The endangered yet ruthlessly resilient Devils Hole Pupfish that live in Death Valley National Park just had quite a shock. The water-filled cavern that they call home shook due to a powerful earthquake centered about 500 miles away. The 7.0 magnitude earthquake struck off the coast of Northern California on December 5. Their small aquatic habitat started shaking only two minutes later. Scientists estimate that the waves–called a seiche–were closely two feet high.
The water in Devils Hole is typically still. The pool is sheltered from wind and is at the bottom of a collapsed cave. According to the National Park Service, the unusual waves disrupted the shallow shelf that is the Devils Hole Pupfish’s main spawning area. Most of the organic matter from the shelf was moved into the over 500 feet deep cavern.
“In the short term, this is bad for the pupfish,” National Park Service biologist Kevin Wilson said in a statement. “A lot of pupfish food just sank deeper into the cave, most likely too deep for the fish to get to it. There were likely pupfish eggs on the shelf that were destroyed. But, in the long term, this type of reset is good for the pupfish. It cleaned off any decaying organic matter that could otherwise cause pockets of low oxygen.”
[ Related: Devils Hole pupfish are clawing their way back from the brink of extinction. ]
Devils Hole Pupfish are considered critically endangered by virtue of the hellish environment they call home. The pupfish are now only found in the upper 80 feet of the cave in Death Valley on an 11-foot by 16-foot shallow shelf in the cavern’s entrance. Despite being a desert, this region was underwater about 542 to 251 million years ago. Those waters receded over time and the pupfish have lived in this area for at least 10,000 years.
Devils Hole pupfish also live in the smallest habitat of any vertebrate species on Earth. The water is about 93 degrees Fahrenheit all year, has scarce food resources, and oxygen levels that would kill other fish. A 2022 study found that the Devils Hole pupfish is also one of Earth’s most inbred species. This lack of genetic variation makes it difficult for them to reproduce and thrive.
Pupfish have survived other wave events like this most recently in 2018, 2019, and 2022. In the past, they reacted to these disturbances by increasing their spawning activity. The most recent surveys counted 191 fish in April–the highest number in 25 years–and 212 fish in September.
Wilson said the team are not taking any chances with their response since this pupfish species has no other natural habitat. Biologists from the National Park Service, U.S. Fish and Wildlife Service, and Nevada Department of Wildlife are currently evaluating how to mitigate the disruption on the fish, who are also impacted by climate change and groundwater pumping. This plan will likely involve increasing the amount of supplemental food given to the fish.
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