Thunnus orientalisBluefin tuna(Also: Pacific bluefin tuna)

Geographic Range

Pacific bluefin tuna (Thunnus orientalis) inhabit mainly cooler waters of the North Pacific Ocean between a latitude of 45- and 5-degrees north. Some inhabit tropical waters of New Zealand and French Polynesia. Pacific bluefin tunas range from the east Pacific, to the Japanese mainland and its islands, to the western coast of the United States and Canada. (Collette and Smith, 1981; Fujioka, et al., 2017; Kitagawa, et al., 2007)

Habitat

Pacific bluefin tuna generally inhabit the epipelagic region, but will occasionally come close to shore. Because they have tolerance to a wide temperature range (2 to 30°C), individuals can inhabit waters from 0 to 550 m deep. Some migration occurs as seasons change and water temperatures change, as they are mostly found in the waters between 18 to 20°C. In autumn, some travel to the northern shores of California, away from cooler Pacific waters with harsher windstorms. They also migrate further south during winter, as lower water temperatures decrease predator populations. (Collette and Smith, 1981; Collette, et al., 2014)

  • Range depth
    0 to 550 m
    0.00 to 1804.46 ft

Physical Description

Pacific bluefin tuna are the largest of three tuna groups. They have black or dark blue dorsal sides with grayish-green iridescence and silver or gray spots on their bellies. Small yellow "fins" that are edged in black begin behind the second dorsal fin and continue to the tail. They have relatively small pectoral fins, and small eyes relative to other tuna species. They have a homocercal, lunate (crescent-shaped) tail that allows for great speed over long distances.

Adult males and females vary in length from 100 cm to 300 cm. It takes individuals 5 years to mature, generally averaging about 150 cm in length with a weight of around 60 kg. The largest Pacific bluefin tuna recorded reached 450 kg and 300 cm in length. Pacific bluefin tuna never stop growing, but growth slows over time. Males and females have about the same growth rate.

Unlike nearly all other fish, these tuna are endothermic. They have a relatively high metabolic rate: basal metabolic rates are reported to range from 0.235 to 0.498 cm^3 oxygen/hour. This trait allows them to tolerate a wide range of water temperatures.

Kawamura et al. (2003) reported the length of newly-hatched larvae to be 3 mm. They reach 3.9 mm by Day 2, and 4 mm by Day 3. They grow to 5.6 mm by Day 8 and 16 mm by Day 16. At 30 days post-hatching, juvenile Pacific bluefin tuna are 5 cm long. At 1 year old, they reach an average fork length of 58 cm. Fork length is the length of an individual fish from the tip of its snout to the end of its middle caudal fin rays). They reach around 1 m fork length by the end of year 3. (Blank, et al., 2007; Collette, et al., 2014; Ishibashi, et al., 2009; Jen-Chieh, et al., 2017; Kawamura, et al., 2003; National Oceanic and Atmospheric Administration, 2018; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    60 kg
    132.16 lb
  • Average length
    150 cm
    59.06 in
  • Range basal metabolic rate
    0.235 to 0.498 cm3.O2/g/hr

Development

Pacific bluefin tuna spawning typically occurs in the Pacific Ocean, at water temps of 23.5 to 29.5°C. Once hatched, Pacific bluefin tuna juveniles migrate to waters of varying temperature.

The average time for eggs to hatch is about 38 hours (range 22 to 48 hours). On average, the fork length of newly-hatched larvae is between 200 mm and 250 mm. Growth is quick; by the time they reach 1 year of age, they average 58 cm fork length. During years 2 to 3, the development slows down. Pacific bluefin tuna reach an average fork length of 1 m by the end of year 3. Growth occurs mostly between 1 and 3 years, after which the growth rate slows down, eventually hitting steady growth. They grow indeterminately but very slowly by the time they have reached 230 cm in total length. (Partridge, 2013; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017; Tanaka, et al., 2007)

