Nearly a third of shrimp being sold in the USA is mislabeled, according to a fairly extensive study by Oceana (a conservation group focusing upon marine issues):
The study tested 143 shrimp products from 111 grocery stores and restaurants in cities around the Gulf of Mexico like New Orleans and Houston as well as Portland, Oregon; New York; and Washington.
Among the major findings, the most common species substitution was farmed whiteleg shrimp sold as “wild” or “Gulf” shrimp, and 40% of the shrimp samples were species not known to be sold in the United States (including one banded coral shrimp, which is typically an aquarium pet, in a bag of frozen salad shrimp).
Oceana also found a general lack of information on sourcing, with 30% of samples in grocery stores lacking labeling on a country of origin and 29% lacking labeling on whether the shrimp was farmed or wild.
These aren't particularly encouraging findings; especially the lack of country of origin information. That's because a lot of other countries - notably China and other Asian countries - have some really questionable aquaculture practices, including water contamination and the use of substances banned for consumption in the USA.
Reportedly, most of the seafood consumed in the USA (as much as 80%) is imported.
According to an August import alert by the Food and Drug Administration, 25% of seafood samples of catfish, basa, shrimp, dace and eel from China included drug residue.
Although we enjoy shrimp on occasion, our general seafood choices are mostly limited to wild-caught Alaskan salmon, halibut, and cod. I made that decision years ago, as I do most of our family grocery shopping, and the reason for that at the time was the horrid state of fish-farms. It's my understanding that those have been greatly improved over time, but I still refuse to purchase farmed salmon (which are always the Atlantic salmon) or trout.
Of course, trout isn't actually seafood; being freshwater fish (apart from the sea-run cut-throats, which are incredible when they hit your dry fly on a rainy October afternoon).