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Black jack (fish)
Encyclopedia
The black jack, Caranx lugubris (also known as the black trevally, black kingfish, coal fish and black ulua), is a species of large marine
fish
in the jack family
Carangidae
. The species has a circumtropical distribution, found in oceanic, offshore waters of the tropical zones of the Pacific, Atlantic and Indian Ocean
s. The species is particularly prevalent around offshore islands such as the Caribbean islands in the Atlantic, Hawaii
and French Polynesia
in the Pacific and the Seychelles
and Maldives
in the Indian Ocean. Black jack are rare in shallow waters, preferring deep reef
s, ledges and seamount
s in clear waters. The species is easily distinguished by its black to grey fins and jet black scute
s, with the head having a steep profile near the snout. The largest recorded length is 1 m and weight of 17.9 kg
. The black jack lives either individually or in small schools, and is known to school with other species. It is a predatory fish, taking a variety of fish, crustacean
s and molluscs as prey. Sexual maturity
is reached at 34.6 cm in females and 38.2 cm in males, with spawning
taking place between February and September in the Caribbean. The early life history of the species is very poorly understood. Black jack are of high importance to many island fisheries, but are rarely encountered in most continental fisheries. The species has a reputation as a gamefish, and is variably considered a terrible or excellent food fish, although several cases of ciguatera
poisoning have been attributed to the species. The species was initially named Caranx ascensionis by Georges Cuvier
, however several issues with the use of this name have seen Felipe Poey
's name Caranx lugubris become the valid scientific name.
, 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 taxonomic history
of the black jack is quite complex, with the species first referred to in error as Scomber adscensionis (Osbeck, 1771), which was also used to describe what is now known as Pseudocaranx dentex. Georges Cuvier
resurrected this name when he described the species as Caranx ascensionis in 1833. This was the first naming pertaining to the fish, and would normally have priority over any names assigned later. However the species as it is currently known, was first scientifically described in 1860 by the Cuba
n zoologist Felipe Poey
in his two volume
work Historia Natural de la Isla de Cuba, or "Natural History of the Island
of Cuba
". He assigned the species to the jack genera Caranx, and gave the Latin specific epithet of lugubris, meaning "mournful", or "pertaining to mourning". Although the description was based on a fish from Cuba, no holotype
is known for the species. Poey initially described his species as different from Cuvier's C. ascensionis, however he later placed both C. lugubris and another species he had named, C. frontalis, in synonymy with C. ascensionis. In later work, Poey again listed these three names as synonyms, but treated C. lugubris as valid, noting that Cuvier's name had also been used for Pseudocaranx dentex. Most later taxonomic revisions supported Poey's judgement, with the name C. ascensionis often considered a junior secondary homonym. William Smith-Vaniz and John Randall put forth a proposal to the ICZN
in 1994 to formally instate C. lugubris as the species name, which was accepted in 1996.
The species common name
s all refer to the black hue displayed by the fish, with the name 'black jack' most commonly used. Other names include 'black trevally', 'black kingfish', 'coal fish' and 'black ulua' in Hawaii.
, although is more common at lengths under 70 cm. At least one source asserts a fish of 2.21 m has been reported, which if true would make the black jack the second largest species of carangid behind the yellowtail amberjack (2.5 m). The black jack has a similar overall body shape to the other members of Caranx, having an oblong
, compressed form, with the dorsal profile more convex than the ventral profile. This convexity is most pronounced at the head, which slopes steeply downwards, giving the head profile a very angular appearance. The profile between the snout and the nape
is concave, with this indent centered near the nostrils. The mouth is fairly large compared to other members of its genus
and the maxilla
extends to under the centre of the fish's eye
. The upper jaw contains a series of strong outer canine
s with an inner band of smaller teeth, while the lower jaw contains a single row of widely spaced conical teeth. The dorsal fin
of the black jack is in two sections; the first has 8 spines and the second 1 spine and 20 to 22 soft rays. The anal fin has 2 anteriorly detached spines and 16 to 19 soft rays. The lobes of both the dorsal and anal fins are elongated. The pelvic fins contain 1 spine and 21 soft rays, while the pectoral fins are falcate and longer than 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 around 50 scales
while the straight section 26 to 32 strong scute
s. The caudal peduncle also has paired bilateral keels. The chest is completely covered in scale
s, which like the rest of the body are small and cycloid in nature. The species has 23 to 30 gill raker
s in total and there are 24 vertebrae present.
