Of the total tuna catch in 2015, 76 percent came from stocks at healthy levels, a decrease of 1 percent from 2014, finds the latest International Seafood Sustainability Foundation (ISSF) “Status of the Stocks” report.
The NGO highlights that the current percentage from healthy stocks figure, while in need of improvement, has stabilized recently following several years of decline: In 2011, 94 percent of the catch came from healthy stocks, followed by 86 percent in 2012, and 87 percent in 2013.
It said there were no dramatic changes in tuna stock status since the previous November 2016 Status report covering 2014 data; the updated report reflects new data made available at late 2016 tuna Regional Fisheries Management Organization (RFMO) meetings.
Skipjack tuna stocks – at healthy levels in all ocean regions – once again constituted more than one-half of the 2015 total catch. Yet RFMO data spurs continuing concern about commercial tuna abundance and/or fishing mortality worldwide, particularly for certain bluefin and bigeye stocks, said ISSF.
Updated several times per year, the report assigns color ratings (green, yellow or orange) on stock heath, stock management, and ecosystem impact.
Indian Ocean yellowfin, Pacific Ocean bluefin, Western and Central Pacific Ocean bigeye, and Atlantic Ocean bigeye score poorly for both abundance and fishing mortality. Most bluefin stocks and one albacore stock are overfished, but combined they are a relatively small fraction of the total catch.
All ocean regions have stocks with mixed scores for abundance and fishing mortality. Inadequate by-catch monitoring and/or by-catch mitigation measures – represented by the Environmental Impact scores – remain a concern in many tuna fisheries studied, most acutely in Mediterranean and Indian Ocean albacore fisheries.
According to ISSF, the total major commercial tuna catch in 2015 was 4.8 million metric tons (MT), a 4 percent decrease from 2014. Fifty-eight percent of this was skipjack tuna, followed by yellowfin (28 percent), bigeye (8 percent) and albacore (4 percent). Bluefin tunas accounted for only 1 percent of the global catch.
Globally, 52 percent of the stocks are at a healthy level of abundance, 31 percent are overfished, and 17 percent are at an intermediate level.
Stocks receiving orange scores, indicating overfishing or overfished status, include Mediterranean albacore, Western Pacific bigeye, Atlantic Ocean bigeye, Pacific Ocean bluefin, Western Atlantic Ocean bluefin, southern hemisphere southern bluefin, and Indian Ocean yellowfin.
Some 64 percent of the catch is made by purse seining, followed by longline (12 percent), pole-and-line (9 percent), gillnets (4 percent) and miscellaneous gears (11 percent).
There are 23 stocks of major commercial tuna species worldwide: six albacore, four bigeye, four bluefin, five skipjack and four yellowfin stocks.
