Tuna

From Wikipedia, the free encyclopedia
  (Redirected from Tunafish)
Jump to: navigation, search
For other uses, see Tuna (disambiguation).
"Tunas" redirects here. For other uses, see Las Tunas.
Tuna
Tuna assortment.png
Tunas (from top): albacore, Atlantic bluefin, skipjack, yellowfin, bigeye
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Scombridae
Subfamily: Scombrinae
Tribe: Thunnini
Starks, 1910
Genera

A tuna is a saltwater finfish that belongs to the tribe Thunnini, a sub-grouping of the mackerel family (Scombridae) – which together with the tunas, also includes the bonitos, mackerels, and Spanish mackerels. Thunnini comprises fifteen species across five genera,[1] the sizes of which vary greatly, ranging from the bullet tuna (max. length: 50 cm (1.6 ft), weight: 1.8 kg (4 lb)) up to the Atlantic bluefin tuna (max. length: 4.6 m (15 ft), weight: 684 kg (1,508 lb)). The bluefin averages 2 m (6.6 ft), and is believed to live for up to 50 years.

Their circulatory and respiratory systems are unique among fish, enabling them to maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish – the yellowfin tuna, for example, is capable of speeds of up to 75 km/h (47 mph).[2] Found in warm seas, it is extensively fished commercially, and is popular as a game fish. As a result of over-fishing, stocks of some tuna species such as the Southern bluefin tuna have been reduced dangerously close to the point of extinction.[3]

This article is
one of a series on
Commercial fish
Blue walleye.jpg
Large pelagic
billfish, bonito
mackerel, salmon
shark, tuna

Forage
anchovy, herring
menhaden, sardine
shad, sprat

Demersal
cod, eel, flatfish
pollock, ray
Mixed
carp, tilapia

Etymology[edit]

The term tuna derives from Thunnus, the Middle Latin form of the Ancient Greek: θύννος (thýnnos) “tunny-fish” – which is in turn derived from θύνω (thynō), "to rush; to dart".[4]

Taxonomy[edit]

The Thunnini tribe is a monophyletic clade comprising fifteen species in five genera:

The cladogram is a tool for visualizing and comparing the evolutionary relationships between taxons, and is read left-to-right as if on a timeline. The following cladogram illustrates the relationship between the tunas and other tribes of the family Scombridae. For example, the cladogram illustrates that the skipjack tunas are more closely related to the true tunas than are the slender tunas (the most primitive of the tunas), and that the next nearest relatives of the tunas are the bonitos of the Sardini tribe.[1]

The Tunas: Thunnini tribe, within the Family Scombridae
family Scombridae 
 subfamily
Gasterochismatinae 


 Butterfly kingfishes (1 genus)





 subfamily
Scombrinae 

tribe Scombrini 

 Mackerels (2 genera)






tribe Scomberomorini 

 Spanish mackerels (3 genera)





tribe Sardini 


 Bonitos (4 genera)






 tribe Thunnini,
 Tunas 

 Allothunnus, slender tunas




 Auxis, frigate tunas




 Euthynnus, little tunas




 Katsuwonus, skipjack tunas



 Thunnus, true tunas 
 subgenus Thunnus

 bluefin group


 subgenus Neothunnus

 yellowfin group















Cladogram: Tunas are classified into the tribe Thunnini (bottom-right in the above diagram) – one of four tribes in the family Scombridae.[1]

True tuna species[edit]

Relative sizes of various tunas, with the Atlantic bluefin tuna (top) at about 8 ft (2.4 m) in this sample

The "true" tunas are those that belong to the genus Thunnus. Until recently, it was thought that there were seven Thunnus species, and that Atlantic bluefin tuna and Pacific bluefin tuna were subspecies of a single species. In 1999, Collette established that based on both molecular and morphological considerations, they are in fact distinct species.[5][6]

The genus Thunnus is further classified into two subgenera: Thunnus (Thunnus) (the bluefin group), and Thunnus (Neothunnus) (the yellowfin group).

