A Preliminary Floristic Survey of the Benthic Marine Algae of Rotuma Island

A preliminary study of the intertidal benthic macroalgal flora of the island of Rotuma (12°30'S 177°05'E; politically attached to the Fiji Island group) has revealed a total of 88 taxa, including 41 Rhodophyceae, 11 Phaeophyceae and 36 Chlorophyceae, representing the first published records of marine algae for this island. Of these, 30 represent new records for the Fijian flora. The Rotuman flora is distinct from that of Fiji, a probable consequence of habitat limitations and high exposure regimes on Rotuman reefs that have led to a predominance of low-profile, robust algal species. A distinct north-south distribution pattern was found, brought about by variations in exposure regimes. Biogeographic considerations further dissociated the Rotuman and Fijian floras, the former being more equatorial and in the path of oceanic currents dispersing algal species from donor areas in the central and western Pacific.