Clam gardens are distributed throughout the Pacific Northwest coast from around Sitka, Alaska into northern Washington State. While Indigenous people have always been aware of the local distribution of these features, western scientists now understand how widespread they are. Our expanded understanding is in part due to the observations made by geomorphologist John Harper and biologist Mary Morris while conducting low-elevation aerial surveys of the coastline during the lowest daylight tides of the year.
Comparison of the relatively sparse distribution of clam gardens and cleared beaches in Hunter Island (central coast, BC, Heiltsuk territory) with the very dense distribution of clam gardens on the northern Quadra Island (southern BC, Laich-kwil-tach, and Northern Coast Salish territory).
Google Earth images, edited by Julia Jackley and Keith Holmes, Hakai Institute
These aerial surveys have been augmented by many more local, on the ground surveys. They show that in some locations, like northern Hunter Island in British Columbia, clam gardens and cleared beaches are relatively sparsely distributed. In some other areas, like northern Quadra Island, every possible bit of coastline has been transformed into a clam garden. This means that over one third of the shoreline has a clam garden on it, amounting to about 11 hectares of clam habitat. Furthermore, over one third of this habitat was newly created clam habitat built on bedrock and rocky slopes. By increasing the productivity of already existing clam beaches and dramatically increasing the area where clams could flourish, clam gardens played an undeniably essential role in the past food systems of coastal Indigenous People.