Spatial- and size-related shifts in feeding habits of the common dolphinfish (Coryphaena hippurus) in the Southeast Pacific Ocean

Abstract

Feeding habits of common dolphinfish (Coryphaena hippurus) were investigated in the Southeast Pacific Ocean using stomach content analysis. Stomachs were collected from 1506 individuals ranging between 18 and 187 cm in fork length. The fish were caught by longliner boats in 2009–2017. Based on percentage of wet weight (%Wi), percentage of number (%Ni), and frequency of occurrence (%Oi), flyingfishes were the predominant prey, followed by the cephalopods jumbo squid (Dosidicus gigas) and argonaut (Argonauta spp.). Permutational multivariate analysis of variance (PERMANOVA) detected significant differences between zones (p < 0.001). PERMANOVA also revealed two size-related shifts in feeding habits to occur at FL ~ 80 cm and FL ~ 110 cm (p < 0.001). Cumulative prey curves did not reach an asymptote in any of the zones and size classes, which may be attributed to the fine taxonomic resolution used. Spatial variations in daily meal ranged between 296.3 and 438.9 g day−1, corresponding to daily ration of 6.1–8.2% body mass BM day−1. Otherwise, size-related variations in both DM and DR were observed. Thus, while daily food intake increased with size from 177.3 for the smallest fish (LF < 80 cm) to 496.7 g day−1 for the largest ones (LF ≥ 110 cm), DR decreased from 13.0 ± 22.1 to 3.7 ± 0.7 BM day−1. The present results contribute to improve the understanding of dolphinfish feeding habits in the Southeast Pacific Ocean.