Reproductive biology of Steindachnerina insculpta (Fernandez-Yépez) (Teleostei, Curimatidae) in Furnas reservoir, Minas Gerais, Brazil

Abstract

The 'saguiru' Steindachnerina insculpta, a small teleost detritivorous fish species in Furnas reservoir, upper rio Paraná basin, Minas Gerais, Brazil, has a prolonged period of reproductive activity that extends from September to March, with fractionated spawning. During gonadal maturation, the females showed a low hepatosomatic index, suggesting that hepatic substances are possibly transferred from liver to ovaries. During the reproductive period, this fish had lower stomach repletion and coelomic fat indexes, indicating that the species eat less and consume more fat reserves. The weight of the ovaries influenced positively the condition factor (K1), since the lowest K2 values (without the gonads weight), were obtained during maturation, confirming the influence of the weight of the ovaries upon the physiological condition of the females.

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

“…This reinforces the idea that there is an accumulation of reserves for reproductive activity. Similar results were found for Loricariichthys platymetopon and Rhinelepis aspera (Agostinho et al, 1990;Querol et al, 2002), and also for Characiformes, such as Leporinus copelandii Steindachner, 1875 (Costa et al, 2005), Steindachnerina insculpta (Fernández & Yépez, 1948) (Ribeiro et al, 2007), Astyanax henseli de Melo & Buckup, 2006(Dala-Corte & Azevedo, 2010, among others. According to Svedäng & Wickström (1997), in the case of females, the decrease in HSI during the maturation period is mainly due to the depletion of liver reserves as a result of depletion of glycogen and lipids in hepatocytes, where the synthesis of vitellogenin (Mommsen & Korsgaard, 2008) and transfer to oocytes take place.…”

“…Variation in this index over the year can be used as additional data in the study of seasonal cycles of feeding and reproduction (Braga, 1986;Lima-Junior et al, 2002.) The condition factor and gonadosomatic indexes, which reflect the development of ovaries or testicles as percentages of total weight, can indicate the breeding season of a given species, and they are being frequently used for this purpose by many researchers in several Brazilian basins (Vazzoler, 1996;Costa et al, 2005;Ribeiro et al, 2007;Holzbach et al, 2009). Both males and females showed greater differences between K and K´ from August/September through February/March.…”

Biologia reprodutiva de Astyanax henseli (Teleostei, Characidae) do curso superior do Rio dos Sinos, RS, Brasil

“…Alguns autores sugerem que os peixes ingerem uma maior quantidade de alimento e aumentam as reservas hepáticas no período que antecede a reprodução. Durante o período reprodutivo, os indivíduos alocariam um menor esforço na obtenção de alimento e consumiriam as reservas estocadas no fígado, ocasionando quedas no IR e no IHS (NIKOLSKY, 1963;BARBIERI et al, 1996BARBIERI et al, , 2001RIBEIRO et al, 2007;BALLESTEROS et al, 2009). No presente estudo, não houve correlação das médias do IGS com as do IR e do IHS, para ambos os sexos.…”

How does diet influence the reproductive seasonality of tropical freshwater fish?: A case study of a characin in a tropical mountain river

“…We used Pearson correlations to examine the degree of association between total prey volume, volume of the most important prey types (Diptera larvae and seeds), factors associated with the reproduction (gonad and fat weight, obtained from TorresMejia & Ramírez-Pinilla, 2008), and rainfall. Since fat reserves influence gonadal maturation (Blanco-Parra & BejaranoRodríguez, 2006;Ribeiro et al, 2007), we tested whether the volume of the most abundant prey (Diptera and seeds) influence fat weight. We explored the possibility that there was a lag in the correlation among total prey volume, gonad weight, and fat weight in month x with each relevant explanatory variable at the same month (x), one months before (x -1), two months before (x -2), one month later (x + 1), and two months later (x + 2).…”