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Some Aspects of Biology of the Longfin Dace, a Cyprinid Fish Characteristic of Streams in the Sonoran Desert

1971; Southwestern Association of Naturalists; Volume: 15; Issue: 4 Linguagem: Inglês

10.2307/3670225

1943-6262

W. L. Minckley, Willard E. Barber,

Archaeology and Natural History

The longfin dace spawns over a prolonged period, December through July, in low-desert streams, utilizing saucer-shaped depressions in sandy-bottomed, shallow pools. No territoriality is evident. Females enter a nest area to be serviced by one or more males in a chase and flurry type of spawning behavior. The species is highly opportunistic, dispersing rapidly to newly flooded stream segments in periods of high runoff. It is capable of persisting for an amazing period of time in desiccating streams through various behavioral means. The longfin dace, Agosia chrysogaster Girard, is the commonest and most adaptable cyprinid native to the American Southwest (Miller, 1961; Minckley, 1965; Miller and Lowe, 1967; Lowe, et al., 1967). Its center of distribution is the Gila River basin, lower Colorado River system, from which it presumably dispersed to the Bill Williams River basin, western Arizona (Miller, 1946), and to the predominantlyMexican Rios Sonoyta (Hubbs and Miller, 1948) and Yaqui (Miller and Lowe, 1967), of northern Sonora. No specific reports have been published on the biology of this fish, but observations we have accumulated over the past seven years add to understanding of how this species persists in the extreme environments of desert streams, and form the basis for this report. REPRODUCTION. The reproductive season for Agosia is variable from year to year, but generally prolonged. At lower elevations in south and central Arizona, we have records of prolarvae of longfin dace from December through July, plus one isolated record of larval individuals in early September. Nests and reproductive behavior have been observed from February through August in various streams. Koster (1957) implied that longfin dace in New Mexico spawn in late sum1 Studies supported in part by grants from the Faculty Research Committee, Arizona State University, the Sport Fishing Institute, and the Theodore Roosevelt Fund, American Museum of Natural History.