On the other hand, people like me who really love fish understand that fish that is frozen at sea almost immediately after being caught is highly desirable.

In fact, the very best “sushi-grade" fish at the most expensive Japanese and other seafood restaurants will always have been frozen at sea.

For one thing, freezing is the only way to rid even the most prime tuna of worms that cause illness in humans if the fish is eaten raw or undercooked.

Even people who don’t care for raw fish often prefer their tuna and other meaty fish a bit medium rare on the inside. You cannot eat that safely unless the fish has been frozen first.

For another thing, large fish like tuna that are caught far out to sea would never make it back to market without being frozen first.

My supermarket carries tuna that has been frozen, and it is excellent. I actually wish they would not buy it and put it in display cases as if it were fresh. For a long time, I figured that was a marketing gimmick.

But then I asked the fish-counter manager about it, and he explained that he receives the frozen tuna in large pieces that he could never sell individually. He has to thaw them so he can cut them into reasonable portion sizes. Since re-freezing would likely turn the flesh mushy, he doesn’t do that.

Lots of fish is sold like this at supermarkets as well at high-end fish markets, and it’s perfectly good and desirable.