Fighting for the Ohio River watershed’s mussels: Experts are working to get to the bottom of their mysterious disappearances

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U.S. Forest Service Fisheries Research Biologist Wendell R. Haag holds a mussel shell. Like a tree, each ring on the shell indicates a year of growth. There are roughly 40 types of freshwater mussels in this stretch of the Licking River near Butler, Kentucky, one of the most diverse populations in the world. (Photo by Carrie Blackmore Smith/PublicSource)

“Will one of these fit?” Wendell R. Haag asks, holding out a couple pairs of well-worn creeking shoes he’s pulled from the back of his pickup. Haag is going to see an aquatic wonder, and even tall waterproof rubber boots are sure to fill with water in the sometimes knee-deep stretch of the Licking River.

Haag grew up near here, in Kentucky. He tells of his fascination with the bottom feeder he’s about to show. As a child, he began collecting opalescent nacre shells in shades of pink, purple and peach near his home.

The curious boy became a biologist for the U.S. Forest Service and is now a leading expert in the field of freshwater mussels, with a Presidential Early Career Award for Scientists and Engineers from President George W. Bush to show for it.

The Ohio River watershed includes the 981-mile main stem, from Pittsburgh to Cairo, Illinois, and also dozens of tributaries. Up and down each of these waterways, the mussel fauna changes; more of one species here, more of another there, different assortments determined by their immediate environments.

About 130 mussels species have been recorded in the Ohio River system — the most of any other river system on Earth except the Mississippi, because it includes the Ohio.

Haag goes to a specific spot on the Licking River to see an environment that supports more types of mussels than just about anywhere. Roughly 40 species have been recorded here, though several are no longer present. For scope, 16 species have been found in all of Europe.

“Very few people know any of this,” says Haag, standing in shorts, a raincoat and a Mississippi National Forest Stream Team ball cap. He adds that even fewer people understand the vital role mussels play in the environment.

This stretch of the Licking River near Butler, Kentucky, contains up to 40 species of freshwater mussels. (Photo by Carrie Blackmore Smith/PublicSource)

Mussels are good monitors of stream quality; they purify water, provide a structural habitat and food for other organisms and ease something known as nutrient overload, often caused by farm fertilizer run-off and water treatment practices. Mussels can naturally recycle and store some of these nutrients.

A lot of people don’t realize that humans are responsible for the extinction of at least 11 mussel species that once lived in the watershed and that about 70% are considered “imperiled,” meaning their rapid and continuous declines put them at risk of becoming extinct.

Haag is chasing after some answers behind the diminishing population.

“When I go out and look for mussels where they should be, they are disappearing,” Haag says, “time and time again.” Haag has a hypothesis as to why and a plan to test it. “Before I retire, I want to prove what is doing this.”

American progress hit mussels hard

Let’s just say Jeremy Tiemann is comfortable in a wetsuit. The aquatic ecologist has spent 22 years exploring freshwater habitats, many in the Ohio River watershed. At his job at the Illinois Natural History Survey, housed at the University of Illinois at Urbana-Champaign, his work informs how environmental regulations are set in the Prairie State for mussels and other freshwater fauna.

For all he’s seen, Tiemann is fairly confident that no other aquatic organisms have taken a bigger hit from American progress than the freshwater mollusks, mussels and snails.

“We completely changed the way the river behaves,” Tiemann says by phone from his office, and that’s not a good thing for these sensitive animals.

Tiemann did his master’s thesis on the impact of low head dams on stream ecosystems. While many species suffered setbacks and death from their construction, it specifically devastated many mussel species. It led to extinctions and substantially reduced population densities.

Why? First, the Ohio River was not naturally as deep as it is today. During a dry spell, people could walk across a lot of it. Locks and dams began to be constructed on the Ohio River around 1885 to raise the water level and allow for easier navigation, with the final dam in that system completed in 1929. In the 1950s, the dam system was modernized by the U.S. Army Corp of Engineers to improve flood protection and raise the water level for barges to transport materials like coal and salt.

