Atlantic sturgeon, an ancient fish that once swam in local waters and has since become scarce, has been listed by the federal government as an endangered species, setting in motion a long-term effort to restore the fish to previous levels.

The official classification, announced on Jan. 31, buttresses a coastwide moratorium on catching the fish that has been in effect since 1998. The Endangered Species Act stipulates a prohibition against “take,” which includes “harassing, harming, pursuing, wounding, killing, trapping, capturing, or collecting.”

The NOAA action covers five distinct sturgeon populations along the eastern seaboard. Four of the five are endangered, including those found in the Chesapeake Bay, New York Bight, Carolinas and the South Atlantic. The Gulf of Maine population is listed as threatened. Any one of these populations can swim in Vineyard waters, according to Kim Damon-Randall, acting regional administrator for protected resources with NOAA’s National Marine Fisheries Service. She is charged with overseeing conservation programs for this and other species.

Atlantic sturgeon are, literally, older than dinosaurs and older than the rivers and harbors where they swim. They used to grow to be as long as 14 feet and live for more than 60 years. Now, most are no more than around four feet in length, although some still have been observed in the 12 to 18-foot range. Atlantic sturgeon are so rare here now that a sighting of a sturgeon spotted and photographed in the Charles River recently made it onto the front page of The Boston Globe.

When the coastwide moratorium was imposed in 1998, the Gazette interviewed a number of local fishermen who recalled seeing them, including Everett Poole, Alfred Vanderhoop and Cooper A. Gilkes.

Mr. Gilkes said this week he remembers being a young man and seeing Atlantic sturgeon breach off Wasque.

The fish once dominated the waters from Labrador to Florida. As anadromous fish, like river herring and salmon, they spend most of their lives in the ocean but in spring they swim into rivers and go upstream to spawn. And therein lies one of the sturgeon’s biggest problems.

“Keep in mind that these species are subjected to a number of different threats because of the area they occupy,” said Mrs. Damon-Randall. Going into rivers and streams, many of which are dammed, involves contact with human activity.

“Yet, these fish play an important role [in the ecosystem of waterways]. They bring nutrients from the marine into the environment of freshwater. And they also take it away. Were we to lose these species, that would impact the places where they visit,” Mrs. Damon-Randall said.

Atlantic sturgeon have been on the Massachusetts endangered species list since prior to 1990. “It has always been on our list [since the list was started],” said Tom French, asst. director of the Division of Fisheries and Wildlife, for the Natural Heritage and Endangered Species Program. “The state is the first line of defense, when it comes to endangered species. We list them when they are in trouble here. The federal agencies, the National Marine Fisheries Service and the U.S. Fish and Wildlife Service, get involved when something is in jeopardy of disappearing in a larger, global, area.

“The Atlantic sturgeon is the condor of the marine environment. It is prehistoric. This is an animal that doesn’t breed until it is seven to 16 years of age,” Mr. French said.

“This is one more in a litany of anadromous fish, herring, the salmon and sturgeon, and cod, that in colonial times were unlimited in number. But now we are listing them one after another, as in trouble,” Mr. French said.

With the designation, the federal government will partner with state and local agencies to take steps to protect the fish. Mrs. Damon-Randall said her office with others will try to find further ways to minimize human impact on the fish. This will include fishing industry involvement to help prevent the accidental catching of the fish, working with the New England Fishery Management Council, the Mid-Atlantic Fishery Management Council and the Atlantic States Marine Fisheries Commission.

The Atlantic States Marine Fisheries Commission implemented the moratorium in 1998 for all eastern seaboard state waters. The federal authorities instituted their own moratorium for federal waters in 1999.

“We will be working on a recovery plan, which will involve as many people as possible,” she said. That will include the states and all local interests. The federal government has already embarked on educational programs. One is called “Students Collaborating to Undertake Tracking Efforts for Sturgeon, SCUTES, which is also the name for the fish’s scales. The program is geared toward high school and elementary school students. Its Web site is nero.noaa.gov/prot_res/scutes/sturgeon.htm. They also have a Facebook Web site: facebook.com/usnoaafisheriesSCUTESgov.

Outreach also involves circulating an information sticker that can be put on fishermen’s tackle boxes.

Mrs. Damon-Randall said the fisheries managers will look at a host of tools to help the fish, which will include designating critical habitat, spawning and feeding areas. She said it has been well documented that young Atlantic sturgeon will forage at the entrance to the Taunton River; many years ago the fish spawned farther up the river. Efforts will be made to improve the habitat in all the rivers and estuaries where the fish were known to visit.

“Atlantic sturgeon are now thought to be absent from at least 14 rivers they used historically, with spawning thought to occur in only 20 of 38 known historic spawning rivers,” according to a NOAA press release.

“A lot has already been done in the James River,” which feeds into the Chesapeake Bay, Mrs. Damon-Randall said. It is also a home for striped bass. Fortunately striped bass are in far better shape than other anadromous fish. “They are looking to further improve the spawning area, and doing a lot more,” she said. Matt Ayer, a fisheries biologist with the state Division of Marine Fisheries, advises all fishermen to pay close attention if they catch an Atlantic sturgeon. While it is not illegal to catch an Atlantic sturgeon accidentally, it is illegal to possess or to attempt to take the fish out of the water for any extended amount of time. He said the hook can be removed from the mouth of the fish and released; or if it can’t be removed, the line can be cut as a last resort. “Try to get the hook out of the mouth without taking the fish out of the water. They won’t bite you. They don’t have sharp teeth. They feed on the bottom and vacuum up small benthic invertebrates.

“We want people to report seeing and or catching a fish. You won’t get into trouble letting us know you saw one,” Mr. Ayer said.

Atlantic salmon used to be prolific in the waters of New England. They used to swim side by side with Atlantic sturgeon. The two fish spawned in the Connecticut River.

Now it is a rare moment when a Vineyard fisherman catches a salmon in these waters. Atlantic salmon seem restricted to the waters of Maine only.

Salmon don’t breed in these waters anymore and are rarely seen.

“We don’t want what happened to salmon to happen to Atlantic sturgeon,” Mrs. Damon-Randall said.