What is the difference between a prawn and shrimp? To a few, this may be as clear as the difference between a lobster and crayfish is to me, but I could not answer the question when my fiance returned from his restaurant job the other night. The question came about after he was inadvertently wrangled into a debate taking place between two patrons: What makes a prawn a prawn and different from a shrimp?
Now, we all like to feel like an expert from time to time, and the difference between a spiny lobster, Maine lobster and crayfish are all very clear to this lobster-loving fanatic. However, is the prawn different because it is from a fresh- versus salt-water environment? Maybe it is the absence of an appendage (as is the differentiation between a claw-less spiny and Maine lobster)? Or, maybe it is sheer size? Most importantly, does it matter? Do you tend to have a preference? Is it based on taste?
Here are the biological facts (and of course there are exceptions not mentioned here). Prawns and shrimp are both decapods and crustaceans, and all that this means is they both have exoskeletons and ten legs. Once cooked and on a plate they are nearly impossible to discern because their main difference is the construction of their gills (or a part usually removed in the preparation and cooking process). They are classified in suborders based on gill structure. The prawn’s is branching (named dendrobranchia), but is lamellar (flat or plate like, pleocyemata) in shrimp. Also, prawns usually have claws on three pairs of their legs, while shrimp only have claws on two; and finally unlike almost all other decapods, prawns do not brood their eggs on the pleopods (legs along their tails) but release the eggs into the water after fertilization.
Now, that clears up all the confusion, right? Well if you are anything like me your level of confusion just went from bad, to worse. Don’t worry, we are not alone for basic research shows this is an often-asked question world wide, however is asked more often by chefs than biologists.
Just ask any chef in Australia and they’ll agree prawns by definition are what American’s refer to as shrimp. Ask the Americans, the larger of the two are shrimp, so does that mean Australians eat large prawns and small shrimp? Or you can ask a biologist and learn that prawns are a lot like lobster in that they can be found in fresh or salt water, so throw that distinction out.
The Food and Agriculture Organization of the United Nations has an answer as clear as day: prawns and shrimp are the same. Above is a page right out off a downloaded file creating a universal vocabulary for prawn and shrimp part distinctions. This came about since shrimp and prawns can be farmed in nations with lax environmental laws, so the UN has influenced legislation governing their farming. Notice the UN doesn’t bother to separate the two but instead recognizes them as one in the same:
Chefs know there is no discernible difference in taste between a shrimp or prawn, but within each of these are varieties that carry different flavors that a fine pallet might be able to notice.
At the end of the day I beg to ask, ‘Who cares?” If a shrimp or prawn is listed on a menu or in the market, I’m more concerned with where they are from (indicating if they are or are not sustainably raised, or even wild), and if they are the right size for my favorite recipe, soy sake shrimp with ginger aioli (pictured above). They are each an excellent, low fat source of protein, Omega fats, and delicious when prepared countless ways.