Feeding habits of two deep-sea sharks from centralnorthern Chile: hooktooth dogfish Aculeola nigra (Etmopteridae) and dusky catshark Bythalaelurus canescens (Scyliorhinidae)

Feeding habits of 381 specimens of Aculeola nigra and 513 specimens of Bythalaelurus canescens were studied. In 121 stomachs of A. nigra and 312 of B. canescens preys were found. Individuals were collected as by-catch from the deep-sea crustacean fishery, between 25º20'S and 35º43'S; from January 1997 to July 2000 off the northern-central Chilean coast. The most important prey by index of relative importance and by frequency of occurrence in A. nigra was the benthic deep-sea shrimp Heterocarpus reedi; while by number the euphausiid Euphausia mucronataand by weight the common hake Merluccius gayi were the most important. The deep-sea shrimp H. reedi was also the most important prey of B. canescens, for all feeding indices used. Significant differences were found in the habitat where these predators consume their prey, A. nigra eating more on pelagic prey; whereas B. canescens feeds more on benthic prey. A. nigra showed a higher trophic niche breadth, because they predate more on benthic, pelagic and mesopelagic resources; whereas B. canescens feeds primarily on benthic prey. The diet of both species significantly overlapped, suggesting a high competition between them.