At River’s Bottom
This story originally appeared in the August 2016 issue of Wonderful West Virginia magazine.
At first, no one knew exactly what was happening, or why. But one fact was clear—lots of things were dying in Dunkard Creek.
Division of Natural Resources fisheries biologists Frank Jernejcic and Dave Wellman were at the Monongalia County stream almost every day during the September 2009 fish kill, surveying the damage. Lifeless fish lay dead on the shores and sandbars. The fish that remained alive thronged into pools of unspoiled water created by the confluence of Dunkard’s tributaries with the main waterway. “They couldn’t move into the main flow of the stream. They were stuck in these little areas,” says Jernejcic, who retired in late 2014.
The fish couldn’t swim upstream into those tributaries because the water level was too low. “They were frantic, like if someone sets off a bomb in the middle of a fairground and people try to make it to the exit,” Wellman says. Jernejcic remembers the last two he saw alive, a carp and a muskie. By the next time he visited the pool, those fish were died, too.
And then there were the white soft clumps of matter Wellman noticed floating downstream. “The first couple times I saw them, I thought it was clumps of toilet paper,” he says. But he realized it was much more worrisome than litter. After checking with fellow DNR biologist Janet Clayton, Wellman confirmed his hypothesis: those white clumps were actually mussels, floating free of their shells after they were killed by whatever unseen force wiped out the rest of Dunkard Creek’s aquatic life.
More than a week later, biologists finally figured out what caused the Dunkard Creek kill. A mine drainage pipe was dumping high levels of chlorides into the stream, creating brackish conditions that, when combined with low water levels and hot weather, created a perfect environment for Prymnesium parvum—more commonly known as “golden algae”—to grow. When the algae bloomed, it released deadly toxins that damaged the gills of fish and mussels, causing them to choke to death.
In the end, around 21,000 fish and 25,000 mussels died in the kill—every single living thing that called Dunkard Creek home. “Normally you have some fish alive. In this case, there were no fish left,” says Jernejcic, who saw hundreds of events like this in his career, and even served on the national committee that wrote the handbook on investigating fish kills.
Then, over the following weeks and months, something amazing began to happen. The algae dissipated as weather and water conditions shifted. Fish moved up from the Monongahela River and lower sections of Dunkard Creek. Within a year, biologists found 90 percent of fish species had returned to the stream. Within two years, 100 percent of species had returned, although the populations took a few more years to reach pre-kill levels. “It recovered very quickly,” Jernejcic says. “Two or three years later, I fished it and had one of the best smallmouth trips of my life.”
But not everything bounced back so easily. Years passed and the mussel population in Dunkard Creek remained nonexistent. Clayton, DNR’s foremost expert on mussels, says it can take centuries for mussel populations to recover after a catastrophic event because of the slow and cumbersome way these mollusks reproduce. “In a case like Dunkard Creek, it probably never would,” she says.
Luckily, Mother Nature has people like Clayton to help her along.
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DNR began its mussel restoration project in Dunkard Creek in 2011. Crews began collecting fully mature mussels during stream surveys and pulling others from streams where construction projects threatened the native mussel populations. They came from the Ohio River, Elk River, Tygart River, and several smaller streams including the unaffected north West Virginia fork of Dunkard Creek, and were planted directly in the substrate of Dunkard Creek.
Clayton and company also began growing their own mussels. In 2011, Clayton and her team moved their first brood stock into DNR’s facility in Belleville, Wood County. Mussels reproduce sexually—meaning both a male and female are required for the process—but since they can’t move to find a mate, male mussels release their sperm into the water, hoping a female somewhere downstream will catch it and use it to fertilize her eggs. This fertilization can take some time. For mussel species known as “long-term brooders,” this stage can last the entire winter.
Once the eggs have matured into larvae called “glochidia,” it’s time for another trip downstream. The mother mussel releases her glochidia into the water where, if they’re lucky, they will latch onto the gills of a passing fish. Or at least that’s how it works in the wild. At Belleville, Clayton’s crew placed the glochidia in a holding tank with small fish and then used a pump to aerate the water to keep the glochidia moving around, increasing their exposure to a potential host.
Mussels are picky about their hosts. While some species of mussels will work with entire groups of fish, other mussels require an exact subspecies before they’ll grab hold. Some, for example, only use skipjack herring. “There’s others that use catfish, there’s others that use darters,” Clayton says. “There are mussels that we still don’t know what their host is.”
