Abstract

• Nile tilapia Oreochromis niloticus was carried out to assign the classification of local population relation to their biometric parameters. A total of 265 samples were collected from five markets in Meiktila. Biometric characters of eleven meristic counts and seventeen morphometric traits were generated with Principal Component Analysis (PCA). The result shows the meristic characters of O.niloticus did not change with any increasing in relation to variable morphometric parameters. Analysis of variance (PCA) revealed the two components with 86.85 % (λ=14.76) at Taw Ma market, 86.43 % (λ=14.69) at Wun Zin market, 84.67 % (λ=14.39) at Pauk Chaung market, 83.44 % (λ=14.18) at Myo Thit market and three components with 80.66 % (λ=13.71) at Myo Ma Central market. Coefficient determination R2 revealed variable significant relationships in total length and other body parts among population, however, with head length relationship showed low correlation in interorbital width (IOW) and mouth length (ML) in all markets. The most striking pattern of hybrid tilapia was found in Pauk Chaung market and Myo Thit market. These pilot surveys strongly suggest the local population of non-indigenous Nile tilapia O.niloticus with the existence of morphological differentiations among population. In addition, the pure population of tilapia species is urgently needed to maintain without hybridizing with other species in Meiktila Environs.