In 2004, scientists studying historical overfishing published a study showing how, starting around the 19th century, oyster stocks suffered a “moving wave of exploitation” that traveled down the Atlantic and Pacific coasts of North America and the eastern coast of Australia. The capitalist commercial fisheries that arrived with European colonization and settlement, Rick says, undid thousands of years of sustainable prosperity. “Within 50 years, 100 years, maybe even less in some areas, they’ve depleted that stock.”
But to Rick, that modern narrative of rampant decline is only part of the story. By focusing on the past few centuries, that paper — and many other important scientific studies and conversations — overlook the ways in which major Indigenous oyster fisheries managed to sustain mass productivity for millennia. Paying these fisheries more attention, says Rick, could have far-reaching implications for restoring and managing the flagging oyster populations left today.
To fill in the rest of the story, Rick assembled a diverse, multidisciplinary team of researchers to revisit the history of oyster fishing in the same places as in the 2004 study, but they started their clock in the 1800s and looked backward.
Relying on archaeological and ethnohistorical records, the team followed how changes in the natural world — such as the thawing of glaciers more than 11,000 years ago and the stabilization of sea levels thousands of years later — created an abundance of estuaries and an explosion of intensive oyster harvesting by Indigenous communities for 5,000 to 10,000 years. Through this and other insights, the team is redrawing the historical ecological baseline for these oyster stocks.
The work adds to scientists’ growing understanding of the diversity and value of Indigenous approaches to marine stewardship. Like the oyster gardens, similar systems show up again and again around the world, from Native Hawaiian loko i‘a (fishponds) and Haida Gwaii naw náaGalang (octopus houses) to the shi hu (stone fish traps) of Taiwan and corrales de pesca (fish traps) of Patagonia. These and other examples are being cataloged by a broad collaboration, known as the Pacific Sea Garden Collective, that is working to map this diversity of Indigenous sea gardening innovations across the Pacific Ocean.
In her own work studying historical Indigenous clam gardens on the North American west coast, which date back at least 3,500 years, Anne Salomon, an applied marine ecologist at Simon Fraser University in British Columbia, has noted some of the key techniques that led to these bountiful yet restrained returns. People would till the sediment, replenish shells in the water, and construct low intertidal rock terraces that flatten the shoreline and expand the farmable area. In parts of British Columbia, clam gardens were packed across nearly all available coastal real estate, she says. “Those would have been hubs of major production, but each clam garden itself is relatively small.”
These Indigenous sea gardens doubled or even quadrupled the production of clams, Salomon’s research shows. They also attracted seaweeds, crabs, sea cucumbers and more.