Saying it is impossible to predict whether Asian oysters would be a boon or a bane to the Bay, scientists from around the region and the country are urging officials to put the brakes on plans to begin establishing a Chesapeake population of the species next year.
They say it would take about five years of research to fill “critical gaps” in current knowledge about the poorly studied Crassostrea ariakensis oyster to predict how it would act in the Bay—or even to predict whether an introduction would likely succeed.
That was the same time frame estimated by scientists who reviewed the issue for the National Academy of Sciences last year.
The report, from the Bay Program’s Scientific and Technical Advisory Committee in February, spells out more than two dozen research recommendations regarding issues the scientists said should be addressed before any decision is made.
“We didn’t even include what we thought were low-priority issues,” Jonathan Kramer, director of the Maryland Sea Grant Program, and one of the report’s authors.
The recommendations represent a consensus among more than 50 oyster researchers from across the nation and Bay ecologists who attended a two-day workshop last December.
“What’s important about this document is that it stands as a formal recognition by a very diverse research community of what is needed to reduce uncertainty,” Kramer said. “It was a very honest attempt to be neutral and to say that these are the issues that scientists are concerned about.”
Their time frame is at odds with a Maryland and Virginia proposal to begin establishing a reproducing population of C. ariakensis in the Chesapeake as soon as next year. State and federal officials in January began to develop an Environmental Impact Statement to review the proposal and possible alternatives. The states are seeking a final recommendation on how—or whether—to proceed in early 2005.
The issue has gained urgency as populations and harvests of the native oyster, C. virginica, hit all-time lows in the past two years. By contrast, limited tests using sterile C. ariakensis oysters in aquaculture have shown the foreign species grows fast and withstands diseases that plague the natives, creating a demand for the new species by the seafood industry.
Tom O’Connell, Maryland Department of Natural Resources’ project manager for the issue, said the short time frame for the review has been the single largest issue voiced about the proposal, but said it reflected a desire that the decision process not drag on. “If you don’t put a time line on things, they are going to drag out to the three– to 6-year time frame,” he said. “We’re in a serious condition right now with our oyster reefs and the Bay’s condition.”
The DNR, after meetings with scientists, is spending about $1.4 million, with the Potomac River Fisheries Commission chipping in another $100,000, to fund a dozen research projects over the next year.
That work is focused on learning about how C. ariakensis might act in the Bay, its susceptibility to disease and the behavior of larvae and early life stages of the oyster, as well as developing models of how both the native and non-native species may fare in restoration efforts.
Those projects mesh with ones outlined in the report. But the report also calls for a number of “high priority” studies that would take several years to complete, including research focused on how adult C. ariakensis oysters would act in the Bay.
“We cannot make a decision to proceed based solely on response of juvenile and small oysters if the goal is to evaluate risks and to predict the potential to establish self-reproducing populations,” the report said.
It would take time, the report noted, just to grow the adults for such studies.
A major question, according to the report, is the extent to which C. ariakensis and C. virginica will compete for space and food in the wild. Limited laboratory tests suggest that very young C. virginica outcompete young C. ariakensis for space. But no one knows what would happen in the wild, or how the two species would interact during later life stages. Those studies alone could take two to three years, the report said.
If the two compete for space at a very young age—when there may be lots of C. virginica because they have not yet been impacted by disease—the species that reproduces first may have an advantage. Right now, no one knows which would reproduce first, and whether that would vary under conditions found in different parts of the Bay.
Further, the two species cannot interbreed. If they reproduce at the same time, the report said, the interspecies fertilization that would occur may reduce overall reproduction—potentially worsening the Baywide oyster decline.
It’s possible that while C. ariakensis, itself, is not affected by some diseases, it could act as a reservoir to accumulate disease organisms and pass them on to native oysters or other mollusks. On the other hand, the report said, it’s possible they could serve as a “sink” that would store pathogens and protect other species.
“Doing this research and answering these question is important not only so we don’t make some serious environmental mistake, but also so we know how to do it, and be successful,” said Mark Luckenbach, of the Virginia Institute of Marine Science and one of the authors of the report. “The risk of failing is very high in this, and the investment to do it is big.”
To improve the odds of success, the report said various strains of C. ariakensis should be examined to see which may provide the greatest ecosystem benefits to the Bay, and which provide the least risk. C. ariakensis oysters appear to act and grow differently within their native range. The proposal by the states calls for only using the “Oregon strain,” which was brought to the United States in the 1970s, but the scientists said it’s unknown if that is the best type for the Bay.
One hope for the new oyster is that, if introduced, it would provide reef habitats like those once created by C. virginica. But the report said it is unclear whether all strains of C. ariakensis build reefs. Also, no one knows whether their reefs would provide the same habitat opportunities for native fish and other organisms, or whether C. ariakensis would be more susceptible to predators because their shells are thinner. Those studies could take three to five years, according to the report.
Another concern is that if fast-growing C. ariakensis filter water at a faster rate than C. virginica, it may accumulate human pathogens or E. coli bacteria to a greater degree than C. virginica, potentially leading to more fishery closures around the Bay.
The scientists said it was inevitable that if C. ariakensis becomes established, it would spread beyond the Bay. They said research needs to look at situations the oyster may encounter in those areas in order to gauge its impact.
In all research, the report said, the potential risks and benefits from C. ariakensis should be compared to those that would result from continued efforts to restore both wild, and selectively bred disease-tolerant, strains of native oysters.
“The National Academy of Sciences report concluded that an introduction is likely to be irreversible,” said Denise Breitburg, a Bay scientist at the Smithsonian Environmental Research Center in Maryland and one of the report’s authors. “If we are going to take such a big step, which clearly has the potential for risks to native oysters and other organisms in the Bay, we want to be sure that we are making the right decision.”
The report is being submitted for use during the development of the Environmental Impact Statement, but exactly how it will be used in the decision-making process is unclear.
O’Connell said officials would review the report and meet with scientists to discuss whether other studies should be launched. “If there are areas of concern, we want to address those immediately, given that we are already working under a short time line,” he said. He said if too many questions remain unanswered next year, a final decision may be postponed. “Let’s see how far we can go in a year’s time, and what concerns have been addressed, and make a decision whether we can more forward,” he said. “Or, we can determine that more research is needed.”
Maryland Gov. Robert Ehrlich has said an introduction would not go forward unless the plan got a thumbs up from researchers.
“The scientists will come to us at some point, we hope in the near future, and give us a definitive answer,” Ehrlich said at the Bay Program’s Executive Council meeting in December. “If the answer is yes, we go. We begin restoring the oyster population in the Bay and cleansing the Bay in the process. If the answer is no, the answer is no.”