Crevalle jack
Encyclopedia
The crevalle jack, Caranx hippos (also known as the common jack, black-tailed trevally, couvalli jack, black cavalli and yellow cavalli) is a common species
of large marine
fish classified within the jack family, Carangidae
. The crevalle jack is distributed across the tropical and temperate
waters of the Atlantic Ocean
, ranging from Nova Scotia, Canada to Uruguay
in the west Atlantic and Portugal
to Angola
in the east Atlantic, including the Mediterranean Sea
. The crevalle jack is distinguishable from similar species by its deep body, fin colouration and a host of more detailed anatomical features including fin ray
and lateral line
scale counts. It is one of the largest fish in the genus Caranx
, growing to a maximum known length of 124 cm and a weight of 32 kg
, although is rare at lengths greater than 60 cm. The crevalle jack inhabits both inshore and offshore
waters to depths of around 350 m, predominantly over reef
s, bays, lagoon
s and occasionally estuaries. Young fish dispersed north by currents in the eastern Atlantic are known to migrate
back to more tropical waters before the onset of winter; however if the fish fail to migrate, mass mortalities occur as the temperature falls below the species tolerance limits.
The crevalle jack is a powerful predatory fish, with extensive studies showing the species consumes a variety of small fish, with invertebrates such as prawn
s, shrimp
s, crab
s, molluscs and cephalopods also of minor importance. Dietary shifts with both age, location and season have been demonstrated, which led some researchers to postulate the species is indiscriminant in its feeding habits. The crevalle jack reaches maturity
at 55 cm in males and 66 cm in females, with spawning
taking place year round, although peaks in activity have been documented in several sites. The larval and juvenile growth has been extensively studied, with the oldest known individual 17 years of age. The crevalle jack is an important species to commercial fisheries throughout its range, with annual catches ranging between 1000 and 30 000 tonne
s over its entire range. It is taken by a variety of netting methods including purse nets, seine
s and gill nets as well as hook and line methods. The crevalle jack is also a revered gamefish, taken both by lures and bait. The species is considered of good to poor quality table fair
is sold fresh, frozen, preserved or as fishmeal or oil
at market. The crevalle jack is closely related to both the Pacific crevalle jack
and the longfin crevalle jack
, the latter of which has been extensively confused with the true crevalle jack until recently.
, 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 species belongs to what William Smith-Vaniz and Ken Carpenter refer to as the Caranx hippos complex, a group of closely related fishes which also includes Caranx caninus (Pacific crevalle jack
) and Caranx fischeri (longfin crevalle jack
).
The crevalle jack was the first species of its genus to be scientifically described and named, and is also the type species
of the genus Caranx. The crevalle jack was described and named in 1766 by the famed Swedish taxonomist Carolus Linnaeus
, based on the holotype
specimen taken from coast of Carolina, USA. He named the species Scomber hippos, placing it in the mackerel genus Scomber
, a practice which was common prior to 1801 when the carangids were not yet recognised as separate from the scombrids. The specific epithet means "horse" in Latin
, with Scomber hippos literally translating in English as "horse mackerel", which has become a common name for many species of carangid. As the state of fish taxonomy progressed, the species was transferred to both Caranx and Carangus, with the name Caranx hippos now accepted. Bernard Germain de Lacépède was the first person to separate the crevalle jack from the mackerels, placing it in its own genus Caranx, although he had redescribed the fish as Caranx carangua, which became the type species of Caranx. As well as Lacepede's renaming, the species has been independently redescribed a total of six times, with all of these names, including Lacepede's, categorised as invalid junior synonyms under ICZN
rules.
There has been extensive discussion in the scientific literature
regarding the possible conspecifity of the Pacific crevalle jack, Caranx caninus, with Caranx hippos. Arguments ranged from the species being conspecific, being subspecific
or being individual species. This led to the creation of two trinomial names; Caranx hippos hippos and Caranx hippos tropicus. The former was an attempt to separate the 'subspecies' on each side of the Americas while the latter was an unnecessary name to divide the Atlantic Caranx hippos into subspecies. The most recent review of the species complex by Smith-Vaniz and Carpenter treated the fish as separate species, citing differences in the development of hyperostosis
and differing anal fin colours as evidence of species status. The species most often used common name
of 'crevalle jack' (or 'jack crevalle') is based on the word 'cavalla', an earlier word used for the jacks. Other names include 'common jack', 'black-tailed trevally', 'couvalli jack', 'black cavalli', 'yellow cavalli' and a host of generic names such as 'horse mackerel' and 'crevalle'.
