World catches stagnate at a high level

A lot of people still believe that tuna is just one single species. Hardly anyone knows that there are more than half a dozen “genuine” tuna species which differ in their biological properties and are fished to varying degrees. Not every tuna species is as threatened as bluefin tuna – the stock situation has to be considered separately for every marine region and every individual species.

Every year at the new year auction of the Tsukiji fish market in Tokyo a selected tuna is sold at an extremely high price. This year’s result broke all previous records: A magnificent bluefin tuna (Thunnus thynnus) weighing 269 kilograms was sold to the sushi restaurateur Kiyoshi Kimura for 566,350 EUR. The year before a fish weighing 342 kg had been sold for just 296,790 EUR. Of course, this kind of news excites both the media and consumers. Quite a lot of people see such exorbitant prices as a sure sign of how rare “tuna” has in the meantime become. Many of them believe that all tuna cost that much now and fear that this fish species’ days are nearly over, on the grounds that the thought of such excessive profits will be enough to make any fisherman take even the very last tuna out of the sea.

Random samples are taken before the cans are sealed to check that the fish weight meets the specifications.

But tuna is not a single species. There are at least seven fish species that go under the name of “tuna” and they all differ with regard to certain features and characteristics as well as to catch volume, stock situation and market value. Tuna belongs to the Scombridae family which comprises 49 fish species, classified in 15 genera. Mackerel dominates the global fishery in volume terms but in value terms Katsuwonus (bonito) and Thunnus (genuine tuna) are of considerably greater significance. The most important species of tuna from a commercial standpoint are:
• Yellowfin tuna (Thunnus albacares). The relatively pale meat (light tuna) of this tuna species is the preferred choice for canning. Maximum length is 2 m.
• Albacore (Thunnus alalunga). This fish can reach a length of up to 1.30 m and a weight of 15 kg and is the only tuna from which preserves can be produced with nearly white meat which is seen as a sign of particularly good quality.
• Bigeye tuna (Thunnus obesus). This high-quality tuna is mainly traded fresh as sashimi, or frozen, and rarely used for canning (maximum length 2.36 m, max. weight 197 kg).
• Atlantic bluefin tuna (Thunnus thynnus). The biggest tuna species (fishing record is just under 3 m in length and 679 kg). The dark red meat is only sold fresh or frozen.
• Southern bluefin tuna (Thunnus maccoyii). Of considerable commercial significance. Measures up to 2 m and can weigh up to158 kg. Mainly sold fresh to Japan where the species is popular on the sashimi market. Quality and price depend on fat content.
The sixth Thunnus tuna species, longtail tuna or Northern bluefin tuna (Thunnus tonggol), is of little significance to fisheries and only a few states record catches separately in their statistics. The meat of this tuna species which can grow to a length of 136 cm and a weight of 136 kg is paler than that of yellowfin tuna and its flavour can be compared to albacore. The tuna ”species” with the highest catch volume in international trade is not a “genuine“ tuna, since bonito or skipjack (Katsuwonus pelamis) does not belong to the genus Thunnus. With a maximum length of 1.08 m and maximum weight of 18.9 kg bonito is relatively small and is usually already caught at a length of 45 to 80 cm and a weight of 3 to 7 kg. Its dark-coloured, comparatively inexpensive meat is the preferred choice for the canning industry.


Wide range of fishing methods in the industrial and artisanal fisheries

All tuna species are eagerly targeted by the fishing industry. In the six decades since 1950 the catches of the commercially most important six species yellowfin, albacore, bigeye, Atlantic and Southern bluefin, and skipjack have increased nearly tenfold. According to FAO fishing statistics. 412,394 t were caught worldwide in 1950. In 2009 the total catch amounted to more than 4.385,064 t, of which 71.4% were caught in the Pacific. 19.1% in the Indian Ocean, and 9.5% in the Atlantic including the Mediterranean. Skipjack (2,599,681 t) accounted for more than half of the total catch volume of these six species, followed by yellowfin tuna with 1,092,596 t. Catches of bigeye tuna (404,873 t), albacore (256,479 t), Atlantic bluefin (23,204 t) and Pacific bluefin (21,761 t) were considerably lower but this is at least partially compensated for by the very high market value of bluefin tuna.

