The Swedes differentiate between sill - herring caught in the North Sea, south of Kalmar - and strömming - fished in the Baltic north of Kalmar, and slightly smaller. They're both herring, and essentially the same species, but to locals they're as distinct as bratwurst and frankfurter.
The consistency of this jarred stuff, on the other hand, is near perfect for a picnic. Delicate-fleshed, but still toothsome, it's cured without cooking - the scales flash silver, the meat is pink. On dense, dark bread, with slices of Herrgårdsost cheese, it can be delicious. At Syltkrukan, the "jam pot," we had "toasts" of egg and sill with strong cups of coffee. It's was great for a light lunch, but Swedes often like more substance with their strömming.
Lithuanian restaurants to Estonian ferries, Dutch beaches to the streets of Brussels, herring is ubiquitous. In America? It's almost unknown. It's a shame, really, because the little creatures are about the perfect food. Raw, tinned, brined, fried, smoked... there's no real cut, when you look at a herring you see what you're going to eat. And, even if the taste is a little mild, it's also a great compliment to its environmental flavors. What other fish is so easily translatable from one preparation to another?
On a sidewalk corner of Slussen, where Stockholm's traffic, people and water come together at a narrow bridge, Nystekt Strömming dishes up some of Sweden's finest and most elemental street food.