ISSF reports 86.4 percent of tuna catches coming from healthy stocks

The International Seafood Sustainability Foundation (ISSF) released its annual “Status of the Stocks” report in July 2022, finding global tuna catches are increasingly coming from healthy stocks.

Since its last "Status of the Stocks" report in March 2022, the percentage of total commercial tuna catch worldwide harvested from stocks at “healthy” levels of abundance has increased from 80.5 percent to 86.4 percent. ISSF reports this increase is mainly due to the recent change in rating for the Eastern Pacific Ocean skipjack stock.

ISSF's “Status of the Stocks” is a twice-yearly report, covering 23 major commercial tuna species worldwide, providing results of the most recent scientific assessments of these stocks and the current management measures adopted by regional fishery management organizations. ISSF covers four albacore fisheries in its report, along with four bigeye fisheries, four bluefin fisheries, five skipjack fisheries, and four yellowfin fisheries.

ISSF assigns color ratings (green, yellow, or orange) to each fishery based on three factors: abundance, exploitation/management (fishing mortality), and environmental impact (bycatch). A color rating of green indicates there are minimal sustainability concerns with the stock, yellow indications sustainability concerns but adequate corrective measures in place, and orange indicates sustainability concerns with no adequate corrective measures in place.

The most-recent report found a restoration in the Eastern Pacific Ocean (EPO) skipjack tuna stock, which represents 6 percent of the global tuna catch, resulting in the restoration of its rating of green. The EPO skipjack tuna stock had been downgraded from green to yellow in ISSF's March 2022 report due to a lack of a recent stock assessment by the Inter-American Tropical Tuna Commission (IATTC), which manages the fishery. 

While 86.4 percent of total commercial tuna catches worldwide were sourced from stocks at “healthy” levels of abundance over the past six months, 9.2 percent came from overfished stocks, and 4.4 percent came from stocks at an intermediate level of abundance, ISSF reported.

Of the 23 stocks surveyed, 65 percent of the global tuna stocks are at healthy levels of abundance (an increase from 61 percent in March 2022), 22 percent are at an intermediate level, and 13 percent are overfished. ISSF reported 74 percent of the stocks are considered well-managed in regard to their fishing mortality rate (an increase from 69.9 percent in March 2022) and 22 percent are experiencing overfishing.

The total catch of all commercial tuna stocks was 4.9 million metric tons (MT) in 2020, 10 percent lower than the total catch in 2019.  The five largest catches by volume were unchanged from the last report: Western Pacific Ocean skipjack, Western Pacific Ocean yellowfin, Indian Ocean skipjack, Indian Ocean yellowfin, and Eastern Pacific Ocean skipjack. Overall, 57 percent of the total catch in 2020 was skipjack tuna, followed by 30 percent from yellowfin, 8 percent for bigeye, and 4 percent of albacore. Bluefin tuna accounted for 1 percent of the total catch.

The report found there to be no changes to tuna-production fishing-gear type since March 2022. ISSF found 66 percent of the global tuna catch is caught via purse-seining, followed by 10 percent longline, 7 percent pole-and-line, 4 percent gillnets, and 13 percent miscellaneous gear.

In a related study, ISSF's recent "Large-Scale Tuna Purse Seine Fishing Fleets" report found a decrease in the number of purse-seine vessels operating worldwide. The report aims to provide an annual best estimate of the number of active purse-seine vessels, as these vessels account for approximately 66 percent of the 5.1-million-MT global tuna catch. The report revealed a 3 percent decrease in the total number of purse-seine vessels, a decrease from 1,855 operating in 2021 to 1,808 in 2022, based on RFMO data. The report found there were 642 vessels defined as large-scale purse-seine vessels targeting tropical tuna species in 2022, with a combined fishing capacity of over 834,000 cubic meters, which is down 5.3 percent from 2021 and decreased from the fishing capacity of 865,000 cubic meters, respectively, in 2021. The decrease could be due to several factors, including changes in fleets of medium-sized vessels no longer on the active list, or vessel delisting from the Western and Central Pacific Fisheries Commission (WCPFC) and in the IATTC, ISSF postulated.

The report also found 16 percent of large-scale vessels are authorized to fish in more than one RFMO. Among the world's RFMOs, the WCPFC has the highest number of large-scale purse-seine vessels registrations at 317. ISSF reported 489 vessels are currently registered on the ISSF ProActive Vessel Register (PVR), which represents 76 percent of the total in operation and 82 percent of the world's total fish-hold volume capacity.

This is the fifth ISSF Status of the Stocks report since March 2020, when the COVID-19 pandemic began. The organization warned some RFMOs have issued exceptions to certain monitoring requirements, such as observer coverage, potentially reducing the accuracy of the reporting completed during the COVID-19 pandemic.

Photo courtesy of Jane Rix/Shutterstock