Genetically modified organisms (GMOs) result from the insertion or deletion of genes using genetic engineering methods. Transgenic organisms are most common; these are produced by incorporating genes from another species into the genome.
GMO crops such as corn and soybeans are typically engineered to resist disease or herbicides.
A variety of transgenic fish have been developed for research and potential commercialization. The only transgenic animal commercially available to the public in the U.S. is the GloFish™ (Yorktown Technologies, L.P.), the zebra danio (Danio rerio) produced in a variety of fluorescent colors and marketed as an aquarium fish .
Growth-enhanced Atlantic salmon (Salmo salar) is in the approval process for food fish aquaculture. There are also growth-enhanced strains of channel catfish (Ictalurus punctatus) and tilapia (Oreochromis spp.) used in research.
Other traits being researched include increased cold tolerance and the production of proteins for pharmaceuticals in transgenic fishes and improved disease tolerance in oysters.
Although GMOs may have desirable characteristics for aquaculture, many factors must be considered: GMOs have unique risk attributes, U.S. regulations make it diffcult to obtain approval for commercialization, state regulations vary, consumers may resist genetic modifications, and advocacy groups vigorously denounce GMOs.
Producers and trade organizations of non-GMO aquaculture species also may oppose GMOs because of consumer perceptions or other negative effects on markets. All these factors will influence any aquaculture business plan based on GMOs.
The risks GMOs may pose to the environment and to human health will depend on the species, the traits or characteristics altered, the culture system, the geographic region, and the intended market.
If a GMO is also nonnative, it will have risks comparable with any similar, non-native aquaculture species plus any specific risks associated with the genetic engineering technology and the altered trait. If the GMO is a native species or one capable of interbreeding with native species, there will be risks associated with genetic interchange and the potential for a Trojan gene to occur that could drive local wild stocks to extinction (Box 2).
Transgenic ornamental species may be released into the environment by the public, and food species may escape. Food species also must be deemed safe for human consumption. Some GMO species, if they escape, are unlikely to establish in the environment or become problematic, especially if the genetic alteration decreases survival.
Organisms can be engineered to have low survival or reproductive dysfunction. More traditional methods of sterilization, such as triploidy, may be used with some species. Transgenic fluorescent zebra danio is a good example of a low-risk species because it could not survive the cold winters in much of the U.S. and is highly vulnerable to predators.
Other species, such as catfish, salmon or tilapia, have more history of invasiveness and may survive and establish in some areas. Increased cold tolerance could allow tropical species to establish in temperate climates (e.g., increased cold tolerance in tilapia).
Some traits may have mixed effects relative to establishment potential. For example, growth enhancement may give GMO individuals a mating or survival advantage or may increase their vulnerability to predation because they feed more actively.
GMOs are regulated as New Animal Drugs by the U.S. Food and Drug Administration (FDA). As for any new aquaculture drug, the approval process is lengthy and requires considerable data collection and expense.
No GMO fish has been approved by the FDA. Growth enhanced salmon have been in the approval process for more than 10 years. Glofish™ are sold legally because the FDA evaluated them in a separate process, determined that there was no overriding public or environmental risk, and used regulatory discretion to allow their sale.
This is somewhat similar to the legal use of unapproved aquaculture drugs such as low regulatory priority drugs like salt. It is unlikely that regulatory discretion will be used to allow the legal sale of other unapproved GMO species, especially for food fish.
States also regulate GMOs, but most have little experience with this issue. Producers should expect each species, trait, and development technique to require separate, case-by-case approvals. Proposals to culture GMOs will undoubtedly require that a regulatory or policy framework be developed, which is a lengthy process with an uncertain outcome for the applicant.
California bans all GMOs and, based on history with the GloFish™, is unlikely to grant exemptions. Florida, the state where GloFish™ are cultured, has a comprehensive set of procedures and regulations for culturing GMOs through its lead aquaculture regulatory agency, the Florida Department of Agriculture and Consumer Services (FDACS).
FDACS handles applications on a case-by-case basis and uses a scientific advisory panel made up of state agency and university experts in GMOs, genetics, aquaculture, fisheries, invasion ecology, and ecological risk analysis to identify risks and provide specific recommendations on risk management.
Another consideration is the potential for patent infringement. Most GMOs are patented, which may prevent the effective development and marketing of a competing GMO. An attorney knowledgeable in patent law and biotechnology may be a valuable resource to potential aquaculture producers.
A variety of factors such as concerns over food safety, lack of information to make informed decisions, ethical or moral opinions about genetic engineering, the influence of advocacy groups, and a fear of the unknown have caused mixed reactions to GMOs among the public.
Several advocacy groups oppose the development and use of GMOs, especially in food products, and they influence public and political sentiment. Aquaculturists considering the culture of GMOs should understand that advocacy groups may lobby politicians, contact regulatory agencies, and pursue legal avenues to prevent the approval, culture and sale of GMOs or products derived from GMOs. For example, several advocacy groups sued the FDA over legalizing the sale of GloFish™.
Labeling food products as GMOs allows the public to make personal decisions about consuming them but also suggests to some consumers that the products are qualitatively different than and perhaps less nutritious, wholesome or safe than comparable, non-GMO products. If GMO aquaculture products are to be successful in the marketplace following future approval, educational and marketing campaigns may be needed to ensure product acceptance.
Conclusion and recommendations:
Aquaculturists face several emerging issues that may change the way they do business. These include the development of non-native species and new marketing methods for existing species, pathogens and associated diseases, genetic interchange between cultured and wild stocks, and the commercialization of GMOs.
The science is still developing, there is scientific and economic uncertainty, and regulations are changing and frequently increasing in each of these areas. Some concerns caused by these issues are well founded; others are more questionable. Extension faculty and researchers should work together to generate, compile and disseminate the best possible information.
Producers and aquaculture industry groups should discuss these issues with their Extension faculty and learn all they can to more effectively interact with regulatory agencies and politicians to ensure that regulations are reasonable and science-based.
Attention to emerging issues is important when developing new aquaculture business plans and when changing existing practices; but even well-established operations must adapt to changing regulatory requirements.
Author:
Jeffrey E. Hill
