Comparative Food and Feeding Adaptations of Two Teleosts in Ado-Ekiti Reservoir

A comparative study of food and feeding adaptations of Clarias gariepinus (40.6-47.6cm) and Oreochromis niloticus (8.4–20.5cm) in Ado Ekiti reservoir was carried out using numerical, frequency of occurrence, volumetric assays and physical observation of the morphological features. The mouth gape and dentition, spacing and number of gill rakers as well as the length of O. niloticus and C. gariepinus wer significantly different from one another. The food items in the gut of O. niloticus include; detritus/mud, higher plant remains, Chlamydomonas, Closterium, Spirogyra, Volvox and insect parts. C. gariepinus were found to feed mainly on crustaceans, insects, molluscs, fish, detritus, algae and vegetable matters. The results reveal high level of similarities in the diet of O. niloticus and C. gariepinus. However, O. niloticus had more of higher plant (76.96% by numerical method) than C.gariepinus, indicating high herbivorous feeding in tilapia while C.gariepinus had higher occurrence of insect and fish parts (36.76%), thus highlighting omnivorous habit. The mouth gape, dentition, spacing and number of gill rakers and gut length of O. niloticus and C. gariepinus were significantly different (p<0.05) from one another. C. gariepinus and O. niloticus in Ado Ekiti reservoir are essentially omnivores and herbivores respectively, with some overlapping food preference. However, the different major food items fed upon by the species and the corresponding adaptations to feeding makes co-existence of the two species, amongst others, possible, and would ultimately reduce intense competition.