Length-weight relationship and condition factor of Sarotherodon melanotheron and Tilapia guineensis in Lagos Lagoon, Nigeria

The length-weight relationship and condition factor of Sarotherodon melanotheron and Tilapia guineensis inhabiting Lagos lagoon were examined and the relationship among the parameters was determined by correlation. The mean total length and weight was 16.33±2.24cm and 71.44±30.04g for S. melanotheron and 16.08±2.92cm and 84.93±44.24g for T. Guineensis, respectively. The regression coefficient (b) of length and weight revealed that S. melanotheron exhibited negative allometry (b=2.36; a=-2.39; R2=0.67) while T. guineensis exhibited positive allometry (b=3.19; a=-4.54; R2=0.87). The condition factor which measures the physiology (wellbeing) of fish was greater than 1 for the two species although, it was higher in T. guineensis (2.04) than S. melanotheron (1.64). This difference may be due to variation in the weights of the two fish species as well as environmental factors in the lagoon. The study revealed that both species were healthy despite that Lagos lagoon receives wastewater from different anthropogenic sources. This shows that the study area is conducive for the development and sustenance of fisheries resources.