Benthic macroinvertebrates as indicators of water quality in aquaculture in Lake Guamuez, Nariño, Colombia.

Global aquaculture continues to grow, displacing capture fishing, a behavior that is reflected in Colombia through the cultivation of species such as red tilapia (Oreochromis sp.) and rainbow trout (Oncorhynchus mykiss), generating good quality protein for human consumption. However, production generates environmental impacts on water and lake ecosystems. This study determined water contamination in three rainbow trout farming companies in floating cages in the upper, middle and lower part of the RAMSAR Lago Guamuez wetland. Sampling was carried out in high and low rainfall, in six areas (three companies and three control points). Benthic macroinvertebrates were taxonomically identified, being used as bioindicators, calculating biological diversity indices such as Shannon diversity, Pielou evenness, Berger-Parker dominance and Margalef richness. In cultivation areas A, B and C, species tolerant to a certain degree of contamination such as Chironomidae, Thiaridae, Ampullariidae and Planaridae were found, while in control points A1, B1 and C1, species such as Libellulidae, hydrobiosidae and Hydrachnidae were found, which are less tolerant, indicating better water quality. The indices showed that there is an environmental impact caused by the productions, however, the presence-absence of species tolerant to a certain degree of pollution may be due to aquaculture productions and other anthropogenic activities such as tourism, wastewater, agricultural crops and oil spills. fuel of. Although it is true that the Lake is classified as oligotrophic, alarms must be raised to allow for its good management and preservation.