Scientists Seek to Save Once-thriving Hellbender
by Sara Shipley, St. Louis Post-Dispatch
October 24, 2004
TECUMSEH, Mo. - Insulated by a thick black wet suit, Mauricio Solis slipped under the surface of an Ozark stream in search of a prehistoric creature. He turned over heavy rocks one by one, scanning the bottom for a slippery figure the color of rotting leaves.
The cold, oxygenated water of the White River's North Fork holds some of the last remaining members of an amphibian family that has roamed this planet for 150 million years. The hellbender salamander has survived dinosaurs, tectonic shifts and multiple ice ages - only to nearly disappear in the time it took for bell-bottom jeans to come back in style.
"Back in the '70s, on a day like today, we'd have gotten 100 hellbenders," Solis said on this October day, "and today we got four."
Solis, a graduate student at the University of Missouri at Rolla, is part of a biological SWAT team aimed at finding out what's hurting the hellbender. Armed with water sampling equipment, electronic tags, laboratory tests and plans for a captive breeding program, a coalition including state and federal agencies, universities and the St. Louis Zoo hopes to arrest the animal's slide into oblivion.
Scientists believe that the fate of North America's largest salamander could hold clues to the health of the human race. Amphibians are sometimes called "canaries in the coal mine" because their highly permeable skin is sensitive to subtle changes in air and water quality.
The hellbender makes a particularly interesting surrogate, because the 2-foot-long animal can live up to 50 years. Its native Ozark streams appear crystal clean to the naked eye, yet something is clearly wrong.
"Why are they declining? I don't know," Solis said. "Hopefully they will stay around long enough so we can find out what's going on."
Thirty years ago, Missouri was hellbender heaven. The state is the only one to have both subspecies of the now rare animal. The Ozark hellbender lives only in southern Missouri and northern Arkansas; the Eastern hellbender has been found in 16 states, including the Wabash River basin in eastern Illinois.
Described by one researcher as "so ugly only its mother could love it," the hellbender has a large, flat head made for slipping under rocks, tiny, beady eyes and a mottled, brownish color. It breathes underwater through the folds of its baggy skin, looking as if it's dressed in pajamas two sizes too large.
Missouri native Max Nickerson, considered the "godfather" of hellbender researchers, grew fond of the animals when he surveyed the North Fork in the late 1960s.
"It was amazing, because after I got into the water, I began to find hellbenders all over the place," recalled Nickerson, now a biologist at the University of Florida in Gainesville. "The population was astronomical. I caught and released 96 in one day."
Hellbenders appeared robust through the 1970s and '80s, but alarms began to sound in the '90s as people reported a scarcity of the animals. The Missouri Department of Conservation commissioned a survey of all hellbender streams in the late 1990s.
"What we found was, in every single river we surveyed, population numbers had decreased by 75 to 85 percent," said Alicia Mathis, a behavioral ecologist at Southwest Missouri State University in Springfield. "That was pretty shocking."
Not only were there fewer animals, the population also had aged substantially. In a trend that continues to this day, most animals found were older adults. Juveniles, eggs and larvae were nearly impossible to find.
It appeared that hellbenders were not reproducing, or something was killing the young. What could have nearly wiped out a species in just a few decades?
Many obvious threats had risen over the past century. Logging, dams and development have cluttered Ozark streams with gravel and silt and robbed them of oxygen. Farming, mining and development taint water with chemicals that were unknown to the hellbender for millions of years.
Trout introduced for sport fishing may eat hellbender eggs and larvae. Some animals have been taken for research, poached for the pet trade or killed by fishermen.
Looking for causes
Yet these factors alone don't seem to explain the puzzle. Missouri scientists suspect another contributing factor: Endocrine-disrupting chemicals could be throwing the animals' reproductive systems out of whack.
Some pesticides, fertilizers, plasticizers and other chemicals can mimic hormones, wreaking havoc on endocrine systems that regulate growth, reproduction and other functions. Some evidence suggests that these contaminants affect wildlife, as alligators, frogs and fish show up with abnormal sex organs.
Yue-wern Huang, an assistant professor of environmental toxicology at the University of Missouri at Rolla, leads a team looking at chemicals in Ozark stream water and in hellbender blood. University researchers have detected several endocrine-disrupting chemicals in Ozark streams where hellbenders live, but more work is needed to tell whether the chemicals are present at levels that could cause harm, Huang said.
"There's a generation gap there, that shows they're not reproducing successfully," Huang said.
Basic blood work has been done; now Huang wants to look at the ratio of estrogen and testosterone in the animals. He also hopes to look for a telltale protein that acts as a marker for exposure to hormone-disrupting chemicals.
Killing animals to dissect their reproductive organs is not an option because there are too few specimens left. "When it gets too late, it makes it hard for scientists to do their work," Huang said.
