The Atlantic sturgeon, the largest and longest-lived fish native to the Chesapeake Bay, may be headed to the federal endangered species list.

A Colorado-based environmental group has filed petitions with two federal agencies saying that the fish is "seriously imperiled" and deserves to be protected as either a threatened or endangered species.

"I think this is a fish they might be able to save," said Jasper Carlton, director of the Biodiversity Legal Foundation based in Boulder, Colo.

Carlton said his group took up the Atlantic sturgeon issue after receiving calls from two different biologists, whom he declined to identify to protect their identity, who expressed concern about the species. After a review, Carlton said he concluded "there was no question. The biologists were right."

The Atlantic sturgeon is in bad shape all along the coast. Many scientists believe that the population that once used the Chesapeake as a spawning ground has been all but wiped out. The Hudson River is considered to have the only viable population remaining along the U.S. East Coast, and reproduction there has fallen sharply in recent years.

But any proposed listing under the Endangered Species Act is likely to trigger opposition from commercial fishermen and from states that regulate those fisheries.

Sturgeon are occasionally caught in nets and other gear aimed at other species, so those activities could face restrictions if sturgeon were listed, said John Field, anadromous species coordinator with the Atlantic States Marine Fisheries Commission, an organization of East Coast states responsible for managing migratory species. Although sometimes caught, Field noted that sturgeon "seem to hold up quite well to incidental handling."

At the same time, some worry that listing the sturgeon could hamper fledgling efforts to restore the giant fish to the Chesapeake, which began with an experimental stocking of hatchery-reared fish in the Nanticoke River last summer.

"It does deserve the title of endangered," said David Secor, of the University of Maryland's Chesapeake Biological Laboratory, who has studied Atlantic sturgeon both in the Bay and in the Hudson River. "It's status is threatened and critical.

"But calling something endangered doesn't necessarily help its conservation, and in some cases it can hinder its conservation," he added. Listing the species, Secor said, could result in additional red tape for restoration efforts, with no additional money.

Richard St. Pierre, Susquehanna River Coordinator for the U.S. Fish & Wildlife Service who has worked with sturgeon for years, noted that the shortnose sturgeon had been listed as endangered for two decades, and a recovery plan for the species is only now about to be released.

"People basically just aren't spending money on the shortnose because it's not a valuable species," St. Pierre said.

Others contend that listing could bring more attention to the species and bolster protection and restoration efforts in the Bay and elsewhere. "I can't imagine it [the Chesapeake] not fitting into a recovery plan," said Paul Nickerson, chief of the USF&WS's Endangered Species Division in its Northeast section, which includes the Bay states.

The petition, filed May 29, triggers a 90-day period in which the USF&WS and the National Marine Fisheries Service must determine whether sufficient information has been provided to warrant a status review of the species.

The petition was filed with both agencies because it is unclear which has jurisdiction over the sturgeon. It is an anadromous fish that spawns in the rivers -where species are usually under the jurisdiction of the USF&WS-but lives most of its life off the coast where they are the domain of the NMFS. Officials at the agencies said they will make a joint response to the petition.

If agency officials agree the petition warrants a status review, they would have one year to review existing data, and possibly gather additional information, to determine whether the species should be listed as threatened or endangered. An endangered species is one that could become extinct in the foreseeable future, while a threatened species is one that could become endangered.

If the officials agree the species should be listed, they would develop a proposed rule at the end of the one-year period, which would be subject to comment for up to another year, after which a final decision would be made.

If it were listed, a team would convene to write a recovery plan for the species. The success of the effort, most agree, would hinge in part on whether any money would be available to implement the plan.

Carlton said his organization, which has been involved in several endangered species issues, would file a court challenge if the agencies do not conduct a status review and list the species. "I can say that absolutely authoritatively," he said.

"I don't think we ran into a single scientist who would say the Atlantic sturgeon was not at least biologically threatened," he said. "Most said it was biologically endangered. In other words, we could lose it in the foreseeable future."

Atlantic sturgeon are the largest and longest-lived fish native to the Bay. Adult females average about 8 feet in length; adult males are generally a couple of feet shorter. Adults can weigh from about 100 pounds to several hundred pounds. The largest Atlantic sturgeon on record, caught in Canada, was a 14-foot female, weighting 811 pounds. Individuals can live 60 years or more.

