The sign outside proclaims the spot is “famous for clams,” but Flo’s Clam Shack is taking a hiatus from hawking fried steamers. The restaurant has been shelling out the crispy, salty dish for decades.

During the dog days of summer, nothing quite hits the spot like a glistening platter of clams on the half shell. And unlike oysters, the prima donnas of the mollusk kingdom, hard-shelled clams are ...