Desert Scientific Name: Springs – elegans, – Cyprinodon bovinus, – Gambusia nobilis, Gambusia – Gambusia gaigei Federal Status: All Endangered; 3/11/67, 8/15/80, 10/13/70, and 3/11/67, respectively • State Status: All Endangered

Description of At present, the species occurs pri- and Species, Habitats, and marily in aquatic habitat fed by Present range for spring flow from Giffin, and San Pecos Gambusia Life History Solomon springs near Balmorhea, pupfish . The population at Phantom The Lake Springs has been almost totally seldom exceeds 2 inches in total lost due to loss of length. It is gray-green above and spring flow. The pale yellow to white below, with clear areas of greatest to light orange fins. The sides are sil- abundance are in very white with blue-black blotches Balmorhea State forming a “stripe” along the side Park in the (often faint on the male). Males have refugium canal Present range for black speckling on the side and a (constructed in Comanche Springs Pupfish black edge on the caudal (tail) fin. 1974) and in San Present range for In contrast to other Cyprinodon Solomon Ciénega Leon Springs Pupfish species, this pupfish has a slender (created in 1996). Present range for body and lacks vertical bars. Additional habitat consists mostly of a system of concrete and earthen irri- grayish-brown on top, and lighter gation canals. The pupfish are often below. abundant in earthen ditches and con- The Leon Springs pupfish was crete flumes 4 inches or more deep first discovered in 1851 by members with bottoms covered with debris of the U.S. and Mexican Boundary and vegetation, such as muskgrass Survey. The was originally found (Chara spp.). They are rarely found at Leon Springs, a spring system that in concrete flumes where water depth once flowed in the Leon Creek is less than 4 inches and/or the bot- drainage about 6 miles west of Fort tom is scoured of debris. Stockton in Pecos County. Its historic Comanche Springs Pupfish The Comanche Springs pupfish range probably included all permanent © J.E. Johnson is known only from freshwater to waters within Leon Creek and the slightly saline habitats. The springs associated springs. In 1918, the area near Balmorhea have low salinities, where the fish was first collected was as did the now dry Comanche inundated by Lake Leon, an irrigation Springs. Other species of pupfish in and fishing impoundment. By 1938, the system inhabit more the Leon Springs pupfish could no saline waters. Breeding is thought to longer be found in the area where it occur during most months of the was first discovered. Although Leon year, and spawning (egg-laying) Springs once produced a flow of about occurs in areas of flowing water as 20 cfs (cubic feet per second), the well as in stagnant pools. In irriga- springs produced no measurable flow tion canals, the pupfish prefer shal- by 1958 due to pumping Leon Springs Pupfish low areas with low current velocities. © TPWD in excess of recharge. Although they feed mostly on the bot- From 1958 until 1965, the Leon Historically, this pupfish tom, they also feed at the surface and Springs pupfish was thought to be occurred in two separate spring sys- at other levels in the water column. extinct. The fish were rediscovered tems of the Pecos River drainage. in 1965, when they were collected One was Comanche Springs, with Leon Springs pupfish from Diamond Y Spring, located headwaters (now almost always dry) The Leon Springs pupfish is a about 10 miles north of Fort within the city limits of Fort small (about 2 inches), robust pup- Stockton. The fish have since been Stockton, Texas, and the other was a fish, with a wider head and body found in Leon Creek, downstream group of springs near Balmorhea. than most pupfish. Breeding males from Diamond Y Spring in waters The pupfish population at Comanche are powdery blue-gray with fins of Springs were extirpated (lost) when varying shades of yellow edged with the springs first went dry in 1955. black. Females are grayish-yellow or Spring Fishes 1 that are quite saline. The recent used for internal fertilization of localities are about 15 miles down- the female. from where the fish was origi- Historically, the Pecos gambusia nally found. was restricted to the Pecos River The Leon Springs pupfish basin in southeastern presently occurs within two 3-mile and western Texas. The species spring-fed segments of Leon Creek occurred from as far south as Fort and Diamond Y Spring. Diamond Y Stockton, Texas to as far north as Draw is a to Leon Creek. Fort Sumner, New Mexico. The popu- Pecos Gambusia These spring-fed segments are sepa- lations of Pecos gambusia that once © Dave Schleser rated by about one mile of usually existed at Leon Springs and dry stream bed. The fish prefer Comanche Springs were lost when slow-flowing stretches of water, with these springs went dry during the a substrate of mud and aquatic plant mid-1950s. Presently in Texas, popu- roots. They are also abundant in lations of the Pecos gambusia occur natural spring-fed marshes (ciéne- near Balmorhea in aquatic habitat gas), channels, and pools along this supported by spring flow from watercourse. Phantom Lake, Giffin, San Solomon, The Leon Springs pupfish feeds and East Sandia springs. The largest primarily on the bottom, ingesting population is in San Solomon Ciénega Big Bend Gambusia