Photo: Oregon Zoo

Twenty tiny, frilly-gilled Mazama newts, each no bigger than a sunflower seed, have emerged from their eggs at the Oregon Zoo this month — thrilling conservationists who have eagerly anticipated the first of these imperiled amphibians to hatch under human care.

Mazama newts — a rare subspecies of rough-skinned newt found only at Crater Lake — arrived at the Zoo last summer as part of an emergency conservation effort.

Zoo care staff didn’t know what to expect during the inaugural breeding season, but two of the newts laid eggs this spring. Keepers checked on the eggs daily under a microscope, using methods developed for axolotl eggs to chart their progress.

Finally, on July 19, one egg hatched. Then the next day, another. And the next day, another.… In all, 20 newtlets have arrived so far, and more eggs appear to be fertile and developing.

“It’s exciting and nerve-wracking,” said Kaley McClung, a keeper in the zoo’s newt conservation lab. “These hatchlings are exactly what we’ve been hoping for since the newts first arrived here. They may be tiny, but they represent a huge and hopeful step for everyone involved.”

During their first few days, the newly hatched newts get all their nutrients from a yolk sac. But keepers have already offered some brine shrimp and seen darting and pouncing behavior — signs of a healthy appetite.

Although there is a chance the hatchlings won’t survive, simply reaching this milestone sparks optimism for the conservation effort.

“Right now, our focus is simply to keep Mazama newts from going extinct,” said David Hering, an aquatic ecologist at Crater Lake National Park. “There's still a long road ahead before we can return them to Crater Lake, but this breeding success is a critical milestone and an encouraging sign that recovery is possible.”

Working with the National Park Service, the zoo hopes to raise the newts until they're large enough to survive in the wild and eventually return them to Crater Lake, helping bolster the remaining wild population. Historically, Mazama newts were an abundant aquatic predator in the lake, but invasive signal crayfish have spread along much of the shoreline, dramatically reducing their numbers. Beyond threatening the newts, the crayfish also disrupt the foundation of Crater Lake's ecosystem.

This summer, while work at the lab continues, the Oregon Zoo, National Park Service and Southern Oregon University are preparing a potential release site for zoo-bred newts. By studying and removing invasive predators from an isolated pond at Crater Lake, the partners hope to create a protected refuge where newts can survive and reproduce while a long-term solution to the invasive crayfish problem in Crater Lake is developed.

The Mazama newt has been included in Oregon’s revised State Wildlife Action Plan and has been petitioned for listing under the Endangered Species Act. Partners in the conservation effort include the National Park Service, High Desert Museum, U.S. Geological Survey, Oregon State University, University of Illinois, University of Washington, San Antonio Zoo and St. Louis Zoo.

Source: Oregon Zoo

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