Indigenous people of the west coast of North America used a range of techniques and practices to maintain or increase the production of culturally important foods, including clams. These practices are encompassed within age-old social, economic, and spiritual beliefs and practices of coastal First Peoples. One long-lasting and visible practice was the building of clam gardens.
What is a clam garden?
Clam gardens are ancient intertidal features constructed by the coastal First Nations of British Columbia (Canada) and Native Americans of Washington State and Alaska (USA), to enhance shellfish productivity. These features are made by constructing rock walls at the low tide line along the edges of bays and inlets, transforming naturally sloping beaches or rocky shorelines into productive, level beach terraces. While clam garden morphology, character, and setting can vary greatly, they generally consist of a well-sorted boulder wall built at the lowest tide line and a terrace on the landward side of the wall. By building the walls at particular heights in relationship to the tides (“tidal heights”), these features expand the zone of the beach where clams thrive. According to local knowledge, clamming beaches, including those associated with clam gardens, were kept clear of large rocks as another means to increase clam habitat. The flattened terrace created by garden walls can range in size from a few square meters on small beaches to well over a kilometer in length. These larger beaches are more like vast fields than ‘gardens’ in size.
Where are clam gardens?
There are probably hundreds, if not thousands, of clam gardens that have yet to be recorded along the northwest coast. Rising or dropping sea levels, lack of surveying, and industrial development of the foreshore are among the main reasons why modified beaches are yet to be identified in some regions. Mapping the locations of these features is slow-going. Given that most clam gardens are situated at today’s low-low tide levels, there are only about 40 to 80 daylight hours per year (May – September) when they are visible. Nonetheless, clam gardens have been recorded or observed from Alaska, through British Columbia, and into Washington State.