Fact Pack

Genetic engineering processes are becoming increasingly common and are being applied to a widening variety of organisms. Genetic modification involves identifying genes scientists hope will express the desired traits when introduced into fish. These new genes can come from other species of animals, plants, bacterium, and even humans.

There are several processes used to insert “new” DNA into fish, ranging from inserting genetic material directly into eggs to subjecting fish eggs to electrical pulses, which form pores and allow foreign DNA to access the eggs. The precise location where the new genetic material has attached to the original DNA is unknown and may vary between individual fish so scientists need to check to ensure the inserted gene is present and determine if it functions as expected. Once scientists have determined that the genes have been inserted, the fish are raised like other farmed fish.

Although this discussion is focused on transgenic fish, other transgenic aquatic organisms, including marine and freshwater plants and shellfish, are being fast-tracked for commercialization.

Genetic engineering technology is being applied with more frequency. These increasingly common practices, coupled with a lack of safeguards and regulations, make state action crucial to protect public and environmental health.

Risks Associated with Transgenic Fish

Food Safety Issues

Potential human consumption of transgenic fish and shellfish raises an assortment of food safety concerns.

• Genes inserted to promote disease resistance may cause transgenic fish to absorb toxic substances (like mercury) at a higher rate(1) and pass these toxic substances on to consumers.
• Roughly 90 percent of food allergies can be attributed to consumption of eggs, fish, shellfish, milk, peanuts, soybeans, tree nuts, and wheat.(2) If proteins used in the production of transgenic species originate from one of these eight sources, there may be potential for allergic reactions among consumers.
• The majority of transgenic fish have been inserted with growth genes.(2) Large doses of growth hormones may pose health risks if consumed in raw and uncooked foods like sushi.

Environmental Concerns

Transgenic fish pose potential threats to natural ecosystems and native species populations that are not fully understood and remain insufficiently studied. However, it is known that:

• Fifty percent of all intentionally introduced fish have had harmful economic or environmental effects(3);
• Sixty-six percent of all unintentionally introduced fish have had harmful economic or environmental effects(3);
• Millions of farmed fish escape from open water facilities each year and contaminate native populations(4); and
• It is inevitable that transgenic fish will escape from aquaculture pens or field trial parameters.(3)

Although these statistics reflect impacts from the releases of non-transgenic fish, the implication is clear – introduction of foreign species to an ecosystem does not occur without negative consequences. The environmental risks of releasing transgenic fish may threaten biodiversity in natural ecosystems and the genetic integrity of those systems.

Genetic alterations in transgenic fish may give them competitive advantages over native species.

• By using growth hormone genes, researchers have been able to increase growth rates 2 to 11 times faster than the normal rate.(5) Faster development leads to earlier sexual maturity and potentially more breeding opportunities than their native counterparts.
• If transgenic fish are genetically enabled to breed earlier and at a faster rate, transgenic genes are more likely to be spread throughout native populations. This would reduce the genetic diversity of the native population.
• Research indicates that transgenic fish may reach maturity faster, but they also die sooner.(6) This “Trojan gene” scenario could have devastating consequences if transgenic fish interbreed with native populations. Additionally, if transgenic genes for rapid growth are correlated with shorter life expectancy, the overall life expectancy for the entire population may be reduced.(6)
• Transgenic fish may have similar effects on natural ecosystems as exotic species. An increased growth rate is often accompanied by a voracious appetite, and transgenic fish may out-compete native species for resources, destroy plants and sensitive habitat, and/or alter the food chain in an ecosystem.

For more information on invasive species see SERC’s package on Stopping the Spread of Invasive Species.

Worldwide Projects

Dozens of genetically engineered fish and shellfish projects are currently underway throughout the world. Genetic engineering is altering the genetics of a variety of species for the purposes of increasing aquaculture production, medical and other research, cleaning up water pollutants, and ornamental reasons. Examples of projects include:

• Inserting genes for increased growth rates and increased resistance to disease in Rainbow trout, tilapia, catfish, grass carp, mollusks, and prawns. These genetic modifications are intended to increase aquaculture productivity for human food consumption.
• Inserting human clotting genes into Tilapia for possible pharmaceutical application.
• Inserting the “anti-freeze” gene into goldfish for research purposes and to add consumer appeal as household pets.
• Algae are being genetically engineered for use as a bioremediation tool. Genetic modification is increasing the algae’s ability to absorb higher levels of toxic heavy metals.(5)

For a list of various aquatic transgenic species projects, visit the Pew Initiative on Food and Biotechnology.

States Can Lead the Way

Although there are no federal regulations for transgenic fish, states can protect the health of their citizens and environment. Many states have existing policies in place that could be modified to regulate transgenic fish:

• Fifteen states have adopted regulations concerning uncontained uses of transgenic fish and other transgenic marine organisms.(2)
• California requires permits for genetically engineered species. One year after its enactment, the state had issued fourteen permits, mostly to universities and research institutes.(7)
• Five states have specifically defined genetically engineered organisms as exotic species.(3)
• The Chesapeake Bay Program – a partnership consisting of five states, the District of Columbia, and the Environmental Protection Agency – defines genetically engineered organisms as exotic species.
• The National Institute of Health created research guidelines for genetic engineering. Some states (and some townships within states) adapted their statutes to control genetic research within their borders.
• States could include permit requirements for transgenic fish within existing aquaculture regulations.
• States could include permit requirements for transgenic fish within their Coastal Management Plan.