Bludger | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Carangiformes |
Family: | Carangidae |
Genus: | Carangoides |
Species: | C. gymnostethus |
Binomial name | |
Carangoides gymnostethus (G. Cuvier, 1833) | |
Approximate range of the bludger | |
Synonyms | |
The bludger (Carangoides gymnostethus), also known as the bludger trevally, nakedbreast trevally or Bleeker's jackfish, is a widespread species of large marine fish in the jack family, Carangidae. The bludger inhabits the tropical and subtropical regions of the Indo-west Pacific Ocean, distributed from South Africa in the west to Japan and New Caledonia in the east. It is a large fish, growing to a maximum recorded length of 90 cm, and is very similar to the yellowspotted trevally, Carangoides fulvoguttatus, but can be separated by the complete absence of breast scales and a number of other anatomical features. The species inhabits moderately deep offshore coral and rocky reefs, where it preys on small crustaceans and fish. The reproductive biology of the species is poorly known, but it appears to move to more tropical waters to spawn. The bludger is of intermediate importance to fisheries throughout its range, taken by hook and line and various netting methods. It is of some value to anglers also, considered a good gamefish, but generally regarded as poor eating due to its soft oily flesh, which is used as bait by many anglers. The name ‘bludger’ is said to either refer to the blunt head of the species, or the destination of the fish when caught by professional fishermen who treat the fish as discard.
The bludger is classified within the genus Carangoides , a group of fish commonly known as jacks and trevallies. Carangoides falls into the jack and horse mackerel family Carangidae, the Carangidae are part of the order Carangiformes. [2]
The species was first scientifically described by the famed French naturalist Georges Cuvier in 1833 based on the holotype specimen taken in the Seychelles. [3] Cuvier named his species Caranx gymnostethus, with the specific epithet meaning 'naked breast' in reference to its scaleless breast. The species was later reassigned to the genus Carangoides, where it has remained since. In 1851, Pieter Bleeker named what he believed to be a new species Carangoides gymnostethoides, which literally translates as 'like Carangoides gymnostethus', indicating its similarity to the bludger. This was later found to be the same as Carangoides gymnostethus and became a junior synonym. [4] Confusion with Carangoides orthogrammus in Hawaiian waters led John Nichols to propose subspecies of Carangoides gymnostethoides due to slight anatomical differences. These taxa possibly represent misidentified C. orthogrammus, although Nichols meticulous distinction of the species may indicate a population of the species may exist in Hawaii, [4] although these subspecies have largely been ignored by taxonomic authorities and remained unresolved. The species has the unusual common name of 'bludger', which is said to have arisen by one of two ways; either due to the blunt shape of the species snout [5] or a description of the eventual destination of the fish when caught by professional fishermen seeking more desirable catches. [6] In both cases, the word 'bludger' refers to an object used to bludgeon.[ citation needed ]
The bludger is a large fish, growing to at least 90 cm in length and reaching a recorded maximum weight of 14.5 kg. [7]
The bludger has a body shape very similar to the yellowspotted trevally, being more elongated and subcylindricall than most of the genus Carangoides. [8] As a juvenile, the fish is ovate, becoming more elongated with age, with the convex dorsal profile of the head and nape becoming less steep with age also. [8] The dorsal fin is in two distinct parts, the first consisting of 8 spines while the second is composed of 1 spines and 28 to 32 soft rays, with the anterior lobe of this fin being shorter than the head length. The anal fin has two anteriorly detached spines followed by 1 spine attached to 24 to 26 soft rays and the pelvic fin has 1 spine and 18 to 20 soft rays. [9] The lateral line has a gentle anterior arch which is slightly longer than the straight section of the lateral line, with the intersection below the sixteenth to twentieth soft ray of the dorsal fin. The curved section contains 78 to 80 scales while the straight section consists of 15 to 19 scales and 21 to 27 scutes. [9] The breast is scaleless until the origin of the pelvic fins and up to the origin of the pectoral fins. In adults, the mouth cleft is level with the eye, with both jaws containing bands of villiform teeth which become wider anteriorly. There are 27 to 31 gill rakers in total and 25 vertebrae. [8]
