LIFE-HISTORY AND ECOLOGY OF THE ORANGEFIN-DARTER ETHEOSTOMA-BELLUM (PISCES, PERCIDAE)

Juvenile and adult orangefin darters in the Green River system, Kentucky, were segregated mainly by water depth, current velocity and substrate type. Use of riffle habitats varied in relation to spawning activity. Sexual maturity was typically achieved at 2 yr of age, but maturity was attained by some early-hatched 1-yr-olds. Spawning was from late April to late June in gravel substrates of fast-flowing riffles. Large territorial males spawned over females buried in the gravel, and on one occasion cuckoldry was observed. Incubation time was 7-9 days at 23°C and mean total length at hatching was 6.1 mm TL. Males grew more rapidly and attained a larger size than females; maximum longevity was c36 mo. Sex ratio of males to females was 1.05:1.00. Mean density was 0.5 fish/m2 but varied seasonally. Juveniles and adults ate mainly dipteran larvae, ephemeropterans and hydracarinians but selectivity of food items varied seasonally. Diel feeding patterns were bimodal and crepuscular in summer with peak activities at 1800 h and 2400 h. -from Author