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STATUS OF THE DESERT PUPFISH,
CYPRINODON MACULARIUS (BAIRD AND GIRARD),
IN CALIFORNIA

Glenn F. Black

RESULTS

Irrigation Drains

A total of 13 species of fish an&l invertebrate species was captured during the surveys of the irrigation drains (Appendix 1). The most abundant species was the sailf in molly, which accounted for 73%, 90%, 86%, and 73% of the catch in the spring, summer, fall, and winter surveys, respectively (Figure 3). This species comprised 85% of the total catch from the four surveys combined (Figure 3). The sailf in molly was most numerous in the su~er survey, when almost 4,000 were cantured; this was 2.5 times more than in the fall survey and 5 times more than in the spring and winter surveys (Figure 3). This species also had the widest distribution since it occurred in at least 14 drains on each survey and overall was sampled from 17 of the 18 drains surveyed (Appendix 1).

African cichlids were the next most abundant fish sampled (Figure 3). Taxonomic identification of Zill's cichlid and the Mozambique mouthbrooder can only be determined by counting gill rakers. Since the minnow traps were selective for only the juveniles (fish less than 7.6 cm TL), both species were tabulated together in this report. The adults of the two species can be easily distinguished based on coloration.

 

FIGURE 3.Seasonal distribution of species captured in 18 irrigation drains during desert pupfish surveys at the Salton Sea. Numbers above the bars refer to total number captured. A sailfin mollies, B = red shiners, C = crayfish, D = African cichlids, E = desert pupfish, F = other species, C = shortfin mollies.

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It was noted that all adult African cichlids observed in the irrigation drains were Zill's cichlids. Thus) it is probable that the majority, if not all the cichlids captured were Zill's cichlids. African cichlids contributed to 2% of the catch in the spring survey, 3% in the summer survey, 7% in the fall survey, 13% in the winter survey, and 5% of the combined catch from the four surveys (Figure 3). The number sampled was relatively constant during the summer (119), fall (134), and winter surveys (144), however, theywere extremely low in the spring survey (17) (Figure 3). These fish were also the second most widely distributed species sampled throughout the irrigation drains occurring in as many as 12 drains during the fall survey to as few as five drains during the spring survey and overall were sampled from 16 drains (Appendix 1).

The crayfish, Procambarus clarkii, made up 2% of the catch in the spring and summer surveys, 3% in the fall survey, 1% in the winter survey, and 3% of the combined catch from the irrigation drains (Figure 3). Crayfish were most numerous in the summer survey when 99 were captured and least numerous in the winter survey when only 16 were found (Figure 3). Their distribution was limited to as few as three irrigation drains during the fall survey and to as many as seven during the spring and summer surveys; crayfish were found in 10 different irrigation drains during the four surveys (Appendix 1).

The desert pupfish accounted for only 1% of the catch in the spring survey, 2% in the summer and fall surveys, 7% in the winter survey, and 3% of the catch from all four surveys (Figure 3). They were most numerous in the summer survey when 91 were sampled and leastnumerous in the spring when only nine were taken (Figure 3). Their distribution was restricted to as few as three irrigation drains in the winter survey and to as many as eight in the summer survey but overall they were found in 15 of the 13 irrigation drains sampled (Appendix 1).

The ratios of potential predator and competitor species to desert pupfish within the irrigation drains indicated that the relative abundance of pupfish varied tremendously from one drain to the next on any of the surveys and that some variability existed within different habitats of an individual drain (Table 1). With the exception of Vail 3-A and Niland 5 drains, desert pupfish were outnumbered by potential predator and competitor species at every site where pupfish were captured (Table 1).

There were a wide variety of habitat types represented in the drains sampled, and much variation existed between and even within each drain. Sailf in mollies and African cichlids showed no preference for specific habitats, but seemed to be distributed throughout the habitats in an': particular drain. On the other hand, desert ouvfish seemed to prefer drain areas having a sand-silt substrate with either rooted or unattached aquatic plants, and a very restricted surface flow. Dissolved oxygen monitored at sites where desert pupfish were trapped varied from a low of 1.2 ppm to a high of 7.2 ppm (Appendix 2). Pupfish did not appear to select any particular dissolved oxygen level. Turbidity measurements taken at 28 locations where desert pupfish were sampled showed that they preferred water clearer than 75 JTU's (Appendix 2). They were found in salinities ranging from 2,300 to 27,000 ppm with no apparent preference (Appendix 2). With the exception of Vail 3-A drain, 89% of the pupfish were captured in water less than 30 cm, however, in this drain 90% of the pupfish trapped were in water greater than 30 cm (Appendix 2).

