Mollusk remains from archaeological and more recent historical contexts provide good proxies to assess environmental change, as well as human impact, both negatively and positively, as reflected, for example, by resource management practices. Rigorous testing of various hypotheses to explain change or relative stability in mollusk distribution in archaeological assemblages requires an understanding of ecological and biological (life history) characteristics of the represented species, as well as access to ethnographic and ethnoarchaeological data on the interaction between people and mollusks. A growing interest in contemporary indigenous resource management among Pacific Island communities has led some archaeologists to seek evidence for sustainable use of resources in the past, to complement the more widespread research conclusions that depict mollusk resource depression and/or shifts in species composition as consequences of negative human impact. Based on fieldwork in Kiribati, eastern Micronesia, and the application of Optimal Foraging Theory, this paper adds support to recent ethnographic, ethnoarchaeological, and archaeological case studies for the sustainable use of mollusks.