Impact of treated effluent discharges on fish communities: Evaluating the effects of pollution on fish distribution, abundance and environmental integrity

DI PRINZIO, CECILIA YANINA; ANDRADE-MUÑOZ, ALAN SEBASTIÁN; ASSEF, YANINA ANDREA; DROMAZ, WALTER MAURICIO; QUINTEROS, PAMELA; MISERENDINO, MARÍA LAURA

THE SCIENCE OF TOTAL ENVIRONMENT

ELSEVIER

Año: 2024 vol. 917

0048-9697

Domestic effluent discharges change water quality and habitat conditions in urban watersheds, though less known about how these impact fish communities. This work assessed the impact of chronic wastewater pollution on biotic and abiotic factors in six urban streams in Patagonia. Stream hydrological features, water quality conditions and fish communities were analyzed during a one-year period. The oxygen saturation and water velocity showed significant differences between up- and downstream locations of wastewater treatment plants (WWTPs). Chemical parameters revealed an eutrophication process downstream of the WWTP input, with increased biological oxygen demanding (BOD), nitrogen, ammonium, soluble reactive phosphorus, and chloro- phyll a concentrations, indicating nutrient enrichment that can lead to a potential for algal growth. The study highlighted significant differences in fish abundance, density, and biomass between reaches upstream (Control) and downstream (Impacted) of the WWTP discharges, suggesting a detrimental impact on fish communities. While juveniles, females and males of the native Catfish (Hatcheria macraei) preferred pristine zones, juveniles and males of the native Perch (Percichthys spp.) displayed preferences for areas with higher nutrient levels. Exotic species like Rainbow Trout (Oncorhynchus mykiss) (juveniles, females and males) preferred low-nutrient, high- quality habitats, while juveniles, females and males of Brown Trout (Salmo trutta) were found near the WWTP