large amounts of detritus (decom- at . A substan- © TPWD posed organic material) and mud. tial population also occurs in Leon Food items include , algae, Creek and in Diamond Y Spring out- The Pecos gambusia is an oppor- and small invertebrates. “Pit dig- flow north of Fort Stockton. The tunistic feeder. Primarily a surface ging” has been observed, where the species also occurs in a limited num- feeder, major food items include fish (mostly males) rest on the bot- ber of locations in New Mexico. insects, other small invertebrates, and tom of the pool and undulate their The Pecos gambusia occurs abun- some filamentous algae. bodies to churn up the substrate. dantly in spring-fed pools, spring Competition with other This behavior is thought to be associ- runs, and downstream areas having Gambusia species is important in ated with locating buried food items. relatively constant temperatures, determining the relative abundance The Leon Springs pupfish abundant overhead cover, sedge-cov- of the Pecos gambusia. Studies have spawns throughout the year, with ered marshes, and in gypsum sink- shown that, over a period of years, females laying up to 10 eggs per day. holes with no surface flow. It is the western outcom- Spawning occurs on the bottom sub- capable of occupying a variety of petes the Pecos gambusia in isolated strate in territories aggressively habitats if factors such as tempera- pools and downstream waters well defended by individual males. ture and salinity are suitable. removed from spring influence. Shallow shelf areas with slow cur- The closest relatives of the Pecos Salinity seems to be important in rents, warmer than the deeper chan- gambusia are found in south Texas determining the influence of an nels, are preferred for spawning. and Mexico, so the species has a long introduced competitor, the large- This species is known to tolerate an history of adaptation to warmer cli- spring gambusia (Gambusia geiseri). unusually wide range of salinities and mates. The fish does not occur even Since the Pecos gambusia is tolerant temperatures. However, studies sug- in spring-fed waters at higher eleva- of a wide range of salinities, it can gest that the temperature range tions, presumably because water tem- outcompete the largespring gambusia required for successful reproduction peratures are too cold. Maximum in the saline waters of Leon Creek, may be quite narrow. The extended temperature is also important in while the largespring gambusia seems breeding season, wide salinity and determining suitable habitat. The competitively superior in the freshwa- temperature tolerances, and broad Pecos gambusia seems to be less toler- ters of the Balmorhea area. In areas food habits suggest that the Leon ant of variable temperatures than the where the two species are found Springs pupfish is a generalist that western mosquitofish (Gambusia affi- together, the Pecos gambusia inhabits does best in simple communities with nis), a major competitor. Studies indi- mid-water and bottom habitats and few competing species. cate that the Pecos gambusia is more the largepring gambusia is more abundant in spring-fed waters, but it often found at the surface near vege- Pecos gambusia may also do well in less spring-like tation. The Pecos gambusia is a small waters if there is enough cover from 1 (1 /2 inches long), live-bearing fish above to buffer temperature changes. Big Bend gambusia with a dark lateral stripe and a metal- Predation by green sunfish The Big Bend gambusia lic gray-blue color. Females have a (Lepomis cyanellus) and largemouth (Gambusia gaigei) is a small, live- black area on the abdomen that sur- bass ( salmoides) can bearing fish which reaches a maxi- rounds the anal fin and anus. The 1 become a major limiting factor in mum length of about 1 /2 inches. anal fin of males is modified into a areas where there is no submerged The fish is yellowish in color, with a gonopodium, a tube-like structure vegetation or enough shallow water faint lateral stripe and orange to yel- to provide protection from predators. low dorsal and anal fins. Other Females produce up to 40 young markings include a bar beneath the 2 Desert Spring Fishes every 4 to 5 days. eye, and a faint, dark chin bar. Males lation include competition with the Texas, more water is being with- western mosquitofish and lack of drawn from by pumping thermal stability. All present popula- than is being replaced by rainfall. In tions of Big Bend gambusia consist of addition, surface waters are being descendants of three fish (two males diverted from aquifer recharge zones. and one female) taken from the This continued of aquifers declining Village popula- could eventually cause the demise of tion in 1956. The fish are now being spring systems throughout west maintained in a refugium pond Texas, and with them the located in Big Bend . of a whole array of unique fishes and Small populations also exist at the aquatic plants and . This Diamond-Y Spring © TPWD Dexter National Fish Hatchery and would also have serious consequences Technology Center in New Mexico. for Texans of the Trans-Pecos, who The habitats originally occupied would lose a valuable water supply. by the Big Bend gambusia were marshes and natural pools, with Recovery Efforts clear, shallow water fed by warm Research is ongoing to better