Long slog ahead for new attempt to move shad past Conowingo, other dams
Steep drop-off in fish making it to spawning grounds puzzles scientists
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Leon Senft remembers a time when he and other fishermen lined the shore of the Susquehanna River below the Conowingo Dam and hooked American shad almost as fast as they could cast their lines in the churning water.
“We really had a bonanza there for a while,” recalled Senft, 85, who’s been angling for the big migratory fish longer than most people are alive. “It was not unusual to catch 50–100 a day. My personal best was 175.”
That catch-and-release heyday for Senft was maybe 20 years ago, when American shad appeared to be on the rebound from a severe decline in their springtime spawning runs. Optimism abounded, as a big new fishlift hoisted more and more of them over the 94-foot dam on their way upriver to reproduce.
But the rebound went off the rails. Although the number of American shad getting a lift over Conowingo rose steadily for a decade, it then dropped and kept dropping.
Now, after years of study and negotiations, the U.S. Fish and Wildlife Service and Exelon Corp., Conowingo’s owner, have come up with a new plan for rebuilding the Susquehanna’s runs of American shad and river herring — related species that are even more depleted. In a press release announcing the deal in April, a federal wildlife official called it “a victory for everyone who lives or recreates on the Susquehanna River and the Chesapeake Bay.”
But those close to the situation are still cautious. Given the discouraging track record so far, they say, bringing these fish back will take a sustained effort for decades — if it can be done at all.
“I was around when we did this last time, 25 years ago,” said Bill Goldsborough, senior fisheries scientist for the Chesapeake Bay Foundation. “We thought that was going to do a lot more than it did.”
In 1991, hopes ran high for finally restoring what was once one of the Chesapeake Bay’s most valuable fisheries. That spring, a new $12 million fish lift — heralded as the largest of its kind in the nation — began hoisting American shad and river herring over Conowingo to get them closer to suitable spawning grounds in Pennsylvania and New York.
Maryland’s Department of Natural Resources secretary called the aquatic elevator “a phenomenal achievement” in a century-long struggle to restore the huge shad runs that once roiled the waters of the Bay’s largest tributary.
For about a decade, that seemed the case. Shad numbers passing the dam on their way upriver steadily grew. In 2001, nearly 200,000 took the lift, as did nearly 300,000 of their smaller, similarly migratory cousins — alewife and blueback herring — which also had been caught in abundance at one time.
That proved to be the high-water mark of the restoration effort, though. The numbers of shad and river herring at Conowingo fell sharply the next year and have trended downward since. Last year saw a new low of just 8,341 shad using the lift near Darlington, MD, and only 13 river herring. A paltry 43 shad made it past all four dams blocking the lower Susquehanna. This year’s run rebounded slightly, with 14,276 American shad passed upriver from Conowingo. That's the most since 2012, but less than 10 percent of what the lift handled in either 2000 or 2001. A paltry 23 herring got a lift this year.
A forgotten fishery
Shad could use a public relations agent today, as few non-anglers know much about them. But for centuries, they were a springtime staple in the Bay region and all along the East Coast. Every year, as the weather warmed, they surged inland from the Atlantic, thronging rivers from Maine to Florida.
Bay region residents — first native Americans, then European settlers — marked the end of winter by feasting on the bony but succulent fish — called “poor man’s salmon” by some — and its roe, or eggs. George Washington operated a shad fishery on the Potomac River, and some farmers used them to fertilize their crops, the catch was so abundant. Fishermen strung nets across rivers to intercept the spawning runs and hauled tons of them ashore.
The cornucopia began to fade under such extreme fishing pressure, along with the loss of spawning grounds to a proliferation of dam construction that powered the young nation’s growing economy. The Chesapeake region’s annual harvest dwindled from 17.5 million pounds at the beginning of the 20th century to less than 2 million pounds by the 1970s, according to the USF&WS.
By 1980, Maryland’s shad harvest had sunk to 24,000 pounds, and the state imposed a moratorium. Virginia followed in 1993. Though shad are still harvested from a few East Coast rivers, their coastwide populations are at or near all-time lows. Only a dwindling number of people in the Bay region even know what they taste like, and fewer still know the trick to preparing or cooking them. Shad, Goldsborough said, have become a “forgotten fishery.”
Their decline has come in spite of considerable money and effort spent since the 1950s to restock them and help them get past the barriers to their historic spawning grounds. In the Bay alone, about 24,500 miles of river and stream have been reopened by installing ladders and lifts — or more commonly lately, removing dams, according to Mary Andrews, an environmental engineer with the National Oceanic and Atmospheric Administration. Shad runs have come back on the Potomac River, but Baywide abundance remains well below the restoration goal.
Nowhere is the challenge greater than on the Susquehanna, where four large hydroelectric dams within the first 55 miles of the river stand between the fish and suitable spawning areas.
