Bar jack
Encyclopedia
The bar jack, Carangoides ruber (also known as the carbonero, red jack, blue-striped cavalla and passing jack) is a common species
of inshore marine
fish
classified in the jack family, Carangidae
. The bar jack is distributed through the western Atlantic Ocean
from New Jersey
and Bermuda
in the north to Venezuela
and possibly Brazil
in the south, with the largest population in the Gulf of Mexico
and West Indies. The bar jack is most simply distinguished from similar jacks by its dark horizontal bar which runs along the back and down the caudal fin, often accompanied by an electric blue stripe immediately below it. Other more detailed differences include dentition and soft ray counts. The bar jack is a moderately large species, growing to a recorded maximum of 65 cm and a weight of 6.8 kg. The species inhabits clear shallow waters, often over coral reef
s where it lives either solitarily or in large schools
, taking various fishes, crustacean
s and cephalopod
s as prey. Studies in Cuba
indicate spawning
occurs between March and August, with sexual maturity
reached at 26 cm. It is a relatively popular sport fish
and can be caught on light tackle
with a variety of lures and baits. It is considered to be a good food fish, however many recorded ciguatera
cases are attributed to the species, with most cases reported on the island
of St. Thomas
traced to this single species.
, a group of fishes commonly known as jacks and trevallies, which is part of the larger jack and horse mackerel family Carangidae
. The Carangidae are perciform fishes in the suborder Percoidei
. The fish is still often classified in the genus Caranx
by most authors, including in the most recent review of the species by William Smith-Vaniz, but the major taxonomic authorities Fishbase
and ITIS
both list it as under Carangoides, which this article follows.
The bar jack was first scientifically described under the name Somber ruber by Marcus Bloch
, in 1793 based on a specimen taken from the east coast of America, which was designated to be the holotype
. Carangoides is derived from the French word, carangue, or a fish from the Caribbean
, while ruber (sometimes incorrectly spelled rubber) is Latin
for red. Bloch attributed the species to the mackerels of the genus Scomber
, a common practice during this period as the genus Caranx and subsequent family Carangidae were not created until 1801 by Bernard Germain de Lacépède. The species has been variably placed in either Carangoides or Caranx since 1801, with the status of the species still somewhat ambiguous. A recent study of the molecular systematics of the Carangidae using mitochondrial cytochrome b
sequences strongly supported placement in the genus Caranx, with C. ruber being most closely related to Caranx bartholomaei
, itself still often classified under Carangoides. Both C. ruber and C. bartholomaei were strongly related to other well known members of Caranx, and only distantly related to any other species of Carangoides.
Aside from the most commonly used name of "bar jack", other common name
s for this fish include blue-striped cavalla, red jack, neverbite, passing jack, and pointnose, as well as many non-English names.
The bar jack is a moderately large species, growing to a recorded maximum length of 69 cm, and a weight of 6.8 kg, but is commonly encountered at lengths of less than 40 cm. The bar jack displays the typical body shape of most of the jacks, having an elongate, moderately deep and compressed form, with dorsal and ventral profiles of approximately equal convexity. The dorsal fin
is divided into two sections, the first consisting of 8 spines while the second has 1 spine followed by 26 to 30 soft rays. The anal fin is composed of 2 anteriorly detached spines followed by 1 spine and 23 to 26 soft rays, with both the anal and soft dorsal fin lobes being slightly elongated. The pectoral fins are falcate and longer than the head, consisting of 19 to 21 soft rays. The lateral line
is moderately arched anteriorly, and possesses 17 to 104 scales
including 23 to 29 scute
s posteriorly; also having bilateral paired caudal keels present. The chest is completely scaled, which easily distinguishes it from the similar crevalle jack
, Caranx hippos. The snout is moderately pointed, with both the jaw
s containing narrow bands of villiform teeth, with the bands becoming wider anteriorly. The upper jaw also contains an outer row of enlarged recurved teeth. There are 10 to 14 upper limb gill raker
s, and 31 to 38 on the lower limb and 24 vertebrae.
