Thursday, March 24, 2005

Shrimp vs. Prawns

Update 8/21/09:

It's embarrassing how much I relied upon Google results when writing this post back in 2005, rather than doing some real research. Even more embarrassing is that it's taken me several years to update the thing, after I found some really good sources in 2006.

There are really two questions going on here--the actual scientific differences and the meaning we non-scientists can attach to the terms when we encounter them in seafood restaurants and stores.

My favorite source to address both of these questions, which I discovered in September 2006, is the 2004 book by Philip B. Mortenson, This Is Not A Weasel: A Close Look at Nature's Most Confusing Terms. You can buy it cheaply through Amazon or perhaps find it at a nearby library. Several things are helpful about Mortenson's approach.

First, he isn't just looking at each animal individually, but instead the entry is actually doing a comparison between the meanings of the two words (and "krill," as well). Second, he's looking at both the scientific and the commercial meanings, while some other published sources are only considering the biological details.

Fond of Mortenson's piece on this as I am, I'll return to it in just a moment. First, though, one print resource that's nice for separate articles on the biology of shrimp and prawns is The International Wildlife Encyclopedia, a 20-volume reference work that was published in 1970, 1980, and 1990.

More recently, there's the online Encyclopedia of Life, created by a number of scientists in 2007. Viewing the creation details in the FAQs, it seems pretty reliable. Since the terms "shrimp" and "prawn" are, in fact, rather vague, searches in the EOL for either term return entries for a number of species. Browse through such search results there at your leisure. Two of likely interest are this entry for Common shrimp and this one for Common prawn.

Comparing Morteson's entry to the EOL, it's apparent that he's got a typo, with "Cragon vulgaris" when he means Crangon vulgaris (a synonym of Crangon crangon, the common shrimp). Despite that, I like the discussion of the commonalities and differences between the various species that each somehow share the label of "shrimp" and the same likewise for "prawn." I like even more that he notes that several species commonly named shrimp of some kind (e.g. white shrimp, Kuruma shrimp) share the same taxonomic family with the common prawn (Penaeidae) rather than that of the common shrimp (Crangonidae). Further, he notes that with such a large variety of shrimp species sold from whatever family and genus, they are often sold simply as "shrimp" with no accompanying designation or, similarly relabeled at market as "prawns," taxonomic designation aside.

So while the original post was weakly sourced and the addition too long delayed of some better sources I later found, I think the point stands that if you're asking the difference between shrimp and prawns, you need to consider whether you mean scientifically or commercially. Scientifically, you want to consider various species in a couple different families. In terms of the actual seafood you're eating, particularly here in America, the name of what you're buying may or may not match up to the taxonomic designation. The marketers' concern is often not the concern of the marine biologists.

Original post from 3/24/05:

It's seemed lately that I'm seeing dishes with prawns appearing on more restaurant menus than in the past. I'm not saying they really are there more than before, just that I've noticed them more. I had been thinking it probably just reflected on my lack of culinary sophistication. For instance, I think I only heard of prawns for the first time in my late teens watching Monty Python's Flying Circus on VHS, and I think I've known since then that they're basically big shrimp. But beyond "pretty much like big shrimp," I really couldn't say what constitutes a prawn, so it'd be good to clarify that.

It turns out, though, that there isn't a lot of clarity to be had on the matter. The problem isn't so much about ignorance on my end as it is about confusion nearly everywhere differentiating between shrimp and prawns. Some scientists are able to make distinctions, but it appears that nobody else pays much attention to them, and it looks like there isn't even consensus there. This info sheet from the Museum Victoria in Melbourne, Australia has some pretty clear definitions and explanation of the difference between them. But unfortunately for those of us in the U.S., a key paragraph begins, "The crustaceans that Australians call prawns..." Just Australians? Well, at least not the Yanks, it suggests, concluding the paper with a paragraph headed, "A shrimp in the USA is a prawn in Australia." Terrific. So, north of the equator, ignore all that.

