Furthermore, even its spawning site had not been clearly understood by researchers until recently (it was discovered to be Suruga Bank in 2006), and details of eel ecology are still largely unknown.
また研究者の間でも、近年まで産卵場すら正確には把握されておらず（2006年にスルガ海山と判明）、ウナギの詳しい生態に関してはまだ謎の部分が多い。