Reproduction, Fecundity, Sexual Dimorphism and Sex Ratio of Etheostoma fonticola (Osteichthyes: Percidae)

Abstract

Etheostoma fonticola is an endangered species of fish which spawns year-round in the relatively constant temperature headwaters of the San Marcos River and in Spring Lake (impounded origin of the river), Hays Co., Texas. However, the species appears to have two spawning peaks, one in August and the other in late winter to early spring. Proposed explanations for this observed spawning periodicity are a slight increase in water temperature and/or a decrease in flow. Ripe ovaries of preserved Etheostoma fonticola contain three distinct classes of ova based on their size and appearance. The number of mature ova (Size Group I) is positively correlated with total length of the fish while the mean diameter of mature ova is not positively correlated. Etheostoma fonticola provides no parental care to the ova and has very low fecundity (mean fecundity was 19). Sexual dimorphism is evident in the shape and size of the genital papillae and the pelvic fins and in the intensity of body coloration. The sex ratio of Etheostoma fonticola is 1.39:1.00 (M:F).