1. Indices of Gut Content Analysis

2. Index of Relative Importance (IRI)
Relative importance of various food items, based on the frequency of occurrence, number and volume of each item, this can be determined by:
IRI = (% N + %V) %F
Absolute Importance Index (AI)
AI = %F + %N + %W

3. Comparative Feeding Index
This is a combination of the points method and the relative importance method and depends on the volume, fullness and frequency of each food item.
This method involves the allotment of points to each food organism and the mean value per fish is multiplied by the percentage of total fish sampled.
Index of Preponderance
Based on the volume and the occurrence index.

4. Gastrosomatic Index (GoSI)
GoSI = weight of the stomach / weight of the fish * 100
This index is very low during the peak spawning season because of the more number of empty stomachs.
The rise and fall of gastrosomatic index always show an inverse relationship with the Gonadosomatic Index