The Susquehanna once had more shad and herring spawning habitat than any river on the U.S. East Coast. But when the Holtwood dam was completed just north of the Pennsylvania state line in 1910, shad fisheries in that state disappeared, and the Maryland harvest fell by two-thirds. When Conowingo was built on the south side of the state line in 1928–29, it cut the fish off from all but 10 miles of the river that they had once ascended all the way to Coopertown, NY, to lay their eggs.
Since the ’70s, hatcheries in Maryland and Pennsylvania have stocked the Susquehanna with more than 200 million tiny shad fry and fingerlings, produced from adults caught at Conowingo and in other rivers. And after the Conowingo lift was completed in 1991, lifts and a fishway were built at three upriver dams over the next decade.
While that seemed to help for a while, numbers have been dwindling there for more than a decade.
Every spring, biologists with the Maryland DNR conduct a survey for American shad in the Susquehanna below Conowingo. Their most recent estimate: somewhere between 140,000 and 300,000 — a third or less than what had been tallied there 15 years ago, when the number of fish passed by the lift was at its peak. The number swimming aboard the lift has fallen off even more sharply.
“We’re looking at numbers lower than what they passed before they put in the fishlift,” said Genine Lipkey, a biologist with the DNR who coordinates the state’s monitoring for shad and river herring.
After years of studies, experts say they have clues but no clear, agreed-upon explanation for the decline.
“Why they dropped off is a mystery,” said Sean McDermott, hydropower program coordinator for the National Marine Fisheries Service. “But there’s a lot of things that haven’t helped.”
McDermott suggested that the “east” fish lift built in the middle of the river hadn’t operated as designed.
But Kim Long, an aquatic biologist with Exelon Generation, a subsidiary of Exelon Corp., said a review of a decade’s worth of records turned up no significant differences in how the lift or the dam were operated.
Long noted that the drop-off began soon after the cessation of a “trap-and-transport” program, which hauled shad by truck from Conowingo and released them in better spawning habitat beyond all four dams. About 33,000 fish a year hitched a ride upriver that way, the Exelon biologist said. The utility-funded fish taxi service ended in 2000 after more than a decade and a half of operation, once lifts and a ramplike fishway had been built at all four dams, theoretically giving fish a path to suitable spawning areas.
A new agreement
The 46-page agreement signed in April commits Exelon to resuming the trucking operation, which biologists consider a stopgap remedy while they figure out how to make the fish passage facilities work better.
“It’s not meant to be a long-term solution to the problem, but to get fish up to the spawning grounds faster,” said Sheila Eyler, project leader for the restoration effort in the USF&WS’ mid-Atlantic office. Using both its small west fishlift and the big one on the other side of the river, Exelon will trap and haul up to 100,000 shad a year upstream, and an equal number of river herring.
The agreement also requires upgrades to Conowingo’s main fishlift, and to make adjustments in dam operations and in the river below the dam, to try to better attract American shad and river herring. Studies indicate the lift has been picking up as few as 25 percent of the American shad showing up at the base of the dam.
There are still plenty of shad taking the lift — just the wrong kind. A steady stream of gizzard shad flash past the viewing window atop the dam, where fish raised from the turbulent water below are released into the comparatively calm pond upriver.
Gizzard shad are darker and rounder than their American shad relatives, but they’re not considered fit to eat, earning the nickname “mud shad” among anglers. Though native to the region, they historically were less abundant, scientist say. But their population has surged since the 1970s, for reasons not altogether clear.
Last year, while only 8,300 American shad took the lift, 743,000 gizzard shad jammed aboard.
“We never anticipated in the late 1980s that we were going to have this big push of gizzard shad,” Eyler said.
With so many other fish — including striped bass, catfish and others — crowding into the elevator, some think that American shad may be getting left behind.
“The American shad are difficult to pass because of their behavior,” said McDermott, “so when you have a congested situation, the conventional wisdom is that the American shad will just back out, they’ll drop downstream.”
To remedy that, the new agreement calls for Exelon to replace the lift hopper in use since 1991, nearly doubling the amount of water — and fish — it can hold, from 3,300 gallons to 6,500 gallons. The company will also add a second hopper of the same size, quadrupling the lift’s capacity.
Federal wildlife officials had initially wanted Exelon to build a second elevator, but the agreement puts that off for 25 years, in part to give the company time to make other adjustments in the design and operations of its hydroelectric facility to attract more fish.
As it is now, some think the amount of water surging through the power-generating turbines drowns out the flow to the lift, making it hard for shad and herring to find the lift’s opening. The flow of water coming from the lift is to be increased, to give the fish a stronger homing signal.
Eyler said federal officials were willing to delay building a second lift — which Exelon had argued would be costly and ineffective — because they saw the trap-and-transport program as an insurance policy if the upgrades to the existing lift didn’t produce the desired results.
Plus, the trucking operation would get shad and herring all the way to their spawning grounds while upgrades are being completed to the upriver fish passage facilities. Only the lift at Safe Harbor — located two dams upstream — does well, passing nearly 85 percent of the fish that make it that far.
