Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high middle-level trophic positions in the food web. They represent important sources for fisheries Ecuador. Despite their ecological economic importance, studies on pelagic species Ecuador are scarce. This study uses stable isotope analysis to assess ecology of these species, determine contribution prey predator tissue. Isotope data was used test hypothesis that medium-sized fish have higher δ15N values than those they consumed, there is no overlap between δ13C values. Results showed K. followed by T. which indicates highest position this web occupied audax. The Bayesian ellipses demonstrated a long time-scale, do not compete sources. Moreover, were different decreased with decrease size.