I don’t eat oysters or clams — they look like what I cough-up in the morning — so I don’t even worry about it. Now, shrimp, lobster and crab; that’s another story.
Shrimp, lobster, and crab? Those are all just big bugs that live in the ocean. (I’ll eat plenty of any of them, by the way. Especially Dungeness crab.)
Those are bugs.