Wikipedia
Jogijeot is a variety of jeotgal, a salted fermented dish made with croaker in Korean cuisine. Jeotgal is widely consumed in South Korea. The name consists of the two Korean words, jogi ( 조기 "croaker") and jeot. Jogijeot is widely used in Korean cuisine such as banchan marinated in various sauces, as a condiment, or used as an ingredient in kimchi.
According to the record in Shuowen Jiezi , a dictionary from the Han Dynasty, croaker was harvested in Lelang ( Hangul: 낙랑, Hanja: 樂浪), so it is suggested that Korean people have eaten the fish for a very long time.
Salt weighing 15 to 20% of the croakers is stuffed in and layered over the fish in a jangdok ( 장독, large glazed earthenware jar). The fermentation takes more than one year at 15-20 degrees.