The body of the black jack is a uniform olive to brown, grey and even black
colour along the back that lightens to a grey-blue near the underside of the fish. The black jack's fins are grey to black, and the scutes are black. The upper limit of the operculum often has a small dark spot present, usually smaller than the pupil.
equator
ial oceans, thereby inhabiting the tropical and subtropical regions of the Atlantic, Pacific and Indian Ocean
s. In the Indian Ocean, they are found from Natal, South Africa
in the west to northern Australia
in the east. They are patchily distributed along the east Africa
n and Asia
n coastline in the Indian Ocean, being absent from both the Persian Gulf
and Red Sea
, as well as several countries bordering the ocean. The species is widely known from many Indian Ocean islands including the Seychelles
, Réunion
, Mauritius
and Cargados Carajos
In the Pacific Ocean, the black jack is known from parts of the Indonesian-Australian archipelago north to Japan
, and through many of the Pacific Islands such as Hawaii
, New Caledonia
and Tonga
. The species range in the eastern Pacific has been ranges from Mexico
and the Revillagigedo Islands
in the north to Costa Rica
in the south. In the western Atlantic Ocean
, black jack have been found from North Carolina
in the U.S. south to Rio de Janero, with the species most common in the Caribbean
and the northern Gulf of Mexico
. In the eastern Atlantic, the species has been reported from the Azores
, Madeira
St. Paul's Rocks, Ascension Island
, and the Gulf of Guinea
.
The black jack is a benthopelagic species rarely found in shallow inshore waters, preferring deep, clear offshore waters of depths from 12 to 354 m. The species is most common in insular ocean
ic habitats and around offshore islands, rarely found close to the continents. The black jack inhabits deep reef
s and reef drop offs, also being common around oceanic seamount
s. It has been recorded from lagoon
s in the Solomon Islands.
of up to 30 individuals. Like several other jacks, black jack are able to coordinate these aggregations over coral reef
s based on the release of dimethylsulfoniopropionate
(DMSP) from the reef. DMSP is a naturally occurring chemical produced by marine algae and to a lesser extent coral
s and their symbiotic zooxanthellae. In the Atlantic the species has also been video-recorded schooling with the almaco jack
, Seriola rivoliana, and the greater amberjack
, Seriola dumerili. The diet of the species has been reported on two occasions; once from Easter Island
in the south Pacific, where the diet consisted mainly of fish and crustacean
s including stomatopods and isopods; and from Brazil
, where a variety of fish, crustaceans and molluscs were taken. There is also some suggestion that in Brazil the species may be competing for food with the red snapper
, Lutjanus campechanus, with both having almost identical diets. The black jack is also known to follow spinner dolphins to feed off their excrements. The life history of the species has been determined in part from the waters of Jamaica
. Here the Male:Female sex ratio
s have been reported as 1:0.55, indicating males are nearly twice as common than females. The black jack reaches sexual maturity
at 34.6 cm in females and 38.2 cm in males. The timing of spawning
is poorly known, with occurrences recorded in February, April, May and July to September. The reproductive behaviour and early life history of the species is entirely unknown. Analysis of black jack catches suggest the average length of the fish is 50 cm for males and 48 cm for females.
s and traps as well as by hook and line. Black jack are usually marketed as fresh, whole fish, but they are also sold salted
or dried. The species rarity in most areas means it is not a major target for anglers, however some offshore locations such as the Bahamas the black jack is an important gamefish. The species appeal as a food fish varies between location, with some regions considering it the best table fish available. Despite this, numerous ciguatera
poisoning cases have been attributed to the black jack, with laboratory tests confirming the presence of the toxin
in the species flesh.
