Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil
Autor(a) principal: | |
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Data de Publicação: | 2005 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Brazilian Journal of Biology |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842005000400012 |
Resumo: | 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 fecundity (F), varying from 3169 to 18714 oocytes, were recorded for fish of 9.1 and 10.2 cm lengths, respectively. The correlation between weight and number of oocytes/unit of weight was positive, indicating that larger specimens produced more eggs. |
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Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazilstream-dwelling fishcoastal streamreproductive biologyAspects 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 fecundity (F), varying from 3169 to 18714 oocytes, were recorded for fish of 9.1 and 10.2 cm lengths, respectively. The correlation between weight and number of oocytes/unit of weight was positive, indicating that larger specimens produced more eggs.Instituto Internacional de Ecologia2005-11-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842005000400012Brazilian Journal of Biology v.65 n.4 2005reponame:Brazilian Journal of Biologyinstname:Instituto Internacional de Ecologia (IIE)instacron:IIE10.1590/S1519-69842005000400012info:eu-repo/semantics/openAccessMazzoni,R.Mendonça,R. S.Caramaschi,E. P.eng2006-03-06T00:00:00Zoai:scielo:S1519-69842005000400012Revistahttps://www.scielo.br/j/bjb/https://old.scielo.br/oai/scielo-oai.phpbjb@bjb.com.br||bjb@bjb.com.br1678-43751519-6984opendoar:2006-03-06T00:00Brazilian Journal of Biology - Instituto Internacional de Ecologia (IIE)false |
dc.title.none.fl_str_mv |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
title |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
spellingShingle |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil Mazzoni,R. stream-dwelling fish coastal stream reproductive biology |
title_short |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
title_full |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
title_fullStr |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
title_full_unstemmed |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
title_sort |
Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil |
author |
Mazzoni,R. |
author_facet |
Mazzoni,R. Mendonça,R. S. Caramaschi,E. P. |
author_role |
author |
author2 |
Mendonça,R. S. Caramaschi,E. P. |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Mazzoni,R. Mendonça,R. S. Caramaschi,E. P. |
dc.subject.por.fl_str_mv |
stream-dwelling fish coastal stream reproductive biology |
topic |
stream-dwelling fish coastal stream reproductive biology |
description |
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 fecundity (F), varying from 3169 to 18714 oocytes, were recorded for fish of 9.1 and 10.2 cm lengths, respectively. The correlation between weight and number of oocytes/unit of weight was positive, indicating that larger specimens produced more eggs. |
publishDate |
2005 |
dc.date.none.fl_str_mv |
2005-11-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842005000400012 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1519-69842005000400012 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S1519-69842005000400012 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Instituto Internacional de Ecologia |
publisher.none.fl_str_mv |
Instituto Internacional de Ecologia |
dc.source.none.fl_str_mv |
Brazilian Journal of Biology v.65 n.4 2005 reponame:Brazilian Journal of Biology instname:Instituto Internacional de Ecologia (IIE) instacron:IIE |
instname_str |
Instituto Internacional de Ecologia (IIE) |
instacron_str |
IIE |
institution |
IIE |
reponame_str |
Brazilian Journal of Biology |
collection |
Brazilian Journal of Biology |
repository.name.fl_str_mv |
Brazilian Journal of Biology - Instituto Internacional de Ecologia (IIE) |
repository.mail.fl_str_mv |
bjb@bjb.com.br||bjb@bjb.com.br |
_version_ |
1752129875611746304 |