Ancient Clam Gardens: Exploring Cultural and Ecological Mechanisms that Enhanced Clam Production

Summary

Emerging evidence suggests that Northwest Coast First Nations sustained and enhanced shellfish production through features known as clam gardens, intertidal rock-walled terraces, built in the late Holocene. Experiments and surveys have revealed that clam gardens are 2-4 times more productive than non-modified clam beaches, supporting greater densities, biomass, and higher growth rates of important clam species. While heightened productivity within clam gardens is partly attributable to the reduction in beach slope and expansion of the area of optimal clam habitat, traditional knowledge suggests that additional tending practices were used to boost productivity. Practices involved the addition of shell hash to sediments, the aeration of these altered sediments, the reduction of inter and intra-specific competition through the harvest and removal of other filter feeders and the reduction of benthic predators. We simulated the addition of shell hash through a field experiment to determine the extent to which this tending practice further enhances clam productivity, hypothesizing that it improves growth and survival by locally buffering against unfavourable carbonate conditions. Ultimately, the results of this research will inform the degree to which this ancient form of mariculture can be used today to enhance food security and confer resilience to impending oceanic changes.

This Resource is Part of the Following Collections

• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)   •
• Archaeology of Stranded, Intertidal, and Submerged Shorelines on the Northwest Coast of North America

Keywords

Spatial Coverage

Record Identifiers

Abstract Id(s): 17577