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Compare and Contrast the Water

environment between Death Valley Pupfish

Specie and Devil’s Hole Pupfish Specie

By Roy Tianran Gao

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Table of Contents

Title page 1

Abstract 3

Introduction and Background 3

Water Temperature 4

Salinity 6

Water Level 7

Conservation 10

Conclusion 11

References 12

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ABSTRACT

The two types of pupfish (Cyprinodon) in Death Valley National Park are Death Valley

pupfish and Devil’s Hole pupfish. Death Valley pupfish has been existed over 10,000 years and

Devil’s Hole pupfish has been existed for over 20,000 years. Both of the pupfishes are

endangered species. The average number of Death Valley pupfish has decreased by about 100

since 1990s, and the number of Devil’s Hole pupfish has decreased by 400 since 1995.

Comparing the water level, water temperature and the water salinity between the two species of

pupfish would help to define the living requirements and reason of decreasing population. The

research toward the result is based on 7 journal articles, 4 websites, and 1 book. As the result

shows, Death Valley Pupfish and Devil’s Hole Pupfish live in different water environments and

functioned differently. Understanding the water environment of the two types of pupfishes will

help people building new habitats for pupfishes and increase their population so that would be

possible to avoid the extinction of pupfishes from the earth.

INTRODUCTION AND BACKGROUND

Pupfish is a small killifish in the Southwest of America. There are five pupfish species in

Death Valley which are Armargosa pupfish, Saratoga Pupfish, Devil’s Hole pupfish, Death

Valley pupfish, and Cotton ball Marsh pupfish (National Park Service, 2008). Different types of

pupfish live in different environments and have different size and functioned differently. Death

Valley pupfish and Devil’s Hole pupfish are currently the two endangered species in Southwest.

As Map 1 shows, Death Valley pupfish is located in Salt Creek where in the center of Death

Valley between the Panamint Range and Armargosa Range so the Death Valley pupfish also

called Salt Creek pupfish, and Devil’s Hole is located in Ash Meadows, Death Valley which is

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approximately 60 kilometers from Salt Creek (National Park Service, 2008). Although the two

species are not too far from each other, their climates represent differently and directly affect the

living conditions of pupfish in these two species. Salt Creek Species is hot and dry, the average

annual temperature is about 32 degree Celsius, and the annual precipitation is about 5 cm. Also,

the elevation of Salt Creek Species is about 64 meters below the sea level (National Park

Service, 2008). The Devil’s Hole Species’ annual temperature is approximately 18.5 Celsius

with annual precipitation in average between 7.5 cm and 10cm (Dudley and Larson, 1976).

Physically looking, the Death Valley pupfish is about 6-9 cm long (Figure 1), which is bigger

than the Devil’s Hole pupfish, the Devil’s Hole pupfish is only about 2-3 cm long (Figure 4).

They eat algae and other invertebrates. Most of the pupfishes live between 6 to 9 months and

some of them could live over one year. Since the two species affected by different climates, the

water condition in both locations are also different. In this paper, water condition will be

discussed in three aspects that could affect pupfish: the water temperature, the water level, and

the water salinity.

WATER TEMPERATURE

Because Salt Creek is hotter than Devil’s Hole, Death Valley pupfish has a better heat

tolerance than Devil’s Hole pupfish. The temperature fluctuation in Salt Creek is quite large, the

air temperature seasonally from below 0 C to greater than 50 C. There are some days with

extreme hot or cold temperature in the water which would affect more on the pupfish (Brown

and Feldmuth, 1971). Robert G. Otto and Shelby D. Gerking, who are from Arizona State

University studied Death Valley pupfish with a water temperature test. There are two

measurement were used in their test, the Critical Thermal Maximum (CTM) and upper lethal

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temperature. The CTM is measuring the ability that pupfish would withstand in a high

temperature, and the upper lethal temperature is telling long-term heat stress for the pupfish ---

Map 1, Locations of Salt Creek and Devil’s Hole, where the species of Death Valley pupfish

and Devil’s Hole pupfish at.

Figure 1, Death Valley Pupfish, 6-9 cm long in Salt Creek, Death Valley.

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--- (Otto and Gerking, 1973). There result shows that the Death Valley pupfish would be able to

with stand in a water temperature as high of 45.3 Celsius, and the water temperature between 35

and 40 degree Celsius is the when Death Valley pupfish active the most ( Otto and Gerking,

1973). Pupfish not be able survive in low temperature water. When the water temperatures reach

6 degree Celsius, the Death Valley pupfish tend not to activate in the water. For Devil’s Hole

pupfish, there is no one has done any temperature test towards Devil’s Hole pupfish. However,

Matthew Anderson and James Deacon introduced the general trend for Devil’s Hole pupfish.

