The Maryland environmentalist who wanted the Chesapeake Bay's native oyster to be protected under the federal Endangered Species Act has withdrawn his petition.

Wolf-Dieter Busch, an environmental consultant, said yesterday that his petition was being used as a "negative poster child" by critics of the Endangered Species Act and that he wanted to "clear up the confusion" regarding his intentions.

Although Eastern oyster populations have been ravaged in the Chesapeake Bay, Busch said, the "endangered" listing probably was not warranted, given that thriving populations exist in such places as the Gulf Coast. He said that a "threatened" listing would be ideal, but because his petition had generated such outrage in the aquaculture industry -- a potential partner in oyster recovery -- he felt it was best to withdraw it.

"The political pressure put on by the watermen and aquaculture industry . . . could impact the reauthorization process for the Endangered Species Act," Busch said.

Busch also said that more genetic research is needed to determine whether the Chesapeake Bay oyster is a separate species from Gulf Coast or other Atlantic varieties but that such research could not be finished before the Jan. 11 deadline to act on the petition.

Busch withdrew the petition in an Oct. 13 letter to the National Oceanic and Atmospheric Administration fisheries service, said fisheries agency spokeswoman Connie Barclay. A team of oyster experts had been working since May on a document about the health of the species and will meet on the subject in St. Petersburg, Fla. The team will finish the project even though the petition has been withdrawn, she said.

"We think it will be a excellent reference for those working to restore the Eastern oyster throughout its native range," Barclay said.

Busch's petition, submitted in January, touched off outrage in the oyster industry from Maine to Louisiana. Lake Cowart Jr., vice president of Cowart Seafood Corp. of Lottsburg, Va., said he was pleased that the petition had been withdrawn. He said that the oyster industry would have been devastated by an endangered listing and that efforts to replenish the species in the Chesapeake might have had to stop.

"I think it was the wrong way to approach a problem," he said. "Certainly what was proposed would probably harm the resource more than help it."