White River Spinedace Seasonal Survival & Movement in Flag Spring, Nevada

Authors: Summer Burdick, Mark Beckstrand, James Harter, Rachael Paul-Wilson

Year: 2022

Abstract

White River spinedace were common in seven springs in Nevada’s White River Valley in the late 1940s but since then their distribution and abundance declined due to hydrologic alterations and introduced species. By 1991 the only known White River spinedace in existence were 37 large and presumably old fish in the upper most 70 m reach of the north fork of Flag Spring. To prevent their extinction, largemouth bass were eradicated from a 3 km section of the Flag Springs complex and 20 White River spinedace were moved 200 m to downstream lotic habitat. These fish reproduced and the species is now distributed throughout the Flag Springs complex. A second reintroduction into Indian Spring was attempted but spinedace failed to reproduce. Before attempting another conservation introduction, information is needed on spawning behavior and habitats, and adult survival. Spinedace were captured in minnow traps and PIT tagged on four semi-annual occasions from November 2020 to June 2022. These fish were redetected during subsequent capture events and on antennas installed throughout the Flag Springs complex. Both physical recaptures and remote detections of tagged fish were used to estimate survival using a Barker Model. While spinedace were distributed throughout the complex, they were concentrated in cooler water habitats in the north and middle forks of Flag Springs and in upper Sunnyside Creek and avoided the warmer south Flag Spring. White River spinedace did not exhibit seasonal movements indicative of spawning. The probability of recapture was 0.36 (CI=0.21-0.54) and the probability of remote redetection was ≥ 92%. Semi-annual survival of White River spinedace >70 mm standard length, was 0.41 (CI= 0.30-0.53).