Reproduction

Pacific bluefin tuna spawning occurs similarly to their close relative, Atlantic bluefin tuna (Thunnus thynnus). Egg spawning occurs daily between April to July in the Ryukyu Islands and June to August in the Sea of Japan. The window to late spring into summer months because egg spawning is temperature-sensitive, requiring water temperatures of 23.5 to 29.5°C. Like most bony fish, fertilization occurs externally. Mating can occur between more than one female or male, as these fish are polygynandrous. (Chen, et al., 2006; Kitagawa, et al., 2013; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

Pacific bluefin tuna have temperature-sensitive eggs so spawning is limited to April to July in Ryukyu Islands and June to August in the Sea of Japan. During these periods, individuals can spawn daily. Depending on the size and the age of females, individuals can lay between 780,000 to 35 million eggs per clutch. Larger females lay significantly more eggs than smaller females. The high end of collected egg counts corresponded to a female that was 220 cm long.

The average time for eggs to hatch is about 38 hours (range 22 to 48 hours). Young are independent from birth swim alone or in schools. Sexual maturity varies from 3 to 9 years, but males and females typically reach maturation at age 5. There is a record of individuals staying sexually active for a very long time; the oldest sexually mature individual recorded was 26 years old. (Partridge, 2013; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

  • Breeding interval
    Spawning occurs daily from April to August
  • Breeding season
    April to July in Ryukyu Islands and June to August in the Sea of Japan
  • Range number of offspring
    780000 eggs to 35000000 eggs
  • Range time to hatching
    26 to 48 hours
  • Average time to hatching
    38 hours
  • Range time to independence
    0 to 0 years
  • Range age at sexual or reproductive maturity (female)
    3 to 9 years
  • Average age at sexual or reproductive maturity (female)
    5 years
  • Range age at sexual or reproductive maturity (male)
    3 to 9 years
  • Average age at sexual or reproductive maturity (male)
    5 years

The egg has nutrition to sustain adequate larvae development. Swimming to designated spawning areas takes energy from both sexes, but beyond the act of mating, males and females exhibit no parental investment. ("Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning

Lifespan/Longevity

In the wild, Pacific bluefin tuna are expected to live to about 15 years, but the longest lifespan recorded is 26 years. These tuna do not live in captivity for long periods of time; captive fisheries take animals from the wild and only keep them for short times to allow growth before re-release. Hatcheries do keep a few adults for spawning purposes. In both cases, the tuna are not kept long-term. ("Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017; Tamaki, et al., 2009)

  • Range lifespan
    Status: wild
    26 (high) years
  • Average lifespan
    Status: wild
    15 years

Behavior

Pacific bluefin tuna tend to swim in schools with other tuna, including closely-related species like Atlantic bluefin tuna (T. thynnus) and southern bluefin tuna (T. maccoyii).

Pacific bluefin tuna migrate seasonally due to water temperature changes. Between June and August, when waters are warmer they migrate to breeding waters just west of Japan or between Japan and the Philippines. Some juveniles stay in the western Pacific; others, at about a year of age, migrate either south to Australia or east to the west coast of the United States. They remain in these areas (moving north and south along the coast of the United States and Mexico) for several years before returning to Japan to spawn. NOAA estimated the time to migrate from the U.S. western coast back to Japan (about 8,000 km) as 55 days (or more; Boustany et al., 2010 reported a trip time of 66 days), and possibly more than half of those fish between 1 and 3 years will survive this trip. They tolerate water temperatures as low as 9°C during this migration.

Migration is highly dependent on food availability and water temperature. In order to swim to designated places, they rely on their visual and olfactory senses to guide them. They do not have very good vision, and so they migrate during the day. As they get older, their swimming patterns also change; immediately after they hatch, Pacific bluefin tuna swim closer together and at a faster rate. After 26 to 30 days, tuna speed decreases and space between two schooling fish increases.