The bar jack has a gray to grayish blue upper body with a silvery tint, which fades ventrally to a white belly. As indicated by their common name, adult bar jack have a horizontal stripe running along their back and through the lower lobe of the caudal fin. This bar is a golden brownish to blackish color, often with an electric blue
bar running parallel immediately underneath it. All other fins are pale dusky to hyaline
. Juveniles have up to 6 dark bands on their body and a darker lower caudal lobe than the upper lobe, foreshadowing the bar that develops at a later stage. At these early stages, they are difficult to distinguish from Carangoides bartholomaei, with the best identifier being gill raker counts. The entire body has been observed to change colour to a blackish colour when the fish is feeding near the bottom.
, and is a common species throughout most of its range. The northernmost limit of its range is New Jersey
in the northern United States
, with its range extending south along the continental coast to Venezuela
. It inhabits a number of offshore islands and archipelagos including Bermuda
, as well as the West Indies. The bar jack is most abundant in the Gulf of Mexico
, the West Indies and Caribbean, but in the Gulf of Mexico is limited to offshore waters. There have been reliable reports of the species from Rio de Janeiro
in Brazil
and far offshore at Saint Helena
in the south central Atlantic, which would extend the species southern limit significantly if correct.
The bar jack generally live in clear shallow water environments, predominantly around coral reefs to depths of around 60 ft. Tagging
studies demonstrate the species is highly mobile, not lingering over one particular reef patch for very long, often moving between reefs over large expanses of sand. Bar jack often venture into lagoon
s from seaward reefs, preferring to move over the sandy substrate while in these shallow waters, often forming shoals alongside barracuda
, stingray
s and shark
s. Unlike most fish live on both the lagoon and reef, there is no particular age partitioning, with both juveniles and adults entering the lagoon to forage. Records of bar jack taken from Saint Helena came from seamount
s in waters deeper than 100 m, indicating they live in more offshore pelagic waters also. Juveniles are often found under floating sargassum
mats, using the algae for protection. They also inhabit areas around docks and pilings. Juveniles can be caught using a sabiki
rig.
of the bar jack are relatively well documented, with most studies centered around the waters of Cuba
during the 1980s, with nearly all of this research published in the Russian
publication Voprosy Ikhtiologii, reprinted in English as the Journal of Ichthyology. The movements of the species between patches has also been studied and is presented above. The bar jack is commonly taken as prey by a number of other large carangids as well as dolphinfish, mackerel
s, marlin
s and various seabird
s.
The bar jack is a benthopelagic predator, taking its prey both in midwater and along the seafloor. The diet consists mostly of fish, up to 90% of the fishes intake in some studies, with plankton
ic crustacean
s and small cephalopod
s taken in minor volumes. There is significant change in diet with age in fish studied off Cuba, which may reduce intraspecific competition
in the species. Young fish prefer planktonic organisms, predominantly decapod
and fish larvae; fish reaching sexual maturity prey on shrimp
and small fish, while mature fish feed almost exclusively on small fish. The fish species preferred by bar jack appear to be mostly small sand dwellers such as blennies and gobies
or small reef dwellers including wrasse
s, butterflyfish
and filefish
, with the diet of the latter leading to the accumulation of coral derived ciguatera
toxin in the jack's flesh. Other lesser taken prey items include gastropods, nematode
s and benthic algae
as well as a range of crustaceans.
Feeding intensity varies throughout the year, and is strongly correlated to changes in the precipitation
and wind
during cyclical shifts in the climate. Young fish tend to feed intensively throughout the year, but show a peak in the spring and autumn months, while adults intensify their feeding during the dry and rainy seasons, with feeding declining during intermediate periods (winter and early summer). Daily intakes during the period of intensive feeding reach 3–7% of the fishes body weight
, and during the periods of decline to 0.5–2%, with the annual intake being 1000–1500% of the body weight. In a 1993 paper, Troy Baird reported a foraging
association between bar jacks and puddingwife wrasse
, Halichoeres radiatus, in which a jack followed a single wrasse while it foraged for food. These associations were initiated by both jacks and wrasse, with apparently little pilfering of uncovered items, suggesting a beneficial relationship to both parties. While foraging with the wrasse, the jack increases its prey detection levels, which is useful for a species which is more adept at pelagic hunting, allowing it to be more efficient at this less common mode of food gathering.
