Large fluctuations in water levels, caused by a nearby hydroelectric plant, and water pollution from mining activities have caused the population of grebes to fall from 1000 in 1961 to around 200 in 2007. Contamination of the lake from mining waste products kills the small fish that are the Junin grebes main source of food. The hydroelectric plant can cause the water level to drop below 5m, which prevents the birds from raising chicks, and can cause damage to the bordering reed marshes.