Feeding time at the Gochang eel farm in South Korea.These eels are helping to satisfy insatiable appetite for kitchens northeast Asia, where Japanese and South Koreans devour the vast majority of the global catch.Eels, served fresh or processed, are rich in vitamins, calcium and protein. They are popular, especially in the warmer months, to combat fatigue and boost stamina.The species preferred by Asian diners is Anguilla japonica - the Japanese eel.The eel’s larvae migrate from the Philippines Sea to rivers around China, Japan, and South Korea, where the species is overfished.The owner of a chain of gourmet eel restaurants in Japan, Hiroshi Suzuki, said no substitute is as appetizing.“The European or French varieties have too much fat so they repel the special seasoning sauce Japanese expect on freshwater eel.And the North American eels do not have enough fat so they turn out to be too crispy,” said Suzuki.Aquaculture cannot replicate the life cycle of eels, which only spawn once in their lifetimes.That is a challenge for aqua-farmers, such as Lee Jae-jung, a former nuclear power plant engineer,who has been wrestling with slippery eels for nearly 30 years and now processes 190,000 of them every year.“Eels cannot be hatched artificially. Nearly all eels that are farmed come from the sea. These eels are hatched in the Philippines.