Thunnus, the true tunas
Common name Scientific name Maximum
length
Common
length
Maximum
weight
Maximum
age
Trophic
level
Source IUCN status
Thunnus (Thunnus) – the bluefin group
Albacore tuna T. alalunga
(Bonnaterre, 1788)
1.4 m
(4.6 ft)
1.0 m
(3.3 ft)
60.3 kg
(133 lb)
9–13 yrs 4.31 [7][8] NT IUCN 3 1.svg Near threatened[8]
Southern bluefin tuna T. maccoyii
(Castelnau, 1872)
2.45 m
(8.0 ft)
1.6 m
(5.2 ft)
260 kg
(570 lb)
20–40 yrs 3.93 [3][9] CR IUCN 3 1.svg Critically endangered[3]
Bigeye tuna T. obesus
(Lowe, 1839)
2.5 m
(8.2 ft)
1.8 m
(5.9 ft)
210 kg
(460 lb)
5–16 yrs 4.49 [10][11] VU IUCN 3 1.svg Vulnerable[11]
Pacific bluefin tuna T. orientalis
(Temminck & Schlegel, 1844)
3.0 m
(9.8 ft)
2.0 m
(6.6 ft)
450 kg
(990 lb)
15–26 yrs 4.21 [12][13] LC IUCN 3 1.svg Least concern[13]
Atlantic bluefin tuna T. thynnus
(Linnaeus, 1758)
4.6 m
(15 ft)
2.0 m
(6.6 ft)
684 kg
(1,508 lb)
35–50 yrs 4.43 [14][15] EN IUCN 3 1.svg Endangered[15]
Thunnus (Neothunnus) – the yellowfin group
Blackfin tuna T. atlanticus
(Lesson, 1831)
1.1 m
(3.6 ft)
0.7 m
(2.3 ft)
22.4 kg
(49 lb)
4.13 [16] LC IUCN 3 1.svg Least concern[17]
Longtail tuna T. tonggol
(Bleeker, 1851)
1.45 m
(4.8 ft)
0.7 m
(2.3 ft)
35.9 kg
(79 lb)
18 years 4.50 [18][19] DD IUCN 3 1.svg Data deficient[19]
Yellowfin tuna T. albacares
(Bonnaterre, 1788)
2.4 m
(7.9 ft)
1.5 m
(4.9 ft)
200 kg
(440 lb)
5–9 yrs 4.34 [20][21] NT IUCN 3 1.svg Near threatened[21]

Other tuna species[edit]

The Thunnini tribe also includes seven additional species of tuna across four genera. They are:

Other tuna species
Common name Scientific name Maximum
length
Common
length
Maximum
weight
Maximum
age
Trophic
level
Source IUCN status
Slender tuna Allothunnus fallai
(Serventy, 1948)
1.05 m
(3.4 ft)
0.86 m
(2.8 ft)
13.7 kg
(30 lb)
3.74 [22] LC IUCN 3 1.svg Least concern[23]
Bullet tuna Auxis rochei rochei
(Risso, 1810)
0.5 m
(1.6 ft)
0.35 m
(1.1 ft)
1.8 kg
(4.0 lb)
5 years 4.13 [24][25] LC IUCN 3 1.svg Least concern[25]
Frigate tuna Auxis thazard thazard 
(Lacépède, 1800)
0.65 m
(2.1 ft)
0.35 m
(1.1 ft)
1.7 kg
(3.7 lb)
5 years 4.34 [26] LC IUCN 3 1.svg Least concern[27]
Mackerel tuna,
Kawakawa
Euthynnus affinis
(Cantor, 1849)
1.0 m
(3.3 ft)
0.6 m
(2.0 ft)
13.6 kg
(30 lb)
6 years 4.50 [28][29] LC IUCN 3 1.svg Least concern[29]
Little tunny E. alletteratus
(Rafinesque, 1810)
1.2 m
(3.9 ft)
0.8 m
(2.6 ft)
16.5 kg
(36 lb)
10 years 4.13 [30] LC IUCN 3 1.svg Least concern[31]
Black skipjack tuna  E. lineatus
(Kishinouye, 1920)
0.84 m
(2.8 ft)
0.6 m
(2.0 ft)
11.8 kg
(26 lb)
3.83 [32][33] LC IUCN 3 1.svg Least concern[33]
Skipjack tuna Katsuwonus pelamis
(Linnaeus, 1758)
1.1 m
(3.6 ft)
0.8 m
(2.6 ft)
34.5 kg
(76 lb)
6–12 yrs 3.75 [34][35] LC IUCN 3 1.svg Least concern[35]

Biology[edit]

See also: Thunnus
Bigeye tuna Thunnus obesus showing finlets and keels. Finlets are found between the last dorsal and/or anal fin and the caudal fin. They are rayless and non-retractable.
Drawing by Dr Tony Ayling

Description[edit]

The tuna is a sleek and streamlined fish, adapted for speed. It has two closely spaced dorsal fins on its back; The first is "depressible" – it can be laid down, flush, in a groove that runs along its back. Seven to 10 yellow finlets run from the dorsal fins to the tail, which is lunate – curved like a crescent moon – and tapered to pointy tips. The caudal peduncle, to which the tail is attached, is quite thin, with three stabilizing horizontal keels on each side. The tuna's dorsal side is generally a metallic dark blue, while the ventral side, or underside, is silvery or whitish, for camouflage.[36]

Physiology[edit]

Thunnus are widely but sparsely distributed throughout the oceans of the world, generally in tropical and temperate waters between about 45 degrees north and south of the equator.[37] All tunas are able to maintain the temperature of certain parts of their body above the temperature of ambient seawater. For example, bluefin can maintain a core body temperature of 25–33 °C (77–91 °F), in water as cold as 6 °C (43 °F). However, unlike typical endothermic creatures such as mammals and birds, tuna do not maintain temperature within a relatively narrow range.[38][39]

