Annual tuna production is increasing as the number of large purse seining vessels operating in the Pacific Ocean continues to grow, creating international concern about the future sustainability of tuna stocks across the Pacific region which accounts for about 70% of global tuna output.  

Growing demand for raw tuna in various countries is driving the increase in tuna output as consumption of tuna sashimi and Japanese cuisine gain in popularity around the world; at the same time demand for canned tuna (skipjack) is rising more quickly as part of a general trend to healthier eating. 

According to the Western and Central Pacific Fisheries Commission (WCPFC), an estimated 305 purse seiners are fishing in the western and central Pacific Ocean this year, which is 10 vessels more than the 295 purse seiners that operated in the region last year and 10% more than the 287 purse seiners operating in 2012. 

Growth 
As a result of about 80 additional large purse seiners having started to fish in the western and central Pacific since 2004, the total Pacific purse seining tuna catch has grown substantially during the past decade, reaching 1.90 million metric tons (mt) in 2013, an increase of about one third compared with the 1.39 million mt caught in 2004. 

The growth in purse seining has occurred alongside a reduction in longline tuna fishing. Longline vessels operating in the western and central Pacific have decreased during the past decade, decreasing about 15% to around 2,966 vessels in 2013, according to WCPFC, compared with 3,526 vessels that operating in 2010 and some 30% less than the 4,288 longline vessels that were operating in 2004. 

In terms of tuna species, skipjack tuna fishing has grown the most in the Pacific Ocean during the past decade. The total Pacific skipjack catch rose by 50% to reach 1.49 million mt in 2013, according to WCPFC, up from 1 million mt in 2004. 

Yellowfin tuna production, however, has slowed across the Pacific Ocean during the same time frame, falling to about 270,000 mt in 2013. Last year’s total is a decrease of 31% from the record Pacific Ocean yellowfin catch of 390,000 mt recorded in 2012 and 12.5% below the 316,000 mt landed a decade earlier in 2004.

“Global production of tuna is going up, especially for skipjack tuna. Europe, the United States and developing countries are eating canned tuna as it is a source of reasonably priced protein and does not require a cold store to keep,” commented Daishiro Nayahata, managing director of the Organisation for the Promotion of Responsible Tuna Fisheries (OPRT).

“Fresh and frozen tuna prices in Japan are mostly stable but bluefin tuna prices keep going up and down. Long term prices are down from the bubble economy period that ended in 1990; then the Lehman shock happened in 2008 and now the market is recovering after the 2011 Great East Japan earthquake disaster.”

According to WCPFC, the total tuna catch in Western and Central Pacific Ocean region in 2013 was 2.62 million mt. Although the total catch was down slightly from 2.65 million mt the previous year, the current catch is 16% higher than the 2.21 million mt of tuna caught in the western and central Pacific region in 2004.

Concern 
“Bigeye is an important target species for large scale longliner tuna vessels with super-low temperature freezers that are registered under OPRT as larger size bigeye are caught by these due to the nature of their fishing gear,” Nayahata explained. 

“However, for many years “overfishing” of bigeye has been continuing chiefly because of the increased juvenile bigeye catch by purse seiners using FADs (Fish Aggregating Devices) in the western and central Pacific Ocean, according to stock assessments conducted by WCPFC’s Scientific Committee. OPRT members are seriously concerned about the sustainability of this stock and the future of their fisheries.”

Conservation and Management Measures (CMMs) that WCPFC has adopted relating to the conservation of tropical tuna including bigeye stocks have reduced longliner tuna fleets catch quotas detailed under the CMMs. However, overfishing has still continued, Nayahata observed, with OPRT member longliner fleets suffering the reduced efficiency of their fishing operations as a result.

“For purse seine vessels operating in the tropical region (20N-20S), the CMMs have included regulations such as a four-month prohibition on FAD sets to reduce fishing mortality,” Nayahata said. “However, the continuous increase in the number of purse seine vessels operating in this region has brought about an increased number of FAD sets that has led to increased catching of bigeye. This situation is contrary to the recommendations of the WCPFC Scientific Committee and must be rectified.”

Due to OPRT members’ concern about the depletion of bigeye tuna stocks in the western and central Pacific Ocean, the organisation recently wrote to WCPFC executive director, Professor Glenn Hurry, on 4 July 2014, calling for the effective implementation of CMM 2013-01 conservation proposals that WCPFC adopted in December 2013 to assist in the recovery of bigeye stocks in the western and central Pacific Ocean, in particular.

Current overfishing of bigeye is due mainly to the increased catch of juveniles in FAD sets by purse seine fishing vessels. To reduce the number of bigeye juveniles caught and to increase the overall effectiveness of the bigeye overfishing reduction programme, OPRT members are keen to see WCPFC implement agreed measures to reduce fishing mortality in accordance with recommendations from the Scientific Committee as soon as possible.

In its letter to WCPFC, OPRT noted that implementation of measures aimed at reducing the use of FAD sets by purse seine fishing vessels in 2015 and subsequent years are conditional on progress at WCPFC’s Regular Session this year, and are due to be successfully implemented under the CMM 2013-01 conservation proposals that WCPFC has adopted for the period 2014-2017.

Among provisions of CMM 2013-01 that OPRT members wish to see implemented effectively is development of schemes to jointly reduce the capacity of large scale purse seine vessels in the western and central Pacific to the level that existed at the end of 31 December 2012, and to reduce overfishing.

OPRT members also have urged the WCPFC commission to conduct annual reviews from 2014 as stipulated in the CMM to ensure the provisions of CMM 2013-01 have their intended effect.

In addition, and in regard to small scale longliners, OPRT members have noted that comprehensive monitoring should be carried out and enhanced management methods should be considered.

