Seasonal hydrology and fish assemblage structure in the floodplain of the lower Amazon River

Abstract

Floodplains are nutrient-rich systems subject to periodic flooding (Junk, Bayley, & Sparks,) that play important ecological roles for countless species. Amazonian River floodplains are among the most biodiverse and productive ecosystems in the world (Junk, Soares, & Bayley, 2007). In these ecosystems, the seasonal flood pulse is a major driver of patterns of migration, distribution and abundance of

Ecologia alimentar de Hassar affinis (Actinopterygii: Doradidae) em dois lagos de uma zona úmida de importância internacional no Nordeste do Brasil

“…A diet composed of benthic invertebrates is a source of nutrition for more than half of the fish biomass in South America, and larval forms of insects are the food category most used by the ichthyofauna (Zavala-Camin, 1996). According to Silva et al (2020) studying associations between the structure of the fish assembly and hydrology in the lower Amazon River, species that feed on aquatic insects are mainly associated with periods of flood, this is because, consequently, there is greater abundance and diversity of food resources. Another fact is that rivers and lakes are environments that have sandy substrates and that contribute greatly to the abundance of benthic fauna (Hartz et al, 2000).…”

Length-weight relationship of four species of ornamental fish from the lower Rio Negro basin in the Brazilian Amazon

“…Biological Sciences, v. 44, e60599, 2022 The samplings took place for two days in each month, (September and December 2017, and February, March and April 2018), totaling ten days of sampling. The samplings were carried out in these months, in order to capture fish according to the hydrological cycle (low water -September and December 2017, and high water -February, March and April 2018) (Bittencourt & Amadio, 2007), since the composition of the fish assembly is strongly influenced by the flood pulse (Freitas, Souza, Prado, Yamamoto, & Hurd, 2010;Röpke et al, 2017;Silva, Arantes, Freitas, Petrere Jr., & Ribeiro, 2021;Soares & Yamamoto, 2005). The specimens were captured in the morning (9 -11 am) and in the afternoon (3 -5 pm), close to the shore, where the river bed is comprised mainly of sand and has submerged trunks, with the aid of gillnets (20 m long x 2m high, with 5 mm between knots), and landing nets, which were used specifically for collections close to the trunks.…”

Patterns of Pelagic Fish Diversity in Floodplain Lakes of Whitewater and Blackwater Drainage Systems Within the Central Amazon River Basin of Brazil

“…The present-day physical environment includes an annual hydrologic cycle that alternates between complete inundation of floodplain forests at high water, and formation of floodplain lakes with varying degrees of connection (or isolation) from river channels at low water. This "flood pulse" (Junk et al, 1989), in which water depth can vary 15 m or more depending on specific location along the rivers, is considered to be the dominant feature of the physical environment for fish species in this region Silva et al, 2020). Floodplains occupy 73,500 km 2 (Hess et al, 2015), providing important habitat for Amazonian fish, some of which remain on the floodplain all their lives, dispersing into the flooded forests to feed at high water and then returning to open water of the lakes as the water recedes.…”