Trophic ecology of the Patagonian skate, Bathyraja macloviana, on the Argentine continental shelf

SCENNA, L. B.; GARCÍA DE LA ROSA, S.B.; DÍAZ DE ASTARLOA, J. M.

ICES JOURNAL OF MARINE SCIENCE

OXFORD UNIV PRESS

Año: 2006 vol. 63 p. 867 - 874

1054-3139

The diet, feeding strategy in terms of specialization-generalization, and dentition of the Patagonian skate, Bathyraja macloviana, on the northern Argentinean continental shelf were studied from the by-catch of research cruises. Of a total of 81 stomachs examined, only 3.7% were empty. The quantitative analysis, graphical method and niche breadth indicated that the Patagonian skate in the northern Argentinean continental shelf is a specialized feeder. The most important prey item was polychaetes followed by gammarid amphipods, isopods and crabs. Cumaceans, ophiuroids and hydrozoans appeared to be infrequently present in stomach contents of mature females, suggesting that these prey items were likely incidentally consumed. The small weak jaws of B. macloviana are suitable for feeding on polychaetes and soft-shelled crustaceans. Sexual dimorphism in the dentition of mature males and females was found, being tooth cusps of mature males longer and sharper than both females and immature males. However, a high degree of overlap between mature males and females was found, suggesting that dental sexual dimorphism in this species would be more important in reproductive behaviour than in differential niche utilization.