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| Barradas,José R. S.; Lermen,Isabel S.; Larré,Gabriel G.; Martins,Thaís P.; Fontoura,Nelson F.. |
| ABSTRACT A weight-length relationship was established for Corydoras paleatus (Jenyns, 1842) (Siluriformes, Callichthyidae) (n=596) from samples taken in November-December 2009 and March-April 2010, in Pinguela Lagoon (29°46'57"S; 50°11'16"W), Rio Grande do Sul, Brazil. The species showed a polyphasic allometric growth pattern, each stanza described by an independent power equation controlled by a switch function: W = a1Lb1 ∙ (1 + eRsc ∙ (L-SCP))-1 + a2Lb2 ∙ [1 - (1 + eRsc ∙ (L-SCP))-1] ; where W is the expected weight for a specific length L, a1 and a2 are the proportionality coefficients for stanzas 1 and 2, b1 and b2 are the allometric coefficients for stanzas 1 and 2, Rsc is the stanza changing rate for the switch function and SCP is the stanza changing... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allometric growth; Length at first maturity; Reproduction; Sexual maturity; Length-weight relationship. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212016000100217 |
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| Souza,Jussara E. de; Fragoso-Moura,Evelise N.; Fenerich-Verani,Nelsy; Rocha,Odete; Verani,José R.. |
| The structure of Cichla kelberi population was characterized regarding the sex ratio, total length composition and some reproductive characteristics. The specimens were collected in two periods, from November 2002 to November 2003 and from December 2004 to May 2006. The sex ratio was significantly different than 1:1. The total length varied from 3.4 to 40.1 cm, with individuals in the shortest length classes occurring throughout the year, but with greater incidence in the warmer periods. Females and males reached similar lengths and there was no difference between the sexes regarding the length-weight relationship. The estimated values of condition factor were near the central value of 1.0 and decreased during the cooler months, coinciding with periods of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Condition factor; Fecundity; Length-weight relationship; Reproduction. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000200007 |
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| Araújo,Francisco Gerson; Duarte,Silvana; Goldberg,Rubens Sterental; Fichberg,Liana. |
| Parauchenipterus striatulus is a representative of the freshwater catfish with wide distribution in the South America region. Despite of being a very abundant fish in rivers and reservoirs of this region, little is known about its biology and ecology. In Ribeirão das Lajes reservoir (22º42'S - 22º50'S, 43º53'- 44º05' W, Rio de Janeiro), the Rio de Janeiro state's largest hydroelectric reservoir, this species is very abundant, representing about 40% of the total experimental fish catches using gill nets. This paper aims to assess aspects of the reproductive cycle of this species describing the gonadal stages, gonadosomatic index, weight-length relationship and condition factor. Fish sampling were carried out bi-monthly, between April 1996 and May 1997. Gill... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Auchenipteridae; Length-weight relationship; Reproduction; Condition factor; Gonadosomatic index; Reservoir. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81751999000400016 |
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| Vasconcelos,Lilian Paula; Súarez,Yzel Rondon; Lima-Junior,Sidnei Eduardo. |
| In order to describe some aspects of the population ecology of Bryconamericus stramineus in the Guiraí River basin, upper Paraná River basin, samples were taken bimonthly from October 2006 to August 2007 at seven sites in the basin. A total of 960 individuals, including 532 females, 316 males, and 112 of undetermined sex, were collected. A significant variation in the sex ratio was observed (Χ2 = 32.82; p < 0.001). Females were larger (59.7 mm) than males (58.9 mm); however, males showed a larger angular growth coefficient (b) than females. It was estimated that 50% of females were sexually mature at 36.4 mm. The highest rate of ovary development was observed in October, while in June 2007 no mature females were found. Mean fecundity was estimated at... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Length-weight relationship; Mortality; Reproductive strategy; Sex ratio. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032011000200006 |
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