Fish Fauna in Oxbow Lakes of the Middle Purus River in the Neotropical Region of the Amazon Rainforest

Abstract

The effect of the flood pulse directs productivity and interactions of biota in abandoned oxbow lakes, as these habitats provide refuge from predators and serve as nurseries and feeding grounds for many fish species. The present study was conducted in twelve oxbow lakes with varying degrees of connectivity, located in the floodplain of the Middle Purus River in Brazil. 8.647 individuals were collected among 157 species. Lakes with high hydrological connectivity were shown to have the largest richness of species (131 species), while lakes with medium connectivity had slightly smaller richness (123 species), and lakes with low connectivity had even less (113 species). The results show high diversity in lakes that are attributed different connectivity, thereby indicating the importance of studies focused on oxbow lakes that contribute with relevant information on the composition of fish species in the Middle Purus River.

The consumption of fish by the riverine population of the lower Solimões River, Amazonas, Brazil

“…In South America, Characiformes dominate the ichthyofauna, and species of this order make up a good part of the fish assemblages in floodplain lakes (Siqueira-Souza and Freitas, 2004;Granado-Lorencio et al, 2012;Borie et al, 2019;Dagosta and Pinna, 2019;Virgilio et al, 2020). The preference of riverine communities for consumption of species of this order has already been observed in other studies (Garcez et al, 2009;Silva et al, 2017;Begossi et al, 2019).…”

Free and underfit-scavenger river dynamics dominate the large Amazonian Pacaya-Samiria wetland structure

“…In particular, the Prochilodus nigricans is an important fishery species in the Andean-Amazon region, a detritus feeder that lives in floodplains and channels during the low-water season to later migrate to tributaries (McClain and Naiman, 2008). The Pseudorinelepis genibarbis is an omnivorous armored catfish that live in low-oxygen waters that can be found in floating meadows and oxbow lakes (Virgilio et al, 2020). As shown in Figure 9, fishing zones of Prochilodus nigricans include paleochannels within the Marañon and Ucayali floodplains; these areas are composed of palm swamps (Figure 10B) that contain detritus rich in amino acids with a greater nutritional value (Bowen, 1983).…”

“…As a result of the constant development of the floodplains caused by seasonal alluvial flows, previous studies suggest that the diversity of the vegetation from different ages generated the high biological diversity in the Amazon rainforest (Salo et al, 1986). Therefore, dynamic flow regimes establish critical interactions between the main channel and adjacent floodplain habitats, such as "tipishcas" or oxbow lakes, thereby providing fish and other aquatic species access to shelter, food, and spawning grounds (Junk et al, 1989;Couto et al, 2017;Virgilio et al, 2020). According to Castello et al (2013), this dynamic interaction explains the high ecological value of the Amazonian ecosystems but also makes them more sensitive to anthropogenic pressures.…”