Biologists worry about sharp drop in numbers of Moapa dace

The Moapa dace has spent more than 40 years on the endangered species list. Its entire habitat has been in the protective custody of the federal government and the Southern Nevada Water Authority since 2007.

So where have all the fish gone?

Two years ago, biologists counted 1,172 dace in the spring pools and streams at the headwaters of the Muddy River, 60 miles north of Las Vegas. A count last week revealed a population of just 462, prompting fears of extinction for the tiny fish found nowhere else in the world.

No definitive cause for the decline has been determined, but one federal official said recent efforts to protect the fish might have killed them instead.

Restoration crews have been rebuilding stream channels and tearing out non-native vegetation, including some of the imported palm trees that now surround the Warm Springs area where dace are concentrated. That work may have disrupted the dace’s spawning and forced the fish into areas where they can’t thrive.

"These are short-term impacts for long-term gains," said Bob Williams, state supervisor for the U.S. Fish and Wildlife Service. "We believe with the restoration the numbers will rebound."

The real decline came sometime in 2007, when more than 60 percent of the population was lost, leading to a count last February of 459 dace.

Until then, the population had never been known to fall below 900.

In 1994, the area was home to some 3,825 dace, at least until a fire in the palm groves that summer dropped smoldering fronds into the water and wiped out about half the population.

When the recent drop in population was discovered last year, it triggered a review of the habitat restoration work. Officials also decided to begin counting the fish twice a year instead of once.

But some are not so quick to blame the restoration effort.

Janet Monaco, who heads the water authority’s Muddy and Virgin River Division, said it is unclear what caused so many dace to disappear in such a short time.

"I would say we don’t know. We don’t know, but the good news is we’ve had three counts where the number has held steady," Monaco said.

The counts Monaco is referring to are the ones from February 2008, August 2008 and last week, all of which peg the population at between 459 and 462 fish. That suggests something happened to the dace, but it isn’t happening anymore, Monaco said.

The counts aren’t exact, but they are about as thorough and accurate as conditions allow, said Cailin Doyle, a biologist for the water authority.

She should know. She was part of the team that fanned out across the refuge and surrounding property late last week to count fish in two-person teams, one person facedown in the water and the other on shore with a clipboard.

Doyle was the one who got wet. In some places, she had to crawl through water barely deep enough to get her snorkeling mask halfway under the surface. In others, she had to scramble over sunken logs and search for dace among thick clumps of plants. It took her about four hours to cover less than a half mile of stream.

"You have to get into all of the nooks and crannies to count these fish," she said.

Williams said no study has been done to determine the minimum number of Moapa dace needed for the species to remain genetically viable.

This much is for sure: Those in charge of protecting these fish have only one chance to get it right. Unlike other protected species of desert fish, there is no backup population of dace being kept in a secluded tank somewhere, Williams said.

Efforts to breed dace in captivity have failed because the fish needs specific conditions that are hard to duplicate, namely a flowing stream ranging in temperature from about 90 degrees for larval fish to the low 80s preferred by the finger-length adults.

The dace’s natural habitat is confined within the 117-acre Moapa Valley National Wildlife Refuge and the neighboring Warm Springs Natural Area, a 2,000-acre tract the water authority acquired in September 2007.

The primary threats to the dace are habitat loss and the invasion of tilapia, a non-native game fish that found its way up the Muddy River from Lake Mead in the early 1990s. Tilapia are known to eat both the dace and their food.

"It’s a competitor in every sense of the word," Williams said.

Beavers also have posed a problem over the past year. Two of the tenacious dam builders had to be trapped and killed in recent months to halt the destruction of stream habitat.

The Moapa dace is expected to remain under federal protection until at least 75 percent of its historical habitat has been restored and its population is holding steady — at least 6,000 adult fish.

Williams is confident the situation will improve.

"Conditions out there are better now than they were last year. We would hope to see the numbers up a couple hundred" by the next year’s February count, he said. "We want this to be the low point."

Others are not optimistic.

Two days before the start of last week’s annual fish count, the Tucson, Ariz.-based Center for Biological Diversity announced plans to sue the federal government over its protection of the dace.

The latest numbers only bolster the center’s warnings against large-scale groundwater pumping planned in the area by the water authority and others, said Randy Serraglio, conservation advocate for the environmental group.

If the dace are this vulnerable before the pumps are even turned on, he said, "the proposed development could be the death knell for the species."

