Food habits of Discopyge tschuddi (Chondrichyes, Narcinidae) off north Argentina and Uruguay.

SPATH, CECILIA; BARBINI, SANTIAGO A.; COLONELLO, JORGE; FIGUEROA, DANIEL E.

Portland, E.E.U.U.

Congreso; Joint Meeting of Ichthyologists & Herpetologists; 2009

American Society of Ichthyologists and Herpetologists - American Elasmobranch Society

The apron ray, Discopyge tschudii, is abundant and common species from the coast of southern South America. Diet composition and feeding strategy of this species were investigated through stomach content analysis. The specimens were collected from research cruises carried out by Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP) and commercial landing between 2005-2008 off north Argentina and Uruguay (34°S - 41°S). Stomachs were frozen to -20ºC. Prey were counted, eighted, and identified to the lowest possible taxonomic level. Of a total of 342 stomachs examined, 88.3% contained food. According to the Index of Relative Importance expressed as a percentage, polychaetes (96.36%) were the most important prey group in the diet of D. tschudii. Minor importance had siphons of Amiantis purpurata (2.61%) and amphipods (1.03%). The graphical method of prey-specific abundance against requency of occurrence suggested that D. tschudii displayed a clear specialisation toward polychaetes. However, when the polychaetes are grouped by their life style (sedentary:%IRI = 21.92; errant: %IRI = 31) a mixed feeding strategy is observed. Our results show that D. tschudii feeds exclusively on benthic invertebrates.