Northern shifts in the migration of Japanese glass eels to subarctic Hokkaido Island over the past three decades

7 Jan., 2025

JAMSTEC
Atmosphere and Ocean Research Institute, The University of Tokyo
Graduate School of Agricultural and Life Science, The University of Tokyo
The University of Tokyo III/GS II
Hokkaido University

Key Points

• Field observations conducted from April to July 2021 in a river in southern Hokkaido reported in this study, identified for the first time, the potential recruitment period of juvenile glass eels in Hokkaido may have commenced in May and concluded in July.

• The long-term trend of Japanese eel recruitment to Hokkaido was examined using a three-dimensional particle-tracking model based on ocean reanalysis JCOPE2M, which showed increased recruitment in northern Japan and decreased recruitment in southern Japan during 2014–2023 compared to 1994–2003, that was attributed to the shift in the Kuroshio.

• Simulated recruitment in northeastern Japan indicated an increase in southeastern Hokkaido and a decrease in the Tsugaru Strait, which was linked to the northward shifts of the Kuroshio/Kuroshio Extension and Oyashio, and strengthening of the Tsugaru Current.

https://www.jamstec.go.jp/e/about/press_release/20250107/
(JAMSTEC)