It is a long swim to Binghamton, N.Y., but the determined travelers are getting closer.
American shad -- that slightly oily, bony fish once as popular as the blue crab -- is making a comeback in a portion of its 500 miles of historic spawning ground along the Susquehanna River.
With the completion this spring of a $12 million fish lift -- the equivalent of an elevator -- at the Conowingo Dam, the number of the prized species to cross the 100-foot-tall structure doubled to 27,227 since the last spawning season.
"We call it 'the mother of all fish lifts,' " said Dr. Dileap Mathur, a senior fisheries scientist for RMC Environmental Services, who was hired by Philadelphia Electric Co. to work on the project. "It is the largest fish lift for American shad in this country."
The lift, along the Harford-Cecil county line, is capable of moving 750,000 shad and 5 million herring over the dam every season, but if need be, that capacity could double with some modifications, he said.
In a long, tumultuous journey, the shad, like the salmon, travels to the ocean from its birthplace in the upper freshwater reaches of rivers. About age 5, when they reach sexual maturity, they swim back to the stream of their birthplace, some traveling up the Susquehanna through Maryland and Pennsylvania to Binghamton and Cooperstown.
Once, the spring runs of shad and river herring, another popular bay species, so filled the Susquehanna that millions of pounds of fish were caught in commercial nets in a single three-month period.
But a decline in their populations began when four hydroelectric dams were built in the early 20th century. In the 1970s, a number of factors, including pollution and overfishing, conspired to reduce the number of shad even further. Maryland banned fishing for shad in 1980, after catches plummeted by 91 percent.
The completion of the lift ended a 30-year battle between Philadelphia Electric and Maryland and Pennsylvania. The two states wanted the company to remove the first and largest barrier for the fish.
The company, under an agreement with the two states, had begun operating a small fish lift in the early 1970s to see if a larger lift would dramatically increase the population. The first year, they caught 182 fish that had returned to the dam in a desperate struggle to spawn. By 1990, nearly 16,000 shad showed up at the dam for a two-hour ride by truck to a release point near Harrisburg.
And then this spring, with the completion of the permanent fish lift, that number nearly doubled again.
Equally important as the lift was a hatchery that raised baby shad and released thousands of them into the river to jump-start the revival of the Susquehanna River strain of shad. Because few fish were returning to the river to spawn, biologists knew they needed to imprint a new generation with the Susquehanna's scent.
So they took eggs from all over the East Coast to the hatchery. "We are creating a new Susquehanna strain," said Dick St. Pierre, Susquehanna River coordinator for the U.S. Fish and Wildlife Service.
Mr. St. Pierre said that it may be 30 or 40 years before the shad population is fully restored in the Susquehanna, the largest spawning river on the East Coast for shad. But state fisheries officials hope to open the river long before that to sports fishing, estimated to be worth $100 million to the state economies.
Three barriers to the shad migration remain: Holtwood, Safe Harbor and York Haven dams, all just above Conowingo in Pennsylvania. The utility companies that own those dams have agreed to negotiate the construction of lifts there. But state officials say they have been waiting months to see the first designs for those projects.
Peter M. Dunbar, Maryland's director of power plant and environmental review, said the state will be pushing for completion of the new fish lifts by 1995. "We think this is entirely feasible," he said.
Unless the three lifts are built soon, Dr. Dunbar said, the restoration program will stall. Currently, Philadelphia Electric trucks all the fish caught in the Conowingo lift two hours north, above the three other dams, then releases them.
But there are logistical limitations to the number of fish that can be trucked during the short spawning season, Dr. Dunbar said. "We think we are getting close to that limit."
This year, the utility made about 100 four-hour round trips during a two-month period.
Despite the long, frustrating restoration, officials said, recent strides have been gratifying. "We are very encouraged by the number of fish we see coming back to Conowingo," Mr. St. Pierre said. "We are very hopeful the river will be fully open to natural migrations within a decade."