Warning that the native Chesapeake oyster population is in a “downward spiral,” the Virginia Seafood Council has issued a new request to rear 1 million fast-growing, disease-resistant, foreign oysters in the Bay and along the Atlantic Coast.
The council, an industry trade group, is hoping to win approval for the project after a Feb. 25 public hearing before the Virginia Marine Resources Commission. If approved, the sterile, hatchery-reared oysters could be in the water by late spring.
“We may not have them quite that early,” said Frances Porter, executive director of the group. “But as soon as the oysters are ready, we want to be ready to put them in.”
The council last summer submitted a proposal to grow 1 million of the foreign oysters, Crassostrea ariakensis, mostly in the Bay. But it withdrew the proposal after heavy criticism from scientists, environmentalists and a number of resource agencies, who said the experiment could lead to an accidental introduction of the species, with unpredictable consequences for the Chesapeake.
Among their concerns was that the chemical technique used to render the oysters sterile was only about 99 percent effective, meaning 10,000 or more oysters could have been capable of reproduction. In addition, the proposal would have spread the oysters among 39 growers, many of whom had little experience working with aquaculture.
The new proposal sought input from scientists to address problems raised with the original plan. “We provided a lot of input into how the revision should go,” said Stan Allen, director of the Virginia Institute of Marine Sciences’ Aquaculture Genetics and Breeding Technology Center. Allen said it was likely that the proposal would win formal approval from VIMS, which provides scientific advice to the VMRC.
Under the new proposal, the sterile oysters will be produced by VIMS through a genetic process, which is considered to be nearly 100 percent effective. Also, the oysters will be spread among fewer than a dozen growers.
The Chesapeake Bay Foundation, one of the groups that had raised concerns about the proposal last year, indicated that it would likely support the new plan.
“I would give the seafood council a lot of credit for overhauling the proposal and addressing the most significant concerns that were raised last year,” said Bill Goldsborough, senior scientist with the Chesapeake Bay Foundation.
The proposal will trigger a review by a special Bay Program panel required whenever the potential introduction of a nonnative species is being considered in the Chesapeake. A similar panel had sharply critical of last year’s proposal.
The panel’s review will again focus on whether adequate environmental and economic evaluations have been conducted and reviewed to ensure that risks associated with the proposed introduction are acceptably low.
The review will also include the consideration of alternatives to the proposal, including the potential for using native oysters bred to survive disease better than wild oysters. “The Bay Program partners agree that it is appropriate to reactivate the panel to evaluate the proposal,” said Mike Fritz, living resources coordinator with the EPA’s Bay Program Office. He said the panel would seek to complete its review and make any recommendations by the February VMRC meeting.
Seafood industry interest has been growing in both Virginia and Maryland about the potential for using C. ariakensis, a native of Southeast Asia, in the Bay. Diseases have devastated the native oyster population, with Virginia harvests being nearly nonexistent in recent years, and Maryland’s expected to hit an all-time low during the current season.
Virginia tests in recent years have shown C. ariakensis is not affected by the diseases. In addition, the oysters grow faster and taste similar to the native species.
Others are more skeptical about using the oysters, fearing an accidental introduction of a reproducing population in the Bay, which could harm efforts to restore the native oyster population and may impact other species.
Because of such issues, the Bay Program, as well as several state and federal agencies, last year funded a National Academy of Sciences study of both the ecological and economic issues related to using C. ariakensis in the Chesapeake. The results of the study are expected in late spring.
The seafood council views its study as complementary to the NAS review, saying it anticipates the NAS will offer general support for the “gradual development of an industry that is environmentally responsible.”
But it rejected the notion that the experiment should be put off until after the NAS review and subsequent debate within the region about its conclusions. That, the council said, could suspend future commercial trials until 2004. The council said the oysters need to go in the water by late spring, or they will miss most of this year’s growing season.
In its proposal, the seafood council envisions a “brand new” industry in which millions of sterile C. ariakensis oysters will be reared in aquaculture, rather than harvesting native oysters on the bottom of the Bay, as in the past. Eventually, it believes 200 million to 300 million of the oysters could be reared annually in aquaculture.
The council states there is “little or no financial return on planting native oysters in Virginia” because most die of disease before reaching market size, but C. ariakensis “thrives” in the Bay, at least in aquaculture.
Under its proposal, each participant will get about 100,000 oysters, which will remain in the water for nine to 18 months, depending on their growth rate. Oysters would be reared in a range of water conditions to compare their growth, and removed when they reach market size.
All of the growers have at least five years of aquaculture experience. Oysters will be contained in various types of bags and containers to minimize the chance of any escape.
The council has also designed the study to collect quantifiable economic information about growing the oysters.
In another change, the seafood council also plans to hire a project manager to oversee the experiment. The manager would ensure adequate safeguards are in place at all aquaculture sites, and that the promised economic data is collected.
The sterile oysters will be produced by crossing oysters that have been chemically altered to have four sets of chromosomes, known as tetraploids, with oysters with the normal two sets of chromosomes, known as diploids. The result is an oyster with three sets of chromosomes — known as a triploid — which cannot reproduce.
The seafood council last year proposed using oysters that had been chemically altered to have three sets of chromosomes. But the chemical technique for producing triploids is not considered as effective as the breeding technique.
The genetically produced oysters were not available because VIMS did not have enough tetraploid oysters. But it has since produced thousands of the four-chromosome oysters, which Allen said will be able to spawn and produce the sterile triploids by May.