Researchers Find Ancient Native Americans Harvested and Managed Oyster Reefs

Researchers found that Native Americans sustainably harvested and managed oyster reefs. Once, oysters were plentiful in the east coast estuaries of North America. Since the arrival of the Europeans, however, pollution, disease, and overharvesting have devastated the populations of this keystone species.

Out of all eastern oyster reefs present in Georgia since the year 1889, a mere 8% currently remain. Archaeologists found how Native Americans practiced the ancient sustainable harvesting of this resource, which maintained their health for millennia before the arrival of the Europeans on the continent. This was the finding of a study published in Science Advances. The study can help current efforts in restoring these habitats and in sustainably harvesting oysters.

Atlantic coastal communities have depended on these estuaries for resources. These include the Creek or Muscogee Nation's ancestors. In these sites, archaeologists uncovered trash heaps containing oyster shells.

University of Georgia archaeologist Victor Thompson conducted a study of how the health of reefs differed farther south in the various stages of human occupation in the area. His research team analyzed over 37,000 shells of eastern oysters from 15 Georgia and South Carolina island sites. Of these, ten dated around 2500 to 1500 BC, while the remaining sites dated from around 950 to 1450, in the Mississippian period. They measured shell size to indicate reef health because stressed oysters are usually smaller than healthy ones.

In some of the sites, size reduction was observed. In most locations, however, the average size increased with time. In addition, the Mississippian oysters were more substantial than the oysters from the other sites. This finding suggests that the harvesting practices of Native Americans encouraged oyster reef health. Their size variation also provided clues regarding human societal structures in those communities. Thompson says the Native Americans likely had very complex political and social rules that probably benefited all elements of the ecosystem.

According to Elizabeth Reitz, a zooarchaeologist from the Georgia Museum of Natural History and the University of Georgia, who was not involved in the new research, they did not harvest young oysters and instead allowed them to mature and reproduce.

She says Native Americans could have also removed the dead oysters to provide living oysters additional room for growth. They may also have discouraged oyster predators like snails. Reitz says that bringing the long history of these people's successful use of coastal resources to the attention of resource managers is very important.

The Nature Conservancy Southeast Marine Conservation Director Mary Conley says findings from studies like this can help resource managers choose sites for oyster reef restoration. Thompson agrees with this, but also says the past must be paired with the status of contemporary ecosystems.

In addition, projects on reef restoration along the coast of the Atlantic must also take into account descendant communities like the Creek (Muscogee) Nation, the contribution of whom always tended to be overlooked. Thompson and his team, along with other archaeologists, consulted them for the study. The new research is a step towards the collaboration of researchers with descendant Native American communities in conservation projects.