Yellow jack
Encyclopedia
The yellow jack, Carangoides bartholomaei (also known as coolihoo), 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 south, as well as a number of offshore island
s. The yellow jack can be distinguished from closely related species the length of the jaw
, as well as counts of the rays in the fins. It is a fairly large fish, growing to a recorded maximum length of 1 m, and a weight of at least 14 kg
. Yellow jack inhabit reef
s well offshore, moving either individually or in schools and are predatory fish which primarily take other small fish. Studies in the Caribbean suggest the species reaches sexual maturity
between 23 and 32 cm, and spawn
s in offshore waters from February to October. Yellow jack are of minor economic importance
, taken by both hook and net methods, and are considered to be fair table fish. They are often caught by boat angler
s, although are overlooked for their larger relatives.
, a group of fish commonly called jacks and trevallies. Carangoides falls into the jack and horse mackerel family Carangidae
, itself part the order Perciformes
, in the suborder Percoidei
.
The species was first scientifically described by the famed French taxonomist Georges Cuvier
in 1833, based on the holotype
specimen collected from St. Bartholomew Island
in the West Indies.
Cuvier named this new species Caranx bartholomaei after the island from which the holotype was taken. The genus in which the taxon should be placed has proved contentious, and continues to be today with a number of recent publications placing the species in Carangoides, while others still classify it within Caranx
. This article follows the Fishbase
and ITIS
classification of Carangoides bartholomaei. The species predominant common name, "yellow jack", comes from the colour the species turns as it gets older, with other common names including "coolihoo" and incorrectly, "green jack".
The yellow jack shows the typical body profile of the genus Carangoides, having a moderately deep, compressed elongate shape, with the dorsal profile slightly more convex than the ventral profile. It is a large fish, growing to a known maximum length of 1 m, although more common seen below 45 cm, and a maximum weight of 14 kg. The dorsal profile of the head is slightly curved from the snout to the nape
, with the eye having a moderately well developed adipose eyelid. One of the major diagnostic features is that the upper jaw
does not reach to the interior margin of the eye. Both jaws contain narrow bands of villiform teeth, with these bands becoming wider anteriorly. The dorsal fin
is in two parts, the first containing 7 spines and the second of 1 spine followed by 25 to 28 soft rays. The anal fin is similar to the second dorsal fin, consisting of two anteriorly detached spines followed by 1 spine and 21 to 24 soft rays. The lobes of the dorsal and anal fins are slightly pronounced, and the pectoral fin is falcate, being longer than the head. The lateral line
has a slight, extended anterior curve, with this curved section being longer than the posterior straight section. The straight section of the lateral line has 22 to 28 scute
s, with rest of the body being covered in smooth cycloid scale
s, and the chest being completely scaled. The caudal peduncle has bilateral paired keels present. There are 24 vertebrae and a total of 24 to 30 gill raker
s.
The yellow jack is a pale yellow-green-blue dorsally, becoming silver on the underside. Juveniles show around 5 vertical
bands, which fade to blotches and finally disappear altogether as the fish matures. The fins are all hyaline
in appearance, often with a golden-brown tinge to them. Older fish tend to be more yellow, with large specimens having bright yellow fins.
, ranging on the coast of America from Massachusetts
to Maceio, Brazil. The species range includes hundreds of offshore island
s in the eastern Atlantic, including Bermuda
, the Bahamas, the West Indies and throughout the Caribbean Sea
. Along with the bar jack
, Carangoides ruber, it is only one of two species of Carangoides present in the Atlantic, with all others having Indo-Pacific distributions.
The yellow jack is rarely found in inshore coastal waters, preferring offshore reef
s and islands, or open marine waters over the continental shelf
. Whilst not often seen in shallow waters near the American continent, yellow jack are commonly seen in the sandy shallows of a number of Caribbean islands foraging with other species.
Yellow jack are predatory fish, moving both individually or in small groups, with their main prey being small fish, although observational records also show smaller benthic prey is taken. Yellow jack have been observed in a 'following role', moving around with larger species to take advantage of the commotion caused by the bigger fish, allowing the jack to opportunistically forage
or take scraps left by the larger fish. As well as other teleosts, yellow jack have also been recorded following eel
s, stingray
s and nurse shark
s. In one case, they were observed following a flying gurnard, itself smaller than the jack, that disturbed the substrate
, causing various organisms to be displaced and become available for predation. As well as being 'followers', larger specimens have also been observed as the 'followed' species. The species has also been observed living in close relationships with spinner dolphin
s, feeding off the dolphin's waste products. This behavior has also been observed in a number of other jacks living in the region.
