Feeding habits of thresher sharks Alopias sp. in northern Peru: predators of Humboldt squid (Dosidicus gigas)

Abstract

The stomach contents of thresher sharks (Alopias spp.; 162–385 cm total length) were collected from five landing points in northern Peru during 2015. A total of 128 thresher sharks were sampled, with 38 individuals identified as Alopias pelagicus and 90 aggregated to the genus level Alopias sp. to prevent any misidentification. The diet comprised 13 and 10 prey taxa for Alopias sp. and A. pelagicus, respectively. Humboldt squid Dosidicus gigas dominated the diet of both groups, with only minor differences in the diet in relation to size classes and location. The diet of Alopias shows a high degree of specialization and the average trophic positions were high for both groups, A. pelagicus (4.4 ± 0.13) and Alopias sp. (4.5 ± 0.14).