similar to a number of other deep bodied carangids, having an elongate, moderately compressed body with the dorsal profile more convex than the ventral profile, particularly anteriorly. The eye is covered by a well-developed adipose eyelid, and the posterior extremity of the jaw
is vertically under or past the posterior margin of the eye. The dorsal fin
is in two parts, the first consisting of 8 spines and the second of 1 spine followed by 19 to 21 soft rays. The anal fin consists of 2 anteriorly detached spines followed by 1 spine and 16 or 17 soft rays. The pelvic fins contain 1 spine and 5 soft rays while the pectoral fins contain 20 or 21 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head. The lateral line
has a pronounced and moderately long anterior arch, with the curved section intersecting the straight section midway below the second dorsal fin. The straight section contains 23 to 35 very strong scute
s, with bilateral keels present on the caudal peduncle. The chest is devoid of scales with the exception of a small patch of scales in front of the pelvic fins. 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 teeth. The species has 35 to 42 gill raker
s in total and there are 25 vertebrae present.
In 1972, a crevalle jack was caught by fishermen off South Carolina
which displayed swollen, bulbous mandible
s. These swellings were initially thought to be due to a copepod
parasite, however radiographs and subsequent sectioning found them to be bony in nature. The cause of this calcified connective tissue
is still unknown, and there remains only a single reported case of such an ailment in crevalle jack.
The crevalle jack's colour ranges from brassy green to blue or bluish black dorsally, becoming silvery white or golden ventrally. A dark spot is present on the pectoral fin, with a similar dark to dusky spot present on the upper margin of the operculum
. Juveniles have around five dark vertical
bands on their sides, with these fading at adulthood. The first dorsal fin, pectoral and pelvic fins range from white to dusky, occasionally with golden tinges throughout. The anal fin lobe is bright yellow, with the remainder of the fin ranging from golden to dusky, while the underside of the caudal peduncle often being yellow in adults. The caudal fin itself is also golden to dusky, with the lower lobe often brighter yellow than the upper, with both the lobes often having a black trailing edge.
waters of the Atlantic Ocean
, ranging extensively along both the eastern American coastline and the western Africa
n and Europe
an coastlines. In the western Atlantic, the southernmost record comes from Uruguay
, with the species ranging north along the central America
n coastline, and throughout the Caribbean
and many of the numerous archipelago
s within. The species is found throughout the Greater Antilles
, however it is absent from the leeward Lesser Antilles
, with its distribution being patchy throughout other Caribbean Archipelagos. From the Gulf of Mexico
its distribution extends north along the U.S. coast and as far north as Nova Scotia
in Canada
, also taking in several north-west Atlantic islands. The crevalle jack is also known from Saint Helena Island
in the southern Atlantic Ocean.
In the eastern Atlantic the southernmost record comes from Angola
, with the species distributed north along the west African coastline up to West Sahara and Morocco
, with its distribution also including much of the Mediterranean Sea
. In the Mediterranean, the crevalle jack's range extends as far east as Libya
in the south and Turkey
in the north, and includes most of the northern Mediterranean including Greece
, Italy
and Spain
. The species northernmost record in the eastern Atlantic comes from Portugal
, with the species also known to inhabit many of the north-eastern Atlantic islands including Cape Verde
, Madeira Island, and the Canary Islands
.
Many older publications list the species range as from the eastern Pacific, which now are known to represent the Pacific crevalle jack and is considered a distinct species. There are also often mentions of the species erroneously having circumtropical and Indian Ocean
distributions, with these records probably attributable to similar Indo-Pacific species, namely the blacktip trevally
and giant trevally
. The species distribution overlaps that of the similar longfin crevalle jack in the eastern Atlantic, with careful identification needed to distinguish the two. Within the Atlantic, confusion with both longfin crevalle jack and horse-eye jack
, Caranx latus, have also led to erroneous records being made, with Smith-Vaniz and Carpenter suggesting this occurred in the Mediterranean, and the species may actually be absent from waters north of Mauritania
.
habitats, with larger adults preferring deeper waters than juveniles. In the inshore environment, crevalle jack inhabit shallow flats, sandy bay
s, beach
es, seagrass
beds, shallow reef
complexes and lagoon
s, which may be open or landocked, and may be composites of the aforementioned environments. The species is also known to enter brackish waters with some individuals known to penetrate far upstream, however like most euryhaline
species they generally do not penetrate very far inland.
