What you can do to protect yourself
The numbers paint a bleak picture, but there are measures sushi fans can take if they want legitimate (or at least semi-legitimate) fish, according to Olmsted. "The broad-stroke solution is to make your own foods. If you control what you are cooking, you can control what you end up eating." That is good advice, but rolling your own sushi roll isn't exactly efficient.
"For restaurants, you need a healthy degree of skepticism. When I was growing up in New York, sushi was a very rare food -- not on every corner or in supermarkets. You needed to go to a Japanese restaurant. It's not meant to be a food you eat three times a week for lunch, they don't do that in Japan. Eat it better, but less," he said.
Basically, make it a priority to go to high-end sushi restaurants sparingly to ensure quality, rather than going to lower- or mid-range options frequently. But, for those who don't have the money or the willpower, there are some things to look for in your rolls.
"I would definitely not order the tuna roll, first of all. But I do love eel. Eel is a cheap fish, it's probably not fake at most places, and it's obvious what it looks like." And nigiri rolls, or even sashimi, tend to be safer options because you can really see what is inside, and big hunks of fish are harder to mask with fakes. "The chopped-up spicy tuna -- that's crazy, you really have no idea what's in it." He also noted, in counter-intuitive fashion, that the cheaper a fish is, the less likely it is counterfeit. So don't be afraid to slum it, in sushi spots, at least.