Predation of the invasive freshwater mussel Limnoperna fortunei (Dunker, 1857) (Mytilidae) by the fish Leporinus obtusidens Valenciennes, 1846 (Anostomidae) in the Rio de la Plata, Argentina

A study of the presence of the freshwater mussel Limnoperna fortunei in the diet of the native fish Leporinus obtusidens was performed in Costanera No rte. Buenos Aires. Fish were collected monthly for a 1-year period to analy ze their digestive tracts. From a total of 157 fish collected (20-55 cm tot al length), 21 had empty digestive tracts. Of the remaining 136 individuals , 98 (72.1%) contained fragments of Limnoperna shells. The mussel represent ed 14.5% of the stomach content dry weight and 44.4% of the intestinal cont ent dry weight. Limnoperna was present in almost all fish over 30 cm (total length). The largest number of mussels ingested by a Leporinus individual was 77, estimated by mussel beak count. Mussels 15-20 mm in shell length to be the most abundant in Leporinus digestive tract.