The Crater Lake newt only exists in the rich, blue waters of the Oregon national park. Its population has been declining in recent years, mostly due to growing numbers of signal crayfish. The crayfish are predators of the newt that were introduced to the lake in 1915 as a food source for fish, which were added in the late 1800s to attract visitors.
Chelsea Stewart-Fusek, an endangered species attorney at the Center for Biological Diversity, said the crayfish have a number of negative impacts on the newt.
"The crayfish will eat just about anything. So they'll eat the invertebrates, which newts would ordinarily consume, as well as the newts themselves. They're both predating on the newt and also competing for resources, for food and for cover as well," she said.
The Crater Lake newt, also known as the Mazama newt, is a subspecies of the rough-skinned newt and has no predator defense mechanisms. As the temperature of the lake has warmed due to climate change, the number of crayfish has exploded, threatening the newt's existence.
Crater Lake's surface temperature during the summer has increased by 3.2 degrees Celsius since records were first collected in 1965, according to the Center for Biological Diversity.
According to the petition for ESA protection, "newts in Crater Lake are morphologically, genetically and physiologically distinct from populations of newts outside of the lake."
Their crayfish predators currently occupy up to 95% of the lake’s shoreline. Scientists estimate they will occupy all of the shoreline in as little as two years.
Stewart-Fusek said the loss of the newt could predict future problems for the national park.
"Amphibians are a canary in a coal mine pretty classically in terms of ecosystem function. So we're seeing this species go extinct before our eyes. Up to 95% of them have been lost, it appears, based on crayfish expansion in 95% of the lake," she said.
The growth of the crayfish also threatens Crater Lake’s famous clarity; they eat the lake's native invertebrates that consume plankton, thereby increasing algae growth in the lake.
If protection for the newt is granted under the ESA, that would mean more funding for crayfish removal efforts and the development of a comprehensive recovery plan for the newt.
The U.S. Fish and Wildlife Service has 90 days to respond with an indication of whether the news might warrant a listing under ESA. The Center for Biological Diversity has requested that the petition be considered on an emergency basis "due to the imminent threat that introduced crayfish pose to the newt’s continued existence."
"It's kind of a perfect example, what we're seeing with the Crater Lake newt, of how quickly things deteriorate as a result of short-sighted actions by us humans and of what happens when existing human-caused threats are exacerbated by the effects of climate change," Stewart-Fusek said.