In a separate study, Mathis found that Missouri hellbenders had lower sperm counts than their counterparts in North Carolina and Georgia, where populations are healthy.
She pointed out that people may suffer from a similar problem. Men from rural Missouri had lower sperm counts than men from Minneapolis, Los Angeles and New York, according to studies by a University of Missouri at Columbia researcher who suggested that agricultural chemicals such as atrazine could be to blame.
The science of endocrine disruption is young and controversial. Pesticide manufacturers have disputed the Mizzou studies, saying that many studies and years of use show the chemicals to be safe and effective.
"Whether or not that's the cause of the decline remains to be seen," Mathis said. "But it is definitely a suggestion that needs to be investigated more."
Fixes may be costly
Fixing what ails the hellbender could require significant changes in the Ozarks, a remote area heavily dependent on tourism dollars from anglers, canoeists, hikers and campers.
The Missouri Conservation Department and the U.S. Fish and Wildlife Service, both of which are trying to recover the hellbender, must grapple with whether their trout-stocking programs are part of the problem.
"Fishery biologists around the world are looking at the impacts these animals are having on the native diversity," said Jeff Briggler, a herpetologist with the Missouri Conservation Department who says hellbenders are close to his heart. "This has been on our radar screen, and we need to evaluate it a little more."
To address the issue, Mathis is studying whether baby hellbenders from Missouri recognize trout as a predator. Her early work shows they do not.
"In addition to the problems with reproduction, we're concerned that the larvae that do get produced are being picked off by trout," Mathis said. "It may be a one-two punch."
Canoeists that crowd popular Ozark float streams on summer weekends could play a role too, as they dump trash and take bathroom breaks in the river, several researchers said.
Restricting the number of float permits would undoubtedly cause a furor. Briggler said it's too soon to suggest such a drastic move.
"I think you could have millions of people going down these rivers, if you could get everyone to get out of the river and urinate on the bank, and not throw their trash in the river," he said. "We just need to be more mindful."
Until scientists understand the long-term solution, several moves are afoot to put the hellbender on life support.
The Missouri Coalition for the Environment has petitioned the U.S. Fish and Wildlife Service to list the Ozark hellbender as an endangered species. Currently, the hellbender is listed as endangered by the state of Missouri, meaning it is illegal to kill or keep the animal in captivity without a permit. A federal listing would help protect the animal's habitat and encourage additional funds for studying it, said Ted Heisel, executive director of the coalition.
"It's important that they take the formal step of listing it," Heisel said. "The Fish and Wildlife Service has known for several years now that the species is in really big trouble."
Amy Salveter, a fish and wildlife biologist with the federal agency, said she is doing everything she can to save the hellbender. The agency recently moved the animal up on its priority list of candidates for endangered species listing.
Zoo lends a hand
Meanwhile, the St. Louis Zoo has turned to a solution of last resort. The Zoo obtained a permit to remove up to three pairs of hellbenders from the wild to breed them. Solis helped two Zoo staff members and a volunteer capture four animals on a trip this month.
The team moved slowly through the rushing water, faces submerged, looking for signs of life. Once caught, the animals wriggled violently.
"They're slippery as all get-out," said Peter Taylor, manager of the Zoo's herpetarium. "It's like live Jell-O."
Solis waved a device over the tail of each animal to detect whether it had been tagged as part of ongoing research at the University of Missouri at Rolla. The rice-grain-size tags, implanted just under the skin, record an identification number linked to data on the animal.
One hellbender was missing a leg and several fingers - a phenomenon that has become alarmingly common.
"We sure don't know what's going on there, but we need to find out," said Ron Goellner, the Zoo's general curator, who has studied hellbenders in the Ozarks for 30 years.
Three of the captured salamanders were brought back to the Zoo, where they now live in an artificial stream Goellner built in the basement of the reptile house. Purified water circulates in a knee-high, 32-foot-long chamber lined with gravel and rocks.
Nearby, 15 aquarium tanks hold about 150 young hellbenders Mathis and her students raised by hand from rare clutches of eggs found in the wild. Keepers feed the 2-year-old salamanders krill and worms.
These youngsters will be studied and perhaps bred one day. Zoo officials hope to have enough offspring so that they could return some animals to the wild eventually.
Taylor and Goellner will meet with other members of the Hellbender Working Group at the Zoo on Nov. 5 to discuss the creature's survival.
For Salveter, the hellbender offers people a chance to work together to protect something special."I'm not saying the hellbender is a sexy, endearing creature that everyone is going to want to latch onto, like a whooping crane or a grizzly bear, but it sure is unique," she said. "I think we need to heed these early warning signs. We should really be paying attention."
Republished with the permission of the St. Louis Post-Dispatch.
Copyright 2004 St. Louis Post-Dispatch
Courtesy of STLtoday.com