THE FACTS

American Indians are said to have introduced this warning centuries ago to early settlers, and nowadays the saying is applied to the months without an R, namely May through August. But it may be outdated.

Shellfish can be problematic in the summer for several reasons. The first has to do with red tides, vast blooms of algae that collect along coastlines, usually in warm weather. They can spread toxins that are soaked up by oysters, clams and mussels.

Image Credit... Lief Parsons

Studies have linked toxic outbreaks to this phenomenon, but only when people ate locally harvested shellfish. Most shellfish sold in restaurants, supermarkets and urban areas are commercially harvested, and as a result are subject to regulations intended to eliminate such hazards.