PORTLAND, Ore.— The Center for Biological Diversity filed a legal petition today with the U.S. Fish and Wildlife Service to protect the Crater Lake newt (also known as the Mazama newt) under the Endangered Species Act.

The newt exists only in Crater Lake, and its populations have plummeted in recent years because of warming lake temperatures and the expanding population of signal crayfish, a predator species introduced to the lake.

“These adorable little newts are clinging to existence and need immediate federal protections because of the introduced species that prey on them at every stage of their lives,” said Chelsea Stewart-Fusek, an endangered species attorney at the Center. “Without more funding for conservation this important species will be lost and Crater Lake’s ecology will be forever altered.”

The Crater Lake newt is a subspecies of the more widely distributed rough-skinned newt. While the rough-skinned newt possesses a potent neurotoxin to deter predators, the Crater Lake newt is adapted to being the lake’s top aquatic predator and lacks any predator defense mechanisms.

In the late 1800s fish were introduced to the lake to attract visitors, and in 1915 park managers introduced signal crayfish as a food source for the fish. Both fish and crayfish prey on the newt, but it wasn’t until lake temperatures warmed as a result of climate change that crayfish populations exploded and newt populations crashed.

Newts have disappeared where crayfish are present, and crayfish may now occupy up to 95% of the lake’s shoreline. Scientists anticipate that crayfish will occupy all of the lake’s shoreline in as little as two years. Crayfish also compete with newts for food, as both species feed on invertebrates. Where crayfish are present, invertebrate populations have been decimated.

Crater Lake is part of the National Park System and is famous for its status as one of the world’s deepest and clearest lakes. Crayfish threaten not only the newt, but the lake’s clarity as well — scientists have found that by preying on the lake’s native plankton-consuming invertebrates, crayfish increase algae growth in the lake.

Introductions of non-native species to water bodies — often by public lands managers — have had devastating consequences for native species and ecosystems and play a significant role in amphibian declines and extinctions worldwide. Eradicating harmful introduced species requires significant investments of time and resources.

“These little newts have flourished in Crater Lake for thousands of years, and we have a responsibility to ensure they remain part of its ecosystem for generations to come,” said Stewart-Fusek. “Losing the lake’s top native aquatic predator would mean losing a part of what makes Crater Lake so special to Oregonians and to the world. And losing them to introduced species and climate change illustrates how quickly our short-sighted actions can devastate our planet’s biodiversity.”

Park managers have made several attempts at crayfish removal, but none have been successful. Scientists recommend that more funding go toward crayfish removal efforts and that a comprehensive recovery plan for the newt be developed. Protection of the newt under the Endangered Species Act would address both recommendations.