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Rare mussel species, nearly wiped out, gets rebirth in Virginia river

James spinymussels, recently reintroduced to the James River, were listed as an endangered species in Virginia in the 1980s. (Meghan Marchetti/Virginia Department of Wildlife Resources)
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Fifty years ago, a unique creature — known as the James spinymussel — lived in the thousands in the James River, which runs more than 300 miles from the Appalachian Mountains to the Chesapeake Bay.

But pollution and wastewater nearly wiped out the species, leading wildlife experts to grow the spinymussels at a hatchery outside of Richmond for more than a decade. A few months ago, they successfully reintroduced more than 2,000 of the mussels into the Virginia river that had long been their home.

“We’re just scratching the surface of recovering the populations we lost, but we believe the James spinymussels can make it and do well,” said Brian Watson, an aquatics resources biologist at the Virginia Department of Wildlife Resources. He helped lead the spinymussel work at the James River.

The work on boosting the spinymussels in the James River has been done in partnership with the U.S. Fish and Wildlife Service and the Virginia Department of Wildlife Resources.

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James spinymussels are one of about 80 species of freshwater mussels in Virginia, and experts say they’re a crucial part of maintaining healthy streams and rivers in the region. One mussel filters up to 15 gallons of water a day and works just like a water filter in a refrigerator, Watson said, helping prevent pollutants like nitrogen from flowing into waterways.

It’s an essential job, Watson said, that has earned spinymussels the nickname “the livers of the rivers.”

Spinymussels got their actual name because some of them have a pointy spike — sometimes two or three sticking off their shell — that Watson said is thought to help them “maintain their position in the stream bottom.”

If there are mussels in a freshwater river, he said, that’s a sign that the water quality is safe for humans to drink, swim in and fish from. Mussels help the ecosystem in other ways, too: Their beds make a good habitat for insects, and the mussels are a food source for muskrats and otters.

The spinymussels were listed as an endangered species in Virginia in the late-1980s. Conservation efforts for them started the following decade, as scientists tracked where their population decline had been hardest hit. They found that the mussels had once existed in abundance in the James River in the 1950s but had declined by the mid- to late-1960s, although some were found in tributaries of the river.

“We’d struggle to find five in an area,” Watson said, “where there had likely once been hundreds or even thousands.”

Reproducing is difficult for the mussels. They’re parasitic, so they have to get nutrients from the blood of a fish to become even a juvenile mussel. But catching a fish is no easy task, especially for a mussel with no feet or fins to swim.

To get on a fish, spinymussels basically spit their larvae into the water, and fish — mistaking it for a worm — often will come closer to it. The larvae then latches onto the gills of the fish, where it draws nutrients, grows and develops, staying attached for several weeks.

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Eventually, the spinymussel grows enough on its own that it drops off and, scientists hope, becomes a part of the adult population and reproduces. Spinymussels have a life span, on average, of about 20 years.

“They’re like a caterpillar in a way that’s developing into a butterfly,” Watson said. “If the larvae don’t get onto a fish, they just die.”

To help boost the spinymussel population in the James River, experts took some adult females from the water and re-created their life cycles at a hatchery. Once the female produced larvae, which can number in the thousands in one cycle, those larvae were placed in a tank with fish and observed to see whether they’d attach to the gills of the fish. It was a roughly two-year process before the spinymussels were mature enough as young adults to be put into the river.

This summer and fall, experts dove and carefully placed the spinymussels that had been harvested in the hatchery at six sites along the bottom of the river. Each mussel was marked with a tag so researchers can monitor and track their survival and reproduction.

Scientists said they eventually want to create at least 10 self-sustaining populations at the James River and its surrounding tributaries.

Joe Wood, a senior scientist at the Chesapeake Bay Foundation, said freshwater mussels like the spinymussels are important to the ecosystem of the bay and have been in “an impaired state for too long.”

The work to reintroduce spinymussels in the James River, Wood said, marks a “level of progress and a hope that they’ll survive and thrive.”