That's a very interesting link, but saying that we might as well not bother because there's labeling issues is rather overstating the problem. The perfect is the enemy of the good.
>Scientists aiming their gene sequencers at commercial seafood are discovering rampant labeling fraud in supermarket coolers and restaurant tables: cheap fish is often substituted for expensive fillets, and overfished species are passed off as fish whose numbers are plentiful.
The link states that overfished species are being intentionally mis-labelled. I would say that, yes, we might as well not bother if the seafood industry is going to pull these kind of shenanigans, absent some sort of regulation from the government (an unpopular sentiment here).
Surely there must be laws against this already. I have a hard time imagining that claiming that you're selling X when you're in actual fact selling Y is legal. If no one is being prosecuted it must be because the government doesn't care enough, not because they lack laws to prosecute under.