At this site, based out of St. Louis but with a postal address in Boston [huh?], one Alastair Lyon, Science Information Officer, addresses the issue by dismissing it. He responds to the question, "What is the scientific difference(s) between shrimp and prawn?" by laying out the six classes of Crustacean phylum, noting the group (Decapods) that shrimp and prawns belong to within the class Malaconstracans, and then concludes by discussing the similarities between them! He even says outright "Forget 'shrimp' and 'prawn.'"

On the one hand, he did open with, "What you've actually asked is a big question all about Crustacean taxonomy," and has the Museum Victoria backing him up with, "The classification of the Decapoda is very complex, even to a carcinologist (a scientist who studies Crustacea)," but, still, you've got to love the chutzpah of the misdirection here. Essentially, it's this:
"What's the difference between these?"
"To answer your question....here are the similarities."
Maybe he's got an sensible motive to dodge the question, though. It seems there is no difference, but almost no one wants to admit it. The Food and Agriculture Organization of the United Nations is cited here as framing the difference as: "a shrimp is a saltwater crustacean and a prawn is a freshwater crustacean," even though the very next sentence in the article notes "this glosses over the fact that many prawns are caught in marine waters and many more migrate between freshwater and saltwater habitats." Really enjoyably, though, the same sentence concludes with, "[this] is the most widely agreed upon rule we've got." So...what you're saying is...the most agreed upon rule we've got on the matter is...basically useless?

In fact, that same article observes that "
essentially, there are no rules governing what your supermarket can sell as shrimp and what it can sell as prawns." It also included this sentence, my favorite on the subject: "One [seafood] industry expert we spoke to became so exasperated, he swore that no one on earth knows the difference." So I guess I was as good as an expert already.


Essential Update: At least one person has
contemptuously criticized this post and the sources cited in it. For discussion and response, see here.

16 Comments:

Blogger AngieInEngland said...

Thanks for clarifying an issue that I have wondered about for a while. Or not clarifying it. Or making it clear that the two really are the same, interchangable at least. We just moved from the US to Britain and it seems everything we'd have identified as shrimp is now a prawn.

3:37 PM  
Blogger saffisue said...

Yep, the explaination here was clear as mud. Thanx people

5:37 PM  
Blogger Ryan said...

As a scientist, it would be interesting to know the genetic differences. If humans and chimps are 99% similar at the DNA level, then I would suspect shrimp and prawns to be at least that but not 100%.

6:17 PM  
Blogger sunny said...

Here is you explanation;

Arthropods can be subdivided into several classes, one of which is the Malacostraca.

This class contains about half of the crustaceans. The members of this class have a primitive body plan that can be described as shrimp-like, consisting of of a 5-8-7 body plan. They have a small carapace that encloses the head and the thorax, and have a muscular abdomen for swimming. They also have a thin exoskeleton to maintain a light weight. These general characters are common in all members of the class.

The class can be further divided into the Decapods, which are even still divided into the Duedrobanchates (prawns) and the Carideans (shrimp and snapping shrimp).

The prawns have sequentially overlapping body segments (segment one covers the segment two, segment two covers segment three, etc), chlelate (claw like) first three legs, and have a very basic larval body type.

The shrimps also have overlapping segments, however, in a different pattern ( segment two overlaps segments one and three ), only the first two legs are chelate, and they have a more complex larval form.

I hope this clarifies some of your questions.

5:22 PM  
Blogger Stephanie Conn said...

Forget the legs, segmented tails, etc.. we just want to know the difference when it' s on our plates!

I'm relieved to know there's really no difference. My Irish relatives call the little ones they get at home 'prawns', and were happy to cal the jumbo ones we get in Canada 'shrimp." BUt apparently it's not a question of size...

direct link to that Museum page you mentioned:
http://museumvictoria.com.au/discoverycentre/infosheets/what-is-the-difference-between-prawns-and-shrimp/

9:46 AM  
Blogger Joshatdot said...

I've had the impression that shrimp are smaller (say 24~32 count)and prawns are bigger (24 count or less).

2:33 AM  
Blogger Anand said...

Good article, got the differences.

Thanks,
- Anand.

