PARASITOFAUNA OF Oreochromis niloticus (Pisces) IN BRAZILIAN WATER OF SANTOS CHANNELS, SP

• Grant number: 24/14014-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: December 31, 2025
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Inland Water Fishery Resources
• Principal Investigator: Igor Paiva Ramos
• Grantee: Fernanda Gabriela Celestino Dias
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

Invasive species are one of the main causes of the loss of biodiversity and ecosystem services worldwide. Oreochromis niloticus is a native fish species from the African continent, but it was widely distributed across several continents and is considered a non-native invasive species in Brazil. Although O. niloticus is well established and commonly farmed in freshwater and brackish environments, records of its occurrence in coastal ecosystems of Brazil have become frequent. This species was recently recorded in the drainage channels in the municipality of Santos, southeastern Brazil. These channels receive clandestine sewage, facilitating the proliferation and transmission of parasites and other pathogens. It is worth noting that there is no scientific information on the parasitic fauna of O. niloticus in brackish waters in Brazil. Thus, this proposal aims to characterize the parasitic fauna of wild specimens of O. niloticus in brackish water in the drainage channels of Santos, state of São Paulo. Thirty specimens were collected in August 2024, in the channel 4, which has a salinity of 17¿. All fish specimens will be euthanized, stored individually in plastic bags, frozen, and transported to the laboratory. They will then be necropsied to remove the organs for parasitological analysis, and the parasites (helminths, crustaceans and hirudineans) will be processed. A computerized image analysis system with phase contrast and a stereoscopic microscope with an attached camera will be used for the morphological and morphometric analyses of the parasites. The parasites will be identified to the lowest possible taxonomic level employing pertinent references. Ecological descriptors of parasitism (prevalence, mean intensity of infection/infestation, and mean abundance) will be determined for each recorded parasite taxon. Richness, diversity, equitability, and parasite dominance will also be determined. The present proposal is expected to contribute new information on the parasitological aspects of O. niloticus and the parasitic fauna of this fish in brackish water environments. In addition to providing data that can help to improve the knowledge on the possible ecological effects of the introduction and invasion of O. niloticus in Brazil, such data can contribute to environmental and health management, especially of the drainage channels studied.