Stock Photo - 21 November 2022, Saxony-Anhalt, Thale: Two professional fishermen sail across the Rappbode Dam in a boat. They set their nets to fish the dwarf whitefish out of the lake. The small fish was used in the 1960s, as potential food for the large predatory fish. The reproductive power of the dwarf whitefish was underestimated at the time. It is estimated that dwarf whitefish now make up about 95 percent of the biological fish mass in the reservoir. In the long run, this could become a threat to water quality. Therefore, about 3 tons of the lesser whitefish are fished out of the lake every year. Photo: Matthias Bein/dpa/ZB. - Thale/Saxony-Anhalt/Germany