In this chapter, we conduct a comprehensive review of dimensional data related to mussel shells retrieved from archaeological shell middens from different coastal localities in southern Tierra del Fuego. In this area, human procurement of shellfish predominantly targeted the naturally abundant intertidal species, blue mussels (Mytilus edulis), during the second half of the Holocene. This bivalve retained its role as the dominant species throughout the entire archaeological sequence, showing non-directional shifts in mean shell size over time. Previous studies interpreted fluctuations in mean valve length as indicative of localized impacts on mussel populations, suggesting a sustainable harvesting strategy by highly mobile groups periodically exploiting alternative coastal areas. However, recent zooarchaeological and palaeodemographic analyses suggest a more intensive use of littoral zones during the Late Holocene along the southern coast of Tierra del Fuego. This prompts new inquiries into the temporal dynamics of shellfish gathering practices, hinting at the possibility that local mussel subpopulations faced variable harvesting intensity as part of an overarching process of subsistence changes over time. Diachronic trends in shell sizes are then examined to initially assess the scope and limitations of metrical information for tracking long-term changes in human predation pressure on mollusks within a general context of sustainable use. Additionally, by considering the ecological and actualistic information of these bivalves, their implications are evaluated in light of the area's occupational history.