Sold as smelt, this is actually a package of Chilean silversides (Odonesthes regia), which is not in the smelt family, Osmeridae. (Image Credit: Ben Young Landis/CC-BY)
This is not a bag of smelt.
Fish are notoriously insufficiently labeled. And sometimes, they are entirely mislabeled, as we will see in this example.
On my last trip to our local Asian supermarket, I also picked up this package of frozen fish. Smelt is one of my favorite fish to eat — various smelt species are eaten in many countries, often deep-fried or grilled whole, with female fish often full of rich, creamy eggs inside. So I was excited to bring this batch home and have a smelt species to write about.
Although the packaging said “smelt” in three different languages — English, French and Chinese — when I opened the bag, something else fell out.
Odontesthes regia is one of several species referred to as “pejerrey” in Peru. (Image Credit: Ben Young Landis)
The fish in my hand had two dorsal fins — the fins along the fish’s back. Both, however, were supported by thin bones, or rays.
True smelts belong to Family Osmeridae and various other families in Order Osmeriformes. True smelts only have one dorsal fin with rays, while the second dorsal fin, located closer to the tail, looks more like a little fleshy nub. This type of fin is called an adipose fin — you can also find them on salmon, trout and most catfish.
The difference in appearance between between an adipose fin and a regular ray-fin. (Image Credit: Ben Young Landis/CC-BY)
A package of Chilean silversides (Odontesthes regia) showing its country of origin, Peru. (Image Credit: Ben Young Landis/CC-BY)
The dorsal fins were a good clue, and narrowed down the possible families of fishes. Also helpful was the country of origin: wild-caught in Peru.
A round of searches online revealed the fish’s identity: the Chilean or Peruvian silverside (Odontesthes regia), a small fish topping at 5 inches (13 cm) native to the estuaries and coasts of Chile and Peru.
Odonthesthes regia, as pictured in the online commerce website Alibaba.com. (Image Source: http://www.alibaba.com)
Silversides belong to Order Atheriniformes, which also contains the freshwater rainbowfishes popular in the aquarium trade, as well as the odd priapiumfishes, in which the male fish has a sex organ extending from underneath its head.
Less bizarre but no less interesting a relative is the California grunion (Leuresthes tenuis), famous for its spawning orgies onto sandy beaches at night. The California grunion is a close relative of our Peruvian silversides, both belonging to the silverside family Atherinopsidae.
In Peru, the Peruvian silverside is referred to as pejerrey, a name also used elsewhere in South America for other silverside species. Pejerrey is “highly appreciated in South America, especially in Peru and Chile where it is considered a fish of excellent gastronomic quality” (Orellana and Toledo 2007). Online recipes show photos of pejerrey sandwiches, and as my Peruvian colleague from graduate school Martin Romero Wolf tells me, “We eat it deep fried or in ceviche. It good and cheap. Has a sort of strong taste.”
Odontesthes regia featured on a Peruvian postage stamp. (Image Source: www. stampsperu.com)
Odontesthes regia, the Chilean or Peruvian silverside. (image Credit: Ben Young Landis/CC-BY)
So pejerrey is what we will call it, to reflect its Peruvian heritage. Now for the fun of it, let’s check on the other names on the the package label.
Eperlan, the French word used, is the name for the European smelt (Osmerus eperlanus) of northern European lakes and seas — a true smelt.
香魚, the Chinese characters used, refers to yet another species on yet another continent, specifically the sweetfish (Plecoglossus altivelis) of East Asian rivers and seas. It is known as ayu in Japan — and it is also a true smelt.
One label. Three names. Three species. Three continents.
But what’s the difference, really? All are small, silvery fish what roam the seas and estuaries, and if you wanted to sell pejerrey to audiences unfamiliar with names like “pejerrey” or “silversides”, you might choose to grab another name that the local audience has context of.
Yet here lies the inevitable disappointment. Those who know the difference will be disappointed. There are indeed differences among the three fish — pejerrey, éperlan, ayu — and having had both ayu and pejerrey, I can say that they differ greatly in their flavors and tastes. Not to speak of their ecologies and cultural contexts.
So I choose not to be oblivious to mislabeled fish. If these days we can make a big fuss about the difference between kale varieties or grape varietals, I think the better thing to do is to better know a fish — and appreciate their splendid biological and gastronomical diversity.
Fried pejerrey served on tortillas. (Image Credit: Ben Young Landis/CC-BY)
Odonteshes regia (Humboldt, 1821)
Pejerrey (click for names in other languages)
Class Actinopterygii (Ray-finned Fishes)
Order Atheriniformes (Silversides)
Family Atherinopsidae (Neotropical Silversides)
FishBase Page: http://fishbase.org/summary/8172
Citations
— Ben Young Landis
Better Know a Fish! 
Thanks for the info. I just purchased a similarly mislabeled bag of “smelt” at my local Asian store. The smaller bags were labeled “smelt,” but the larger bags were labeled “silver smelt,” wild caught, Peru. I tried searching for ‘silver smelt’ when I got home, which is how I eventually came across your post. Mine are definitely the Pejerrey. Question is: what is the mercury level of these little fishies? Haven’t been able to find out…
Glad the info helped! As for mercury, that might take a little digging around research literature. But in general, smaller forage fish have lower amounts of bioaccumulated contaminants, because they have a shorter life-span (less time to accumulate contaminants), and they eat lower on the food chain (they eat less contaminated foodstuffs). This is why most mercury precautions apply to large predatory fish, because they eat high amounts of smaller forage fish over a longer lifetime, and the small amounts of contaminants in all that prey add up and become accumulated in their bodies in higher amounts.
Hi can anybody advise me what i can feed pejerrey that I keep in an aquaponic system
@Leonard. For years I worked on salmon cages in southern Chile and caught and ate tons of Pejerey. While feeding the salmon I noticed that the Pejerrey would swim near the cages and feed on the feed dust that floated on the surface of the water. You might want to purchase some trout feed, grind it up into a find powder and float in on the surface of the the tank water and observe it the fish eats it.
Since this blog is all about accurate naming, I have to mention that “pejerrey” is a local denomination that varies greatly across South America, particularly from one ocean to the other. The Argentinian “pejerreyes”, also members of the Odontesthes family, are much bigger and are eaten grilled or lightly fried, as a main course, and would never be used as bait or to replace smelt: there are no less than four variants (O. Argentinensis, O.Platensis, O.Smitti and O.Nigricans) and can reach up to 24 inches and 3 pounds. There is another smaller variant (O.Incisa), locally known as “Cornalito”, which indeed is used as bait or fried whole, pretty much as smelt.
Ernesto, thank you for the clarification and the local insights! You have provided a perfect example of the many ways we humans encounter biodiversity. (And very cool to learn about other large species.)
Your pictures do not look like the Pejerrey I see in Lima. The ones I eat are stubbier, more broad and flat (less meaty). Great fried and cruchy in a sandwich. 🙂
Thank you. I just mistakenly bought a bag of the Peruvian smelts, but I hope I have enough time to find Atlantic smelts before Christmas. How irritating that our local seafood store went and changed products on us.