under- springs. Dense aquatic vegetation stand the life history, habitat require- presumably occurred in these areas. ments, and limiting factors affecting Although the present refugium has the endangered fishes of . open water in excess of 3 feet, the Continued monitoring of endangered Big Bend gambusia are most abun- fish populations and habitat is very dant among the cattails and important. muskgrass near the shore. A man-made, but biologically The Big Bend gambusia preys A spring-fed creek in Big Bend State Natural Area functional desert ciénega or marsh at © Matt Wagner on aquatic invertebrates. Little is Balmorhea State Park has been estab- known concerning factors limiting lished and the endangered fishes are reproduction in this species, but tem- prospering in this new refugium. perature, daylight hours, and food This project, sponsored by Texas availability are known to affect repro- Parks and Wildlife Department, the ductive success in related species. Educational Foundation of America, Competition with the western mos- and the National Fish and Wildlife quitofish is thought to be a major fac- Foundation, not only creates habitat tor affecting the survival of the Big for the Comanche Springs pupfish Bend gambusia. and the Pecos gambusia, but also pro- vides spring-fed habitat for a wide Threats and Reasons variety of native plants and animals. for Decline It is an excellent opportunity for The major threats to the survival of school children and park visitors to Phantom Lake cienega and spring © TPWD Andrew Price the desert spring fishes are habitat learn about this unique ecosystem. loss from declining springflows and A refugium canal within the are smaller than females, and as with reduced surface waters, competition Balmorhea State Park supports sev- other gambusia species, the male’s with introduced species, and loss of eral thousand Comanche Springs pup- anal fin is modified into a tube-like genetic integrity due to hybridization fish and Pecos gambusia. A similar gonopodium for fertilizing the female. with introduced species. refugium canal, constructed by the The Big Bend gambusia is known Introductions of fish and mol- Bureau of Reclamation, was com- only from spring habitats in the lusk species from inland rivers, the pleted at Phantom Lake Spring. This vicinity of Boquillas Crossing and Rio Gulf Coast, and other sources pose a canal supported abundant, healthy Grande Village in Big Bend National serious threat to these fishes. Almost populations of these fishes. However, Park. Historically, the fish may have any co-occurring species of fish, the refugium failed when the spring existed in other springs in the vicin- either indigenous or introduced, flow declined in the late 1990s. ity of Rio Grande Village. The popu- would potentially exert some compet- In 1990, The Nature lation at Boquillas Spring (located itive pressure on populations of these Conservancy of Texas purchased the about 660 ft. north of Boquillas fishes. Competition with introduced land encompassing Diamond Y Crossing) became extinct when spring species that are ecologically similar Spring, and the portion of Leon flow ceased in 1954. The population poses an especially serious threat. Creek designated as critical habitat at the spring located near Rio Grande Large artesian springs, such as for the Leon Springs pupfish. In the Village drastically declined between those in the Balmorhea area, are 1970s, a portion of Leon Creek was 1954 and 1956, after the spring out- diminishing in flow. Phantom Lake renovated, significantly reducing the flow was altered to provide a fishing Spring, near Balmorhea, is particu- problems of competition and pool for the park campground. The larly vulnerable because it is at a hybridization. Future scientific man- Big Bend gambusia was extirpated higher elevation and thus was the from this location by 1960. Two pos- first of these larger springs to stop sible factors in the loss of this popu- flowing. In many parts of west Desert Spring Fishes 3 agement of this habitat will provide resulted from people releasing non- protection for the Pecos gambusia as native fishes (especially by emptying well as the Leon Springs pupfish. bait buckets or releasing aquarium A small population of Comanche fish) into and springs, or Springs pupfish is held at the intentionally releasing fish into state National Fish Hatchery in Uvalde, waters in an effort to improve fish- Texas. Likewise, small populations of ing. Texas Parks and Wildlife regula- Big Bend gambusia and Leon Springs tions restrict these activities. pupfish are being held at the Dexter Be careful with the application National Fish Hatchery in New of pesticides (insecticides and herbi- Mexico. These populations provide cides) and other agricultural chemi- an opportunity for researchers to cals. Improper use of chemicals can Phantom Lake canal and refugium obtain specimens for study without have devastating effects on aquatic © USFWS Ruth Stanford affecting wild populations, and pro- systems. Always follow label precau- vide stocks for reintroductions in the tions carefully, including instructions event of the loss of a population. concerning proper disposal of rinse water and containers. Check with the Where To See The Texas Department of Agriculture Desert Spring Fishes (TDA) for information concerning The