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TABLE 1. The Ratios of Potential Predator and Competitor Species to Desert Pupfish as Sampled in Individual Traps Within 15 Irrigation Drains During Quarterly Surveys in the Salton Sea.1/

Drain
Spring
Summer
Fall
Winter

Arthur

204:1
66:1
19:1

Ave. 73

56:1

Ave. 76

20:1
14:1

Barth

14:1
3:1

Grant

19:1

Hayes

40:1

Niland1

2:1

Niland 5

12:1
1:1

Trifolium 7-A

12:1

"U"

17:1

Unnamed

23:1

Vail 3-A

1:8
1:1
1:28

Vail 4-A

34:1

Wheeler

325:1
9:1

265:1
70:1

104:1

"Z"

11:1

17:1

1/Ratios are given only where both pupfish and potential predator/competitor species were found within the same trap.

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The depth of capture may not have much significance since Barlow (1958a) has shown that there is considerable daily movement of desert pupfish in the water column due to temperature preferences, at least in the shore-line pools. There is reason to suspect that daily pupfish movements, in relation to water temperature, also occur in the various depths present in many of the irrigation drains. Courtois and Hino (1979) have demonstrated that desert pupfish prefer water 18-cm to 22-cm deep for egg deposition, so that at least during the breeding season the depth of water available to them is important.

Ten other species were captured in the irrigation drains, but they represented only 4% of the total catch from the four surveys. These species were bluegill, Lepomis macrochirus; yellow bullhead, Ictalurus natalis; carp, Cyprinus carpio; Gulf croaker, Bairdiella icistia; mosquitofish, Gambusia affinis; longjaw mudsucker, Gillichthys rnirabilis; shortfin molly, Poecilia mexicana; porthole fish, Poeciliopsis gracilis; red shiner, Notropis Lutrensis; and threadfin shad, Dorosoma petenense (Table 1, Appendix 1). Carp. Gulf croaker, yellow bullhead, bluegill, and porthole fish were found in only one drain, while longjaw mudsuckers were collected from a total of 12 drains (Appendix 1). Threadfin shad, shortfin mollies, mosquitofish, and red shiners were sampled from a total of two, three, four, and six drains, respectively (Appendix 1). Traps were selective against mosquitofish because they were observed in greater numbers and in more areas than the collection data indicate. Mosquitofish feed primarily at or near water surface, but the traps were rarely set so shallow that trap openings were at or just below the surface.

Shoreline Pools

Five species of fish were sampled from two shoreline pools during the quarterly surveys (Appendix 3). The sailf in molly was the most abundant species sampled during the spring, summer, and fall surveys when it made up 85%, 89%, and 90% of the catch, respectively; during the winter survey it accounted for only 1% of the fish sampled (Figure 4). The combined catches of all four surveys showed that the sailf in molly was the most abundant species contributing to 81% of the total catch from the shoreline pools (Figure 4). Unlike the findings in the irrigation drains where sailf in mollies were most numerous during the summer survey, it was found that they were most numerous in the shoreline pools during the fall survey (Figure 4). The 857 sailf in mollies captured in the fall survey were twice as many as in the spring survey and three times more than in the spring survey. (Figure 4).

The longiaw mudsucker was the next most abundant species in the shoreline pools making up 13% of the combined catches of the four surveys (Figure 4) By contrast, African cichlids were the second most abundant fish sampled from the irrigation drains. The longjaw mudsucker accounted for 3% of the catch in the spring survey, 5% in the summer, 8% in the fall, and 78% in the winter (Figure 4). It was most numerous in the winter survey, when 134 were sampled and least numerous in the spring survey, when only 10 were found (Figure 4). This species was sampled from only one of the two shoreline poo1s throughout the quarterly surveys (Appendix 3).

