A good deal of work has gone into this study to sort out the genetics of the Sousa genus http://www.wildlifeextra.com/do/ecco.py/view_item?listid=1&listcatid=1&listitemid=19542&live=0#cr
In a nutshell S.chinesis has been split into 3 species.
S. Chinensis remains off of SE Asia, Hong Kong etc;
S. Sahulensis is a new species off the coast of Australia and New Guinea; and
S. Plumbea in the Indian Ocean from Southern Africa through to somewhere around Laos.
All of which I have seen, though I have yet to see the West African species, Sousa teuszi (the West African species)