Research and monitoring efforts target recovery variables of the Devils Hole pupfish Cyprinodon diabolis and its ecosystem.

Authors: Kevin P. Wilson, Bailey Gaines, Jeffrey Goldstein, John Wullschleger

Year: 2011 (xliii)

Abstract

The Devils Hole pupfish population began to decline in the mid-1990s and remains well below historic levels. Autumn adult counts from 2009, 2010, and 2011 were 125, 118, and 118, respectively; Spring adult counts for the same period were slightly lower or similar (2009 = 70, 2010 = 120, and 2011 = 104). Historically, counts ranged from 400 and 550 adults in the Autumn and from 200 to 300 in the Spring. Program staff from Death Valley National Park (DEVA), in cooperation with the US Fish and Wildlife Service (USFWS), Nevada Department of Wildlife (NDOW) and several academic institutions have been conducting research into ecological changes that may have contributed to reduced population size of the Devils hole pupfish. Hypotheses are driven by an ecosystem model and a Devils Hole population influence model. A Long Term Ecosystem Monitoring Plan (LTEMP) was implemented in August 2011 by DEVA staff following completion of peer-review and compliance. The LTEMP focuses on abiotic and biotic variables that influence ecosystem processes and composition. Development of a thermodynamics model was initiated in winter 2009by the University of Nevada Reno (UNR). This model is based on data from fiber-optic cables that measure temperatures vertically to a depth of 40 meters and over the shallow shelf. These data will be used to answer questions related to the relationship between water temperature, water level and climate change. A metabolism/nutrient/ecosystem production study started in August 2011 by Ball State University (BSU). This project is using microelectrode technology to measure hydrogen sulfide (H2S), dissolved oxygen (DO), pH, and temperature (°C) in dominant biofilms found in Devils Hole. to investigate the effects of the increased presence of the bacterium Beggiatoa sp. This bacterium has filaments that contain elemental sulfur , which removes dissolved oxygen from the sediment-water interface. Reduction in DO could ultimately reduce egg hatching success of pupfish. A Devils Hole pupfish population-modeling project through Iowa State University is nearing completion. The population model is incorporating data collected from early-life Stage (fish larvae) monitoring, a length-frequency study using stereo-video, and adult counts. Using both applied and basic research should provide managers with data to make informed recovery decisions for the Devils Hole pupfish and its ecosystem.