Influence of cage fish farming on the diet of Triportheus nematurus (Kner, 1858) in a neotropical reservoir

• Grant number: 20/13424-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): March 01, 2021
• Effective date (End): February 28, 2022
• Field of knowledge: Biological Sciences - Ecology - Ecosystems Ecology
• Principal Investigator: Igor Paiva Ramos
• Grantee: Vinicius Cesar do Bonfim
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

Cage fish farming in a freshwater environment is one of the main zootechnical activities in Brazil and has great potential to significantly impact aquatic ecosystems. Thus, the present proposal aims to test the hypothesis that there is a difference in dietary aspects of T.nematurus between areas used by aquaculture systems and areas free of this anthropic influence in a Neotropical reservoir. Triportheus nematurus, is a characid species non-native in UpperParaná River that has trophic plasticity, and can thus be influenced by the effects of cage fish-farming, and thus be a good model to assess the influences of this cultivation model. The collection of the specimens was carried out with gill nets, in March and June 2019, in two groups, cage fish farm (TR) and control (CT). The cage fish farm group comprises areas closeto cage fish farming and the group controls areas upstream of cage fish farms, free from the influence of these systems. After collection, all captured specimens were euthanized, frozen,and transported to the laboratory. Subsequently, their stomachs were removed and fixed in 4%formaldehyde and preserved in 70% alcohol for laboratory analysis. Stomach contents will be examined and food items identified to the lowest possible taxonomic level and quantified using the volumetric method. The composition of the diet and its possible differences will be evaluated using the PERMANOVA and SIMPER analyzes, while the average niche breadth using PERMDISP. Also, the trophic guild of the species for each area will be determined. The result of the work can contribute to the composition of bibliography about the species, as well as to the understanding of the environmental impacts of cage fish farms, in addition to contributing to mitigating environmental impacts and helping to promote ichthyofauna conservation projects.