As endotherms (an unusual trait for fish), these tuna can tolerate a wide range of water temperatures and exhibit a high cardiac output. They can swim at fast speeds, clocked as high as 48 km/h in short sprints while hunting (generally less than 20 seconds at this speed). Migration distances can average 145 km a day. (Boustany, et al., 2010; Collette and Smith, 1981; Collette, et al., 2014; Fukuda, et al., 2010; Hall, 2017; Ishibashi, et al., 2009; Kitagawa, et al., 2007; National Oceanic and Atmospheric Administration, 2018; Partridge, 2013; Torisawa, et al., 2011)

Home Range

Pacific bluefin tuna are a very mobile fish, perhaps the most mobile of all tuna species. Boustany et al. (2010) used electronic and archival tags to document locations for over 250 tuna. Although home range was not reported for individuals, the authors noted that individuals and populations kept home ranges seasonally, and migrated in schools. They do not actively defend their territory. (Boustany, et al., 2010; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

Communication and Perception

Pacific bluefin tuna use their eyes to locate prey. Egg fertilization occurs externally, so they also rely on vision to locate eggs. Although they have poor vision, their eyes have rods and cones, allowing them to see color and even shades of gray. By the time larvae are 5 days old (ca. 4.5 mm long), they are reported to be photopositive (attracted to light).

Olfactory senses differentiate chemicals in the water, so Pacific bluefin tuna aren’t fully reliant on sight. Taste buds begin to develop in larvae about 10 days after hatching, and are complete by Day 33.

These tuna are endothermic, which, combined with their physical build, allows them to swim at high speeds and catch prey. The ability to see shades of gray gives them an advantage while hunting in areas with low light. They use their sense of touch to locate what is around them and potentially alert about changes in the environment. (Chen, et al., 2006; Collette, et al., 2014; Kawamura, et al., 2003; Kitagawa, et al., 2013; National Oceanic and Atmospheric Administration, 2018; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017; Torisawa, et al., 2011)

Food Habits

Pacific bluefin tuna are opportunistic feeders, meaning they do not have specific feeding patterns and feed based on prey abundance. While they are mostly carnivorous, they also consume algae. Up to a year of age they predominantly consume small squids (Decapodiformes) and zooplankton (such as Daphnia). After about 1 year they start eating a wide range of fish and other algae. They consume anchovies (Engraulidae), jack mackerel (Trachurus symmetricus), Pacific mackerel (Scomber japonicus), lanternfish (Myctophidae nitidulum), Pacific saury (Cololabis saira), rock fish (Sebastes), sardines (Sardina pilchardus), squid (Decapodiformes), crustaceans (Crustacea), and pelagic red crab (Pleuroncodes planipes).

Pinkas et al. (1971) reported that the squid, Abraliopsis felis, comprised 89% of the diet of bluefin tuna in Californian and Mexican waters. Across multiple studies, anchovies and squid were substantial and consistent components of their diet.

In one study, authors reported that the majority of their diet consists of fish. Benoit's lanternfish (Hygophum benoiti) made up a substantial part (about 10.59%) of the diet of Pacific bluefin tuna. The major influencing factor on their diet is range and availability. In some scenarios, when food is limited, aggression towards each other increases. This sometimes leads to small larvae being cannibalized. ("Food Habits of Albacore, Bluefin Tuna, and Bonito in California Waters", 1971; Ishibash, et al., 2014; Karakulak, et al., 2009; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

  • Animal Foods
  • mollusks
  • aquatic crustaceans
  • zooplankton
  • Plant Foods
  • algae

Predation

Predators of Pacific bluefin tuna include killer whales (Orcinus orca), great white sharks (Carcharodon carcharias), mako sharks (Isurus oxyrinchus), and humans (Homo sapiens). Due to their color they can blend with the water and not be easily seen from a distance. Their color patterns provide natural camouflage in the oceanic environment. The juveniles do not get bothered often by their predators, on rare occasions they get mistaken by birds and captured. When tuna are several years old, whale and shark predators have a greater impact on the populations. Humans (Homo sapiens) are responsible for the majority of adult tuna deaths. (Collette, et al., 2014; ; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Pacific bluefin tuna play an important role in their ecosystem. They are considered a large predator, consuming smaller fish, crustaceans, and crabs. They also serve as prey species to other predators, such as killer whales (Orcinus orca), great white sharks (Carcharodon carcharias), mako sharks (Isurus oxyrinchus). Pacific bluefin tuna also provide a substantial food source to human populations (Homo sapiens) around the world.

