Dammed, drugged, poisoned: River fish species struggle to survive

Bass Smallmouth
Smallmouth bass are sensitive to pollution, making their health a key indicator of the health of the watershed.

YORK, Pa. — Brian Shumaker caught his first fish when he was maybe 8 years old.

He grew up in New Cumberland, Pennsylvania, two blocks away from the Susquehanna River _ his family pretty much living outdoors. Both of his grandfathers fished and hunted, as did his father and all of his uncles.

He remembers the first catch, hooking a feisty bluegill on a farm pond.

“I loved it,” Shumaker, now 55, said. “I got a big kick out of it.”

He was hooked, so to speak.

He pretty much grew up on the river, fishing for smallmouth bass and catfish, learning as almost a reflex how to read the water and where to look for fish. “The river was my playground growing up,” he said.

He began working on occasion for a fishing guide, taking anglers out and showing them the ropes. In 1993, he started his own guide business, Susquehanna River Guides, specializing in fly fishing the river for smallmouth bass. His clients come from all over the country, and the world, some from as far away as Europe, for the opportunity to fish what had been considered a world-class smallmouth bass fishery.

“It’s still in the top 10,” Shumaker said. “There are still big fish out there, but not as many as there used to be. Something’s changed.”

What’s changed is that civilization has caught up with the smallmouth bass.

The fish are among the species that call the river their home – along with American shad and eel – that have been most affected by human activity. The species are very different, and the challenges they face are varied, but one thing is certain: their numbers are not what they used to be, and that is a reflection of the health of the watershed.

Shad and eel – species that migrate to spawn – are hampered by the four large hydroelectric dams on the lower section of the river, from the Conowingo near the river’s mouth in the south, to Holtwood, Safe Harbor and York Haven dam, respectively, to the north. The dams, in addition to causing problems with sediment, impede the migration of the shad and eel, migration that is essential for the fish to propagate.

Smallmouth bass, though, are more indicative of water quality, often referred to as “the canary in the coal mine” because of its sensitivity to pollution and disease – those pathologies often pointing to pathologies in the watershed itself.

These three species illustrate the challenges facing the watershed and the importance of mitigating human impact on the waterways.

Shad: They once carpeted the surface of the river

American shad were important fish in the lives of Native Americans and early European settlers.

There was a time when the shad was among the primary sources of protein for Native Americans. Legend has it that the shad were so plentiful in the Susquehanna that it was like a carpet of fish on the water’s surface. Shad are schooling fish, and some schools back when shad were plentiful could run into the thousands of fish.

“It was said that you could trade a barrel of shad and still have a barrel of fish for next winter’s food supply,” said Josh Tryninewski, a biologist with the Pennsylvania Fish and Boat Commission. “They were a very important food fish, and a very important fish for the economy of the river.”

To understand how shad are impacted by human activity, you have to understand their life cycle. Shad spend their adult lives in the Atlantic Ocean. When it comes time to spawn, according to biologists, they swim into the Chesapeake Bay and into the freshwater of the Susquehanna to reproduce. Juvenile shad remain in the freshwater until they mature and then return to the sea.

Now, it doesn’t take much imagination to figure out how the construction of large hydroelectric dams on the river can cause an impediment to adult shad as they look to produce little shad.

The first was the Holtwood dam, south of the area in the river now called Lake Aldred, built between 1905 and 1910. At the time, it wasn’t known what kind of impact the dam would have on wildlife and the health of the river.

Eels: Uber drivers for mussel larvae

Eels are considered the taxi cabs of the Susquehanna, or as Tryninewski updated it, “Uber drivers.”

How eels earned that nickname has to do with its symbiotic relationship with freshwater mussels, a vital, and imperiled, species.

The U.S. Fish and Wildlife Service describes the relationship between the two species as “complex.”

“Mussels lure in fish by displaying realistic copycats of mayflies, crayfish or minnows that are really flaps of tissue made by the mussel,” Julie Devers, a fish biologist for the Fish and Wildlife Service, wrote in 2017. “The fish thinks this lure looks like food, but when it takes a bite, the mussel shoots out a stream of tiny larvae that attach to, or `infect,’ the fish’s gills. Tiny mussel larvae hitch a ride on the gills of fish until they mature into baby mussels.”

And that is how freshwater mussels are distributed throughout the river’s watershed.

But, Devers wrote, “If the right fish isn’t present in the stream to serve as a temporary host for the larvae, the mussels cannot reproduce, and populations die off. The most common freshwater mussel in the Susquehanna River, eastern elliptio, needs the American eel.”

