By 1986 massive blooms of cyanobacteria began occurring, as well as dense populations of roach, a fish that benefited from the pollution's mineral nutrients. Roach eat zooplankton that otherwise keep cyanobacteria in check.
The year 1986 witnessed an increase in both cyanobacteria and roach populations due to the pollution's nutrient enrichment. The roach population benefited from this pollution by consuming zooplankton that normally kept the cyanobacteria in check.