Diet of Pseudechinus magellanicus (Echinoidea:Temnopleuridae) in Argentinean waters.

P. E. PENCHASZADEH, G. BIGATTI, AND P. MILOSLAVICH.

Puerto Varas, Chile.

Congreso; Sea Urchin 2003: Fisheries and Aquaculture,; 2003

ABSTRACT   The gut contents of Pseudechinus magellanicus (Philippi, 1857) collected from different habitats from Buenos Aires to Usuhaia were analyzed. In littoral mussel banks of the Province of Buenos Aires at 50 m depth, the most important food item was Mytilus edulis platensis. In communities without M. edulis the food preferences were Balanus sp., foraminiferans, polychaetes and algae. In beds of the mytilid Aulacomya atra at 5-10m depth, the main food items were the oyster spat and different algae: Rodophyceae, filamentous algae and Ectocarpus sp. In Usuhaia the sea urchin preyed on ostracods, foraminiferans and algae. Our data indicate that P.magellanicus from Argentina is omnivorous, consuming any available food resource: capture drift algae with the tube feet, graze on sessile algae and predate on animals. Results suggest that this species play a relevant role in the community structure, mainly by an intense predation on bivalve spat.