There are several methods for catching tuna. Purse seines, longlines or handlines are used in the industrial fishery. Purse seines are mainly used for catching smaller tuna that swim in schools close to the water surface Troll lines or pole and line are used for older fishes that tend to be found at a greater depth. Pole and line fishing gear consists of a two to three metre long pole from which a relatively short line with artificial feathered bait and a barbless hook hangs into the water. When pole and line fishing is used 20 or more fishermen can be found standing at the side of a fishing vessel trying to get a catch. Usually each of them holds a pole but when very large tuna are located two fishermen will sometimes work together with the line hanging between two poles. This fishing method is used worldwide and is one of the classic fishing methods for tuna. In a lot of places it can only be used seasonally, however, when the tuna are to be found locally during their long migration routes. In Japan, for example, the fishing season for albacore and skipjack usually begins at the end of July. The catch is heavily dependent on climatic occurrences and biological rhythms. The fishery requires a lot of manpower and is thus expensive and so is often only worthwhile when demand and prices are high. Industrial fishing fleets that operate a long way from the coast thus have to be very flexible and react quickly to changes in the stock and market situation.

The spectrum of fishing methods within the artisanal fishery is even broader, comprising gill nets, beach seines, fish traps (e.g. mattanza in the Mediterranean region) and regionally even today still harpoons, spears and other archaic gear. The artisanal fishery is one of the reasons why it is so difficult to get accurate statistics for tuna fishing. The fishes are sometimes landed locally in small harbours or simply on the beach and only occasionally registered. This is also true of fishing statistics in the big game fishery. Catching a big tuna is a real trophy and so sportsmen will track them anywhere in the tropics and temperate regions. How many fishes are actually caught in the big game fishery can only be roughly estimated.

Albacore tuna (Thunnus alalunga)

Atlantic bluefin tuna (Thunnus thynnus)

Bigeye tuna (Thunnus obesus)

Skipjack tuna (Katsuwonus pelamis)

Longtail tuna (Thunnus tonggol)

Yellowfin tuna (Thunnus albacares)


FADs – effective but controversial in the tuna fishing industry

The boundaries that divide industrial and artisanal fishing often overlap for there are convergent developments in both sectors. In the artisanal fishery for example there is an unmistakable trend towards more intensive fishing. In China and Taiwan as well as in several other countries small-scale fishermen even occasionally use longlines for tuna fishing. In contrast, in the industrial fishery artisanal methods are being used more strongly with the aim of fulfilling the high quality requirements of the global sushi and sashimi markets. Both fisheries also use FADs (Fish Aggregation Devices) to lure and concentrate the tuna in the wide expanse of the sea. The use of FADs developed from the observation that fishes in the open sea like to swim close to boats or flotsam. This does not only apply to tuna and young fishes of many marine species but also to shark, marlin and dolphinfish. In order to make use of this behaviour within the fishery the fishermen give the fishes artificial floats or FADs. These can vary considerably. In the traditional artisanal fishery often just a few palm fronds are tied together so that they drift on the water’s surface, or old ropes are hung down from plastic containers floating in the water. In the industrial fishery on the other hand FADs can be more sophisticated and sometimes even equipped with GPS and sonar to enable determination of the concentration of the fish schools swimming beneath the FAD.

FADs can be anchored in shallow water or they can drift freely in the sea. Usually they float directly on the surface but they can also be a few metres below the surface so prevent them causing an obstruction to shipping. The first fish usually arrive soon after an FAD has been put into the water. Juveniles often prefer to be right underneath the FAD, larger fishes swim around it in concentric circles whose radius can be anything up to 500 metres.

FADs have in the meantime been in use in the industrial fishery for over 30 years to increase the productivity of the purse seiners. The main target species are skipjack, bigeye and yellowfin tuna. Based on rough estimations, about 1.5 m t or one third of the global tuna catch is currently caught using this fishing method. Environmentalists criticise the method, however, because during purse seining with FADs it is mainly young tuna that are caught and there is a lot of by-catch. FADs do not only attract tuna but also other fishes, among them threatened shark species. The longline fishery is also criticised for using as bait valuable fish species that could themselves be marketed as consumer fish. As “top carnivores”, tuna are among the species at the top of the marine food chains and are demanding with regard to their potential prey. Finding bait of the required quality and quantity is becoming more and more difficult and increasingly expensive. In some regions where tuna is caught in large quantities bait fishes are not only caught in the open sea but also produced for this purpose in aquaculture.

The meat of the different tuna species varies considerably. Yellowfin and albacore is relatively pale, whereas skipjack and bluefin are much darker.

EU recovery plan to strengthen the Atlantic bluefin tuna stock

The biggest problem in the tuna sector, however, is the overfishing of individual stocks. In the case of Atlantic bluefin tuna, overfishing is said to date back to the end of the 1960s. Since then in the opinion of the International Commission for the Conservation of Atlantic Tuna (ICCAT) the stock has diminished by more than 70%. The stock situation of several tuna populations in the East Pacific is apparently also difficult. The bigeye tuna stock is at a low level, the average size of yellowfin tuna in the catch has fallen, and a lot of small fishes get into the nets unintentionally, as pointed out by the Inter-American Tropical Tuna Commission (IATTC) which is responsible for the protection and management of tuna stocks in this region. In the Coral Triangle, the marine region between Indonesia, Malaysia, the Philippines, Papua New Guinea and East Timor, several stocks are showing signs of overfishing.

