Since Danish fishery biologist Johannes Schmidt’s renowned discovery in the twentieth century, the Sargasso Sea has been widely considered to be the Atlantic Ocean spawning area for the European eel Anguilla anguilla and American eel Anguilla rostrata1. After many research cruises collecting transparent leaf-like eel larvae known as leptocephali, Schmidt proposed a theory that eels in the Atlantic Ocean were born in the Sargasso Sea and then transported by currents to the Caribbean Sea and North American coastal waters in the case of American eels, and to the Mediterranean Sea and European coasts in the case of European eels.