Sushi. What fish are they actually serving you?
When I started as a sushi chef 18 years ago, the types of fish I would see coming into the restaurant were what you expect on a sushi menu: tuna, salmon, Japanese yellowtail, freshwater eel, and white fish. I am using the general label, "white fish" because even then, with less than 10 varieties of fish on the menu many of the white fish I saw was commonly mislabeled. This year I will have served over 100 different species of fish, many of them whitefish.
Whitefish or Shiromi, is the general term for any fish with white flesh. This can be flounder (Hirame), sea bass (Suzuki), sea bream (Tai), etc... But even with these names, the fish were only generally categorized. Japanese sushi chefs would only consider true striped bass to be Suzuki. But today, many of us, including myself, use a hybrid striped bass. There are five species of flounder I serve and the best way for us to identify them at the restaurant is by their English name. We always try our best to be as accurate with our fish identification.
One of the most egregious act by a sushi chef is one that knowingly markets a fish as another. Surprisingly, this happens more often than you think. I've heard of sushi chefs selling a single fish as FIVE different fish! In this instances, the restaurant sold tilapia, not only as Izumidai, but also as: flounder (Hirame), seabass (Suzuki), sea bream (Madai), and red snapper (Tai).
Other instances of misrepresentation would be with everyone's favorite fish, tuna. Three main species of tuna are used in sushi restaurant: Yellowfin, Bigeye, and Bluefin. Bluefin can be further be identified as three different species: Northern Pacific, Southern Pacific, and Atlantic. This differentiation is important when I comes to sustainability (In another post).
The flavor and fat content of the three different species of tuna vary greatly. The Yellowfin is the most and mild, the Bigeye has medium to high fat content, and the Bluefin has the most flavor and fat content and is coveted for its O-toro, belly cut.
Restaurants will sometimes call Yellowfin Bigeye and charge the inflated price. However, it is difficult to pass off Yellowfin as Bluefin. The flavor and fat contrast is just to great. But, the misrepresentation of tuna is not usually with the red tuna but with the white. There is no true "white" tuna but sushi restaurants will market different fish as SUPER white tuna to intrigue guest into buying a fish they would otherwise pass up.
Escolar is one of these fish. It was banned in Japan in 1977 and also once banned in the United States in the early 90s, Escolar has made its way back onto Sushi menus in America as a popular fatty fish option. But, buyers beware, escolar has a waxy keto ester that is indigestible by humans and eating over 3 oz. of this fish, raw or cooked, can cause digestive problems that will have you running to the restroom. (Escolar Wiki).
For your next sushi dinner, choose a restaurant that is transparent about WHERE their fish come from and WHO they get it from. Ask the waiter detailed questions about the fish. And, of course, ask the chef directly. I am proud of every fish I bring into the restaurant and I will gladly share detail about every fish I serve to you.