They are raised on fish farms, from capture to prime eating conditions, but eel spawning is mysterious and at least Wikipedia suggests eel reproduction is not currently reproducable in captivity.
There is a pretty fascinating New Yorker article which summarizes the “Book of Eels”
https://www.newyorker.com/magazine/2020/05/25/where-do-eels-...
There is a pretty fascinating New Yorker article which summarizes the “Book of Eels”
https://www.newyorker.com/magazine/2020/05/25/where-do-eels-...