Trophic ecology and isotopic and physiological biomarkers of two species of fish belonging to different trophic guilds (omnivorous and carnivorous) associated with cage fish farms

• Grant number: 22/00839-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): April 30, 2022
• Effective date (End): September 29, 2022
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Igor Paiva Ramos
• Grantee: Bruna Caroline Kotz Kliemann
• Supervisor: Juan Antonio Balbuena Diaz-Pines
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil
• Research place: Universitat de València, Spain
• Associated to the scholarship: 18/01117-2 - Trophic ecology and physiological biomarkers of two species of fish belonging to different trophic guilds (omnivorous and carnivorous) associated to cage fish farms, BP.DR

Abstract

Evidence indicates that cage fish farms in freshwater promote variations in environmental conditions, directly interfering with the foraging behavior of wild fish. However, the biological effects of the consumption of fish crop residues on the wild ichthyofauna of Brazilian reservoirs are little known. This proposal aims to evaluate the influence of cage Fish farms on the trophic ecology (consumption and assimilation) and physiological aspects of two wild fish species in the Ilha Solteira Reservoir, SP. Surveys were carried out in April and July 2019, August 2021, and March 2022 covering the wet (March and April) and dry (July and August) periods in five areas (two control areas and three cage farm areas). The stomach contents collected from Geophagus sveni and Plagioscion squamosissimus individuals were analyzed. Five individuals per species and area were selected for isotopic analysis and ten individuals for physiological assays. Studies integrating physiology and diet (stomach content and stable isotopes) can help to clarify the influences of cage fish farming on wild biota. In addition, they can contribute to biomonitoring studies of aquaculture activity, this approach being unprecedented in the context of physiological studies of freshwater fish in Brazil. (AU)