it is possible Proscoloplos cygnochaetus is in part distributed by shipping as suggested by Meyer et al (2008) as it has been found in Roscoff, France, although also possibly that West wind drift accounts for the distribution around the southern ocean. Meyer et al (2008) state "The enormous geographic range of this species comprises the temperate waters of the whole southern hemisphere and includes the French population. We discuss a dispersal enabled through the effective anchorage on vessels using mucous glands and chaetae possibly combined with architomic reproduction." The authors do not appear to mention rafting as a possible distribution mechanism in the Southern Hemisphere. This would explain occurrences on isolated islands not on main shipping routes.
Meyer, Achim; Bleidorn, Christoph; Rouse, Greg W.; Hausen, Harald. (2008). Morphological and molecular data suggest a cosmopolitan distribution of the polychaete Proscoloplos cygnochaetus Day, 1954 (Annelida, Orbiniidae). <em>Marine Biology.</em> 153(5): 879-889.available online athttps://link.springer.com/article/10.1007%2Fs00227-007-0860-4 Available for editors [request]