Data for: Diet of large Catfishes from Madeira River
Description
This dataset was used in Röpke et al. 2025 “Diet seasonality and resource partitioning by large catfishes in the Madeira River, Brazil. Published at Acta Amazonica to investigate two questions: (1) Do the diets of Brachyplatystoma species, as habitat specialists with large home ranges, exhibit seasonal variation?; and (2) How do habitat use and congeneric traits relate to the trophic segregation of large catfish species, enabling their co-occurrence in the Madeira River? The diet was described for eight species, of which diet seasonality was tested for four, while diet dissimilarity and overlap were estimated for seven regarding only the low-water season. The large pimelodids feed upon many fish families. Most Brachyplatystoma species did not exhibit seasonal shifts in prey consumption. Diet overlap was higher among congeneric and channel-restricted species, particularly Brachyplatystoma platynemum, B. rousseauxii, and B. vaillantii. Despite the diet overlap, some degree of trophic niche partitioning was observed, even among channel-restricted Brachyplatystoma species, mainly when comparing B. filamentosum to the other congeneric species.
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The file include dietary information for the eight most abundant large catfish species in the surveyed fish markets of the study region: Brachyplatystoma platynemum (Boulenger 1898), B. filamentosum (Lichtenstein 1919), B. rousseauxii (Castelnau 1855), B. vaillantii (Valenciennes 1840), Pinirampus pirinampu (Spix and Agassiz 1829), Pseudoplatystoma punctifer (Castelnau1855), P. tigrinum (Valenciennes 1840), and Zungaro zungaro (Humboldt 1821). Data collection was carried out along a transect spanning approximately 600 km over the Mamoré - Madeira River basin, including three urban fish markets and 12 riverine communities with fisheries landings located on the banks of the river. Data collection occurred between April 2009 and September 2011, covering both the low-water (usually from May to October) and high-water periods (usually from November to April), before reservoir flooding by the dams, which started in September 2011. Data collection was conducted as part of the Fisheries Monitoring and the Fish Ecology and Biology Monitoring programs, associated with the environmental studies of the Santo Antonio and Jirau Hydroelectric power plants (Doria et al. 2010). Stomachs were obtained weekly from fishes captured by commercial fisheries and landed at the 15 fishing sites across the study area, preserved and sent monthly to the Laboratory of Ichthyology and Fisheries at the Federal University of Rondônia (LIP/UNIR) in Porto Velho, Rondônia, Brazil. At each site, a local trained collector or a technician from LIP/UNIR recorded the standard length (mm), total weight (g), fishing date and locality during fish landings. Stomachs were examined and prey items (columns 11-95) were identified to the most detailed taxonomic level possible by taxonomy experts, using specialized literature and reference collections at UNIR. For each stomach containing food items, the relative volume of each food item was visually estimated relative to the total stomach content, considering the total volume of the items as 100%. Stomach fullness was also visually estimated on a scale from 1 to 3, where 1 indicated less than 25% fullness, 2 indicated 25-75% fullness, and 3 indicated more than 75% fullness. Detailed description can be found in Röpke et al. 2025.