Proposed project: Investigation of resistance of triploid Pacific oysters to the disease MSX and dermo in Chesapeake Bay.

List names addresses, telephone numbers, and area of expertise of the experts you contacted for substantial advice in assessing effects of a proposed experiment and in designing adequate safety measures.

Local official, Virginia Marine Resources Commission Marine ecologist Reproductive Physiologist

Address and Phone No.

Department of Fisheries and Aquaculture Virginia Institute of Marine Science Gloucester Point, VA (804) 234-2222

Rationale:

Risks identified: The Pacific oyster, Crassostrea gigas, is not native to Chesapeake Bay, hence, triploidy will be used as a means of reproductive confinement. Triploid Pacific oysters, however, have shown a high frequency of hermaphroditism, as high as 29% (Allen and Downing, 1990. Performance of triploid Pacific oysters, Crassostrea gigas: gametogenesis. Can. J. Fish. Aquat. Sci. 47:1213-1222). An individual was observed which produced haploid eggs and sperm. The possibility of selfing has not been investigated. Further, recent observations suggest that a considerable proportion of apparently triploid individuals can progressively revert to the diploid condition (Blankenship 1994. Experiment with Japanese oysters ends abruptly. Bay Journal 4 (5): 1-4). Therefore, application of the precautionary principle would have me consult Appendix B of the Performance Standards and practice stringent confinement.

Should it be possible to rule out the possibility of selfing or conventional reproduction, a different pathway through the Performance Standards would lead me to identify much the same set of risks. With exit from the Performance Standards and consulting the Virginia Marine Resources Commission, however, specific requirements for risk management would depend on regulations of the state of Virginia or of other agencies (see recommendations below). The only modification to the parental organism is a change in the number of chromosomes. It is proposed that the oysters will be stocked into a suitable natural ecosystem. Were the oysters to reproduce, it would not be possible to treat the ecosystem to eradicate the young. There are no native species with which Pacific oysters can interbreed; thus, risk is limited to that of introduction of a new species, due to reproduction of individuals for which triploidy turned out to be an ineffective means of sterilization.

Proposed risk management: Although I was routed to consult relevant state and federal agencies, I voluntarily offer the following description of my experimental protocol. Siting of the experiment so as to minimize risk is not an option. Hence, oysters will be held in a tank into which unfiltered Bay water will be pumped - a vertical drop will preclude loss of gametes via influent water. Effluent water will pass through a UV sterilization unit and a filter removing particles smaller than oyster gametes. The tank will be held in a greenhouse - during the breeding season, aerosols from over the tank will be passed through a double screen to remove any larvae which may have become entrained. Equipment used in the facility will not be used elsewhere. Research animals will be killed and stored under freezing conditions for at least 24 hours before disposal. Access to the site will be limited. Personnel will be chosen carefully and thoroughly briefed about risks posed by introduction of the species to Chesapeake Bay.