HUNTSVILLE, Ala. (June 1, 2022) – A small, rare crayfish thought to be extinct for 30 years has been rediscovered in a cave in the City of Huntsville in northern Alabama by a team led by an assistant professor at The University of Alabama in Huntsville (UAH).
Dr. Matthew L. Niemiller’s team found individuals of the Shelta Cave Crayfish, known scientifically as Orconectes sheltae, in 2019 and 2020 excursions into Shelta Cave – its only home.
Dr. Niemiller, an assistant professor of biological sciences at UAH, a part of the University of Alabama System, is co-author of a paper on the findings in the journal Subterranean Biology. Besides Dr. Niemiller, authors are UAH’s Katherine E. Dooley and K. Denise Kendall Niemiller, and Nathaniel Sturm of the University of Alabama.
The crayfish’s home is a 2,500-foot cave system that’s owned and managed by the National Speleological Society (NSS) and is unobtrusively located beneath the organization’s national headquarters in northwest Huntsville and is surrounded by subdivisions and bustling roadways.
“The crayfish is only a couple of inches long with diminutive pincers that are called chelae,” Dr. Niemiller says. “Interestingly, the crayfish has been known to cave biologists since the early 1960s but was not formally described until 1997 by the late Dr. John Cooper and his wife Martha.”
But the aquatic ecosystem, including the Shelta Cave Crayfish, crashed sometime in the early 1970s. The crash may be related to a gate that was built to keep people out of the cave and yet still allow a grey bat maternity population to still move freely in and out.
Even before the decline in the aquatic cave community, the Shelta Cave Crayfish was never common compared to the other two species, Southern Cave Crayfish (Orconectes australis) and Alabama Cave Crayfish (Cambarus jonesi).
“To the best of our knowledge, only 115 individuals had been confirmed from 1963 through 1975. Since then, only three have been confirmed – one in 1988 and the two individuals we report in 2019 and 2020,” Dr. Niemiller says.
“After a couple of decades of no confirmed sightings and the documented dramatic decline of other aquatic cave life at Shelta Cave, it was feared by some, including myself, that the crayfish might now be extinct.”
While it’s encouraging that the Shelta Cave Crayfish still persists, he says scientists still haven’t rediscovered other aquatic species that once lived in the cave system, such as the Alabama Cave Shrimp and Tennessee Cave Salamander.
“The groundwater level in Shelta Cave is the result of water that works its way naturally through the rock layers above the cave – called epikarst – from the surface,” says Dr. Niemiller. “However, urbanization in the area above the cave system may have altered rates at which water infiltrates into the cave and also increased rates of pollutants, such as pesticides and heavy metals entering the cave system.”
The crayfish was rediscovered during an aquatic survey aimed toward documenting all life that encountered in the cave system.
“I really wasn’t expecting to find the Shelta Cave Crayfish. My students, colleagues and I had visited the cave on several occasions already leading up to the May 2019 trip,” Dr. Niemiller says. “We would be fortunate to see just a couple of Southern Cavefish and Southern Cave Crayfish during a survey.”
While snorkeling in about 15 feet of water in North Lake located in the Jones Hall section of the cave, Dr. Niemiller spotted a smaller-sized cave crayfish below him.
“As I dove and got closer, I noticed that the chelae, or pincers, were quite thin and elongated compared to other crayfish we had seen in the cave,” he says. “I was fortunate to swoop up the crayfish with my net and returned to the bank.”
“The second Shelta Cave Crayfish that we encountered was in August 2020 in the West Lake area,” he says.
The team had searched much of the area and didn’t see much aquatic life. As they started to make their way out the lake passage to return to the surface, Nate Sturm, a master’s student in biology at the University of Alabama who had accompanied the lab for the trip, noticed a small white crayfish in an area that the team had previously walked through.
To aid identification, the team analyzed short fragments of mitochondrial DNA in the tissue samples collected.
“We compared the newly generated DNA sequences with sequences already available for other crayfish species in the region,” Dr Niemiller says. “A challenge we faced was that no DNA sequences existed prior to our study for the Shelta Cave Crayfish, so it was a bit of a process of elimination, so to speak.”
Outside of the dissertation work done by Dr. Cooper, little about the life history and ecology of the species is known.
“Groundwater is critically important not just for the organisms that live in groundwater ecosystems, but for human society for drinking water, agriculture, etc.,” Dr. Niemiller says.
“The organisms that live in groundwater provide important benefits, such as water purification and biodegradation,” he says. “They also can act like ‘canaries in the coal mine,’ indicators of overall groundwater and ecosystem health.”
Dooley KE, Niemiller KDK, Sturm N, Niemiller ML (2022) Rediscovery and phylogenetic analysis of the Shelta Cave Crayfish (Orconectes sheltae Cooper & Cooper, 1997), a decapod (Decapoda, Cambaridae) endemic to Shelta Cave in northern Alabama, USA. Subterranean Biology 43: 11-31. https://doi.org/10.3897/subtbiol.43.79993
About The University of Alabama in Huntsville
Launched from America’s quest to conquer space, The University of Alabama in Huntsville is one of America’s premier doctoral-granting, research-intensive universities. Located in the second largest research park in the United States, UAH has robust capabilities in astrophysics, cybersecurity, data analytics, logistics and supply chain management, optical systems and engineering, reliability and failure analysis, rotorcraft and unmanned systems, severe weather, space propulsion and more. UAH prepares students for demanding positions in engineering, the sciences, business, nursing, education, the arts, humanities and social sciences.
Read the full press release by The University of Alabama in Huntsville.