The bludger has an overall silver-green body as a juvenile, while adults have green-blue to olive green body above, becoming more silvery below. [10] At all stages of its life, the fish has a few brown or golden spots in a midlateral band, but much less than the yellowspotted trevally, while the dusky opercular spot is often inconspicuous. The dorsal, anal and caudal fins are olive green, with the soft dorsal, anal and anal fins having white lobe tips and the anal having white leading and distal edge. The pelvic and pectoral fins are hyaline to green. [10]
The bludger is distributed throughout the tropical to subtropical regions of the Indian and west Pacific Oceans, [11] ranging from South Africa in the west, along east Africa and north to the Red Sea. Its distribution in the Indian Ocean extends east to India, South East Asia, Indonesia and as far south as northern Australia. In the Pacific Ocean, it extends as far north as Japan and out to New Caledonia, Tonga and the Kapingamarangi Atoll. [7]
The bludger inhabits moderately deep offshore waters on rocky and coral reef structures, rarely found in inshore waters. [5]
The bludger moves in small schools as a juvenile, becoming more solitary with age. The species has a rather soft mouth and weak jaws, limiting the types of prey available to it, with studies showing prawns, small crabs, mantis shrimps and small fish are its main prey. [5] Research on the North West Shelf of Australia indicates there is diet partitioning between the bludger and the yellowspotted trevally, with the bludger taking mostly crustaceans while the yellowspotted trevally consumes mostly fish and cephalopods. [10] The species itself is known to be prey for sharks including the blacktip shark, Carcharhinus tilstoni . [12] Reproduction and growth in the species is poorly studied, with preliminary observations in South Africa indicating the fish may move from this region to more tropical waters of Mozambique to spawn. [5]
The bludger is of minor importance to fisheries throughout its range, taken by hook and line as well as gill nets and various types of fish trap. [8] Separate catch statistics are not kept for the species, as it is often not distinguished from other trevallies. The bludger is also of some interest to anglers, although the level of interest differs between countries. In South Africa it is considered a good catch by boat anglers and spearfishermen and is generally regarded as high quality table fare. [5] In Australia it is still considered a good gamefish, but of a lower caliber than related species such as giant and bluefin trevally, and is regarded as a poor table fish. Its soft, oily flesh is often used for bait when reef fishing. It may be caught using small baits or lures. [6]
The bigeye trevally, also known as the bigeye jack, great trevally, six-banded trevally and dusky jack, is a species of widespread large marine fish classified in the jack family Carangidae. The bigeye trevally is distributed throughout the tropical waters of the Indian and Pacific Oceans, ranging from South Africa in the west to California and Ecuador in the east, including Australia to the south and Japan in the north. The bigeye trevally is best distinguished by its colouration, having a dark second dorsal fin with a white tip on the lobe, and also possessing a small dark spot on the operculum. Other more detailed anatomical features also set the species apart from other members of Caranx. The species is known to grow to a length of 120 cm and 18 kg.
The Malabar trevally, also known as the Malabar jack, Malabar kingfish or nakedshield kingfish, is a species of large inshore marine fish of the jack family, Carangidae. It is distributed throughout the Indian and west Pacific Oceans from South Africa in the west to Japan and Australia in the east, inhabiting reefs and sandy bays on the continental shelf. The Malabar trevally is similar to many of the other species in the genus Carangoides, with the number of gill rakers and the grey-brown colour of the tongue being the diagnostic features. The Malabar trevally is a predator, taking a variety of small fish, cephalopods and crustaceans. The species is of minor economic importance throughout its range, caught by a variety of net and handline methods.
The longfin trevally, also known as the longfin kingfish, longfin cavalla or armed trevally, is a species of inshore marine fish in the jack family, Carangidae. The species is common in tropical to subtropical waters of the Indo-Pacific, ranging from South Africa in the west to Japan in the east, typically inhabiting inshore reefs and bays. The species is easily distinguished by its elongate dorsal and anal fin lobes and filamentous dorsal rays, as well as its scaleless breast. Longfin trevally are pelagic predators, taking a variety of small fish, cephalopods and crustaceans, and reach sexual maturity at around 21 cm. The species has a maximum known length of 57 cm and weight of 3.5 kg. The longfin trevally has a very complex taxonomic history which is closely intertwined with another currently valid species, Carangoides ciliarius, which may yet prove to be synonymous. Longfin trevally are of minor importance to fisheries throughout their range and are considered good table fish, and are occasionally taken by anglers.
