LONDON--(BUSINESS WIRE)--New research from Planet Tracker reveals for the first time the actual catch of the world’s 30 largest tuna harvesters despite their highly opaque disclosures.

The study, Tuna Turner: Investors Must Turn Up Transparency in the Tuna Industry, trawls Global Fishing Watch data to reconstruct catch volumes by species and region for all 2,153 industrial vessels fishing tuna globally. The research attributes these details for the first time to companies and the countries they are headquartered, aiming to fill in the gaps in company disclosure.

The report focuses on the 30 largest harvesters of tuna globally – the ‘Tuna 30*’ – accounting for 46% of global tuna catch. Only four out of 30 firms report any tuna catch volumes, with even lower transparency on species caught, location, catch methods and certification levels: just one of the 30 companies – Bolton Group – discloses this data.

Without knowing what, where, how much and how companies fish, investors cannot know which of them are most exposed to sustainability risks. Whilst most tuna stocks are not overfished, tuna biomass has declined by 40% to 80%. And, major ecological damage persists in numerous tuna fisheries.

The Tuna 30 overall extract 12% of their catch from stocks that are not at healthy levels of abundance or that are experiencing or might experience overfishing. Planet Tracker estimates that over 40% of the harvest from SAPMER, China National Agricultural Development Group and Maruha Nichiro comes from such stocks.

Several tuna species are threatened with extinction. The research finds that Albacora, Maruha Nichiro, Dongwon, Bolton Group and Sajo are likely harvesters of these threatened species.

Planet Tracker also finds that 56% of the Tuna 30’s catch is “dark”, meaning it could not be associated to a company due to missing ownership information or satellite data. Further, most Tuna 30 companies may be spending more time fishing with their Automatic Identification System (AIS) switched off than on.

The study estimates that better data on ownership information and eliminating these AIS gaps could improve profits and valuations in the industry by an average of 0.6% and 1% respectively within five years.

Francois Mosnier, Head of Nature at Planet Tracker, said: “Better transparency, in the form of corporate disclosure on catch and AIS usage, is crucial to help investors understand the exact risks their portfolios are exposed to. We cannot distinguish good behaviour from bad behaviour without first knowing what is actually being caught, where and how on a company-by-company basis.”

Planet Tracker urges investors to demand full disclosure from tuna companies on catch data and AIS compliance as a baseline for responsible investment.

Notes to editor:

*Planet Tracker used Global Fishing Watch data to create a database of 736,000 “likely tuna” fishing events for the year 2022, to analyse 2,153 vessels catching tuna.

Read the full report here https://planet-tracker.org/wp-content/uploads/2025/06/Tuna-Turner.pdf

See interactive dashboard here.

About Planet Tracker

Planet Tracker is an award-winning non-profit financial think tank aligning capital markets with planetary boundaries. Created with the vision of a financial system that is fully aligned with a net-zero, resilient, nature positive, and just economy well before 2050, Planet Tracker generates break-through analytics that reveal both the role of capital markets in the degradation of our ecosystem and show the opportunities of transitioning to a zero-carbon, nature positive economy.