Doras diet

[Silurus]

Penha, IC, L Seabra, E Prata, T Freitas, LFdA Montag, 2024. Unraveling a specialized diet of an Amazonian catfish in a controlled flood pulse area by combining stomach content and stable isotope analyses. Marine and Freshwater Research

Abstract

Context: Hydrological dynamics are crucial in fish ecology.
Objective: To evaluate the effect of the flood pulse on the feeding ecology of Doras higuchii in the reduced flow section of the Belo Monte dam, Xingu River, Brazil.
Methods: Collections were carried out between December/2020 and November/2021. The fish were measured and had their stomachs removed. Muscle tissue was also extracted for stable isotope analysis. Stomach contents were inspected to assess diet, testing the influence of hydrological periods using GLM. In addition, we evaluated the effect of the flood pulse on the δ13C and isotopic ratios of individuals.
Results: A total of 362 specimens of D. higuchii were analyzed, highlighting a diet based mainly on sediment (74.9%) and aquatic insects (24.8%), not varying between periods characterizing the species as a specialist for having detritivorous habit, as well as the extension of the trophic niche. There was variation in food intensity, with higher average food consumption in the flood period. The isotopic composition (δ13C and δ15N) also did not differ between periods. Finally, δ15N did not vary by length classes.
Conclusions: This information helps to understand the interface between environmental and biological factors in an environment impacted by a hydroelectric dam. Implications: Our results may help fill gaps in knowledge about the diet of doradid fishes.