Beautiful Shiner

Cyprinella formosa

Description

The beautiful shiner, Cyprinella formosa, is a small, silvery minnow with an elliptical, compressed, elongated body that has a metallic iridescence, large eyes, large scales, and a pointed snout. Its length is 3-6 in (7.5-15 cm) in length. The belly, fins, and tail are diffused with an attractive red-orange coloration. The caudal fin is deeply notched with pointed lobes. The shiner is tan dorsally and metallic or silver laterally with some orange on the body. Breeding males are brilliantly colored, with orange or yellow fins and a bright greenish-blue body. The dorsal and anterior surfaces have a wash of yellow or orange. Females remain a drab yellowish-brown with colorless, clear, or slightly yellowed fins throughout the year. This species has also been classified as Notropis formosa.

Behavior

The male scoops a nest out of gravel in shallow, fast-flowing water, where the female deposits her eggs, probably in late spring through late summer. Life span is up to three years. The beautiful shiner feeds mostly on terrestrial and aquatic insects, augmented with algae and other plant matter.

Habitat

The beautiful shiner occurs in a variety of stream habitats, but the largest concentrations are found in the riffles of smaller streams. Aquatic habitats in the region are subject to severe drying in summer and sudden flooding in the rainy season. Streams flow intermittently during the dry season, and the shiner seeks refuge in permanent, spring-fed pools.

Distribution

This species is endemic to the Rio Yaqui basin of southeastern Arizona, northwestern Sonora, Mexico, and portions of eastern Chihuahua, Mexico. It was also found in the various closed drainages of the Guzman basin, including Rio Mimbres in New Mexico and the Casa Grandes, Santa Maria, and Del Carment, just east of the Rio Yaqui. It was first collected from San Bernardino Creek in extreme southeastern Arizona. The beautiful shiner survived in San Bernardino Creek until spring flows diminished because of groundwater pumping, and the creek dried up. Remaining habitat there was severely trampled by drinking livestock, making it uninhabitable. The water flow of the Mimbres River has been depleted by diversion and groundwater pumping. This species is now considered extirpated from the United States. Stock collected under permit from the Mexican government in 1989 from Rio Moctezuma was released in the San Bernardino National Wildlife Reserve in 1990 and survives as reproducing populations in three ponds. Contract biologists from the Arizona State University and the University of Michigan surveyed the Rio Yaqui basin in 1979 and found populations of the beautiful shiner seriously depleted in the Mexican portion of its historic range. It was found to be absent from Arizona and New Mexico.

Threats

The range and numbers of the beautiful shiner have decreased significantly because of habitat modifications, such as arroyo cutting, water diversion, dam construction, and excessive pumping of groundwater from the aquifers. Many rivers in the lowlands of Mexico, formerly inhabited by the beautiful shiner, have been modified into an artificially channeled canal system to support irrigation agriculture. This has destroyed many of the pools used by fishes to survive a drought. Water quality has declined due to chemical and sewage contamination. The beautiful shiner currently receives no legal protection from the Mexican government. Of particular danger to the beautiful shiner is the indiscriminate release into the watershed of the closely related red shiner (Notropis lutrensis ), a fish used as bait for sport fishing. The expanding population of the red shiner appears to be reducing the beautiful shiner by competition and interbreeding.

Conservation and Recovery

If sufficient habitat can be secured and maintained in the San Bernardino National Wildlife Refuge (Cochise County, Arizona) or reclaimed in the Mimbres River (Luna County, New Mexico), the beautiful shiner could be reintroduced at either place, using Mexican stock. The aquatic habitats of the wildlife refuge are considered in jeopardy because of generally lowered water tables in the region. The U. S. Bureau of Land Management (BLM) has issued leases for geothermal resources on lands adjacent to the San Bernardino National Wildlife Refuge. Biologists fear that exploration and development of these leases could cause further depletion of the underground aquifers or create channels for pollution of groundwater. The BLM will examine these threats in consultation with the U. S. Fish and Wildlife Service.

Contact

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
P.O. Box 1306
Albuquerque, New Mexico 87103-1306
Telephone: (505) 248-6911
Fax: (505) 248-6915
http://southwest.fws.gov/

References

Hendrickson, D. S., et al. 1980. "Fishes of the Rio Yaqui Basin, Mexico and United States." Journal of the Arizona-Nevada Academy of Science 15 (3): 65-106.

Miller, R. R. 1977. "Composition of the Native Fish Fauna of the Chihuahuan Desert Region." In Transactions of the Symposium on the Biological Resources of the Chihuahuan Desert Region, edited by Wauer and Riskind. Transactions of Proceedings Series No. 3. U. S. Department of the Interior, Washington, D. C.