Feeding ecology of Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) in a riparian flooded forest of Eastern Amazonia, Brazil

Abstract

Feeding habits of the midnight catfish Auchenipterichthys longimanus collected in rivers of the Caxiuanã National Forest (Eastern Amazonia, Brazil) were investigated through the different hydrological periods (dry, filing, flood and drawdown). A total of 589 specimens were collected throughout seven samplings between July 2008 and July 2009, of which 74 were young males, 177 adult males, 89 young females and 249 adult females. The diet composition (Alimentary index - Ai%) was analyzed by a non-metric multidimensional scaling (nMDS) and by the analysis of similarity (ANOSIM), which included 37 items grouped into nine categories (Aquatic insects, Other aquatic invertebrates, Arthropods fragment, Fish, Plant fragment, Seeds, Terrestrial insects, Other terrestrial invertebrates, and Terrestrial vertebrates). We also calculated the niche breadth (Levins index) and the repletion index (RI%). Differences in the diet composition between hydrological seasons were registered, primarily on diet composition between dry and flood season, but changes related with sex and maturity were not observed. The midnight catfish showed more specialists feeder habit in the flood period (March 2009) and more generalist habits in the dry season (November 2008). The amount of food eaten by A. longimanus based on repletion index (RI%), did not differ significantly from sex and maturity. However, we evidenced differences in RI% when comparing the studied months. These results provide important biological information about the trophic ecology of auchenipterids fish. In view of the higher occurrence of allochthonous items, this research also underpins the importance of riparian forests as critical environments in the maintenance and conservation of wild populations of fish in the Amazon basin.

Feeding ecology of Serrasalmus gouldingi (Characiformes: Serrasalmidae) in the lower Anapu River region, Eastern Amazon, Brazil

“…During this season, a large amount of fruits produced by floodplain trees fall into the water and are ingested or dispersed by many different fish species (Claro-Jr et al 2004;Ferreira and Parolin 2007;Freitas et al 2011). Therefore, our results are consistent with the results of other studies carried out in Amazonia involving Serrasalmus, in the upper Madeira River (Goulding 1980) and in the lower Negro River (Leão et al 1991), where a higher amount of fruits and seeds was consumed during flood season.…”

“…This was also demonstrated by studies on many tropical fishes living in habitats influenced by flood pulses (Winemiller 2005;Freitas et al 2011;Correa and Winemiller 2014). During high water season, the flooding of adjacent areas not only contributes to nutrients input into the aquatic ecosystem (such as terrestrial invertebrates, fruits and seeds), but also allows for the exploitation of available resources in these areas (Junk et al 1989;Winemiller 2005).…”

“…Nonetheless, it is possible to observe four distinct hydrological periods -receding water (June-August), drought (September-November), rising water (December-February), and flood (March-May). These hydrologic periods were previously defined by Freitas et al (2011) that investigated the effect of fluviometric variation in the feeding ecology of catfish Auchenipterichthys longimanus in the same region of the present study. Fink and MachadoAllison 1992 (Serrasalmidae) were collected bimonthly from July, 2010 to May, 2011.…”

Variação temporal e espacial na dieta de Trachelyopterus galeatus (Siluriformes, Auchenipteridae) em dois reservatórios no semiárido Neotropical

“…Segundo Ferraris Jr. (2003) os auquenipterídeos habitam nichos muito parecidos, são espécies noturnas, escondendo-se durante o dia em fendas de rocha e ramos e árvores submersas, o que provavelmente envolveu várias adaptações semelhantes em morfologia e comportamento (Freitas et al, 2017), sendo considerados generalizadas como carnívoras, predominando principalmente insetos, bem como o plâncton e peixes (Ferraris Jr., 2003). Esta aspecto explica a semelhança do hábito alimentar das espécies pertencente ao gênero Auchenipteridae, como insetívoros para Auchenipterus nuchalis (Mérona et al, 2008) insetívoros/ frugívoros para Auchenipterichthys longimanus (Freitas et al, 2011) e Tatia intermedia (Ramírez et al, 2015) e Trachelyopterus galeatus (Ximenes et al, 2011) e insetívoros para Auchenipterichthys longimanus, Auchenipterus nuchalis, Trachelyopterus galeatus e Tatia intermedia (Freitas et al, 2017).…”

Distribution, feeding and ecomorphology of four species of Auchenipteridae (Teleostei: Siluriformes) in Eastern Amazonia, Brazil

“…Regarding the Family Auchenipteridae (Siluriformes), available data on ecology and biology addresses only a few species (Moresco & Bemvenuti, 2005;Santos, 2005;Freitas et al 2011;Maia et al, 2013;Santos et al, 2013). The Auchenipteridae species are endemic to the Neotropics and belong to two subfamilies: Centromochlinae and Auchenipterinae (Birindelli, 2014).…”