Ontogenetic change in the diet of Semaprochilodus insignis (Characiformes: Prochilodontidae) during migration between two limnologically distinct environments in the Amazon Basin

Abstract

Semaprochilodus insignis is an Amazonian migratory fish species, moving in large shoals between white- and black-water rivers. It has long been classified as a detritivorous fish. However, it is possible that the trophic plasticity of S. insignis could be higher than previously assumed. The objective of this study was to investigate the relative contributions of autotrophic energy sources to the diet of S. insignis in the Negro and Solimões rivers and to determine if the species undergoes an ontogenetic change in the diet. We found variations between the δ13C and δ15N values of S. insignis between the rivers. In the Negro River, periphyton (84%) was the principal energy source for adults, while juveniles in the Solimões River foraged predominantly on terrestrial plants/C3 macrophytes (50%) and phytoplankton (42%). These variations in isotopic signatures are likely associated with migratory movements of S. insignis at different life stages and hydrological periods. Instead of the previously assumed dietary classification, we suggest that S. insignis varies its diet ontogenetically, with adults acting as illiophagous in black-water while the young are detritivorous in white-water rivers. The results show that this species creates complex links between food chains, thus emphasizing the importance of conserving flooded areas.

Nutrients Affecting the Characteristics of Food-Web Structure in Aquatic Ecosystem of Pearl River

“…2017 and Jan. 2017 might be affected by contamination by calcium in the rocks they were growing on. The δ 13 C values of periphyton in this study were similar to those reported by previous studies [27]. Previous studies demonstrate the importance of periphyton for shrimp growth, including postlarvae.…”

“…In river ecosystems, periphyton is the main carbon source for consumers, [26], there were studies showing that the δ 13 C values of periphyton are relatively low, ranging from −37.34‰ to −19.19‰ [27][28][29], and have noted that these values can be affected by other primary producers in the water along the rock belt [30][31][32]. The δ 13 C value of periphyton is significantly related to their growth environment.…”

Stable mean trophic level and decreasing fish size in Central Amazonian fishery landings

“…Thus, in addition to ecological importance, omnivores are historically important for commercial fisheries in the region, with species such as tambaqui and matrinxã being among the largest known landings (Gonçalves et al., 2021; Goulding et al., 2019). Strategies for exploring food resources available in different periods of the hydrological cycle could be through migratory behavior and ontogenetic changes, thus making it difficult to define the feeding pattern of Amazonian fish species (Soares et al., 2021).…”

Isotopic niche alteration of a predator fish in a dammed Amazonian black water river

“…Based on this, the concept of the isotopic niche was proposed, in which the axes of the multidimensional space are isotopic values that record bionomic and scenopoetic ecological information (Newsome et al ., 2007). Several authors have demonstrated that the isotopic niche is an important tool for exploring resource partitioning (Alves et al ., 2020), ontogenetic dietary shifts (Soares et al ., 2021) and niche overlap (Pennock et al ., 2021). This tool is especially useful for predator species, where the isotopic niche can provide a quantitative estimate of the energetic contribution and trophic level of prey species.…”