There are many GE fish under development, often engineered with growth hormones to make the GE fish grow faster enabling them to reach marketable size at an earlier age. * There are numerous concerns over the welfare and environmental impact of these unhealthy, fast growing fish. * The techniques of producing GE fish are crude, and generally involve the random insertion of DNA into the fish genome.This process may disrupt the tightly controlled network of DNA in the fish. Current understanding of the way in which genes are regulated is extremely limited, and any change to the DNA of an organism at any point may well have effects that are impossible to predict or control. There is already concern regarding environmental effects, human health impacts and welfare of intensive fish farming in aquaculture. Fish are known to escape frequently from aquaculture facilities, which can then interbreed with, or displace, native fish populations.There is a high potential for ecological disruption should GE fish escape from aquaculture facilities. Fast growing GE fish could compete for food, disrupting aquatic food webs and ecosystems. * Researchers have shown that GE fish with a growth hormone gene could have a mating advantage due to their increased size. An experimental study was developed (called the ‘Trojan gene’ model), which demonstrated that the release of just 60 GE fish could lead to an extinction of a wild population within only 40 generations. * Contrary to industry claims, sterilisation of GE fish will not be 100 percent effective in a commercial situation, and will not prevent all crossbreeding between GE fish and wild fish. There is widespread opposition to the farming of GE fish in aquaculture facilities, the most economically profitable method of rearing farmed fish. Several governments and intergovernmental organisations have already taken steps to ensure that any GE fish (e.g. for scientific research purposes) are kept in secure, land-based facilities. However, escaped GE fish will not respect national boundaries, GE fish must be considered as global releases by the multilateral environmental agreement, the UN Cartagena Protocol on Biosafety. * In a commercial aquaculture situation, the physical containment of these fish can never be guaranteed. Escapes of GE fish into the aquatic environment could have devastating effects on wild fish populations and biodiversity. Therefore, Greenpeace demands that the genetic engineering of fish for commercial purposes should be prohibited.