Carbon sources and trophic position of the main species of fishes of Baía River, Paraná River floodplain, Brazil

Abstract

In order to verify the carbon source and trophic position of the main species of fishes, of the Paraná River floodplain, we analysed the proportion of stable carbon (delta 13C) and nitrogen (delta 15N) isotopes in muscle of fishes sampled in the rainy season. We analyzed adult individuals of Loricariichthys platymetopon, Schizodon borellii, Leporinus lacustris, Auchenipterus osteomystax, Iheringichthys labrosus, Leporinus friderici, and Serrasalmus marginatus. These data were compared with the results obtained by the analyzing stomach contents. The primary producers found in the Baía River were the C3 plants (riparian vegetation, macrophytes, periphyton, and phytoplankton) and the C4 plants (macrophytes). The results of the contribution analysis revealed that the carbon used by the species was derived from C3 plants. According to the trophic position estimates (diet and delta 15N), the species primarily consumed Loricariichthys platymetopon, Schizodon borellii, Leporinus lacustris, and Leporinus friderici and, secondarily Auchenipterus osteomystax, Iheringichthys labrosus, and Serrasalmus marginatus. There was no significant difference between the two methods utilized.

Trophic position of bottom-feeding fish in the Upper Paraná River floodplain

“…Various researchers have suggested considering the participation of the microbial loop in the transfer of energy in order to understand the trophic relations in aquatic food chains (Lopes and Benedito-Cecilio, 2002;Manetta et al, 2003;Calheiros, 2003). Bacteria and other microorganisms that are exploited by the consumers can promote the incorporation of food sources that belong to diverse trophic levels.…”

Caloric density of aquatic macrophytes in different environments of the Baía river subsystem, upper Paraná river floodplain, Brazil

“…The Baía river (moderately lotic) presents a varied width and an average depth of 3.2m, with narrow stretches having high embankments and occupied by riparian vegetation or cultivated fields. In the wide stretches, the embankments are low and the vegetation consists of flooded fields (Manetta et al, 2003). Fechada lagoon has an elongated shape, a length of 624.4m and an average depth of 2.5m.…”

“…It does not present a direct connection with the Baía river, which is 100m away. The margin consists of a few trees (1%) and high macrophyte abundance (Manetta et al, 2003). Guaraná lagoon has a rounded shape, a length of 386.5m and an average depth of 2.1m.…”

“…It presents a macrophyte-laden connection with the Baía river that is 70m long and 18m wide. The marginal embankment presents a height of 0.4m and its margins are laden with grasses (95%) and bushes (5%) (Manetta et al, 2003).…”

Use of Food Resources by Detritivorous Fish in Flood-Plains: A Synthesis

“…Several authors have considered the detritus food chain as the main source maintaining the fish biomass in tropical and subtropical aquatic environments (Araujo-Lima et al, 1986, Benedito-Cecilio et al, 2000, Benedito-Cecilio and AraujoLima, 2002, Manetta et al, 2003. In this way, up to 80 % of fish biomass in floodplains is made up by detritivorous species, i.e., dependent on sources of detritus (Agostinho and Zalewski, 1996).…”