Sardine hailing from the Portuguese port of Albufeira (known as Imperador Sardinha) are globally recognized as being the highest grade on Earth because they are more delicate in texture, & carry more of a pronounced flavor than western Atlantic or California specimens due to the astonishingly high oil content in both the flesh and skin. This "oil" is rich in healthful omega fatty acids and is the source of their flavor (lower fat content in some sardines and herring can actually make the fish taste dry when prepared). Both fish have large, shimmering scales that are loosely attached (and easily removed). However, when it comes to the primary culinary distinction between Sardina pilchardus - the "true" European Sardine & Domestic landings, the Portuguese Emperor Sardine tends to be more plump and meaty offering higher yields
When we think of sardines we most often think of them canned and packed in oil. The name "sardine" itself it is coined after the island of Sardinia in the Mediterranean, where they schooled abundantly and some believe we first canned there.