Food and diet relationships of Parachanna obscura (Gunther) and Clarias gariepinus (Burchell) in a newly impounded Osinmo reservoir, Ejigbo, Nigeria

Abstract

The food and diet of two economically important freshwater fish species, Parachanna obscura and Clarias gariepinus were examined in Osinmo reservoir. Gill-net, cast-net and traps were the fishing gears used to collect fish specimens. Morphometric parameters of each fish were taken. Stomach fullness was noted and each stomach preserved in 4% formalin. Frequency of occurrence and Numerical methods was used to analyse the stomach contents of each fish. The study observed by frequency of occurrence that insects, fish, and algae, constituted 73% of the stomach contents of P. obscura throughout the sampling period. Similarly the stomach contents of C. gariepinus were dominated to the tune of 79% by detritus, mud, fish, algae, insects and diatoms. Slight variation in food items was observed during the dry and rainy seasons. The percentage of non- empty stomachs in dry and rainy seasons increased from 80% to 89% in P. obscura and from 74.6% to 83.4% in C. gariepinus. The two species of fish fed on many related food items and Schoener overlap index values of 0.05 and 0.02 indicated no diet overlap and competition in dry and rainy seasons.