Morphometric and Meristic Variations in Tilapia guineensis (Bleeker 1862) and Sarotherodon melanotheron (Ruppell 1852) from Badagry and Lagos Lagoons in Nigeria

Abstract

Sarotherodon melanotheron and Tilapia guineensis are two dominant cichlids in the Badagry and Lagos lagoons in South-western Nigeria. Comparative racial studies were carried out among these species using multivariate analysis of 9 morphometric characters and 9 meristic counts of 100 specimens for each species from each lagoon. The results showed that the 2 species from the 2 lagoons were phenotypically separable populations with some levels of divergence in morphometric characters. The data were analysed using independent sample t-test after allometric test revealed significant differences (P < 0.05) in body depth, caudal peduncle depth and number of gill rakers in Sarotherodon melanotheron while vertebrae, caudal peduncle depth and right gill raker counts in Tilapia guineensis, which could have occurred as a result of environmental fluctuations, genetic diversity and differences in salinity in the 2 water bodies.