The Atlantic bluefin tuna (''Thunnus thynnus'') is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max len ...
in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Scombridae
The mackerel, tuna, and bonito family, Scombridae, includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies. All species are in the subfamily Scombrinae, except the butterf ...
. It is variously known as the northern bluefin tuna (mainly when including
Pacific bluefin as a subspecies), giant bluefin tuna
or individuals exceeding and formerly as the tunny.
Atlantic bluefins are native to both the western and eastern Atlantic Ocean, as well as the
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
. They have become extinct in the
Black Sea
The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
. The Atlantic bluefin tuna is a close relative of the other two bluefin tuna species—the Pacific bluefin tuna and the
southern bluefin tuna
The southern bluefin tuna (''Thunnus maccoyii'') is a tuna of the family Scombridae found in open southern Hemisphere waters of all the world's oceans mainly between 30°S and 50°S, to nearly 60°S. At up to and weighing up to , it is among ...
.
Atlantic bluefin tuna have been recorded at up to in weight, and rival the
black marlin
The black marlin (''Istiompax indica'') is a species of marlin found in tropical and subtropical areas of the Indian and Pacific Oceans. With a maximum published length of and weight of , it is one of the largest marlins and also one of the la ...
,
blue marlin
''Makaira'' (Latin via Greek: ''μαχαίρα'' "sword") is a genus of marlin in the family Istiophoridae. It includes the Atlantic blue, and Indo-Pacific blue marlins. In the past, the black marlin was also included in this genus, but today ...
, and
swordfish as the largest
Perciformes
Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means ...
. Throughout recorded history, the Atlantic bluefin tuna has been highly prized as a
food fish
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ing ...
. Besides their commercial value as food, the great size, speed, and power they display as
apex predator
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
s has attracted the admiration of fishermen, writers, and scientists.
The Atlantic bluefin tuna has been the foundation of one of the world's most lucrative commercial fisheries. Medium-sized and large individuals are heavily targeted for the
Japanese raw-fish market, where all bluefin species are highly prized for
sushi
is a Japanese dish of prepared , usually with some sugar and salt, accompanied by a variety of , such as seafood, often raw, and vegetables. Styles of sushi and its presentation vary widely, but the one key ingredient is "sushi rice," also ...
and
sashimi
is a Japanese delicacy consisting of fresh raw fish or meat sliced into thin pieces and often eaten with soy sauce.
Origin
The word ''sashimi'' means "pierced body", i.e. " 刺身" = ''sashimi'', where 刺 し = ''sashi'' (pierced, stu ...
.
This commercial importance has led to severe
overfishing. The
affirmed in October 2009 that Atlantic bluefin tuna stocks had declined dramatically over the last 40 years, by 72% in the Eastern Atlantic, and by 82% in the Western Atlantic. On 16 October 2009,
Monaco
Monaco (; ), officially the Principality of Monaco (french: Principauté de Monaco; Ligurian: ; oc, Principat de Mónegue), is a sovereign city-state and microstate on the French Riviera a few kilometres west of the Italian region of Lig ...
formally recommended endangered Atlantic bluefin tuna for an Appendix I
CITES
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
listing and international trade ban. In early 2010, European officials, led by the French ecology minister, increased pressure to ban the
commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...
of bluefin tuna internationally.
However, a UN proposal to protect the species from international trade was voted down (68 against, 20 for, 30 abstaining).
[
] Since then, enforcement of regional fishing quotas has led to some increases in population. the Atlantic bluefin tuna was moved from the category of Endangered to the category of Least Concern on the
IUCN Red List of Threatened Species. However, many regional populations are still severely depleted, including western stocks which spawn in the Gulf of Mexico.
Most bluefins are captured commercially by professional fishermen using
longlines,
purse seine
Seine fishing (or seine-haul fishing; ) is a method of fishing that employs a surrounding net, called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be de ...
s, assorted hook-and-line gear, heavy
rods and reels, and
harpoon
A harpoon is a long spear-like instrument and tool used in fishing, whaling, sealing, and other marine hunting to catch and injure large fish or marine mammals such as seals and whales. It accomplishes this task by impaling the target animal ...
s. Recreationally, bluefins have been one of the most important big-game species sought by sports fishermen since the 1930s, particularly in the United States, but also in Canada, Spain, France, and Italy.
