Differential feeding by sardine dinops sagax anchovy raulis capensisruits in mixed shoals

Abstract

In a first effort to understand interactions between anchovy Engraulis capensis and sardine Sardinops sagax in the field, the size composition of the diet of these two species from a number of mixed shoals was examined.
Although both species consumed similar types of food (crustacean eggs and nauplii, and copepods), sardine generally consumed significantly smaller prey (modal size-class generally 300 ìm) than anchovy (modal sizeclass
generally between 600 and 900 ìm). No single explanation can be used to account for these results, and it is suggested that they are the product of differences in gill-raker morphology, feeding behaviour and within-
shoal position. These results support previous single-species laboratory studies and suggest that competition between the two species in the field may be limited.