Yellow jacks reach maturity at different times in different locations, with studies around Cuba
showing males reach sexual maturity
at 30 cm and females at 32 cm, while in Jamaica
, males reach sexual maturity at 23 cm. Spawning
takes place in offshore waters between February and October. Observational studies in Belize
have shown that although courtship occurs in pairs, the species is a group spawner, congregating in large balls of around 300 fish, with spawning occurring mostly before sunset. Juveniles live near the surface of the ocean, often hiding amongst large mats of jellyfish
or Sargassum
weed, with a coloration that camouflage
s the fish in the weed. These young fish are often moved long distances by the Gulf Stream
, and this is probably the process responsible for fish found as far north as Massachusetts.
throughout their range, taken by seine
s, trawls and hook and line techniques. They are also caught by recreational fishermen
, with fish baits and lures and often while trolling
, although they are rarely targeted specifically. The species is rated as a fair to good table fish
, and is marketed both fresh and salted. Yellow jack are known to be carriers of ciguatera
around the West Indies, and are classified as a high risk species, with their predatory nature allowing the toxin to accumulate in their flesh. The yellow jack was actually the first species outside of the Pacific Ocean
to be confirmed as carrying ciguatera toxins, although these early studies showed that the toxin was biochemically slightly different than the Pacific strain.
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...
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...
. It is one of only two representatives of its genus present in the 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...
, inhabiting waters off the east coast of the Americas from Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
in the north to 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, as well as a number of offshore 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...
s. The yellow jack can be distinguished from closely related species the length of 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...
, as well as counts of the rays in the fins. It is a fairly large fish, growing to a recorded maximum length of 1 m, and a weight of at least 14 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...
. Yellow jack inhabit reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s well offshore, moving either individually or in schools and are predatory fish which primarily take other small fish. Studies in the Caribbean suggest the species 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...
between 23 and 32 cm, and spawn
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...
s in offshore waters from February to October. Yellow jack are of minor economic importance
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
, taken by both hook and net methods, and are considered to be fair table fish. They are often caught by boat angler
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...
s, although are overlooked for their larger relatives.
Taxonomy and naming
The yellow 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 fish commonly called jacks and trevallies. Carangoides falls into the 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...
, itself part 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...
, 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 species was first scientifically described by the famed French taxonomist 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...
in 1833, based on 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...
specimen collected from St. Bartholomew Island
Saint Barthélemy
Saint Barthélemy , officially the Territorial collectivity of Saint Barthélemy , is an overseas collectivity of France. Often abbreviated to Saint-Barth in French, or St. Barts in English, the indigenous people called the island Ouanalao...
in the West Indies.
Cuvier named this new species Caranx bartholomaei after the island from which the holotype was taken. The genus in which the taxon should be placed has proved contentious, and continues to be today with a number of recent publications placing the species in Carangoides, while others still classify it within 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...
. This article follows the 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...
classification of Carangoides bartholomaei. The species predominant common name, "yellow jack", comes from the colour the species turns as it gets older, with other common names including "coolihoo" and incorrectly, "green jack".
Description
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"....
, with the eye having a moderately well developed adipose eyelid. One of the major diagnostic features is that the upper 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...
does not reach to the interior margin of the eye. Both jaws contain narrow bands of villiform teeth, with these bands becoming wider anteriorly. 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...
is in two parts, the first containing 7 spines and the second of 1 spine followed by 25 to 28 soft rays. The anal fin is similar to the second dorsal fin, consisting of two anteriorly detached spines followed by 1 spine and 21 to 24 soft rays. The lobes of the dorsal and anal fins are slightly pronounced, and the pectoral fin is falcate, being 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 slight, extended anterior curve, with this curved section being longer than the posterior straight section. The straight section of the lateral line has 22 to 28 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 rest of the body being covered in smooth cycloid 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, and the chest being completely scaled. The caudal peduncle has bilateral paired keels present. There are 24 vertebrae and a total of 24 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.
