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Article Publié : 28 January 2026

The Ocean Equity Index : the first tool to assess and strengthen equity in ocean governance

Lecture : 4 min

Sustainable Development Goals (SDGs), the United Nations Agreement on the High Seas (BBNJ) and the Kunming-Montreal Global Biodiversity Framework (GBF) have demonstrated strong commitment by governments and international organisations in recent years to social and environmental equity in ocean-related projects and decisions. However, progress is significantly hampered by a lack of clarity on how to define, measure, and monitor equity. To address this challenge, an Ocean Equity Index (OEI) has recently been developed and published in Nature by CNRS scientists as part of the FRB-Cesab Blue Justice project.

The OEI is the first global tool for measuring, comparing, and promoting equity in ocean-related initiatives, projects, and policies; it transforms an often abstract concept into a measurable and actionable standard. Marine protected areas, development programmes, and even entire economic sectors can be analysed and compared to promote initiatives and decisions that benefit coastal communities and marine ecosystems. It also helps identify gaps in rights recognition, participation, and benefit sharing.

Representation of the twelve criteria of the Ocean Equity Index. © Joachim Claudet

The Ocean Equity Index is described in an article published on January 28 in Nature. Free and easy to use, this assessment tool is designed to be accessible to a wide range of stakeholders: local communities, Indigenous peoples, NGOs, scientists, industries, and governments. Available online via a dedicated website and offline through a calculation and visualisation form included in the publication, it assigns a score (from 0 to 3) to 12 criteria for each initiative analysed; the total score is expressed as a percentage of the maximum possible score.

Access the OEI website

Scientists are calling on governments and international organisations to quickly make use of this tool, as the benefits of ocean industries (aquaculture, maritime transport, offshore energy, etc.) are mostly concentrated in the hands of a few, main players at the expense of local populations and marginalised groups (Indigenous peoples, local communities, women and small-scale fishers) who also suffer the negative consequences of the exploitation of ocean resources.

Examples of Ocean Equity Index ratings for various ocean-related projects and policies. © Joachim Claudet

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Reference

The Ocean Equity Index. Jessica L. Blythe, Joachim Claudet, David Gill, Natalie C. Ban, Graham Epstein, Georgina G. Gurney, Stacy D. Jupiter, Shauna L. Mahajan, Sangeeta Mangubhai, Rachel Turner, Nathan J. Bennett, Stéphanie D’Agata, Phil Franks, Jacqueline Lau, Gabby Ahmadia, Mark Andrachuk, Pavanee Annasawmy, Victor Brun, Emily S. Darling, Antonio Di Franco, Louisa Evans, Natali Lazzari, Josheena Naggea, Veronica Relano, Maria C. Pertuz, Sebastian Villasante & Noelia Zafra-Calvo. Nature, 28 January 2026.

DOI : https://doi.org/10.1038/s41586-025-09976-y

> Access the OEI website

> Read the press release on the CNRS website

Contacts

Press contact

Aurélie Meilhon (CNRS)

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+ 33 1 44 96 43 90

Researcher contact

Joachim Claudet

Mail

FRB contact

Violette Silve

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A flagship programme of the FRB, the CESAB (Centre for the Synthesis and Analysis of Biodiversity) is a research facility with international reach, whose aim is to carry out innovative synthesis and analysis of existing biodiversity datasets. Located in Montpellier, it welcomes numerous researchers from all continents each year.

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The French National Centre for Scientific Research (CNRS) is a public research institution and one of the most recognised and renowned in the world. For more than 80 years, it has met the highest standards of excellence in recruitment and has developed multidisciplinary and interdisciplinary research throughout France, Europe, and internationally. Oriented towards the common good, it contributes to France’s scientific, economic, social, and cultural progress. Above all, the CNRS represents 33,000 women and men and 200 professions. Its 1,000 laboratories—most of them jointly operated with universities, schools, and other research organisations—bring together more than 120,000 people; they advance knowledge by exploring living systems, matter, the Universe, and the functioning of human societies. The close links it forges between its research activities and their transfer to society make it a key player in innovation today. Partnerships with companies form the cornerstone of its valorisation policy. This is notably reflected in more than 200 joint structures with industrial partners and the creation of around one hundred start-ups each year, demonstrating the economic potential of its research work. The CNRS makes research outputs and data accessible; this sharing of knowledge is aimed at a wide range of audiences: scientific communities, the media, decision-makers, economic stakeholders, and the general public.