Award Date

May 2017

Degree Type


Degree Name

Master of Science (MS)


Life Sciences

First Committee Member

Frank van Breukelen

Second Committee Member

Jenifer Utz

Third Committee Member

Jef Jaeger

Fourth Committee Member

Daniel Thompson

Fifth Committee Member

Stanley Hillyard

Number of Pages



Pupfish from the genus Cyprinodon are among the most endangered groups of fishes on the planet, with nearly 40% of species being threatened with extinction. These pupfishes are often assumed to be the most temperature tolerant of all fish, coping with temperatures as low as 0 °C and as high as 44 °C. However, conflicting data exist and certain measures of thermal tolerance are not markedly higher in pupfish compared to common game fish. Pupfish egg production and growth has been known to be hampered at temperatures well below what they apparently experience in nature. I addressed why eggs fail to hatch at high temperatures using reciprocal transplant experiments and measurements of oxygen consumption over the course of development. Parental thermal history appears to influence successful hatching more than egg incubation temperature. Eggs which are reared at the ecologically relevant temperature of 33 °C exhibit altered and unusual oxygen consumption patterns compared to eggs incubated at a lower temperature. I employed a capture-mark-recapture study and field experiments in a dynamic and hypervariable creek environment (Salt Creek, CA) to determine whether individual pupfish which experience temperatures as high as 40 °C survive long-term. Pupfish in Salt Creek appear to colonize warm environments during the spring when conditions can be favorable for growth and reproduction; however, these fish risk death by desiccation and heat exposure if they remain in warm environments during the summer months.


ash meadows; cyprinodon; devils hole; pupfish; salt creek; thermal ecology


Environmental Sciences | Medical Physiology | Physiology | Terrestrial and Aquatic Ecology

File Format


Degree Grantor

University of Nevada, Las Vegas




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