Trophic ecology of Myloplus tiete (Characiformes, Serrasalmidae), a native and endangered species: integrated approach between stomach contents and stable isotopes

• Grant number: 23/01779-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: May 01, 2023
• End date: February 28, 2025
• Field of knowledge: Biological Sciences - Ecology - Ecosystems Ecology
• Principal Investigator: Igor Paiva Ramos
• Grantee: Natália Luiza da Silva
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil
• Associated scholarship(s): 24/00127-5 - Trophic ecology of Myloplus tiete (Characiformes, Serrasalmidae), a native and endangered species: integrated approach between stomach content and stable isotopes, BE.EP.MS

Abstract

Covering in its territory a dense and extensive network of aquatic environments, Brazil stands out worldwide for its richness and diversity of ichthyofauna. However, a significant number of these species are threatened with extinction, such as Myloplus tiete, popularly known as "pacu rosa", "pacu prata" or "pacu peva". Endemic to Brazil, it is currently occurs in a few locations on the Paraná River, being classified in the "Endangered" threat category, with little information about its biological aspects. Thus, the present project aims to evaluate the trophic ecology of M. tiete at the population and individual level using integrated approaches between analyzes of the stomach content and stable isotopes, in order to deepen the knowledge on biology and feeding behavior, providing information that may contribute to the conservation of the species. Eighty specimens of M. tiete will be collected from the reservoir of the Hydroelectric Power Plant "Engenheiro Souza Dias" (Jupiá), located on the Paraná River, in the municipality of Itapura/SP. Stomach content analyzes will be used to characterize the composition of the population's diet and to evaluate dietary aspects at an individual level, seeking to verify whether individuals behave in different ways. On the other hand, using the analysis of stable isotopes of 13C and 15N, it will be possible to verify the assimilation of food resources and confirm whether the food items observed in the stomach contents are effectively assimilated and used nutritionally. Furthermore, if it is possible to compare the sexes, it will be investigated whether males and females have a diet and assimilate food resources similarly, since they have different energy requirements related to reproduction. It is expected that the results of this proposal will contribute to the knowledge about the feeding biology of M. tiete, as well as in the elucidation of some aspects of population dynamics, since through the evaluation of the individual diet it is possible to identify strategies for greater stability and population survival. Additionally, verify whether the analyzed population is composed of specialist and/or generalist individuals, may help in understanding the survival mechanisms of the species. It is also expected that the results can contribute to future studies that aim to create strategies for the conservation of the species.