The longnose trevally, also known as the tea-leaf trevally, club-nosed trevally, grunting trevally or dusky trevally, is a species of inshore marine fish in the jack family, Carangidae. The species is distributed throughout the tropical and subtropical waters of the Indian and west Pacific Oceans from South Africa to New Zealand and Japan, inhabiting coastal waters, especially reefs, to a depth of 90 m. The longnose trevally is distinguished from similar species by a combination of a scaleless breast and the number of gill rakers and fin rays. It is a moderately large fish, growing to a maximum known length of 72 cm and 4.35 kg. The longnose trevally is a predatory fish, consuming small fish, crustaceans and molluscs. The species is of minor commercial importance throughout its range, and is considered to be a good table fish.
The coastal trevally, also known as the onion trevally, Japanese trevally or bluefin kingfish, is a species of inshore marine fish in the jack family Carangidae. The species is distributed throughout the tropical and subtropical waters of the Indian and west Pacific Oceans, from South Africa in the west to Japan and New Caledonia in the east, reaching as far south as Australia. The species is found on deep coastal reefs, both in schools and as solitary individuals, where they prey on small midwater organisms including crustaceans, small fish and cephalopods. The species is taken as bycatch in a number of fisheries throughout its range by a number of fishing methods and is of little commercial value, but is considered to be a good table fish. A mistype in the original volume in which Eduard Rüppell named the species led to the combination Carangoides caeruleopinnatus, which has incorrectly spread through the literature.
The shadow trevally, also known as the shadow kingfish, twothread trevally or Aldabra trevally, is a species of inshore marine fish in the jack family Carangidae. The species is patchily distributed throughout the tropical and subtropical waters of the Indian and west Pacific Oceans, from South Africa in the west to Japan and Samoa in the east, reaching as far south as Indonesia and New Caledonia. It is most easily distinguished from similar species by as series of dark rectangular blotches under the second dorsal fin, giving a 'shadowed' appearance, from which its common name is derived. The shadow trevally is a reasonably large fish, growing to 85 cm in length and at least 2.6 kg in weight. It inhabits shallow coastal waters, including reefs, bays, and estuaries, where it takes small fish and benthic crustaceans as prey. Nothing is known of the species' ecology and reproductive biology. It is of little importance to fisheries, and is occasionally taken by bottom trawls and other artisanal fishing gear.
The threadfin jack or thread pompano is a species of coastal marine fish in the jack family Carangidae. The species inhabits the tropical waters of the eastern Pacific Ocean from Baja California in the north to Ecuador and the Galapagos Islands in the south. It is a moderately large fish, growing to 60 cm (24 in) and may be recognized by its filamentous dorsal and anal fin lobes. The threadfin jack inhabits both deeper coastal waters and inshore environments, including reefs and estuaries, where it preys on minute benthic and pelagic organisms, including small fishes and crustaceans. Very little is known about the ecology and reproductive cycle in the species. The threadfin jack is of importance to fisheries throughout its distribution, caught by hook-and-line and net methods and marketed fresh and salted, and is considered a very good table fish. The species was named Carangoides dorsalis by Theodore Gill 20 years before the name Caranx otrynter was introduced, but confusion with Vomer dorsalis led to the proposal of the new name to separate the two species.
Caranx is a genus of tropical to subtropical marine fishes in the jack family Carangidae, commonly known as jacks, trevallies and kingfishes. They are moderate- to large-sized, deep-bodied fishes which are distinguished from other carangid genera by specific gill raker, fin ray and dentition characteristics. The genus is represented in the Pacific, Indian and Atlantic Oceans, inhabiting both inshore and offshore regions, ranging from estuaries and bays to deep reefs and offshore islands. All species are powerful predators, taking a variety of fish, crustaceans and cephalopods, while they in turn are prey to larger pelagic fishes and sharks. A number of fish in the genus have a reputation as powerful gamefish and are highly sought by anglers. They often make up high amounts of the catch in various fisheries, but are generally considered poor to fair table fishes.
The whitefin trevally, also known as the horse trevally, is a species of deep water offshore fish in the jack family Carangidae. The species inhabits the tropical to temperate waters of the Indo-Pacific and central Pacific, ranging from South Africa in the west to Hawaii in the east. The whitefin trevally is a moderate-sized fish, growing to 37 cm, and is distinguished by a number of morphological traits, including fin size, gill raker count, and colour. It inhabits the continental shelf and slope at depths to 200 m over sand and mud substrates, where it preys on fish, crustaceans, and cephalopods. Studies in Japan indicate a length at sexual maturity of 17.4 cm on average, with spawning occurring between May and October, with each individual spawning multiple times. Whitefin trevallies are of high importance to fisheries in Japan, where they are taken by trawlers, although the catch numbers have halved since the 1980s. It is of minor importance elsewhere throughout its range, but is considered a good table fish.
