Length-weight Relationships and Condition Factor of Tilapia zillii (Gervais, 1848) from River Orogodo, Delta State, Nigeria

Abstract

The length-weight relationship (LWR) and condition factor (K) of Tilapia zillii from River Orogodo was studied. A total of 569 specimens used in this study were caught with traditional fishing gears from January 2006 to December, 2007. Overall, the allometric coefficient, b of the LWR was found to be negative (b< 3) for both sexes of the species (male, b = 2.58; female, b = 2.80). The condition factor (K) ranged between 1.6 and 4.2 with no obvious variation between males and females. The condition factor however, showed seasonal variation with higher values in the dry than rainy season. The general trend in the condition of T. zillii is that relatively lower condition factor was recorded for larger size classes while relatively higher condition factor was recorded for smaller size classes. The species was in good condition in the river as K-values were generally greater than 1 throughout the study period. The findings from this study will be of use to both fishery managers and culturists interested in the effective conservation and sustainable exploitation of this species.

Key Words: Allometric, parameters, cichlid fishes, fishery management.