Of the 83 families of known polychaetes (Rouse & Pleijel, 2001), only the Tomopteridae, Alciopidae, Lopadorhynchidae, Iospilidae, Typhloscolecidae, and Pontodoridae are exclusively pelagic (Fauchald, 1977; Stop-Bowitz,1981).
A total of eight species of planktonic polychaetes were determined; seven of these belong to the families Tomopteridae, Iospilidae, Lopadorhynchidae, Typhloscolecidae and one undetermined species belongs to the family Alciopidae.
Five phyllodocidacean families (Alciopidae, Lopadorrhynchidae, Pontodoridae, Tomopteridae, and
Typhloscolecidae) and two flabelligerid families (Flotidae and Poeobiidae) are dominated by transparent species (Uschakov, 1972; Glasby et al., 2000).