Traditionalists will be avoiding one of the Lowcountry's signature foods this month because there's no "r" in August (or any summer month, for that matter). Some less traditional oyster lovers may scoff at what seems like another quaint custom, but there's actually some proof that this r-restricted dictum may not only be scientifically valid but quite ancient.
Research conducted by the Florida Museum of Natural History at a 4,000-year-old shell ring on the Georgia coast shows that the native people responsible for these mysterious rings up and down the southeast coast were harvesting oysters during the fall, winter and early spring, but not during the summer. The timetable was determined by studying the remains of parasitic snails attached to oyster shells. The snails have a known life cycle of twelve months, so by measuring the length of the stylus the snails insert into the oyster shell, researchers could extrapolate when the host oyster had been collected and its shell deposited at the ring.
The ancient nomadic hunter/gatherers responsible for shell rings likely moved inland during the summer, the research suggests, partly because experience had taught them that oysters harvested in the summer months were watery and shrunken, although they might not have known the cause - that the oyster's reproductive cycle peaks during the summer and leaves the mature animals weak and emaciated. The harvesting cycle at these shell rings may be the earliest example of sustainable aquaculture, letting oyster populations replenish before returning to them in the autumn.
Written cautions against eating raw oysters during the summer appear in an English cookbook of 1599, when reliable refrigeration methods were far in the future but sickness from consuming the food in the hot months was well-documented. Modern harvesting and icing methods help get around that danger; but, still, many oyster farmers suspend market shipments in the summer until young oysters spawned during the warmer months help re-establish populations.
So is it safe to eat oysters this time of year, or should you be a traditionalist and wait until the fall? It's your choice, but without that "r" in the month, be cautious.