Longfin Dace - Illustration by Bill Singleton

Longfin Dace
Agosia chrysogaster

 

This fish is among the hardiest of native fish. The longfin dace is a small (less than 4 inches long) silvery minnow with a dark back and white on the belly. A dark band will sometimes be located along the sides just above the mid-section and iridescent gold flecks may develop on the upper sides of both sexes. Breeding males have some yellow on the lower parts of their paired fins.

Habitat: Longfin dace tend to occupy relatively small streams. The range of habitat is widespread, from intermittent low-desert streams to clear and cool brooks at higher elevations.

Range: Longfin dace are native to the Gila, Bill Williams, Yaqui, Magdelena and Sonotya drainages. These fish have been introduced into the Virgin River basin in Arizona and the Zuni River, Mimbres River and Rio Grande Basin in New Mexico. These fish are highly opportunistic, moving rapidly through flowing water during periods of high runoff and travelling amazing distances in a relatively short amount of time.1

Biology: "It has a remarkable capability to disperse into new habitats, appearing a few hours or days after flow reestablishes in formerly dry stream channels. Longfin dace were once recorded to survive in tiny volumes of water beneath mats of filamentous algae, then reproduce a few days after when summer rain rejuvenated the stream."2

Reproduction: Longfin dace may spawn throughout the year, but primarily in the spring. In the Colorado River Basin, longfin dace create saucer-shaped depressions where the eggs are deposited and newly hatched young. This fish is among the hardiest of native fish. The longfin dace is a small (less than 4 inches long) silvery minnow with a dark back and white on the belly. A dark band will sometimes be located along the sides just above the midsection and iridescent gold flecks may develop on the upper sides of both sexes. Breeding males have some yellow on the lower parts of their paired fins for a brief time.2

Diet: Longfin dace are omnivorous, feeding on various aquatic invertebrates and plants depending on the availability.

Status: Currently, the longfin dace is considered by the U.S. Fish and Wildlife Service (USFWS) as a "Species of Concern."3 The term "Species of Concern" should be considered as a term-of-art that describes the entire realm of taxa whose conservation status may be of concern to the USFWS, but does not have any official status.

Longfin Dace in Pima County: Currently, longfin dace are known to occur in Pima County along the perennial waters of Cienega Creek, Buehman Canyon (near the San Pedro River), and the upper reach of the Cañada del Oro. Historically, this fish occurred all along the Santa Cruz River from Santa Cruz County to the Pinal County Line (Minckley, 1973). Longfin dace disappeared from the Santa Cruz River near Tucson by 1950.4


References:

1. Minckley, W. L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix. pp. 126-128

2. Rinne, J. L. and W. L. Minckley. 1991. Native fishes of arid lands: a dwindling resource of the desert southwest. U.S. Department of Agriculture, Forest Service, General Technical Report RM-206. Rocky Mountain Forest and Range Experiment Station, Fort Collins, Colorado. pp. 17-18.

3. Arizona Game and Fish Department. Unpublished Abstract, Heritage Data Management System. April 1999

4. Zander, M. and Jennings M. 1986. Site Specific Water Quality Criteria Study for the Santa Cruz River. Harding Lawson Associates. Job No. 17,144,010.01. p. 73


back to Priority Vulnerable Species Fact Sheets