Human‐Mediated Prehistoric Marine Extinction in the Tropical P acific? Understanding the Presence of H ippopus hippopus (Linn. 1758) in Ancient Shell Middens on the R ove P eninsula, Southwest V iti L evu I sland, F iji

At the L apita‐era (1100‐550 B.C. ) settlements ( B ourewa and Q oqo) along the R ove P eninsula in F iji, valves of the reef‐surface‐dwelling giant clam H ippopus hippopus (long extirpated in F iji) occur in shell midden. Valve size/weight increase with depth, suggesting that human predation contributed to its local disappearance. The timing of this event is constrained by (a) the confinement of H . hippopus remains to the lower part of the midden, (b) their likely association with only the stilt‐platform occupation phase at both B ourewa and Q oqo (approximately 1100‐900 B.C. ), and (c) radiocarbon ages. All these suggest that H . hippopus disappeared from reefs here about 750 B.C. Yet human predation is not considered to be a significant cause of extirpation of H . hippopus in the entire F iji group. More plausible is that (climate‐driven) sea‐level fall (55 cm) during L apita times in F iji (approximately 1100‐550 B.C. ) forced changes to coral‐reef ecology that saw this sensitive species extirpated throughout the F iji archipelago. It is also considered possible that the L apita colonizers introduced bivalve predators or diseases to F iji that spread independently of humans throughout these islands.