The mission of the U.S. Fish and Wildlife Service's Endangered Species program is conserving and restoring threatened and endangered species and their ecosystems.

The Ozark Hellbender

Can We Save It?

The Ozark hellbender (Cryptobranchus alleganiensis bishopi) if found in rivers and streams in northern Arkansas and southern Missouri. Photo by Jeff Briggler

What lurks below the clear waters of Ozark streams?

Well, it’s not pretty but it is pretty cool. The Ozark hellbender, at about 2 feet long, is one of the largest salamanders in the world.

The news is not so good for hellbenders. They’re declining in numbers throughout their range, with numerous threats to them and their habitat - so much so that in 2001 it was designated as a candidate for listing under the Endangered Species Act.

Ozark Hellbender Trivia • they are strictly aquatic salamanders found only in Ozark streams of southern Missouri and northern Arkansas. • their body shape is flattened from top to bottom which helps them move about in fast-flowing waters • numerous fleshy folds along the sides of their bodies provide surface area for respiration • most of their time is spent beneath rocks in fast-flowing streams • at night, they come out from beneath their rocks to eat crayfish, and in the fall to mate •it takes them 5 to 8 years to reach sexual maturity •they live 25 to 30 years in the wild •males and females may prey upon their own and others’ eggs

Because of their long lifespan, researchers did not readily recognize the rate or the rapidity of the decline. At this point in time, numbers of hellbenders, even in areas that recently were thought to have healthy, stable populations, have plummeted. Particularly disconcerting, most populations have only older, large individuals. The lack of juveniles indicates that there has been little to no reproduction for several years.

What happened? The Ozark area is famous for its beauty and fast, clear rivers, which are fun to canoe, kayak, and fish. But that clear water and pretty scenery can be deceiving. The story of the Ozark hellbender’s decline is an all too familiar one – increased siltation, water quality degradation, and increased impoundments.

To add insult to injury, a highly infectious disease caused by Batrachochytrium dendrobatidis has been found in the Missouri populations. This “chytrid fungus” is proving fatal to an ever-increasing number of amphibians throughout the world. Of all the deaths that occurred in the St. Louis Zoo’s captive population from March 2006 through April 2007, over 75 percent were due to this disease. This prompted the testing of Missouri’s wild Ozark hellbenders.

The results showed that the chytrid fungus was present in all remaining populations of the Ozark hellbender in Missouri. Testing continued in Missouri during the 2007 field season and began in Arkansas. Researchers view chytrid as one of the most, if not the most, challenging threat to the survival of this subspecies whose population size is estimated to be, at most, 590 individuals.



Additionally, abnormalities in Ozark hellbenders are becoming increasingly more severe, often to a level that the animal is approaching death. Although these abnormalities have not been linked conclusively with the presence of chytrid, considering that the types of abnormalities documented (e.g., lesions, digit and appendage loss, epidermal sloughing) are similar to the symptoms of the chytrid fungus, it is possible that there is a connection.

Hope remains, however, with conservation efforts ongoing.

A group of dedicated professionals formed the Ozark Hellbender Working Group shortly after the species was made a candidate. Original members were researchers and agency personnel with common interests in hellbender conservation. Staff from hatcheries, zoos, and other interested entities later joined. The group has collaborated on field work, initiated research projects, and they are working to uncover the primary threats to the species' persistence. The group is also developing a comprehensive conservation strategy that will include a captive propagation protocol, an outreach strategy, and a watershed protection plan.

Interest in conserving hellbenders (both the eastern and Ozark) is high and has spurred establishment of biennial Hellbender Conservation Symposiums. Three Symposiums have been held so far, with the first in 2003 and the latest in 2007. They provide opportunities for conservationists to share information and discuss topics such as hellbender status and distribution reports, current research, status of captive breeding programs, survey and monitoring protocols and techniques, and proactive conservation efforts. Focused research efforts and collaboration between researchers and natural resource managers are necessary to reverse the decline of hellbender populations. The symposiums provide a perfect venue for kick-starting that collaboration.

There are several ongoing research projects directed at learning how best to decrease threats and increase survival of hellbenders in the wild and captivity. Researchers at the University of Missouri-Rolla are evaluating overall health conditions, reproductive hormones, and contaminants present in adult and juvenile hellbenders through hematology and serum chemistry work. Survival and movements of resident adult and released captive-reared Ozark and eastern hellbenders are being studied by researchers from the University of Missouri (Columbia) and Missouri Department of Conservation. And the Missouri Department of Conservation and the St. Louis Zoo have been collaborating in developing a propagation protocol for the subspecies.

Missouri and Arkansas are conducting activities that either directly or indirectly conserve hellbenders. Missouri provided extra protection for the hellbender in the Wildlife Code of Missouri, outlawing collection of hellbenders, and the species was listed as State Endangered in 2003. Outreach has been considerable in Missouri and Arkansas to protect hellbenders from recreationists; there are now signs throughout the range of the hellbender alerting recreationists to their presence and informing them that hellbenders are harmless and should be left alone or released unharmed if they are caught by anglers.

Recovery of aquatic species is extremely challenging, more so than for terrestrial species, because the threats are diffuse and thus more difficult to identify and address. The Ozark hellbender’s situation is also a sign of the times in endangered species conservation, as global threats are added to those from local land use and climate change becomes a factor. Not easy times, but conservationists are rising to the challenge by looking beyond agency and geographical boundaries to collaborate and share resources, prioritize limited dollars, and persevere.

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