Kopiejewska W., Jankun M., Mrowińska I., 1993. Fecundity and reserve of the oocytes of protoplasmatic growth in the ovaries of bream, Abramis brama (L.), females in two Konin lakes. Acta Ichthyol. Piscat. 23 (2): 33-54.

Lakes Gos-awskie and ęlesi±skie are two out of five Konin lakes which receive a discharge of heated effluents from “Pśtnów” and “Konin” power plants. In these two lakes bream females are characterized by single portion spawning. 25% of the females tend to batch spawning. Lake Gos-awskie in warmer than Lake ęlesi±skie: in about 46% of bream females from this lake percentage of maturing oocytes in the ovaries was higher than in Lake ęlesi±skie (and than in natural conditions), 20-38.8%. Increased temperature in Lake ęlesi±skie caused intensive development of eggs in the ovaries of young females, 3-7 years old, so that they passed from the class of moderately growing to the class of rapidly growing. In Lake Gos-awskie maturation of eggs in the ovaries of 4-6 year old females became even more intensive, so that they passed from the class of slowly growing to the class of more than moderately or rapidly growing ones.