Wednesday, June 16, 2010

Talking with Oysters

Back in March, we excavated buckets and buckets of oyster shell, many large and intact, from around the Swann House foundation. We brought a single bucket back to the lab in order to measure and catalog the shells. By doing this we can extrapolate information about all of the oyster. We first measure the dimensions of the shell to get height/length ratio (on left). This ratio can tell us about the environment the shell grew in. Short, squat oysters have a low ratio and formed on hard packed sand. Tall oysters have a high ratio and grew packed together in soft mud. Then we look for evidence of parasites, such as bore holes from sponges and Polychaete Worms (on right). The type of parasite activity reveals the salinity of the water the shell was in. Finally, we note attachments to the shells, like other oysters or barnacles. All of this information together will help us learn where the oysters around the Swann House came from and what their aquatic environment was like. The shells can also tell us the oysters' age and how intensely the bivalve population was being harvested.
We used Dr. Brett Kent's book, Making Dead Oysters Talk, as a guide and for the images.
Click on the image for a closer look.


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