, which occurs through the period from March to August in Cuba, with peaks during March–April and June–July.
Fish congregate in schools of hundreds to spawn, with pairs of fish breaking away to spawn. Studies have found between 67 000 and 231 000 eggs are released by each female, with fertilisation occurring externally. The eggs are pelagic and around 0.75 mm to 0.85 mm in diameter
, hatching when the larvae are around 2 mm in length, and flexion
occurs at 4–5 mm. The larval stage of the bar jack has been extensively described by Richards (2006). Larvae appear between April and October in the Gulf Stream
current, and grow the fastest during their first three years of life.
During this early stage of life they are very similar to Carangoides bartholomaei, and often form associations with floating pelagic Sargassum mats which provide the young fish with protection. Young fish often inhabit the shallow reef waters, but move offshore once they reach sexual maturity
. Due to a lack of discernible otolith
rings, no studies on the growth of the bar jack have been published. Males and females reach sexual maturity at different lengths; males at 25 cm and females at 31 cm.
The bar jack is of minor to intermediate importance to fisheries through its range; both commercially and to recreational fishermen
. Archaeological evidence from San Salvador Island
in the Bahamas demonstrates this species has long been targeted by humans for food, with the native Indians
of the region often taking the bar jack for consumption, although it was of lesser importance than reef fishes such as parrotfishes and grouper
s. Modern fisheries take considerable quantities of the fish, but it rarely makes up the bulk of the catch. Catch statistics are not available for most countries. The United States reports only a small catch of between 0 and 15 tonne
s per year, but with the abundance of the species in the Caribbean
, larger catches are made here. The bar jack is somewhat shy of baited hooks
and is therefore taken predominantly by trawls and seines. It is marketed fresh in the Antilles
and Bahamas, with its edibility
rated fair to very good.
The bar jack is a popular light tackle game fish
, taken predominantly on small lures
and flies
, with the species considered to be an excellent fighter on light tackle. The species is often sighted working small baitfish to the surface, where they can be targeted with surface poppers or various fly patterns. As mentioned previously, they rarely take baited hooks. The species is often used as bait for larger game fish such as marlin and sailfish
.
The bar jack has a significant risk of carrying the ciguatera
toxin in its flesh, and numerous reports of people contracting the poisoning after consuming the fish. A comprehensive study of the toxin in the West Indies listed the bar jack as a species of intermediate risk of carrying the toxin,
although most cases in St. Thomas
of the Virgin Islands
can be traced back to the bar jack.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of inshore marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
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...
classified in the jack 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...
. The bar jack is distributed through 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...
from New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
and Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
in the north to Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
and possibly 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...
in the south, with the largest population in the 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...
and West Indies. The bar jack is most simply distinguished from similar jacks by its dark horizontal bar which runs along the back and down the caudal fin, often accompanied by an electric blue stripe immediately below it. Other more detailed differences include dentition and soft ray counts. The bar jack is a moderately large species, growing to a recorded maximum of 65 cm and a weight of 6.8 kg. The species inhabits clear shallow waters, often 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 where it lives either solitarily or in large schools
Shoaling 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...
, taking various fishes, 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 cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s as prey. Studies in 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...
indicate 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...
occurs between March and August, with 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...
reached at 26 cm. It is a relatively popular sport fish
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
and can be caught on light tackle
Fishing tackle
Fishing tackle, is a general term that refers to the equipment used by fishermen when fishing. Almost any equipment or gear used for fishing can be called fishing tackle. Some examples are hooks, lines, sinkers, floats, rods, reels, baits, lures, spears, nets, gaffs, traps, waders and tackle...
with a variety of lures and baits. It is considered to be a good food fish, however many recorded 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...
cases are attributed to the species, with most cases reported on 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 St. Thomas
Saint Thomas, U.S. Virgin Islands
Saint Thomas is an island in the Caribbean Sea and with the islands of Saint John, Saint Croix, and Water Island a county and constituent district of the United States Virgin Islands , an unincorporated territory of the United States. Located on the island is the territorial capital and port of...
traced to this single species.
