Trophic ecology of Squatina guggenheim on the continental shelf off Uruguay and northern Argentina

A total of 1280 (670 females and 610 males) Squatina guggenheim , an angel shark endemic to the south-west Atlantic, was caught during five research cruises (1995, 1997 and 1998) carried out in the Argentine-Uruguayan Common Fishing Zone (AUCFZ) at depths of 3·5–266 m. All angel sharks captured were sexed and measured. Of the 947 examined for stomach contents, 556 (58·7%) contained food and 391 (41·3%) were empty. Numerically, bony fishes were the principal dietary component (89·7%), followed by crustaceans (4·8%) and molluscs (4·4%). The most important prey species were Engraulis anchoita (58·3%), shrimps (4·4%) and Ilex argentinus (2·3%). Male and female diets were not found to differ significantly ( P  > 0·01), however, the diets of different size classes showed significant differences ( P  ≤ 0·01) (group 1, 23–44, group 2, 45–74 and group 3, 75–91 cm L _T). Low rates of cannibalism were observed. The spatial and seasonal variability in the trophodynamics of S. guggenheim is discussed.