“Unfortunately, at Safe Harbor, we don’t have a lot of information about why it works so well,” Eyler said. “We generally study things that don’t work.” Officials hope to get the dam’s operator to do those studies as part of its relicensing in 2030, which may help in making adjustments to lifts at Conowingo and Holtwood. Operators of York Haven dam — the last barrier encountered by migrating fish — have already agreed to replace the poorly functioning fishway there. It only manages to pass about 14 percent of the spawning fish that get past Safe Harbor. Some years, it passes none at all.
Beyond that, officials say they’re not sure what more can be done. There was once more hatchery stocking, Eyler noted, but ramping that up again isn’t feasible. Shad runs have been so poor in many other nearby rivers, she pointed out, there aren’t as many places from which to take broodstock for hatchery use.
Given the poor track record of fish passage on the Susquehanna, some scientists argue that the only way to bring shad and herring runs back is to take dams out.
“I think we need to start thinking more creatively about this,” said Karin Limburg, a professor of environmental and forest biology at the State University of New York. While welcoming the move to resume trucking fish upriver, she said, “it’s not going to work in the long run. Sooner or later, people are going to have to stop kicking that can down the road.”
Limburg questioned how essential Conowingo’s power generation is to the mid-Atlantic region’s electric grid, noting that while its turbines are capable of generating up to 572 megawatts, they usually operate well below that level. Dam removals on other East Coast rivers have resulted in quick, impressive comebacks of fish, she said, and alternatives have been found to the hydropower that’s lost.
“There’s a lot of data out there to establish that dam removal is the preferred solution for increasing population size and restoring fisheries,” acknowledged NOAA’s Andrews. For that reason, federal agencies have shifted in the past decade or so away from promoting lifts and fishways.
Eyler said it’s customary to weigh dam removal in relicensing discussions, but in Conowingo’s case, it likely didn’t get serious consideration. The dam’s 14-mile long pond provides water for at least two other power plants upriver, and serves as a backup drinking water source for the city of Baltimore. Moreover, taking out the dam could stir up the massive buildup of nutrient-laden sediment, washing it downriver and adding to the Bay’s water quality problems.
Fishlifts and ladders can and do work in some cases, said McDermott of the marine fisheries service.
“Look at the Columbia River,” he said, on the West Coast. “Shad is an introduced nonnative fish, and they’re passing hundreds of thousands” via ladders over large hydroelectric dams. “So it can be done.”
But he acknowledged that while there are a few examples of successful fish passage on rivers with multiple dams, “the reality is it’s very difficult.” On each successive dam upriver, the numbers of fish showing up and using lifts or ladders drops off in a big way, again for reasons that aren’t readily apparent.
“We still have a lot to learn about this river,” said Tara Moberg, a freshwater scientist with The Nature Conservancy in Harrisburg.
Problems beyond the Bay
Some think the problem isn’t necessarily with the lifts — or at least not completely. They suspect shad numbers have been depressed coastwide by continuing fishing pressure in the Atlantic Ocean, where they spend up to five years before returning to spawn in the river where they hatched.
Offshore fishing fleets going after Atlantic herring, squid, mackerel and butterfish may be unintentionally netting shad and river herring that mingle with those targeted species. Despite bycatch caps and reporting requirements imposed by councils that regulate fishing in waters offshore under federal jurisdiction, fisheries officials and conservationists say they’re not sure what’s happening.
“We can try to put as many eyes as we can on these fish as they’re coming back to their spawning grounds in state rivers, but without being able to quantify that catch in federal zones, it’s really difficult,” said Kirby Rootes-Murdy, with the Atlantic States Marine Fisheries Commission, which coordinates state regulation of nearshore fisheries.
“That continues to be a problem,’’ said the Bay Foundation’s Goldsborough. He said the catch cap for shad set by the Mid-Atlantic Fishery Management Council was “pretty liberal,” and he suggested it was time to consider stricter measures.
About the only thing that’s clear is that it likely will be several years before it’s possible to tell if any of the new restoration efforts are paying off on the Susquehanna. Exelon doesn’t have to do anything until it receives a new 50-year operating license from the Federal Energy Regulatory Commission, and that’s still maybe two years away. And once more shad actually get to their spawning grounds — whether under their own power or by hitching a ride — it will take up to five years for their offspring to return.
Still, although the agreement will last half a century, Eyler pointed out that it calls for regular re-evaluation and adjustments if goals aren’t reached — something absent in the last agreement.
“I’m just hoping to see shad come back,” said Eyler. At 41, she figures she’s halfway through her career with the wildlife service.
The ultimate goal is to get 2 million shad and 5 million river herring past all four dams, but given the attrition in numbers of fish passing each dam, as many as 5 million shad and 12 million herring may have to make it to Conowingo’s tailrace. Shad have a long way to go, and herring even farther.
“I’m sure they’ll keep working on it, and I hope they find a solution,” said angler Leon Senft, former president of the now-defunct Susquehanna Shad Club, whose membership has faded away like the fish. “Personally, I don’t think I’m going to be here to see it…Of course, nothing ventured, nothing gained.”
- Category: Fisheries
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