Growth hormone transgenic Atlantic salmon - opportunities, risks, and risk management’

Thursday February 21
08:30

Growth hormone transgenic Atlantic salmon - opportunities, risks, and risk management’

Eric M. Hallerman, Virginia Polytechnic Institute and State University (USA)
Growth hormone-transgenic Atlantic salmon exhibit 4-6-fold growth rate enhancement early in life, 10–20% improvement in feed conversion efficiency, and the prospect of shorter produc- tion time, reduced costs, and increased profit- ability. However, they may pose environmental risk to wild salmon populations and receiving ecosystems. Recent laboratory results showed no difference between transgenics and con- trols regarding oxygen consumption rate as fry, developmental rate, survival until emergence from gravel, fry agonistic behavior, or growth and survival in artificial stream. Following stress due to starvation, low dissolved oxygen, or han- dling, wild-type fish maintained homeostasis more effectively than transgenic fish. Trans-
genics matured as parr less frequently than non-transgenics, and were inferior competitors relative to wild-type parr in terms of nest fidelity, spawn participation, and fertilization success. While knowledge of reproductive fitness of GH-transgenic Atlantic salmon is limited to laboratory replication of natural spawning environments, risk may generally be low, but it is non-zero. Ecological risk would be mini- mized by culturing transgenic fish under strict confinement, suggesting grow-out in land- based culture units combined with reproductive confinement and effective operations manage- ment. The effectiveness and economic viability of aquaculture production under such confine- ment conditions has yet to be assessed