Biotechnology and Bioinformatics (1+1)

2.2.9. Environmental impact of transgenic fish

The possible impacts from the escape of GM organisms from aquaculture facilities are of great concern to some scientists and environmental groups. Critics and scientists predict that

• GM fish could breed with wild populations of the same species and potentially spread undesirable gene s.
• Transgenic fish that have been modified so as to enable them to withstand wider ranges of salinity or temperature, could be more difficult or impossible to eradicate, similar to an invasive species.
• Escaped transgenic fish could harm wild fish through increased competition or predation.
• Critics fear that GM fish might disrupt the ecology by competing with native fish for scarce resources. The con sequence s of such competition would depend on many factors, including the size of the wild population, the number and specific genetic strain of the escaped fish, and local environmental conditions.

Other potential safeguards also exist.

Only sterile GM fish be approved for culture in ocean pens. Fertilized fish eggs that are subjected to a heat or pressure shock retain an extra set of chromosomes. The resulting triploid fish do not produce normal eggs or sperm, and females do not exhibit maturation of the ovary or reproductive behaviors. Thus, all-female lines of triploid fish are the best current method to ensure non-breeding populations of GM fish.