Pacific bluefin tuna act as hosts for numerous parasites, including myxosporea (a type of parasitic Cnidarian: Kudoa neothunni and Kudoa hexapunctata) and blood flukes (Cardicola orientalis, Cadocicola forsteri, Cardicola ambrosioi and members of the genus, Paradeontacylix). ("Food Habits of Albacore, Bluefin Tuna, and Bonito in California Waters", 1971; Ogawa, et al., 2009)

Commensal/Parasitic Species
  • blood fluke Cardicola orientalis
  • blood fluke Cadocicola forsteri
  • blood fluke Cardicola ambrosioi
  • blood fluke Paradeontacylix
  • Myxosporea Kudoa neothunni
  • Myxosporea Kudoa hexapunctata

Economic Importance for Humans: Positive

Pacific bluefin tuna provide nutrition for humans (Homo sapiens); they are a very popular food worldwide. The highest demand for them is in Japan, where they are traditionally used in sushi. In recent years, Japan has been responsible for the greatest harvest records, accounting for over half the Pacific blue tuna harvest in 2015. Reports from 2014 quantified harvests: Japan harvested more than 9,500 metric tons of Pacific bluefin tuna, followed by Mexico (4,800 mt), Korea (1,311 mt), Taiwan (525 mt), and the United States (408 mt).

These fish are of great importance to the global economy. There are strict rules in place to prevent over-fishing and deterioration of economic growth. Tuna support a multi-billion dollar market, with demand for their meat increasing every year. About $74 million worth of production happens in Baja California, Mexico alone.

These tuna are occasionally used in education and research. Most of this is related directly to harvest efforts. Studies in migration and feeding (sometimes by stable isotope analyses) have been reported by Craig et al. (2017). (Gwo, et al., 2005; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017; Zertuche-González, et al., 2008)

  • Positive Impacts
  • food
  • research and education

Economic Importance for Humans: Negative

Pacific bluefin tuna have no negative economic impacts on humans. Although they have been reported to carry parasites, and these tuna are consumed raw as sushi, Craig et al. (2017) reported that these parasites have not caused large-scale harm to humans. (; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

Conservation Status

Pacific bluefin tuna have not been given a status on Us Federal List, CITIES or State of Michigan List but are listed as "Vulnerable" on the IUCN Red List. This vulnerable status means they are not endangered yet, but without any protective measures, they will be. NOAA Fisheries (a federal agency) states that these tuna are over-fished, and have proposed a harvest reduction to support sustainable fisheries.

Pacific bluefin tuna are vulnerable to few threats in their own environment. While predation from whales and sharks does occur, the most substantial threat is over-fishing by humans. Craig et al. (2017) reported that harvest peaked in 1956 at over 40,000 metric tons, and averages about half of that today. Because these tuna are harvested both at spawning grounds (in Japan) and non-spawning grounds (e.g. the western coast of the U.S.), international agreements are in place to maintain a sufficient stock for sustainable fisheries. These agreements have not always been followed, and Craig et al. (2017) reported that although there is not a short-term threat to sustainability, this ineffectual international control will affect tuna long term.

Additional threats include climate change and radioactive spills. Climate change is suspected to affect spawning grounds, since they only spawn around Japan and microhabitats there are expected to change. The migratory pathway also may be affected in the long term. After the Fukushima reactor issues in 2011 nearby waters absorbed radioactive materials; these radionuclides have been found in Pacific bluefin tuna in California, showing the migratory connection between these two locations. However, researchers have reported no long-term negative impacts of the spill on these tuna.

Conservation efforts of Pacific bluefin tuna are in place, but are location-specific. Emphasis has been placed on reducing the commercial intake of young (less than 3 years old) bluefin tuna in multiple areas – especially in Japan and Korea. An upper limit of metric tons per year (5,000 in 2014) has been set in Mexico and the United States. Reported catches in the U.S. have been lower in recent years. Only after heading south into waters near Mexico have catch numbers increased. Recreational fishing in California has also been restricted. Since 2015, the catch limit has been reduced from 10 to 2 per day.