The blue trevally, also known as the banded trevally, barred trevally, Ferdau's trevally or Forskaal's jackfish, is a common, widespread species of pelagic marine fish classified in the jack family, Carangidae. The blue trevally is distributed throughout the tropical and subtropical waters of the Indo-Pacific and central Pacific regions, ranging from South Africa in the west to Hawaii in the east. It is a moderately large fish, growing to a recorded maximum length of 70 cm, with the number of rays in the second dorsal fin and the colouring serving as diagnostic features of the species. The species inhabits waters to depths of 60 m, generally inhabiting reefs, beaches, lagoons, and areas with sandy substrates. It is a predatory fish, taking other fish, prawns, crabs, and molluscs, and very little is known of the species' reproductive biology. The blue trevally is of varying importance to fisheries throughout its range, with some regions having high catches of the fish. It is considered to be a gamefish, and is sought after for its excellent eating qualities.
The yellowspotted trevally, also known as the yellowspotted kingfish, goldspotted trevally, tarrum, or yellowspot, is a widespread species of large inshore marine fish in the jack family Carangidae. The yellowspotted trevally inhabits the tropical and subtropical waters of the western Indo-Pacific region, from South Africa in the west to Japan and Australia in the east. The species is known to grow to a maximum length of at least 1.2 m, and is distinguished by gill raker and fin morphology, as well as the distinctive golden spots which give the fish its name. The yellowspotted trevally generally prefers inshore rocky and coral reefs, but is occasionally found over deep offshore sand banks to a depth of 100 m. It is a predatory fish, taking fish, cephalopods, and crustaceans, and shows diet partitioning with other trevallies in studies conducted in Australian waters. Reproduction is poorly studied, although observational evidence suggests spawning occurs in aggregations, probably during summer in South Africa. It is generally of minor importance to commercial fisheries throughout its range, but is considered an excellent sportfish by anglers and spearfishermen, and a good table fish.
The bumpnose trevally, also known as the bumpnose kingfish or onion kingfish, is a species of relatively small inshore marine fish classified in the jack family Carangidae. The bumpnose trevally is fairly common in the tropical and subtropical waters of the Indo-west Pacific region, ranging from South Africa in the west to Japan and Samoa in the east. It is a small species by carangid standards, reaching a maximum known length of 32 cm, and can be distinguished from the similarly shaped Carangoides armatus by a distinct 'bump' on the snout, which gives the fish its common name. The species inhabits coastal waters, often living along bays and beaches, where it takes shrimp, small crabs, and juvenile fish as prey. The bumpnose trevally is of minor importance to fisheries throughout its range, taken by hook and line, trawls, and seine nets. It is also of minor importance to anglers, taken by baits from beaches and piers, and is considered a modest table fish.
The duskyshoulder trevally or epaulet trevally, is a species of small inshore marine fish in the jack family, Carangidae. It is distributed through the eastern Indian and western Pacific Oceans, ranging from eastern India to northern Australia and Taiwan. It is relatively small by carangid standards, reaching only 27 cm maximum length, and can be distinguished by the large, black blotches on its shoulders. The duskyshoulder trevally is an inshore fish living in waters less than 50 m deep, over sandy substrates in bays and on the continental shelf. It is a predatory fish, taking demersal fishes, crustaceans, and cephalopods, with nothing known of its reproductive habits. It is of little value to fisheries, often taken as bycatch in prawn trawling operations.
The coachwhip trevally, also known as the oblong trevally or oblique-banded trevally, is a species of inshore marine fish classified in the jack family Carangidae. The coachwhip trevally is distributed through the Indo-west Pacific region, ranging from South Africa in the west to Fiji and Japan in the east. It is a moderately large fish, growing to a known maximum length of 46 cm and can be distinguished from similar species by an array of detailed morphological features including dentition, fin ray counts and scale patterns. The coachwhip trevally inhabits coastal waters throughout its range, known to prefer estuarine waters in a number of localities. Nothing is known of its diet or reproductive biology, and is of little importance to fisheries, occasionally taken as bycatch in trawl and hook and line fisheries.
