Energy utilization during ovarian development of the cichlid fish Oreochromis mossambicus (Peters) inhabiting a perennial lentic water body in Bangalore, India

Abstract

Mozambique tilapia Oreochromis mossambicus (Peters) is an invasive fish and a continuous breeder in inland waters of India. Present investigation highlights the distinct developmental stages of developing ovary and associated changes in the energy content. This investigation helps to understand the allocation of energy for development of eggs, prespawn and also oral brooding by the female. Although it is a continuous breeder, based on size of the ovary, number of eggs, their size and energy content, immature, early maturing, developing, prespawning and spawning stages are clearly noticed. Egg diameter during development of ovary varied between 0.31 mm (immature) and 2.21 mm (spawning). Energy content of ovary from immature to spawning stage ranged from 20.7515 kJ g À1 dry ovary to 31.1560 kJ g À1 dry ovary.Nearly 28.73% of energy content of ovary is expended for spawning. Similarly, yolksac fry utilized nearly 25.85% of energy of the fertilized egg for its development.