Is there really any difference between shrimp and prawns?
Biologically speaking, there is a difference between shrimp and prawns, and it’s mainly about gill structure—a distinguishing feature that is hard for the consumer to spot and is typically lost during processing and cooking. This simple fact may be why the terms are often used interchangeably or can vary depending on factors as random as custom and geography. “Prawn” is a term often used in the southern U.S., for example, while northerners might refer to the same specimen as “shrimp.” In Britain and in many Asian countries, it’s all about size: Small crustaceans are called shrimp; larger ones, prawns. Size is actually not a good indication of a true shrimp or a true prawn, as each comes in a wide range of sizes, depending on the species. Taste won’t provide a clue either: As we found in our shrimp and prawn boil here in the test kitchen, each type can sometimes taste more or less sweet, again depending on the species.
The bottom line: We found no problem substituting one for the other in any recipe. The most important thing is to make sure that the count per pound (which indicates the size) is correct so that the same cooking times will apply.