After a decade of research, Korea has produced individual glass eels for Japanese eel aquaculture. Although Japan also has this technology, its production of seed is not enough to meet external demand. To aid further development, a series of studies led by Dr Sungchul C. Bai, Pukyong National University, Republic of Korea, has defined optimum nutritional requirements and sustainable feed formulations for the eels. Taken from the Global Aquaculture Advocate, a Global Aquaculture Alliance publication.
After a decade of research, Korea has produced individual glass eels for Japanese eel, Anguilla japonica, aquaculture. Although Japan also has this technology, its production of seed is not enough to meet external demand. Despite dependence upon the wild seed, Japanese eel aquaculture production has been growing significantly and comprises over 27% of Korea’s freshwater aquaculture. To aid further development, a series of studies by the authors defined optimum nutritional requirements and sustainable feed formulations for the eels.
Freshwater aquaculture in Korea is dominated by Japanese eels, Anguilla japonica, followed by carp, Amur catfish, rainbow trout, pond loach and tilapia. Over 27% of Korea’s freshwater aquaculture is supplied by eel production due to historical high demand in domestic as well as overseas markets, especially in Japan.
Due to the limited availability of wild seed and a lack of standardized seed production technology, eel aquaculture is a challenging industry. Despite the lack of a complete package for eel aquafarming, aquaculture production grew from a negligible volume of 100 mt in 1971 to 7,257 mt in 2011 (Figure 1). With success in developing glass eels, a growth phase between larvae and juveniles, eel production is expected to further expand.
In the beginning, eel culture in Korea was limited to the collection of seed from rivers that was grown to produce fingerlings for export to Japan and Taiwan for further rearing. Now, Korea raises Japanese eels not only for fingerlings but also for growout to marketable sizes.
Every year, 10 to 20 mt of 0.2-g wild glass eels are captured and grown to a 200-g market size within a year. However, in 2012, only 2 mt of glass eels were captured domestically, and 7 to 8 mt were imported from different countries. The current market price for glass eels is around U.S. $7 per individual ($35,000/ kg), while market-size eels fetch premium farm gate prices of around $50-70/kg.
Favorable government support and research that includes the growing experiences of farmers have enabled Korea to build a strong foundation for eel aquaculture. Rising production reflects improvements in capturing and transporting glass eels, as well as stocking and feeding for maximum yield.
Government policy to protect freshwater resources in 1997 directed the majority of inland farms to terminate culture, so eel aquaculture subsequently moved to indoor systems. A total of 236 flow-through and recirculating eel farms covering an area of 132 ha has been reported.
Indoor systems for eel farming adopt ongoing improvements in methods and equipment for greater efficiency. Flowthrough systems with concrete bottoms are being replaced by circular polypropylene tanks. Tanks ranging from 30 to 300 m2 in size are employed based upon the life stages of the Japanese eels.
Although Japan has developed complete aquaculture technology for eels, its recent annual production of 150 to 200 individuals is not enough to meet external demand. In Korea, Pukyong National University initiated research on Japanese eels in 2002 and achieved success in fertilizing eggs. In 2006, a majority of the eel research moved to the country’s largest fisheries research entity, the National Fisheries Research and Development Institute (NFRDI). Subsequently, Korea’s government fishery policies targeted hatchery development for Japanese eels.
After a decade of research efforts, Korea has finally produced two individual glass eels for aquaculture. Korea should soon have a complete aquafarming package for eels and begin to play a greater role in global eel production.
2000 – 2012. 5m Publishing