Mussels typically like free-flowing water, Tiemann explains. Dams pool the water up behind them and create more pond- or lake-like qualities. Silt and debris built up, suffocating mussels. It also restricts fish migrations, which affects mussels because some use fish to complete their life cycles.

People also built dams on smaller tributaries, channelized streams and began discharging mine and industrial waste into the waters.

U.S. Forest Service Fisheries Research Biologist Wendell R. Haag demonstrates what part of the mussel to look for when searching for them in the water. Because they lodge themselves in the riverbed, the tip of its two shells are often all that’s visible. (Photo by Carrie Blackmore Smith/PublicSource)

So, while the Ohio River watershed has some of the greatest diversity of freshwater mussels anywhere on the planet, they’re in a precarious position, Tiemann says.

Pollution spills happen with some frequency and can kill them. They were harvested in some areas a few decades ago, when mussel shells were commonly used to make buttons. Mussels have also had to fight for their place against invasive species like the Zebra mussel, a fingernail-sized mollusk native to freshwaters in Eurasia. It is believed they arrived in North America in the 1980s on large ships from Europe, and they crowded out some native mussels early on.

“We are now starting to realize the true effects of the loss of mussels, and some of us want to improve their numbers and mitigate the problems that they face,” Tiemann says.

This includes reintroduction and rescue missions. Tiemann continues to monitor a 13-year project that involved moving populations of two endangered species of mussels away from a spot in the Allegheny River in Pennsylvania. The Hunter Station Bridge replacement was expected to kill the creatures. Tiemann and his team moved them to some streams in Illinois, while colleagues in the field moved them to six other states in the watershed.

Tiemann says many of the mussels are still living. But his team has yet to see evidence of reproduction, which is ultimately what they want to see. Juvenile mussels are extremely difficult to find so it could be another decade or more before they know if the mussels are reproducing.

Every day, he says, researchers learn more and more about these creatures.

“We have more people studying mussels and coming together than ever before,” Tiemann says, adding that the Freshwater Mollusk Conservation Society started with a handful of people in 1989. Now they are 500 strong, worldwide, with European and South American contingents. Founders now have students in leadership positions.

U.S. Forest Service Fisheries Research Biologist Wendell R. Haag talks about the freshwater mussels that live in this stretch of the Licking River near Butler, Kentucky. (Photo by Carrie Blackmore Smith/PublicSource)

Critical to the ecosystem, not your diet

Back on the Licking River, Haag has his head in a blue Lowe’s bucket, which he has modified with plexiglass to create a clear bottom.

Nah, you don’t want to eat these mussels, Haag says, pushing the bucket down and sweeping the river floor to find a live one.

Native Americans sometimes ate them but more often they would ground up the shells to temper pottery, Haag says. He’s eaten them and says, “They taste awful.” He’s used to first question being whether they’re edible, but he says there’s plenty of other reasons to want to keep mussels around.

Haag has found one in the water. The tip of its two shells is all that’s visible. It’s probably a big one, Haag says, carefully wiggling it out of the dirt and lifting the creature out of the water.

The common name for this one is a pink heelsplitter, he says, because they have an elongated wing that protrudes from the stream bottom and could split your foot. The nacre on the inside of their shells is a pinkish purple. The mussel ejects a thin stream of water and retracts a large slimy foot, which it uses to maneuver itself short distances in the riverbed to stay submerged in the stream.

Like with many trees, each ring on the shell of many native mussels represents one year of growth. Most live 20 to 50 years but some live past 100, Haag says.

It’s hard to imagine mussels suddenly disappearing from a place like this, but Haag has grown accustomed to seeing it happen. He’ll visit a place last documented to have a healthy population of mussels and instead find only dead shells mixed with old mussels past the reproductive stage. It’s only a matter of time before it becomes a shell graveyard.

In his years of research and considering other peer-reviewed work, Haag says he believes only two things could be the cause of the decline: either a disease that has not yet been identified or the Corbicula (Asian clam), an invasive species that has been thought to be harmless for decades.

He hopes an answer will help save these creatures whose benefits are just now being understood and, in some cases, harnessed by humans.

