Gardens of plenty: K’yuu ḴudhlḴ’aat’iija (clam gardens) grow clams four times faster

Photo: Darcy Mathews

Its official; by cultivating clam gardens ancestors grew big harvests which supported and nourished large populations flourishing along the coast.

By building rock-walled terraces, ancestors flattened beach-slopes and expanded the intertidal habitat in places where k’yuu clams grow best. ‘Gardeners’ would further boost productivity by enriching the k’yuu kudhlk’aat’iija with ground shells and pebbles, creating ideal conditions for k’yuu to grow.

To find out for themselves how the gardens worked, researchers recently transplanted over 800 k’yuu k’adjuu little baby clams into six ancestral clam gardens and five non-walled natural beaches. The ancestral clam gardens out-performed the non-walled natural beaches, producing k’aaga k’yuu Butter clam yields four times as high and k’aaga k’yuu Littleneck clam yields twice as high. The k’yuu also grew 1.7 times faster and were more likely to survive than their uncultivated cousins. Researchers suggest that with consistent centuries-long management, clam gardens may have been even more productive.

“Our discovery provides practical insights into sustainable ancient marine management techniques that can inform local food security strategies today,” said Amy Groesbeck, a research assistant at the University of Washington, in an interview with Simon Fraser University. “According to the study, some of today’s shellfish aquaculture practices have been shown to undermine near-shore ecosystem resilience. They alter the community composition of near-shore systems, change sediment characteristics, and facilitate the introduction of invasive species.”

Researchers who contributed to the study include University of Washington resource and environmental manager Amy Groesbeck, SFU ecologist Dr Anne Salomon, SFU archaeologist Dr Dana Lepofsky, and University of Washington biologist Kirsten Rowell.