I have seen both in cleaned harvested fish salt and fresh and don't see any advantage to either style.
Each has their applications. Generally when I'm using bait - whether live shad for stripers, big blue runner for amberjack & grouper, chunks for tuna, or fishing up in Alaska with salmon carcasses for halibut - circle hooks are much more effective at reducing the number of gut-hooked fish. I didn't say "eliminate", as there will always be some that swallow the hook. But the vast majority get hooked in the corner of the jaw as intended.
J hooks are far more effective at trolling and other speed uses (cast & retrieve lures). Also very useful for certain bait uses, like shrimp under a popping cork.
Each has its advantages & drawbacks depending on the type of fishing.