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| Freitas,Tiago Magalhães da Silva; Almeida,Vitor Hudson da Consolação; Montag,Luciano Fogaça de Assis; Rocha,Rossineide Martins da; Fontoura,Nelson Ferreira. |
| The aim of the present study was to evaluate the seasonal pattern of the gonadosomatic index (GSI), condition factor (K), and sex ratio in the catfish Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) as an approach to identify its reproductive period. A total of 589 A. longimanus specimens (251 males and 338 females) were captured in the rivers of the Caxiuanã National Forest, in the Brazilian state of Pará, between July, 2008 and July, 2009. Among the male specimens, 171 were classified as adults and 80 as juveniles, while there were 249 adults and 89 juvenile females. Using a sinusoidal equation, analysis of the GSI revealed a reproductive asynchrony between the genders, with males attaining their highest GSI values in January, while females... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Auchenipterichthys longimanus; Hydrological seasons; Reproduction; Siluriformes. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252011000400015 |
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| Oliveira,Valéria de Albuquerque; Fontoura,Nelson Ferreira; Montag,Luciano Fogaça de Assis. |
| The present study analyzed the length-weight relationship and some aspects of the reproductive biology of Anableps anableps from the mouth of the Maracanã River, in the Brazilian state of Pará. The specimens were collected using two 30 m-long gillnets with 15 and 20 mm mesh size, as well as a 1 m-diameter hand net with a 10 mm mesh. A total of 865 specimens were collected, from which an adult sex ratio of 2.12 females per male was recorded (χ² = 13.07; p<0.05). Females presented positively allometric growth, whereas males were negatively allometric. In the additional analyses, the gonads of 371 female specimens were observed microscopically. Gonadal development was classified in three stages: immature (5.0%), maturing (12.0%), and mature (83.0%).... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: "Four-eyed" fish; Reproduction; Viviparity. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252011000400007 |
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| Fontoura,Nelson Ferreira; Ceni,Gianfranco; Braun,Aloisio Sirangelo; Marques,Camilla da Silva. |
| ABSTRACT This contribution records the reproductive periods of ten dominant freshwater fish species from the Patos Lagoon and Guaíba Lake (Astyanax fasciatus, Cyphocharax voga, Hoplias malabaricus, Oligosarcus jenynsii, Oligosarcus robustus, Hoplosternum littorale, Loricariichthys anus, Parapimelodus nigribarbis, Trachelyopterus lucenai, Pachyurus bonariensis). Data were derived from monthly samples in Casamento Lake (northern Patos Lagoon; Nov. 2002 to Apr. 2004) and Guaíba Lake (Jun. 2005 to May 2006). The reproductive period was determined according to the monthly variation of the gonadosomatic index (GSI). Fish reproduction was identified during all months of the year. Oligosarcus jenynsii started reproduction in winter, but extended spawning to spring... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: GSI; Maturation; Maturity Criteria; Reproductive Cycle. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252018000200210 |
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