Here's how it works: the chef of this fine restaurant orders his fish on Thursday for delivery Friday morning. He's ordering a pretty good amount of it, too, as he's not getting another delivery until Monday morning. All right, some seafood purveyors make Saturday deliveries, but the market is closed Friday night. It's the same fish from Thursday! The chef is hoping to sell the bulk of that fish -- your tuna -- on Friday and Saturday nights, when he assumes it will be busy. He's assuming also that if he has a little left on Sunday, he can unload the rest of it then, as seafood salad for brunch, or as a special. Monday? It's merchandizing night, when whatever is left over from the weekend is used up, and hopefully sold for money. Terrible, you say? Why doesn't he throw the leftover tuna out? The guy can get deliveries on Monday, right? Sure, he can .�.�. but what is preventing his seafood purveyor from thinking exactly the same way? The seafood vendor is emptying out his refrigerator, too! But the Fulton Street fish market is open on Monday morning, you say!! He can get fresh! I've been to the Fulton Street market at three o'clock on Monday morning, friends, and believe me, it does not inspire confidence. Chances are good that that tuna you're thinking of ordering on Monday night has been kicking around in the restaurant's reach-ins, already cut and held with the mise-en-place on line, commingling with the chicken and the salmon and the lamb chops for four days, the reach-in doors swinging open every few seconds as the line cooks plunge their fists in, blindly feeling around for what they need. These are not optimum refrigeration conditions.
This is why you don't see a lot of codfish or other perishable items as a Sunday or Monday night special -- they're not sturdy enough. The chef knows. He anticipates the likelihood that he might still have some fish lying around on Monday morning -- and he'd like to get money for it without poisoning his customers.