The Reproductive Biology of the Southern Redbelly Dace, Chrosomus erythrogaster Rafinesque, in a Spring-Fed Stream in Kentucky

Abstract

The reproductive biology of the southern redbelly dace, Chrosomus erythrogaster Rafinesque, was studied in Ivy Creek, Warren Co., Kentucky, from 1971 to 1972. Reproduction occurred from midApril through June. Older adults spawned in April and May, early in the reproductive period, while younger adults, in the latter part of their 1st year of life, spawned during May and June. Age Group 0 specimens represented the majority of the reproductive population. The number of mature eggs per female ranged from 140 681 (x = 316). Ova diameter exhibited an inverse relationship with standard length, while a positive correlation existed between number of mature eggs and standard length. Differences between the sexes were marked and included intensity and distribution of pigmentation, breeding tubercle development and length and shape of the pectoral fins. Males were most distinctive, having prominent scarlet ventral surfaces and breeding tubercles on the head and fins during the reproductive period. Males had longer and broader pectoral fins. No significant deviation from a 1:1 sex ratio was observed.