In recent years, the silvery shad that Native Americans used to teach European settlers how to fertilize crops, that helped feed George Washington’s Continental Army, and that provide food to eagles and otters, have started to disappear in alarming numbers. The disappearance has started talk of extinction, mostly because of four giant dams that block the Susquehanna River in Pennsylvania, where the fish were once abundant, according to the U.S. Fish and Wildlife Service.
Biologists say there’s one ray of hope for efforts to restore the Susquehanna’s shad — the looming expiration of operating licenses for two of the dams. Before granting a 30-year renewal, the Federal Energy Regulatory Commission requires the dam operators to study the environmental effects of their facilities. Based on the findings, the commission can require that conditions be greatly improved so that more shad can swim past them.
“It all depends on FERC,” said Mike Hendricks, a longtime fisheries biologist for the Pennsylvania Fish and Boat Commission, which operates a shad hatchery. It “needs to tell the dams to have 80 to 85 percent passage of the shad. If we can get [it] to do what needs to be done, we can get restoration. If we can’t, the game’s over.”
The commission confirmed in a statement that two dams, the Conowingo Hydroelectric Plant, built in 1928 and run by Exelon Power, and the York Haven Hydroelectric Dam, built in 1910 and run by York Haven Power, are in the “pre-filing state of the relicensing process,” meaning they must conduct environmental impact studies of the shad and other species affected by the plants.
A decision is a ways off, with release of the studies, critiques and public comments pending over the next three years.
Research shows that only 33 percent of shad get by the Conowingo dam and only 8 percent make it past York Haven, said Hendricks, citing figures provided by Pennsylvania.
Another dam, the Holtwood Hydroelectric Dam, owned by Pennsylvania Power & Light, passes 26 percent of shad. The Safe Harbor Hydroelectric Station, run by Constellation Energy, allows 72 percent of shad to pass.
Going with the flow
Water flow is like a road for shad. They swim against a current to head north. If the flow is too weak, they meander. If it’s too strong, they look for a milder passage, Hendricks said. The Conowingo dam often releases 85,000 cubic feet of water, far more than the 500 cubic feet of flow sought by shad.