Only eat oysters in months with an 'r'? Rule of thumb is at least 4000 years old
oodie tradition dictates only eating wild oysters in months with the letter “r” – from September to April – to avoid watery shellfish, or worse, a nasty bout of food poisoning. Now, a new study suggests people have been following this practice for at least 4,000 years.
An analysis of a large shell ring off Georgia’s coast revealed that the ancient inhabitants of St. Catherines Island limited their oyster harvest to the non-summer months.
How can scientists know when islanders were collecting oysters? By measuring parasitic snails.
Snails known as impressed odostomes, Boonea impressa, are common parasites of oysters, latching onto a shell and inserting a stylus to slurp the soft insides. Because the snail has a predictable 12-month life cycle, its length at death offers a reliable estimate of when the oyster host died, allowing Florida Museum of Natural History researchers Nicole Cannarozzi and Michal Kowalewski to use it as a tiny seasonal clock for when people collected and ate oysters in the past.
Citation: Cannarozzi NR, Kowalewski M (2019) Seasonal oyster harvesting recorded in a Late Archaic period shell ring. PLoS ONE 14(11): e0224666. https://doi.org/10.1371/journal.pone.0224666