Comparación en la dieta de las rayas urotrygon chilensis y narcine entemedor capturadas en los Esteros-Manta.

Abstract

Trophic ecology addresses the interaction between species, with their environment through their feeding, connecting biological and physiological aspects. Batoids, in this context, act as key links in the flow of matter and energy within marine ecosystems. In Ecuador, 10 families of batoids have been recorded, among which we find the round skate Urotrygon chilensis and the electric skate Narcine entemedor. The feeding of these species is related to their morphology and the position of their mouth, which led to a comparative analysis of the diets of U. chilensis and N. entemedor in the Ecuadorian Pacific. The specimens were obtained in the Esteros-Manta area, subsequently analyzed in the laboratory to determine their diet composition with relative importance indexes (%PSIRI). A total of 160 stomachs were analyzed, 80 stomachs of U. chilensis and 80 of N. entemedor, of which 138 were full and 22 were empty. Within the diet composition, 13 prey categories were determined, which consisted of bony fish, polychaetes, crustaceans and unidentified organic matter; the results showed that, in U. chilensis, the most representative food was the crustacean Penaeus vannamei 12.53 %, while N. entemedor showed a clear preference for polychaetes, especially of the family Eunicidae 9.83 % and an overlap index that indicated a considerable coincidence in their preferences.