State and federal officials have agreed to extend the timeline for the release of a study examining the potential for introducing a nonnative oyster into the Chesapeake.

The Army Corps of Engineers and the states of Maryland and Virginia in June announced that they have set May 2007 as the latest target to release a draft Environmental Impact Statement for public review.

The states originally proposed an introduction in the summer of 2003, signaling a desire to complete an environmental review examining the risks and benefits of such an introduction, and various alternatives, within a year. But the completion data has repeatedly been pushed back because of a lack of sufficient information about the nonnative oyster, Crassostrea ariakensis, which had been poorly studied.

Limited tests have shown that the foreign oyster grows rapidly in the Bay and is resistant to the diseases that plague the native oyster species. That has created demand from some watermen and some in the seafood industry for the introduction of breeding populations into the Bay. Many have expressed frustration as completion deadlines for the environmental impact statement have been repeatedly set, and missed.

Scientists, environmental groups and others have cautioned against a hasty decision, noting that an introduction of the species would be irreversible.

“While it is critical that the EIS process be firmly grounded in science, with all decisions being based upon peer-reviewed information, it is equally important that the EIS be completed in a timely fashion,” said Virginia Secretary of Natural Resources Preston Bryant.

Bryant said any research not completed by next May could be used “to better refine our oyster management strategies in the future, without compromising our deadline to complete the draft EIS.”

The review is studying the potential of an outright introduction of breeding C. ariakensis, as well as a variety of options, including limiting C. ariakensis to aquaculture, and enhancing restoration efforts with native oysters.

Maryland Department of Natural Resources Secretary Ron Franks said the review would be “the most comprehensive evaluation of native oyster restoration strategies ever performed in the Chesapeake Bay, and possibly of a potential introduction of a nonnative species in the world.”

But scientists and representatives from some federal agencies doubt that the prescribed studies will be completed by May.

Mike Fritz, living resources coordinator with the EPA’s Bay Program Office, said some of the priority research by the Bay Program’s Scientific and Technical Advisory Committee and the National Research Council will still be under way next May.

“We sort of agreed to disagree on the time frame,” Fritz said. “We understand why they want to have a target date, because they are under pressure to have this thing done.”

The National Oceanic and Atmospheric Administration’s Chesapeake Bay Office has been funding a three-year research program that will not be completed until the end of 2007.

“We have a lot of research under way right now,” said Jamie King, an oyster biologist with NOAA’s Bay Office. “We set out a three-year research program and are continuing our research program. There is a clear end date for the research; it is not dragging on.”

Although King said she would be “pleasantly surprised” if adequate information was available to make a decision before all the research is completed, she added that “the work has been revealing a lot of good information and we think it’s worth waiting to put it all in.”

Meanwhile, a survey conducted this spring by the Scientific and Technical Advisory Committee of scientists involved in C. ariakensis research concluded that only one of 22 high-to-moderate priority research questions identified by STAC had been adequately addressed.

The draft findings said that while research on most questions will be completed in late 2007 or early 2008, it would likely take another six months for data analysis and reporting.

STAC also said little work has been done on some important issues, such as how C. ariakensis would likely fare in other areas along the coast. Scientists have said that an introduction in the Bay would likely result in the species spreading elsewhere. Officials in many other states have strongly opposed such an introduction.