Taxonomy
The Atlantic bluefin tuna was one of the many
fish species originally described by
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in his landmark 1758
10th edition
1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. ...
of ''
Systema Naturae'', where it was given the binomial name ''Scomber thynnus''.
It is most closely related to the Pacific bluefin tuna (''T. orientalis'') and the southern bluefin tuna (''T. maccoyii''), and more distantly to the other large tunas of the genus ''
Thunnus
''Thunnus'' is a genus of ocean-dwelling, ray-finned bony fish from the mackerel family, Scombridae. More specifically, ''Thunnus'' is one of five genera which make up the tribe Thunnini – a tribe that is collectively known as the tunas. ...
'' – the
bigeye tuna
The bigeye tuna (''Thunnus obesus'') is a species of true tuna of the genus '' Thunnus'', belonging to the wider mackerel family Scombridae. In Hawaiian, it is one of two species known as ahi, the other being the yellowfin tuna. Bigeye tuna are ...
(''T. obesus'') and the
yellowfin tuna
The yellowfin tuna (''Thunnus albacares'') is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide.
Yellowfin is often marketed as ahi, from the Hawaiian , a name also used there for the closely related bigeye ...
(''T. albacares'').
[Collette, B.B. (1999). ''Mackerels, molecules, and morphology.'' In: Proceedings of the 5th Indo-Pacific Fish Conference, Noumea. pp. 149–164] For many years, the Pacific and Atlantic bluefin tuna species were considered to be the same, or subspecies, and referred to as the "northern bluefin tuna".
[ This name occasionally gives rise to some confusion, as the ]longtail tuna
''Thunnus tonggol'' is a species of tuna of tropical Indo-West Pacific waters.
It is commonly known as the longtail tuna or northern bluefin tuna.Hutchins, B. & Swainston, R. (1986). ''Sea Fishes of Southern Australia.'' pp. 104 & 141. Allen, G. ...
(''T. tonggol'') can in Australia sometimes be known under the name "northern bluefin tuna".[Hutchins, B. & Swainston, R. (1986). ''Sea Fishes of Southern Australia.'' pp. 104 & 141. ][Allen, G. (1999). ''Marine Fishes of Tropical Australia and South-East Asia.'' p. 230. ] This is also true in New Zealand and Fiji.
Bluefin tuna were often referred to as the common tunny, especially in the UK, Australia, and New Zealand. The name "tuna", a derivative of the Spanish ''atún'', was widely adopted in California in the early 1900s, and has since become accepted for all tunas, including the bluefin, throughout the English-speaking world. In some languages, the red color of the bluefin's meat is included in its name, as in ''atún rojo'' (Spanish) and ''tonno rosso'' (Italian), amongst others.
Description
The body of the Atlantic bluefin tuna is rhomboidal in profile and robust. The head is conical and the mouth rather large. The head contains a "pineal window" that allows the fish to navigate over its multiple thousands-of-miles range.[ Their color is dark blue above and gray below, with a gold coruscation covering the body and bright yellow caudal finlets. Bluefin tuna can be distinguished from other family members by the relatively short length of their ]pectoral fin
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...
s. Their liver
The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...
s have a unique characteristic in that they are covered with blood vessels (striated). In other tunas with short pectoral fins, such vessels are either not present or present in small numbers along the edges.
Fully mature adult specimens average long and weigh around .[Atlantic Bluefin Tuna (''Thunnus thynnus'')]
Nmfs.noaa.gov. Retrieved on 4 May 2013. The largest recorded specimen taken under International Game Fish Association rules was caught off Nova Scotia
Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland".
Most of the population are native Eng ...
, an area renowned for huge Atlantic bluefin, and weighed and was long. The longest contest between man and tuna fish occurred near Liverpool
Liverpool is a city and metropolitan borough in Merseyside, England. With a population of in 2019, it is the 10th largest English district by population and its metropolitan area is the fifth largest in the United Kingdom, with a populat ...