Some fish hatchery efforts are in place, but they mostly involve catching tuna in the wild and raising them for a couple years, or they include keeping spawning individuals. There has been an effort to begin cryopreservation of semen, as well.

There are research questions that need to be answered to better manage Pacific bluefin tuna. Finding a better way to assess population numbers (stocks) would help greatly. A better understanding of migratory patterns, feeding habitats, and spawning behaviors is needed as well. Finally, predicting the impacts of climate change on this fish population is an important question, in need of investigation. (Collette, et al., 2014; Gwo, et al., 2005; Matsukawa, 2006; Ottolenghi, 2008; "Status review report of Pacific bluefin tuna (Thunnus orientalis)", 2017)

Contributors

Matt Zbroinski (author), Radford University, Lauren Burroughs (editor), Radford University, Logan Platt (editor), Radford University, Karen Powers (editor), Radford University, Galen Burrell (editor).

Glossary

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

herbivore

An animal that eats mainly plants or parts of plants.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pelagic

An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).

piscivore

an animal that mainly eats fish

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

visual

uses sight to communicate

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

References

California Department of Fish and Game. Food Habits of Albacore, Bluefin Tuna, and Bonito in California Waters. Fish Bulletin 152. San Diego, California: California Department of Fish and Game. 1971. Accessed November 24, 2019 at https://oac.cdlib.org/view?docId=kt8290062w&brand=oac4&doc.view=entire_text.

Pacific Bluefin Tuna Status Review Team (Craig et. al). Status review report of Pacific bluefin tuna (Thunnus orientalis). NOAA-TM-NMFS-SWFSC/587. La Jolla, CA: Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service. 2017. Accessed November 24, 2019 at https://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-587.pdf.

Ashida, H., N. Suzuki, T. Tanab, N. Suzuk, Y. Aonuma. 2014. Reproductive condition, batch fecundity, and spawning fraction of large Pacific bluefin tuna Thunnus orientalis landed at Ishigaki Island, Okinawa, Japan. Environmental Biology of Fishes, 98/4: 1173–1183.

Biswas, B., S. Ji, A. Biswas, M. Seoka, Y. Kim, K. Kawasaki, K. Takii. 2009. Dietary protein and lipid requirements for the Pacific bluefin tuna Thunnus orientalis juvenile. Aquaculture, 288/1/2: 114-119.

Blank, J., C. Farwell, J. Morrissette, R. Schallert, B. Block. 2007. Influence of Swimming Speed on Metabolic Rates of Juvenile Pacific Bluefin Tuna and Yellowfin Tuna. The University of Chicago Press, 80/2: 167-177.

Boustany, A., R. Matteson, M. Castleton, C. Farwell, B. Block. 2010. Movements of pacific bluefin tuna (Thunnus orientalis) in the Eastern North Pacific revealed with archival tags. Progress in Oceanography, 86/1: 94-104.

Chen, K., P. Crone, C. Hsu. 2006. Reproductive biology of female Pacific bluefin tuna Thunnus orientalis from south-western North Pacific Ocean. Fisheries Science, 72/5: 985-994.

Collette, B., W. Fox, M. Juan Jorda, R. Nelson, D. Pollard, N. Suzuki, S. Teo. 2014. "Pacific bluefin tuna (Thunnus orientalis)" (On-line). The IUCN Red List of Threatened Species 2014: e.T170341A65166749. Accessed September 06, 2019 at http://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T170341A65166749.en.

Collette, B., B. Smith. 1981. Bluefin tuna, Thunnus thynnus orientalis, from the Gulf of Papua. Journal of Ichthyology, 28/2: 166-168.

Fujioka, K., H. Fukuda, S. Furukawa, Y. Tei, S. Okamoto, S. Ohshimo. 2017. Habitat use and movement patterns of small (age-0) juvenile Pacific bluefin tuna (Thunnus orientalis) relative to the Kuroshio. Fisheries Oceanography, 27/3: 185-198.

Fukuda, H., S. Torisawa, Y. Sawada, T. Takagi. 2010. Ontogenetic changes in schooling behaviour during larval and early juvenile stages of Pacific bluefin tuna Thunnus orientalis. Journal of Fish Biology, 76/7: 1841-1847.

