Updated ISSF Report Rates State of Tuna Stocks Worldwide
Of the total commercial tuna catch worldwide, 87% came from stocks at “healthy” levels of abundance, according to the newest International Seafood Sustainability Foundation (ISSF) Status of the Stocks report. In addition, 10% of the total tuna catch came from overfished stocks and 3% from stocks at an intermediate level of abundance.
The previous version of this report was published by ISSF in March 2020. This updated report reflects results of tuna RFMO meetings through October 2020, and the next version will include results of RFMO meetings that have taken place more recently or are taking place now.
Several tuna stocks worldwide are considered overfished and/or subject to overfishing:
- The Atlantic Ocean bigeye, Indian Ocean yellowfin and Pacific bluefin tuna stocks are currently overfished and subject to overfishing.
- Indian Ocean albacore and bigeye are subject to overfishing.
- All skipjack and most albacore stocks are healthy.
Ratings for the following species have changed since last reported in March:
- The abundance rating for Eastern Pacific Ocean bigeye has been downgraded from green to yellow, but the fishing mortality rating of that stock has improved from orange to yellow.
- Both the fishing mortality rate ratio and abundance rating for Eastern Pacific Ocean yellowfin have improved from orange to green. This was primarily due to changes in the stock assessment methodology used.
ISSF publishes its signature Status of the Stocks report twice each year using the most current scientific data on 23 major commercial tuna stocks.
Key Statistics in the Report
- Abundance or “spawning biomass” levels: Globally, 65% of the 23 stocks are at healthy levels of abundance, 13% are overfished and 22% are at an intermediate level.
- Fishing mortality levels: 74% of the 23 stocks are experiencing a well-managed fishing mortality rate, and 22% are experiencing overfishing.
- Total catch: The catch of major commercial tuna stocks was 5.2 million tonnes in 2018, an 8% increase from 2017. 58% was skipjack tuna, followed by yellowfin (29%), bigeye (8%) and albacore (4%). Bluefin tunas accounted for 1% of the global catch.
- Largest tuna catches by stock: The five largest catches in tonnes, unchanged since the previous report, are Western Pacific Ocean skipjack, Western Pacific Ocean yellowfin, Indian Ocean skipjack, Indian Ocean yellowfin and Eastern Pacific Ocean skipjack.
- Tuna production by fishing gear: 65% of the catch is made by purse seining, followed by longline (10%), pole-and-line (8%), gillnets (4%) and miscellaneous gears (13%). These percentages changed minimally since the previous report.
The Status of the Stocks report is reviewed by the ISSF Scientific Advisory Committee, which provides advice on its content. The report does not advocate any particular seafood purchase decisions.
The Pandemic’s Impact on the Status of the Stocks
This is the first update to this report since March 2020, when the COVID-19 pandemic started to impact the work of the RFMOs. In particular, meetings of the scientific committees and commissions have been scheduled on different dates than usual, and this has delayed this update.
Furthermore, readers should be aware that RFMOs issued exemptions to certain monitoring requirements such as observer coverage. As such, the summaries of management measures provided for the stocks, particularly in relation to observer coverage, may not be completely accurate in reflecting the monitoring that is ongoing during this exceptional period.
About the Report
There are 23 stocks of major commercial tuna species worldwide — 6 albacore, 4 bigeye, 4 bluefin, 5 skipjack, and 4 yellowfin stocks. The Status of the Stocks summarizes the results of the most recent scientific assessments of these stocks, as well as the current management measures adopted by the RFMOs. Updated twice per year, Status of the Stocks assigns color ratings (green, yellow or orange) using a consistent methodology based on three factors: Abundance, Exploitation/Management (fishing mortality) and Environmental Impact (bycatch).
ISSF produces two Status of the Stocks reports annually to provide clarity about where we stand — and how much more needs to be done — to ensure the long-term sustainability of tuna stocks. The Status of the Stocks presents a comprehensive analysis of tuna stocks by species, and the Evaluation of the Sustainability of Global Tuna Stocks Relative to Marine Stewardship Council (MSC) Criteria provides scores for the stocks and RFMOs based on MSC assessment criteria. The MSC-certified fisheries list (Appendix 2) in Status of the Stocks complements the Evaluation report. Together, these tools help to define the continuous improvement achieved, as well as the areas and issues that require more attention.
In addition, ISSF maintains a data-visualization tool based on its Status of the Stocks report. The “Interactive Stock Status Tool” is located on the ISSF website and accessible through the Status of the Stocks overview page; users can easily toggle through tuna abundance and exploitation health indicators by catch or stock and filter by location and species as well as be informed about the share of total catch by species/stocks and gear types.