And, as with shad, the dams on the river, most notably the Conowingo, have endangered eels. Eels have kind of a flip-side life cycle from shad, spawning in the ocean and swimming into freshwater watersheds to live their adult lives. They can live in the river and its tributaries for up to 20 years before returning to the Sargasso Sea in the north Atlantic to spawn.

Devers wrote: “Eels are amazing at getting where they want to go, sometimes climbing up sheer walls. However, the 90-foot-high Conowingo Dam, near the mouth of the Susquehanna River, is insurmountable. Dams in the Susquehanna River started blocking eels from swimming upstream around 90 years ago.

“When eels stopped swimming up the Susquehanna River, the eastern elliptio mussels in the river and its tributaries stopped making babies. Scientists estimate that most of the remaining eastern elliptio mussels in the watershed are over 75 years old.”

Smallmouth bass afflicted with lesions, intersex organs

Before 1869, smallmouth bass did not exist in the Susquehanna watershed. Smallmouth – or smallies or bronzebacks, as they are known – are native to the upper and middle Mississippi River basin, the St. Lawrence River and Great Lakes up to the Hudson Bay, where they were prized as a game fish, legendary among anglers for putting up a fight.

That year, a group of sportsmen sought to introduce smallmouth bass to the Susquehanna watershed and traveled to a commercial fishery in Havre de Grace, Maryland., to purchase some of the fish and transplant them into the river, the Fish and Boat Commission’s Smith said. The initial population of smallies in the Susquehanna was 25 fish, purchased for $25, $496 in today’s money.

Within three years, Smith said, they were abundant. “They just took off, like any invasive species does,” he said.

Smallmouth, technically speaking, are not considered invasive. Rather, they are considered an exotic species, the difference being, according to the Chesapeake Bay Foundation, invasive species kill off native species through predation or by hogging limited resources for native fish. Exotic species exist in harmony within the watershed.

So why care about smallmouth bass? “Why should we try to save them?” the Chesapeake Bay Foundation’s website asks.

For one thing, according to the foundation, “smallmouth bass comprise a $630 million industry across the Bay watershed states.” The Susquehanna had been considered among the nation’s top five rivers for smallmouth fishing, attracting anglers from all over the country to fish for trophy-sized bronzebacks.

For another, smallmouth bass are sensitive to pollution, making their health a key indicator of the health of the watershed.

The foundation’s entry on smallmouth bass says, “High levels of nitrogen and phosphorus pollution, rising water temperatures, and chemical contaminants may have combined to weaken the immune systems of smallmouth bass and make them more susceptible to naturally occurring bacteria, viruses, and parasites.”

Over the decades, the smallmouth population in the Susquehanna watershed has fluctuated, but in 2005, they nearly disappeared from the Susquehanna, its west branch and the Juniata River. “Fish were seen swimming weakly near the surface with noticeable white lesions, sores, and eroded fins and some were dead,” Smith wrote in a Fish and Boat Commission report published in 2010.

Shumaker, the fishing guide, recalled looking out on the water “and just seeing dead fish.”

“I had no clue what was going on,” Shumaker said. “The fish commission had no answers. Nobody knew what was going on.”

It wasn’t until 2018 when researchers at Michigan State University figured out what caused the fish to get sick and die – a largemouth bass virus. Normally, biologists said, the virus doesn’t afflict smallmouth bass. But higher water temperatures – thought to be the result of climate change – and pollution degrading the fishes’ immune systems made the virus deadly to smallies.

In a 2013 report published by the bay foundation, research fisheries biologists with the U.S. Geological Survey wrote that smallmouth bass “were under siege by a `perfect storm’ of pollution, chemicals, and climate.”

The fish also have developed mutations referred to as “intersex.” Scientists report finding eggs from female fish in the reproductive glands of males. The mutation is believed to be caused by pharmaceuticals entering the watershed. Smith explained that remnants of the chemical compounds from some pharmaceuticals pass through humans into wastewater, compounds that cannot be removed from the water at sewage treatment plants.

Other pollution, such as high levels of nitrogen and phosphorus from farm runoff and chemicals from herbicides, cosmetics, detergents and hormones from human and animal waste, also threaten the health of smallmouth bass.

Smallmouth bass have come back, biologists and anglers report, but not quite in the same numbers as before the virus struck. They are still at risk.

“Where it goes from here, I don’t know,” Shumaker said.

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