Tuna achieve endothermy by conserving the heat generated through normal metabolism. The rete mirabile ("wonderful net"), the intertwining of veins and arteries in the body's periphery, allows much of the heat from venous blood to be "re-claimed" and transferred to the arterial blood via a counter-current exchange system, thus mitigating the effects of surface cooling. This allows the tuna to elevate the temperatures of the highly-aerobic tissues of the skeletal muscles, eyes and brain,[38][40] which supports faster swimming speeds and reduced energy expenditure, and which enables them to survive in cooler waters over a wider range of ocean environments than those of other fish.[39] In all tunas, however, the heart operates at ambient temperature, as it receives cooled blood, and coronary circulation is directly from the gills.[40]

Also unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red myotomal muscles derive their color from myoglobin, an oxygen-binding molecule, which tuna express in quantities far higher than most other fish. The oxygen-rich blood further enables energy delivery to their muscles.[38]

For powerful swimming animals like dolphins and tuna, cavitation may be detrimental, because it limits their maximum swimming speed.[41] Even if they have the power to swim faster, dolphins may have to restrict their speed, because collapsing cavitation bubbles on their tail are too painful. Cavitation also slows tuna, but for a different reason. Unlike dolphins, these fish do not feel the bubbles, because they have bony fins without nerve endings. Nevertheless, they cannot swim faster because the cavitation bubbles create a vapor film around their fins that limits their speed. Lesions have been found on tuna that are consistent with cavitation damage.[41]

Fishing industry[edit]

Bar chart that states Thunnus thynnus is the largest tuna, at 458 centimetres (180 in) followed by Thunnus orientalis at 300 centimetres (120 in), Thunnus obsesus at 250 centimetres (98 in), Gymnosarda unicolor at 248 centimetres (98 in), Thunnus maccoyii at 245 centimetres (96 in), Thunnus albacares at 239 centimetres (94 in), Gasterochisma melampus at 164 centimetres (65 in), Thunnus tonggol at 145 centimetres (57 in), Thunnus alalunga at 140 centimetres (55 in), Euthynnus alletteratus at 122 centimetres (48 in), Katsuwonus pelamis at 108 centimetres (43 in), Thunnus atlanticus at 108 centimetres (43 in), Allothunnus fallai at 105 centimetres (41 in), Euthynnus affinis at 100 centimetres (39 in), Auxis thazard thazard at 65 centimetres (26 in),Auxis rochei rochei at 50 centimetres (20 in), and Auxis rochei eudorax at 36.5 centimetres (14.4 in)
Maximum reported sizes of tuna species

Commercial fishing[edit]

Tuna is an important commercial fish. The International Seafood Sustainability Foundation (ISSF) compiled a detailed scientific report on the state of global tuna stocks in 2009, which includes regular updates. According to the ISSF, the most important species for commercial and recreational tuna fisheries are yellowfin (Thunnus albacares), bigeye (T. obesus), bluefin (T. thynnus, T. orientalis, and T. macoyii), albacore (T. alalunga), and skipjack (Katsuwonus pelamis).[37]

The report further states:

Between 1940 and the mid-1960s, the annual world catch of the five principal market species of tunas rose from about 300 thousand tons to about 1 million tons, most of it taken by hook and line. With the development of purse-seine nets, now the predominant gear, catches have risen to more than 4 million tons annually during the last few years. Of these catches, about 68 percent are from the Pacific Ocean, 22 percent from the Indian Ocean, and the remaining 10 percent from the Atlantic Ocean and the Mediterranean Sea. Skipjack makes up about 60 percent of the catch, followed by yellowfin (24 percent), bigeye (10 percent), albacore (5 percent), and bluefin the remainder. Purse-seines take about 62 percent of the world production, longline about 14 percent, pole and line about 11 percent, and a variety of other gears the remainder 3.[37]

The Australian government alleged in 2006 that Japan had illegally overfished southern bluefin by taking 12,000 to 20,000 tonnes per year instead of the their agreed 6,000 tonnes; the value of such overfishing would be as much as USD $2 billion.[42] Such overfishing has severely damaged bluefin stocks.[43] According to the WWF, "Japan's huge appetite for tuna will take the most sought-after stocks to the brink of commercial extinction unless fisheries agree on more rigid quotas".[44] Japan's Fisheries Research Agency counters that Australian and New Zealand tuna fishing companies under-report their total catches of southern bluefin tuna and ignore internationally mandated total allowable catch totals.[45]

In recent years, opening day fish auctions at Tokyo's Tsukiji fish market have seen record-setting prices for bluefin tuna, reflecting market demand. In each of 2010, 2011, 2012 and 2013, new record prices have been set for a single fish  – the current record is 155.4 million japanese yen (US $1.76 million) for a 221 kg (487 lb) bluefin, or a unit price of JP¥ 703,167/kg (US$ 3,603/lb). Prices plummeted in 2014.[46] A summary of record-setting auctions are shown in the following table (highlighted values indicate new world records):

