Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
Bluefin trevally
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 centimetres (46 in) and a weight of 43.5 kilograms (96 lb), however is rare above 80 centimetres (31 in). 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.
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, which in turn is part of the order Carangiformes.
The species was first scientifically described by the famed French naturalist Georges Cuvier in 1833 based on specimens collected off Waigeo, 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 has not been included in any detailed phylogenetic studies of the Carangidae.[citation needed]
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.
The bluefin trevally is a large fish, growing to a maximum known length of 117 cm and a weight of 43.5 kg, however it is rare at lengths greater than 80 cm. It is similar in shape to a number of other large jacks and trevallies, having an oblong, compressed body with the dorsal profile slightly more convex than the ventral profile, particularly anteriorly. This slight convexity leads to the species having a much more pointed snout than most other members of Caranx. The dorsal fin is in two parts, the first consisting of 8 spines and the second of 1 spine followed by 21 to 24 soft rays. The anal fin consists of 2 anteriorly detached spines followed by 1 spine and 17 to 20 soft rays. The pelvic fins contain 1 spine and 20 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head. The lateral line has a pronounced and moderately long anterior arch, with the curved section intersecting the straight section below the lobe of the second dorsal fin. The curved section of the lateral line contains 55-70 scales while the straight section contains 0 to 10 scales followed by 27 to 42 strong scutes. The chest is completely covered in scales. The upper jaw contains a series of strong outer canines with an inner band of smaller teeth, while the lower jaw contains a single row of widely spaced conical teeth. The species has 25 to 29 gill rakers in total and there are 24 vertebrae present. The eye is covered by a moderately weakly developed adipose eyelid, and the posterior extremity of the jaw is vertically under or just past the anterior margin of the eye. Despite their wide range, the only geographical variation in the species is the depth of the body in smaller specimens.
The upper body of the bluefin trevally is a silver-brassy colour, fading to silvery white on the underside of the fish, often with blue hues. After they reach lengths greater than 16 cm, blue-black spots appear on the upper flanks of the fish, with these becoming more prolific with age. There is no dark spot on the operculum. The species takes its name from the colour of its dorsal, anal and caudal fins, which are a diagnostic electric blue. The pelvic and pectoral fins are white, with the pectoral fin having a yellow tinge. Juvenile fish do not have the bright blue fins, instead have dark fins with the exception of a yellow pectoral fin. Some juvenile fish have also been recorded as having up to five dark vertical bars on their sides.
The bluefin trevally is widely distributed, occupying the tropical and subtropical waters of the Indian and Pacific Oceans, ranging along the coasts of four continents and hundreds of smaller islands and archipelagos. In the Indian Ocean, the species easternmost range is the coast of continental Africa, being distributed from the southern tip of South Africa north along the east African coastline to the Red Sea and Persian Gulf. The species' range extends eastwards along the Asian coastline including Pakistan, India and into South East Asia, the Indonesian Archipelago and northern Australia. The southernmost record from the west coast of Australia comes from Exmouth Gulf. Elsewhere in the Indian Ocean, the species has been recorded from hundreds of small island groups including the Maldives, Seychelles, Madagascar and the Cocos (Keeling) Islands.
Hub AI
Bluefin trevally AI simulator
(@Bluefin trevally_simulator)
Bluefin trevally
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 centimetres (46 in) and a weight of 43.5 kilograms (96 lb), however is rare above 80 centimetres (31 in). 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.
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, which in turn is part of the order Carangiformes.
The species was first scientifically described by the famed French naturalist Georges Cuvier in 1833 based on specimens collected off Waigeo, 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 has not been included in any detailed phylogenetic studies of the Carangidae.[citation needed]
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.
The bluefin trevally is a large fish, growing to a maximum known length of 117 cm and a weight of 43.5 kg, however it is rare at lengths greater than 80 cm. It is similar in shape to a number of other large jacks and trevallies, having an oblong, compressed body with the dorsal profile slightly more convex than the ventral profile, particularly anteriorly. This slight convexity leads to the species having a much more pointed snout than most other members of Caranx. The dorsal fin is in two parts, the first consisting of 8 spines and the second of 1 spine followed by 21 to 24 soft rays. The anal fin consists of 2 anteriorly detached spines followed by 1 spine and 17 to 20 soft rays. The pelvic fins contain 1 spine and 20 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head. The lateral line has a pronounced and moderately long anterior arch, with the curved section intersecting the straight section below the lobe of the second dorsal fin. The curved section of the lateral line contains 55-70 scales while the straight section contains 0 to 10 scales followed by 27 to 42 strong scutes. The chest is completely covered in scales. The upper jaw contains a series of strong outer canines with an inner band of smaller teeth, while the lower jaw contains a single row of widely spaced conical teeth. The species has 25 to 29 gill rakers in total and there are 24 vertebrae present. The eye is covered by a moderately weakly developed adipose eyelid, and the posterior extremity of the jaw is vertically under or just past the anterior margin of the eye. Despite their wide range, the only geographical variation in the species is the depth of the body in smaller specimens.
The upper body of the bluefin trevally is a silver-brassy colour, fading to silvery white on the underside of the fish, often with blue hues. After they reach lengths greater than 16 cm, blue-black spots appear on the upper flanks of the fish, with these becoming more prolific with age. There is no dark spot on the operculum. The species takes its name from the colour of its dorsal, anal and caudal fins, which are a diagnostic electric blue. The pelvic and pectoral fins are white, with the pectoral fin having a yellow tinge. Juvenile fish do not have the bright blue fins, instead have dark fins with the exception of a yellow pectoral fin. Some juvenile fish have also been recorded as having up to five dark vertical bars on their sides.
The bluefin trevally is widely distributed, occupying the tropical and subtropical waters of the Indian and Pacific Oceans, ranging along the coasts of four continents and hundreds of smaller islands and archipelagos. In the Indian Ocean, the species easternmost range is the coast of continental Africa, being distributed from the southern tip of South Africa north along the east African coastline to the Red Sea and Persian Gulf. The species' range extends eastwards along the Asian coastline including Pakistan, India and into South East Asia, the Indonesian Archipelago and northern Australia. The southernmost record from the west coast of Australia comes from Exmouth Gulf. Elsewhere in the Indian Ocean, the species has been recorded from hundreds of small island groups including the Maldives, Seychelles, Madagascar and the Cocos (Keeling) Islands.