Morphometric Characters and length weight relationship of Oreochromis niloticus in southwest of Algeria

Oreochromis niloticus also called “chicken of aquaculture” is a fresh and brackish water fish recognizable among all other tilapias by continuous black stripes on the caudal fin. Morphometric characters of Tilapias were reported in Egypt, Turkey, Nigeria, Sri Lanka. In Algeria, studies on tilapia have treated the species Tilapia zillii, its morphology (Guezi et al. unpublished study) and its reproduction (Guezi et al, 2021). The Biometry of the nil tilapia Oreochromis niloticus of the south westof Algeria was studied from December 2020 to November 2022. A total of 220 individuals, whose total length varied between 3 and 21 cm and weight between 22.9 and 289.7 g, were examined. The percentage of the different morphological measurement in relation to the total length of the fish, the regression equation and the length weight relationship was calculated. Six (6) characters showed a positive allometry, seven (7) characters showed a negative one, while only the height of the caudal peduncle showed an isometry. The length weight relationship was expressed as: LogW = 2.458 Log TL – 1.061. This study presents the first results of the morphometry of O. niloticus in the south-west of Algeria, and must be completed by studies on age and reproduction.