Record bluefin tuna auctions at Tokyo's Tsukiji fish market
(highlighted field indicates new record price for a single fish)
Year Total
weight
Total sale Unit price Source
( JP ¥ ) ( US $ ) ( ¥ / kg ) ( $ / lb )
2001 202 kg
(445 lb)
¥ 20.2 million $ 173,600 ¥ 100,000 / kg $ 386 / lb [47]
2010 232 kg
(511 lb)
¥ 16.28 million $ 175,000 ¥ 70,172 / kg $ 343 / lb [48]
2011 342 kg
(754 lb)
¥ 32.49 million $ 396,000 ¥ 95,000 / kg $ 528 / lb [47]
2012 269 kg
(593 lb)
¥ 56.49 million $ 736,000 ¥ 210,000 / kg $ 1,247 / lb [49]
2013 221 kg
(487 lb)
¥ 155.4 million $ 1.76 million ¥ 703,167 / kg $ 3,603 / lb [50]

In November 2011, a different record was set when a fisherman in Massachusetts caught an 881-pound tuna. It was captured inadvertently using a dragnet. Due to the laws and restrictions on tuna fishing in the United States, federal authorities impounded the fish because it was not caught with a rod and reel. Because of the tuna's deteriorated condition as a result of the trawl net, the fish sold for just under $5,000.[51]

Fishing methods[edit]

External video
Tuna pole and line fishing BBC Two

Association with whaling[edit]

In 2005 Nauru, defending its vote from Australian criticism at that year's meeting of the International Whaling Commission, argued that some whale species have the potential to devastate Nauru's tuna stocks, and that Nauru's food security and economy relies heavily on fishing.[53] Despite this, Nauru does not permit whaling in its own waters and does not allow other fishing vessels to take or intentionally interact with marine mammals in its Exclusive Economic Zone. In 2010 and 2011 Nauru supported Australian proposals[54] for a western Pacific-wide ban on tuna purse-seining in the vicinity of marine mammals — a measure which was agreed by the Western and Central Pacific Fisheries Commission at its eighth meeting in March 2012.

Association with dolphins[edit]

Dolphins swim beside several tuna species. These include yellowfin tuna in the eastern Pacific Ocean, but not albacore. Tuna schools are believed to associate themselves with dolphins for protection against sharks, which are tuna predators.[55]

Commercial fishing vessels used to exploit this association by searching for dolphin pods. Vessels would encircle the pod with nets to catch the tuna beneath,[56] however the nets were prone to entangling dolphins, injuring or killing them. Public outcry and new government regulations, which are now monitored by NOAA have led to more "dolphin friendly" methods, now generally involving lines rather than nets. However, there are neither universal independent inspection programs nor verification of "dolphin safeness", so these protections are not absolute. According to Consumers Union, the resulting lack of accountability means claims that tuna that is "dolphin safe" should be given little credence.

Fishery practices have changed to be dolphin friendly, which has caused greater bycatch including sharks, turtles and other oceanic fish. Fishermen no longer follow dolphins, but concentrate their fisheries around floating objects such as fish aggregation devices, also known as FADs, which attract large populations of other organisms. Measures taken thus far to satisfy the public demand to protect dolphins can be potentially damaging to other species as well.[57]

Aquaculture[edit]

Increasing quantities of high-grade tuna are reared in net pens and fed bait fish. In Australia, former fishermen raise southern bluefin tuna, Thunnus maccoyii, and another bluefin species.[52] Farming its close relative, the Atlantic bluefin tuna, Thunnus thynnus, is beginning in the Mediterranean, North America and Japan. Hawaiʻi approved permits for the first U.S. offshore farming of bigeye tuna in water 1,300 feet (400 m) deep in 2009.[58]

Japan is the biggest tuna consuming nation and is also the leader in tuna farming research.[59] Japan first successfully farm-hatched and raised bluefin tuna in 1979. In 2002, it succeeded in completing the reproduction cycle and in 2007, completed a third generation.[60][61][62] The farm breed is known as Kindai tuna. Kindai is the contraction of Kinki University in Japanese (Kinki daigaku).[63] In 2009, Clean Seas, an Australian company which has been receiving assistance from Kinki University[64][65][66] managed to breed Southern Bluefin Tuna in captivity and was awarded the second place in World's Best Invention of 2009 by Time magazine.[67][68]

As food[edit]

Canned[edit]

Photo of grocery shelves
Canned tuna on sale at a supermarket

Canned tuna was first produced in 1903, quickly becoming popular.[69] Tuna is canned in edible oils, in brine, in water, and in various sauces. Tuna may be processed to be "chunked" or "flaked". In the United States, 52% of canned tuna is used for sandwiches; 22% for salads; and 15% for casseroles and dried, packaged meal mixes.[70]

In the United States, only Albacore can legally be sold in canned form as "white meat tuna";[71] in other countries, yellowfin is also acceptable. While in the early 1980s canned tuna in Australia was most likely Southern bluefin, as of 2003 it was usually yellowfin, skipjack, or tongol (labelled "northern bluefin").[69]

