Rare Find Spurs Hope for Spinymussel

When Zach Schumber decided to dig his fingers a little deeper into the Ocmulgee River bottom last month, the DNR aquatics biologist didn’t know he’d touch history.

But Schumber dug, felt a large mussel, pulled it loose and nearly spit out his snorkel. In his hand was a live Altamaha spinymussel, the first one seen in 15 years.

Schumber said he “immediately popped out of the water” to show the survey crew. “Everyone was like, Whoa!”

The palm-sized, coffee-colored mussel with four small spikes protruding from its shell was not only one of the continent’s most notable mollusks, it was one many scientists thought was gone.

Matt Rowe leads the DNR Wildlife Conservation Section’s Freshwater Biodiversity Program. “Me and pretty much everybody I talked with was about ready to call them extinct,” Rowe said, chuckling.

MYSTERY MOLLUSK

The Altamaha spinymussel (Elliptio spinosa), named for the short spikes or “spines” that protrude from its shell – spinosa means spiny or prickly – is known only from Georgia’s Altamaha River basin and has been in decline since the late 1970s. Why it’s fading is a mystery, Rowe said. But so is most everything about spinies, including which fish they use to spread their young and why they have spikes in the first place.

What is known?

That the last live Altamaha spiny documented before this was found on the Altamaha near Jesup in 2011, the year the species was federally listed.

That even the shells of dead ones, which littered Altamaha sandbars near Jesup in the 1970s and still fill drawers at the Georgia Museum of Natural History, are hard to find in the wild now.

That this species is considered extirpated – locally extinct – in the Oconee and Ohoopee rivers.

ONE MAY LEAD TO MORE

Schumber and technicians Percy Knight, Rachael Byrne and Gina Mondibrown weren’t looking for spinies on July 7. They were surveying the Ocmulgee below Jacksonville in Telfair County as part of an almost 10-year-old agreement with Georgia Power and the U.S. Fish and Wildlife Service to conserve five other mollusk species. (They found two of one of them – Altamaha arcmussel.)

Yet the Ocmulgee from there south to the confluence with the Oconee that forms the Altamaha is considered some of the more promising habitat for spinymussels.

The crew had sampled one site, spotted another where the habitat looked different and thought, why not? Once out of the boat, the packed sand-and-gravel river bottom piqued their interest. Within 10 minutes, they were tagging a species none of them had ever seen.

Rowe said the discovery doesn’t mean Altamaha spinymussels aren’t “functionally” extinct. But it raises hopes that others can be collected and used to learn how to propagate the species and bolster populations.

For Schumber, finding a spiny only months into his job as biologist for Georgia’s Atlantic slope waterways sets the bar high. “It’s going to be hard to top that,” he said.

MEET SPINOSA

• Profile: Large mussels usually sporting one to five spikes or “spines,” each no longer than an inch. Spinies seem to be limited to swift-flowing water.
• Range: First described in the Altamaha River near Darien in 1836, spinies were once found across the Altamaha and into the lower Ocmulgee, Oconee and Ohoopee rivers. They are now extirpated in the Oconee and Ohoopee.
• Roles: Like other mussels, spinies are filter feeders that improve water clarity (siphoning out pollutants and sediment), help stabilize riverbeds and serve as food for other animals. Their sensitivity to contaminants makes them keen indicators of stream health.
• Kind not kin: North America’s two other spinies, the Tar River and James spinymussel, are found in North Carolina, Virginia and West Virginia. They are also endangered, but neither is closely related to Altamaha spinies.
• Reasons: Why spines? DNR’s Matt Rowe lists three theories: Spines help  1) young mussels avoid being swallowed, 2) young and old anchor in substrate and 3) boost the mussel’s metal persona. “They’re rad,” Rowe adds.
• Process: The spinymussel found was tagged, measured, checked to see if it was gravid (it wasn’t), returned to the river and the location marked.
• Next steps: More surveys and work on a spinymussel recovery plan.
• Dig deeper: “To save a mussel, find its fish,” UGA Research (spring 2009)

Top: Altamaha spinymussel found in the lower Ocmulgee River (GaDNR)

Related

Legal Disclaimer:

EIN Presswire provides this news content "as is" without warranty of any kind. We do not accept any responsibility or liability for the accuracy, content, images, videos, licenses, completeness, legality, or reliability of the information contained in this article. If you have any complaints or copyright issues related to this article, kindly contact the author above.