Effect of body condition on the reproductive index of Sarotheredon melanotheron in Niger Delta, Nigeria

Abstract

The effect of bo'dy condition on the reproduction of Sarotlzeredon melanotheron was examined to determine if a relationship exists between body condition and readiness to spawn in both sexes. Sixty two fish comprising 27 females and 35 males were examined. Total length and body depth were measured to the nearest lcm while body weight and gonad weight were weighed to the nearest 0.1g and O.OO1g respectively. Gonadonsomatic index (GSI) and the condition factor (K) were calculated and the percentage values statistically evaluated. There was no significant correlation (P>0.05) of body condition and body depth with gonadosomatic index of female S. melanotheron. On the other hand, body condition and depth were highly correlated (P>0.01) with gonadosomatic index in the male fish. However, the correlation of body length on gonadosomatic index was significant (P<0.05) in both sexes. It is therefore concluded that total length may be an important factor in determining spawning success in both sexes, while condition factor and body depth may be employed as additional tools in determining spawning success in male S. melanotheron only.

Key Words: Sarotheredon melanotheron, Gonadosomatic index Condition factor and spawning relationship.