title: Reproductive biology of female Nile tilapia Oreochromis niloticus (Linnaeus) reared in monoculture and polyculture with African sharptooth catfish Clarias gariepinus (Burchell).
abstract: This study was conducted to assess the reproductive biology and early breeding behaviour of female Oreochromis niloticus reared in monoculture and polyculture with Clarias gariepinus in earthen ponds for 8 months. Results revealed no significant difference in length at first maturity (L50) between females reared in monoculture and polyculture systems. Similarly, no significant differences were detected in absolute fecundity, relative fecundity, gonado-somatic index and condition factor between the two culture systems. The absolute fecundity was more strongly correlated with total length and body weight than with ovary weight. The study concluded that early breeding of O. niloticus in captivity is not affected by the culture systems used. Therefore, O. niloticus production in either system can be improved only through proper pond management techniques.
authors.affiliation: Tanzania Fisheries Research Institute, Institute Headquarters, P. O. Box 9750, Dar es Salaam, Tanzania.
authors.forename: A P
authors.initials: AP
authors.lastname: Shoko
authors.affiliation: Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P. O. Box 35064, Dar es Salaam, Tanzania.
authors.forename: S M
authors.initials: SM
authors.lastname: Limbu
authors.affiliation: Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P. O. Box 35064, Dar es Salaam, Tanzania ; Tanzania Fisheries Research Institute, Mwanza Centre, P. O. Box 475, Mwanza, Tanzania.
authors.forename: H D J
authors.initials: HD
authors.lastname: Mrosso
authors.affiliation: Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P. O. Box 35064, Dar es Salaam, Tanzania.
authors.forename: Y D
authors.initials: YD
authors.lastname: Mgaya
keywords: Early maturation; Fecundity; Grow-out ponds; Ovary weight; Prolific breeding; Tilapia culture systems