Established in December 2000, OPRT was formed by the Japanese government and the tuna industry to establish a sustainable global longline tuna fishing industry, to stamp out illegal unregulated and unreported (IUU) longline fishing, and prevent overfishing capacity of large scale longline tuna fisheries targeting major sashimi tuna species including Atlantic bluefin, southern bluefin and bigeye tuna.

Fishing associations and fishing boat registration agencies in 16 countries have registered 989 large scale longline fishing vessels with OPRT as of the end of March 2014, representing more than 90% of the world’s large scale tuna longliners equipped with super-low temperature freezers.

OPRT represents all stakeholders in tuna fisheries producing sashimi grade products, Mr Nayahata noted, including major tuna fishing operators all over the world as well as traders, distributors, and consumers in Japan.

Sashimi 
Besides Pacific bluefin caught by coastal fisheries in Japanese waters, longline caught Atlantic bluefin and southern bluefin are used for the finest sashimi – red meat ‘Akami’ and high fat content meat called ‘Toro’, followed by bigeye tuna, yellowfin and albacore.

In the tropical region (20N-20S) of the western and central Pacific, tuna targeted by large scale purse seine vessels for canning are skipjack and yellowfin, though some purse seine-caught yellowfin is processed and supplied to the sashimi market.

Regarding conservation and management of tuna stocks, Nayahata commented: “The good news is that the catch quota of the southern bluefin is increasing and the status of the eastern Atlantic stock is improving. But the bad news is the expanded activities by small scale longline fishermen and the fact that bigeye stock in the western and central Pacific has been indicated as overfished for the first time by the WCPFC Scientific Committee at its latest meeting in August.

“Small scale longliners are going to the western and central Pacific Ocean – these are not illegal fishermen as they have licenses; they catch mostly bigeye, yellowfin and albacore.

“Some WCPFC member countries, however, have shown a considerable increase in the number of smaller longline vessels operating in the western and central Pacific in the past few years.

“In addition, the number of small scale longline fishing vessels with low temperature freezers operating in the Pacific is increasing and many send their catch to Japan in refrigerated containers.”

Previously the bulk of small scale longline vessels ran their fishing operations supplying ice chilled fresh tuna. More recently many have installed low temperature freezers which are affordable to install nowadays and are suitable for storing sashimi grade tuna.

“We believe these small scale longliner problems should be resolved in the tuna-related regional fishery management frameworks in an adequate and timely manner,” Nayahata said.

Catch reduction
Meanwhile, reducing the large scale purse seine vessels tuna fishing capacity in the western and central Pacific remains an important target for OPRT.

“The status of bigeye in the western and central Pacific Ocean is of serious concern and in time, maybe in every ocean, as it seems the number of FAD sets by purse seiners is above the level that allow the sustainable use of bigeye stocks. Purse seiners are using FADS to capture skipjack but inevitably they catch juvenile bigeye,” Nayahata said.

“We are keen to see a reduction in purse seining fishing capacity; it’s too much and not commensurate with the present level of fish stocks. If the Pacific purse seine fleet size never stops increasing in time they must face some problems.”

Japan is the world’s largest consumer of sashimi tuna with about half of the nation’s tuna intake being in the form of sashimi and sushi.

The government Fisheries Agency estimates that around 300,000-400,000 mt of tuna sashimi is consumed in Japan each year. Other major markets include the United States where an estimated 30,000-50,000 mt of sashimi is consumed each year and South Korea where about 15,000-20,000 mt of tuna sashimi is eaten annually.

Including skipjack, Japan consumed around 702,000 mt of tuna in 2012, according to the Fisheries Agency.

Skipjack was the largest species consumed, accounting for 312,000 mt or 44% of all tuna supplied to Japan in 2012. Bigeye amounted to 142,000 mt or 20% of all tuna supplies to Japan followed by yellowfin tuna 125,000 mt or 17% of tuna supplies.

Albacore accounted for a further 90,000 mt of total tuna supplies to Japan followed by bluefin tuna 21,000 mt and Southern bluefin tuna 12,000 mt.

Japanese tuna fishing vessels caught 481,000 mt or 68% of the total 702,000 mt amount of tuna supplied to Japan in 2012. The remaining 222,000 mt of tuna supplied to the Japanese market in 2012 was imported from over 10 other countries.

Taiwan was an important source in 2012 supplying around 64,000 mt, followed by Indonesia which supplied 37,000 mt. Among other countries South Korea supplied 17,000 mt of tuna while China and the Philippines supplied 13,000 mt each, and Vanuatu 12,000 mt.

Main species
Meanwhile, skipjack is the main species caught by the world’s tuna fishing fleet, accounting for 2.6 million mt or 58% of the global tuna catch in 2011, according to FAO figures.

Yellowfin is the second largest tuna species caught worldwide, amounting to 1.22 million mt or 27% of the total tuna catch in 2012, followed by bigeye totalling 384,000 mt or 8.5% of the world’s total tuna catch.

Indonesia is the world’s largest producer of tuna, producing some 591,000 mt of tuna in 2011, accounting for 13% of total global tuna production amounting to 4.49 million mt that year, according to FAO.

Japan is the world’s second largest tuna producer, catching 463,000 mt of the total global tuna catch in 2011, followed by the Philippines with a tuna catch totalling 332,000 mt.

Other important tuna producer nations include Taiwan with 316,000 mt catch in 2011, followed by Spain with 285,000 mt, Equador with a total 246,000 mt catch, South Korea with 244,000 mt and the United States with 227,000 mt.of tuna.

According to FAO, Papua New Guinea’s tuna catch was 165,000 mt in 2011, while Mexico caught 116,000 mt, China 116,000 mt, Sri Lanka 105,000 mt and the Maldives 93,000 mt.