best places to see and learn more proper use of herbicides and pesti- about these fishes are Balmorhea cides and licensing requirements. State Park and Big Bend National Due to the toxicity of some pesti- Park. At Balmorhea State Park, visi- cides to aquatic life, special manage- tors can cool off in the world’s ment methods are needed for certain largest spring-fed swimming pool, chemicals to help prevent possible where the Comanche Springs pupfish harm to protected species. Local rep- and the Pecos gambusia can some- resentatives of wildlife, agriculture, Biologists using a seine net to sample fish in Leon Creek times be seen hiding in the shallow, and conservation groups are working © Gary Garrett grassy areas of the pool. Also, the with landowners to develop measures two refugia at Balmorhea State Park that will allow normal agricultural spring-fed creeks and marshes. These are excellent places to observe these production to coexist with the desert precious water resources provide fish. A refugium pond near the Rio fishes. Farmers, ranchers, and pesti- unique areas of plant and life. Grande Village Campground in Big cide applicators can contact their Their protection is vital to the diver- Bend National Park offers visitors a local county extension agent, or sity of life which they support. chance to see the Big Bend gambusia Coordinator, Finally, you can support the and its habitat. Pesticide Protection, Texas Special Nongame and Endangered Department of Agriculture in Austin Species Conservation Fund by pur- How You Can Help (512-463-7476) to find out about cur- chasing a stamp, available at the Do what you can as an individual to rent recommendations in your area. Texas Parks and Wildlife Department conserve water. Comanche Springs, A portion of the remaining habi- headquarters in Austin or at most Leon Springs and others have gone tat for the Comanche Springs pupfish state parks. Part of the proceeds dry because more water is being used and Pecos gambusia consists of the from the sale of these items is used than is replaced by rainfall. When irrigation canals in the Balmorhea- to provide information to park visi- springs dry up, a whole host of plant Toyahvale area of Reeves and Jeff tors concerning endangered species. and animal life disappears with them. Davis counties. Conservation of Texas Parks and Wildlife also offers a The competition for water has taken these two endangered fishes can be wildlife conservation license plate a toll on the wetland plants and ani- enhanced by ensuring that water featuring the Texas Horned Lizard, mals of west Texas. The existence of quality in the canals supports a func- which benefits wildlife diversity these endangered fishes, and other tional aquatic community. Farmers efforts in Texas. The Conservation aquatic animals and plants which can help by careful handling of all “Keep Texas Wild” (Horned Lizard) share their habitat, depends on the fuels, oils, and hydraulic fluids so plate costs just $25 in addition to reg- continued flow of the springs near that canals are not contaminated. ular vehicle registration fees, with Balmorhea, Leon Creek, and in Big Also, maintaining a water depth $20 used to support conservation of Bend. Conservation of these spring greater than 1 foot in canals occupied wildlife diversity and habitat in ecosystems will result in the contin- by these fishes is desirable. Texas. ued ability to use water in areas West Texas landowners with downstream from their habitats. springs and associated surface water For More Information Since introduced species are a resources can provide additional pro- Contact major threat to these endangered tection to various populations of rare Texas Parks and Wildlife Department fishes, never release any fish into nat- fishes by limiting habitat disruption, Wildlife Diversity Branch ural waters. Serious problems have preventing introduction of exotic 4200 Smith School Road species, and implementing conserva- Austin, Texas 78744 tion measures designed to maintain (512) 912-7011 or (800) 792-1112 4 Desert Spring Fishes spring flow and water quality in or U.S. Fish and Wildlife Service Ecological Services Field Office 10711 Burnet Road, Suite 200 Austin, Texas 78758 (512) 490-0057 or Texas Department of Agriculture P.O. Box 12847 Austin, Texas 78711 (512) 463-7476

References Hubbs, C., R.J. Edwards, and G.P. Garrett. 1991. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. The Texas Journal of Science, suppl., Vol. 43, No. 4. 56 pp. Page, L.M. and B.M. Burr. 1991. A field guide to freshwater fishes. The Peterson Field Guide Series. Houghton Mifflin Company, Boston, MA. 432 pp. U.S. Fish and Wildlife Service. 1980. Comanche Springs Pupfish (Cyprinodon elegans) recovery plan. USFWS, Albuquerque, New Mexico. 25 pp. U.S. Fish and Wildlife Service. 1985. Leon Springs Pupfish (Cyprinodon bovinus) recovery plan. USFWS, Albuquerque, New Mexico. 26 pp. U.S. Fish and Wildlife Service. 1982. Pecos Gambusia (Gambusia nobilis) recovery plan. USFWS, Albuquerque, New Mexico. 41 pp. U.S. Fish and Wildlife Service. 1984. Big Bend Gambusia (Gambusia gaigei) recovery plan. USFWS, Albuquerque, New Mexico. 43 pp.

Funds for the production of this leaflet were provided by the U.S. Fish and Wildlife Service, under Section 6 of the Endangered Species Act.

Desert Spring Fishes 5