During the summer, the water temperature in Devil’s Hole usually between 30 and 33 Celsius,

and the population of pupfish tend to increase and more activate. During the winter time, the

water temperatures often reach below 5 degree Celsius, and Devil’s Hole pupfish tend to stay

deeper in the water and the population tend to decrease.

SALINITY

Salinity is another factor that would impact pupfish. As Salt Creek is located in an

enclosed basin, and there are approximately 15,000 square kilometers of salts in this basin that

usually from a large drainage system, it caused the groundwater mixed with salts in this basin

(National Park Service, 2008). In Salt Creek specie, the salinity of water in average is about 10-

12% (USGS, 2011). In the summer the salinity increase very high and crystallizes into salt when

the water evaporate, and during the winter, salinity goes down to 5% (USGS, 2011). Because the

salinity in Salt Creek is very high, the Death Valley Pupfish use their gills to take out the salt and

keep the water inside of their bodies.

In Devil’s Hole, salts do not influence the ground water system. The aquifer system in

Devil’s Hole works differently. “The aquifers are composed predominantly of limestone and

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dolomite which transport water freely through fractures that have been enlarged by dissolution of

the carbonate minerals. The aquitards contain only minor thicknesses of soluble rocks and are

composed chiefly of clastic rocks that impede the flow of ground water. Because of their

geometric distribution, the aquitards function most importantly to restrict lateral ground-water

flow, thus determining the boundaries of the Ash Meadows ground-water system” (Dudley and

Larson, 1976). One other part that Devil’s Hole specie different from Death Valley specie is

that Devil’s Hole pupfish could not use their gills to keep the salt out of their body, and the

water in Devil’s Hole is all fresh water. One of the main reason that water in Devil’s Hole keeps

fresh because Devil’s Hole is 609 meters above the sea level which allow its water to avoid salt

effect from the salt pan.

WATER LEVEL

Salt Creek specie is a loop about 1000 meter long and only 8-10 cm deep in average

(National Park Service, 2008). Water level in Salt Creek does not change significantly which

means that the Death Valley pupfish does not influence by the local water level.

However, Devils Hole as one of the oldest and the most famous pupfish habitats located

in Ash Meadows, Death Valley contains the thermal water (33 C) which is the ideal water for

pupfish (Anderson and Deacon, 2001). Devil’s Hole itself is a water-filled cavern cut into the

side of a hill. The cavern is over 150 meters deep and the bottom has never been mapped

(National Park Service, 2008). As Matthew Anderson and James Deacon argued that the change

of water level would influence the population of Devil’s Hole pupfish. Adult pupfishes in Devils

Hole usually occupy the upper level of the water which is about 26m and with a high density in

the upper 15m deep of water because the sunlight could penetrate into the water. This is

important because when the sunlight penetrates into the water, the water temperate increase and

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it is easier for pupfish to live. The north side of the Devils Hole pool is about 130m deep and the

southern side with the shallower water is about 5m deep (Szabo, Kolesar, Riggs, Winograd and

Ludwig, 1994). During the winter time, when the temperature gets low, the pupfishes tend to be

in the deeper water to stay warm. However, the water level during the winter tends to be lower

than in the summer, and that significantly affect the population of pupfishes in Devils Hole.

Figure 2, Annual minimum and maximum estimated populationsize for Devils Hole

pupfish from 1972 to 1997

Figure 2 shows that during the period between 1972 and 1976, the change of annual

variation in population size was the lowest. During the period between 1976 and 1988, the

change of annual variation in population size was the highest and the total population of pupfish

also increased significantly (Anderson and Deacon, 2001). The change of pupfish population

corresponded the water level in Devil’s Hole, when the change of population stays small

between 1972 and 1976, the water level remained low, when the population size increased

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rapidly after 1976, the water level rises. This is because when the water level gets higher; there

will be a better chance for pupfishes to get food and helps spawning so that more larval would be

able to survive to increase the maximum population size. The water level in Devils Hole is

determined by regional climatic conditions in the Southwest, which have varied over 20,000

years (Anderson and Deacon, 2001).

Figure 3, Devils Hole in Ash Meadow National Refuge where is Devil’s Pupfish’s only

habitat.

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Figure 4, Devil’s Hole pupfish, which is blue color that different with Death Valley

pupfish, only about 2-3 cm long.

CONSEERVATION

Both Death Valley pupfish and Devil’s Hole pupfish are endangered species and needed

to be protected. The Death Valley pupfish is facing the problem of lacking of water in Salt Creek

especially in the summer when lots of water evaporated and the creek began to dry out. On one

hand, the National Park Service since 2008 have already start to look for new habitats for Death

Valley pupfish and see whether they can fit into the new environment. On the other hand,

workers in Death Valley National Park are considering moving some water to Salt Creek when

necessary in the summer (National Park Service, 2008). Neither way were not fully approved

that could cause the increasing of pupfish population so that these methods are still needed to be

discussed.

