the same as wild fish.


What assurances are there that GE salmon are safe to eat?


One of the members of the advisory committee, Prof. Bruce Chassy (a University of Illinois food scientist) said, “I’d eat the fish if they give me one.  I’d feed it to my grandkids.  I mean there’s nothing they’ve done to this fish that in any way makes it less safe.  It’s a salmon.”  Dr. Regenstein agrees and says, “These changes are no more dramatic than those for plants, and we’ve been eating GE plants for a long time.” 


Dr. Brown’s response to the safety question is quite different: “Data submitted by the company, Aqua Bounty, would have included animal studies to see if there was acute toxicity from the amount of growth hormone in the fish. (Since I have not seen the studies submitted, I cannot judge how good the data presented was.) Studies are submitted to examine what I would call immediate toxic effects. The FDA’s evaluations only promise ‘reasonable certainty of no harm.’ If humans could be affected by long-term, low-dose exposure to GE fish, studies submitted to the FDA are unlikely to detect this. Most scientists would argue that any growth hormone in the flesh of the fish would be destroyed by cooking. However, there could be other unknown effects of the genetic manipulation in the fish, so the long-term safety of eating GE fish (or other GE foods) is not known. The situation is similar to drug approvals.  Often, the side effects of drugs approved by the FDA do not become evident until five or more years of use by the population at large.”


When could GE salmon be in American supermarkets?


The company estimates that, after approval, it could take another 2 years for GE salmon to be ready for sale in supermarkets.


What labeling would be required so that consumers would know if they were purchasing GE salmon rather than regular salmon? 


Consumer groups, environmentalists, and others opposed to the sale of GE salmon told the FDA that it would be irresponsible not to label the modified fish as GE if it is approved for human consumption.  However, according to Dr. Regenstein, this requirement would be inconsistent with our current labeling laws.


* Triploid organisms have three sets of matched chromosomes. Humans are diploid – having two sets of matched chromosomes. Generally triploid organisms cannot breed with their diploid counterparts.


** Fry are the very small fish that hatch from the fertilized egg. They generally still have a yolk sac attached to their body.


Want to read about genetically engineered foods in general?  Click here.




Penn State College of Agricultural Sciences “A Consumer Guide to Genetically Engineered Salmon” by J. Lynne Brown (associate professor of food science) and Wei Qin (graduate student)


J. Lynne Brown, Ph.D., Penn State University, Dept. of Food Science


Joe Regenstein, Ph.D., Cornell University, Dept. of Food Science 


Boston.com Boston Globe  “Fish or frankenfish?  FDA weighs altered salmon”


dailyillini.com “UI prof: Genetically engineered salmon safe for human consumption”


physorg.com “Consumer groups push for label for modified salmon”


salmonnation.com “Genetically Engineered Salmon?” 


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