The Diets of the Spiny Dogfish Species (Squalus acanthias, S. mitsukurii and S. cubensis) From the Northern Argentinean Continental Shelf

BELLEGGIA MAURO; FIGUEROA DANIEL E.; MASSA ANA; BURGESS GEORGE; BREMEC CLAUDIA

Chattanooga, Tennessee

Congreso; Joint Meeting of Ichthyologists and Herpetologists; 2014

American Society of Ichthyologist and Herpertologists

In the southwest Atlantic Ocean inhabit three Squalidae species: Squalus acanthias, S. cubensis and S. mitsukurii. In spite of the diet of the former was widely studied in Argentina and worldwide, the trophic ecology of S. cubensis and S. mitsukurii remain unknown. In this context the diets of these two species were studied based on analysis of stomach contents from specimens caught during three research cruises on the northern Argentinean continental shelf (34° S ? 41° S). Prey items were identified to the lowest possible taxonomic level, counted and weighted. A total of 214 specimens of S. cubensis were analyzed from which 176 (82.24%) contained prey items. From 414 specimens of S. mitsukurii analyzed, 289 (69.80%) contained food in their stomachs. Squalus mitsukurii fed on fish (%IRI=54.1%), crustaceans (%IRI=25.04%) and cephalopods (%IRI=18.89%). The argentine anchovy Engraulis anchoita, the argentine hake Merluccius hubbsi and hagfishes Mixinidae were among the most important identified fishes. The euphausiids were the most consumed crustaceans, whereas Illex argentinus, Loligo sanpaulensis were the preferred cephalopods. On the other hand, the diet of S. cubensis was composed mostly by fishes (%IRI=84.96%), followed by crustaceans (%IRI=9.99%) and cephalopods (%IRI=1.99%). The most important prey items identified in the diet of S. cubensis were the same to those found in S. mitsukurii, but differed in proportions. The hypotheses that the diet is determined by intrinsic (total length, sex, maturity) and extrinsic factors (area, season) were tested by fitting generalized linear models (GLMs).