Gwo, H., T. Weng, L. Fan, Y. Lee. 2005. Development of cryopreservation procedures for semen of Pacific bluefin tuna Thunnus orientalis. Aquaculture, 249/1-4: 205-211.

Hall, D. 2017. "The great Pacific migration of bluefin tuna" (On-line). Smithsonian National Museum of Natural History. Accessed November 24, 2019 at https://ocean.si.edu/ocean-life/fish/great-pacific-migration-bluefin-tuna.

Ishibash, Y., T. Miki, Y. Sawada, M. Kurata. 2014. Effects of feeding conditions and size differences on aggressive behaviour and cannibalism in the Pacific bluefin tuna Thunnus orientalis (Temminck and Schlegel) larvae. Aquaculture Research, 45/1: 45-53.

Ishibashi, Y., T. Honryo, K. Saida, A. Hagiwara, S. Miyashita, Y. Sawada, T. Okada, M. Kurata. 2009. Artificial lighting prevents high night-time mortality of juvenile Pacific bluefin tuna, Thunnus orientalis, caused by poor scotopic vision. Aquaculture, 293/3: 157-163.

Jen-Chieh, S., L. Han-Bo, H. Jhen, W. Hui-Yu, C. Shui-Kai, H. Min-Yu, I. Taiki. 2017. Changes in size, age, and sex ratio composition of Pacific bluefin tuna (Thunnus orientalis) on the northwestern Pacific Ocean spawning grounds. ICES Journal of Marine Science, 74/1: 204-214.

Jusup, M., T. Klanjscek, H. Matsuda, S. Kooijman. 2011. A full lifecycle bioenergetic model for bluefin tuna. PLoS ONE, 6/7: e21903. Accessed September 06, 2019 at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0021903.

Karakulak, F., A. Salman, I. Oray. 2009. Diet composition of bluefin tuna ( Thunnus thynnus L. 1758) in the Eastern Mediterranean Sea, Turkey. Journal of Applied Ichthyology, 25/6: 757-761.

Kawamura, G., S. Masuma, N. Tezuka, M. Koiso, T. Jinbo, K. Namba. 2003. Morphogenesis of sense organs in the bluefin tuna Thunnus orientalis. The Big Fish Bang: Proceedings of the 26th Annual Larval Fish Conference. Edited by Howard I. Browman and Anne Berit Skiftesvik, None: 123-135. Accessed November 24, 2019 at http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.294.6822&rep=rep1&type=pdf.

Kitagawa, T., A. Boustany, C. Farwell, T. Williams, M. Castleton, B. Block. 2007. Horizontal and vertical movements of juvenile bluefin tuna (Thunnus orientalis) in relation to seasons and oceanographic conditions in the eastern Pacific Ocean. Fisheries Oceanography, 16/5: 409-421.

Kitagawa, T., T. Ishimura, R. Uozato, K. Shirai, Y. Amano, A. Shinoda, T. Otake, U. Tsunogai, S. Kimura. 2013. Otolith δ18O of Pacific bluefin tuna Thunnus orientalis as an indicator of ambient water temperature. Marine Ecology Progress Series, 481: 199-209.

Komeyama, K., M. Kadota, S. Torisawa, T. Takagi. 2013. Three-dimensional trajectories of cultivated Pacific bluefin tuna Thunnus orientalis in an aquaculture net cage. Aquaculture Environment Interactions, 4/1: 81-90.

Matsukawa, Y. 2006. Carrying capacity and survival strategy for the Pacific bluefintuna,Thunnus orientalis, in the Western Pacific. Fisheries Oceanography, 15/2: 104-112.

Nakagawa, Y., M. Eguchi, S. Miyashita. 2007. Pacific bluefin tuna, Thunnus orientalis, larvae utilize energy and nutrients of microbial loop. Aquaculture, 267/1: 83-93.

