Devil's Hole pupfish
The Devils Hole pupfish (Cyprinodon diabolis) was listed as endangered in 1967. This iridescent blue inch-long fish's only natural habitat is in the 93 degree waters of Devils Hole, located within the Ash Meadows National Wildlife Refuge, Nye County, Nevada, which is a detached unit of Death Valley National Park . Although the cavern is over 400 feet deep, the pupfish are believed to spawn exclusively on a shallow rock shelf just under the waters surface.
Photo: Devils HoleSince population surveys began, Devils Hole pupfish numbers have not exceed 553 individuals. For reasons that are still unclear, the population of Devils Hole pupfish began to decline in the mid 1990’s. By the fall of 2006, an estimated 38 fish remained in the wild and two refuge populations were lost.
Past research demonstrated that their population naturally cycles in Devils Hole with the largest number of pupfish occurring in the fall and declining over the winter. Although they spawn year round in the constant 93°F water, the adults that survive the winter produce most of the next generation of pupfish in the spring.