Freshwater biodiversity is declining at alarming rates. In a large-scale effort, a research team led by IGB and the Humboldt Universität zu Berlin (HU) in cooperation with angling clubs, has conducted whole-lake experiments in 20 lakes to improve ecological conditions. Habitat improvements were the most effective means to enhance fish populations, whereas fish stocking completely failed. The study published in the journal Science emphasizes the importance of restoring habitats and improving natural ecosystem processes, which benefits fish populations, conservation and fisheries.