Ovarian differentiation in common carp (Cyprinus carpio) in relation to growth rate

Growth rate is influenced by density-dependent factors and in turn may affect the ontogeny df some systems. Population density gradients were established in common carp nursery ponds to develop differential growth rates. Ovarian development at the anatomical and cytological stages of differentiation were examined in relation to growth. Size at the end of 66 +/- 2 and 155 +/- 5-day periods was inversely related to population density, and the size/age relationship of differentiation of the ovary was affected. Mitotic gametogenesis was initiated sooner within-populations with more rapid growth but generally at larger sizes than in populations with slower growth rates. Application of this phenomenon can be important to selection of appropriate size and/or age of common carp and to determine the required duration of androgen-induced sex reversal treatments.