Water Quality and Sediment Chemistry of Selected Habitats of the Mohave Tui Chub, Mojave National Preserve, California, 2018

Authors: Katherine Earp

Year: 2018

Abstract

The Mohave Tui Chub, Siphateles bicolor mohavensis, was extirpated from the Mojave River drainage in California and listed as endangered in 1970. A source population of Mohave Tui Chub exists at MC Spring in Zzyzx and has been used for several reestablishment efforts in subsequent decades. Two potential habitats within the Mojave National Preserve with perennial sources of water have been identified by the National Park Service as candidates for Mohave Tui Chub reestablishment: West Pond and Rainbow Wells Pond. West Pond, an artificial pond at Zzyzx near MC Spring, contained a population of Mohave Tui Chub which died off in 1985 due to changes in water quality. The pond was rehabilitated in the past several years through re-excavation and by pumping fresh groundwater into the pond. Rainbow Wells Pond is an abandoned excavated mine site located on Cima Dome. The bottom of the excavation intersects the water table, forming a pond. In cooperation with the National Park Service, the U.S. Geological Survey conducted a study to monitor water-quality conditions at West Pond and Rainbow Wells for one year and characterize their suitability for reestablishment of Mohave Tui Chub populations. Water quality and sediment chemistry were determined through discrete quarterly sampling. Temperature was monitored continuously with deployed loggers. Data were also collected at three existing Mohave Tui Chub habitats in Mojave National Preserve to provide further information on the range of acceptable physical and chemical conditions. Initial water quality results at West Pond indicate that the pond is favorable habitat for the Mohave Tui Chub. Initial water quality results at Rainbow Wells Pond suggest that the dissolved oxygen concentrations are lower than the long-term tolerable ranges for Mohave Tui Chub.