August 25, 2008
Spared By Court, Desert Fish Still Struggles to Survive
By Randal C. Archibold
No doubt, it is hard to be a fish in a desert.
But, to the dismay and bafflement of scientists, the Devils Hole pupfish, a quick-darting iridescent blue minnow, are veering toward extinction.
Maybe this should not be surprising, considering their home: a hellishly hot, spring-fed pool of undetermined depth in the middle of one of the hottest places on earth. The fish, for tens of thousands of years, have lived here and only here, in an isolated patch under the administration of Death Valley National Park about 100 miles, or 160 kilometers, northwest of Las Vegas.
They have plenty of cousin pupfish in other parts of the desert, who are also endangered, but none are as bad off as the Devils Hole variety, whose loss would bring an ignoble end to a species with a celebrated and controversial history. (The Devils Hole apostrophe long fell to the quirks of government cartographers and scientists, who render both the site and fish without it.)
It was one of the original fish protected under the Endangered Species Act, and figured front and center in a 1976 landmark water rights case before the Supreme Court. The ruling curtailed groundwater pumping intended to develop farms nearby in order to save the fish's habitat.
To this day, law students come to Devils Hole, peering down at the pool through a chain-link fence that, along with electronic monitors, guards the 40-acre, or 16-hectare, site. They want to see this little fish that moved legal mountains and inspired a wave of "save the..." campaigns, with competing bumper stickers: "Save the pupfish" and "Kill the pupfish."
The pupfish once numbered about 500, dining on algae and tiny crustaceans and fulfilling a yearlong lifecycle of eating, breeding and dying. But in the past several years, biologists have detected a precipitous drop in the population, down to about 45 at last count, but it had been lower a year before that.
Nobody believes anybody is deliberately harming the fish, but finding the cause for the decline has led to some unusual evening fieldwork for a team of government biologists trying to solve the mystery. One recent night they set off under skies lighted by countless stars and a half-moon. Down the craggy rocks toward the bathtub-shaped pool, they climbed and then, flat on their stomachs on a ladder extended over the surface, they counted fish larvae, to assess the health of the population.
"I got nothing," Paul Barrett, the U.S. Fish and Wildlife Service biologist coordinating the recovery effort, called out to a colleague recording the results from a nearby boulder.
"I got nothing, too," added John Wullschleger, a National Park Service biologist on the team.
Subsequent counts turned up several larvae, but it was too soon to deliver a prognosis. Wullschleger did see an encouraging sign.
"I was psyched to see larvae that small" well past the traditional spring mating time, he said. "That means we are still getting fish reproducing in the summertime."
Scientists are also compiling a variety of data - water temperature and level, the content of the algae, the makeup of sediment washed into the pool in heavy floods - to hunt for clues.
Theories abound. Might there be some genetic anomaly at play? Is a slight rise in the air temperature, attributable to global warming, inching up the water temperature as well? Has distant groundwater pumping lowered the water table in the hole?
All of those and others are being explored.
It is delicate work. A mishap with equipment in 2004 led to the death of 80 fish.
James Deacon, a retired biologist from the University of Nevada, Las Vegas, who is considered the foremost authority on the fish, said in an interview that the fish were susceptible to even the slightest changes in the water. That is one reason scientists have not had great success in trying to breed them elsewhere.
Deacon said the water level in the hole had been dropping since the late 1990s, coinciding with a development boom in and around Las Vegas, fed partly by groundwater pumping.
Although nobody has conclusively linked the water level drop to the pumping, scientists worry that Las Vegas's plan to pump billions of gallons more out of the aquifer, a vast freshwater ocean under parts of several Western states, could further upset the ecological balance.
City officials deny that the pumping would be harmful. Suspicions remain. "When you pull down the water table, the springs feeding these pools where desert fish live dry up," said E. Paul Pister, a founder of the Desert Fishes Council, a group that studies and advocates for desert fish.
The investigation continues. As is done twice a year, in October a diver will descend into the depths of Devils Hole - it is at least 500 feet, or 150 meters, deep, but nobody has ever reached the bottom - and seek to count every fish, the only way to keep track of them.
Barrett, in the dark quiet of a break from counting larvae, took some comfort in the slight increase in the recent count, perhaps due to a feeder the scientists have installed on the rock slab near the surface where the fish congregate.
"People said, 'It's not up a lot,'" he said.
"That's true. But we may have bottomed out and stopped the decline, and in my book that's a winner."
Originally published by The New York Times Media Group.
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