Of the total tuna catch in 2016, 78% came from stocks judged to be at healthy levels, unchanged since last reported, according to a February 2018 International Seafood Sustainability Foundation (ISSF) Status of the Stocks report. Skipjack tuna stocks, at healthy levels in all ocean regions, constituted more than one-half of the 2016 total catch.

One notable change in stock status in the February 2018 Status report is for Southern bluefin tuna, a stock that has moved from orange to yellow in abundance ratings. Stock abundance is low, about 13% of the unfished level. However, the stock is rebuilding continuously as a result of the implementation of a robust management procedure by the Commission for the Conservation of Southern Bluefin Tuna.

In contrast, the Pacific bluefin stock, along with the Indian Ocean yellowfin stock and the Atlantic Ocean bigeye stock, remains overfished.

There were no dramatic changes in tuna stock status since the previous November 2017 Status report. The updated report reflects new data made available at late 2017 tuna RFMO meetings.

Updated several times per year, Status of the Stocks assigns colour ratings (green, yellow or orange) on stock heath, stock management, and ecosystem impact. The report ranks the 23 stocks of major commercial tunas around the world using a consistent methodology.

In 2016, the total major commercial tuna catch was 4.9 million tonnes, a 2% increase from 2015. More than half of the total catch (57%) was skipjack tuna, followed by yellowfin (30%), bigeye (8%) and albacore (4%). Bluefin tunas (three species) accounted for only 1% of the global catch. These percentages changed only slightly from the Nov. 2017 reporting period.

Globally, 57% of the 23 stocks are at a healthy level of abundance, 13% are overfished, and 30% are at an intermediate level.

Stocks receiving orange scores, indicating overfished status, include Atlantic ocean bigeye, Pacific ocean bluefin and Indian ocean yellowfin.

ISSF reports that 65% of the 23 stocks are experiencing a well-managed fishing mortality rate, and 13% are experiencing overfishing, with no change from the previous report.

The greatest volume (53%) of the world’s tuna is harvested from the Western and Central Pacific, followed by the Indian ocean (20%), Eastern Pacific ocean (13%), and Atlantic ocean (10%).

65% of this is caught by purse seining, followed by longline (12%), pole-and-line (8%), gillnets (3%) and miscellaneous gears (12%). These percentages changed only slightly from the Nov. 2017 reporting period.

Source: ISSF