Lengthz-Weight Relationship and Condition Factor of Coelotilapia joka (Thys van den Audenaerde, 1969) in the Rokel/Seli River, West Africa

Abstract

This study was conducted in the lower, middle and upper reaches of the Rokel/Seli River, Northern Sierra Leone. There is a research gap on the growth or wellbeing of tilapia fish species in Sierra Leone. The objective of this study is to determine the length-weight relationship and condition factor of Coelotilapia joka from the main river channel. This research could contribute to promoting an agenda for fish culture practices for the fish. A total of 228 specimens of Coelotilapia joka were collected using gill nets. Fish length and weight measurements were done using fish measuring board and digital weighing balance respectively. Measurement for water quality was made using the Jemway multi-parameter water quality measuring device (Model: J970, Barloworld Scientific, United Kingdom). The values for regression coefficient “b” gave 2.5437, 2.1841 and 2.4585 for males, females and combined sex respectively, implying a negative allometric growth in the fish at (b<3.0). Similarly, a strong positive linear correlation “r” exists for male (0.947) and female (0.827) species of C. joka. Mean condition coefficient (K) was 2.113 ± 0.309 for males and 1.969± 0.359 for females. The lowest condition factor for male,1.995 and female,1.743 were recorded in March and April respectively, and the highest, 2.552 and 2.067 recorded in August. These values, however, suggest that the fish was in good condition (K>1). The difference in ‘K” for both sex is significant (p<0.05). A study for a period of one year could, however, provide a complete analysis of seasonal variations in growth and condition of the fish.