Impact of the use of Toxic Plants (Brugmansia spp.) in illegal fishing of the Nile Tilapia Species (Oreochromis niloticus).

Abstract

Illegal fishing, often carried out using destructive methods, has generated serious ecological and socioeconomic problems, compromising the sustainability of water resources and the health of local communities. This work investigates the impact of the use of toxic plants, mainly of the Brugmansia genus, in the illegal fishing of Nile tilapia (Oreochromis niloticus). The study addresses the use of Brugmansia spp., which, when released into the water, cause the death of fish, facilitating their capture. This practice, although apparently advantageous for fishermen, has serious consequences, such as the contamination of aquatic ecosystems, reduction of biodiversity, and risks to human health, since the ingestion of contaminated fish can lead to serious health problems. The research was carried out through a literature review and direct observation in four experiments (circular and rectangular basins), in addition to analysis of water samples. The results showed a clear dose-dependent relationship between the concentration of Brugmansia spp. extract and the increase in tilapia mortality. At lower concentrations (5 g), overall survival was maintained, suggesting a tolerance threshold. However, as plant concentration increased, the number of dead fish rose rapidly, with evidence of acute mortality at high levels (30 g and 44 g). The study concluded that illegal fishing with toxic plants not only compromises the sustainability of Nile Tilapia, but also puts the health of communities’ dependent on fishing at risk. And, it suggests the implementation of public policies aimed at monitoring fishing and awareness campaigns, aiming at protecting ecosystems and promoting sustainable fishing practices.