Taxonomy and naming
The bar jack is classified within the genus CarangoidesCarangoides
Carangoides is a genus of tropical to subtropical marine fishes in the jack family, Carangidae. They are small to large sized, deep bodied fish characterised by a certain gill raker and jaw morphology, often appearing very similar to jacks in the genus Caranx...
, a group of fishes commonly known as jacks and trevallies, which 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...
. The Carangidae are perciform fishes in the suborder Percoidei
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:...
. The fish is still often classified in the genus Caranx
Caranx
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...
by most authors, including in the most recent review of the species by William Smith-Vaniz, but the major taxonomic authorities Fishbase
FishBase
FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...
and ITIS
Itis
Itis may refer to* Integrated Taxonomic Information System, a partnership designed to provide consistent and reliable information on the taxonomy of biological species...
both list it as under Carangoides, which this article follows.
The bar jack was first scientifically described under the name Somber ruber by Marcus Bloch
Marcus Elieser Bloch
Marcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...
, in 1793 based on a specimen taken from the east coast of America, which was designated to be the 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...
. Carangoides is derived from the French word, carangue, or a fish from 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...
, while ruber (sometimes incorrectly spelled rubber) is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for red. Bloch attributed the species to the mackerels of the genus Scomber
Scomber
Scomber is a genus of ocean-dwelling mackerels in the family Scombridae.-Species:FishBase lists four species:* Blue mackerel, Scomber australasicus Cuvier, 1832.* Atlantic Chub Mackerel, Scomber colias Gmelin, 1789....
, a common practice during this period as the genus Caranx and subsequent family Carangidae were not created until 1801 by Bernard Germain de Lacépède. The species has been variably placed in either Carangoides or Caranx since 1801, with the status of the species still somewhat ambiguous. A recent study of the molecular systematics of the Carangidae using mitochondrial cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
sequences strongly supported placement in the genus Caranx, with C. ruber being most closely related to Caranx bartholomaei
Yellow jack
The yellow jack, Carangoides bartholomaei , is a species of offshore marine fish in the jack family, Carangidae. It is one of only two representatives of its genus present in the Atlantic Ocean, inhabiting waters off the east coast of the Americas from Massachusetts in the north to Brazil in the...
, itself still often classified under Carangoides. Both C. ruber and C. bartholomaei were strongly related to other well known members of Caranx, and only distantly related to any other species of Carangoides.
Aside from the most commonly used name of "bar jack", other 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 for this fish include blue-striped cavalla, red jack, neverbite, passing jack, and pointnose, as well as many non-English names.
Description
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...
is divided into two sections, the first consisting of 8 spines while the second has 1 spine followed by 26 to 30 soft rays. The anal fin is composed of 2 anteriorly detached spines followed by 1 spine and 23 to 26 soft rays, with both the anal and soft dorsal fin lobes being slightly elongated. The pectoral fins are falcate and longer than the head, consisting of 19 to 21 soft rays. 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...
is moderately arched anteriorly, and possesses 17 to 104 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...
including 23 to 29 scute
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 posteriorly; also having bilateral paired caudal keels present. The chest is completely scaled, which easily distinguishes it from the similar crevalle jack
Crevalle jack
The crevalle jack, Caranx hippos is a common species of large marine fish classified within the jack family, Carangidae...
, Caranx hippos. The snout is moderately pointed, with both the jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
s containing narrow bands of villiform teeth, with the bands becoming wider anteriorly. The upper jaw also contains an outer row of enlarged recurved teeth. There are 10 to 14 upper limb 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, and 31 to 38 on the lower limb and 24 vertebrae.
The bar jack has a gray to grayish blue upper body with a silvery tint, which fades ventrally to a white belly. As indicated by their common name, adult bar jack have a horizontal stripe running along their back and through the lower lobe of the caudal fin. This bar is a golden brownish to blackish color, often with an electric blue
Electric blue
Electric blue is a very bright color reminiscent of a spark, named after the color of an argon sign. It is very similar to cyan.Additionally, the term may refer to:-Biology:...
bar running parallel immediately underneath it. All other fins are pale dusky to hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
. Juveniles have up to 6 dark bands on their body and a darker lower caudal lobe than the upper lobe, foreshadowing the bar that develops at a later stage. At these early stages, they are difficult to distinguish from Carangoides bartholomaei, with the best identifier being gill raker counts. The entire body has been observed to change colour to a blackish colour when the fish is feeding near the bottom.
