Devil’s Hole pupfish: Extinction could be near, with just 35 left

What began decades ago as a fight to save the world’s most isolated fish might soon end in one of the most well-documented extinctions ever.

Only 35 Devil’s Hole pupfish are left, according to new survey results released Thursday by the U.S. Fish & Wildlife Service.

It is the lowest count ever for the tiny endangered fish, which is only found in a single water-filled cavern in Nye County, about 90 miles west of Las Vegas.

But is it the beginning of the end for the species?

“Not necessarily,” said Ted Koch, supervisor of the Fish & Wildlife Service in Nevada, “but we are very concerned. When you get this low, anything can happen and you’re in a grim situation.”

The pupfish and its habitat have been under federal protection since 1967.

The species is studied and monitored relentlessly by a team of state and federal protectors. Population counts are conducted twice a year.

The bleak spring number comes on the heels of the lowest fall count ever, just 75 adult fish.

The population peaked at 544 in the fall of 1990 but began to decline in 1996 for reasons researchers still can’t explain.

Until this year, the lowest total on record was 38 in the spring of 2006 and 2007.

“So we’ve been here once before and bounced back,” Koch said.

That time, though, the reason for the crash was well-known.

In 2004, scientists mistakenly left a container of fish traps next to Devil’s Hole, and a flash flood dumped the traps into the pool, inadvertently catching and killing roughly a quarter of the population.

Not even the experts can explain what is happening to the pupfish now.

“It sounds very, very serious,” said Jim Deacon, a longtime local biologist and founder of the environmental studies program at the University of Nevada, Las Vegas. “I used to be alarmed if (the population) ever got below a hundred.”

Deacon made his first visit to Devil’s Hole in 1961, and he used to scuba dive regularly in its thermally heated water to count the tiny fish.

In the 1970s, he testified in defense of the species during a legal fight over groundwater pumping that threatened to empty Devil’s Hole. The case ended in a landmark U.S. Supreme Court decision in favor of the fish.

Today Deacon and others worry that the population may have shrunk so low that the species is no longer genetically viable.

“I don’t know what the minimum number is likely to be,” Deacon said. “It’s possible that we’re seeing genetic meltdown.”

Or the cause could be environmental. One popular explanation is that the fish’s food and spawning beds were disturbed by flood debris in August and by several strong but distant earthquakes last year that sent water sloshing in the pool.

Koch said the Fish & Wildlife Service and its research partners are still evaluating their options and trying to come up with something to counteract the decline.

Researchers plan to keep providing supplemental food to the fish. They also may try to add more organic material to the pool to replace what was washed away by the earthquakes.

So far, efforts to raise nonhybridized Devil’s Hole pupfish in captivity have failed. With so little margin for error, Koch said researchers must approach the situation the way a medical doctor would: “First, do no harm.”

If there were more fish left, Deacon would recommend moving some of them to another location with cooler water to see whether that promotes more successful spawning. But the population is far too small to chance that now, he said.

“I wish I knew what could be done. I think it is sort of a hail Mary whatever we do.”

If the Devil’s Hole pupfish cannot be saved, it will join Florida’s Dusky seaside sparrow on the list of endangered species that have died out while under federal protection.

But Koch certainly doesn’t view that as an indictment of the Endangered Species Act or of federal management of land and wildlife as a whole. After all, the future of the pupfish has always been tenuous at best, even with human help.

“This species was living on the edge of existence when the first European settlers arrived — just a few hundred individuals in a hole in the ground,” he said.

Deacon put it another, more depressing way: Every species that has ever lived has eventually gone extinct or will someday.

“Is it this fish’s time? That’s a question that we can’t ever definitively answer,” the biologist said. “I suspect that, yeah, we have made mistakes over the years. I also suspect we’ll never know what the trigger was that caused it to go extinct if it does.”

But within that uncertainty lies reason for optimism: Perhaps the pupfish will stage a comeback after all — and for reasons that researchers don’t entirely understand.

Deacon certainly hopes so.

“There’s hope that they will be able to recover from this point,” he said. “There’s still reason to hope.”