Fator de condição gonadal, índice hepatossomático e recrutamento como indicadores do período de reprodução de Loricariichthys platymetopon (Osteichthyes, Loricariidae), bacia do rio Uruguai médio, sul do Brasil

Abstract

The recruitment period of Locariichthys platymetopon (Isbrucker & Nijssen, 1979) was investigated. It has been found out, through the data analysis, that the gonadal condition factor is a good indicator of the reproductive period and that the hepatossomatic index is probably related to the storage of reservation for the winter period. The recruitment occurred in November coinciding with the reproductive activity of May.

Morphological aspects of the ovaries of turtle Kinosternon scorpioides raised in captivity

“…In ϐishes, this factor has been used to determine the reproductive phase. High gonadossomatic indexes would indicate active vitellogenesis which means that the animal is under reproductive period (Querol et al 2002). This determination was not achievable in the animals of the present study due to the absence of alterations between the two periods, fact that would indicate that the jurara went through similar reproductive phase, the vitellogenesis.…”

Population structure and reproductive biology of Loricariichthys melanocheilus Reis & Pereira, 2000 (Siluriformes: Loricariidae) in the rio Ibicuí, Brazil

“…However, in subtropical regions, the breeding season of fish seems to be more influenced by temperature and photoperiod than by rainfall, because there are not well defined periods of drought and flood in subtropical regions, compared to tropical ones (Vazzoler & Menezes, 1992). Thus, the breeding season of Loricariichthys melanocheilus in the rio Ibicuí is strongly influenced by increased temperature and photoperiod, but it was not associated with the increase in river level, a feature also found for several species studied in Rio Grande do Sul, such as Serrapinus calliurus (Boulenger, 1900) (Gelain et al, 1999), Cheirodon ibicuhiensis Eigenmann, 1915 (Oliveira et al, 2002), L. platymetopon (Querol et al, 2002), Bryconamericus iheringii (Boulenger, 1887) and B. stramineus Eigenmann, 1908(Lampert et al, 2004. Something that is worth of notice is the large amount of specimens collected in the lake of point 1, located in the upper stretch of the rio Ibicuí in the breeding season, and a low number of specimens collected at point 3 in the lower stretch of the river.…”

“…Studies conducted on the genus Loricariichthys have focused primarily on L. anus (Valenciennes, 1835), L. platymetopon Isbrücker & Nijssen, 1979(Tos et al, 1997Querol et al, 2002;Marcucci et al, 2005;Bailly et al, 2011) and L. spixii (Steindachner 1881) (Duarte & Araújo, 2001). So far, there is no record in the literature of studies addressing aspects of the biology of Loricariichthys melanocheilus, probably because it is a recently described species and is not widely distributed along several Brazilian basins, but rather, restricted only to the southern region of Brazil.…”

“…Several researchers have characterized the reproductive dynamics and their relationship with the breeding season through knowledge of some quantitative indexes such as gonadosomatic index, hepatosomatic index and condition factor (Araújo et al, 1999;Querol et al, 2002;Gomiero & Braga, 2006;Braga et al, 2009;Holzbach et al, 2009;Freitas et al, 2011;Moraes & Braga, 2011). The condition factor is indicative of specimens' health, and it is widely used both in research on aquaculture and fish ecology, in natural and laboratory environments (Camara et al, 2011).…”

Abundância e aspectos reprodutivos de Loricariichthys platymetopon (Siluriformes, Loricariidae) em quatro trechos da represa Capivara, médio rio Paranapanema

“…Recentes estudos sobre sua biologia foram realizados no rio Paraná (DEI TOS et al, 1997) e na bacia do rio Uruguai (QUEROL et al, 2002), e indicam que habita principalmente ambientes lênticos e semi-lóticos, se reproduz nos meses quentes e que os machos carregam os ovos até o momento da eclosão. Na planície de inundação do alto rio Pananá, a comparação de dados obtidos em períodos com diferentes pluviosidades mostrou que o número de exemplares capturados, o tamanho de primeira maturação e o período reprodutivo são maiores quando a cheia é mais pronunciada (DEI TOS et al, 1997).…”