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Context: Hydrological dynamics are crucial in fish ecology. Aims: 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 conducted 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 by using GLM. In addition, we evaluated the effect of the flood pulse on the δ13C and isotopic ratios of individuals Results: In total, 362 specimens of D. higuchii were analysed, highlighting a diet mainly on the basis of sediment (74.9%) and aquatic insects (24.8%), not varying between periods characterising 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 class. Conclusions: This information helps understand the interface between environmental and biological factors in an environment affected by a hydroelectric dam. Implications: Our results may help fill gaps in knowledge about the diet of doradid fishes. Exploring what fish eat is important to understand how changes in the environment can affect their lives. In this study, we looked into the diet of an Amazonian catfish in a river affected by the construction of a dam. We found that the catfish mostly fed on sediment and aquatic insects, and these feeding habits were not strongly influenced by changes in the local water levels. [ABSTRACT FROM AUTHOR]

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Observations of skeletal malformations in fish in the wild are poorly documented and need to be investigated. Here we report the occurrence of body shortening in specimens of Plagioscion squamosissimus collected in the Volta Grande do Xingu, middle Xingu River region (Pará, Brazil), during a 12-month monitoring program (2021–2022). We observed morphological anomalies in nine individuals, of which two underwent radiographic analysis, recording the fusion and compression of vertebrae in different portions of the spine. The average percentage decrease in body length resulting from the deformity was 23.8%. This is the first record of malformation in this species. [ABSTRACT FROM AUTHOR]

Copyright of Neotropical Biology & Conservation is the property of Pensoft Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biota Neotropica is the property of Biota Neotropica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)