Environmental Factors in Spawning of Wild Devils Hole Pupfish Cyprinodon diabolis (Teleostei: Cyprinodontidae)
The sole wild population of the endangered Devils Hole Pupfish, Cyprinodon diabolis, has declined to fewer than 40 individuals twice since 2006, prompting increased recovery efforts. The U.S. Fish and Wildlife Service's Devils Hole Pupfish recovery plan stipulates two reproducing captive populations, though, historically, propagation efforts have yielded little success. To address information deficits in reproductive behavior and ecology, from February–December 2010 we investigated environmental factors associated with spawning activity of C. diabolis in Devils Hole, Nevada, USA. An underwater camera continuously monitored a portion of a shallow, submerged rock shelf used for spawning. Select biotic, abiotic, and physico-chemical parameters were monitored continuously throughout the year. Water level and precipitation data provided by the U.S. National Park Service identified disturbances from earthquake-induced seiches and storm-induced flash floods. Zero-inflated Poisson regression provided a model with 28% predictive power with algal cover, light energy, and seiches as the three strongest predictors among tested factors in spawning behavior of C. diabolis in the wild.
The shallow shelf in Devils Hole, Nevada before (left) and after (right) an earthquake on 8 September 2017 (UTC) centered 87 km SW of Pijijiapan, Chiapas, Mexico that registered a magnitude of 8.2 on the Richter scale. The resulting seiche produced waves up to 6 ft (1.8 m) high, cleared the shelf of biological materials, and redistributed and removed substrate, increasing average water depth on the shelf by 0.2 ft (0.06 m [unpubl.]). Photo credit: U.S. National Park Service.
(A) Devils Hole Pupfish spawning frequency as recorded by a fixed underwater video camera on the shallow shelf in Devils Hole, Nevada in 2010 (n = 522 5-minute samples). (B, C) Daily maximum, minimum, and mean values for (B) water temperature and (C) dissolved oxygen (DO) in the water column above the shallow shelf. A Thermo Orion 3Star Portable RDO datalogging meter recorded temperature (±0.3°C) and DO every 30 min. A temperature/optical DO probe was deployed above the substrate in approximately 26.5 cm deep water. Gaps represent missing data due to instrumentation failure. (D) Daily maximum light intensity (103) and total daily light intensity (104) at the water surface over the shallow shelf. A SPER 850008 Datalogging Light Meter recorded light measurements every 15 min three to six days per month from approximately one meter above the water surface. (E) Algal/cyanobacteria cover on the shallow shelf benthos. Cover was surveyed one or two times monthly using a modified Braun-Blanquet/Daubenmire method (Braun-Blanquet, 1932; Daubenmire, 1959).
Spawning frequency of Devils Hole Pupfish 72 hours before and after three earthquakes that created large seiches and redistributed materials on the shallow shelf in Devils Hole: 1) 26 February 2010, 2234 hours PST/27 February 2010, 0634 hours UTC, 8.8M, centered off the coast of central Chile; 2) 4 April 2010, 1540 hours PST/2240 hours UTC, 7.2M, centered just south of Guadalupe Victoria, Baja California Peninsula, Mexico; and 3) 21 October 2010, 1053 hours PST/1753 hours UTC, 6.7M, centered in the Gulf of California. Error bars are ±SE.
Contributor Notes
Associate Editor: W. L. Smith.