For mussel species that require larger fish as hosts, Clayton had to take a more hands-on approach to inoculation. She collected the glochidia in a syringe, and then squirted it onto the gills of an appropriate host fish. She only used one side of the fish, however, to ensure the fish were not over-inoculated and had difficulty breathing.
Larvae develop into juvenile mussels during their time as parasites. When the mollusks have developed enough to survive on their own, juvenile mussels simply drop off their fish hosts and find a home on the bottom of the stream. In 2012, Clayton and her team released inoculated bluegill and drum fish at four different sites on Dunkard Creek, hoping the juveniles would settle into the streambed and begin to replenish the population. They also released fish in 2013 and 2014.
Things have not gone as Clayton hoped. “So far we’ve not seen any response,” she says. This difficulty did not come as a surprise, however—she knew from the beginning the odds were stacked against her project. The mussel reproductive process is long and finicky, and in the wild is largely a product of luck. Despite biologists’ efforts to circumvent luck, sometimes the natural order still prevails.
But that doesn’t mean Clayton has stopped trying. Mussels are far too important for that.
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Clayton first became interested in mussels back in 1989. She worked for DNR’s Office of Water Resources at the time, and was in her office one day when she overhead a new employee complaining just outside her door. Their boss was going to make him attend a class on mussels, and he did not want to go. Clayton jumped at the chance and volunteered to take his place. “Once I took the class, I was fascinated. They’re just amazing,” she says.
It wasn’t long before she moved to DNR’s office in Elkins where she got involved with a research tracking acid rain’s effects on fish. She still was working on mussel projects on the side, and over time her work became less about acid rain and more about mussels. When the research program wrapped up, her bosses asked Clayton developing a new mussel program for the agency.
Mussels are found all over the state—West Virginia is home to about 63 species, nine of which are on the U.S. Fish and Wildlife Service’s endangered species list. And despite their humble appearance, mussels are extremely important to their ecosystems. Because they bury themselves into the streambed, they help prevent erosion like trees on a hillside.
They are also nature’s sewage treatment plants. Mussels feed themselves by drawing water through their siphons and filtering out particulate matter and small organisms—a single mussel can filter five gallons of water a day. It’s not just food they are pulling from the water, however. “They also filter out the contaminants,” Clayton says. “They’re filtering everything out of the water. What they don’t use in their bodies, they’re binding into pseudofeces. Other critters can eat that. That’s less for that our water treatment plants have to deal with.”
But as helpful as they are to their ecosystems, mussels are also extremely vulnerable creatures. Most of the events that lead to mussel deaths are not big, dramatic happenings like Dunkard Creek. Clayton says mussel deaths are usually caused by a slow accumulation of sediments over time. “We have a lot of sediment impacts from road construction, from the oil and gas industry,” she says. Chlorides, like those found in fracking fluid or road salt, are especially dangerous. “That’s highly toxic to mussels, and even more toxic to juvenile mussels.”
They are also threatened by invasive species. Zebra mussels—a nickel-sized freshwater mollusk originally native to Russia—killed 25 percent of the native mussels in the Ohio River in 2000. The native mussels sucked the microscopic zebra mussel larvae through the water column while trying to feed. As the larvae develop, “they become this ball of zebra mussels on top of the native mussel,” Clayton says. The intruders use up all the food and oxygen in the water and starve out the native mussel.
By and large, there’s little anyone can do about these threats. The golden algae could come back, if the conditions are right. Clayton says industrial disasters seem to be getting more and more frequent. There’s nothing to prevent zebra mussels from entering the state’s waterways.
But she can try to repair what’s been broken. Although the Dunkard Creek restoration isn’t going very well at the moment, there have been other, more successful projects. When chemical spills on the Ohio River killed thousands of mussels, Clayton and her team went into the river to stock adult muscles. “Our main purpose was to get some mussels in there to help hold the substrate,” she says. But those mussels made way for more to follow. “The last time we surveyed it four years ago, we picked up an endangered species that has naturally recruited back into that site.”
It’s these kinds of victories that keep Clayton fighting her fight. Although it has been nearly 30 years since she attended that first class on mussels, her passion for the creatures remains as strong as ever. It might seem odd to some to devote so much energy—not to mention a career—to these often overlooked, not very attractive, bottom-feeding creatures. But for Clayton, it’s no mystery. “They’re quite important,” she says.