Food size selectivity and diet overlap in larvae of Clupeiform species from central Chile

The feeding behaviour of larvae of four Clupeiform fish species (Sardinops sagax, Strangomera bentincki, Ethmidium maculatum and Engraulis ringens) was studied using specimens collected from September to November 1987 in Concepcion Bay, Chile. The indices of food preference (α) of Chesson, of diet overlap (D) of Schoener and (L) of Hurlbert, were used. Similar feeding patterns were found in the larvae of the four species. The diet included several developmental stages of copepods: eggs, nauplii and copepodites. The larvae of Engraulis ringens showed an early euriphagy. There were no significant differences in food preference between the species, except for Ethmidium maculatum, which showed a high preference for eggs, even at larger larval sizes. A general trend for preference for larger prey as larvae grow is displayed by the other species. No significant difference was found between sampling periods. A high level of diet overlap was found, regardless of the index used to estimate it.