ABSTRACT
Carps have a very high biotic potential, a gravid female being capable of producing in excess of a million eggs in one spawning when fully grown. Eggs and semen are released into the water to the accompaniment of spectacular sexual behaviour whereby the males and females synchronise their bodily contractions to excrete their sex products. As far as quantity of eggs is concerned, the use of histological techniques has considerable limitations and for accurate estimations of egg numbers maceration and total and differential counts are required. The cytomorphological state of the follicles in the ovary thus coincides with the physiological state of the animal, and it is only the lack of external cue stimulus which prevents spawning in autumn, and the quantity of eggs produced is perfectly acceptable. In farmed fish, females which are subjected to seasonally controlled propagation, and therefore normally only produce one spawn, will produce around 400,000 eggs per year.
