Clam gardens existed historically along the northern Pacific coast of North America as a reliable and important food source for coastal indigenous people. Daphne Munroe, along with collaborator Kirsten Rowell from the University of Washington, recently joined an archaeology team led by Dana Lepofsky from Simon Fraser University to visit and sample a number of these gardens. Indigenous family groups created these gardens 2000 or more years ago by making a rock wall at the lowest low tide, which helped to stabilize the mudflats and expand clam habitat and productivity.
Gardens were tended over many generations by children and elders who maintained the wall, dug for shellfish and returned shells back to the beaches after harvesting. An important mechanism that may have contributed to the high productivity of these ancient gardens is enhanced natural settlement and recruitment of larval clams through purposeful habitat alteration - the addition of shells to the beach. Located on Quadra Island, British Columbia, these gardens provide a natural setting in which Munroe and Rowell will address questions of importance to shellfish larval settlement and recruitment.
Changing pH in the coastal ocean has recently been identified as a critical bottleneck for survival of shell-forming species like clams that may be sensitive to ocean acidification. A better understanding of the habitat conditions created by ancient gardening practices, particularly the influence of shell addition on sediment surface pH and buffering capacity, and how those habitats improve conditions for growing shellfish, provides a window through which to help insure that contemporary farm practices are not only sustainable, but that they take advantage of ways in which local productivity may be enhanced.
Daphne Munroe is a member of the Institute of Marine and Coastal Sciences and shellfish ecologist at the Haskin Shellfish Research Laboratory at Rutgers University. She earned a BSc in Environmental Science at Simon Fraser University in 2000, and a PhD in Animal Science at the University of British Columbia in 2006. As a JSPS PostDoctoral Fellow, she spent nearly two years in Sapporo, Japan studying intertidal community ecology at Hokkaido University, before returning to North America. After teaching courses in Invertebrate Zoology, Biostatistics and Shellfish Aquaculture at Vancouver Island University in Nanaimo, British Columbia (Canada), Daphne moved to New Jersey to continue her research on shellfish fisheries and aquaculture. Currently, she is an Assistant Professor in Marine and Coastal Sciences at Rutgers. Her research focuses on the ways that we can achieve sustainable management of coastal and marine resources such as fisheries and aquaculture.