Population ecology of the mottled sculpin, Cottus bairdii, in a desert creek system

Authors: Aaron Ambos

Year: 2012 (xliv)

Abstract

Cottus bairdii is a widespread sculpin species that occurs across much of the U.S. and into southern Canada. Although absent from most of the desert southwest, its distribution does include creek systems within the Great Basin Desert in eastern Nevada and western Utah. Big Springs Creek/Lake Creek is a spring fed creek system that flows for approximately 16 miles in Snake Valley (White Pine Co., Nevada, and Millard Co., Utah), and terminates in Preuss Reservoir. This creek system maintains a native fish fauna comprised of redside shiner (Richardsonius balteatus), speckled dace (Rhinichthys osculus), Utah chub (Gila atraria), Utah sucker (Catostomus ardens), and mottled sculpin (C. bairdii). As part of a biological monitoring program in 2009-2011, an annual three-pass depletion survey was conducted along four to six 100-meter reaches, spaced along the entire system. Each 100 m reach was isolated from the system using block-nets, and three passes were made with a Smith-Root LR-24 Electrofisher. C. bairdii was only detected on the same single reach at a location of spring inflows during each annual sampling effort. In 2009, 89 C. bairdii were recorded with a catch rate of 3.5 fish/minute. An apparent increasing population trend was shown in 2010 and 2011 with a recorded 295 individuals (catch rate of 16.1 fish/minute) and 766 individuals (catch rate of 17.8 fish/ minute) respectively. By 2011, although C. bairdii had the most limited distribution in the system, it was the most abundant fish species in the reach of occurrence. Fish length frequency was similar in 2009-2011 and mean length for the three years was 50.4mm, 52.5mm, and 52.1mm respectively.