Japanese eel Anguilla japonica is a facultative catadromous fish and distributes in eastern Asian freshwater and coastal areas. The spawning adults begin ocean migration from September to February and migrate to the western waters of the Mariana Islands. The route and duration of spawning migration departing from each growth habitat are poorly understood. Thus, we tracked the spawning adults caught in four areas (Tokai, Tohoku, Kanto, and the Sea of Japan side) using pop-up archival satellite tags (PSATs).
The survey was conducted from October 2019 to February 2020. We released 24 tagged eels from each coastal area. We received 10 data sets and tracked the eels for up to 59 days. The individuals released from the Tokai region moved for southeast. The individuals released in the Tohoku and the Kanto region went south but did not arrive nearby the Kuroshio Current. No individuals released in the Sea of Japan arrived in the Pacific Ocean.
The present study provided information about the oceanic migration of spawning adults departing from the Sea of Japan side and the Tohoku region, but further long-term tracking is required to reveal the spawning migration of Japanese eel.