Environmental Factors and Spawning Behavior in the Devils Hole Pupfish

The highly endangered Devils Hole pupfish, Cyprinodon diabolis, lives in a single warm-pool of unknown depth within Death Valley National Park, California/Nevada.  Over the past few years, C. diabolis has reached record-low numbers, spurring renewed conservation and recovery efforts.  Although factors that influence spawning may be important in regulating C. diabolis population size, much is still unknown about the reproductive ecology of this notoriously difficult-to-breed species.  Over 11 months, February-December 2010, we monitored spawning behavior of C. diabolis and associated environmental conditions within Devils Hole.  A solar-powered video surveillance system, incorporating both above-water and underwater cameras, provided continuous monitoring of the shallow spawning shelf.  Datalogging meters continuously recorded dissolved oxygen, temperature, pH, and sunlight intensity across the shelf.  In-person surveys recorded time-lapse algal and substrate composition, and algal density across the breeding shelf.  Relationships between spawning frequency and associated environmental conditions exemplify the largely seasonal spawning activity of C. diabolis.  Additionally, our experiences highlight some of the successes and limitations of remote-monitoring equipment, and how these instruments might be more broadly applied within the aquatic sciences research arena.  The results from this study will hopefully provide information important for designing C. diabolis captive breeding programs.