Preventing Genetic Pollution and the Establishment of Feral Populations: A Molecular Solution

Aquaculture animals that escape from farms have the potential to create major environmental problems. These include establishment of potentially destructive feral populations (e.g., Pacific oysters [Crassostrea gigas] in Australia, Atlantic salmon [Salmo salar] in British Columbia) and genetic contamination of wild stocks. The latter includes introgression of foreign genes into natural populations from both hatchery-reared fish and genetically modified fish and invertebrates. Concern about these environmental and genetic effects has already led to restrictions on aquaculture industry development and is likely to grow as demand for genetically improved stocks escalates to fulfill production objectives. To circumvent these problems, we have developed a genetic construct that, when properly integrated into production-line fish or invertebrates, should render individuals functionally sterile outside of hatchery conditions. In the hatchery, however, provision of a simple repressor compound at a particular life-history stage allows the animals to be bred and reared as normal. We are developing this “Sterile Feral” technology for both invertebrate and fish species, and we anticipate practical commercial application within a few years.