Lower Colorado River Area Report, November 2007-2008

Authors: Pamela J. Sponholtz, Ronald B. Kegerries, Jon C. Sjoberg, Yvette Paroz, Heidi B. Blasius, Anthony T. Robinson, Matthew E. Andersen, Lesley Fitzpatrick

Year: 2008 (xl)

Abstract

It was a productive year for projects implemented under the Central Arizona Project Funds Transfer Program (CAP) in the Lower Colorado River basin. Completion of the CAP revised biological opinion brought the fund to $550,000 annually, and extended the fund timeline from 25 to 30 years. Under this program, the Bubbling Ponds Native Fish Facility was successful at producing spikedace, (Meda fulgida) and loach minnow, (Tiaroga cobitis), in captivity and has been able to produce over 6,500 fish for various repatriation projects. Fossil Creek, renovated in 2005, was one of the highlights of 2008 and was stocked with spikedace, loach minnow, razorback sucker, (Xyrauchen texanus), longfin dace, (Agosia chrysogaster), and desert pupfish (Cyprinodon m. macularius). In the Verde River, GIS is being used to provide georeferenced databases as a foundation for the development of a watershed-scale management plan and will identify boundaries between native fish and nonnative fish management units to reduce conflicts. In Grand Canyon, an additional 299 small humpback chub (Gila cypha) were translocated above a series of falls in the Little Colorado River and the approximate population size of the Grand Canyon humpback chub population, as of 2006 (most recent date currently available) is 6,017 (95% CI 5,369-6,747). Nevada Department of Wildlife (NDOW) is continuing to see positive results from efforts to re-establish the Virgin spinedace (Lepidomeda m. mollispinis) population in upper Beaver Dam Wash, Nevada. Monitoring surveys in November 2007 and May 2008 indicate continued reproduction and successful recruitment and some expansion of Virgin spinedace into upstream habitats. The Lower Virgin River Recovery Implementation Team has implemented a pilot rotenone treatment in preparation for larger efforts designed to prevent the spread of blue tilapia (Oreochromis aureus), and eventually red shiner (Cyprinella lutrensis), to the upper Virgin River. BIO-WEST, Inc. sampled the Muddy River from the Overton Wildlife Management Area upstream to the newly erected Bureau of Land Management fish barrier to determine the distribution and abundance of native and nonnative fishes in this area. Sampling efforts resulted in the capture of 12 distinct fish species including two native species Virgin River chub (Gila seminuda), and speckled dace (Rhinichthys osculus). However, during the spring 2008 sampling event red shiners were captured further upstream than any other recorded findings. In Lake Mead, NDOW continues to rear razorback suckers at the Lake Mead Fish Hatchery cooperatively with US Bureau of Reclamation primarily using wild caught Lake Mead larvae. Arizona State University finished six years of work monitoring post-stocking fate of razorback sucker and bonytail (Gila elegans) stockings. There was no measurable long-term survival for razorback sucker, and the first year’s survival was estimated at about only 30%. Along the Lower Colorado River, stocking activities in 2008 included over 65,000 razorback sucker into Lake Mohave, and Davis Dam to Imperial Dam using fish that are reared at Willow Beach from wild caught larvae. Over 24, 000 bonytail were stocked into Davis Dam to Imperial Dam reach from fish that are produced by Dexter National Fish Hatchery and reared at Dexter, Willow Beach, and Achii Hanyo. The state of New Mexico entered the second year of angling for federally threatened Gila trout (Oncorhynchus gilae) and stocked excess hatchery trout for recreation in 2008. New Mexico Department of Game and Fish has been working with private landowners to benefit native fishes and has stocked roundtail chub (Gila robusta) into a Nature Conservancy pond and Gila topminnow (Poeciliopsis o. occidentalis) into Burro Cienega. University of Arizona is nearing completion on research aimed at methods to propagate 5 species of desert fishes and optimizing mechanical control techniques for invasive crayfish. In addition, they have begun to identify factors limiting survival of Devils Hole pupfish (Cyprinodon diabolis) larvae and research into the spawning ecology of Devils Hole pupfish. In the Little Colorado River drainage, the population levels of LC spinedace (Lepidomeda vittata ) in Nutrioso and Rudd creeks continue to fluctuate due to drought and an abundance of non-native crayfish. However, multiple age classes were found, and some areas of the creeks had large populations. In East Clear Creek, adult and YOY LC spinedace were observed in Yeager Canyon which was stocked last year using broodstock raised at the Flagstaff arboretum. Unfortunately, green sunfish (Lepomis cyanellus), largemouth bass (Micropterus salmoides) and yellow bullhead (Ameiurus natalis) were captured in Blueridge reservoir. These are new species to this drainage and could decimate already low LC spinedace populations. Arizona Game and Fish Department and the U.S. Fish and Wildlife Service augmented the Mexican stoneroller (Campostoma ornatum) population in West Turkey Creek on the El Coronado Ranch and two new populations of Apache trout (Oncorhynchus apache) were established in the White Mountains. A multi-agency native fish enhancement project was completed in Bonita Creek and included the construction of a physical barrier to prevent upstream movement of nonnative fishes, chemical removal of nonnative fish from a 1.7 mile reach, and repatriation of currently extant native fishes Gila chub (Gila intermedia), longfin dace, speckled dace, Sonora sucker (Catostomus insignis), and desert sucker (Pantosteus clarki). Contributors to this report include (in alphabetical order): Matthew Andersen, Chuck Benedict, Heidi Blasius, Scott Bonar, Chris Cantrell, Stephanie Carman, Doug Duncan, Lesley Fitzpatrick, Ron Kegerries, Brian Kesner, Jason Kline, Anne Kretschmann, Yvette Paroz, Craig Paukert, Tony Robinson, John Sjoberg, Mitch Thorson, Jeremy Voeltz, David Ward