When is red snapper not red snapper? When a DNA test declares it otherwise.

Species of fish like sheepshead, porgies, and grunts are similar to red snapper but less desirable, and therefore less expensive. Students at the University of North Carolina accidentally discovered these second-class fish while doing DNA analysis on what the package said was red snapper. In addition to their course on recognizing the DNA patterns of certain types of fish, the students received a bonus lesson on mislabeling fish for profit. The local fishmonger had dressed up a grunt to look like snapper, slapped a label on it, and raised the price.

These tricks aren't new. During the years I lived in an ocean-side community, I learned some of the code words for seafood variants. The skate is a bottom feeding fish with human shaped lips, and it looks like a stingray. They are about the size and shape of a garbage can lid. When I hauled in my first one, it was very disquieting until I was able to identify it. Later, I discovered that the meat from the skate's stingray-like "wings" is often sold as scallops, or clamstrips. It tastes fine, but it's not what the customer believes he or she is paying for.

Consumer advocate Tim Duffy described finding some Atlantic cod labeled as a product of China. "I wasn't great in geography," he says, "but I don't think the Atlantic Ocean goes to China." While some misidentifications could be honest mistakes, there is great financial incentive to make the switch.

When the apostle John reminds us to "test the spirits," it is a reminder not to take things at face value. There are false prophets masquerading as true ones, and greed is often the motivating factor. Just because the label says it, doesn't make it so.