Wildlife Diversity Program Quarterly Report for April–June 2025
Damage to the Swannanoa River from Hurricane Helene, near the WNC Nature Center, Asheville, fall 2024. Before the flood, this site had a positive eDNA sample for East- ern Hellbender.
ANDREA LESLIE/NCWRC
Detections of Eastern Hellbenders Post Hurricane Helene
by Lori Williams, Western Amphibian Biologist
S ince 2012, we have successfully used environmental DNA (eDNA) water sam- pling as a quick way to survey and monitor streams for the presence of state listed (now, federally proposed, endangered) Eastern Hellbenders (Cryptobranchus a. alleganien- sis) . Post-Hurricane Helene, we are relying on this rapid assessment technique more than ever to begin to understand which Hellbender populations were hit the hard- est by such a devastating, landscape chang- ing event. In the second quarter of 2025, we began focusing eDNA water sampling on historical Hellbender sites ravaged by Helene, such as the Swannanoa River drainage in Buncombe County. The Hellbender population was already poor in this system, yet the Swanna- noa River still produced five positive eDNA samples from 2018-2021 over many miles of river. However, this spring, in the first sam- pling since Helene, 100% (18 out of 18)
water samples taken throughout Swannanoa River were all negative, meaning not a single Hellbender was detected. Thankfully, one tributary of the Swanna- noa system that also had a poor population pre-Helene, produced three out of seven positive eDNA samples in this same survey window, indicating that at least a few ani- mals survived the flood in that tributary. Those animals may be the last of their kind in the whole drainage. For the Swannanoa River itself, Hurri- cane Helene appears to have wiped out this unique species. The last physical records of Hellbenders in Swannanoa River were in 2021, when we rescued and relocated six animals out of harm’s way during a complex, multi-phase, multi-year river restoration project at Veterans Park in Black Mountain. Sadly, Hurricane Helene negated those resto- ration efforts and much more.
BEN DALTON/NCWRC
Above: One of six Eastern Hellbenders rescued and relocated out of harm’s way at the river restoration project in Swannanoa River, Spring 2021. Since Hurricane Helene’s destruction, we now look back and realize this animal was likely one of the last Hellbenders to have lived in Swannanoa River.
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