Dogtooth tuna

Two fossil species of Gymnosarda are known, suggesting that the genus has existed since the Early Eocene. †Gymnosarda prisca Monsch, 2000 is known from the Early Eocene-aged London Clay of England and the later Eocene-aged deposits of Mangyshlak in Kazakhstan. The remains of this species were previously confused with the co-occurring extinct Spanish mackerel species †Scomberomorus saevus. †Gymnosarda delheidi (Leriche, 1905) is also known from the London Clay, the Early Eocene-aged Nanjemoy Formation of Maryland, US, and the Lutetian-aged Gosport Sand of Alabama, US. This species was previously placed in the genus Sarda. The widespread distribution of Gymnosarda in the Atlantic region during the Eocene, where it is no longer found, contrasts with its present distribution in the Indo-Pacific. Indeterminate fossil remains of Gymnosarda are also known from the Oligocene of Hungary & Romania, and the Late Miocene-aged Bahia Inglesa Formation of Chile. ==Description==

The dogtooth tuna can reach a length of in males and a weight of . The average length commonly observed is around . They have 12 to 14 dorsal soft rays and 12 to 13 anal soft rays. The lateral line undulates strongly. These large tunas have a streamlined shape and a distinctive body coloration: brilliant blue green on the back, silvery on the side, and whitish on the belly, with two white tips on the two back fins close to the caudal peduncle. They always swim with open jaws. The upper jaw of the large mouth reaches the eye. ==Distribution==

The dogtooth tuna is widespread throughout the tropical waters of the Indo-Pacific area from the eastern coast of Africa, Red Sea included, to French Polynesia and oceanic islands of the Pacific Ocean (Hawaii excluded), north to Japan, south to Australia. ==Ecology==

These offshore fishes can be found mainly in reef environments ==Fishing==

These fishes are usually marketed canned and frozen. Adults may be ciguatoxic. These techniques are still often used, with one niche specialty being the use of live bait such as rainbow runners to tease dogtooth tuna within range of light tackle and fly-casting anglers. High speed jigging with a variety of metal lures has increased tremendously in popularity in the last several years as advancements in tackle technology have resulted in lightweight rods and reels that are capable of handling heavy spectra-type braided lines. Some of the more popular destinations for anglers seeking this species include Okinawa and other islands of southern Japan, Rodrigues and other Indian Ocean islands such as the Maldives, Andaman & Nicobar Islands, Bali and elsewhere in Nusa Tenggara in Indonesia, the Great Barrier Reef and its outlying atolls, and many Western Pacific islands such as Vanuatu, Fiji, Tonga, Samoa and Palau. ==References==