Fecundity of roach (Rutilus rutilus L.) in heated Lake Gosławskie

Abstract

Studies were carried out on the effect of long-term lake heating upon the fecundity of roach. Fecundity increased noticeably due to more rapid growth of the fish, but also to higher number of eggs produced by the females (on the average from 154 to 199 eggs per 1 g of body weight). Age of attaining the first maturity changed and life span of the fish shortened, leading to changes in age structure of the population.