Abstract
Comparative study on the distribution of six species of bitterling in a creek in Fukuoka Prefecture was carried out. The upper part of the creek was fluvial, and the lower part stagnant. Acheilognathus lanceolatus, A. tabira subsp.(b) of Nakamura (1969), A. rhombeus and Rhodeus atremius showed wide distribution in the creek throughout their life. A. limbatus seemed to be a fluvial species, and R. ocellatus smithii a lentic species. In the spawning season, however, all the species of bitterling, excepting R. o. smithii, probably possess a common spawning ground in which mussels occur at a relatively high density. Adult females of A. lanceolatus, A. tabira subsp.(b) and R. atremius without ripe eggs aggregated in the lower, stagnant parts of the creek. Most juveniles of these species and of A. rhombeus seemed to grow in the lower part of the creek, and then migrate upward untill their spawning season. No species among the same phylogenetic group has the same set of the life modes (spawning season, spawning sites, aggregation of females without ripe eggs in the lower part of the creek and probability of upstream migration of 0-year-old fish toward spawning sites).