Distribution and habitat
The bar jack is widely distributed through the tropical and subtropical waters of the western Atlantic OceanAtlantic 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...
, and is a common species throughout most of its range. The northernmost limit of its range is New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
in the northern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, with its range extending south along the continental coast to Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
. It inhabits a number of offshore islands and archipelagos including Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
, as well as the West Indies. The bar jack is most abundant in the 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...
, the West Indies and Caribbean, but in the Gulf of Mexico is limited to offshore waters. There have been reliable reports of the species from Rio de Janeiro
Rio de Janeiro
Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
in 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...
and far offshore at Saint Helena
Saint Helena
Saint Helena , named after St Helena of Constantinople, is an island of volcanic origin in the South Atlantic Ocean. It is part of the British overseas territory of Saint Helena, Ascension and Tristan da Cunha which also includes Ascension Island and the islands of Tristan da Cunha...
in the south central Atlantic, which would extend the species southern limit significantly if correct.
The bar jack generally live in clear shallow water environments, predominantly around coral reefs to depths of around 60 ft. Tagging
Electronic tagging
Electronic tagging is a form of non-surreptitious surveillance consisting of an electronic device attached to a person or vehicle, especially certain criminals, allowing their whereabouts to be monitored. In general, devices locate themselves using GPS and report their position back to a control...
studies demonstrate the species is highly mobile, not lingering over one particular reef patch for very long, often moving between reefs over large expanses of sand. Bar jack often venture into 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 from seaward reefs, preferring to move over the sandy substrate while in these shallow waters, often forming shoals alongside barracuda
Barracuda
The barracuda is a ray-finned fish known for its large size and fearsome appearance. Its body is long, fairly compressed, and covered with small, smooth scales. Some species could reach up to 1.8m in length and 30 cm in width...
, stingray
Stingray
The stingrays are a group of rays, which are cartilaginous fishes related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes, and consist of eight families: Hexatrygonidae , Plesiobatidae , Urolophidae , Urotrygonidae , Dasyatidae , Potamotrygonidae The...
s and shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s. Unlike most fish live on both the lagoon and reef, there is no particular age partitioning, with both juveniles and adults entering the lagoon to forage. Records of bar jack taken from Saint Helena came from 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 waters deeper than 100 m, indicating they live in more offshore pelagic waters also. Juveniles are often found under floating sargassum
Sargassum
Sargassum is a genus of brown macroalga in the order Fucales. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they generally inhabit shallow water and coral reefs. However, the genus may be best known for its planktonic species...
mats, using the algae for protection. They also inhabit areas around docks and pilings. Juveniles can be caught using a sabiki
Sabiki
A sabiki rig, sometimes called a piscatore rig, is a set of small lures typically used to catch plankton-eating fish. A sabiki is typically fished off boats, piers, jetties, or any structure over the water. Sabikis consist of any number of small hooks each on a dropper line which is a few inches...
rig.
Biology
The diet and reproductive biologyReproductive biology
Reproductive biology is a study mainly involving the reproductive system and sex organs. It is closely related to reproductive endocrinology and infertility. also is miotosis and miosis...
of the bar jack are relatively well documented, with most studies centered around the waters 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...
during the 1980s, with nearly all of this research published in the Russian
Russian language
Russian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...
publication Voprosy Ikhtiologii, reprinted in English as the Journal of Ichthyology. The movements of the species between patches has also been studied and is presented above. The bar jack is commonly taken as prey by a number of other large carangids as well as dolphinfish, mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
s, marlin
Marlin
Marlin, family Istiophoridae, are fish with an elongated body, a spear-like snout or bill, and a long rigid dorsal fin, which extends forward to form a crest. Its common name is thought to derive from its resemblance to a sailor's marlinspike...
s and various seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s.