 

FIGURE 4. Seasonal distribution of species captured in two shoreline pools during desert pupfish surveys at the Salton Sea. Numbers above the bars refer to total number captured. A = sailfin mollies, B = desert pupfish, C = longjaw mudsucker, D = African cichlids,

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Desert pupfish contributed to 11% of the catch in the spring, 2% in the summer survey, 1% in the fall survey, 20% in the winter survey, and 5% of the total catch for all four surveys (Figure 4). Pupfish were most numerous in the spring survey, when 39 were sampled and least numerous in the fall survey, when only nine were sampled (Figure 4). The pupfish was found in both shoreline pools during the spring, summer, and fall surveys, 'but found in only one of them during the winter survey (Appendix 3).

The ratios of potential predator and competitor species to desert pupfish at separate trap sites in each of the shoreline pools shows some variability from one site to another within the same shoreline pools and a great amount of variability in abundancebetween the two pools during the same surveys (Table 2). Based upon this ratio data, it is also apparent that pupfish were consistently more abundant in the Salton Sea National Wildlife Refuge pool than Salt Creek pool (Table 2).

African cichlids and shortfin mollies represented the remaining 1% of the total catch from the four surveys of the shoreline poo1s (Figure 4), A total of 24 cichlids were captured during the spring) summer, and fall surveys, while the one shortfin molly was sampled during the winter survey (Figure 4).

Natural Tributaries

Nine fish species and one invertebrate species were captured during the quarterly surveys of Salt Creek, Whitefield Creek, and the Whitewater River (Appendix 4). As in the surveys of the irrigation drains and the shoreline pools, the sailf in molly was the most abundant species captured, comprising 85% of the species sampled in the spring, 69% in the summer, 68% in the fall, 61% in the winter, and 70% of the total catch from all the surveys (Figure 5). Sailfin mollies were most numerous in the traps during the summer survey, when 866 were collected and least numerous during the winter survey, when only 84 were taken (Figure 5). This was similar to seasonal fluctuations in abundance within the irrigation drains. Sailfin mollies were captured in each of the tributaries during every survey with the exception of the winter survey of Salt Creek (Appendix 4).

Similar to the irrigation drains, African cichlids were the next most abundant species sampled from the natural tributaries, making up 2% of the catch in the spring, 11% in the summer, 14% in the fall, 4% in the winter, and 10% from all the surveys combined (Figure 5). They were most numerous in the summer survey, when 137 were captured and least numerous in the spring survey, when only four were captured (Figure 5). African cichlids were sampled from all three tributaries during three of the surveys conducted (Appendix 4).

The red shiner represented 9% of the total catch from all four surveys of the tributaries (Figure 5). However, 175 of the 178 red shiners collected during the summer survey were from the Whitewater River (Figure 5, Appendix 4).

The longjaw mudsucker accounted for 11% of the catch during the spring, 4% during the summer, 14% during the fall, 13% during the winter, and 6% of the total catch (Figure 5). Mudsuckers were most numerous in the tributaries during the summer survey when 49 were caught and least numerous during the winter survey when only 18 were captured (Figure 5). They were taken from all three tributaries surveyed (Appendix 4).

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TABLE 2. The Ratios of Potential Predator and Competitor Species to Desert Pupfish as Sampled in Individual Traps Within Two Shoreline Pools During Quarterly Surveys at the Salton Sea.

Ratio of predators/competitors to desert pupfish

Shoreline poo1

Spring
Summer
Fall
Winter

Salt Creek

14:1
58:1
188:1
47:1

Salton Sea National
Wildlife Refuge

2:1
1:2
7:1
7:1
15:1
55:1
1:14

 

FIGURE 5.Seasonal distribution of species captured in three tributaries to the Salton Sea during desert pupfish surveys. Numbers above the bars refer to total number captured. A = sailfin mollies, B = longjaw mudsuckers, C = African cichlids, D = crayfish, E = red shiners, F = shortfin mollies, G = other species.

 

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Shortfin mollies contributed to 4% of the total catch from the quarterly surveys of the tributaries (Figure 5). They were found in the tributaries during the summer, fall, and winter surveys and comprised 20% of the catch during the winter survey (Figure 5, Appendix 4).

Five other species, including the desert pupfish, Gulf croaker, carp, mosquito-fish, and crayfish were sampled from the tributaries during the quarterly surveys, but together they made up only 1% of the catch (Figure 5, Appendix 4). Only five desert pupfish were taken from the tributaries: three from Salt Creek during the summer survey and two from Whitefield Creek during the fall (Appendix 4).