, Nova Scotia in 1934, when six men taking turns fought a tuna for 62 hours. Both the Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
and the U. S. National Marine Fisheries Service have accepted that this species can weigh up to , though further details are lacking.[Burnie D and Wilson DE (Eds.), ''Animal: The Definitive Visual Guide to the World's Wildlife''. DK Adult (2005), ] Atlantic bluefin tuna reach maturity relatively quickly. In a survey that included specimens up to in length and in weight, none was believed to be older than 15 years. However, very large specimens may be up to 50 years old.[
The bluefin possesses enormous muscular strength, which it channels through a pair of tendons to its lunate-shaped caudal fin for propulsion. In contrast to many other fish, the body stays rigid while the tail flicks back and forth, increasing stroke efficiency. It also has a very efficient circulatory system. It possesses one of the highest blood-hemoglobin concentrations among fish, which allows it to efficiently deliver oxygen to its tissues; this is combined with an exceptionally thin blood-water barrier to ensure rapid oxygen uptake.]
To keep its core muscles warm, which are used for power and steady swimming, the Atlantic bluefin uses countercurrent exchange
Countercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some chemical, between two flowing bodies flowing in opposite directions to each ...
to prevent heat from being lost to the surrounding water. Heat in the venous blood
Venous blood is deoxygenated blood which travels from the peripheral blood vessels, through the venous system into the right atrium of the heart. Deoxygenated blood is then pumped by the right ventricle to the lungs via the pulmonary artery wh ...
is efficiently transferred to the cool, oxygenated arterial blood
Arterial blood is the oxygenated blood in the circulatory system found in the pulmonary vein, the left chambers of the heart, and in the artery, arteries. It is bright red in color, while venous blood is dark red in color (but looks purple through ...
entering a rete mirabile
A rete mirabile (Latin for "wonderful net"; plural retia mirabilia) is a complex of arteries and veins lying very close to each other, found in some vertebrates, mainly warm-blooded ones. The rete mirabile utilizes countercurrent blood flow within ...
. While all members of the tuna family are warm-blooded, the ability to thermoregulate is more highly developed in bluefin tuna than in any other fish. This allows them to seek food in the rich but chilly waters of the North Atlantic.
Biology and ecology
Bluefins dive to depths of .[ The Atlantic bluefin tuna typically hunts small fish such as ]sardine
"Sardine" and "pilchard" are common names for various species of small, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century, a folk etymology says it comes from the It ...
s, herring, and mackerel, and invertebrates such as squid and crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s. They exhibit opportunistic hunting in schools of fish organised by size. Their white skeletal muscle allows for large contractions which aids burst swimming to ensure prey capture.
The species is host to over 70 parasites
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
although none have been yet described as causing harm to the species. The tetraphyllidean tapeworm
Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cesto ...
'' Pelichnibothrium speciosum'' is one parasite of the species. As the tapeworm's definite host is the blue shark, which does not generally seem to feed on tuna, the Atlantic bluefin tuna likely is a dead-end host for ''P. speciosum''.
Life history
Bluefin tuna are oviparous, congregating together in large groups to spawn. Over several days, a female releases large numbers of eggs into the water where they are fertilized externally by male sperm. Female bluefins have been estimated to produce a mean
There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value (magnitude and sign) of a given data set.
For a data set, the '' ari ...
of 128.5 eggs per gram of body weight, or up to 40 million eggs at a time. Eggs hatch into larvae two days after fertilization and become cannibalistics quarter-inch long fish by the end of a week. About 40% of larvae survive their first week, and about 0.1% the first year. Surviving bluefin tend to group together in schools according to size.
Atlantic bluefin tuna were traditionally known to spawn in two widely separated areas. Pop-up satellite tracking results generally confirm the belief held by many scientists and fishermen that although bluefin that were spawned in each area may forage widely across the Atlantic, the vast majority return to their natal area to spawn.
The Eastern stock of Atlantic bluefins' spawning ground exists in the western Mediterranean
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...
, particularly in the area of the Balearic Islands. The spawning ground of the Western stock is the Gulf of Mexico
The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...
. Because Atlantic bluefins group together in large concentrations to spawn, they are highly vulnerable to commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...
while spawning. This is particularly so in the Mediterranean, where the groups of spawning bluefins can be spotted from the air by light aircraft and purse seines directed to set around the schools.
