If you know someone who wears Nantucket Red pants and has a number of personal preferences when it comes to boat shoes, then you know someone who repeatedly tells everyone to only eat oysters during the months that have an 'r' in them.
Everyone already knew that, and we've all sort of accepted it as fact, but where did it come from? According to the New York Times, red tides occur more frequently during the summer months, which can spread toxins to oysters and other shellfish. Oysters also start spawning when the water temperatures warm up, and that process can change the oyster's appearance and texture.
Anyway, regardless of the reason, it seems like people have been avoiding oysters during the summer months for the past 4,000 years. Scientists analyzed a large shell ring off the coast of St. Catherines Island in Georgia, and determined that some of the island's early-early inhabitants didn't harvest oysters during the summer either.
Nicole Cannarozzi, an environmental archaeology collection manager at the Florida Museum of Natural History, said that she and her team were able to determine when the oysters were eaten because of a small parasite that attaches itself to their shells.
The impressed osteodome, the common name for that particular sea snail, attaches itself to the oyster and starts eating it from the inside out. Their life-cycle lasts around 12 months, so by determining each osteodome's age at its death, the researchers are able to learn when the oyster was taken from the water as well.
Cannarozzi and her associates analyzed the oysters and snails that were found in a massive 230-foot wide shell ring that dates back to the Late Archaic period. Those preserved shells were then compared to their living, present-day counterparts, and they determined that the people who lived on St. Catherines Island at that time tended to collect and eat oysters starting in the late fall, and stopping before the late spring.
"People have been debating the purpose of these shell rings for a very long time," Cannarozzi said. "Were they everyday food waste heaps? Temporary communal feasting sites? Or perhaps a combination? Understanding the seasonality of the rings sheds new light on their function."
The researchers have also suggested that these early inhabitants might not have stuck around on the island during the summer. "The seasonal pattern of oyster harvest [...] is congruent with the hypothesis that human activities at St. Catherines Shell Ring fluctuated seasonally," Cannarozzi wrote. "Local and regional communities may have converged for seasonal gatherings during the spring, winter and fall, while during summer months only a small portion of the population remained at the rings."
They've also speculated that these people avoided oysters during those non-R summer months for a few familiar reasons: because of the taste, because they wanted to avoid potential toxins, or because they knew that the oysters reproduced during those months, and they wanted to give them time to reproduce and replenish their oyster stock.
There's no word whether anyone on that Late Archaic-era island had a pair of boat shoes.