Salton Sea Proper

Six species of fish were collected from 13 areas in the Salton Sea (Appendix 5). As in the surveys of the irrigation drains, shoreline poo1s, and the tributaries, the sailf in molly was the most abundant species captured in the Salton Sea proper, making up 98% of the combined catch from all four surveys (Figure 6). This species represented 100% of the catch from the spring survey, 98% from the summer, 99% from the fall, but only 28% from the winter survey (Figure 6). Sailf in mollies were most numerous in the summer survey when 1,356 were captured and least numerous in the winter survey when only five were taken (Figure 6). Their distribution was limited to three sampling areas of the Salton Sea in the spring and winter surveys, but they were found in all 13 sampling locations during the fall survey (Appendix 5). 

Juvenile orangemouth corvina, Cynoscion xanthulus, were the next most abundant species captured in the four surveys of the Salton Sea proper (Figure 6). They made up 1% of the total catch and were taken only during the spring and summer surveys in which they accounted for 1% and less than 1% of the catch, respectively (Figure 6). They were sampled from the mouths of three irrigation drains and off one sandbar (Appendix 5).

African cichlids, Gulf croakers, desert pupfish, and longjaw mudsuckers made up the remaining 1% of the total fish captured in the surveys of the Salton Sea proper (Figure 6). However, the only desert pup.fish captured was off the mouth of Haves Street drain during the winter survey (Appendix 5).

Summary of the Results of the Quarterly Surveys

The surveys of the irrigation drains, shoreline pools, natural tributaries, and the Salton Sea proper clearly show that the sailfin molly was the most abundant and widely distributed of all the species sampled. Only during the winter survey of the shoreline pools and the Salton Sea proper was the sailf in molly not the most abundant species captured; in both cases the longjaw mudsucker was the most abundant species (Figures 4 and 6). The probable reason for the mudsucker being more numerous than the sailf in molly in these two habitats was because of the occurrence of a large die-off of mollies several weeks before the winter surve" (pers. observ.). Although I did not record water temperatures from the Salton Sea during this survey, this may have been due, in part, to colder than normal water in these areas, whereas water in the irrigation drains stays warmer during the winter due to the subsurface flow of irrigation return water (Appendix 2). Sailf in mollies contributed to 78% of the total catch from all habitats sampled during the spring survey, 89% for the summer survey, 88% for the fall survey,and 63% for the winter survey (Figure 7). Overall, the sailf in molly accounted for 85% of the 16,048 fish and invertebrates collected during the quarterly surveys of the four 'habitat types (Table 3). Substantial variability occurred in the numbers of sailf ins captured seasonally from the four habitats sampled (Figures 3 to 7). Relative abundance showed less seasonal variability (Figures 3 to 7).

 

 

FIGURE 6. Seasonal distribution of species captured in 13 areas of the Salton Sea proper during desert pupfish surveys. Number above the bars refer to total number captured. A = sailfin mollies, B = orangemouth corvina, C = African cichlids, D = longjaw mudsuckers.

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African cichlids, longjaw mudsuckers, and red shiners contributed to 4%, 3%, and 2%, respectively, of the total catch from the four habitats sampled (Table 3). Large fluctuations in numbers and relative abundance were noted for these species based on habitat type and/or season (Figures 3 to 7).

A total of 324 desert pupfish were captured during the four surveys and they made up 2% of the total catch (Table 3). Moderate seasonal fluctuations in the numbers of desert pupfish sampled and their relative abundance were noted within habitat types (Figures 3 to 6). Considerable variation was even noted in relat±ve abundance figures within a specific area (e.g., three sample sites in Wheeler Drain during the fall sur~'ey, Table 1).

Crayfish and shortf in mollies accounted for 2% (276) and 1% (141) of the total catch, respectively (Table 3). Moderate seasonal fluctuations in their numbers and relative abundance were also observed within the various habitats (Figures 3 to 7), but the numbers of those species captured"was too few to be of significance.

Eight species made up the remaining 1% of the total catch from all the habitats during the quarterly surveys (Table 3). These species were the orangemouth corvina, mosquitofish, porthole fish, threadfin shad, Gulf croaker, yellow bullhead, and the bluegill (Table 3).