As tunas are often caught far from where they are processed, poor interim conservation can lead to spoilage. Tuna is typically gutted by hand, and later pre-cooked for prescribed times of 45 minutes to three hours. The fish are then cleaned and filleted, canned, and sealed, with the dark lateral blood meat often separately canned for pet food. The sealed can is then heated under pressure (called retort cooking) for 2 to 4 hours.[72] This process kills any bacteria, but retains the histamine that can produce rancid flavors. The international standard sets the maximum histamine level at 200 milligrams per kilogram. An Australian study of 53 varieties of unflavored canned tuna found none to exceed the safe histamine level, although some had "off" flavors.[69]

Australian standards once required cans of tuna to contain at least 51% tuna, but these regulations were dropped in 2003.[73][74] The remaining weight is usually oil or water. In the US, the FDA regulates canned tuna (see part c).[75]

Nutrition and health[edit]

Tuna, light, canned in oil, drained solids
Nutritional value per 100 g (3.5 oz)
Energy 830 kJ (200 kcal)
0 g
8 g
29 g
Vitamins
Vitamin A equiv.
(3%)
23 μg
Choline
(6%)
29 mg
Vitamin D
(45%)
269 IU
Trace metals
Calcium
(1%)
13 mg
Iron
(11%)
1.4 mg
Magnesium
(9%)
31 mg
Phosphorus
(44%)
311 mg
Potassium
(4%)
207 mg
Zinc
(9%)
0.9 mg
Other constituents
Water 60 g
Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database

Tuna can be a good source of omega-3 fatty acids. It can contain 300 milligrams (0.011 oz) per serving.[76] However, the level of omega-3 oils found in canned tuna is highly variable, since some common manufacturing methods destroy much of the omega-3 oils in the fish.[77] Tuna is also a good source of protein.

Mercury levels[edit]

See also: Mercury in fish

Mercury content in tuna can vary widely. For instance, testing by Rutgers University reportedly found that a can of StarKist had 10 times more mercury than another can of similarly identified tuna. This has prompted a Rutgers University scientist whose staff conducted the mercury analysis to say, "That's one of the reasons pregnant women have to be really careful ... If you happen to get a couple or three cans in the high range at a critical period when you are pregnant, it would not be good." Among those calling for improved warnings about mercury in tuna is the American Medical Association, which adopted a policy that physicians should help make their patients more aware of the potential risks.[78]

A study published in 2008 found that mercury distribution in the meat of farmed tuna is inversely related to the lipid content, suggesting that higher lipid concentration within edible tissues of tuna raised in captivity might, other factors remaining equal, have a diluting effect on mercury content.[79] These findings suggest that choosing to consume a type of tuna that has a relatively higher natural fat content might help reduce the amount of mercury intake, compared to consuming tuna with a low fat content.

Due to their high position in the food chain and the subsequent accumulation of heavy metals from their diet, mercury levels can be high in larger species such as bluefin and albacore.[citation needed]

In 2009 a California appeals court upheld a ruling that canned tuna does not need warning labels as the methylmercury is naturally occurring.[80]

In March 2004, the United States FDA issued guidelines recommending that pregnant women, nursing mothers, and children limit their intake of tuna and other predatory fish.[81] The Environmental Protection Agency provides guidelines on how much canned tuna it is safe to eat. Roughly speaking, the guidelines recommend one 6 oz. can of light tuna a week for those weighing less than 110 pounds and two cans a week for those who weigh more.[82]

In 2007 it was reported that some canned light tuna such as yellowfin tuna[83] is significantly higher in mercury than skipjack, and caused Consumers Union and other activist groups to advise pregnant women to refrain from consuming canned tuna.[84]

The Eastern little tuna (Euthynnus affinis) has been available for decades as a low-mercury, less expensive canned tuna. However, of the five major species of canned tuna imported by the United States it is the least commercially attractive, primarily due to its dark color and more pronounced 'fishy' flavor. Its use has traditionally been restricted to institutional (non-retail) commerce.

A January 2008 investigation conducted by the New York Times found potentially dangerous levels of mercury in certain varieties of sushi tuna, reporting levels "so high that the Food and Drug Administration could take legal action to remove the fish from the market."[85]

A book by Jane Hightower, Diagnosis Mercury: Money, Politics and Poison, published in 2008, discusses human exposure to mercury through eating large predatory fish such as large tuna.[86][87][88]

Management and conservation[edit]

Life cycle

There are five main tuna fishery management bodies: the Western Central Pacific Ocean Fisheries Commission, the Inter-American Tropical Tuna Commission, the Indian Ocean Tuna Commission, the International Commission for the Conservation of Atlantic Tunas and the Commission for the Conservation of Southern Bluefin Tuna.[89] The five gathered for the first time in Kobe, Japan in January 2007. Environmental organizations made submissions[90] on risks to fisheries and species. The meeting concluded with an action plan drafted by some 60 countries or areas. Concrete steps include issuing certificates of origin to prevent illegal fishing and greater transparency in the setting of regional fishing quotas. The delegates are scheduled to meet at another joint meeting in January or February 2009 in Europe.[91]

