Length-weight Relationship and Condition Factor of Tilapia zillii (Gervais, 1884) in Oyan Lake, Abeokuta, Southwest Nigeria
Odulate, Dominic Olaniyi
Department of Aquaculture and Fisheries Management, Federal University of Agriculture, Abeokuta,
P.M.B. 2240, Abeokuta, Ogun State
Length-weight relationship parameters and condition factor of Tilapia zillii in Oyan Lake, Abeokuta, Southwest Nigeria were estimated. The fish catch of the artisanal fishermen operating in the lake were sampled. Fish samples were collected on monthly basis from January to December, 2012. Gears used were cast nets, gillnets and traps. Total length (cm) and weight (g) of the fish samples were measured and their sexes determined. Data obtained were analysed based on sexes and combined using descriptive and regression statistics. Student t-test was employed to test the hypothesis that there is no significant difference ( = 0.05) between the means (total length and weight) of male and female fish. Statistical results revealed that the population of T. zillii in the water body comprised of fish with modal total length of 17.0 cm. The mean total length and weight of male were statistically higher (p<0.05) than female fish. Monthly condition factor was highest in March for male (2.49) and April for female fish (2.14). No significant difference was observed between the mean condition factors of male and female fish. Length-weight analysis depicted negative allometric growth pattern with b-values of 2.90, 2.83 and 2.87 for male, female and combined sexes respectively. Results of Student t-test showed that estimated b-values for male, female and combined sexes were not statistically different (p>0.05) from 3. It can be concluded that Oyan Lake system provides aquatic habitat conducive for good growth of T. zillii in the lake.