PMID: 16532189Mar 15, 2006Paper

Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba river, Maricá, RJ, Brazil

Brazilian Journal of Biology = Revista Brasleira De Biologia
R MazzoniE P Caramaschi

Abstract

Aspects of the reproductive biology of Astyanax janeiroensis in the Ubatiba river in Maricá, RJ, Brazil were evaluated in order to ascertain whether the strategy adopted by the species is causally related to environmental variables. Specimens were collected on a monthly basis from October 1994 to September 1995, through electrofishing. The Sex ratio was not significantly different from the expected frequency of 1:1 (G = 1.29; p > 0.50); nonetheless, considering three standard length classes, significantly larger numbers of females were recorded for the higher SL class (G = 11.07; p < 0.01). Size at first maturation showed no significant differences between sexes. Length-weight ratio analyses showed negative allometry for males and isometry, for females. Length structure was significantly different between sexes, suggesting that females are larger than males (D = 0.027, p < 0.01). Reproductive specimens were recorded during nine months of the annual cycle. Seasonal variations of reproductive specimens belonging to two different standard length classes displayed an asynchronous behavior, with larger specimens having a longer reproductive period and smaller ones reproducing for fewer months during the annual cycle. High values of ...Continue Reading

References

Mar 1, 1976·The Quarterly Review of Biology·S C Stearns
May 21, 1982·Journal of Theoretical Biology·G A Parker
Jan 18, 2003·Brazilian Journal of Biology = Revista Brasleira De Biologia·R MazzoniN Fenerich-Verani

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Citations

Aug 13, 2011·Ecotoxicology and Environmental Safety·Paula S PradoElizete Rizzo
Feb 19, 2008·Brazilian Journal of Biology = Revista Brasleira De Biologia·R Mazzoni, R Iglesias-Rios
Dec 3, 2015·Anais Da Academia Brasileira De Ciências·Ursulla P SouzaFrancisco M S Braga
Nov 14, 2018·Zygote : the Biology of Gametes and Early Embryos·Nivaldo Ferreira do NascimentoGeorge Shigueki Yasui

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