A Record in the River

Lloyd Dobyns: Hi. Welcome to Colonial Williamsburg: Past & Present on history.org. This is “Behind the Scenes” where you meet the people who work here. That’s my job. I’m Lloyd Dobyns and mostly I ask questions.

The story of Jamestown continues to unfold as archaeology proceeds at the fort site. One of the discoveries was an abandoned well where early colonists dumped oyster shells, which were studied by Juli Harding, the senior marine scientist at at the Virginia Institute of Marine Science. She joins me now to explain how oysters join the narrative of America's first permanent English settlement.

What do you learn from oyster shells?

Juli Harding: There’s all kinds of things we can learn from oyster shells. First of all, oysters are like the estuarine equivalent to trees. They’re bivalve mollusks, they have two shells, and as they grow, the shell grows with them. So all of the environmental conditions that the oyster experiences during its entire life are encapsulated as a permanent record in the shell of the oyster.

So think of them not as shellfish that are good to eat, but think of them as little environmental data recorders. One of the nice things about oysters is that, as adults, they get stuck to the bottom – or they stick themselves to the bottom – so they stay in one place for their entire lives. They sit there and they quietly record the environmental conditions around them. They lay down signatures in their shells like trees make rings.

If you hand me an oyster shell, I can tell you a couple of things. We can take measurements of the oyster, basic measurements: how long is it, how wide is it, how cupped is the shell? The shape of the shell reflects where they lived, and also how they lived in terms of competing with their neighbors for food.

But it also, inside the shell, the chemistry of the shell gives us information about the temperature during the life of the oyster of the water, as well as the salinity of the water. So we can get basic biology as well as chemistry from the simple oyster shell.

Lloyd: Ok, now. That wouldn’t do you any good unless you also studied modern oysters.

Juli: Exactly. One of the nice things about the Jamestown well is it gives us oyster shells from the first decade or so after the Europeans got here. So we have modern collections of oyster shells that we can compare to the oysters from the early 1600s, when the Chesapeake Bay was pretty pristine. That window of time from about 1607 up to the late 1620s, the estuary underwent big changes – particularly the James River estuary.

As the colonists get here and they discover that it’s a nice place to live, and they clear the land, and they plant crops and tobacco becomes the big deal, they harvest beavers, because there’s a fur trade, so there’s lots of changes going on on the land, which reflect on how the estuary signal is picked up.

The other thing that’s going on in 1607 when settlers come, is there’s a big drought. It’s the biggest drought in about 800 years. They had the bad luck to show up in the middle of it. During the drought years, the high-salinity water went up to about the mouth of the Warwick River, but there was still salt in the water up at Jamestown.

So oysters would have expanded from their modern footprint, which is the upper limit in the James River is about Mulberry Point in the modern. During the colonists’ era, there were oysters up around Jamestown. So the drought let the Jamestown settlers harvest those Jamestown-era oysters for food right on their doorstep. But at the same time, that confounded their drinking water and did all sorts of things.

So we have oysters as a barometer of the environment, oysters as a food item. One of the things about the oysters in the well is they had to have been able to be picked, or harvested, by the colonists to be in the well. So most likely, some of the really big ones that were down at the base of the oyster reef would have been really hard to get off. So the ones that are in the well are probably the ones that are at the top of the reef, and that were easy to pick, and that were big enough to be interesting as far as food goes.

Our modern oysters are challenged by a couple of different things: disease, changes in the habitat – mostly sediment coming into the rivers, as well as fishing. So the life expectancy of a modern oyster, we think, is somewhere on the order of three to six years. So instead of a normal oyster population structure where, just for an example, you’ve got some kindergarteners up to 12th graders, we’re pretty much dealing with the 3rd and the 4th graders. Nothing older than that in the modern in most of our oyster populations.

Lloyd: So the reefs, in the colonists’ time, would have been bigger.

Juli: Absolutely. Bigger both in terms of spatial coverage, in terms of the area they occupied, as well as higher in the water column. In fact, there were accounts in the colonists’ records of having to worry about low tide and running aground on oyster reefs coming up the James River. So imagine the James River as a place where you’re out in your boat and you have to stick with the channel. If you look at some of the old maps, maybe a third of the River. So on the right side of your boat, towards the bank, you’ve got an oyster shoal. On the left side of the boat, towards the bank, you’ve got another oyster shoal. You’ve got to stay in the middle to be able to get upriver.

Lloyd: Yeah, oyster shoals are not helpful to wooden-hull boats.

Juli: Absolutely not.

Lloyd: What else about the colonists would oysters tell us?

Juli: One of the nice things about working with the Jamestown archaeologists is that they have artifacts – pottery, nails, pipes, things that have come out of the well – and they’ve organized those artifacts in the order in which they’ve found them. So they have a time sequence going down from the top of the well towards the bottom of the well. They’re trying to reconstruct the history of those artifacts. There’s oyster shells intermingled or dispersed within those layers in the well. So they’re building a timeline, the archaeologists, based on their artifacts that correspond with some of the writings that came from that time period.

One of the other cool things about the 1607 – 1617 or so decade is that everyone writes about what they do – where they go, where they get things. It’s very helpful. So by looking at the oyster shells from this well, we can establish, hopefully, an independent chronology of when the well or when the oyster shells go in the well. So for instance, we should be able to tell the season that the oysters were harvested in. Let’s say for discussion, December of 1612 for one layer. Then sequentially we should be able to move forward in time to when the well was filled.

What we’re hoping to do is be able to compare our chronology off the oyster shells that include the season of harvest, the temperature and salinity conditions that the oysters lived in, and as well as some other information that we can get from chemistry analysis, and match up that chronology with the chronology that the archaeologists have come up with independently. So the two of them, we’re hoping, will interdigitate and inform each other. Combined, we can tell the story of the colony, and how they worked with the estuary and used it as a resource.

Lloyd: The oysters, do oysters now, tell us about kind of what we are today, or where we are today?

Juli: The oysters now, just like their predecessors, record a signal of what’s going on in the environment. Their growth rates are affected by what goes on in the environment, just like their life expectancy is. So they do contain information, again, that we’re trying to use to compare with historic oysters.

One of the things, as a modern oyster biologist, that’s a bit of a challenge. Everybody wants to restore the oyster, which is a good goal. But you have to ask the question, “Restore to what?” So the 1600 oysters, especially from the first half of that decade, give us a baseline of what the original system looked like, both from the oyster standpoint as well as from the entire estuary, because they are a barometer of what went on in the estuary during that time.

So the Jamestown well shells, and oyster shells from other archaeological features in the early 1600s are really, really important from a modern standpoint if you’re trying to put things right again, or at least get a little closer than where we are now.

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