Subsistence Shell Fishing in NW Santa Isabel, Solomon Islands: Ethnoarchaeology and the Identification of Two Polymesoda (Solander 1786) Species

Abstract

The large mangrove bivalves of the Polymesoda genus represent a major contributor to Indo-Pacific marine resource economies and are frequently recovered from archaeological deposits in this region. Unfortunately, malacologists have long struggled to accurately distinguish between Polymesoda expansa and Polymesoda erosa—the two most prolific and widely distributed species of the Polymesoda genus. For archaeologists this scientific inaccuracy has likely hindered the correct identification of shell remains (casting possible doubt over reconstructions of prehistoric marine subsistence economies) and has led to taxonomic confusion and inconsistencies within archaeological literature. This paper presents new scientific data on P. erosa and P. expansa obtained through ethnoarchaeological investigations of contemporary shell fishing in northwestern Santa Isabel, Solomon Islands. Through interviews with female shell fishers, size analyses of live subsistence shellfish hauls and participant observation of gathering episodes, new criteria for improving the reliability of identification and interpretation of archaeological shell remains are presented. Other outcomes of this research include new insights into the influence of environmental and habitat conditions on shell morphology, which contribute new ecological information on P. erosa and P. expansa that is broadly useful to malacologists (for better understanding distribution, settlement, and survival of species within the mangrove habitat) and archaeologists (for better understanding the influence of habitat conditions on radiocarbon dating of marine shell remains).