A shad run that started unusually early and continued to deliver migratory fish into many Bay tributaries far into the spring resulted in what many biologists said was a solid 2012 spawning run.

That run, combined with what biologists hope will be good spawning success and new actions to curb shad bycatches in the ocean, could bolster shad populations that have floundered near-record low numbers both in the Bay and along the East Coast for more than a decade.

This year's unusually warm winter resulted in the earliest shad run ever reported on the James and Potomac rivers. Biologists from the Virginia Institute of Marine Science typically like to start their annual surveys before the first shad shows up.

This year, said Brian Watkins, a scientist with the VIMS Anadromous Fish Program, "we started sampling in the first week in February and there were already fish. We typically don't start until the last week in February."

Then, protracted cool weather in April and May helped to extend the spawning season.

In Virginia, the James River run appeared to be slightly better than the average since the VIMS survey began in 1998, while the Rappahannock index was the highest seen during that period, just edging out the previous peaks seen in 2003 and 2004. However, a downward trend continued in the York River.

In Maryland, biologists reported a strong run in the Patuxent River. And on the Potomac, an index of spawning adults was 22.6 per net, slightly better than the average of 21.6 since the survey started in 1995, and much better than the 11.7 reported last year, said Jim Cummins, a fisheries biologist with the Interstate Commission on the Potomac River Basin.

Not only were the fish present in good numbers, but the conditions for spawning were good as well, heightening the potential that this year's run could produce a good crop of young fish. "The river was clear and cool the whole time," Cummins said. "Based on what we were seeing, I think the spawn was good."

Not every place reported good news. Shad counted at the Conowingo Dam on the Susquehanna River were the third lowest since a multimillion-dollar fish elevator started lifting fish over the 100-foot-high structure in 1997. The 22,143 shad counted at Conowingo was well below the high mark of 193,574 seen in 2001 and only slightly better than the 20,571 seen last year, even though this year's run started earlier and lasted longer than usual.

Mike Hendricks, a fisheries biologist with the Pennsylvania Fish and Boat Commission, said part of the problem stemmed from operating troubles with the elevator. "They had a lot of maintenance issues, a lot of breakdowns early on," he said. "There were a number of days when they should have been operating and they weren't operating. That probably cut down their numbers."

Three of the four large hydroelectric dams on the river are up for relicensing in 2014, and state and federal fishery managers will seek improvements to fish passages at those facilities as part of the new licenses.

Biologists also reported good success in collecting eggs for hatchery production — it appeared likely that Baywide shad stocking efforts would exceed the Chesapeake Bay Program's 20 million goal, an achievement that has become less common in recent years.

Maryland was on track to stock nearly 4.2 million shad larvae and juvenile fish into the Choptank River, and another 100,000 small fish in the Tuckahoe, a Choptank tributary. That far exceeded its 2.75 million target, said Chuck Stence, a fisheries biologist with the Maryland Department of Natural Resrouces. "That is pretty amazing," he said. "The really good spawning run on the Potomac made it easy for us to get eggs."

Virginia stocked 5.35 million larvae in the James, and nearly 6 million in the Rappahannock. Pennsylvania stocked more than 3.4 million in the Susquehanna.

Biologists said survival conditions for the larvae seemed good — but, "If we get into a dry summer, it may change the picture," Cummins said.

Shad are an anadromous species and spend most of their lives in the ocean. They begin returning to their native river to spawn when they mature at 4–5 years of age. Their spring spawning runs once filled Bay tributaries with numbers unimaginable today: Colonial settlers reported they could not drive wagons across streams without crushing migrating fish. In recent decades, populations have plummeted as a result of overfishing, construction of dams that block access to historic spawning areas, habitat degradation, water quality and other factors. Shad populations along the coast are considered to be at or near an all-time low.

Because of their links to the watershed and the Bay, restoration of shad and river herring are priorities of the state-federal Chesapeake Bay Program. Shad have been the target of intense stocking efforts each spring for decades. Despite those efforts, shad have shown little evidence of a significant rebound over past decades. Increasingly, some biologists and conservation groups have pointed to fishing fleets in federal waters — those more than 3 miles offshore — as a possible explanation. Anecdotal evidence suggests that potentially significant numbers of shad and river herring are caught as bycatch in some fisheries operating in those waters.

In June, the Mid-Atlantic Council, which regulates catches in federal waters, called for requiring onboard observers on vessels fishing in waters where catches of shad and river herring are likely. The council also called for eventually setting a cap on any catches of those fish.

It's unlikely that regulations implementing those programs would be in place before 2014, but Teresa Labriola, senior associate of the Pew Environmental Group's Northeast Forage Fish Campaign, praised the council for showing "strong support for protecting river herring and shad."

"These are the most significant and immediate steps you can take to identify, quantify and ultimately reduce bycatch of these significant species," she said.

The New England Council was also moving to rein in bycatch in federal waters off New England.