There is now a discussion about putting a monetary figure on mussels.

A paper on the topic was released in March 2018 in Hydrobiologia, an international journal of aquatic sciences. The authors called for more research on the economic, social and ecological value of mussels as well as “tools that will allow us to value mussel ecosystem services in a way that is understandable to both the public and to policy makers.”

Haag says it can’t hurt to determine a mussel’s worth.

Suddenly, he lets out a yip of excitement. It’s a plain pocketbook mussel doing something researchers only confirmed the function of in the 1990s.

The mussel pushes two flaps of her mantle out of her shell in a way that looks deceivingly like two minnows. She is trying to lure a fish by mimicking its prey. When a fish approaches and opens wide, the mussel will spray her larvae into the fish’s face, hoping to hit the gills. There, the baby mussels will attach themselves as parasites and feed off the blood of the fish. The general consensus, Haag says, is they are a relatively benign parasite. Damage to the fish is relatively rare.

It gets wilder. After they attach, they metamorphosize like a caterpillar into a butterfly. They change form — from a glochidia (parasitic microscopic larvae) to a bivalve with a shell.

At this stage, they fall off of the fish, land on the bottom of the stream floor and basically stay put. Studies show that pocketbooks only use bass as a host. “So, it’s integral that those fish are here, too,” Haag says.

‘Fight for these guys’

Biologist Janet Clayton is laying some knowledge on the next generation of mussel experts at the annual meeting of the Ohio River Valley Mollusk Group on a November morning.

Clayton has worked with mussels in West Virginia for three decades and has developed mussel surveying methods widely adopted in the field. She’s about to retire.

Today, gathered at the Thomas More University Biology Field Station on the Ohio River in California, Kentucky, she’s passing on specific advice. Her tips include the best brand of glue to adhere tags to a mussel’s shell and the way to sweep an area for mussels to count them properly.

“Now, it is your turn to fight for these guys,” Clayton tells the group, her voice catching. “Stay true to the resource.” The room, made up of roughly 40 biologists, ecologists, environmental consultants and scholars from six states, gives her a warm round of applause.

The morning talks wrap up and a discussion begins over the difficulty in getting the public to care about these unseen creatures. “How do we reach them?” one woman asks.

Professor Christopher Lorentz, director of Thomas More’s environmental science program, runs the facility, lab and conference space, which was originally built as a lock house in the Ohio’s first system of locks and dams. Lorentz, university staff and students study the river and its inhabitants there. Water is circulated from the river to raise and observe its fish, mussels and more.

U.S. Fish and Wildlife, state natural resource departments and nonprofits are working together to review impact of dams and cases where they could be removed. Organizations such as the Ohio River Foundation and The Nature Conservancy have been involved in dam removal and education about mussels. When a permit expires, the state or federal government generally reviews its impact on the environment to decide if it should be replaced or removed, Tiemann says.

It’s exciting, Lorentz says, to see the synergy between states and experts in the watershed. Scientists are learning more about mussels, “yet, there are some species that aren’t doing well in pristine areas.” And if we can’t figure that out, Lorentz says we can move them around, we can try to preserve them — but what will that do if the mysterious threat is still out there?

Haag says he thinks scientists need to look at the larger patterns and characteristics of the population decline and then focus in more closely on what could cause them. He continues to build on experiments he began in 2015 but fears one day he’ll arrive at this place — one of his favorite stretches of river — and find only dead mussels. But not today. Today we’ll see plenty of mussels, including the fanshell currently listed as endangered.

“Can you imagine?” Haag says. “It’s like walking into a forest that you know and there are no trees.” He walks on ahead with his bucket and talks of changing the outcome.

Carrie Blackmore Smith, a freelance journalist based in Cincinnati, Ohio, authored this story for PublicSource. She can be reached at carrieblackmoresmith@gmail.com.

This story was fact-checked by Sierra Smith.

Good River: Stories of the Ohio is a series about the environment, economy and culture of the Ohio River watershed, produced by seven nonprofit newsrooms. To see more, please visit ohiowatershed.org.

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