Condition factor and length-weight relationship of Bagrus bayad macropterus (Daget, 1954) from Agbura River, Niger Delta, Nigeria

Abstract

The study on length-weight relationship and condition factor of Bagrus bayad macropterus from Agbura River, a tributary of the Nun River was conducted monthly for eighteen months (April 2012 – December 2013). Three thousand, six hundred and forty (3640) fish samples comprising of one hundred and ninety-three (193) Bagrus bayad macropterus were collected using traditional fishing gear and drag nets. The specimens were preserved in ice-packed box and taken to laboratory for length-weight measurement. The length-weight relationship was estimated using the linear regression model 𝑊=𝑎𝐿𝑏 and condition factor (k) determined using the equation 𝐾=100𝑊𝐿𝑏 .The standard length ranged between 17.6 and 27.2 cm and the weight ranged between 170.56 and 501.30 g in males and 16.8 to 32.2 cm and 190.60 to 510.35 g in females. The value of length exponent was more than 3 showing positive allometric growth pattern. The b-values tested using ANOVA indicated a highly significant regression of weight on standard length (P<0.05). The correlation (r) between increase in length and gain in weight was significant. The condition factor ranged between 1.51 and 3.13 with mean k-value of 2.23. The k-values showed monthly variations with peak values between the months of January and April. The fish species was in good condition in the study area as the K values were above one throughout the period of study.Keywords: Condition factor, length- weight relationship, Bagrus bayad macropterus, Agbura River Niger Delta