Source: Wild, some farmed
Mercury Risk: Unknown
Lamentably, it’s not easy to find shimaaji in the United States. The sweet delicate flesh of the white trevally, usually labeled on menus as “striped jack,” is often described as a cross between aji and hamachi—a truly succulent combination. If you haven’t tried it, it’s something to experience. But to try it, first you have to find it. And in North American sushi bars, that’s not easy.
There are those who say that everything happens for a reason. If that’s the case, then one might wonder: Why is it so hard for those of us in the United States to get our hands on shimaaji? Well, how’s this for a theory—we can’t get it because if we did, we would eat it, we would like it, and we would want more. And that just might be a problem.
The challenge with white trevally is that it is an unknown. When it comes to delicious but endangered fish like the bluefin tuna, we have solid reasons to cut back. I can cite bycatch (unintended species and juveniles that are caught and discarded), mercury, population crashes, and ecosystem effects as legitimate bases to give bluefin a miss. But shimaaji? I can’t make much of an argument because compared to many other fish, we know virtually nothing about it.
White trevally occurs throughout much of the world in temperate, subtropical, and tropical zones between the low-tide mark and the edge of the continental shelf. It’s caught incidentally in many of these areas, but the Japanese sushi industry, which consumes vast quantities of shimaaji, only uses fish caught in Japanese waters. So although white trevally is found off the shores of Ireland, Tasmania, North Carolina, and a dozen other places, all the pressure seems to be on the Japanese fishery. Why is that? I don’t know.
The intrinsic characteristics of white trevally include a moderate growth rate, mediocre spawning capabilities, and a potential maximum age of over forty years. This doesn’t sound ideal from an environmental standpoint; then again, there is a pronounced paucity of science and stock assessment data. So how does it all translate to sustainability? I’m not sure.
Deep in the Pacific Ocean about five hundred miles south of Tokyo there is a small island known as Chichijima. Some sources say that on this tiny island, fish farmers collect the eggs of white trevally and raise the fish in captivity to meet the consumer demand. Is white trevally farmed in such a manner a better option than the wild product? I have no idea.
There is, however, one thing that I am certain of: Shimaaji is delicious. It is regarded as a luxury fish in Japan, and only a tiny fraction of the catch is exported. And however dangerous it may be for a fish to mature late, or to grow at a snail’s pace, or to reproduce in small numbers—nothing is quite as dangerous as tasting good. So be careful with shimaaji. If you have a chance, give it a try, but think twice before heading back for more.