SCIENCE WEDNESDAY -- August 7, 2013 at 12:54 PM ET
Rustling River Monsters for Science
Matt Neff from the Smithsonian's National Zoo holds a hellbender salamander that he caught in the Blue Ridge mountains of Virginia. Scientists hope to learn how healthy and viable the population is. Photo by Rebecca Jacobson
It takes six scientists to catch one hellbender salamander: three to lift the rock, two to hold the fishing nets, and one to dive underwater and grab the creature. Then, holding on is its own challenge, because the animals ooze clear slime from their skin when threatened. "It's like grabbing an eel covered in Crisco," said Kim Terrell, a postdoctoral researcher from the Smithsonian's National Zoo.
At the end of a long day snorkeling in the clear streams of southwestern Virginia's Blue Ridge Mountains, Terrell and her team assumed their positions. As three scientists lifted a flat, heavy rock, Terrell groped underneath the stone, let out a muffled cry through her snorkel mask and popped out of the water.
"Where did it go? Did you see it?"
The biologists checked their nets and scoured the water. Sarah Colletti from the Aquatic Wildlife Conservation Center pointed at the slick rocks under the water. "Right there, he's looking right at you." One of the biologists lunged, secured a firm grasp, and triumphantly pulled it out: a nearly two-foot long hellbender.
Slide show by Rebecca Jacobson.
Hellbender salamanders are long, flat, slippery amphibians that live underwater in clear mountain streams, under rocks that can weigh up to 1,800 pounds. Their coloring is a mottled green-brown that blends into the river bottom; they have wide flat heads, beady eyes and stubby toes.
While they've been around for 170 million years, scientists know little about them. There has never been a comprehensive national survey. Biologists surveyed areas in the past, but pinning down the exact size and territory of the population is tricky, said J.D. Kleopfer, a herpetologist from the Virginia Department of Game and Inland Fisheries, who is helping Terrell locate hellbender salamanders in the state. (He calls them "snot otters," affectionately.)
Terrell and her partners across the country are leading an effort in hopes of changing that. They've been surveying the population across the eastern United States for the last three years to determine the health and viability of the population.
And it's no easy task. Their work involves trudging up and down mountain streams and flipping enormous boulders. Unlike tracking a deer, there's no trail to follow. To narrow down the search, they have plans in the near future to use DNA sampling technology to search for traces of hellbender DNA in the streams.
Once caught, getting the creature back to shore for study is like a salamander rodeo. Back at the Blue Ridge mountain streambed, Derek Wheaton, a natural resource specialist at Virginia Department of Game and Inland Fisheries, starts a timer on his wristwatch. The hellbender thrashes, whipping its wide flat head around to its keeled tail. Wrapping the salamander in a wet towel, one team member holds it down while another -- Terrell -- draws a blood sample from its tail. The blood sample will measure the animal's stress hormone levels and tell her if it is fighting any infections. The team must get the sample quickly; the longer they wait, the higher the stress hormones from its capture could climb, leading to a false reading about its daily stress levels.
Watch a researcher release a hellbender into the water. Video by Brian Gratwicke/Smithsonian's National Zoo
"Imagine if I burst into your office one day, tackled you, stuck a needle in your butt and then measured your stress levels," Terrell explained.
They draw this sample in three minutes flat and then start taking measurements -- length, weight, sex. They inject a microchip into the hellbender's tail, the same kind of identification chip vets use on dogs and cats. When researchers capture the same animal in the future, this will allow them to identify it and track changes in its health.
Hellbenders are a "canary in the coal mine" species, meaning their health is an indicator for the health of the water and the environment around them, Terrell says. As a completely aquatic species, they breathe through their skin, which makes them highly susceptible to any pollutants in the water. Runoff from agriculture, mining and energy development sends silt and pollution into their streams, choking the salamanders and causing them to disappear from once populous habitats. The salamanders appear to have vanished from once-reported habitats in Ohio and Illinois, for example. Their numbers have reportedly dropped so low in the Ozarks that the Arkansas and Missouri subspecies was listed as endangered in 2011.
Hellbenders may also be affected by climate change--something Terrell is studying in her lab research. Warmer water carries less oxygen, making it difficult for the salamanders to breathe, she explained. And water temperature also seems to affect their reproduction. In fact, she said, it's unclear if hellbenders will continue to breed in warmer waters.
On the flipside, finding a hellbender in your stream is a good sign, said Mike Pinder, wildlife diversity manager for Virginia Department of Game and Inland Fisheries. Hellbenders can live as long as 50 years -- that's ancient for an amphibian, he said. By studying the health of the hellbender population, scientists can draw conclusions about their habitat's quality and stability.
"If you have hellbenders in your stream, that means you've had good water quality for a long time," he said.
Humans pose a threat to the species. Pinder says some trout fishermen have been known to catch the salamanders and kill them, fearing that the giant amphibians are eating their fish. Killing hellbenders is illegal, but he still sees hellbenders with spikes driven through their heads or even tacked to trees.
They are also highly valued in the black market pet trade, sold by poachers for hundreds of dollars.
But removing even one adult from its river has serious consequences, Terrell said. Hellbenders can live to 30 years old in the wild, but they grow slowly and take years to reach sexual maturity. That means every breeding adult is essential for the population's survival.
Securing the necessary funding to study this species has been difficult. Salamanders "don't have a voice," said Matt Neff, who cares for the animals at the Smithsonian National Zoo's reptile and amphibian house.
"I often have to explain to people that a salamander is not a reptile," he said. "Frogs sing, turtles are cute, but people have a harder time connecting with salamanders."
But they are surviving, even thriving, in unexpected places. Eric Chapman with the Western Pennsylvania Conservancy said that he's been surprised by some of the places the amphibians have turned up. He recently found a large population of hellbenders living in parts of Pennsylvania's Clarion River, which was believed to be uninhabitable for the salamanders.
"They're not a highly visible. They're not cute and cuddly," Chapman said. "But I just love them. Every time I touch one I think they're just spectacular."
Learn more about the Smithsonian's National Zoo salamander research on their website.
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