Growth parameters of common carp Cyprinus carpio cultivated in semi- closed system

Growth parameters of common carp Cyprinus carpio were investigated in 13 plastic tanks (550 cm diameter and 130 cm depth) of semi-closed system at Abu Al- Khaseeb District, Basrah from 27 October to 17 December, 2016. Number of fishes in every tank was 1300 with an average initial weight 101.9 g. Fishes were fed at a ratio of 5% on sinking pelleted food manufactured in Basrah University factory with 25% protein ratio. Results of current study exhibited highest final weight (381.1 g) achieved by fishes reared in tank number 1 and lowest (326.3 g) in tank number 2. Average fish weight increments for 13 tanks were 248.2 g, with highest weight increment (266.5 g) achieved by fishes reared in tanks 6 and 11, while lowest (222.3 g) achieved by fishes reared in tank number 7. Result also appeared average daily growth of 4.87 g/day, with highest (5.22 g/day) achieved by fishes reared in tanks 6 and 11 and lowest (4.36 g/day) achieved by fishes reared in tank number 7. Average specific growth rate for 13 tanks was 2.44 %/day, with highest (3.10 %/day) achieved by fishes reared in tank number 3 and lowest (1.99 %/day) achieved in tank number 1. Average food conversion rate (FCR) for 13 tanks was 2.12, with highest (2.55) achieved by fishes reared in tanks number 1 and lowest (1.74) achieved by fishes reared in tank number 3.