Common lore states that we should only be eating shellfish, especially oysters, in months with the letter "R." So we can help ourselves to all the oysters, mussels, and clams we can eat from September through April, but put the brakes on come May. What about year-round oyster bars? Or fried clam po'boys in the summer?
The "R" rule originally just applied to oysters, but gradually came to encompass all shellfish. There are a few theories about where it came from and what it means for all of us shellfish lovers.
The first and most compelling argument is that Red Tide most often occurs during summer months. This refers to high concentrations of an algae that is toxic to humans. If we eat shellfish that have absorbed this toxin, we can get pretty darn sick. The condition is known as "paralytic shellfish poisoning," or PSP.
However, red tide levels are closely monitored these days and harvesting is banned during those times. Shellfish are also regularly inspected and tested for toxin levels. It's not very likely that any shellfish reaching the market would contain harmful levels of the toxin. Many shellfish, especially oysters and mussels, are also now farmed instead of harvested from the wild, further decreasing the chance of contamination.
The other argument for the "R" rule is that shellfish usually spawn during the summer months. A rest is needed to let the shellfish repopulate. Spawning shellfish also taste different than at other times of the year, and they have a flavor and texture that many people find off-putting.
In our opinion, it's best to talk to your fishmonger or restaurant server whenever buying shellfish that you plan on eating raw. They can tell you whether the shellfish were farmed or from the wild, whether they're spawning, and answer concerns about food safety.
Do you eat shellfish during the summer?
Related: What's the Difference? Little Neck, Cherry Stone, Top Neck, and Quahog Clams
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I live in Maryland and summer is crab season!
Shellfish in the summer is a definite yes here :)
I always thought it was to avoid eating shellfish during the warmer months when, if it has to travel to get to you at all, it would be more likely to spoil (back when transportation was slower and less refrigerated).
I've never heard any of this, and eat shellfish in the summer without issue. Summer is definitely crab time, especially when we hit the jersey shore.
i heard about the spawning season theory firsthand from a friend who ate a spawning oyster.
it was not a good thing.
I don't think crabs and lobsters count--they're crustaceans, not shellfish, right?
In any case, I definitely only eat raw oysters in the R months. Other shellfish (like scallops), I'll eat whenever.
Here's the answer to my own question. From Wikipedia:
"The term shellfish is used both broadly and specifically. In common parlance, as in having "shellfish" for dinner, it can refer to anything from clams and oysters to lobster and shrimp. For regulatory purposes it is often narrowly defined as filter-feeding molluscs such as clams, mussels, and oyster to the exclusion of crustaceans and all else."
The one time I had raw oysters was from a very nice upscale seafood restaurant, and it was in the winter time, and I got the worst food poisoning of my life, so that theory kind of goes out the window, along with my chance of ever trying oysters raw again...
Gussiebuns, it's possible that your body is intolerant of oysters. I ate clams once and thought I had food poisoning, but when I tried them a few months later, I had just as bad a reaction. Turns out, many people, while not allergic, are intolerant of various bivalves (clams, oysters, mussels).
I eat oysters year round but in summer months always carefully check where they're coming from, if from some warmer waters, skip them just to be safe.
Eat 'em up quick before the whole ocean is poisoned with oil.
They're just gross and mushy when they spawn. I'm sure it won't hurt you, but yuck.
I've never had a problem, no matter when I've eaten oysters. Peking duck, on the other hand...
Farm raised mussels can be eaten year round.
I think the rule about not eating oysters in months without an "R" - the summer months - started in the days before refrigeration and refrigerated shipping. Oysters where shipped by rail in wooden barrels filled with ice. During the summer months the ice didn't last very long and the oysters spoiled before they got to their destination.
End of history lesson ;-)