In 2016, researchers suggested that a third spawning area exists in the Slope Sea, an area to the north and west of the Northeastern United States Continental Shelf. Subsequent research indicates that comparable concentrations of bluefin larvae are found in the Slope Sea and in the Gulf of Mexico.
A number of behavioral differences have been observed between the eastern and western populations, some of which may reflect environmental conditions. For example, bluefin in the Gulf of Mexico spawn between mid-April and mid-June, when the surface water temperature is between and , while bluefin in the Mediterranean spawn between June and August, when water is between and . In the Gulf of Mexico bluefin appear to correct for higher surface temperatures by diving, going deeper than when entering the Gulf and staying deeper than to spawn.
The western and eastern populations have been thought to mature at different ages. Bluefins born in the east are thought to reach maturity a year or two earlier than those spawned in the west. It has also been suggested that these apparent differences may reflect not-well-understood complexities of migration patterns and additional spawning areas such as the Slope Sea.
Human interaction
Ancient fishery
According to Longo, "by the turn of the first millennium CE, a sophisticated bluefin tuna trap fishery ademerged. ... This trap fishery, called tonnara in Italian, madrague in French, almadraba in Spanish, and armação in Portuguese, forms an elaborate maze of nets that capture and corral bluefin tuna during their spawning season. Active for more than a thousand years, the traditional/artisanal bluefin tuna trap fishery has experienced a collapse in the Mediterranean and has struggled where it is still practiced."
Commercial fishery
After World War II, Japanese fishermen needed more tuna to eat and to export for European and U.S. canning industries. They expanded their fishing range and perfected industrial long-line fishing, a practice that employs thousands of baited hooks on miles-long lines. In the 1970s, Japanese manufacturers developed lightweight, high-strength polymers that were spun into drift net
Drift netting is a fishing technique where nets, called drift nets, hang vertically in the water column without being anchored to the bottom. The nets are kept vertical in the water by floats attached to a rope along the top of the net and weig ...
. Though they were banned on the high seas by the early 1990s, in the 1970s, hundreds of miles of them were often deployed in a single night. At-sea freezing technology then allowed them to bring frozen sushi-ready tuna from the farthest oceans to market after as long as a year.[
The initial target was yellowfin tuna. Japanese did not value bluefin before the 1960s. By the late 1960s, ]sportfishing
Recreational fishing, also called sport fishing or game fishing, is fishing for leisure, exercise or competition. It can be contrasted with commercial fishing, which is professional fishing for profit; or subsistence fishing, which is fishing ...
for giant bluefin tuna was burgeoning off Nova Scotia, New England, and Long Island. North Americans, too, had little appetite for bluefins, usually discarding them after taking a picture. Bluefin sportfishing's rise, however, coincided with Japan's export boom. In the 1960s and '70s, cargo planes were returning to Japan empty. A Japanese entrepreneur realized he could buy New England and Canadian bluefins cheaply, and started filling Japan-bound holds with tuna. Exposure to beef and other fatty meats during the U.S. occupation following World War Two had prepared the Japanese palate for bluefin's fatty belly (''otoro''). The Atlantic bluefin was the biggest and the favorite. The appreciation rebounded across the Pacific when Americans started to eat raw fish in the late 1970s.[
Prior to the 1960s, Atlantic bluefin fisheries were relatively small scale, and populations remained stable. Although some local stocks, such as those in the North Sea, were damaged by unrestricted ]commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...
, other populations were not at risk. However, in the 1960s, purse seiners
A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds of vessels are used in commercial, artisanal and recreational fishing.
The total number of fishing vessels in the world in 2016 was es ...
