Herring Caviar - Harius (Spain)

Herrings are small oily fish of the genus Clupea found in the temperate, shallow waters of the North Atlantic and the Baltic Sea.
There are 15 species of herring, the most abundant of which is the Atlantic herring, Clupea harengus. Herrings move in vast schools, coming in spring to the shores of Europe and America, where they are caught, salted and smoked in great quantities.