Why is a herring called a rollmop?

A herring is called a rollmop when it is pickled and rolled around a filling, typically onions, spices, or other ingredients. The term "rollmop" likely comes from the German Word "Rollmops," which translates to "rolled jaws," referring to the way the fish is prepared. This dish is popular in various cuisines and is often served as a snack or appetizer. The pickling process enhances the flavor and preserves the fish.