catching fish for the canned tuna market in United States coastal waters removed huge numbers of juvenile and young Western Atlantic bluefins, taking out several entire-year classes. Mediterranean fisheries have historically been poorly regulated and catches under-reported, with French, Spanish, and Italian fishermen competing with North African nations for a diminishing population. The fish's migratory habits complicate the task of regulating the fishery, because they spend time in the national waters of multiple countries, as well as the open ocean outside of any national jurisdiction.[
]
Aquaculture
Tuna ranching began as early as the 1970s. Canadian fishermen in St Mary's Bay captured young fish and raised them in pens. In captivity, they grow to reach hundreds of kilos, eventually fetching premium prices in Japan. Ranching enables ranchers to exploit the unpredictable supply of wild-caught fish. Ranches across the Mediterranean and off South Australia grow bluefins offshore. According to OECD statistics, 35 thousand tons have been produced in 2018 with Japan accounting for about 50% of it, followed by Australia, Mexico, Spain and Turkey with smaller amounts. Large proportions of juvenile and young Mediterranean fish are taken to be grown on tuna farms. Because the tuna are taken from the wild to the pens before they are old enough to reproduce, ranching is one of the most serious threats to the species. The bluefin's slow growth and late sexual maturity compound its problems. The Atlantic population has declined by nearly 90% since the 1970s.
In Europe and Australia, scientists have used light-manipulation technology and time-release hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are require ...
implants to bring about the first large-scale captive spawning of Atlantic and southern bluefins.[ The technology involves implanting ]gonadotropin-releasing hormone
Gonadotropin-releasing hormone (GnRH) is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is a tropic peptide hormone synthesized and release ...
in the fish to stimulate fertile egg production and may push the fish to reach sexual maturity at younger ages.
However, since bluefins require so much food per unit of weight gained - up to 10 times that of salmon - if bluefins were to be farmed at the same scale as 21st-century salmon farming, many of their prey species might become depleted if farmed bluefin were fed the same diet as their wild counterparts. As of 2010, 30 million tons of small forage fish were removed from the oceans yearly, the majority to feed farmed fish.[
Market entry by many North African Mediterranean countries, such as ]Tunisia
)
, image_map = Tunisia location (orthographic projection).svg
, map_caption = Location of Tunisia in northern Africa
, image_map2 =
, capital = Tunis
, largest_city = capital
, ...
and Libya
Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to the east, Suda ...
in the 1990s, along with the increasingly widespread practice of tuna farming in the Mediterranean and other areas, such as southern Australia (for southern bluefin tuna), depressed prices. One result is that fishermen must now catch up to twice as many fish to maintain their revenues.
The Atlantic bluefin is endangered.
Threats
Global appetite for fish is the predominant threat to Atlantic bluefin. Overfishing continues despite repeated warnings of the current precipitous decline. Bluefin aquaculture, which arose in response to declining wild stocks, has yet to achieve a sustainability, in part because it predominantly relies on harvesting and ranching juveniles rather than captive breeding.
The 2010 Deepwater Horizon oil spill
The ''Deepwater Horizon'' oil spill (also referred to as the "BP oil spill") was an industrial disaster that began on 20 April 2010 off of the coast of the United States in the Gulf of Mexico on the BP-operated Macondo Prospect, considere ...
released an estimated 4.9 million barrels of crude oil into the Gulf of Mexico during the spawning season of the Atlantic bluefin tuna. The oil is estimated to have affected roughly 3.1 million square miles, including more than 5 percent of the tuna habitat in the U.S. Exclusive Economic Zone. The spill occurred at a peak time for the fertilization of eggs and the development of larval bluefin tuna. Resulting short and long-term impacts on populations of Atlantic bluefin tuna and other pelagic species are difficult to determine, in part due to limitations in monitoring ability.
Nonetheless, a number of lethal and sublethal impacts have been documented, including pericardial edema, defective cardiac function and cardiac abnormalities.
Conservation
Fisheries management organizations
In 2007, researchers from the (ICCAT) — the regulators of Atlantic bluefin fishing—recommended a global quota of 15,000 tonnes to maintain current stocks or 10,000 tonnes to allow the fisheries recovery. ICCAT then chose a quota of 36,000 tonnes, but surveys indicated that up to 60,000 tonnes were actually being taken (a third of the total remaining stocks) and the limit was reduced to 22,500 tonnes. Their scientists now say that 7500 tonnes are the sustainable limit. In November 2009, ICCAT set the 2010 quota at 13,500 tonnes and said that if stocks were not rebuilt by 2022, it would consider closing some areas.[
On 18 March 2010, the United Nations rejected a U.S.-backed effort to impose a total ban on Atlantic bluefin tuna fishing and trading. The ]Convention on International Trade in Endangered Species
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
(CITES) vote was 68 to 20 with 30 European abstentions. The leading opponent, Japan, claimed that ICCAT was the proper regulatory body.
