Ash Meadows Fish Conservation Facility: Establishing a Devils Hole Pupfish Population

Authors: Feuerbacher, Olin G, Weissenfluh, Darrick S, Chaudoin, Ambre L, Barlics, Robert M, Simons, Lee H, Linares-Casenave, Javier

Year: 2014 (xlvi)

Abstract

Recovery efforts for Devils Hole pupfish, Cyprinodon diabolis, at the Ash Meadows Fish Conservation Facility (AMFCF) have focused on establishing a captive population from eggs collected from Devils Hole. Eggs were recovered from Devils Hole using nylon spawning mops or carpeted tiles during November 2013 and January 2014. Mops and tiles were deployed 1-7 days on the shallow shelf and subsequently transported to AMFCF where they were inverted and agitated underwater to dislodge eggs and detritus. Recovered material was examined with microscopes to detect eggs. We recovered a total of 60 eggs and one larvae from Devils Hole. Only 65% (n=39) of the eggs contained viable developing embryos. Hatching rate was 55% (n=33) and survival to adulthood was 88% (n=29). Rearing methods included treatment of recovered eggs with formalin, malachite green, and trimethoprim sulfamethoxazole, followed by incubation in acrylic hatching cones. Larvae were given probiotics upon first drinking, and fed a mix of infusoria, newly hatched Artemia, Zeigler larval diet, and crushed Rio Grande Silvery Minnow Chow. As fish grew, they were transitioned onto a gape-appropriate combination of frozen and dry feeds. Adult fish (n=29) were moved in May-June 2014 into a 100,000-gallon refuge tank designed to emulate the Devils Hole environment. Fish spawning behaviors have been observed frequently within the refuge tank and successful reproduction has been confirmed via snorkel survey. Three larvae over 10 mm TL and one larvae <10 mm TL were observed on August 15 and September 24, 2014, respectively. Efforts are now focused on improving the reproductive output and survival to adulthood of the captive population.

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