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Devils Hole as located in Ash Meadows now become the Ash Meadows National

Wildlife Refuge. As the water cross the Mojave Desert is less abundant today than it was 11, 000

years ago, the number of pupfishes has decreased from average 600 to 300 during the past few

years and therefore the pupfish in Ash Meadows national Wildlife Refuge was one of the first

fishes to be listed as endangered, and the pupfish is the only specie in Devils Hole and have lived

in there for about 20,000 years (Szabo, Kolesar, Riggs, Winograd and Ludwig, 1994). Increasing

the total population of pupfishes would be the best way to protect them. The reproduction for

pupfish is approximately from January to July and reaches a peak in April and May (Minckley

and Deacon, 1973). During the summer, concentration in the shallower water tends to maintain

high because of the warm temperature and as the water level increases during the summer, it

would be easier for pupfishes to find food and have more offspring. However, one serious

situation towards Devil’s Hole pupfishes is how to protect them. The Devil’s Hole recovery plan

of 1980 the U.S. Fish and Wildlife Service designated as essential habitat about 21,000 acres

where the groundwater most influenced the water level in the Hole. One of the identified goals of

the recovery plan was to maintain the aquifer at such levels that the population fluctuates from

300 in winter to 700 – 900 in late summer (National Park Service, 2008). Even though there are

many habitats in Death Valley were built, the Devils Hole as one of the best and oldest location

for pupfishes, the algae in Devils Hole could not grow regularly and hundreds of pupfishes live

in Devils Hole would have trouble to find food because algae is basically what they eat.

CONCLUSION

In final consideration, this paper compared the water environment of the two species

between Death Valley and Devil’s Hole. The water temperature, water salinity and water level

were involved and discussed. As the result shows, Death Valley pupfish and Devil’s Hole

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pupfish functions very differently due to their different environment. Devil’s Hole pupfish

seems to have more issues that needed to be deal with due to its high requirements towards the

water environment. Since this paper discussed with the water temperature, salinity and water

level requirements for both pupfishes, we shall have a better knowledge about the two species

and help to protect these endangered species. The decreasing of pupfish has become a mystery

and no one could tell the reason, but this is the problem that we shall all concern about. Both Salt

Creek and Devil’s Hole are the only species for both types of pupfish, if the population keeps

decreasing, both types of pupfishes will extinct. More research need to be done towards pupfish

and also more people shall know this serious issue and start to protect the environment because a

very little thing we do to help the environment would make a change on pupfish species.

REFERENCE:

Andersen, E.Matthew and Deacon, E. James,2001, Population Size of Devils Hole Pupfish

( Cyprinodon diabolis) correlates with Water Level Copeia, Vol. No. 1, pp. 224-228

Brown, J.H, and C.R. Feldmuth. 1971. Evolution in constant and fluctuating environments:

Thermal tolerances of desert pupfish (Cyprinodon). Evolution 25: 390 – 398)

Devil’s Hole pupfish, 2009, http://joannamarple.com/?attachment_id=4227

Dudley, W.W. JR, and Larson, J.D, 1976, Effect of Irrigation Pumping on Desert Pupfish

Habitats in Ash Meadows, Nye County, Nevada, V. 3, P. 5-43.

Hegel. Lewis Center, 2012 Pupfish, Photograph, from Britannica Online for Kids, accessed

December 22, 2012, http://kids.britannica.com/comptons/art-166922.

Hunt, Charles.,1976, Death Valley, Geology ecology archaeology, 1st ed. Los Angeles: The

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Regent of the University of California

Minckley, C. O., and J. E. Deacon, 1973. Observations on the reproductive cycle of

Cyprinodon diabolis. Copeia: 610-613

National Park Service, 2008, Death Valley Project,

http://www.nps.gov/deva/naturescience/weather-and-climate.htm

Otto, G. Robert, and Gerking D.Shelby, 1973. Heat Tolerance of a Death Valley Pupfish (Genus

Cyprinodon) Physiological Zoology, Vol. 46, No. 1, pp. 43-49

Szabo, B. J., Kolesar, P. T., Riggs, A.C., Winograd, I. J., and Ludwig, K. R.. 1994. Paleoclimatic

Inferences from a 120,000-yr calcite record of water table fluctuation in Browns

Room of Devils Hole, Nevada. Quat. Res. 41:59-69

United States Geological Survey, 2011, http://www.usgs.gov/