Biologists have not counted the number of endangered Devils Hole pupfish in nearly two years because of the pandemic.
But there’s promising news: the number of eggs observed indicates the population should be doing relatively well.
As of last count, only about 170 pupfish existed at Devils Hole, their only natural habitat. So every egg that hatches is a victory.
In February and March, biologists collected more eggs than ever before, said U.S. Fish and Wildlife Service biologist Jenny Gumm.
In September, divers will return to Devils Hole to count the actual fish population. They normally do a count twice a year but have been unable to share air on their scuba dive surveys because of the coronavirus.
The Devils Hole pupfish will always be endangered, and it has long known adversity. A species evolved in an extreme environment in Nevada’s corner of Death Valley National Park, the pupfish has been endangered for 54 years.
Though the wild population remains below historic levels, efforts to shore up the population are making progress.
“Devils Hole is still under the influence of human impacts,” said Kevin Wilson, an aquatic ecologist with the National Park Service. “I think, as a society, we have an obligation to try to prevent such things as extinction from happening.”
Devils Hole is a geothermal pool within a limestone cave. It is surrounded by an observation deck, fencing topped with barbed wire, locked gates and cameras trained on the narrow slot in the limestone that is a portal to an underwater world that hasn't been fully mapped.
It is here and only here where the Devils Hole pupfish live in the wild. The turquoise water has a low dissolved oxygen level and a temperature of about 94 degrees.
The pupfish population in Devils Hole hit a low of 35 in 2013. A normal, though tiny, population would be about 200. It hasn’t been that in about 20 years.
Most pupfish are now born in the U.S. Fish and Wildlife Service’s Ash Meadows Fish Conservation Facility with the hopes of revitalizing the wild population. They are bred in an elaborate complex of tanks, including a massive “refuge tank” built to mimic Devils Hole.
Scientists at the facility in Amargosa Valley can experiment without impacting the fragile natural environment, tweaking conditions to see what might help the wild fish thrive.
At roughly 540 square feet, the fish’s native range is the smallest of any vertebrate. Although the depths of the caverns are unknown, much of the fish’s activity is confined to a rock shelf just beneath the surface, where they spawn and feed on algae.
Biologists place carpeted mats on the shelf a few days a month to collect eggs that can be hatched in tanks. The captive fish, smaller than most guppies, are a backup population should there be a catastrophic die-off of the wild pupfish.
The fish's highly educated and specialized servants go to great lengths to keep the tiny animals alive. "But they're a pretty special fish,” said Gumm, who manages the conservation facility.
Outside of the tanks, the fish will only ever be able to live in their sliver of Devils Hole, and “the habitat’s never going to grow,” Wilson said. “It’s only going to decline.”
For what the fish lack in size, range and numbers, they more than make up for in cultural, legal and ecological presence.
President Harry Truman added Devils Hole and the 40 acres around it to then-Death Valley National Monument in 1952, in part because of the pupfish.
The fish made the first federal list of imperiled species in 1967 under the Endangered Species Preservation Act, the precursor to the Endangered Species Act.
In 1976, the U.S. Supreme Court required ranchers and farmers to stop drawing down the water table just outside the boundaries of Truman’s addition. This was the era of “Save the Pupfish” and “Kill the Pupfish” bumper stickers in the area. Wilson said competing attitudes about the fish linger in Pahrump, where he keeps his office.