North Gyeongsang Province has succeeded in the world's first artificial hatching of the giant grouper (dottdom), known as a "legendary deep-sea fish" with annual domestic catches of only about 30 fish.
The Gyeongsangbuk-do Fisheries Resources Research Institute announced Monday that it had secured 2 million fertilized eggs of the giant grouper and artificially hatched 500,000 of them. The institute is currently raising 200,000 juvenile fish measuring 1 centimeter in total length. The achievement comes after 10 years of research since the institute began breeding efforts in 2017.
Since 2017, the institute has secured 28 juvenile giant groupers weighing 50 to 700 grams each and maintained long-term cultivation in onshore tanks. After a decade of management, it secured eight broodfish measuring 1 meter in total length and confirmed the first spawning of two females in May last year. However, the fertilized eggs were in poor condition at the time, resulting in hatching failure. This year, after intensive research on improving egg quality through proper feed supply, nutritional enhancement, and maturation hormone treatment, the institute succeeded in both securing fertilized eggs and hatching them.
The giant grouper is a large species inhabiting deep waters at depths of 400 to 600 meters, growing up to 2 meters in length and 200 to 280 kilograms in weight. Due to the characteristics of deep-sea fish, survival rates are low because of rapid pressure changes during catching, and it takes more than 8 to 10 years for the fish to grow into adults. As a result, there have been few cases of artificial seed production or aquaculture research worldwide.
The research team plans to use the artificially hatched juveniles to conduct basic research on early life history, optimal breeding environments, and prey organisms. Based on this, the institute will establish mass seed production technology and expand the scope to species conservation and fishery resource recovery research. North Gyeongsang Province judges that securing high-value-added deep-sea fish aquaculture technology could become a new growth engine for the East Coast fisheries industry amid declining production of existing species due to climate change.
"The fruit of 10 years of dedication will become a new growth engine for the East Coast fisheries industry," said Yang Kum-hee, Economic Vice Governor of North Gyeongsang Province. "It is highly meaningful that we have restored, with our own technology, fishery resources that are declining due to climate change."
Rumors surrounding the giant grouper have continued due to its rarity. In April, five giant groupers were caught in succession in a single day from a fishing boat that departed from Busan, with the largest specimen being a massive fish measuring 165 centimeters in length and weighing 90 kilograms. The unusual mass appearance led to the spread of speculation online about it being a precursor to a major earthquake in Japan, but experts dismissed such claims as groundless. "A causal relationship between the appearance of deep-sea species and the occurrence of earthquakes has never been confirmed," said Kim Do-gyun, a marine fisheries researcher at the National Institute of Fisheries Science. "It is difficult to interpret this as an earthquake precursor." Instead, analysts suggested that climate change factors such as rising water temperatures may have altered the activity depths of deep-sea species or advanced their spawning periods.