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
in the jack family
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
Carangidae
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
. The species has a circumtropical distribution, found in oceanic, offshore waters of the tropical zones of the Pacific, Atlantic and Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
s. The species is particularly prevalent around offshore islands such as the Caribbean islands in the Atlantic, Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
and French Polynesia
French Polynesia
French Polynesia is an overseas country of the French Republic . It is made up of several groups of Polynesian islands, the most famous island being Tahiti in the Society Islands group, which is also the most populous island and the seat of the capital of the territory...
in the Pacific and the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
and Maldives
Maldives
The Maldives , , officially Republic of Maldives , also referred to as the Maldive Islands, is an island nation in the Indian Ocean formed by a double chain of twenty-six atolls oriented north-south off India's Lakshadweep islands, between Minicoy Island and...
in the Indian Ocean. Black jack are rare in shallow waters, preferring deep reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s, ledges and seamount
Seamount
A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...
s in clear waters. The species is easily distinguished by its black to grey fins and jet black scute
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s, with the head having a steep profile near the snout. The largest recorded length is 1 m and weight of 17.9 kg
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
. The black jack lives either individually or in small schools, and is known to school with other species. It is a predatory fish, taking a variety of fish, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and molluscs as prey. Sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
is reached at 34.6 cm in females and 38.2 cm in males, with spawning
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
taking place between February and September in the Caribbean. The early life history of the species is very poorly understood. Black jack are of high importance to many island fisheries, but are rarely encountered in most continental fisheries. The species has a reputation as a gamefish, and is variably considered a terrible or excellent food fish, although several cases of ciguatera
Ciguatera
Ciguatera is a foodborne illness caused by eating certain reef fishes whose flesh is contaminated with toxins originally produced by dinoflagellates such as Gambierdiscus toxicus which lives in tropical and subtropical waters. These dinoflagellates adhere to coral, algae and seaweed, where they are...
poisoning have been attributed to the species. The species was initially named Caranx ascensionis by Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
, however several issues with the use of this name have seen Felipe Poey
Felipe Poey
-Biography:Poey was born in Havana, the son of French and Spanish parents. He spent several years of his life in Pau then studied law in Madrid. He became a lawyer in Spain but was forced to leave due to his liberal ideas, returning to Cuba in 1823. He began to concentrate on the study of the...
's name Caranx lugubris become the valid scientific name.
Taxonomy and naming
The black jack is classified within the genus CaranxCaranx
Caranx is a genus of tropical to subtropical marine fish 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...
, 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
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
, a group of percoid
Percoidei
Percoidei is one of eighteen suborders of bony fish in the order Perciformes. Many commercially harvested fish species are contained in this suborder, including the snappers, jacks, whitings, groupers, bass, perches and porgies.-Divisions:...
fishes in the order Perciformes
Perciformes
The Perciformes, also called the Percomorphi or Acanthopteri, is one of the largest orders of vertebrates, containing about 40% of all bony fish. Perciformes means perch-like. They belong to the class of ray-finned fish and comprise over 7,000 species found in almost all aquatic environments...
.
The taxonomic history
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
of the black jack is quite complex, with the species first referred to in error as Scomber adscensionis (Osbeck, 1771), which was also used to describe what is now known as Pseudocaranx dentex. Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
resurrected this name when he described the species as Caranx ascensionis in 1833. This was the first naming pertaining to the fish, and would normally have priority over any names assigned later. However the species as it is currently known, was first scientifically described in 1860 by the Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
n zoologist Felipe Poey
Felipe Poey
-Biography:Poey was born in Havana, the son of French and Spanish parents. He spent several years of his life in Pau then studied law in Madrid. He became a lawyer in Spain but was forced to leave due to his liberal ideas, returning to Cuba in 1823. He began to concentrate on the study of the...
in his two volume
Volume
Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
work Historia Natural de la Isla de Cuba, or "Natural History of the Island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
of Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
". He assigned the species to the jack genera Caranx, and gave the Latin specific epithet of lugubris, meaning "mournful", or "pertaining to mourning". Although the description was based on a fish from Cuba, no holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
is known for the species. Poey initially described his species as different from Cuvier's C. ascensionis, however he later placed both C. lugubris and another species he had named, C. frontalis, in synonymy with C. ascensionis. In later work, Poey again listed these three names as synonyms, but treated C. lugubris as valid, noting that Cuvier's name had also been used for Pseudocaranx dentex. Most later taxonomic revisions supported Poey's judgement, with the name C. ascensionis often considered a junior secondary homonym. William Smith-Vaniz and John Randall put forth a proposal to the ICZN
International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 28 members from 20 countries, mainly practicing zoological taxonomists...
in 1994 to formally instate C. lugubris as the species name, which was accepted in 1996.
The species common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s all refer to the black hue displayed by the fish, with the name 'black jack' most commonly used. Other names include 'black trevally', 'black kingfish', 'coal fish' and 'black ulua' in Hawaii.