In 2011, the USA's National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
(NOAA) decided not to list the Atlantic bluefin tuna as an endangered species. NOAA officials said that the more stringent international fishing rules created in November 2010 would be enough for the Atlantic bluefin tuna to recover. NOAA agreed to reconsider the species' endangered status in 2013. It was made a National Marine Fisheries Service
The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the ste ...
species of concern, one of those species about which the U.S. government has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act.
In November 2012, 48 countries meeting in Morocco for the International Commission for the Conservation of Atlantic Tunas voted to keep strict fishing limits, saying the species' population is still fragile. The quota will rise only slightly, from 12,900 metric tons a year to 13,500. The decision was reviewed in November 2014, resulting in higher allowances listed below.
The latest stock assessment for Atlantic bluefin tuna reflected an improvement in the status for both western and eastern Atlantic/Mediterranean stocks. The Commission adopted new management measures that are within the range of scientific advice, are consistent with the respective rebuilding plans, and allow for continued stock growth. For the western stock, the TAC of 2,000 mt annually for 2015 and 2016 will provide for continued growth in spawning stock biomass and allow the strong 2003 year-class to continue to enhance the productivity of the stock. The TAC for the eastern Atlantic/Mediterranean stock was set at 16,142 t for 2015; 19,296 t for 2016; and 23,155 t for 2017.
In 2020, the UK government recognised the increasing incidence of bluefin tuna in UK waters in recent years and is funding ongoing research to understand the ecology of the species and devise an approach to its management.
Other organizations
In 2010, Greenpeace International
Greenpeace is an independent global campaigning network, founded in Canada in 1971 by Irving Stowe and Dorothy Stowe, immigrant environmental activists from the United States. Greenpeace states its goal is to "ensure the ability of the Earth t ...
added the northern bluefin tuna to its seafood red list. As of January 2022, the bluefin tuna remains on the list.
In the summer of 2011, the Sea Shepherd Conservation Society
The Sea Shepherd Conservation Society (SSCS) is a non-profit, marine conservation activism organization based in Friday Harbor on San Juan Island, Washington, in the United States. Sea Shepherd employs direct action tactics to achieve its g ...
led a campaign against supposedly illegal bluefin tuna fishing off the coast of Libya, which was under Muammar Gaddafi's regime at the time. The fishermen retaliated against Sea Shepherd's intervention by throwing various, small metal pieces at the crew. Nobody was injured due to the other side's actions during the conflict.[Operation Blue Rage 2011](_blank)
. Seashepherd.org. Retrieved on 1 May 2015.
In November 2011, food critic Eric Asimov
Eric Asimov (born July 17, 1957) is an American wine critic and food critic for ''The New York Times''.
Early life
Asimov was born in Bethpage, New York, the son of Stanley Asimov, former vice-president for editorial administration at ''News ...
of ''The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid d ...
'' criticized the top-ranked New York City restaurant Sushi Yasuda
Sushi Yasuda is a Japanese sushi restaurant located at 204 East 43rd Street (between Second Avenue and Third Avenue) in the Midtown East area of Manhattan, New York City.
The restaurant was founded in 1999 by its former chef, Naomichi Yasuda of ...
for offering bluefin tuna on their menu, arguing that drawing from such a threatened fishery constituted an unjustifiable risk to bluefins, and to the future of culinary traditions that depend on the species.
The bluefin species are listed by the Monterey Bay Aquarium
Monterey Bay Aquarium is a nonprofit public aquarium in Monterey, California. Known for its regional focus on the marine habitats of Monterey Bay, it was the first to exhibit a living kelp forest when it opened in October 1984. Its biologists ...
on its Seafood Watch __NOTOC__
Seafood Watch is a sustainable seafood advisory list, and has influenced similar programs around the world. It is best known for developing science-based seafood recommendations that consumers, chefs, and business professionals use to i ...
list and pocket guides as fish to avoid due to overfishing.Tuna, Bluefin – Seafood Watch
Montereybayaquarium.org. Retrieved on 4 May 2013.
