Spawning ecology of the critically endangered Moapa dace, Moapa coriacea, revealed through underwater videography

Authors: Jack E. Ruggirello, Scott A. Bonar, Olin G. Feuerbacher

Year: 2012 (xliv)

Abstract

Moapa dace, Moapa coriacea, are a critically endangered cyprinid endemic to the Warm Springs area of Clark County, Nevada. Because of its limited range, low abundance, and impacts from introduced species, Moapa dace were federally listed as an endangered species within thirty years of being described. The spawning ecology, a portion of Moapa dace life history that is crucial to comprehend for its recovery, is not fully understood. We installed twelve underwater cameras, one every ten meters, in the uppermost reach of Plummer Stream. Cameras were equipped with infrared light to record both day and night activity. Camera sites were randomly selected to represent a variety of habitat-types (i.e. pools, glides, runs, and riffles). We quantified available habitat by dividing the field of view in front of each camera into a grid to measure size and embeddedness of substrate, depth, stream velocity, and categorize cover. We recorded approximately 21,000 hours of video from March through May 2012. We randomly selected sixteen 10-minute video clips in every 24-hour period, from each camera, to analyze for spawning activity. Based on activity reviewed to date, Moapa dace appear to be broadcast spawners. Spawning events were recorded in three sites; one in a run, four in a glide, and five in a pool. Three spawning events occurred between 7:50am to 9:00am and seven between 2:10pm and 6:40pm. Further knowledge of the spawning ecology of Moapa dace will be important for identifying factors that induce spawning in captivity and will provide crucial data for managers to utilize in habitat improvement projects.