National Oceanic and Atmospheric Administration, 2018. "Pacific Bluefin Tuna (Thunnus orientalis)" (On-line). Accessed November 22, 2019 at https://www.fisheries.noaa.gov/species/pacific-bluefin-tuna.

Ogawa, K., S. Tanaka, Y. Sugihara, I. Takami. 2009. A new blood fluke of the genus Cardicola (Trematoda Sanguinicolidae ) from Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel, 1844 ) cultured in Japan. Elsevier, 59/1: 44-48.

Ottolenghi, F. 2008. Capture-based aquaculture of bluefin tuna. Fisheries Technical Paper., 508: 169-182.

Pardo, J., F. Vergara‐Solana, M. Araneda‐Padilla, S. Ortega‐García, J. Carlos Seijo, G. Ponce‐Díaz. 2019. Growth and survival model of Pacific bluefin tuna (Thunnus orientalis) for capture‐based aquaculture in Mexico. Aquaculture Research, 0/0: 1-10.

Partridge, G. 2013. Closed-cycle hatchery production of tuna. Pp. 457-497 in Advances in Aquaculture Hatchery Technology, Vol. 242. Oxford, England: Elsevier.

Qiu, F., M. Miyamoto. 2011. Use of nuclear DNA data to estimate genetic diversity and population size in Pacific bluefin and yellowfin tuna (Thunnus orientalis and T. albacares). Copeia, 2011/2: 264-269.

Runcie, R., B. Muhling, E. Hazen, S. Bograd, T. Garfield, G. DiNardo. 2019. Environmental associations of Pacific bluefin tuna (Thunnus orientalis) catch in the California Current system. Fisheries Oceanography, 28/4: 372-388.

Shimose, T., H. Watanabe, T. Tanabe, T. Kubodera. 2013. Ontogenetic diet shift of age-0 year Pacific bluefin tuna Thunnus orientali. Journal of Fish Biology, 82/1: 263-276.

Shimose, T., Y. Aonuma, N. Suzuki, T. Tanabe. 2016. Sexual differences in the occurrence of Pacific bluefin tuna Thunnus orientalis in the spawning ground, Yaeyama Islands. Environmental Biology of Fishes, 99/4: 351-360.

Stein, M., D. Margulies, J. Wexler, V. Scholey, K. Ryo, T. Honryo, T. Sasaki, A. Guillen, Y. Agawa, Y. Sawada. 2018. A comparison of the effects of two prey enrichment media on growth and survival of Pacific bluefin tuna, Thunnus orientalis, larvae. Journal of the World Aquaculture Society, 49/1: 240-255.

Tamaki, S., T. Toshiyuki, C. Kuo-Shu, H. Chien-Chung. 2009. Age determination and growth of Pacific bluefin tuna, Thunnus orientalis, off Japan and Taiwan. Fisheries Research, 100/2: 134-139.

Tanaka, Y., M. Mohri, H. Yamada. 2007. Distribution,growth and hatch date of juvenile Pacific bluefin tuna Thunnus orientalis in the coastal area of the Sea of Japan. Fisheries Science, 73/3: 534-542.

Torisawa, S., H. Fukuda, K. Suzuki, T. Tagaki. 2011. Schooling behaviour of juvenile Pacific bluefin tuna Thunnus orientalis depends on their vision development. Journal of Fish Biology, 79/5: 1291-1303.

Yokoyama, H., J. Suzuki, S. Shirakashi. 2014. Kudoa hexapunctata n. sp. (Myxozoa: Multivalvulida) from the somatic muscle of Pacific bluefin tuna Thunnus orientalis and re-description of K. neothunni in yellowfin tuna T. albacares. Parasitology International, 63/4: 571-579.

Zertuche-González, J., O. Sosa-Nishizaki, J. Vaca-Rodríguez, R. Del Moral, C. Yarish, B. Costa-Pierce. 2008. Marine science assessment of capture-based tuna (Thunnus orientalis) aquaculture in the Ensenada Region of northern Baja California, Mexico. Open Publication - Connecticut University, None: 1-95. Accessed November 22, 2019 at https://opencommons.uconn.edu/cgi/viewcontent.cgi?article=1000&context=ecostam_pubs.