In 2010, Greenpeace International has added the albacore, bigeye tuna, Pacific bluefin tuna, Atlantic bluefin tuna, southern bluefin tuna and the yellowfin tuna to its seafood red list. "The Greenpeace International seafood red list is a list of fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries."[92][93]

It is widely accepted that bluefin tuna have been severely overfished, with some stocks at risk of collapse.[94][95] According to the International Seafood Sustainability Foundation (a global, non-profit partnership between the tuna industry, scientists, and the World Wide Fund for Nature), Indian Ocean yellowfin tuna, Pacific Ocean (eastern & western) bigeye tuna, and North Atlantic albacore tuna are all overfished. In April 2009, no stock of skipjack tuna (which makes up roughly 60 percent of all tuna fished worldwide) was considered to be overfished.[96] However, the BBC documentary South Pacific, which first aired in May 2009, stated that, should fishing in the Pacific continue at its current rate, populations of all tuna species could collapse within 5 years.[97] It highlighted huge Japanese and European tuna fishing vessels, sent to the South Pacific international waters after overfishing their own fish stocks to the point of collapse.

A 2010 tuna fishery assessment report, released in January 2012 by the Secretariat of the Pacific Community (SPC), supported this finding, recommending that all tuna fishing should be reduced or limited to current levels and that limits on skipjack fishing be considered.[98]

See also[edit]

References[edit]

