![]() In 2002, they succeeded in breeding them, and in 2007, the process was repeated for a third generation. ![]() Kinki University of Japan first successfully farmed already-hatched bluefin tuna in 1979. Japan is both the biggest consumer and the leader in tuna farming research. Pacific bluefin tuna support a large commercial fishery. Human interaction Commercial fishery Pacific bluefin caught near Santa Catalina in 1913 Pacific bluefins eat various small schooling squids and fishes, but have also been recorded taking sessile animals, pelagic red crabs and krill. Large females can carry more eggs than small ones, and between 5 million and 25 million eggs have been reported. Spawning occurs from April to August, but the exact timing depends on the region: Early in the northwest Philippine Sea (the southern part of its breeding range) and late in the Sea of Japan (the northern part of its breeding range). According to the International Game Fish Association, the all-tackle game fish record was a 411.6 kg (907 lb) individual (Donna Pascoe) caught on 19 February 2014 onboard charter boat Gladiator during the National Tournament. Elsewhere, a mass of up to 550 kg (1,210 lb) has been reported for the species. Individuals that are 2 m (6 ft 7 in) long are regularly seen, and the maximum reported is 3 m (9.8 ft) in length and 450 kg (990 lb) in weight. At maturity it is about 1.5 m (4 ft 11 in) long and weighs about 60 kg (130 lb). Pacific bluefin tunas reach maturity at about 5 years of age, the generation length is estimated at 7–9 years and based on two separate sources the longevity is 15 years or 26 years. The additional heat supplied to the muscles is also advantageous because of the resulting extra power and speed. It need not limit its range according to water temperature, nor is it dominated by climatic changes. The tuna's ability to maintain body temperature has several definite advantages over other sea life. Fish from warmer water elevate their temperature a few degrees whereas those from cold water may raise it as much as 20 ☌ (36 ☏) warmer than the surrounding sea. The net effect is less heat loss through the gills. The system acts as a counter-current heat exchanger and the heat from the blood in the veins is given up to the colder arterial blood rather than being lost at the gills. As the warmer blood in the veins returns to the gills for fresh oxygen it comes into close contact with cold, newly oxygenated blood in the arteries. Warm-blooded fish possess organs near their muscles called retia mirabilia that consist of a series of minute parallel veins and arteries that supply and drain the muscles. However, tuna and mackerel sharks are warm-blooded: they can regulate their body temperature. ( December 2011) ( Learn how and when to remove this template message)Īlmost all fish are cold-blooded ( ectothermic). Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources in this section. This section needs additional citations for verification. Physiology At Osaka Aquarium Kaiyukan, Japan The species is considered to consist of only one stock. It has been recorded more locally as a visitor to the Southern Hemisphere, including off Australia, New Zealand, the Gulf of Papua and French Polynesia. Some of these migrate to the East Pacific and return to the spawning grounds after a few years. It spawns in the northwestern Philippine Sea (e.g., off Honshu, Okinawa and Taiwan) and in the Sea of Japan. It typically occurs from the surface to 200 m (660 ft), but has been recorded as deep as 550 m (1,800 ft). It is mainly a pelagic species found in temperate oceans, but it also ranges into the tropics and more coastal regions. The Pacific bluefin tuna is primarily found in the North Pacific, ranging from the East Asian coast to the western coast of North America. Monterey Bay Aquarium's Seafood Watch program have placed all bluefin tunas on the "Avoid" list and they are also placed on the "Red List" by Greenpeace and the Blue Ocean Institute. It is considered threatened by the IUCN and PEW. Like the closely related Atlantic bluefin and southern bluefin, the Pacific bluefin is a commercially valuable species and several thousand tonnes are caught each year, making it overfished. It may reach as much as 3 m (9.8 ft) in length and 450 kg (990 lb) in weight. thynnus is called the Atlantic bluefin tuna). ![]() thynnus, the 'combined' species then known as the northern bluefin tuna (when treated as separate, T. The Pacific bluefin tuna ( Thunnus orientalis) is a predatory species of tuna found widely in the northern Pacific Ocean, but it is migratory and also recorded as a visitor to the south Pacific.
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