The yellow jack is a pale yellow-green-blue dorsally, becoming silver on the underside. Juveniles show around 5 vertical
Vertical direction
In astronomy, geography, geometry and related sciences and contexts, a direction passing by a given point is said to be vertical if it is locally aligned with the gradient of the gravity field, i.e., with the direction of the gravitational force at that point...
bands, which fade to blotches and finally disappear altogether as the fish matures. The fins are all 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...
in appearance, often with a golden-brown tinge to them. Older fish tend to be more yellow, with large specimens having bright yellow fins.
Distribution and habitat
The yellow jack is distributed throughout the tropical to subtropical 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...
, ranging on the coast of America from Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
to Maceio, Brazil. The species range includes hundreds of offshore 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...
s in the eastern Atlantic, 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...
, the Bahamas, the West Indies and throughout the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
. Along with the bar jack
Bar jack
The bar jack, Carangoides ruber is a common species of inshore marine fish classified in the jack family, Carangidae...
, Carangoides ruber, it is only one of two species of Carangoides present in the Atlantic, with all others having Indo-Pacific distributions.
The yellow jack is rarely found in inshore coastal waters, preferring offshore reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s and islands, or open marine waters over the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
. Whilst not often seen in shallow waters near the American continent, yellow jack are commonly seen in the sandy shallows of a number of Caribbean islands foraging with other species.
Biology
Forage
Forage is plant material eaten by grazing livestock.Historically the term forage has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially...
or take scraps left by the larger fish. As well as other teleosts, yellow jack have also been recorded following eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
s, 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 nurse shark
Nurse shark
The nurse shark, Ginglymostoma cirratum, sometimes referred to as the Nur Shark is a shark in the nurse sharks family, the only member of its genus Ginglymostoma...
s. In one case, they were observed following a flying gurnard, itself smaller than the jack, that disturbed the substrate
Substrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
, causing various organisms to be displaced and become available for predation. As well as being 'followers', larger specimens have also been observed as the 'followed' species. The species has also been observed living in close relationships with spinner dolphin
Spinner Dolphin
The Spinner Dolphin is a small dolphin found in off-shore tropical waters around the world. It is famous for its acrobatic displays in which they spin longitudinally along their axis as they leap through the air.-Taxonomy:...
s, feeding off the dolphin's waste products. This behavior has also been observed in a number of other jacks living in the region.
Yellow jacks reach maturity at different times in different locations, with studies around 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...
showing males 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...
at 30 cm and females at 32 cm, while in 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...
, males reach sexual maturity at 23 cm. 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...
takes place in offshore waters between February and October. Observational studies in Belize
Belize
Belize is a constitutional monarchy and the northernmost country in Central America. Belize has a diverse society, comprising many cultures and languages. Even though Kriol and Spanish are spoken among the population, Belize is the only country in Central America where English is the official...
have shown that although courtship occurs in pairs, the species is a group spawner, congregating in large balls of around 300 fish, with spawning occurring mostly before sunset. Juveniles live near the surface of the ocean, often hiding amongst large mats of jellyfish
Jellyfish
Jellyfish are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria...
or 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...
weed, with a coloration that camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
s the fish in the weed. These young fish are often moved long distances by 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...
, and this is probably the process responsible for fish found as far north as Massachusetts.
Relationship to humans
Yellow jack are a minor commercial speciesFishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
throughout their range, taken by seine
Seine
The Seine is a -long river and an important commercial waterway within the Paris Basin in the north of France. It rises at Saint-Seine near Dijon in northeastern France in the Langres plateau, flowing through Paris and into the English Channel at Le Havre . It is navigable by ocean-going vessels...
s, trawls and hook and line techniques. They are also caught by recreational fishermen
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...
, with fish baits and lures and often while trolling
Troll (angling)
Trolling is a method of fishing where one or more fishing lines, baited with lures or bait fish, are drawn through the water. This may be behind a moving boat, or by slowly winding the line in when fishing from a static position, or even sweeping the line from side-to-side, e.g. when fishing from...
, although they are rarely targeted specifically. The species is rated as a fair to good table fish
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:...
, and is marketed both fresh and salted. Yellow jack are known to be carriers 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...
around the West Indies, and are classified as a high risk species, with their predatory nature allowing the toxin to accumulate in their flesh. The yellow jack was actually the first species outside of the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
to be confirmed as carrying ciguatera toxins, although these early studies showed that the toxin was biochemically slightly different than the Pacific strain.