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Endangered mussels seem to thrive in new home in Cassadaga Creek

FALCONER – Waist deep in murky water, biologists Anne Rothrock and Scott Cornett blindly scoured Cassadaga Creek looking for clubshell mussels.

Their search for the endangered mussel species would have been almost impossible just a couple years ago. Only three were known to exist in New York State.

On Thursday, Rothrock and Cornett plucked dozens from the creek bed.

Nearly all of the clubshells they found were marked with an electronic tag and planted in Cassadaga Creek over the last two years by state Department of Environmental Conservation biologists as part of a cooperative restoration effort by New York, Pennsylvania and the U.S. Fish & Wildlife Service.

“It shows it’s suitable habitat for the clubshell,” said Justin Brewer, a DEC fisheries biologist who led the creek survey. “The signs are looking good for the future.”

That's good, the biologists say, because the mussel – one of 18 species found in Cassadaga Creek – plays a vital role in filtering contaminants from the creek, cleaning the water and keeping its ecosystem in balance.

Based on the survey, the one-year survival rate of the stocked clubshells could be between 50 percent and 75 percent, Brewer said.

Keep in mind, survival estimates of this type are more of an indicator than an exact science, he said.

Predators and the changing natural conditions can vary from year to year.

A total of 175 mussels tagged with passive integrated transponders were collected, and 129 of them were alive.  But until the biologists fully analyze the data, they're not calculating a survival rate yet.

The biologists also found untagged mussels while digging at one of the sites, "which is another indication that the mussels seem to be doing well at the sites," Brewer said.

A Pennsylvania environmental agency supplied about 1,500 clubshell mussels to the DEC last year to jump-start the restoration after a successful pilot project in 2015.

A pair of bridge construction projects – separated by 50 miles and a state border – helped launch the restoration effort.

When an abundance of clubshell mussels were found at the site of a bridge construction project at the Allegheny River near Tionesta, Pa., they needed a home.

Cassadaga Creek in Falconer was a prime spot.

That’s where The Nature Conservancy had found what were the only three known clubshell mussels in New York State, a fact that became part of an environmental analysis for another bridge reconstruction project – on East Ross Mills Road over Cassadaga Creek.

“Everything was coming together at the right time,” said Michael Clancy, a regional DEC fisheries manager.

One of every 10 mussels from Pennsylvania was equipped with a rice-sized “PIT-tag” attached to the outside of the mussel shell with a strong epoxy.

The rest were marked with emerald green glitter.

The mussels were divided equally and “planted” in three sites along about a half-mile stretch of the creek bed northwest of East Ross Mills Road.

Using a wand that looks like a metal detector, the DEC biologists surveyed the stream Thursday to locate those mussels and gauge the species’ ability to survive.

When the wand passed over a tagged mussel,  it emitted a series of quick beeps and a numeric code on an LED screen.

That’s when biologists like Rothrock and Cornett went to work.

They reached down to the bottom of the creek and pulled up handfuls of small rocks, silt and shells.

Sometimes it took only one or two tries to find a clubshell mussel. Other times it took a dozen or more attempts.

DEC’s Anne Rothrock shows a live tagged clubshell mussel she found in the Cassadaga Creek near Falconer. (Mark Mulville/Buffalo News)

When they found one, they’d compare the tiny number attached to the mussel with the one on the wand and log it.

Surviving mussels went into one bag. Deceased mussels into another.

At the end of the day, they returned the surviving mussels to the creek.

Officials found preliminary data from Thursday’s survey encouraging.

“Overall, it went really well,” Brewer said. “We got well over 50 percent survival based on the PIT-tags.”

Clubshell mussel populations dwindled because of degraded water quality and habitat loss from development.

Re-establishing them from almost nothing will be challenging.

They are prey for various wildlife species, including raccoons, muskrats and mink. The evidence was rife along the shoreline of Cassadaga Creek. Dozens of mussel shells were spread across the banks of the creek, including a nifty little pile stashed just outside of the hole of some creek-side predator.

Some of the shells were from mussels marked by the DEC. Others were different mussel species.

Of the 50 freshwater mussel species identified statewide, 35 are in the Allegheny River basin with the most – 18 of them – in Cassadaga Creek.

“It has the most diverse species of mussels and darter species in the state,” Clancy said.

The Cassadaga Lakes and Bear Lake in northern Chautauqua County feed Cassadaga Creek. The creek drifts south into Conewango Creek near Frewsburg, flows into the Allegheny River in Warren, Pa., then to Pittsburgh where it meets the Ohio River and finally into the Mississippi River at Cairo, Ill.

The clubshell mussel is a native species to that system.

“We’re essentially restoring a native population,” Brewer said.

What happens next?

Brewer said similar assessments are scheduled at the three- and five-year marks – in 2019 and 2021 – to evaluate progress.

If all goes right, the mussels will reproduce on their own and re-establish populations in the creek.

They do that by grasping onto minnows that are attracted to the mussels when they open their shells.

Mussels spawn by depositing spores onto the tiny fish that then carry them off, spreading them across the system.

These are different than the zebra or quagga mussels that invaded the Great Lakes from ballast water brought in from overseas and altered its ecosystem. The clubshell mussel belongs here.

They help filter and purify the water by feeding on algae, plankton and silts; provide food sources and are monitors of aquatic health, according to the Fish & Wildlife Service.

“They’re good mussels,” Clancy said. “We have the opportunity to put them back.”

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