The remnant of an ancient species, sturgeon are sometimes called "the fish that swam with the dinosaurs." They do not have scales, but are instead covered with armor-like bony shields, called scutes, that give them a unique appearance.

Sturgeon were abundant during colonial times and helped to sustain the first colonists during periods of food shortages. Before Jamestown colonists began exporting tobacco to England, they shipped sturgeon eggs, making caviar the first cash crop from the colony.

In the late 1800s, sturgeon became one of the most valuable fisheries in the Bay and along the East Coast, supplying European demand for caviar and sturgeon meat. Bay sturgeon landings peaked at 725,000 pounds in 1890. But the fish are so slow to reproduce, they were rapidly overfished and the population crashed. By 1920, the catch had fallen to 22,800 pounds.

Females in the mid-Atlantic do not reach maturity until they are 10-20 years old, and then they spawn only once every two to six years. As a result, efforts to rebuild the stock would be protracted - biologists say it could easily take more than 50 years.

Today, scientists believe there is no longer a viable native Bay sturgeon population-if there is any at all. Fish surveys have found few signs of reproduction in the Bay in decades, though Secor said a 5-inch Atlantic sturgeon was reported in the James River this year.

In recent years, the Hudson River supported the only active sturgeon fishery, but that was closed two years ago because of poor reproduction.

Today, the sturgeon fishery is closed in all East Coast states except in Connecticut and Delaware where the legal minimum size for sturgeon is 7 feet. "Those states have no reported landings in recent years," Field said.

He said an ASMFC Atlantic Sturgeon Technical Committee has been developing a new management plan for the species that will probably close any Atlantic sturgeon fishery on the East Coast for decades to allow stocks in the Hudson River and in South Carolina-where some sturgeon also remain-to rebuild. The plan would likely include restoration efforts in some areas, including the Chesapeake, where the species has been wiped out, Field said.

In fact, several fisheries scientists around the Bay have been developing a restoration plan for the sturgeon in the Chesapeake which would be based on using eggs obtained from fish outside the Bay in a hatchery for release.

In an experimental project last July, more than 3,000 sturgeon reared at the USF&WS's Northeast Fishery Center in Lamar, Pa., were released into the Nanticoke River by the Maryland Department of Natural Resources.

By mid-June of this year, more than 200 of the tagged fish had been captured in fishing gear, retagged by biologists, and released. "It's a phenomenal return rate," said Ben Florence, program director for aquaculture and hatcheries with the DNR. "We don't expect that with any species. The survival must have been pretty good."

Some worry that listing the species as endangered could imperil the future of sturgeon restoration work in the Bay, as any hatchery-rearing operation could come under intense scrutiny, and some scientists may oppose the idea of using Hudson River sturgeon in the Bay because, genetically, they may be slightly different than the native Chesapeake fish, should any still exist.

"I work with everyone here on the East Coast and we talk about what's going to happen if someone petitions for a listing," St. Pierre said. "Our general feeling is it would be a good candidate for listing-as good as any-but we'd rather that didn't happen because it just ties your hands for doing almost everything. Simple things like our experimental stocking program in the Chesapeake would just come under a horrendous amount of scrutiny, and maybe even be killed because of concern over the genetics of the fish."

Nickerson, though, said hatchery efforts might be required under any recovery plan developed for the species. "Virtually every other fish that is in trouble has a hatchery component in its recovery plan," he said.

But Carlton agreed that if the species is listed, hatchery rearing would likely come under stricter scientific oversight to prevent "sloppy work" which could result in a large numbers of deaths among reared fish. He supported restoration efforts throughout the fish's historic range, but said restoration efforts should include improvements in degraded habitat.

"We want recovery in as much of the known historic range as is reasonably possible," Carlton said. "If you have got dams and terrible rivers that can't be cleaned up, I understand there is a reality there.

"What I hope happens is that this effort produces benefits for the fish," he said. "I hope that it produces more support for the research we need to do. And I hope it beefs up the recovery effort.

"It's going to be a long-term program," he said. "It's going to be real tough."