Diet and feeding
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic 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 small cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s taken in minor volumes. There is significant change in diet with age in fish studied off Cuba, which may reduce intraspecific competition
Intraspecific competition
Intraspecific competition is a particular form of competition in which members of the same species vie for the same resource in an ecosystem...
in the species. Young fish prefer planktonic organisms, predominantly decapod
Decapoda
The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
and fish larvae; fish reaching sexual maturity prey on shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
and small fish, while mature fish feed almost exclusively on small fish. The fish species preferred by bar jack appear to be mostly small sand dwellers such as blennies and gobies
Goby
The gobies form the family Gobiidae, which is one of the largest families of fish, with more than 2,000 species in more than 200 genera. Most are relatively small, typically less than 10 cm in length...
or small reef dwellers including wrasse
Wrasse
The wrasses are a family, Labridae, of marine fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 82 genera, which are divided into nine subgroups or tribes....
s, butterflyfish
Butterflyfish
The butterflyfish are a group of conspicuous tropical marine fish of the family Chaetodontidae; the bannerfish and coralfish are also included in this group. Found mostly on the reefs of the Atlantic, Indian and Pacific Oceans, there are approximately 120 species in 10 genera...
and filefish
Filefish
Filefish are tropical to subtropical tetraodontiform marine fish of the diverse family Monacanthidae. Found in the Atlantic, Pacific and Indian Oceans, the filefish family contains approximately 107 species in 26 genera...
, with the diet of the latter leading to the accumulation of coral derived 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...
toxin in the jack's flesh. Other lesser taken prey items include gastropods, nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s and benthic algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
as well as a range of crustaceans.
Feeding intensity varies throughout the year, and is strongly correlated to changes in the precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
and wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
during cyclical shifts in the climate. Young fish tend to feed intensively throughout the year, but show a peak in the spring and autumn months, while adults intensify their feeding during the dry and rainy seasons, with feeding declining during intermediate periods (winter and early summer). Daily intakes during the period of intensive feeding reach 3–7% of the fishes body weight
Body weight
The term body weight is used in daily English speech as well as in the contexts of biological and medical sciences to describe the mass of an organism's body. Body weight is measured in kilograms throughout the world, although in some countries it is still measured in pounds or stones and pounds...
, and during the periods of decline to 0.5–2%, with the annual intake being 1000–1500% of the body weight. In a 1993 paper, Troy Baird reported a foraging
Foraging
- Definitions and significance of foraging behavior :Foraging is the act of searching for and exploiting food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce...
association between bar jacks and puddingwife wrasse
Puddingwife wrasse
The puddingwife wrasse is found in the southern reefs of the Gulf of Mexico. This fish is green with a pinkish top with many green lines along the face. The puddingwife is small and at most reaches three or four pounds. Due to its small size, it is not generally eaten...
, Halichoeres radiatus, in which a jack followed a single wrasse while it foraged for food. These associations were initiated by both jacks and wrasse, with apparently little pilfering of uncovered items, suggesting a beneficial relationship to both parties. While foraging with the wrasse, the jack increases its prey detection levels, which is useful for a species which is more adept at pelagic hunting, allowing it to be more efficient at this less common mode of food gathering.
Reproduction and growth
The bar jack spawns twice each year, with this timing related to seasonal changes as described previously. During the peak feeding periods, the fish accumulate body fat in preparation for spawningSpawn (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...
, which occurs through the period from March to August in Cuba, with peaks during March–April and June–July.
Fish congregate in schools of hundreds to spawn, with pairs of fish breaking away to spawn. Studies have found between 67 000 and 231 000 eggs are released by each female, with fertilisation occurring externally. The eggs are pelagic and around 0.75 mm to 0.85 mm in diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
, hatching when the larvae are around 2 mm in length, and flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
occurs at 4–5 mm. The larval stage of the bar jack has been extensively described by Richards (2006). Larvae appear between April and October in the Gulf Stream
Gulf Stream
The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean...
current, and grow the fastest during their first three years of life.
During this early stage of life they are very similar to Carangoides bartholomaei, and often form associations with floating pelagic Sargassum mats which provide the young fish with protection. Young fish often inhabit the shallow reef waters, but move offshore once they reach 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...
