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Since the development of the first GE fish in the early 1990s, laboratory researchers and aquaculture companies have concentrated on genetically engineering fish that would grow faster and need less feed. Many research groups have successfully introduced growth hormone genes from human or animal sources into several fish species such as salmon, carp, trout, medaka and tilapia, causing them to grow several times faster than their natural counterparts.
Genetically engineering fish is a high risk technology with potentially disastrous consequences if the GE fish escape into the environment. Fish species used in aquaculture are very similar to wild fish and may survive and reproduce in the natural environment and readily crossbreed with their wild relatives. Whenever a newly introduced gene enhances the mating success of a GE fish while at the same time decreasing the viability of the offspring, a few GE fish could ultimately cause the extinction of healthy, wild populations. This has recently been verified by researchers at the Purdue University in the USA who discovered that even a small number of growth-enhanced GE fish could eradicate a large population of wild fish. Stressing that body size is an important trait for mating success in many fish species, the researchers used computer models based on experimental research and revealed that, due to the mating advantage of growth-enhanced GE fish, the genetically engineered trait will be transferred to the natural population, but reduced offspring viability means that this "Trojan gene" will eventually lead to extinction.
There are other scenarios that highlight the global risks associated with the escape of GE fish into the environment. Since enhancing the growth rate of these fish increases their daily feed requirements, this could have a devastating effect on the natural environment, especially as most fish that are currently being engineered - e.g. salmon, trout, carp and tilapia - are predators.The release of a growth (and hunger) enhanced salmon or carp into a natural environment could load a heavy burden on the native fish populations.
Another trait that is currently being investigated by genetic engineers is tolerance to cold temperatures. This would enable GE fish to survive in areas from which they were previously excluded and compete with native species, therefore adding to the existing global problem in aquatic ecosystems caused by exotic invaders such as zebra mussels in the Great Lakes.
The race to commercialise growth enhanced GE fish is currently being led by the Massachusetts-based US/Canadian company, A/F Protein Inc., which has engineered a growth enhanced Atlantic salmon containing a growth hormone gene from chinook salmon. This "AquAdvantage salmon", as it is called, grows 4 to 6 time faster than ordinary salmon and A/F also claims that it has a higher food conversion ratio and thus needs 25% less feed over the entire life cycle.
A/F Protein is waiting for regulatory approval in the USA, Canada and Chile although no formal regulation appears to exist in the two latter countries. It has also licensed the Îsuper salmonâ to fish-breeders in Scotland and New Zealand.20 A/F Protein has used the same technology to design growth enhanced flounder, trout, arctic char and tilapia.
Other companies are also involved in the drive to commercialise GE fish in USA, Canada, New Zealand, Israel, Thailand, Taiwan, the UK, Cuba and China.
Abalone
Atlantic Salmon
Bluntnose bream
Channel catfish
Chinook Salmon
Coho Salmon
Common Carp
Gilthead bream
Goldfish
Killifish
Largemouth bass
Loach
Medaka
Mud carp
Mummichog
Northern pike
Penaeid shrimp
Rainbow trout
Sea bream
Striped bass
Tilapia
Walleye
Zebrafish
Center for Food Safety GE Fish Campaign
Greenpeace
Friends of the Earth
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