Nevada Area Report

Authors: Eric S. Miskow, Darrick S. Weissenfluh, Jeff Peterson, Karie A. Wright, Chad Mellison, David J. Syzdek, Krissy W. Wilson, Shawn C. Goodchild

Year: 2011 (xliii)

Abstract

A summary, overview and status of Nevada’s desert fishes, current research and management projects in the state are addressed. Nevada waters contain 16 endangered and 6 threatened species of fishes as well as numerous undescribed taxa. In southern Nevada ongoing habitat modifications and restoration projects in the Muddy River Warm Springs complex continue to increase suitable habitat for the endangered Moapa dace, Moapa coriacea in addition, semi- annual dace counts reveal that there has been a 54% increase in the population since the 2008 February low. An additional rotenone treatment is scheduled for late 2011 to further reduce the invasive blue tilapia, Oreochromis aureus. In far eastern Nevada, remnant populations of the relict dace, Relictus solitarius, are being genetically analyzed in preparation for a rehab project eliminating several ponds creating more stream-like habitat in the southern portion of the Ruby Valley National Wildlife Refuge. The creation of more suitable habitat as well as a rotenone application for removal of non-natives and relict dace/speckled dace, Rhinichthys osculus ssp. hybrids is scheduled for early autumn. Habitat for the undescribed Wall Canyon sucker, Catostomus sp. in northeastern Nevada is receiving funding from the Desert Fish Habitat Partnership to work toward the design and construction of a barrier site on Mt. View Creek, a tributary of Wall Canyon Creek. Non-native brown trout, Salmo trutta as well as signal crayfish, Pacifastacus leniusculus , continue to heavily impact the Wall Canyon sucker. One of the two remaining pluvial lakes from ancient Lake Lahontan is Walker Lake, sister lake to Pyramid Lake. Upstream water diversions of the Walker River began in the early 1900’s, since this time the lakes surface level has dropped by over 150 feet. Salinity levels have increased to a lethal level for all native fishes of over 19,000 mg/L. This has decimated the fishery to the extent that the native Lahontan tui chubs, Siphateles bicolor pectinifer and S. b. obesa have failed to spawn, further compromising the fishery. A refugium was constructed at Rose Creek Reservoir in the Walker Lake basin in hopes of maintaining a viable population of Lahontan tui chub until further water appropriations and management actions by the Walker Lake Fisheries Improvement Team can be met. The restoration of North and South Indian springs in Ash Meadows National Wildlife Refuge began in 2009 and was completed in Spring 2011. Post-restoration effectiveness monitoring indicates red swamp crayfish, Procambarus clarkii , and western mosquitofish, Gambusia affinis, were successfully eradicated during the project. Endangered Warm Springs pupfish, Cyprinodon nevadensis pectoralis , have been reintroduced and monitoring has confirmed the population has more than doubled from its pre-restoration numbers. Additionally, four endemic aquatic invertebrates, all of which were extirpated prior to restoration activities (most likely by P. clarkii), have been recently repatriated. The Upper Carson Slough (UCS) includes Fairbanks, Soda, Rogers, Longstreet, Five, and Cold springs and is located downstream of a 385 square-mile drainage basin. Restoration of the Fairbanks (Phase 1) and Soda springs streams was completed in 2010. Phase 2 of the Fairbanks Spring stream restoration was completed in Spring 2011. Post-restoration monitoring indicates the population of endangered Ash Meadows speckled dace, Rhinichthys osculus nevadensis , introduced into the restored Phase 1 Fairbanks Spring stream in 2010, is stable and has expanded its range into the Phase 2 stream. The endangered Ash Meadows Amargosa pupfish, Cyprinodon nevadensis mionectes , is thriving throughout the restored outflow channel and the endemic Fairbanks springsnail, Pyrgulopsis fairbanksensis, has a slightly expanded range in the Fairbanks stream. The outflow streams of Rogers and Longstreet springs connect to the Fairbanks stream. The only population of non-native sailfin molly, Poecilia latipinna , occurring in the UCS was in Longstreet Spring and its outflow; that population was successfully eradicated in February 2011. In addition to these species updates, restoration efforts in Railroad Valley for the Threatened Railroad Valley springfish, Crenichthys nevadae, and the Endangered Clover Valley speckled dace, Rhinichthys osculus oligoporus will be discussed.