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Abundance and Habitat-related Use of White Sands Pupfish

Duration

December 2013 - November 2019

Narrative

Capture-Recapture and Occupancy Modeling of White Sands Pupfish - Small-bodied fishes represent a monitoring challenge when they are locally abundant, short-lived, and alter their reproductive strategy as environmental conditions vary. Use of minnow traps with an index of abundance (i.e., catch-per-unit-effort, CPUE) for White Sands pupfish (Cyprinodon tularosa) can be affected by basic methodological choices such as trap soak time (i.e., effort) as well as the timing and location of trap placement. Movement into and out of minnow traps by the pupfish affected CPUE. White Sands pupfish exited traps at frequencies that were nearly equivalent to the rate of entering, suggesting total catch and thereby CPUE, are strongly influenced by factors that determine the probability of an animal exiting the trap. In addition, CPUE was weakly correlated with a more robust estimate of abundance (Lincoln-Peterson estimator) suggesting CPUE is not a good index for abundance especially when trap soak times are variable.

Validation of Otolith Deposition in Laboratory and Field-reared White Sands Pupfish - Otolithic organs (earbones in fish) can be used to accurately evaluate the age of a fish. If otolith increments are deposited daily and time of hatch (onset) is known. To use this aging technique for White Sands pupfish, a validation study was initiated to characterize deposition of daily increments and retrospectively relate the number of otolith increments with the known age of the fish. Sagittal otoliths were pulled and aged for pupfish of known age ranging from day 1 post-hatch to day 90 post-hatch. Validation is underway at the time of this report, but should be completed fall 2016. A similar study is underway outdoors to validate otolith development under natural diel temperature swings and assess fish growth.

Reproductive Strategies of White Sands Pupfish inhabiting Stable versus Unstable Habitats - White Sands pupfish was used to test the hypothesis that mate choice strategies are influenced by environmental stability. Wild fish were collected from two locations each characterized by either highly variable flows marked by stream drying and extreme temperatures or stable flows with consistent diel patterns of water temperature. Detectable differences were observed between pupfish from stable versus unstable stream environments in both the distribution of eggs. Additionally, reproductive effort was detectably different between fish from stable versus unstable environments. These results suggests that reproductive investment may decrease as habitat stability decreases due to the breakdown of reliable reproductive signals.

 

Current Staff

Federal Staff: 102

Masters Students: 247

Phd Students: 163

Post Docs: 55

University Staff: 266

5 Year Summary

Students graduated: 722

Scientific Publications: 1960

Presentations: 4355

 

Personnel

Funding Agencies

  • White Sands Missle Range -Environmental Surveillance Division

Links

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