Atividade alimentar de espécies de peixe do rio Tibagi, relacionada com o desenvolvimento de gordura e das gônadas

Abstract

ABSTRACT. FEEDING ACTIV ITV AND ITS RELATIONS WITII FAT ANO GONAOAL OEVELO-PMENT OF FlSII SPECIES FROM TIBAG I RIVER.The tish assemblage in a stretch ofTibagi ri ver was studied during the period of one year, throught monthly sampling. lt was observed lhat four fi sh species (Sehizodoll inlel'lIIedius Fernandez-Yepez, 1948) were very tI'equent and they represenl ali lhe main trophic groups. ln order to characterize feeding activity, tàt storage and reproduction the l11eans degree of repletion, fat and maturation, obtained for each species in each month were compared among the four fish species. SIeindac1merina insculpla, a detritivovous species was the one wi th the highest teeding activity while A. lacuslris, a piscivorous fish, showed the lowest feeding ac tivity. For these two species it was clearly observed a sequence of events: higher feeding activity tollowed by higher tàt stOl'age followed by reproduction, that was not observed tor P. maculalus and S. inlermedius. The variations in leeding acti vity and fat stOl'age showed by P. maculalus and S. inlermedius might be related to their diets. KEY WORDS. Fish, feeding activity, gonadal development, Tibagi ri ver, Paraná Nos rios neotropicais os estudos rel acionando atividade alimentar, desenvolvimento de gordura e reprodução dos peixes, enfocam, de uma maneira geral, como dependentes do ciclo hidrológico, quando ocorrem períodos bem marcados de cheia e seca. Assim na época das chuvas é quando ocorre a maior atividade alimentar e também o arm azenamento de gordura para, em seguida ocorrer a desova. Nesta situação, o alimento dos peixes é principalmente de origem alóctone, proveniente das matas e que se torna acessível e abundante na época das chuvas. Em estudos dos peixes de rios da reg ião amazônica esses aspectos são mencionados por GOULDING (1980), JUNK (1985) e LOWE-McCONNELL (1987 e na bacia do rio Orinoco por MACH ADO-ALLISSON (1992).No entanto, além dos fatores hidrológicos, vários fatores biológicos podem estar relacionados. GOULDlNG (1980) menciona que as diferentes dietas, bem como a natureza e origem do alimento, e o porte da espécie devem ser considerados. JUNK (1985) associa o desenvolvimento de gordura e sua sazonalidade à migração e

Reproductive biology and feeding of Curimatella lepidura (Eigenmann & Eigenmann) (Pisces, Curimatidae) in Juramento reservoir, Minas Gerais, Brazil

“…In the present study, GSI peak associated to decreasing of HSI at advanced maturation suggest liver participation in the vitellogenin synthesis and mobilisation of energetic reserves for reproduction since the feeding activity is reduced or interrupted during reproduction in accordance with other authors (HTUN-HAN 1978, AGOSTINHO et al 1990, BAZZOLI & GODINHO 1991, TAVARES & GODINHO 1994, BENNEMANN et al 1996. Higher CFI in resting period decreasing during the advanced maturation indicated energetic consume for concluding the reproductive activity, which was compensated by a greater feeding activity at resting similar to other Characiformes (NOGUEIRA et al 1997, BARRETO et al 1998, BRITO et al 1999, HOJO et al 2004.…”

Feeding of Oligosarcus hepsetus (Cuvier, 1829) (Characiformes) in the Serra do Mar State Park - Santa Virgínia Unit, São Paulo, Brazil

“…A high incidence of empty stomachs of many carnivorousichthyophagous species was also found by Goulding (1980), Cruz et al (1990) and Bennemann et al (1996). Although Oligosarcus hepsetus showed this characteristic, a large number of individuals had full stomachs in spring.…”

“…Thus, Oligosarcus hepsetus apparently feeds more frequently in the spring and summer, storing a large fat reserve that will be used in autumn and winter as a source of energy for survival and gonad development. This behavior was observed by Bennemann et al (1996) for Acestrorhyncus lacustris, which was actively reproducing in the area studied (Tibagi River, Paraná state), and for which the sequence of events of increased feeding activity, fat storage, and then breeding could be established.…”

Biological aspects of Schizodon nasutus Kner, 1858 (Characiformes, Anostomidae) in the low Sorocaba river basin, São Paulo state, Brazil

“…Therefore, it is important to consider both hydrological and biological factors, which coordinate such relations with the studied habitat (Bennemann et al, 1996). Vazzoler (1996) mentions that the condition factor is an important indicator of the level of well-being in fish, and its value indicates recent nutritional conditions and/or reservoir expenses in cyclic activities, making it possible to comprehend relations with environmental conditions and behavioural aspects of a considered species.…”