American shad aren’t coming back in Va.

Something bright flashed near the surface of the murky James River. Will McCahill swung at it with a net and caught a piece of living history.

“Gentlemen, this is what it’s all about,“ said boating partner Chip Augustine, eyeing a handsome 18-inch fish with silvery, iridescent scales.

The prize was an American shad — probably the most important fish you’ve never seen. The shad, which migrates from the sea to freshwater rivers in the spring to spawn, once fed hungry Indians and settlers at winter’s end. It supported a huge Virginia fishing industry.

Thomas Jefferson caught shad. Legend has it that migrating shad saved George Washington’s troops from starvation at Valley Forge.

“This country was founded on American shad,“ said Augustine, with a nod toward a 2002 book by outdoor writer John McPhee, “The Founding Fish.“

How did Americans express their thanks to shad? We built dams that blocked them from spawning territory, polluted their waters, and caught way too many to obtain their roe and tasty-but-bony flesh.

The shad responded by nearly dying out.

McCahill and Augustine, employees of the state Department of Game and Inland Fisheries, were catching shad near the Mayo Bridge in Richmond early this month to check on their numbers.

The men are part of a $200,000-plus yearly effort to bring back the shad. But for reasons that mystify scientists, the shad aren’t coming back.

Commercial shad landings in Virginia dropped from 11.5 million pounds in 1897 to 550,000 pounds in 1993. The catch in the James, which topped 1 million pounds as recently as 1973, plummeted to 3,100 pounds in 1993.

The state made it illegal in 1994 to keep shad, ending centuries of shad fishing. Fishing off the coasts of Eastern states was banned in 2005.

“At one point, the American shad was the most important commercial finfish in the whole Chesapeake Bay,“ said Albert Spells, Virginia fisheries coordinator for the U.S. Fish and Wildlife Service. “Those numbers have collapsed.“

Shad also were important ecologically, providing meals for striped bass and other fish.

In the 1980s, Virginia decided to bring back the shad, and a major portion of that effort centered on the James. Workers blew or cut holes in three Richmond dams from 1989 to 1993.

In 1992, biologists began stocking millions of hatchery-raised baby shad upriver from the Bosher Dam just west of the Willey Bridge.

State officials estimated in 1993 that restoring shad in the river would pump about $5 million a year into Virginia’s economy, from the sales of fishing gear and other goods.

The final barrier facing migrating shad, the 10-foot-tall Bosher Dam, was breached in 1999 with the opening of a $1.5 million tunnel-like fish passage.

Opening the passage meant the shad could, for the first time since the dam was built in 1823, reclaim hundreds of miles of upstream spawning territory.

Hopes ran high. One state official said the passage marked “the final chapter of a success story.“

Results were promising at first. Nearly 800 shad swam through the passage in 2002. Experts figured thousands would move through by 2008.

Then, as Virginia Commonwealth University fish ecologist Greg Garman said, “the bottom dropped out.“

Fewer than 200 fish made it through the passage in 2003. About 50 made it last year.

The falling numbers indicate the James’ shad population has dropped even more, despite all the work to help the fish.

Each spring, the Virginia Institute of Marine Science monitors a sampling of shad caught in the James near Newport News. The program shows a decline since the monitoring began in 1998, and “2008 was the lowest year we’ve ever seen,“ VIMS marine scientist Brian Watkins said.

Experts reported similar declines at other East Coast rivers. The Atlantic States Marine Fisheries Commission, a regional regulatory agency, declared in 2007 that shad stocks were at all-time lows.

Scientists only can guess at the reason. Perhaps shad are getting caught accidentally at sea in nets set for other fish. Maybe global warming is causing the temperature-sensitive fish to get lost in migration.

Perhaps some predator, like blue catfish stocked in the James in the 1970s, is gobbling shad. Or maybe it’s a combination of factors.

Adding to the mystery is the strange case of the hickory shad, the American shad’s smaller cousin. So depleted in the early 1990s that some thought it would go extinct in the bay region, the hickory shad has rebounded so well that it draws thousands of anglers each spring to downtown Richmond.

“With no help from any management agency, no help from any biologist or any fish ladder or any of that, the hickory shad has come back like gangbusters,“ Garman said.

“That’s frustrating, because we can’t explain why” and can’t duplicate the formula to help the American shad.

Shad in the James spawn roughly from Hopewell to Richmond. Though some have moved through the Bosher passage, there is no evidence the fish have continued any distance into all that now-open spawning territory.

VCU researchers this spring are following 100 shad fitted with electronic transmitters the size of small toothpaste caps.

“We would like to see some fish that come to the base of the dam keep going, but so far we haven’t seen that,“ said Aaron Aunins, a graduate student helping conduct the study.

It’s possible that shad stocked in the James — the offspring of Pamunkey River shad — are not genetically programmed to swim far upriver, Garman said.

“It’s not an easy thing to say, but it may be the reason that not many American shad are moving beyond Bosher Dam is, there are just none of those fish left.“

In the past 20 years, about $9 million in federal, state, local and private money has been spent to bring back shad in the James. With shad numbers low and little to show for the construction of the passage, it’s easy to conclude that shad restoration in the James isn’t working.

But Garman said the work may be keeping shad from declining beyond the point of no return. “The fact that we still have American shad out there might be some evidence of the success of the program.“

On the James, McCahill and Augustine fished in a johnboat that periodically sent an electric charge into the water, stunning fish long enough to net them.

The men caught two shad in 45 minutes. They measured the fish, checked their health, and put them back.

Shad migrate through Richmond from late March to early June, with the peak running from late April to early May.

Alan Weaver, the game department’s fish-passage coordinator, said the number of shad in the James seems to have picked up this year. He hopes that’s a good sign.

“We’re still trying to give them a chance to make the comeback,“ Weaver said. “Hopefully, it’s not too late.“

Rex Springston is a staff writer for the Richmond Times-Dispatch