Stomach Contents of the Clarias gariepinus (Burchell, 1822) in Lake Geriyo, Yola, Adamawa State, Nigeria

Abstract

The study of dietary habits of fish based on stomach content analysis is a normal practice. The present study aimed to provide information on the stomach contents of Clarias gariepinus in the Lake. On the landing site, fish specimen were randomly sorted and identified using standard keys. In the laboratory. The dissected stomach of each specimen and its degree of fullness was estimated by an arbitrary 0 - 20 point scale: thus 0, 2.5, 5, 10, 15 and 20 points was allotted to empty, trace, quarter-full, half-full, three quarter-full and fully distended stomachs respectively. Stomach contents sorted into categories and analyzed using Relative Frequency (RF) and point’s method. A total of one hundred and sixty two (162) C. gariepinus was examined, 50 (30.86%) had full stomach, 32 (19.75%) had one-quarter stomach full, 31 (19.14%) had empty stomachs, and 26 (16.05%) had half full stomachs while, 23 (14.20%) had three-quarter full stomachs. The composition and distribution of the stomach content of C. gariepinus in Lake Geriyo showed that twenty major classes were identified. The largest group was Chlorophyceae > Cyanophyceae > Branchiopoda > Bacillariophyceae > Copepoda > Zygnematophyceae > Ulvophyceae > Euglenophyta > Dinophyceae > Fragilariophyceae > Ostracoda > Bdelloidea. The Index Food of Significance (IFS) computation showed that almost all the food items were secondary diets (IFS of ≥ 0.1% to <3%) except for Oscillatoria sp. and Moina branchiate (IFS of <0.1%) which were regarded as incidental diet.