title: Gonadossomatic relation and reproductive strategy of Brycon opalinus (Cuvier, 1819) in the Serra do Mar State Park--Núcleo Santa Virgínia, Atlantic Forest, Brazil.
abstract: The objective of this study was to analyze the gonadossomatic relation of males and females of Brycon opalinus (the Pirapitinga do Sul) in the Serra do Mar State Park--Núcleo Santa Virgínia. The study area included three rivers: Paraibuna, Ipiranga, and Grande. From the gonadossomatic relation, it was possible to determine the reproductive season and strategy of this species. The gonadossomatic relation was high throughout the year for both males and females. Sperm competition and dilution of the ejaculate in the spawning locations favored substantial development of the testicles. The sex ratio of Brycon opalinus was always in favor of females. The existence of sexual dimorphism in this species was confirmed from the larger size of the females.
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, 13506-900, Brazil. leanmg@rc.unesp.br
authors.forename: L M
authors.initials: LM
authors.lastname: Gomiero
authors.forename: F M S
authors.initials: FM
authors.lastname: Braga
mesh_terms: D000818:Animals; D001938:Brazil; D005260:Female; D005399:Fishes / Q000145:classification / Q000254:growth & development / Q000502:physiology*; D006066:Gonads / Q000254:growth & development*; D008297:Male; D012098:Reproduction / Q000502:physiology*; D045483:Rivers; D012621:Seasons; D012727:Sex Characteristics; D012741:Sexual Maturation / Q000502:physiology*