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

The diet, feeding strategy, and dentition of the Patagonian skate, Bathyraja macloviana, on the northern continental shelf of Argentina were studied from specimens collected during research cruises in September and October 2001. Of a total of 81 stomachs examined, only 3.7% were empty. Cumulative prey curves showed that sample sizes were adequate to describe the main prey items of the diet. Quantitative analysis, a graphical method, and trophic niche breadth indicated the species to be a specialized feeder. The most important prey items were polychaetes, followed by gammarid amphipods, isopods, and crabs. Cumaceans, ophiuroids, and hydrozoans were likely incidentally consumed by mature females. Sexual dimorphism in dentition was observed; mature males had longer and sharper tooth cusps than females or immature males. However, there was a high degree of dietary overlap between mature males and mature females, indicating that dental sexual dimorphism in the species is more important in reproductive behaviour than in differential prey consumption.