Effects of salinity on White Sands pupfish (Cyprinodon tularosa) reproduction and population size

Authors: David L. Rogowski, Craig A. Stockwell

Year: 2008 (xl)

Abstract

Pupfish (Cyprinodonts) are generally able to tolerate a wide variety of salinities and are one of the few fishes to have successfully exploited this niche. With habitat loss being the greatest threat to their existence, it is increasingly important to create refuges and artificial propagation techniques. While pupfish are euryhaline, optimum salinities for growth and reproduction may actual differ from salinities levels currently present in habitats where pupfish occur. Previous research has shown that the White Sands pupfish (Cyprinodon tularosa) should be managed as two separate evolutionary significant units (ESU), Salt Creek and Malpais Spring populations. We investigated pupfish reproduction and population size at low (3.3) and high salinity (25) representing salinity regimes in Malpais Spring and Salt Creek respectively. Replicate populations were monitored over the period of a reproductive season (128 days) in outdoor mesocosms. Both strains did better in the low salinity environment. However, only the Salt Creek strain in the low salinity treatment had significantly higher recruitment and population size. There was not a significant difference in recruitment, and population size among the other treatments (both high salinity treatments, and low salinity Mound Spring treatment).