  1. ^ a b c Graham, Jeffrey B.; Dickson, Kathryn A. (2004). "Tuna Comparative Physiology" (PDF). The Journal of Experimental Biology 207: 4015–4024. doi:10.1242/jeb.01267. Retrieved 20 September 2012. 
  2. ^ Block, Barbara A.; Booth, David; Carey, Francis G. (1992). "Direct measurement of swimming speeds and depth of blue marlin" (PDF). Journal of Experimental Biology (Company of Biologists Ltd.) 166: 267–284. ISSN 0022-0949. Retrieved 19 September 2012. 
  3. ^ a b c Collette B and 8 others (2011). "Thunnus maccoyii". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012.  "This species has been intensively fished since the early 1950s. Its generation length is conservatively estimated to be 12 years. Estimated spawning stock biomass has declined approximately 85% over the past 36 years (1973–2009) and there is no sign that the spawning stock is rebuilding. It is therefore listed as Critically Endangered. Implementation of effective conservation and management measures are urgently needed."
  4. ^ Liddell, H.G.; Scott, R.; Whiton, J.M. (1887). A lexicon abridged from Liddell and Scott's Greek-English lexicon (17th ed.). Ginn & Co. 
  5. ^ Collette, B.B. (1999). "Mackerels, molecules, and morphology". In Séret, B.; Sire, J.Y. Proceedings. 5th Indo-Pacific Fish Conference: Nouméa, New Caledonia, 3–8 November 1997. Paris: Société Française d'Ichtyologie [u.a.] pp. 149–164. ISBN 978-2-9507330-5-4. 
  6. ^ Tanaka, Y.; Satoh, K.; Iwahashi, M.; Yamada, H. (2006). "Growth-dependent recruitment of Pacific bluefin tuna Thunnus orientalis in the northwestern Pacific Ocean". Marine Ecology Progress Series 319: 225–235. doi:10.3354/meps319225. 
  7. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus alalunga" in FishBase. January 2012 version.
  8. ^ a b Collette B and 35 others (2011). "Thunnus alalunga". IUCN Red List of Threatened Species. Version 2012.2. International Union for Conservation of Nature. Retrieved 18 October 2012. 
  9. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus maccoyii" in FishBase. January 2012 version.
  10. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus obesus" in FishBase. January 2012 version.
  11. ^ a b Collette B and 31 others (2011). "Thunnus obesus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  12. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus orientalis" in FishBase. January 2012 version.
  13. ^ a b Collette B and 35 others (2011). "Thunnus orientalis". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  14. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus thynnus" in FishBase. January 2012 version.
  15. ^ a b Collette B and 23 others (2011). "Thunnus thynnus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  16. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus atlanticus" in FishBase. January 2012 version.
  17. ^ Collette B and 18 others (2011). "Thunnus atlanticus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  18. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus tonggol" in FishBase. January 2012 version.
  19. ^ a b Collette B and 7 others (2011). "Thunnus tonggol". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  20. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Thunnus albacares" in FishBase. January 2012 version.
  21. ^ a b Collette B and 35 others (2011). "Thunnus albacares". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  22. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Allothunnus fallai" in FishBase. January 2012 version.
  23. ^ Collette B and 18 others (2011). "Allothunnus fallai". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  24. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Auxis rochei" in FishBase. January 2012 version.
  25. ^ a b Collette B and 28 others (2011). "Auxis rochei". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  26. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Auxis thazard" in FishBase. January 2012 version.
  27. ^ Collette B and 28 others (2011). "Auxis thazard". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  28. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Euthynnus affinis" in FishBase. January 2012 version.
  29. ^ a b Collette B and 6 others (2011). "Euthynnus affinis". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  30. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Euthynnus alletteratus" in FishBase. January 2012 version.
  31. ^ Collette B and 17 others (2011). "Euthynnus alletteratus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  32. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Euthynnus lineatus" in FishBase. January 2012 version.
  33. ^ a b Collette B and 11 others (2011). "Euthynnus lineatus". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  34. ^ Froese, Rainer and Pauly, Daniel, eds. (2012). "Katsuwonus pelamis" in FishBase. January 2012 version.
  35. ^ a b Collette B and 28 others (2011). "Katsuwonus pelamis". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 18 September 2012. 
  36. ^ Gibbs, E. "Fact Sheet: Tuna #P1412". Rhode Island Sea Grant. Retrieved 20 September 2012. 
  37. ^ a b c "Status of the World Fisheries for Tuna: Section A-1 – Introduction". ISSF. 15 April 2009. Archived from the original on 2010-03-27. Retrieved 2009-11-10. 
  38. ^ a b c Sepulveda, C.A.; Dickson, K.A.; Bernal, D.; Graham, J.B. (1 July 2008). "Elevated red myotomal muscle temperatures in the most basal tuna species, Allothunnus fallai". Journal of Fish Biology 73 (1): 241–249. doi:10.1111/j.1095-8649.2008.01931.x. Retrieved 2 November 2012. 
  39. ^ a b "Tuna — Biology Of Tuna". Retrieved September 12, 2009. 
  40. ^ a b Landeira-Fernandez, A.M.; Morrissette, J.M.; Blank, J.M.; Block, B.A. (16 October 2003). "Temperature dependence of the Ca2+-ATPase (SERCA2) in the ventricles of tuna and mackerel". American Journal of Physiology: Regulatory, Integrative and Comparative Physiology 286 (2): R398–R404. doi:10.1152/ajpregu.00392.2003. 
  41. ^ a b Brahic, Catherine (2008-03-28). "Dolphins swim so fast it hurts". NewScientist. Retrieved 2008-03-31. 
  42. ^ Bradford, Gillian (October 16, 2006). "Bluefin Tuna Plundering Catches Up With Japan". ABC News. Retrieved 11 August 2013. 