Description
The black jack is a large fish, and is confidently known to grow to a length of 1 m and a weight of 17.9 kgKilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
, although is more common at lengths under 70 cm. At least one source asserts a fish of 2.21 m has been reported, which if true would make the black jack the second largest species of carangid behind the yellowtail amberjack (2.5 m). The black jack has a similar overall body shape to the other members of Caranx, having an oblong
Rectangle
In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle...
, compressed form, with the dorsal profile more convex than the ventral profile. This convexity is most pronounced at the head, which slopes steeply downwards, giving the head profile a very angular appearance. The profile between the snout and the nape
Nape
The nape is the back of the neck. In technical anatomical/medical terminology, the nape is referred to by the word nucha, which also gives the adjective corresponding to "nape" in English, "nuchal"....
is concave, with this indent centered near the nostrils. The mouth is fairly large compared to other members of its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
and the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
extends to under the centre of the fish's eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
. The upper jaw contains a series of strong outer canine
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
s with an inner band of smaller teeth, while the lower jaw contains a single row of widely spaced conical teeth. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
of the black jack is in two sections; the first has 8 spines and the second 1 spine and 20 to 22 soft rays. The anal fin has 2 anteriorly detached spines and 16 to 19 soft rays. The lobes of both the dorsal and anal fins are elongated. The pelvic fins contain 1 spine and 21 soft rays, while the pectoral fins are falcate and longer than the head. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
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 around 50 scales
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
while the straight section 26 to 32 strong scute
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s. The caudal peduncle also has paired bilateral keels. The chest is completely covered in scale
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
s, which like the rest of the body are small and cycloid in nature. The species has 23 to 30 gill raker
Gill raker
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch and are involved with filter feeding tiny prey. They are not to be confused with the gill filaments that compose the bony part of the gill. Rakers are usually present in two rows, projecting from both the...
s in total and there are 24 vertebrae present.
The body of the black jack is a uniform olive to brown, grey and even black
Black
Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light...
colour along the back that lightens to a grey-blue near the underside of the fish. The black jack's fins are grey to black, and the scutes are black. The upper limit of the operculum often has a small dark spot present, usually smaller than the pupil.
Distribution and habitat
The black jack has a circumtropical distribution, meaning their range extends around the Earth'sEarth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
ial oceans, thereby inhabiting the tropical and subtropical regions of the Atlantic, Pacific and Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
s. In the Indian Ocean, they are found from Natal, South Africa
Natal, South Africa
Natal is a region in South Africa. It stretches between the Indian Ocean in the south and east, the Drakensberg in the west, and the Lebombo Mountains in the north. The main cities are Pietermaritzburg and Durban...
in the west to northern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
in the east. They are patchily distributed along the east Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n coastline in the Indian Ocean, being absent from both the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
and Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
, as well as several countries bordering the ocean. The species is widely known from many Indian Ocean islands including the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
, Réunion
Réunion
Réunion is a French island with a population of about 800,000 located in the Indian Ocean, east of Madagascar, about south west of Mauritius, the nearest island.Administratively, Réunion is one of the overseas departments of France...
, Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
and Cargados Carajos
Cargados Carajos
Cargados Carajos Shoals are a group of about 16 small islands and islets on an extended reef in the Indian Ocean northeast of Mauritius. The islands have a total land area of 1.3 km². The reef measures more than 50 km from north to south, and is 5 km wide, cut by three passes. The...
In the Pacific Ocean, the black jack is known from parts of the Indonesian-Australian archipelago north to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, and through many of the Pacific Islands such as Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
and Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
. The species range in the eastern Pacific has been ranges from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and the Revillagigedo Islands
Revillagigedo Islands
The Revillagigedo Islands or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem...
in the north to Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
in the south. In the western Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, black jack have been found from North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
in the U.S. south to Rio de Janero, with the species most common in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and the northern Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
. In the eastern Atlantic, the species has been reported from the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...
St. Paul's Rocks, Ascension Island
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
, and the Gulf of Guinea
Gulf of Guinea
The Gulf of Guinea is the northeasternmost part of the tropical Atlantic Ocean between Cape Lopez in Gabon, north and west to Cape Palmas in Liberia. The intersection of the Equator and Prime Meridian is in the gulf....
.
The black jack is a benthopelagic species rarely found in shallow inshore waters, preferring deep, clear offshore waters of depths from 12 to 354 m. The species is most common in insular ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
ic habitats and around offshore islands, rarely found close to the continents. The black jack inhabits deep reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s and reef drop offs, also being common around oceanic seamount
Seamount
A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...
s. It has been recorded from lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
s in the Solomon Islands.
