Endangered fish Moapa dace making gains

It's been a slow struggle against the current, but the Moapa dace continues to swim away from the edge of extinction.

Clark County's most protected fish is gradually increasing in number, according to the latest count by the U.S. Fish and Wildlife Service and its partners.

A so-called "snorkel survey" earlier this month counted 713 of the finger-length spring fish. That is just 16 more than last year, but it continues an upward trend that has seen the population grow by 54 percent since an unexplained die-off in 2007.

"This is cautiously good news," said Amy LaVoie, who manages Moapa National Wildlife Refuge for the Fish and Wildlife Service. "While we're making progress, there's still a long way to go."

The Moapa dace lives in the springs and streams that form the Muddy River, 60 miles north of Las Vegas. The endangered fish is found nowhere else in the world, and efforts to raise it in captivity have been unsuccessful.

The dace has been under federal protection for more than 40 years. It is expected to remain on the endangered species list until at least 75 percent of its historical habitat has been restored and its population is holding steady at 6,000 adult fish.

Biologists were worried about a drop in population after a July 1, 2010, wildfire swept through the area. So far, though, the dace appears to have escaped the blaze unscathed.

Fish and Wildlife Service spokesman Dan Balduini said it is obvious why. Counts conducted in February and earlier this month showed high concentrations of fish in areas where workers have restored the streams to a more natural state.

Those areas, mostly on the 117-acre Moapa National Wildlife Refuge, provided safe haven for the fish when the fire broke out, Balduini said.

"It's obvious they're very strong swimmers. I'm grateful they had somewhere to go," he said. "They knew where to go, and they found it."

More than half the fish spotted during the latest count were located on the wildlife refuge. The rest populate streams on some adjacent private land and at the Warm Springs Natural Area, a 1,218-acre tract the Southern Nevada Water Authority bought in 2007 for $69 million.

The wholesale water supplier for the Las Vegas Valley agreed to become a chief defender of the dace under a 2006 federal agreement that cleared the authority to pump groundwater at nearby Coyote Springs.

The fish can use all the help it can get.

A count in early 1994 showed a population of 3,825 dace. Then a fire in the palm groves that summer dropped smoldering fronds into the water and wiped out about half the population.

The species was also pushed to the brink by an invasion of tilapia, a non-native game fish that found its way up the Muddy River in the 1990s to feed on both the dace and their food.

Then came one of the largest and most alarming declines: Sometime in 2007 -- and for reasons experts still can't pinpoint -- the numbers plummeted from 1,172 to 459.

LaVoie said efforts since then to eliminate tilapia and restore stream habitat seem to have stabilized and improved the population.

The fish are surveyed twice a year by biologists swimming facedown in the shallow headwaters of the Muddy River. The February counts are lower than the August ones because the dace does a lot of its spawning in the spring, but both sets of numbers have risen consistently since 2008.

Even so, recent efforts to preserve the dace have drawn criticism from neighboring residents, especially when it came to cutting down hundreds of palm trees that give the area the feel of a desert oasis.

Water authority officials insist they are done clear-cutting palm trees and are in the early stages of developing some trails and interpretive signs so they can start opening parts of the Warm Springs Natural Area to the public.

At Moapa National Wildlife Refuge, meanwhile, LaVoie and her small but dedicated team of volunteers are preparing to open the gates to visitors starting Sept. 2.

The refuge, which features a window where visitors can watch the dace in its natural habitat, will be open Labor Day weekend, Monday included, then from sunrise to sunset on Fridays, Saturdays and Sundays through the end of May.

Contact reporter Henry Brean at hbrean@reviewjournal.com or 702-383-0350.