Cerrano et al. (2000) reported that the Hydractinia angusta Hartlaub, 1904 is epizoic on shells of the Antarctic scallop A. colbecki. It was also found a considerable specific diversity of sponges living on shells of the scallop: Homaxinella balfourensis is the commonest species, followed by Myxilla (Myxilla) asigmata, Lissodendoryx (Ectyodoryx) nobilis, Iophon unicorne and Iophon radiatum (Cerrano et al., 2000). Sponges may increase their dispersal exploiting valves as stepping stones (Cerrano et al., 2009). Another epifaunal community living on the valves of the free-swimming Antarctic scallop is constituted by the calcareous foraminifer Cibicides refulgens (Alexander & DeLaca, 1987). A. colbecki is preyed upon by seastars Notasterias armata, Lophaster gaini, and Odontaster validus, the brittle star Ophiosparte gigas, the proboscis worm Parborlasia corrugatus, the Antarctic whelk Neobuccinum eatoni, and the fish Trematomus bernacchii (Dearborn et al., 1996; Ansell et al., 1998; Vacchi et al., 2000).
