Acta Ichthyologica et Piscatoria 23(2): 33-54, doi: 10.3750/AIP1993.23.2.02
Fecundity and reserve of the oocytes of protoplasmatic growth in the ovaries of bream, Abramis brama (L.), females in two Konin lakes
expand article infoW. Kopiejewska, M. Jankun, I. Mrowińska
Open Access
Lakes Gosławskie and Ślesińskie are two out of five Konin lakes which receive a discharge of heated effluents from “Pątnów” 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 Gosławskie in warmer than Lake Ślesińskie: in about 46% of bream females from this lake percentage of maturing oocytes in the ovaries was higher than in Lake Ślesińskie (and than in natural conditions), 20-38.8%. Increased temperature in Lake Ślesińskie 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 Gosławskie 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.