Cuisine
Atlantic bluefin tuna is one of the most highly prized fish used in Japanese raw fish dishes. About 80% of the caught Atlantic and Pacific bluefin tunas are consumed in Japan.[Washington Post (5 January 2011)]
Accessed 6 January 2011 Bluefin tuna sashimi is a particular delicacy in Japan. For example, an Atlantic bluefin caught off eastern United States sold for US$247,000 at the Tsukiji fish market
is a major tourist attraction for both domestic and overseas visitors in Tokyo.
The area contains retail markets, restaurants, and associated restaurant supply stores. Before 2018, it was the largest wholesale fish and seafood market in the wor ...
in Tokyo in 2008.[NBC News (1 January 2009)]
Premium tuna fetches $100,000 at auction.
Accessed 6 January 2011 This high price is considerably less than the highest prices paid for Pacific bluefin.[ Prices were highest in the late 1970s and 1980s.
Japanese began eating tuna sushi in the 1840s, when a large catch came into Edo ld Tokyoone season. A chef marinated a few pieces in soy sauce and served it as ''nigiri sushi''. At that time, these fish were nicknamed'' shibi'' — "four days" — because chefs would bury them for four days to mellow their bloody taste.][
By the 1930s, tuna sushi was commonplace in Japan.
]
See also
* Natal homing
Natal homing, or natal philopatry, is the homing process by which some adult animals return to their birthplace to reproduce. This process is primarily used by aquatic animals, such as sea turtles and Pacific salmon. Scientists believe that the m ...
References
Further reading
* Clover, Charles (2004). '' The End of the Line: How Overfishing Is Changing the World and What We Eat''. Ebury Press, London.
* Hogan, C. Michael. (2010)
"Overfishing"
''Encyclopedia of Earth''. National Council for Science and the Environment. eds. Sidney Draggan & C. Cleveland. Washington DC.
* Newlands, Nathaniel K. (2002)
"Shoaling dynamics and abundance estimation: Atlantic bluefin tuna (''Thunnus thynnus'')
. PhD thesis, Resource Management and Environmental Studies/Fisheries Centre, University of British Columbia, Vancouver, Canada. 602pp,
*Newlands, N. K.; Lutcavage, M. & Pitcher, T. (October 2006)
"Atlantic Bluefin Tuna in the Gulf of Maine, I: Estimation of Seasonal Abundance Accounting for Movement, School and School-Aggregation Behaviour"
''Environmental Biology of Fishes''. 77 (2).
*Newlands, N. K.; Lutcavage, M. & Pitcher, T. (December 2007)
"Atlantic bluefin tuna in the Gulf of Maine, II: precision of sampling designs in estimating seasonal abundance accounting for tuna behaviour"
''Environmental Biology of Fishes''. 80 (4): 405–420.
*Newlands, Nathaniel K.; Lutcavage, Molly E. & Pitcher, Tony J. (April 2004)
"Analysis of foraging movements of Atlantic bluefin tuna (''Thunnus thynnus''): individuals switch between two modes of search behaviour"
''Population Ecology''. 46 (1): 39–53.
* Newlands, Nathaniel K.; Porcelli, Tracy A. (2008)
"Measurement of the size, shape and structure of Atlantic bluefin tuna schools in the open ocean"
''Fisheries Research''. 91 (1): 42–55.
* Safina, C. (1993). "Bluefin Tuna in the West Atlantic: Negligent Management, and the Making of an Endangered Species". ''Conservation Biology''. 7: 229–234.
* Safina, C. (1998). ''Song For The Blue Ocean''. Henry Holt Co. New York.
* Safina, C. & Klinger, D. (2008). "Collapse of Bluefin Tuna in the Western Atlantic". ''Conservation Biology''. 22: 243–246.
*
External links
*
Bye bye bluefin: Managed to death
The Economist. 30 October 2008. Retrieved 2009-02-06.
Bluefin Tuna
a
Seafood Watch
Tuna
a
Greenpeace
MarineBio article on tuna
a
MarineBio
brochure on bluefin tuna tagging
a
Tag-a-Giant Foundation
{{Taxonbar , from=Q214415
Commercial fish
Thunnus
Fish described in 1758
Fish of the Dominican Republic
Fish of the Caribbean
Taxa named by Carl Linnaeus
Articles containing video clips