Devils Hole Pupfish
Recovery Actions, April 21, 2006
Surveys conducted in April 2006, located 11 larvae and 38 adult Devils Hole pupfish in their natural environment. Spring pupfish populations are typically lower than fall population numbers. Since the population in November 2005 was only 84 individuals, it was anticipated that the spring survey might also be low.
While this is a record low count and the long term trend is still downward, there appeared to be a high number of young fish, indicating that there has been successful spawning.
A population at the Hoover Dam Refuge was also surveyed and yielded a total number of 29 individuals. Approximately half of those fish were estimated to be young fish, also indicating that successful spawning is occurring.
Management decisions have been elevated to the Regional Directorate level of the Service and National Park Service, and Director of the Nevada Department of Wildlife. The Directors are consulting with members of the Recovery Team, additional propagation experts, and agency biologists and managers. All three agencies have committed full time staff to work on implementing subcommittee recommendations.
The Managers have restricted activity in Devils Hole. Any entry into Devils Hole must be approved by the Regional Managers. A new monitoring platform will be installed to reduce impacts to the hole as well as the expansion of the perimeter fence.
In order to understand how to successfully propagate this pupfish in aquaria, techniques recommended by experts from across the United States and Mexico are being tested using a hybridized Devils Hole pupfish from the Point of Rocks Refuge. Willow Beach National Fish Hatchery (NFH) and Shark Reef Aquarium at Mandalay Bay Resort will be immediately utilized for these propagation efforts.
Dexter National Fish Hatchery and Technology Center is providing genetic expertise to be utilized in conjunction with the propagation efforts. Bozeman Fish Technology Center (FTC), in coordination with New Mexico State University, has developed an experimental diet specifically for Devils Hole pupfish to be utilized in these propagation efforts.
Five action plans are being developed to guide short and long term decisions in genetics management, propagation, monitoring of fish and water quality, and public outreach. A decision support document is being created that will incorporate elements of the five plans to assist in management decisions. The decision support document will determine points in time (triggers) when fish from Hoover Dam Refuge and Devils Hole will be used to maintain or increase genetic viability of captive reared stock.
Efforts to increase the population of Devils Hole pupfish will continue at the Hoover Dam Refuge.