Laserfiche WebLink
contains this dace has a sand substrate This minnow is herbivorous, feeding on as a spawning substrate. <br />along the shoreline with submerged veg- aquatic vegetation. Scott and Crossman The northern redbelly dace is a very <br />etation covering a substrate of decompos- (1973) found that this species may spawn rare fish in Colorado and should not be <br />ing material in the middle. twice during a summer using algal mats used as a bait fish. <br />Family Cyprinidae Genus Phoxinus <br />SOUTHERN REDBELLY <br />DACE <br />Phoxinus erythrogaster <br />(Rafinesque) <br />A small, round minnow; mouth ter- <br />minal and oblique, angle of the mouth <br />ranges from 48-50' from the horizontal, <br />snout relatively long; dorsal and anal fins <br />usually have 8 rays; (a study in Oklahoma <br />found a mean number of dorsal rays to be <br />10 while the mean number of anal rays <br />was 11; Hill & Jensen 1968); peritoneum <br />dark; intestine long and coiled; scales very <br />small, more than 70 in the lateral line; <br />pharyngeal teeth 0, 5-5, 0. <br />Like the northern redbelly dace, see <br />previous account. P. erythrogaster is a very <br />beautiful species. Olivaceous above with <br />dark spots on the back, there are two <br />dark, longitudinal stripes separated by a <br />cream-colored interspace. The stomach is <br />cream-colored. In much of the species, <br />range the stomach of breeding males is <br />red with yellow-tinted fins, while the space <br />between the two longitudinal stripes on <br />the side is red (Cross and Collins 1975, <br />Pflieger 1975). The stomach of breeding <br />males in Colorado remains cream- <br />colored, or at most pale orange while the <br />ventral fins are yellow. The southern <br />redbelly dace can grow to 3 inches in <br />length. <br />Range: The species is found throughout <br />the central Mississippi drainage with iso- <br />lated populations in Kansas, Oklahoma <br />and New Mexico (Koster 1957, Miller and <br />Robison 1973, Cross and Collins 1975, <br />and Pflieger, 1975). In Colorado, one pop- <br />ulation of southern redbelly dace has <br />been discovered in a single tributary of the <br />Arkansas River in Pueblo (Miller 1982). <br />This small tributary is little more than a <br />small spring which surfaces at the base of <br />a hill, flows alongside a railroad track for <br />about a half mile and then enters the <br />Arkansas River. Single individuals of the <br />southern redbelly dace have been <br />previously collected in 1965 in the Arkan- <br />sas River in Pueblo and Canon City (J. <br />Seilheimer, personal communication) and <br />by Miller (1982) in Turkey Creek in Pueblo <br />County. It is not known for certain if this <br />population is native to Colorado. Since the <br />coloration of southern redbelly dace col- <br />lected in Colorado differs from specimens <br />in other portions of the species' natural <br />range, it is possible the population is a <br />relict of the species' historic distribution <br />pattern and has been isolated from other <br />P. erythrogaster populations for many <br />decades. <br />Habitat: The single Colorado popula- <br />tion is found in a small, slow flowing, clear <br />creek with abundant algal growths cover- <br />ing a stream substrate of deep silt depos- <br />its. In addition there is abundant riparian <br />vegetation which provides shade. There <br />are very few situations like this in the <br />lower Arkansas Basin in Colorado. The <br />stream containing this species becomes <br />warm (76°F) and dissolved oxygen levels <br />can be low (1.0 parts per million) during <br />the summer. <br />The southern redbelly dace is herbi- <br />vorous and feeds mostly on microscopic <br />vegetation taken from the stream bottom <br />(Phillips 1969). In the same study, diatoms <br />were found to be the most important food <br />item, while blue-green algae, although <br />taken, were undigested. The species <br />spawns in late spring in swift, shallow rif- <br />fles over a gravel substrate or using the <br />nests of other minnow species (Cross and <br />Collins 1975). Gravid and spent females <br />were collected in late April in Colorado. <br />This beautiful species is very rare here <br />and should not be used as a bait fish. The <br />continued existence of this species in Col- <br />orado is extremely tenuous. An accidental <br />spill of any toxicant into the stream could <br />easily eliminate this population of <br />southern redbelly dace. <br />r - - - - - T - -r-l T^IT1 I <br />--J --1--- --1----------? <br />Distribution by County of the southern redbelly dace. <br />Colorado's Little Fish 22 <br />An adult southern redbelly dace.