|
The bluefin trevally, ''Caranx melampygus'' (also known as the bluefin jack, bluefin kingfish, bluefinned crevalle, blue ulua, omilu and spotted trevally), is a species of large, widely distributed marine fish classified in the jack family, Carangidae. The bluefin trevally is distributed throughout the tropical waters of the Indian and Pacific Oceans, ranging from Eastern Africa in the west to Central America in the east, including Japan in the north and Australia in the south. The species grows to a maximum known length of 117 cm and a weight of 43.5 kg, however is rare above 80 cm. Bluefin trevally are easily recognised by their electric blue fins, tapered snout and numerous blue and black spots on their sides. Juveniles lack these obvious colours, and must be identified by more detailed anatomical features such as fin ray and scute counts. The bluefin trevally inhabits both inshore environments such as bays, lagoons and shallow reefs, as well as deeper offshore reefs, atolls and bomboras. Juveniles prefer shallower, protected waters, even entering estuaries for short periods in some locations. The bluefin trevally is a strong predatory fish, with a diet dominated by fish and supplemented by cephalopods and crustaceans as an adult. Juveniles consume a higher amount of small crustaceans, but transfer to a more fish based diet as they grow. The species displays a wide array of hunting techniques ranging from aggressive midwater attacks, reef ambushes and foraging interactions with other larger species, snapping up any prey items missed by the larger animal. The bluefin trevally reproduces at different periods throughout its range, and reaches sexual maturity at 30–40 cm in length and around 2 years of age. It is a multiple spawner, capable of reproducing up to 8 times per year, releasing up to 6 million eggs per year in captivity. Growth is well studied, with the fish reaching 194 mm in its first year, 340 mm in the second and 456 mm in the third year. The bluefin trevally is a popular target for both commercial and recreational fishermen. Commercial fisheries record up to 50 tonnes of the species taken per year in the west Indian Ocean, and around 700 lbs per year in Hawaii. The rapid decimation of the Hawaiian population due to overfishing has led to increased research in the aquaculture potential of the species, with spawning achieved in captivity. Despite its popularity as a table fish, many cases of ciguatera poisoning have been reported from the species. ==Taxonomy and phylogeny== The bluefin trevally is classified within the genus ''Caranx'', one of a number of groups known as the jacks or trevallies. ''Caranx'' itself is part of the larger jack and horse mackerel family Carangidae, a group of percoid fishes in the order Perciformes. The species was first scientifically described by the famed French naturalist Georges Cuvier in 1833 based on specimens collected off Waigio, Indonesia; one of which was designated to be the holotype. He named the species ''Caranx melampygus'', placing the species in the jack genus ''Caranx'' which had been established by Bernard Lacépède three decades previously. The name's specific epithet is derived from the Latin translation of "black spotted". This is still currently considered the correct placement, however later authors placed in other now defunct genera (''Carangus'' and ''Carangichthys'') which has since been deemed incorrect, and the original classification stands. The species was independently redescribed and named seven times after Cuvier's initial description, with all of these names assigned between 1836 and 1895. The names ''C. bixanthopterus'' and ''C. stellatus'' were often used in the literature, and were variably classed as synonyms of ''C. melampygus'' or valid individual species after their naming. This confusion culminated in Yojiro Wakiya concluding in 1924 they should be treated as separate species. The taxonomy of the species was finally revised by Frederick Berry in 1965, who resolved these two names as being synonymous with ''C. melampygus'', and placed several other names in synonymy with ''C. melampygus''.〔 Under ICZN nomenclature rules, these later names are deemed junior synonyms of ''C. melampygus'' and rendered invalid.〔 The species hat not been included in any detailed phylogenetic studies of the Carangidae. The species is most commonly referred to as the 'bluefin trevally', with the species's distinctive blue fins contributing to most of its other common names. These include bluefin jack, bluefin kingfish, blue ulua, omilu, bluefinned crevalle and spotted trevally. The species has many other non-English names due to its wide distribution. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「bluefin trevally」の詳細全文を読む スポンサード リンク
|