Revealing long-term changes in the marine environment and ecosystems of the Southern Ocean

Large-scale multidisciplinary ecological survey reveals long-term changes in the eastern Indian sector of the Southern Ocean

Joint Press Release by Tokyo University of Marine Science and Technology, Hokkaido University, National Institute of Polar Research (NiPR), and Wageningen University & Research.

Summary

• A large-scale multidisciplinary ecosystem survey in the eastern Indian sector (80-150°E) of the Southern Ocean was conducted by the Japanese research vessel, Kaiyo-maru, during the 2018-2019 austral summer (KY1804 survey).
• This was the first time such a large-scale survey was conducted in the area since 1996.
• The biomass estimates of Antarctic krill between this survey and the survey in 1996 were comparable, although there are some caveats in the interpretation.
• The Commission for the Conservation of Marine Living Resources (CCAMLR) regards the estimated biomass of Antarctic krill from this survey as the best available estimate to date.
• Compared to 1996, the southern boundary of the Antarctic Circumpolar Current (SB) in the eastern part of the study area (112–150°E) has shifted 50–120 km southward, and water temperature has increased.
• In the eastern part of the research area, the dominant large zooplankton changed from salps to amphipods, which could be linked to oceanographic changes.
• This first large-scale multidisciplinary ecosystem survey conducted in about 20 years has revealed significant changes in the marine environment and distribution of organisms in this area.
• The findings from this survey are expected to be used for academic research on climate and marine ecosystem changes, and for various purposes by international organizations such as CCAMLR.
• Prof. Hiroto Murase (Department of Ocean Sciences, Tokyo University of Marine Science and Technology; the senior researcher at Japan Fisheries Research and Education Agency at the time of the survey) took the lead in compiling the research results into an online special issue.

The results are compiled in an online special issue of “Progress in Oceanography,” published on March 10, 2025.

The complete press release can be downloaded as a PDF.

Contact

Research contacts

Tokyo University of Marine Science and Technology

 Department of Ocean Sciences

 Associate Professor Hiroto Murase

 Email: hmuras0[a]kaiyodai.ac.jp

Hokkaido University

 Institute of Low Temperature Science

 Professor Shigeru Aoki

 Email: shigeru[at]lowtem.hokudai.ac.jp

 Field Science Center for Northern Biosphere

 Associate Professor Daiki Nomura

 Email: daiki.nomura[at]fish.hokudai.ac.jp

 Graduate School of Fisheries Science

 Assistant Professor Kohei Matsuno

 Email: k.matsuno[at]fish.hokudai.ac.jp

National Institute of Polar Research

 Bioscience Group

 Assistant Professor Nobuo Kokubun

 Email: kokubun[at]nipr.ac.jp

 Center for Antarctic Programs

 Assistant Professor Daisuke Hirano

 Email: hirano.daisuke[at]nipr.ac.jp

Wageningen University & Research

 Wageningen Marine Research

 Dr. Fokje L. Schaafsma

 Email: fokje.schaafsma@wur.nl

Contact for interviews

Tokyo University of Marine Science and Technology

 Public Relations Office

 E-mail: so-koho[at]o.kaiyodai.ac.jp

Hokkaido University

 Public Relations & Communications Division

 Office of Public Relations and Social Collaboration

 E-mail: en-press[at]general.hokudai.ac.jp

National Institute of Polar Research

 Public Relations Section

 E-mail: koho[at]nipr.ac.jp