Distribution of Fishes and Fish Assemblages in the Northern Owens Valley

Authors: Nicholas Buckmaster, Rosa Cox, Leah Botelho, Christi Kruse, Steve Parmenter

Year: 2018

Abstract

Here we report the results of over 100 kilometers of electrofishing stream surveys to assess the distributions of Owens Valley fishes, including Owens Sucker (Catostomus fumeiventris), and Owens Speckled Dace (Rhinichthys osculus sp.). Surveys were conducted in valley-bottom streams and ditches from Round Valley (north of Bishop, CA) to Tinnemaha Reservoir (south of Big Pine, CA). Hierarchical clustering was used to identify five species assemblages comprised of native+nonnative, and wholly nonnative, fish communities. Fish assemblages were compared with water quality, geomorphic, and land-use data to better understand species distribution within the watershed. Comparing the historic site record with the current distribution survey, we conclude the two native species remain widespread. However, Owens Speckled Dace appear to have undergone a substantial range contraction, whereas Owens Sucker distribution has remained stable. The persistence of Owens Suckers is likely due to the presence of large adults which exceed the gape-limit of sympatric, co-occurring brown trout.