| Title Fish in the Desert: A study of two divergent populations of pupfish in Death Valley National Park | ||||||||||||||||||||||||||||||||||||||||||||
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Author Melody Martin American River College, Geography 350: Data Acquisition in GIS; Spring 2009 | ||||||||||||||||||||||||||||||||||||||||||||
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Abstract This is an attempt to model the Endangered Devils hole pupfish with the unendangered Salt Creek Pupfish. if this is successful that small groups of salt creek Pupfish can be studied gain a better understanding of the Devils Hole Pupfish without endangering them further. | ||||||||||||||||||||||||||||||||||||||||||||
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Introduction This is a study of the more abundant, non-endangered Salt Creek Pupfish found in Central Death Valley to hopefully be used as a model for the endangered Devils Hole Pupfish found in a satellite area of Death Valley National Park. I will create two maps of the area, one an overview of the entire Death Valley and one zoomed in to just the two relevant areas for this study. | ||||||||||||||||||||||||||||||||||||||||||||
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Background Both species of pupfish are considered to be survivors from the Pleistocene era about 1.8 million years ago. The Salt Creek Pupfish (Cyprinidon salinus Miller) is a remnant species from a Pleistocene Lake currently known as Lake Manly. The Devils Hole Pupfish (Cyprinidon Diabolis) are thought to have existed at their current location for about 60,000 years and have been isolated for about 20,000 years (Anderson and Deacon, 2001 pg 227). The Salt Creek Pupfish are about 1.5 inches long and are mostly a dull coloration with the exception of the generally larger males which have blue and orange patches which are at their brightest in spring. The Devils Hole Pupfish are about one inch long and both are a bright blue color and have no pelvic fin. The Salt Creek pupfish live to about to 2 years, live in water that is twice as saline as the ocean, can withstand temp changes from 130 F to 40 F(and will burrow on the mud bottom to keep warm), need only about 1-2 inches depth of water, and display a remarkable plasticity in being able to readily adapt to freshwater conditions. The Devils Hole Pupfish live one year or less, need a water tempature of ~95 F, need several feet of water depth, and seem to have nowhere near the plasticity of the Salt Creek Pupfish. However, Devils Hole Pupfish can and will interbreed with other kinds of pupfish if given the chance, this was especially noted in some of the early refugia that were established (Lema 2008).(Pictures of both salt Creek Pupfish and Devils Hole Pupfish)
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Methods Most of the sources I found were popular articles and websites on the internet but I did find two relevant articles, one on the "Phenotypic Plasticity of Death Valley's Pupfish" (Lema 2008, American Scientist) and the other "Population size of Devils Hole Pupfish (Cyprinodon diabolis) Correlates with Water Level"(Anderson and Deacon, 2001 Copeia). I also spent quite some time on the phone calling different Fish&Game offices(many thanks to the Las Vegas branch of Fish&Game especially Paul Barrett for providing all the Devils Hole counts) as well as the NPS of Death Valley to get population counts for Devils Hole Pupfish for 2000-2009 as well as any counts or population estimates of the Salt Creek Pupfish. I also downloaded a Death Valley elevation dataset courtesy of USGS that I then proceeded to add to with several heads up digitizing of both the Outline of the Park (since the outline provided was next to useless) and also digitized the approximate locations of Salt Creek and Devils Hole as well as the shapes of them. Overview Map (a more detailed map to follow later). 
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Results | ||||||||||||||||||||||||||||||||||||||||||||
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Table of fish count populations at Devils Hole for the past several years. (Notes- For the 2000-2004 years an average was taken of multiple counts in both fall and spring, after
2004 only one count was taken each spring and fall. For all the averages a result of .5 or higher was rounded up and only those lower than .5 were rounded down). |
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Analysis
It was extremely hard to locate the count data online and much of the data that I could find was either spotty or much too old to be useful. It was also not easy to find a relevant dataset that was free that was in ready to go format, I had to digitize the park outline and re symbolize the elevation data so it stood out better. I finally ended up making many a phone call to different agencies to get the pupfish counts(never heard back from the person at NPS about any counts or population estimates for Salt Creek Pupfish)
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Conclusions
It became obvious very quickly that the Salt Creek Pupfish, while closely related, were too different to use as a model. More research is needed to see what other solutions can be found to save the Devils Hole Pupfish
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References Anderson and Deacon "Population size of Devils Hole Pupfish(Cyprinodon diabolis) Lema "The Phenotypic Plasticity of Death Valleys Pupfish" American Scientist 2008 no 2 USGS Datasets Paul Barrett, Dept. of Fish & Game (pupfish counts) |
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