Biology and ecology
The black jack lives both in solitude and in schoolsShoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
of up to 30 individuals. Like several other jacks, black jack are able to coordinate these aggregations over coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s based on the release of dimethylsulfoniopropionate
Dimethylsulfoniopropionate
Dimethylsulfoniopropionate , is an organosulfur compound with the formula 2S+CH2CH2COO−. This zwitterionic metabolite found in marine phytoplankton, seaweeds, and some species of terrestrial and aquatic vascular plants...
(DMSP) from the reef. DMSP is a naturally occurring chemical produced by marine algae and to a lesser extent coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
s and their symbiotic zooxanthellae. In the Atlantic the species has also been video-recorded schooling with the almaco jack
Almaco jack
Almaco jack is a game fish of the family Carangidae; they are in the same family as yellowtail and amberjack. They feed, both day and night, on other, smaller, fish, such as baitfish and small squid. The flesh is thick and dense like tuna and can easily pass for white albacore if prepared as sushi...
, Seriola rivoliana, and the greater amberjack
Greater amberjack
The Greater amberjack is a jack of the genus Seriola. It is found in the Mediterranean Sea, the Atlantic Ocean, the Pacific Ocean and the Indian coasts, living usually between 20 and 70 m of depth...
, Seriola dumerili. The diet of the species has been reported on two occasions; once from Easter Island
Easter Island
Easter Island is a Polynesian island in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian triangle. A special territory of Chile that was annexed in 1888, Easter Island is famous for its 887 extant monumental statues, called moai, created by the early Rapanui people...
in the south Pacific, where the diet consisted mainly of fish and crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s including stomatopods and isopods; and from Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, where a variety of fish, crustaceans and molluscs were taken. There is also some suggestion that in Brazil the species may be competing for food with the red snapper
Red snapper (fish)
The red snapper, Lutjanus campechanus, is a fish found in the Gulf of Mexico and the southeastern Atlantic coast of the United States and, much less commonly, northward as far as Massachusetts. In Latin American Spanish it is known as huachinango or pargo...
, Lutjanus campechanus, with both having almost identical diets. The black jack is also known to follow spinner dolphins to feed off their excrements. The life history of the species has been determined in part from the waters of Jamaica
Jamaica
Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...
. Here the Male:Female sex ratio
Sex ratio
Sex ratio is the ratio of males to females in a population. The primary sex ratio is the ratio at the time of conception, secondary sex ratio is the ratio at time of birth, and tertiary sex ratio is the ratio of mature organisms....
s have been reported as 1:0.55, indicating males are nearly twice as common than females. The black jack reaches sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at 34.6 cm in females and 38.2 cm in males. The timing of spawning
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
is poorly known, with occurrences recorded in February, April, May and July to September. The reproductive behaviour and early life history of the species is entirely unknown. Analysis of black jack catches suggest the average length of the fish is 50 cm for males and 48 cm for females.
Relationship to humans
The black jack is of moderate to high important to commercial fisheries throughout its range, often being the most abundant large carangid in offshore island catches. The species is taken by both various netFishing net
A fishing net or fishnet is a net that is used for fishing. Fishing nets are meshes usually formed by knotting a relatively thin thread. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and...
s and traps as well as by hook and line. Black jack are usually marketed as fresh, whole fish, but they are also sold salted
Salting (food)
Salting is the preservation of food with dry edible salt. It is related to pickling . It is one of the oldest methods of preserving food, and two historically significant salt-cured foods are dried and salted cod and salt-cured meat.Salting is used because most bacteria, fungi and other potentially...
or dried. The species rarity in most areas means it is not a major target for anglers, however some offshore locations such as the Bahamas the black jack is an important gamefish. The species appeal as a food fish varies between location, with some regions considering it the best table fish available. Despite this, numerous ciguatera
Ciguatera
Ciguatera is a foodborne illness caused by eating certain reef fishes whose flesh is contaminated with toxins originally produced by dinoflagellates such as Gambierdiscus toxicus which lives in tropical and subtropical waters. These dinoflagellates adhere to coral, algae and seaweed, where they are...
poisoning cases have been attributed to the black jack, with laboratory tests confirming the presence of the toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
in the species flesh.