Surveys of San Felipe Creek

In contrast to the quarterly surveys, desert pupfish were the most abundant species in San Felipe Creek, making up 70% of the 421 fish captured (Appendix 6). Sailfin mollies constituted 26%, mosquitofish 3%, and shortfin mollies 1% of the total catch (Appendix 6). Pupfish were found along the upper 7.2 km stretch of creek in the fall and along the entfre9.7 km of permanent water in the winter. However, only areas unsampled during the fall survey were sampled during the winter (Figure 2).

The ratios of potential predator and competitor species to desert pupfish were highly variable from one area of the creek to another (Table 4), as they were in the irrigation drains ranging from 8:1 to 1:27 (Table 4).

Refugia Populations 

Desert pupfish populations within refugia were not sampled during the Salton Sea and San Felipe Creek surveys, however, information concerning their location, date of establishment, number of fish introduced, and size should be noted. 

The first refugium established was at Palm Canyon, San Diego County. within Anza-Borrego Desert State Park. Fifty desert pupfish from the Salton Sea were introduced in June 1970 into a 60' x 15' x 3' concrete pond.

 

FIGURE 7. Seasonal distribution of species captured from all habitats sampled during desert pupflsh surveys al the Salton Sea. Numbers above the bar refer to total nurmber captured. A = sailfin mollies, B = red shiners, C = crayfish, D = longjaw mudsuckers, E = desert pupfish

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TABLE 3. Numbers and Percent Composition of Each Species Captured From All Habitats During Quarterly Desert Pupfish Surveys at the Salton Sea.

Common name

Scientific name

Number
Percent

Sailfin molly

Poecilia latapinna

13,693

85

African cichlids

Tilapia/Sarotherodon sp.

641

4

Lonjaw mudsucker

Gilichthys mirabilis

500

3

Red shiner

Notropis Lutrensis

399

2

Desert pupfish

Cyprinodon macularius

324

2

Crayfish

Procambarus clarkii

276

2

Shortfin molly

Poecilia mexicana

141

1

Orangemouth corvina

Cynoscion xanthulus

25

>1

Mosquitofish

Gambusia affinis

22

>1

Porthole fish

Poeciliopsis gracilis

16

>1

Carp

Cyprinus carpio

3

>1

Threadfin shad

Dorosorma petenense

3

>1

Gulf croaker

Bairdiella icistia

2

>1

Yellow bullhead

Ectalurus natalis

2

>1

Bluegill

Lepomis macrochirus

1

>1

16,048

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TABLE 4. The Ratios of Potential Predator and Competitor Species to Desert Pupfish in Individual Traps Within San Felipe Creek During the Fall Survey.

Number
predators/competitors
Number
pupfish
Ratio of predators/competitors to desert pupfish
15
2
8:1
49
10
5:1
5
3
5:3
11
10
1:1
8
16
1:2
2
6
1:3
23
93
1:4
2
27
1:14
1
27
1:27

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Forty desert pupfish were introduced into a 10' x 2' circular concrete pond at the Living Desert Reserve, Riverside County, during 1972. These fish originated from the refugium population at Palm Canyon and were introduced by Department personnel.

Another refugium was established in September 1975 in Arrowweed Spring (Imperial County), a concrete wildlife drinker. Twenty-five desert pupfish were introduced from the Salton Sea into this 10' x 10' x 3' refugium by Department personnel. A portion of this drinker is capped and only a 3' x 10' section is exposed. 

A second pupfish refugium was established in Anza-Borrego Desert State Park at Palm Spring in May 1978. Forty-five desert pupfish were introduced from the Palm Canyon Refugium to a clover-shaped concrete pond that measures roughly 20' long x 8' wide. The depth varies from a spawning shelf 8 in. deep to the remainder of the pond which is 24 in. deep. The water source for the pond is a natural spring.

The most recent refugium established was also within Anza-Borrego Desert State Park, at the Visitor Center. Thirty desert pupfish from the Salton Sea and 20 from Palm Canyon Refugium were introduced in April 1979 into an irregular-shaped concrete pond 20' long x 8' wide. The depth of the pond varies from a 4 in. deep spawning shelf to the major portion which isl8 in. deep.

Pupfish Table of Contents

DISCUSSION