セクションアウトライン

    • Unlike humans, the sex of eels is not determined when they are born.

      The sex of eels is determined only after they have grown to the yellow eel stage (approximately 25–35 cm in length).

    • What is Yellow eel? Click here if you want to know about life stages of Japanese eel URL

    • Strangely, most of the eels captured during the glass eel stage and reared in an eel farm become males.

      However, female is necessary for the seedling production.

      Estradiol-17β is added to the feed for glass eels, promoting the eels to become females.

      (Estradiol is a type of estrogen, which is a female hormone)

       

      Such artificial development of female eels is called “feminization.”