The Mystery of <i>Choromytilus chorus</i> : Factors Affecting the Apparent Demise of a Culturally Important Mollusk Along Western South America

Choromytilus chorus virtually vanished from most Peruvian archaeological sites about 1000 BC. This species’ disappearance is significant because Choromytilus chorus is one of the most recognizable mollusks in the archaeological remains of coastal Peru because of its large size and rich purple color. In this study we investigate the choro mussel, which was a highly valued food source, a raw material for fishhooks and other fishing gear, and a special ritual item in prehistoric times. We look at inconsistencies in reports of its range, habitat, and ecology to explore reasons for the major shift southward of the species' northern limits at the end of the Initial Period (1000 BC), a significant cultural boundary. We identify biological, ecological, and cultural factors that acted together to bring about the sudden extinction of the choro mussel along much of the Peruvian coast. Paramount among these are human overexploitation and periodic environmental changes related to the El Niño phenomenon.