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

ad-high_impact_4
News
Melvin Dummar dead at 74
Melvin Dummar has died at 74. Dummar was famous for claiming to have saved Howard Hughes in a Nevada desert in 1967. Dummar claimed to have been left $156 million in Hughes’ will. The will mysteriously appeared after Hughes’ death in 1976. It was dismissed as a fake two years later. Dummar never saw a dime of the billionaire's fortune. Dummar died Saturday in Nye County.
Officer-involved shooting in Nye County
The Nye County Sheriff's Office gives information about a shooting in Pahrump on Thursday night after a man began firing shots outside of his home. (Nye County Sheriff's Office)
Law Enforcement Active Shooter Training Exercise
Multiple Las Vegas Valley law enforcement agencies held an active shooter drill at the Department of Public Safety’s Parole and Probation office on December 6, 2018. Officials set up the training exercise to include multiple active shooters, a barricaded suspect and multiple casualties. (Katelyn Newberg/ Las Vegas Review-Journal)
Public memorial service for Jerry Herbst
Archiving effort hits milestone at Clark County Museum
The Clark County Museum catalogs the final item from the bulk of Route 91 Harvest festival artifacts. (John Przybys/Las Vegas Review-Journal)
Pearl Harbor survivor Edward Hall talks about his memories of Dec. 7, 1941
U.S. Army Corps Edward Hall, a 95-year-old survivor of Pearl Harbor talks about his memories of that horrific day. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Final Route 91 Harvest festival remembrance objects catalogued at Clark County Museum
The last of the more than 17,000 items left at the makeshift memorial near the Las Vegas sign after the Oct. 1 shootings have been catalogued at the Clark County Museum in Las Vegas. The final item was a black-and-white bumper sticker bearing "#VEGASSTRONG. An additional 200 items currently on display at the museum will be catalogued when the exhibit comes down. (K.M. Cannon Las Vegas Review-Journal)
Dozier execution timeline
Scott Dozier was set to be executed July 11, 2018, at the Ely State Prison. Judge Elizabeth Gonzalez delayed the execution.
Grand Jury Indicts Constable for theft
A Clark County grand jury indicted Henderson Constable Earl Mitchell. A Las Vegas Review-Journal investigation prompted the criminal probe. The newspaper found Mitchell wrote himself thousands in checks, took out cash at ATMs and traveled on county funds. He faces four felony counts of theft and a county of public misconduct. Mitchell and his attorney could not be reached for comment.
93-year-old WWII veteran arrested during visit to VA hospital
Dr. S. Jay Hazan, 93, a World War II veteran, talks about his arrest during his visit to VA hospital on Friday, Nov. 30. (Erik Verduzco Las Vegas Review-Journal @Erik_Verduzco_
Pearl Harbor survivor struggles in her senior years
Winifred Kamen, 77, survived the attack on Pearl Harbor as an infant, works a 100 percent commission telemarketing job to make ends meet. (K.M. Cannon Las Vegas Review-Journal)
Las Vegas Metropolitan Briefing 18th street gang
Las Vegas Metropolitan briefs the media on the recent arrests made regarding the 18th street gang.
Man shot in Las Vegas traffic stop had knife, police say
Police said the man fatally shot by an officer during a traffic stop in downtown Las Vegas had a “homemade knife.” Demontry Floytra Boyd, 43, died Saturday at University Medical Center from multiple gunshot wounds after officer Paul Bruning, 48, shot him during a traffic stop. Bruning pulled Boyd over on suspicion of driving recklessly at 7:41 a.m. near Sunrise Avenue and 18th Street.
Catahoula dogs rescued from home in Moapa Valley
Catahoula dogs were brought to The Animal Foundation after being rescued from home in Moapa Valley.
Intuitive Forager Kerry Clasby talks about losses in California wildfire
Intuitive Forager Kerry Clasby talks about losses she suffered in California's Woolsey Fire in Malibu in November. (Al Mancini/Las Vegas Review-Journal)
Benefit dinner for Kerry Clasby, the Intuitive Forager
Sonia El-Nawal of Rooster Boy Cafe in Las Vegas talks about having a benefit for Kerry Clasby, known as the Intuitive Forager, who suffered losses on her farm in California’s Woolsey Fire in Malibu. (Al Mancini/Las Vegas Review-Journal)
Former President George H.W. Bush dies at 94
Former President George H.W. Bush has died at the age of 94. He died Friday night in Houston, about eight months after the death of his wife, Barbara.
Las Vegans Celebrate Big Snowfall
Las Vegans celebrate big snowfall at Lee Canyon.
Exploring old mines for denim jeans and other vintage items
Caden Gould of Genoa, Nev. talks about his experiences looking for vintage denim jeans and other items in old mines and other places areas across Nevada and the west.
Officers share photo of dead gunman after Las Vegas shooting
A little over an hour after SWAT officers entered Stephen Paddock's suite at Mandalay Bay, Las Vegas police officers far from the scene were already sharing cell phone photos of the dead Oct. 1 gunman.
Frontier jet safely returns to Las Vegas after losing engine piece
Frontier jet safely returns to Las Vegas after losing engine piece. (@FlightAlerts_)
Park Service plans ahead for lower lake levels
National Park Service releases new plans to maintain access to the water as Lake Mead continues to shrink.
Women claim abuse at Florence McClure Women's Correctional Facility
Current and ex-inmates, including Merry West, are suing Florence McClure Women’s Correctional Facility, claiming abuse and inadequate medical care. (Rachel Aston/Las Vegas Review-Journal) @rookie__rae
Butte County Sheriff's Office Body Cam Footage
Bodycam video from Butte County (Calif.) Sheriff's Office Deputy Aaron Parmley, who was in Paradise November 8 helping with evacuations. (Butte County Sheriff's Office)
NDOT construction blasting along State Route 106
NDOT construction blasting along State Route 160, near Mt. Potosi Road, in Clark County as part of a $59 million, 6-mile-long highway widening project that began this summer. (Nevada Department of Transportation)
Car crashes into Papa Murphy's Pizza shop
A driver crashed a car into a western Las Vegas Valley pizza shop on Tuesday morning, police said. (Joe Stanhibel/Special to Las Vegas Review-Journal)
Low-lake-level pumping station nears completion
Barnard Construction and the Southern Nevada Water Authority give one last tour before the new low-lake-level pumping station is activated.
Trailer: Valley of Fires
Sultan’s Playroom from Make-A-Wish Southern Nevada
Make-A-Wish Southern Nevada’s Scott Rosenzweig talks about granting Sultan Bouras Souissi’s wish, and what went into building it. (John Hornberg/Las Vegas Review-Journal)
Jim Marsh brings historic replica of rural church to Amargosa Valley
Jim Marsh talks during the opening of the Chapel at Longstreet, a replica of an 1874 Catholic church built in the mining town of Belmont, Nev., at Marsh's Longstreet Casino in Amargosa Valley, Nev. Chase Stevens/ Las Vegas Review-Journal
TOP NEWS
News Headlines
Add Event
Home Front Page Footer Listing
Circular
You May Like

You May Like