title: Response of sex ratio to timing of breeding in the small cyprinid Gnathopogon caerulescens.
abstract: The influence of hatching date on the sex ratio of wild Gnathopogon caerulescens was examined. Cohorts reared from eggs collected in the early and middle parts of the spawning season showed almost balanced sex ratios, with female bias in some cohorts. Cohorts born later in the season mostly displayed male bias, and the mean proportion of males later in the season was significantly higher than in early- and mid-season cohorts. These results indicate that the sex ratio of G. caerulescens changes with the time of breeding, increasing along with the ambient water temperature of the lake.
authors.affiliation: Shiga Prefecture Fisheries Experiment Station, Hikone Shiga, 522-0057, Japan.|Lake Biwa Museum, Oroshimo 1091, Kusatsu, Shiga, 525-0001, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Fujioka
authors.affiliation: Shiga Prefecture Fisheries Experiment Station, Hikone Shiga, 522-0057, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kikko
authors.affiliation: Shiga Prefecture Fisheries Experiment Station, Hikone Shiga, 522-0057, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Saegusa
authors.affiliation: Shiga Prefecture Fisheries Experiment Station, Hikone Shiga, 522-0057, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Usuki
authors.affiliation: Lake Biwa Museum, Oroshimo 1091, Kusatsu, Shiga, 525-0001, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuka
mesh_terms: D000818:Animals; D001947:Breeding; D003530:Cyprinidae / Q000196:embryology / Q000502:physiology*; D005260:Female; D008297:Male; D012621:Seasons; D012623:Seawater / Q000737:chemistry; D019849:Sex Determination Processes; D012744:Sex Ratio; D012726:Sexual Behavior, Animal; D013696:Temperature
keywords: ESD; TSD; proportion of males; sex determination; sex ratio; water temperature