Population structure, condition and diet of Oligosarcus paranensis (Menezes & Gery, 1983) (Osteichthyes: Characidae) at two reservoirs in South Brazil

Abstract

This study investigated the population parameters, condition and diet of Oligosarcus paranensis at Fiú and Mourão Reservoirs, located in Paraná State, Brazil. The fishes were collected quarterly between 1996/1997 and 1998/1999 using gillnets. Food items were quantified by volumetric method. The specimens at Fiú showed comparatively smaller length and worse condition. Sex ratio was statistically equal to 1:1 at Mourão, whereas there was a significant predominance of males at Fiú. Sex ratio also varied among size classes. Allometric growth prevailed among the studied groups. The diet consisted mainly of fishes and was complemented with invertebrates and plant matter in both reservoirs. There was a change in the feeding pattern as the standard length increased. Fishes changed from invertivores to piscivores, except for males in Mourão, for which a reverse trend occurred.

Length-weight relationships for 22 neotropical freshwater fishes from a subtropical river basin

“…In relation to the characids, b values of Astyanax fasciatus and Bryconamericus iheringii were larger than those available (2.880–3.140) (Froese and Pauly, ), because our length range comprised larger fishes. Estimates presented here are similar to those observed in other areas for A. altiparanae (Gubiani et al., ; Oliva‐Paterna et al., ; Orsi and Britton, ), A. paranae (Abelha and Goulart, ; Gubiani et al., ) and Oligosarcus paranensis (Gubiani et al., ; Oliva‐Paterna et al., ; Abelha et al., ), showing conservative patterns for these species. The same applies to Apareiodon ibitiensis (Barbieri et al., ), A. piracicabae (Gubiani et al., ; Orsi and Britton, ), Hypostomus albopunctatus (Antoniutti et al., ), H. regani (Gubiani et al., ; Nuñer and Zaniboni‐Filho, ) , H. strigaticeps (Lima‐Junior et al., ) and Prochilodus lineatus (Benedito‐Cecílio et al., ; Gubiani et al., ; Nuñer and Zaniboni‐Filho, ; Oliva‐Paterna et al., ).…”

Spatial and temporal variations in fish assemblage: testing the zonation concept in small reservoirs

“…On the other hand, O. paranensis is also documented as one of the fish species that succeeds in the occupation of reservoirs (Agostinho et al, 1999;Smith and Petrere Júnior, 2008), probably because of its fast growth, which means a rapid development (Abelha et al, 2012). In addition, the diet of this species is based mostly on invertebrates for juveniles and fish for adults, using natural habitat structures for predation (Casatti et al, 2001).…”

Environmental assessment in tropical streams by using abundance-biomass curves and W index in fish assemblages

“…The species more correlated with the urban (impacted) streams were those suited to live in siltation (a condition derived from low canopy cover and representative of low mesohabitat diversity), such as H. ancistroides (Casatti et al, 2005), I. schubarti (Severo-Neto et al, 2015), andH. strigaticeps (Jepep et al, 2007), with high feeding plasticity (impacted streams are frequently recorded as food resource restricted), like R. quelen (Gomiero et al, 2007), G. inaequilabiatus (Hahn et al, 2004), G. brasiliensis (Bastos et al, 2011), Bryconamericus iheringii (Oliveira & Bennemann, 2005;Oricolli & Bennemann, 2006), A. lacustris (Bennemann et al, 2005, under A. altiparanae), and O. paranensis (Abelha et al, 2012), adapted to feed on organic detritus (a typical food resource in impacted streams), as H. ancistroides and H. strigaticeps (Pagotto et al, 2011), and with high reproductive plasticity, as S. marmoratus (Favorito et al, 2005). All these species are adapted to use scarce alimentary, shelter, and reproductive resources, as appears to be the case here.…”