STUDIES ON THE GROWTH AND REPRODUCTION IN THE CICHLID Oreochromis niloticus (LINNAEUS, 1757) IN A EARTHERN POND

Abstract

A total of 1,300 fingerlings of O. niloticus, 3 months old, were stocked in a fertiIized earthen pond of 1,300 m² at Pindamonhangaba Fish Culture Station - S. Paulo, BraziI. During the experiment period, a total of 478 fish were measured, weighed and dissected to record their sex and stage of maturity. The biometric relationships, the growth and maturation curves and the condition factor were analyzed and related with water temperature. The growth in males is faster than in females and is directly related with the water temperature. The maximum spawning activity extends from September to November and there are more than one spawning action in a season. The weight of the ovaries produces significant changes in the condition factor, and this observation suggests that, as the difference between the condition factor, estimated with (K_I) and without (K_II), the weight of the ovaries (K = K_I - K_II) indicates the "gonad condition" and can be used as a maturity and breeding season index.