Getting to know Atlantic sturgeon isn’t easy.

Case in point: watermen netted a 6-foot, 200-pound spawning female in the James River in April. Thinking it would move toward Richmond to lay its eggs, scientists placed a tracking device in the fish.

It disappeared, presumably with its eggs intact, a day later.

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“Some fish will do that, especially sturgeon,” said Greg Garman, a Virginia Commonwealth University professor who studies the dinosaur-like fish.

Once common in the Chesapeake Bay and other East Coast estuaries, Atlantic sturgeon levels are thought to be a fraction of what they were when settlers arrived in Jamestown more than 400 years ago — victims of overfishing, loss of habitat, pollution and ship strikes.

Conservation groups want the fish listed under the Endangered Species Act. But researchers and multiple state agencies oppose the effort. They favor a less strict designation, which they say will allow them to continue their research and prompt fewer restrictions on commercial fisheries.

Species decline

Sturgeon are best known for two things: the bony plates, known as “scutes,” on their back and sides; and their eggs, which are sold as caviar.

There are two sturgeon native to Virginia waters, the shortnose and Atlantic. Shortnose sturgeon, which are rarely found in the bay and its tributaries, are an endangered species.

Efforts to determine how many Atlantic sturgeon exist have been thwarted by the fish, which move between the ocean and brackish waters, and a lack of funding, Garman said.

A 2007 report from the National Oceanic and Atmospheric Administration estimated there were fewer than 300 spawning females in the James. The population in other bay tributaries, including the York, Rappahannock and Potomac rivers, is smaller, the report said.

There are a variety of reasons for the species’ decline.

Sturgeon were heavily fished during the 19th and 20th centuries. In addition to their eggs, sturgeon were valued for their flesh, which was eaten, and their skin, which was worked as leather for book-binding and clothing.

Atlantic sturgeon prefer hard, clean river bottom to spawn, Garman said. The James had vast granite outcroppings that suited their needs until the 1800s when the river was dredged to improve ship navigation, according to NOAA.

Dredging continues and the Port of Virginia expects more ship traffic, especially on the James as cargo is moved to Richmond by barge instead of trucks. The move, designed to reduce air pollution, could hurt the sturgeon population.

Commercial ships reported killing five sturgeon in the James in 2005, but the number is likely higher, the NOAA report said.

Sturgeon are also threatened by pollution, bycatch — when they are caught in nets set for other fish — and, possibly, the rise of blue catfish, which eat the same food and grow similar in size.

Uncertain future

Virginia outlawed commercial harvesting of sturgeon in 1974. A nationwide moratorium followed in 1998.