The island trevally, island jack, thicklip trevally or false bluefin trevally is a widespread species of offshore marine fish classified in the jack family Carangidae. The island trevally is common through the tropical regions of the Indian and Pacific Oceans, ranging from Mozambique and the Seychelles in the west to Hawaii and the Revillagigedo Islands in the central and eastern Pacific. The species is almost completely absent from the continental shelves, instead inhabiting offshore islands, where it is found in lagoons and on reef systems. It is a moderately large fish, growing to a maximum recorded length of 75 cm and 6.6 kg in weight, and is distinguishable by its angular snout and yellow spots, as well as more detailed anatomical features. The island trevally often moves in small schools, preying on a variety of small fishes and crustaceans. It is of moderate importance to fisheries throughout its range, often taken by trawls, hook-and-line, and various inshore netting methods, and is sold fresh or salted at market.
The barcheek trevally, also known as the barcheek kingfish, shortridge trevally or oblique-banded trevally, is a species of moderately large marine fish of the jack family Carangidae. The barcheek trevally is distributed throughout the tropical waters of the Indo-west Pacific region, ranging from South Africa in the west to Japan, Australia and a number of small central Pacific islands in the east. The species inhabits inshore and offshore waters, found along the slopes of lagoons and out to deeper reefs on the continental shelf, where it preys on small fish and benthic crustaceans. It is a moderately large fish, growing to a maximum recorded length of 50 cm, and can be distinguished from similar species by its somewhat protruding lower jaw and the dark banding on its operculum. It is of minor importance to fisheries throughout its range, taken by trawling, hook and line methods and various inshore fish netting methods.
The brownback trevally, also known as the brown-backed trevally, is a species of small inshore marine fish classified in the jack family, Carangidae. The brownback trevally is distributed in two populations through the tropical waters of the Indo-west Pacific region, ranging from the Persian Gulf east to India, South East Asia and the Indonesian islands. The species is distinguished from similar species by its completely scaled breast and black-tipped second dorsal fin, and is known to reach a maximum length of 25 cm. The brownback trevally inhabits inshore waters including bays and estuaries, where it preys on demersal crustaceans and small fish. Other aspects of its biology are poorly known, and it is of minor importance to fisheries, occasionally caught by hook and line or trawls. William Smith-Vaniz has recently suggested the two distinct populations may actually represent two distinct species.
The imposter trevally, also known as the imposter jack or white-tongued trevally, is a species of small coastal marine fish in the jack family Carangidae. The imposter trevally is distributed through the tropical waters of Indian and west Pacific oceans, from the Gulf of Oman in the west to Japan and Australia in the east. The species is quite similar to the Malabar trevally, but can be distinguished by its gill raker count, and is identifiable from other species by having a white to pale grey tongue. It is a relatively small species, growing to a maximum recorded length of 30 cm. The imposter trevally inhabits coastal waters of the continental shelf in depths of up to 140 m, often associating with closely related carangid species. It preys on a range of small fish, crustaceans and cephalopods, but little is known of its reproductive biology. The imposter trevally is of minor importance to fisheries throughout its range, taken by hook and line, bottom trawls and several types of artisanal gear.
The brassy trevally, Caranx papuensis is a species of large marine fish classified in the jack family, Carangidae.
The tille trevally, also known as the tille kingfish, is a species of large marine fish classified in the jack family, Carangidae. The tille trevally is distributed through the tropical and subtropical waters of the Indo-Pacific region, ranging from South Africa in the west to Fiji, Japan and Australia in the east. The species is best distinguished by its rounded, strongly convex anterior profile, with other detailed anatomical features also useful. The tille trevally reaches a maximum length of 80 cm and a weight of 7.2 kg. It is predominantly an inshore species, inhabiting coastal reef and lagoon environments, although has been recorded on deep offshore seamounts. It is a predatory fish, taking various species of fish and crustaceans as prey, with little known of its reproductive cycle. It is of minor importance to fisheries throughout its range, taken by hook and line, gill nets and purse seines. The tille trevally is also considered a good game fish, and an excellent table fish. The species acquired its scientific and common names from a local name used by Pondicherry fishermen, koton tille, which Georges Cuvier then used when he named the species in 1833.
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