It seems that a LOT of cultures around the world have some kind of rotten fish item in their cuisine. Many of the tribes in Canada and Alaska have a food item that is either fermented fish or a sauce made from it. In various Scandinavian cultures one finds several fermented fish items. The same goes for Asia where many cultures have either a fish sauce or fermented fish dish. It seems to be a good way to add sodium and some flavor to you diet.
Wow. Them Roman traders really got around!