| Compound indices are often used in the analysis of fish stomach contents to characterize diet. Five of these indices, combining two or three measures of prey importance: weight, abundance and frequency of occurrence, are mathematically compared in this work. Data from a feeding study of sparid fish show that different indices can produce different results. Four classifications of food, in terms of preferences, are applied to Sparidae, compared and discussed. A new method of classifying the prey of fish into groups is proposed. It characterizes the main items in the diet, whatever feeding index is chosen for the analysis. |
