Effect of flood pulses on the trophic ecology of four piscivorous fishes from the eastern Amazon

Abstract

This study investigated the effect of hydrological periods on the feeding activity and trophic interactions of four piscivorous fishes from the middle Xingu River, Brazil: pike-characid Boulengerella cuvieri, dogtooth characin Hydrolycus armatus, dogtooth characin Hydrolycus tatauaia and South American silver croaker Plagioscion squamosissimus. Repletion Index (I %), Alimentary Index (I %) and food web properties were calculated for each species. A total of 825 specimens were collected. The I showed changes in feeding intensity of B. cuvieri, H. armatus and H. tatauaia among hydrological periods. Flood pulse showed no influence on composition and importance of food items consumed. Trophic connections showed that connectivity ranged from 0.025 to 0.038. The highest number of trophic connections (75) occurred in the high-water period, when 51 food items were recorded and the lowest number of trophic connections (43) occurred in receding water, with 31 food items. In all food webs, over 45% of food items were consumed by only one species (ultra-peripheral items), which is common in piscivorous fishes.

Population and reproductive parameters of the red-tailed catfish, Phractocephalus hemioliopterus (Pimelodidae: Siluriformes), from the Xingu River, Brazil

“…1), the climate is tropical hot and humid, Am type in the Köppen-Geiger classification (Peel et al, 2007). The predominant vegetation is typical lowland Amazon rainforest (Barbosa et al, 2018). The annual fluviometric variation recorded on the river can be divided into four distinct hydrological periods: the dry (September-November), filling (December-February), flood (March-May), and receding (June-August) (see Barbosa et al, 2015;.…”

“…In the context of these effects of river impoundment, studies of the reproductive biology of fishes constitute an essential tool for the better understanding of population dynamics related to the seasonal variation in the environmental factors observed in aquatic ecosystems (Freitas et al, 2015;Barbosa et al, 2018). In the Amazon basin, this seasonality is derived naturally from the hydrological oscillations of the flood pulse (Junk et al, 1989), which plays a significant role in the maturation of fish gonads, the spawning season, and larval development (Goulding, 1980;Zeug, Winemiller, 2008).…”

Mercury concentrations in fish and human health assessment in preflood phase of a hydro dam in Teles Pires River, Southern Brazilian Amazon

“…However, a more detailed study in Xingu River showed that for B. cuvieri, the most important food items are Geophagus sp. and Leporinus sp, and for H. armatus, they are Cichla melaniae (Barbosa et al, 2018). Piranhas are fish with a tooth structure adapted to pull pieces (scales, fins, muscle) from their prey (Piorski et al, 2005), allowing them to feed on larger fish.…”

Avaliação Do Binômio Saber Popular Versus Saber Científico De Plantas Medicinais No Conteúdo Programático Do 3º Ano Do Ensino Médio

“…A contaminação mercurial vem sendo discutida no mundo (Díezet al, 2011;Cristol et al, 2012;Carravieri et al, 2013;Ceccatto et al, 2015;Eagles-Smith et al, 2016;Ferreira et al, 2017;Barbosa et al, 2018;Matos et al, 2018;Lino et al, 2018;Pestana et al, 2019). No Brasil, e em especial na Amazônia e o Pantanal de Mato Grosso, estudos recentes demonstram ocorrência de fontes pontuais e difusas de liberação do metal devido às concentrações encontradas na biota (Ceccatto et al, 2015;Ferreira et al 2017;Santos-Filho et al, 2017;Cebalho et al, 2017), e…”