Biologists find St. Louis Zoo-raised hellbender with eggs in Current River, a milestone

Biologists find St. Louis Zoo-raised hellbender with eggs in Current River, a milestone

ST. LOUIS — The discovery of a clutch of eggs in the Current River in southeast Missouri is a Champagne-popping moment for the St. Louis Zoo and the Missouri Department of Conservation.

The proud papa is an endangered Ozark hellbender reared at the zoo for six years before being released in 2019.

“This is the first documented event of a zoo-raised animal fathering a clutch of eggs in the wild,” Missouri herpetologist Jeff Briggler said in a statement.

The milestone is a hopeful sign that the species could rebound, the Department of Conservation said. The Ozark hellbender, a large aquatic salamander, has dwindled to fewer than 1,000 in southern Missouri and northern Arkansas, a region that once held more than 27,000.

First zoo-raised Ozark hellbender reproduces in the wild

The first zoo-raised Ozark hellbender to successfully reproduce in the wild pictured above, is held by Missouri State Herpetologist Jeff Briggler. The animal was raised from a clutch of eggs at the Saint Louis Zoo and released on the Current River in 2019.

In 2011, it was added to the federal endangered species list.

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Loss of habitat and water pollution are partially to blame for the salamander’s struggles, according to the conservation department. Because hellbenders, which live about 30 years, require cool, clean, well-oxygenated water, the species is an indicator of the overall health of a river’s ecosystem.

They absorb oxygen through the many wrinkly folds of skin along their flanks, which have earned them the nickname “old lasagna sides.” They’re also the subject of Ozark and Appalachian folk tales, with monikers such as the Allegheny alligator, snot otter, mud devil and grampus.

Missouri, the St. Louis Zoo and other agencies began working together in the early 2000s to breed the salamanders in captivity.

At the zoo, they’re raised in the Ron and Karen Goellner Center for Hellbender Conservation, in the lower level of the zoo’s herpetarium.

First Ozark hellbender raised in captivity reproduces in wild

The Missouri Department of Conservation announced April 13, 2023, that the first zoo-reared Ozark hellbender has successfully fathered a clutch of eggs (pictured) on the Current River. MDC partnered with the St. Louis Zoo and other agencies to restore threatened hellbender populations to Missouri.

It has taken years to figure out the right temperatures and conditions for the hellbenders to thrive.

In 2008, biologists began releasing a few zoo-raised hellbenders in Missouri. In 2012, they increased the number to at least 1,000 per year.

Most are only now becoming mature enough to breed, the state said.

This new father’s story began almost a decade ago, when a nest of eggs was collected from the Current River and taken to the zoo to hatch.

In July 2019, when the amphibians were big enough and strong enough to survive, they were released back to the river, with identification chips placed under their speckled skin.

Conservation workers found this tagged hellbender in October attending a clutch of 128 healthy eggs. When workers returned later, the eggs were hatching and the father was protecting them.

When he was released into the river almost four years ago, he was 12-inches long and about the weight of a hockey puck. When biologists discovered his nest, he had grown 2½ inches and gained more than half of his earlier weight, they said.

More than 10,000 hellbenders raised at the zoo or the conservation department’s hatchery have been returned to their native rivers in the past 15 years.

But very few nests with eggs have been uncovered.

“Finding a tagged father that was raised at the Saint Louis Zoo was like finding a needle in a haystack,” Briggler said in the statement. “We have been patiently waiting for this significant achievement to occur.”

Justin Elden, a herpetology curator at the zoo, called the discovery one of the greatest accomplishments for the zoo’s conservation efforts.

“We are incredibly proud,” he said in the statement, “to be partnered with the MDC on saving this species.”

Colleen Schrappen of the Post-Dispatch contributed to this report.

Hellbender keeper Katie Noble collects a clutch of Ozark hellbender eggs after diving into the nesting stream outside the Herpetarium at the St. Louis Zoo on Sept. 27, 2022. The stream is part of the captive breeding program aimed at saving the threatened species.

Helping the hellbenders: St. Louis experts work to breed struggling species