Three millennia of human and sea turtle interactions in Remote Oceania

Sea turtles are one of the largest vertebrates in the shallow water ecosystems of Remote Oceania, occurring in both sea grass pastures and on coral reefs. Their functional roles, however, over ecological and evolutionary times scales are not well known, in part because their numbers have been so drastically reduced. Ethnographic and archaeological data is analysed to assess long-term patterns of human-sea turtle interactions (mainly green and hawksbill) prior to western contact and the magnitude of turtle losses in this region. From the ethnographic data two large-scale patterns emerge, societies where turtle capture and consumption was controlled by chiefs and priests versus those where control over turtle was more flexible and consumption more egalitarian. Broadly the distinction is between societies on high (volcanic and raised coral) islands versus atolls, but the critical variables are the ratio of land to shallow marine environments, combined with the availability of refugia. Archaeological evidence further highlights differences in the rate and magnitude of turtle losses across these two island types, with high islands suffering both large and rapid declines while those on atolls are less marked. These long-term historical patterns help explain the ethnographic endpoints, with areas that experienced greater losses apparently developing more restrictive social controls over time. Finally, if current turtle migration patterns held in the past, with annual movements between western foraging grounds and eastern nesting beaches, then intensive harvesting from 2,800 Before Present in West Polynesia probably affected turtle abundance and coral reef ecology in East Polynesia well before the actual arrival of human settlers, the latter a process that most likely began 1,400 years later.