Table 1. Frequency of occurrence (Qi), volumetric contribution (Vi), and index of preponderance (IOP) of functional prey categories in the diet of Oreochromis niloticus (n = 226) in Lake Shala, Ethiopia

Food type	Qi	%Qi	Vi	%Vi	IOP	IOP%
Phytoplankton	204	90.3	221.3	75.5	31.4	91.0
Zooplankton	87	38.5	42.5	14.5	2.6	7.5
Insects	27	11.9	14.9	5.1	0.3	0.8
Nematodes	24	10.6	2.4	0.8	0.04	0.1
Fish scales	18	8.0	4.6	1.6	0.06	0.2
Detritus	31	13.7	7.25	2.5	0.2	0.5