“But what if a tuna eats a shrimp?” you ask. Great question. Tuna are predators. They eat smaller fish, squid, and yes, sometimes crustaceans like shrimp. But eating a shellfish doesn’t make you one. By that logic, if you eat a hot dog, you become a pig. Don’t test that theory at a barbecue.
“What if a tuna is canned next to a can of clams?” Still doesn’t change its DNA. Tuna is tuna is tuna. It’s as shellfish as a banana is a potato. Both are food, but one you peel, and one you fry. (Please don’t fry a banana unless it’s plantain—we’re getting sidetracked.)
1 Week Fishing with the FishLocker - Huge Bluefin Tuna & amazing