Most strongly threatened are the bluefin species in the Atlantic and Pacific. There are some hopeful signs at present for the stocks in the Atlantic, due to the fact that after years of waiting the responsible parties at last seem to be taking more decisive action. In 2006 at the ICCAT meeting in Dubrovnik an ambitious recovery plan was concluded that provides for reduced fishing quotas, higher minimum landing sizes and stricter controls and penalties. Two years later this plan was revised at the meeting in Marrakesh and translated into EU law in 2009. This means there are now better chances of ensuring adherence to the fishing quotas allocated by the ICCAT in the East Atlantic and Mediterranean. In June 2010 the EU Commission closed the fishery prematurely to protect the tuna and prevent endangering stock recovery. The fishing quota for the year 2011 was reduced to 12,900 t, compared to 13,500 the previous year. This is not enough for environmentalists, however, who demand a total fishing ban.

And there is more positive news. According to IATTC the Pacific albacore stocks are apparently in a good condition, showing no signs of overfishing. Certification by Friends of the Sea confirms that several tuna fisheries are sustainable. After the Irish albacore troll fishery and the pole and line fisheries of the Azores, Brazil and Senegal, the line fisheries of Sri Lanka and the yellowfin handline fisheries of the Philippines were awarded the sustainability certificate. Just recently fisheries of the eight PNA states (Parties to the Nauru Agreement, i.e. Micronesia, Kiribati, the Marshall Islands, Nauru, Palau, Papua New Guinea, the Solomon Islands and Tuvalu) received the MSC certificate for the purse seine fishery on free skipjack schools. This means that 30 per cent of bonito catches from the PNA fishery and 16% of bonito catches from the western and central Pacific now bear the blue and white MSC seal. Other tuna fisheries are currently undergoing auditing. The problem of overfishing is admittedly not solved by certification but the efforts made within the tuna fisheries show that the concept of sustainability is finding increasing support there.


Worldwide popularity of tuna products

Tuna is traded on the global market both fresh (chilled), frozen (recently super frozen, too) and canned. The export share of fresh tuna rose hugely during the last three decades. In 2008 114,345 t of tuna were exported fresh compared to only 3,513 t in 1978. The export volume in 2008 was actually lower than in the previous years – possibly under the impression of the global financial crisis – for from 2000 to 2007 exports remained fairly stable between 140,000 and 150,000 tonnes. Exports of frozen tuna amounted to just over 600,000 t in 2008. Unfortunately statistics do not say how high the share of super frozen tuna was but the worldwide rise in demand from sushi and sashimi restaurants probably led to a rise of exports in this product segment, too. It is still, however, canned tuna that tops the list of tuna exports. Statistics name an export volume of 1.2 million tonnes for this product category in 2008.

The individual product segments within the marketing landscape have undergone shifts but canned tuna is still the most important product.

The biggest producer and main exporter of canned tuna is Thailand, whose canning industry processes between 700,000 and 800,000 t of raw materials per year. The most important tuna species is skipjack, followed by yellowfin tuna and albacore. Although there are about 20 canneries that process tuna in Thailand most of them are relatively small. The three big players in the industry – next to market leader Thai Union Frozen Products with its subsidiaries Thai Union Manufacturing and Songla Canning, Narong Canning and Chitiwat Manufacturing – together control nearly three quarters of the export sector. They offer all the typical products that are popular in this segment: solid pack, chunks and flakes (shredded) tuna in various broths, marinades, sauces or vegetable oils (sunflower, soy, olive oil), in water or brine. The size of the cans ranges from small units as commonly found on supermarket shelves to large cans for caterers and other bulk users. Over 98% of the canned tuna produced in Thailand goes into export.

Competition is growing elsewhere, however. In the middle of 2011 four new canning factories for tuna went into operation on Papua New Guinea, overtaking the Philippines who had until then been the second largest canned tuna producer after Thailand. In the coming years the four companies are expected to produce up to 1,330 t of products per day. The chance of success for Papua New Guinea is favourable for the country is located next to the world’s major tuna fishing grounds and can export its products duty-free into the EU provided they fulfil all hygiene and IUU requirements. In Spain a lot of Galician canned tuna producers are already worrying about these developments because they are likely to put price pressure on producers.