  43. ^ Eilperin, Juliet (November 29, 2009). "Global approach now favored for marine conservation". Washington Post. Retrieved 11 August 2013. 
  44. ^ McCurry, Justin (January 22, 2007). "Japan warned tuna stocks face extinction". The Guardian (London). Retrieved 2008-04-02. 
  45. ^ Wright, Hillel (9 January 2011). "Are Japan's fish lovers eating tuna to extinction?". Japan Times. p. 7. Retrieved 11 August 2013. 
  46. ^ "Price of tuna nosedives at famous Tokyo auction despite dwindling stocks". The Toronto Star. January 5, 2014. Retrieved 8 February 2014. 
  47. ^ a b "Fish story: Big tuna sells for record $396,000". NBCNews.com. January 5, 2011. Retrieved 19 September 2012. 
  48. ^ Buerk, Roland (5 January 2010). "Tuna hits highest price in nine years at Tokyo auction". BBC News. Retrieved 19 September 2012. 
  49. ^ "A single fish sells for nearly three-quarters of a million dollars". NBCNews.com. January 5, 2012. Retrieved 19 September 2012. 
  50. ^ "A bluefin tuna sells for record $1.76M in Tokyo". usatoday.com. January 4, 2013. Retrieved 4 January 2013. 
  51. ^ "Man catches 881-pound tuna, seized by feds | The Sideshow — Yahoo! News". News.yahoo.com. 2011-11-15. Retrieved 2012-06-16. 
  52. ^ a b Doolette, DJ and Craig, D (1999). "Tuna farm diving in South Australia". South Pacific Underwater Medicine Society Journal 29 (2). ISSN 0813-1988. OCLC 16986801. Retrieved 2008-08-17. 
  53. ^ Dorney, Sean (2005-06-28). "Nauru defends whaling vote. 28/06/2005. ABC News Online". Abc.net.au. Retrieved 2012-04-12. 
  54. ^ Western and Central Pacific Fisheries Commission. "Australia Proposals to Address the Impact of Purse Seine Fishing Activity on Cetaceans". WCPFC. Retrieved 11 April 2012. 
  55. ^ "ENSENADA: El Puerto del Atun". Journalism.berkeley.edu. Retrieved 2010-09-22. 
  56. ^ "Dolphin-safe tuna". Whale and Dolphin Conservation. 
  57. ^ "The ecological disaster that is dolphin safe tuna". Southern Fried Science. 
  58. ^ McAvoy, Audrey (October 24, 2009). "Hawaii regulators approve first US tuna farm". Associated Press. Retrieved August 11, 2013. 
  59. ^ Susannah F. Locke (17 March 2008). "Breeding the Overfished Bluefin Tuna". LiveScience. Retrieved 13 May 2013. 
  60. ^ "The holy grail of fish breeding". 
  61. ^ "Cultivation, seedling production, and selective breeding of bluefin tuna and other fish at the Kinki University Fisheries Laboratory". Flku.jp. Retrieved 2010-09-22. 
  62. ^ Jung, Carolyn (2008-05-21). "The rarest tuna of all — Japan's farmed Kindai". The San Francisco Chronicle. 
  63. ^ Raisfeld, Robin (2008-05-04). "Can a Farmed Bluefin Tuna Save the Planet? - New York Magazine". Nymag.com. Retrieved 2012-06-16. 
  64. ^ "FNArena". FNArena. 2009-05-15. Retrieved 2010-09-22. 
  65. ^ "Stateline South Australia". Abc.net.au. Retrieved 2010-09-22. 
  66. ^ Austin, Nigel (2008-09-23). "Clean Seas teams up with Japan's Kinki Uni for tuna research". The Advertiser. 
  67. ^ "The Tank-Bred Tuna". The 50 Best Inventions of 2009 (Time.com). 2009-11-12. Retrieved 21 January 2013. 
  68. ^ "Aussies Win ‘Best Invention’ Award". ThinkingAustralia.com. Retrieved 21 January 2013. 
  69. ^ a b c Choice: Jan/Feb 2004.
  70. ^ "Tuna". Modern Marvels, 4 February 2010.
  71. ^ Ellis, Richard. Tuna: A Love Story. New York: Random House, 2009, p. 119. ISBN 0-307-38710-0
  72. ^ "The tuna processing industry". U.S. Department of Labor. Retrieved 11 August 2013. 
  73. ^ Choice, August 2003.
  74. ^ [1][dead link]
  75. ^ "CFR — Code of Federal Regulations Title 21". Accessdata.fda.gov. Retrieved 2010-09-22. 
  76. ^ "Omega-3 Centre". Omega-3 sources. Omega-3 Centre. Archived from the original on 2008-07-18. Retrieved 2008-07-27. 
  77. ^ Is canned tuna a good source of omega 3 fats? WHFoods. Retrieved 22 September 2012.
  78. ^ Roe, Sam; Hawthorne, Michael. "How safe is tuna?". Chicago Tribune. [dead link]
  79. ^ Balshaws, S.; J.W. Edwards, K.E. Ross, and B.J. Daughtry (December 2008). "Mercury distribution in the muscular tissue of farmed southern bluefin tuna (Thunnus maccoyii) is inversely related to the lipid content of tissues". Food Chemistry 111 (3): 616–621. doi:10.1016/j.foodchem.2008.04.041. Retrieved March 30, 2010. 
  80. ^ "California Court of Appeals Ruling". March 2009. Retrieved 2009-03-25. [dead link]
  81. ^ "What You Need to Know About Mercury in Fish and Shellfish". March 2004. Retrieved 2007-05-19. 
  82. ^ "PROTECT YOURSELF AND YOUR FAMILY: Eating Tuna Safely". 2012-04-02. Retrieved 2012-04-02. 
  83. ^ "FDA to check tuna". Chicago Tribune. Retrieved 2007-06-21. 
  84. ^ "Mercury in tuna". June 2006. Retrieved 2007-05-19. 
  85. ^ Burros, Marian (January 23, 2008). "High Mercury Levels Are Found in Tuna Sushi". New York Times. Retrieved September 11, 2009. 
  86. ^ Jane Hightower (2008). Diagnosis Mercury: Money, Politics and Poison, Island Press, p. 250.
  87. ^ Review: Diagnosis: Mercury by Jane Hightower
  88. ^ Diagnosis Mercury: Money, Politics and Poison by Jane M. Hightower
  89. ^ "WWF demands tuna monitoring system". The Age (Melbourne). 2007-01-19. Retrieved 2008-05-19. 
  90. ^ "Briefing: Joint Tuna RFMO Meeting, Kobe 2007". 2007-01-23. Retrieved 2008-05-19. [dead link]
  91. ^ "Conference approves global plan to save tuna stocks". 2007-01-26. Retrieved 2008-05-10. [dead link]
  92. ^ "Greenpeace International Seafood Red list". Greenpeace.org. 2003-03-17. Retrieved 2010-09-22. [dead link]
  93. ^ Greenberg, Paul (2010-06-21). "Tuna's End". The New York Times. 
  94. ^ Black, Richard (17 October 2007). "Last rites for a marine marvel?". BBC News Online. Retrieved 2007-10-17. 
  95. ^ Ito, Masami, "Does Japan's affair with tuna mean loving it to extinction?", Japan Times, August 31, 2010, p. 3.
  96. ^ "Status of the World Fisheries for Tuna: Section A-2 – Summary". ISSF. 15 April 2009. Archived from the original on 2010-03-27. Retrieved 2009-11-10. 
  97. ^ Produced and directed by Jonathan Clay (2009-06-14). "Fragile Paradise". South Pacific. BBC. BBC Two.
  98. ^ "Tuna overfishing continues". Cook Islands News. 12 Jan 2012. Retrieved 2012-05-19. 

Further references[edit]

External links[edit]

News[edit]