Strong earthquakes like the one felt in Northern California last week are a stark reminder for people to plan. Perhaps it’s to fortify your home or business, or at least eventually build an earthquake kit.
But for the Devil’s Hole pug, an endangered species that lives only in Death Valley’s deep limestone caves, the earthquake signals it’s time for something a little more intimate.
Scientists say the fish’s response to the magnitude 7.0 earthquake that shook a wide area from San Francisco to Reno to southern Oregon was likely to increase spawning activity to protect the population. . This is a phenomenon that has occurred in several earthquakes in the past.
About two minutes after the quake, water began flowing in Devil’s Hole, about 500 miles from the epicenter. Scientists estimate that the waves, known as seiches, were about 2 feet high. In a typical stillwater environment, waves could have destroyed the shallow ledges that pugs use as spawning grounds, knocking the eggs deep into the cave.
“We’ve seen in the past that fish have evolved to respond by spawning more eggs after a flood or an earthquake,” said National Park Service biologist Kevin Wilson. “Think of it like, ‘Oh, no, there’s been a drastic change in my home, my place of residence.’ I better try to have more kids.”
Scientists say this reaction is not irrational.
In 1967, pugfish were first listed as an endangered species in the United States. Until the mid-1990s, scientists counted 200 to 250 Devil’s Hole pugs each spring. But over the past 20 years, the fish’s population has declined to an average of about 90 fish, hitting an all-time low of 35 fish in 2013.
However, recently their numbers have increased in the spring and fall. Scientists found 191 pugs in April, the highest spring count since 1999. In September, 212 fish were swimming around Devil’s Hole.
In the short term, Wilson says, earthquakes aren’t good for pugs. Waves push algae that grow on the limestone ledges and small invertebrates that fish eat deep into the cave. Probably too deep for small swimmers. But there are long-term benefits, he says. The waves remove decaying organic matter that can cause hypoxia, which can be fatal to pufffish eggs.
Wilson, who has spent years studying pugs, said scientists can learn a lot about the effects of issues such as climate change from Devil’s Hole and its small fish.
“I like to call Devil’s Hole kind of a canary in the coal mine, or a bellwether,” Wilson said. “Knowing the changes we are currently detecting in response to climate change and rising atmospheric temperatures and how that is impacting this ecosystem will help us reduce it to other warming forces in the future. It can also be applied to ecosystems.”
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