Skates are cartilaginous fish belonging to the family Rajidae in the superorder Batoidea of rays. Stingrays and skates differ primarily in the way they reproduce. Skates are oviparous, that is they lay eggs. Their fertilized eggs are laid in a protective hard case called a mermaid’s purse.
Various cultures indulge in eating fermented fish, but Korea has apparently one of the smelliest. Skate doesn’t urinate like other fish – it passes its uric acid through its skin. When it is fermented, the uric acid breaks down into a compound which smells exactly like ammonia. Fish rapidly spoils, or goes rotten, unless some method is applied to stop the bacteria that produce the spoilage. Fermentation is a method which attacks the ability of microbials to spoil fish; bacteria usually cease multiplying when the pH drops below 4.5.
In Korea, the fish is placed raw into an earthen clay pot and left at room temperature for a few days. Afterwards the uric acid drenching the skin produces ammonia which prevents the fish from rotting. The ammonia causes good and bad bacteria to grow. The good bacteria eventually kills the bad bacteria.
The Mottled Skate was mainly caught off the coast of Heuksando (흑산도) in South Jeolla Province. The island was attacked frequently during the Goryeo Dynasty (918-1392) by Japanese marauders, so the residents were forced to move out. Those people carried several kinds of fish on their journey and most of them spoiled except for skate. [source], The fishermen from Heuksando packed up their belongings and started out on the 5 day journey from Heuksando to Yeongsanpo (Yongsan Port). They brought a variety of fish with them, but it soon all spoiled minus the skate fish, which was preserved. The fishermen ate the fish and enjoyed the sharp tangy taste of the fermented skate. This delicacy was created completely by accident. The people of South Jeolla then began serving hongeo and it became a popular dish eaten on special occasions and at parties throughout the Goryeo and Joseon Dynasties.
The potential problem
These days, most restaurants use skate from other countries [like Chile] and it is frozen for a year. If hongeo is from Korea, the color is pink. If it’s not, it’s lighter. The International Union for Conservation of Nature (IUCN) has assessed the mottled skate as Vulnerable. Annual catches by South Korea averaged 2,700 tons in 1991–1993 but only 220 tons in 2001–2003, indicating a 90% population decline over a ten-year period. [Wiki]
Landings of skates in Korea, taken by fisheries from adjacent waters, have abruptly declined. In Korea, skates are usually the species Raja pulchra (Jeong 1999). The average annual catch from 1991-1993 was 2,700 metric tonnes, but the catch in 2001-2003 was 220 metric tonnes (data from homepage of MOMAF of Republic of Korea 2004), reflecting a serious decline in the biomass collected [IUNC report].
Apparently, the female skate is preferred to its male counterpart because of taste and size. Female skate is bigger and has a better taste, where as the male skate is smaller. Fishermen prefer not to catch them because their penis is sharp, like a thorn and has been known to cut people. Needless to say, for those that have tried eating the less expensive male skate, they will find that even if they add as many ingredients they can muster, the skate penis is flavorless and seen as a culinary useless thing. So in Korea, I’m not sure how popular the saying is, if a guy is useless and underappreciated, then he could be called a ‘Hongeo Penis’ (홍어 거시기) [source].
Korean food is all about preservation, so even accompanying the food with pork, may have provided Koreans with a way to kill off germs on the pig meat, that may have been dangerous to consume alone. Nowadays, I think it’s more of a way to neutralize the smell and throw in some makgeolli (fermented rice alcohol) to help with that as well. Let’s just say I was trying to suck the sweetness of the pork and the familiar kimchi taste out of the whole thing, just so I could avoid the horrible ammonia taste invading my mouth! The worse part? It is not easy to just swallow, skate is a cartilaginous fish, making it too freaken chewy to chew (>_<).
One of the few on Youtube who didn’t seem to mind: