Wikipedia
Jeotgal
Jeotgal or jeot is a salted fermented food in Korean cuisine. It is made with various seafood, such as shrimp, oysters, shellfish, fish, fish eggs, and fish intestines.
Jeotgal is mainly used as a condiment in pickling kimchi and as a dipping sauce for pig's feet ( jokbal) and blood/noodle sausage ( sundae). Sometimes jeotgal, commonly saeujeot, is added to Korean style stews ( jjigae) and soups ( guk and tang), for flavor instead of using salt or soy sauce (ganjang).
The types of jeotgal vary depending on main ingredients, regions, and family and personal preferences. In past times, due to the limited transportation, regions near seas had more types of jeot compared to the inland areas.