On this Wikipedia the language links are at the top tuna loin the page across from the article title. For other uses, see Las Tunas.

Tuna, opah and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. Found in warm seas, the tuna is commercially fished extensively as a food fish, and is popular as a bluewater game fish. The cladogram is a tool for visualizing and comparing the evolutionary relationships between taxa, 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. 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.

The Thunnini tribe also includes seven additional species of tuna across four genera. Bigeye tuna Thunnus obesus showing finlets and keels. The tuna is a sleek and streamlined fish, adapted for speed. The tuna’s body is countershaded to camouflage itself in deeper water when seen from above, its dorsal side is generally a metallic dark blue while the ventral or under side is silvery or whitish. Tunas achieve endothermy by conserving the heat generated through normal metabolism. In all tunas, the heart operates at ambient temperature, as it receives cooled blood, and coronary circulation is directly from the gills. 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. For powerful swimming animals like dolphins and tuna, cavitation may be detrimental, because it limits their maximum swimming speed. 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. This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Tuna is an important commercial fish.

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. Such overfishing has severely damaged bluefin stocks. In recent years, opening day fish auctions at Tokyo’s Tsukiji fish market and Toyosu Market have seen record-setting prices for bluefin tuna, reflecting market demand. 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. Besides for edible purposes, many tuna species are caught frequently as game, often for recreation or for contests in which money is awarded based on weight.

Larger specimens are notorious for putting up a fight while hooked, and have been known to injure people who try to catch them, as well as damage their equipment. Phoenician technique for trapping and catching Atlantic bluefin tuna called Almadraba, still used today in Portugal, Spain, Morocco and Italy which uses a maze of nets. In Sicily, the same method is called Tonnara. 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. 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.

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. The nets were prone to entangling dolphins, injuring or killing them. Fishery practices have changed to be dolphin friendly, which has caused greater bycatch including sharks, turtles and other oceanic fish. Increasing quantities of high-grade tuna caught at sea are reared in net pens and fed bait fish.

Japan is the biggest tuna consuming nation and is also the leader in tuna farming research. 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. The fresh or frozen flesh of tuna is widely regarded as a delicacy in most areas where it is shipped, being prepared in a variety of ways. When served as a steak, the meat of most species is known for its thickness and tough texture. Various species of tuna are often served raw in Japanese cuisine as sushi or sashimi. For a 2-inch tuna steak, this requires 24 hours.

The fish is then vacuum sealed and frozen. In Japan, color fixation using CO is prohibited. Tuna is canned in edible oils, in brine, in water, and in various sauces. Australia Canned tuna was first produced in Australia in 1903 and quickly became popular. The remaining weight is usually oil or water. United States The product became more plentiful in the United States in the late 1940s. In 1950, 8,500,000 pounds of canned tuna were produced, and the U.

Department of Agriculture classified it as a “plentiful food”. Precooked 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 precooked for prescribed times of 45 minutes to three hours. Light and white In some markets, depending upon the color of the flesh of the tuna species, the can is marked as “light” or “white” meat, with “light” meaning a greyish pink color and “white” meaning a light pink color. Percentages are roughly approximated using US recommendations for adults. See also: Mercury in fish and Got Mercury? Mercury content in tuna can vary widely.

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. 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. The Environmental Protection Agency provides guidelines on how much canned tuna is safe to eat. A January 2008 report revealed 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. Bluefin tuna have been widely accepted as being severely overfished, with some stocks at risk of collapse. 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 five years.