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US Fish & Wildlife Service FieldNotes

MOAPA VALLEY NWR: Endangered Moapa Dace Experience Healthy Population Jump

Region 8, September 17, 2012
The endangered Moapa dace
The endangered Moapa dace - Photo Credit: n/a
Jack Ruggirello, a graduate student at the University of Arizona, snorkels in a shallow reach of the Muddy River system to count the Moapa dace living on the Moapa Valley National Wildlife Refuge.
Jack Ruggirello, a graduate student at the University of Arizona, snorkels in a shallow reach of the Muddy River system to count the Moapa dace living on the Moapa Valley National Wildlife Refuge. - Photo Credit: n/a

By Dan Balduini, Public Affairs

Expanded habitat, eradication of invasive species gives endangered fish a fighting chance.

The continued efforts of the U.S. Fish and Wildlife Service (Service) and its partners appear to be benefitting the Moapa dace, an endangered fish found only in the Warm Springs area of the Moapa Valley in southern Nevada.

Biologists conducted a snorkel survey in the Muddy River system during the first week of August 2012, and counted 1,181 Moapa dace. The count represents an increase of 65 percent over the number of dace found a year earlier in August 2011, when 713 fish were found. This is the first time since February 2007 that the Moapa dace population has topped 1,000 fish.

“This milestone could not have been reached without the focus and coordinated efforts of everyone involved,” said the Service’s state supervisor Ted Koch. “Our staff and all of our partners in this effort should be proud of this accomplishment.”

The Service’s partners — the Bureau of Land Management, Nevada Department of Wildlife (NDOW), Southern Nevada Water Authority (SNWA), U.S. Geological Survey (USGS), Moapa Band of Paiutes, Moapa Valley Water District, Clark County Desert Conservation Program, the Nature Conservancy, NVEnergy, Coyote Springs LLC, and local landowners — have expanded efforts in recent years to protect and restore habitat for the native aquatic species in the upper Muddy River system, while also controlling threats from non-native species.

“The Southern Nevada Water Authority is very pleased with the strides being made in restoring this habitat,” said Robert Johnson, SNWA land manager for the Warm Springs Natural Area. “It is rewarding to see that our efforts—and the efforts of the partnering agencies—are providing measurable contributions toward preserving the Moapa dace.”

The Moapa dace is endemic to the thermal springs and streams that form the headwaters of the Muddy River (which eventually joins the Colorado River at Lake Mead). The Warm Springs area, which includes the 116-acre Moapa Valley National Wildlife Refuge, is home to other endemic aquatic species including the Moapa White River springfish and numerous invertebrates such as springsnails, water bugs, and riffle beetles. The Moapa Valley NWR is part of the Service’s Desert National Wildlife Refuge Complex.

“Because Service staff had restored habitat on the wildlife refuge, most of the dace in the system have generally been found there,” said Shaun Sanchez, manager of the Desert NWRC. “Obviously, the additional restored habitat off of the refuge and the elimination of non-native competitor and predatory fish gives the dace more of a fighting chance.”

In the mid-1990s, non-native mollies and blue tilapia decimated the Moapa dace population and other native fish in the Muddy River. NDOW leads the effort to eliminate the non-native species.

“Controlling the exotic fish is time-consuming, costly, and challenging,” said Jon Sjöberg, NDOW’s supervising fisheries biologist. “We are pleased that the increased control efforts appear to be showing promise.”

“While we celebrate the nearly 1,200 endangered dace now in the Moapa Valley, we remain cautiously optimistic about the long-term outlook for the Moapa dace, Koch said. We know that recovery of the species is still a long way off.”

Located at 4001 W. Warm Springs Road in Moapa, the Moapa Valley NWR was the first wildlife refuge established specifically for an endangered fish. The refuge was established in 1979 to secure habitat for and protect the endangered Moapa dace. In addition to spring and channel restoration efforts, re-vegetation with native plants, removing non-native species, and enhancing stream flows have benefited the Moapa dace and the White River springfish, as well as other endemic (native) species at the wildlife refuge. For more information about the Moapa Valley NWR, visit the refuge website or contact Refuge Manager Amy LaVoie via email at amy_lavoie@fws.gov or by telephone at (702) 515-5225.

Contact Info: Dan Balduini, 702-515-5450, daniel_balduini@fws.gov