Diet of Psalidodon aff. fasciatus (Cuvier, 1819) (Teleostei: Characidae) in a neotropical river before reservoir formation

Abstract

The main objective of this study was to identify spatial and seasonal variations on the diet of Psalidodon aff. fasciatus from the Tibagi River (South Brazil) before the construction of the Tibagi Montante hydropower plant. Fish were collected quarterly between October 2017 and July 2019. 536 stomachs containing feeding items and identified to the lowest taxonomic level as possible have been analyzed. Results showed that plants, Hymenoptera, and insect parts in general were the most consumed items. The analysis of feeding strategy showed a diet based on rare items but with individuals varying among specialist, generalist, and opportunistic trends depending on the season. The non-metric multidimensional scaling (NMDS) revealed diet overlap in both spatial and seasonal terms, which was confirmed by the permutational analysis of variance (PERMANOVA). The indicator value analysis (IndVal) identified 15 items as the most important components of this species’ diet such as superior plants, Hymenoptera and insect parts. Therefore, before the formation of the reservoir, P. aff. fasiatus could be characterized as predominantly herbivore with a strong trend for insectivory. Across seasons, this species had a specialized diet all year, although with more specialized preferences in the spring when the consumption of plants was increased.