3:50 AM  
Blogger BriansView said...

You have no write to call americans "yanks." I could see calling an american an yank if your british but you sure as hell didnt fight against us because your country is full of pussies.
a thank you. just so its clear you fucking retard.

12:02 PM  
Blogger sunny said...

^^ Troll.

12:06 PM  
Blogger Steve Ely said...

Yeah, Sunny, that does seem rather troll-like by that BriansView character. Alternatively, he's just weirdly touchy, badly confused (in imagining I'm not American myself), and marginally illiterate.

I'm going to leave it, since it's such a novelty for me to get such comments on a blog that I almost never update, but any future comments with such profanities, I'll certainly delete.

Relatedly, I've been meaning to update this post for years now, since it gets way more traffic than anything else I've ever written anywhere, and there's plainly better information than what I found poking around one idle evening four years ago. Perhaps I'll manage that update now.

12:32 PM  
Blogger Steve Ely said...

Post finally updated.

2:18 PM  
Blogger Daniel said...

I've noticed the talk of the fact that these posts are probably rather old and since there are no dates published this may be years after the fact, but i was reading through and felt inclined to agree with the fact that "BriansView" was a little off base. Speaking as a born and raised American, all I can say is #1: "write" in the form he intended it in American English is spelled "right"...just to clear that up...and that I obviously don't know where everyone is from in these posts, but as I know it in the US, "yank" is a somewhat pejorative term used in the South and Mid-west to describe people from the Northeast and New England and I'll go a bit further and say that this would be the first time I have ever seen anyone get upset about a foreigner using the term, as it only carries weight in the regions where it matters in reference to the Civil War...which had very little to do with anyone but Americans fighting each other...

4:34 AM  
Blogger Steve Ely said...

Just so we're clear, folks, I'm an American, not Australian or British or anything. I was just goofing around when I said Yanks. (I'm also a yankee in the sense of northern vs southern--a Pennsylvanian who's spent much of his adulthood living in SC, GA, and TX.)

7:34 AM  
Blogger Hunter Williams said...

Try this article, with diagram:
http://museumvictoria.com.au/crust/caribiol.html

12:38 AM  
Blogger Richard said...

I'm an American living in Thailand which exports more shrimp to the USA than any other country. (It may be the number one exporter of shrimp to the whole world. They raise shrimp in fresh water farms too.) My native Thai girlfriend says shrimp is pronounced "Koong" (which is the best I can translate phonetically). The same word is used for prawns. But like the USA, in the markets and the restaurants they usually translate small ones as shrimp and larger as prawns. I love the tiger prawns, which have stripes and are huge! So they're all "Koong" to me, but the big ones cost more everyhwere!

4:49 AM  
Blogger Hippo Skipper said...

Shrimp vs Prawn – Some Major Differences
source : http://prawnvsshrimp.com/shrimp-vs-prawn-differences/
Generally, Shrimp are smaller than Prawn, but in some cases prawn can be small and shrimp can be big.
Shrimp have claws only on two pairs of legs. While Prawn have claws on three pairs of their legs.
Shrimp’s legs are shorter than Prawn’s legs.
Prawn belong to the Dendrobranchiata and Shrimp belong to the Pleocyemata suborder of the Crustacean family.
Prawns have lamellar gills while Shrimp have branching gills.
Shrimp’s front pincers are bigger while Prawns have bigger second pincers.
Prawn is semi-transparent, we can see its internal organs through the skin. But Shrimp are usually pigmented.
Prawn lay their eggs while Shrimp carry their eggs during the entire breeding season.
Prawn’s body is segmented. Shrimp’s body is comparatively flatter.
Prawns have claws on three pairs of their legs, while Shrimp have claws on three pairs of their legs.
Shrimp is rich in vitamin D while Prawn is a rich in vitamin E.
Shrimp are most often seen in the United States or Latin Anerican countries. While Prawns are usually common in Asia.
Prawns have a stronger and more aromatic flavor and smell than Shrimp.
Shrimps are typically harvested from salt water and Prawn from fresh water.

2:02 AM  

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