The Great Sushi Scam
Smithsonian Magazine reports that mislabeling fish is rampant, particularly in sushi restaurants. Most of that white tuna you're eating is something else. So is the red snapper. And to varying degrees, much of the rest of the fish you're eating is probably some other fish entirely.
The study compiled data from more than 1,200 seafood samples from 674 retailers in 21 states between 2010 to 2012. DNA testing showed that 33 percent of those samples were mislabeled or posing as fish that they were not. Samples claimed to be tuna and snapper had the highest fail rates, at 59 percent and 87 percent, respectively. Only seven of 120 samples of “red snapper” purchased nationwide actually proved to be red snapper. The rest belonged to any of six different misrepresented species.
Two immediate thoughts on this. The first is that this is the sort of thing that even libertarians think that the government is supposed to prevent. Someone in that food supply chain knows that the fish they're selling as tuna is in fact something else entirely. How has this deception become so pervasive?
The second--which is possibly an explanation for the first--is that it's hard to know how much this matters. Before the FDA started cracking down, grocers might stretch your coffee with other kinds of beans, your flour with sawdust. This was not only deceptive, but also dangerous; for example, eating raw, or briefly boiled, beans is not very good for your digestion.
The Smithsonian article suggests that this may also be a problem with the Great Sushi Scam; escolar, the main fish sold as white tuna, can cause "prolonged, uncontrollable oily anal leakage". But in the small servings that you generally eat a sushi restaurant, it's unlikely that such side effects would be common.
When I go to a sushi restaurant, I don't actually care whether the fish I'm getting is tuna; I care whether it is a fish that basically tastes like what I'm used to "tuna" tasting like. And the substitutions generally seem to be pretty good. Moreover, if they weren't--if the fish was disgusting, or wasn't what I was expecting--I probably wouldn't eat there again. So the restaurant owners have the incentive to make their tuna substitutes as good as possible.
But of course, some people do care. Perhaps they are allergic to some fish, but not others. Maybe they can actually distinguish white tuna from escolar. Or possibly they are worried about sustainability, and want to select fish that aren't endangered. This hinders their ability to do that.
(Though with that latter case, I'm not sure what the net environmental cost is. Presumably the substitute fish are more common--i.e., less endangered--versions. So the deception may be helping preserve endangered fish stocks by fooling the environmentally indifferent into eating a more plentiful species).
It's not exactly a victimless crime. I certainly don't condone labelling fraud. But I suspect that the reason the government hasn't cracked down is that the harms are probably pretty low-level and diffuse.