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David Herasimtschuk photo
Eastern hellbender
Eastern hellbender.
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David Herasimtschuk photo
On the prowl
David Hedrick hunts for hellbenders.
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David Herasimtschuk photo
Catch and release
Hedrick showing off a recently caught hellbender.
Even on a hot July day, the creeks of Roane County are cold enough to need thick wetsuits. Outfitted with snorkels and fins, divers explore the shallow creek’s rocky bottom on a hunt for the elusive hellbender, North America’s largest salamander species. Guide David Hedrick, lead ectotherm keeper at the Chattanooga Zoo, has dedicated his life to studying hellbenders. Earlier this year, he received a one-year grant to conduct new research that may be the start to bringing the hellbender back to Walden Ridge and preventing their extinction in Tennessee.
“We need to identify the healthy populations and move toward preserving the best habitat and maintaining numbers there,” Hedrick said. Averaging 15-19 inches long, the hellbender lives to about 50 years old in the wild and has existed the last 150 million years on earth. Searching for the salamanders feels like combing a great green field for a four-leaf clover. During the day, hellbenders reside underneath boulders where their flat, mottled-gray bodies provide perfect camouflage. Hedrick and his co-researcher, Michael Freake, biology professor at Lee University, lift rock after rock for hours in search of hellbenders.
Hedrick’s fascination with hellbenders started when he read the Guinness Book of World Records as a child. “I saw those old photographs of the world’s largest salamanders, the Chinese giant salamanders; I was stoked on that and talked about them with my dad,” he said. His father then told him stories about how he and many older locals used to catch several back in the 1970s.
“When I was a kid, every time we drove across the south Chickamauga bridge heading to downtown Chattanooga, I would peer through the window to see if I could find one,” Hendrick said. In 1986 at 13 years old, Hedrick caught his first hellbender while fishing on the Hiwassee. “It felt unreal to catch something like that, which was such an enigma to me,” he said.
Now, 30 years later, he still looks for hellbenders, but with a new piece of technology instead of a net. Environmental DNA determines if hellbenders inhabit the stream by finding any DNA floating in the water from shed skin. Using this technology and catch-and-release, Hedrick tracks hellbenders, their age and any sign of eggs to determine if research sites are home to old salamanders, none at all or a breeding population.
“I’m looking at Walden Ridge creeks to figure out if these streams have been restored enough to support hellbenders,” Hedrick said, as he took a break by the side of the water. “Really what it boils down to is should we do anything here or not?” The pool he was searching looked pretty good. The water was clear enough to have seen the many swimming bass and logperch darters and have found species such as the native freshwater mussel and its non-native cousin the Asian freshwater mussel, as well as crayfish, which make up much of a hellbender’s diet. Hedrick and Freake logged everything. Over the next year, their information collected from eight similar river bodies will help piece together the most up-to-date picture of the status of Cryptobranchus alleganiensis in Walden Ridge and Tennessee.
Historically the picture has looked pretty grim. Before the 1960s, hellbenders were common creatures, and their habitat range spanned from Alabama up to New York and over to Arkansas. Then during the 1970s and ‘80s their population took a devastating hit, which researchers attribute to several factors include siltation from dams and increased land development that dirty the water, which hellbenders need to be clear for oxygen filtration. Fertilizers from agriculture run into streams, causing algae to grow and use all the oxygen hellbenders and other species need. Coal and copper mining runoff have polluted much of Middle Tennessee’s watersheds. Because of these impacts, most all of Tennessee’s streams west of Chattanooga have no hellbenders, save a few lone, old ones in random pools high in the watersheds.
The last hellbender strongholds border between east Tennessee and western North Carolina. Oddly enough, Tennessee’s biggest haven for hellbenders is the dammed Hiwassee River. In the 1940s, the Tennessee Valley Authority built hydroelectric dams on the Hiwassee, which changed the river’s temperature and killed off most of the native fish. The water was cold enough for stocked fish such as rainbow and brown trout, however, and the Tennessee Wildlife Resource Agency took advantage. Now, the TVA works with the TWRA to manage the Hiwassee as a river system for a trout fishery, which also makes a great environment for hellbenders. Hedrick says the Hiwassee is an example where fishermen and environmentalists ultimately want the same thing: a healthy watershed. In terms of river management goals, Hedrick said, “What’s good for the trout is good for the hellbender.”
Hellbenders mark the health not only of good stock-fish habitat but of the entire watershed and local forest ecosystem. “I look at things like hellbenders as the canary in the mine,” said Steve Scarborough, cofounder of Dagger Canoe Company. Hellbenders are so sensitive to environmental changes that a reproducing population means everything flowing into the watershed is clean and healthy. Seeing no hellbenders where history shows they once existed means trouble.
“As the river gets worse, you lose all the hellbenders, then the next species goes and the next until eventually the canary is you,” he said.
Scarborough volunteers for a few conservation groups including non-profit company Conservation Fisheries. He also joined his local community’s effort to shut down ATV access to upstream watersheds, which are intregal to the health of the overall watersheds. For example, a few months after the Cherokee National Forest Service shut down ATV access, fishermen in Tellico Plain, Tenn. noted the Tellico River’s quality had improved.
Hedrick and Freake look to supplement these preservation goals with an eventual reintroduction program to bolster hellbender populations at Walden Ridge and in other areas of Tennessee. In 2012, the Nashville Zoo successfully bred the first eastern hellbenders in captivity using hormonal injections. The Chattanooga Zoo has 10 resident salamanders, four of which are in a 40-foot pool while the others remain in tanks. Hedrick has spent the last three years tweaking water temperatures, oxygen levels and pH levels to make the perfect breeding and egg-producing environment so that he will not have to use hormones. “Hellbenders are incredibly picky,” he said.
However successful preservation and reintroduction are, the hellbender likely never will see healthy numbers again. Hedrick says the huge fragmentation of the East Coast’s river systems has dealt a heavy blow both to hellbenders and to all native animals.
“You’ll always have to monitor these populations because most of our stream miles have been so negatively impacted,” he said. “It’s like the entire eastern United States is one compromised ecosystem.”