Sea cucumbers are highly valued as food throughout East Asia, and are considered to have important medicinal properties in traditional Chinese and Korean medicine—indeed, the word for sea cucumber in both Chinese (haishen) and Korean (haesam) literally translates to “sea ginseng.” The most important sea cucumber species in these countries, as well as in Japan and Far Eastern Russia, is Apostichopus japonicus, which lives in the temperate coastal waters of the Northwestern Pacific, usually at depths of 40 meters or less. This species occurs in three distinct color morphs (red, blue or green, and black), each of which is associated with a different habitat. The red morph, known as honghaesam in Korea, lives in rocky and gravelly areas and is highly prized throughout its range. In South Korea, honghaesam is particularly associated with the island of Jeju, while the more abundant blue and black color morphs (cheonghaesam and heukhaesam, respectively) are found in sandy and muddy areas in the coastal waters of the mainland.
Agriculture is difficult on Jeju because of the island’s rocky volcanic soils and rugged landscape, so the sea has always been a critically important source of food for Jeju’s inhabitants. For centuries, female divers known as haenyeo have been primarily responsible for gathering marine resources, including shellfish, seaweed, sea cucumbers, octopus, etc. They work with simple tools and without oxygen tanks, and pass their knowledge down from mother to daughter. The culture of the Jeju haenyeo is included on UNESCO’s list of intangible cultural heritage. Honghaesam was traditionally one of the most valuable items collected by the haenyeo, and was even used as money. In the cuisine of Jeju, sea cucumber can be eaten raw (on its own or in soup or salad) or boiled. It is a good food for nursing mothers and can also be used to strengthen the bones and to treat diabetes, asthma, gastroenteritis, arthritis, burns and skin irritations, and fungal infections.
Today, due to overharvesting, pollution, and habitat degradation, Apostichopus japonicus is classified as endangered by the IUCN. It remains a commercially important species, but much of the harvest comes from aquaculture, particularly in China, and overall harvest has declined significantly in recent decades. On Jeju, the local government has helped initiate some aquaculture activities; mature honghaesam are captured before the spawning season so that the fertilized eggs can be collected and reared in tanks or dispersed back into the sea. This has helped keep local populations of honghaesam from collapsing, but it also masks ongoing problems of pollution and environmental change. At the same time, the number of haenyeo is also decreasing—most of the divers are elderly and there are very few young women interested in becoming divers. This is problematic not only because it threatens the future of an important cultural tradition, but also because the haenyeo have intimate, long-term knowledge of the sea and its resources, making them perhaps the best judges of the health of Jeju’s marine ecosystems. In recent years, they have reported declines in most of the species that they traditionally harvest, including honghaesam.