. Due to a lack of discernible otolith
Otolith
An otolith, , also called statoconium or otoconium is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates. The saccule and utricle, in turn, together make the otolith organs. They are sensitive to gravity and linear acceleration...
rings, no studies on the growth of the bar jack have been published. Males and females reach sexual maturity at different lengths; males at 25 cm and females at 31 cm.
Relationship to humans
Angling
Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...
. Archaeological evidence from San Salvador Island
San Salvador Island
San Salvador Island, also known as Watlings Island, is an island and district of the Bahamas. Until 1986, when the National Geographic Society suggested Samana Cay, it was widely believed that during his first expedition to the New World, San Salvador Island was the first land sighted and visited...
in the Bahamas demonstrates this species has long been targeted by humans for food, with the native Indians
Indigenous peoples of the Americas
The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...
of the region often taking the bar jack for consumption, although it was of lesser importance than reef fishes such as parrotfishes and grouper
Grouper
Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes.Not all serranids are called groupers; the family also includes the sea basses. The common name grouper is usually given to fish in one of two large genera: Epinephelus...
s. Modern fisheries take considerable quantities of the fish, but it rarely makes up the bulk of the catch. Catch statistics are not available for most countries. The United States reports only a small catch of between 0 and 15 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s per year, but with the abundance of the species 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...
, larger catches are made here. The bar jack is somewhat shy of baited hooks
Fish hook
A fish hook is a device for catching fish either by impaling them in the mouth or, more rarely, by snagging the body of the fish. Fish hooks have been employed for centuries by fishermen to catch fresh and saltwater fish. In 2005, the fish hook was chosen by Forbes as one of the top twenty tools...
and is therefore taken predominantly by trawls and seines. It is marketed fresh in the Antilles
Antilles
The Antilles islands form the greater part of the West Indies in the Caribbean Sea. The Antilles are divided into two major groups: the "Greater Antilles" to the north and west, including the larger islands of Cuba, Jamaica, Hispaniola , and Puerto Rico; and the smaller "Lesser Antilles" on the...
and Bahamas, with its edibility
Fish (food)
Fish is a food consumed by many species, including humans. The word "fish" refers to both the animal and to the food prepared from it. Fish has been an important source of protein for humans throughout recorded history.-Terminology:...
rated fair to very good.
The bar jack is a popular light tackle game fish
Game fish
Game fish are fish pursued for sport by recreational anglers. They can be freshwater or marine fish. Game fish can be eaten after being caught, though increasingly anglers practise catch and release to improve fish populations. Some game fish are also targeted commercially, particularly...
, taken predominantly on small lures
Fishing lure
A fishing lure is an object attached to the end of a fishing line which is designed to resemble and move like the prey of a fish. The purpose of the lure is to use movement, vibration, and colour to catch the fish's attention so it bites the hook...
and flies
Fly fishing
Fly fishing is an angling method in which an artificial 'fly' is used to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. Casting a nearly weightless fly or 'lure' requires casting techniques significantly different from other forms of casting...
, with the species considered to be an excellent fighter on light tackle. The species is often sighted working small baitfish to the surface, where they can be targeted with surface poppers or various fly patterns. As mentioned previously, they rarely take baited hooks. The species is often used as bait for larger game fish such as marlin and sailfish
Sailfish
'Sailfish' are two species of fish in the genus Istiophorus, living in warmer sections of all the oceans of the world. They are predominately blue to gray in color and have a characteristic erectile dorsal fin known as a sail, which often stretches the entire length of the back...
.
The bar jack has a significant risk of carrying the 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...
toxin in its flesh, and numerous reports of people contracting the poisoning after consuming the fish. A comprehensive study of the toxin in the West Indies listed the bar jack as a species of intermediate risk of carrying the toxin,
although most cases in St. Thomas
Saint Thomas, U.S. Virgin Islands
Saint Thomas is an island in the Caribbean Sea and with the islands of Saint John, Saint Croix, and Water Island a county and constituent district of the United States Virgin Islands , an unincorporated territory of the United States. Located on the island is the territorial capital and port of...
of the Virgin Islands
Virgin Islands
The Virgin Islands are the western island group of the Leeward Islands, which are the northern part of the Lesser Antilles, which form the border between the Caribbean Sea and the Atlantic Ocean...
can be traced back to the bar jack.