Detritivory in two Amazonian fish species

Abstract

In floodplain lakes of Central Amazon, the siluriform Liposarcus pardalis and the characiform Prochilodus nigricans consumed detritus with different compositions. Most of the diet of L. pardalis and P. nigricans was made of amorphous organic matter. The food ingested by L. pardalis had relatively higher organic matter (OM) (35-55%) and crude protein (10-19%) than that found in P. nigricans stomachs (10-20% and 2-5%, respectively). Both fish ingested higher quantities of OM and crude protein during the high-water season. The differences between the two species seem to be related to their ability to select different detrital components. Striking differences were also found in the digestibility rate of OM and protein between the two species. Prochilodus nigricans assimilated only 2·3% of its intake compared with 24% in L. pardalis. 1998 The Fisheries Society of the British Isles

Astyanax paranae Eigenmann, 1914 (Characiformes: Characidae) in the Alagados Reservoir, Paraná, Brazil: diet composition and variation

“…This is a food originated from different sources of carbon (cellulose, lignin, chitin and other) and presents particles of variable size, colonized in different degrees by fungi and bacteria, its main source of protein (Bowen, 1979;Yossa & Araujo-Lima, 1998;Crossman et al, 2001;Moore et al, 2004). In this context, it is possible to cogitate the occurrence in Alagados Reservoir of detritus qualitatively improved.…”

“…This fact could be justified by the low biomass of periphytics algae in Alagados Reservoir (Rodrigues et al, 2005) and the intrinsic link of benthic algae to non live detritus/sediment extract (Bowen, 1983;Gerking, 1994;Yossa & Araujo-Lima, 1998;Crossman et al, 2001;Moore et al, 2004). Occurrences of algae in the diet of A. paranae were also reported for stream populations (Ferreira, 2004), however, the absence or inexpressive consumption of detritus/ sediment indicated, in these cases, the intentional ingestion of this food.…”

Reproduction, feeding and migration patterns of Prochilodus nigricans (Characiformes: Prochilodontidae) in northeastern Ecuador

“…Diet, energy sources and food assimilation of black prochilodus have been widely studied through direct analyses of the stomach contents, fat storage and analyses of stable carbon isotopes by several authors (Goulding, 1981;Junk, 1985;Araujo-Lima et al, Yossa, Araujo-Lima, 1998Goulding, 1981Junk, 1985;). Although visual assessment of stomach fullness of black prochilodus in the Aguarico River was qualitative, it showed a decrease in feeding activity during migrations (Fig.…”

Quality and digestibility of food ingested by various trophic fish groups in the Upper Paraná River floodplain

“…Another strategy that allows such efficiency is the ability to ingest large quantities of food in relation to body weight (Yossa & Araújo-Lima 1998). The fact that there were discrepancies in energy, protein, and ADC contents for P. lineatus may be related to the quantity of ingested food because the diet of P. lineatus is mainly composed of detritus and sediment (Table 1) (Hahn et al 2002).…”

“…Nose (1966) reports that, in general, protein is adequately digested by most fish species, except for a few plant protein sources or in the presence of high levels of carbohydrates in the diet. Few studies have been developed in Brazil with this focus in natural environments (Yossa & Araújo-Lima 1998, Silva et al 2000. Some research has shown that the effective assimilation of food by fish depends also on the hydrological regime, environmental condition, water temperature, food intake, and nutrient quantity and quality, as well as the physical state of food items (Silva et al 2000).…”