Assessment of environmental influences of cage fish farming systems on the functional diversity of wild ichthyofauna in a Neotropical reservoir

• Grant number: 22/00054-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2022
• End date: November 30, 2022
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Inland Water Fishery Resources
• Principal Investigator: Igor Paiva Ramos
• Grantee: Julia Kaori Kuriyama Ramos
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

The Upper Paraná basin has the largest number of dams in South America, which causes changes in the hydrodynamics of rivers and obstruction of fish migratory routes. These dams provide areas for the implementation of cage fish farming systems, which can cause environmental influences related to the entry of organic matter into the aquatic ecosystem. Assessing the influence of fish farms on the ichthyofauna usually use traditional methods of analysis, ignoring the role of species in the community. Thus, functional analysis can be a more effective way to assess environmental influences, such as cage fish farms. The present work will test the following hypothesis: cage fish farms cause changes in the functional diversity of wild ichthyofauna. The study area belongs to the Chavantes Reservoir, Paranapanema River, and upper Paraná River basin. The samplings were carried out in three cage fish farming systems (FF1, FF2, and FF3) and in three reference areas (RF1, RF2, and RF3), located upstream from the fish farms. Collections were carried out monthly from December 2006 to November 2007 (FF1, FF2, RF1, and RF2), and from March 2008 to February 2009 (FF3 and RF3), using gill nets. To assess whether there were changes in the functional diversity of the ichthyofauna, the functional richness indices (FRic), functional uniformity (FEve), functional divergence (Fdiv), functional dispersion (FDis), and functional redundancy (FRed) will be calculated, in addition to the diversity analysis ² functional. The average of the functional attributes weighted by the abundances in the communities (CWM) will also be calculated, to verify which functional attributes were more important in each evaluated area. It is expected to generate information on the environmental influences of cage fish farms on the ichthyofauna, in addition to proposing ways of analyzing such influences, directly related to the functioning of the ecosystem and not only to the presence and absence of species.(AU)