The salinities
the species has been reported from range from 0% to 49%, indicating the species can adapt to a wide range of waters. Studies in West Africa found marked differences in the sex ratio
s of populations in brackish waters, with females very rarely seen in such environments once they are mature. Research in the coastal waters of Ghana
suggests that the availability of food is the primary control on the species distribution in inshore waters.
Adults that move offshore generally do not leave continental shelf
waters, however still penetrate to depths of 350 m, and possibly deeper. These individuals live on the outer shelf edges, sill reefs and upper slopes of the deep reef, and tend to be more solitary than juveniles. Adults have also been sighted around the large oil rig
platforms throughout the Gulf of Mexico
, where they use the man made structure like a reef to hunt prey. The larva
e and young juveniles of the species live pelagically offshore along the continental shelf and slope, and are also known to congregate around oil platforms, as well as natural floating debris such as sargassum
mats.
and Chiapas, Mexico. Seasonal movements are known from both the American and African coastlines, with both juveniles and adults appearing to migrate
. In North America
, young individuals that are recruited to northern estuaries are known to move to warmer tropical waters at the onset of winter to escape possible hypothermia
. At least one hypothermia driven mass mortality of 200 crevalle jacks has been reported from the Slocum River in Massachusetts
, indicating that low temperature mortality is a major concern for north-ranging groups of the species, with temperatures below 9.0°C apparently being lethal to the fish. This applies not only to river dwelling fish, but marine migrants who linger too long in the temperate regions during winter. In Nigeria, and presumably other parts of Africa, it appears the species seasonally migrates, possibly to take advantage of prey, with the fish arriving in Nigeria during September to November. The species is more active during the day than the night, with larger catches in fisheries taken during the day also. The crevalle jack is a schooling
species for most of its life, forming moderately large to very large fast moving schools. At larger sizes, the fish become more solitary and move to the deeper offshore reefs. Evidence from laboratory studies indicates crevalle jack are able to coordinate their feeding and spawning
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. Field studies have also shown the species increases in abundance with increased levels of DMSP over coral reefs.
s generally being of secondary importance to its diet. Several studies conducted on the species diet over its range have found other aspects of its diet vary widely, including the specific types of prey the species takes and the change in diet with age. The most detailed of these studies was conducted in the southern states of the USA, which showed that the species diet comprised between 74% and 94% fish. The remainder of the diet was various prawn
s, shrimp
s, crab
s, molluscs and stomatopods. The types of fish taken varied throughout the range, with members of Clupeidae
, Sparidae
, Carangidae and Trichiuridae all taken in variable amounts, usually with members of one family dominating the local diet. The percentage of various invertebrates also was highly variable, with penaeid shrimps, portunid crabs, stomatopods and squid
being of importance to different populations. The study also indicated young crevalle jack predominantly take clupeids, adding sparids and later carangids to their diet as they grow larger. The larger individuals also took much higher amounts of invertebrates, and also small quantities of seagrass, indicating larger fish are more opportunistic. This general change in diet with age also seems spatially variable, with young crevalle jack in both Maryland
and Puerto Rica consuming almost exclusively crustaceans including shrimps, crabs (and juvenile tarpon
) in Maryland and harpacticoid copepod
s in Puerto Rica before moving to fish dominated diets later in life. Research in Ghana shows a pattern somewhat intermediate to the previous two locations; adults take larger fish, predominantly Engraulis guineensis and Sardinella eba, while juvenile fish take smaller fishes such as Epiplatys sexfasciatus or juvenile caridian and penaeid shrimps.
The widely variable diet of the species throughout its life stages led to authors in the 1950s and 1960s concluding the species was indiscriminate in its feeding habits, eating whatever was locally available. The diets of the populations in both the southern USA and Ghana also varied quite markedly by season and year, which led to the authors of both these studies agreeing with these earlier conclusions. Recent laboratory studies, however, have shown the species may have preferences for certain sizes of prey. In these experiments, the fish was presented with a range of size classes of the same prey species, Menidia beryllina, with the results showing that crevalle jack prefer to take the smallest size class possible, which contrasts with more aggressive predators such as bluefish
. Both adults and juveniles feed throughout the day, generally becoming inactive at night. During some feeding periods recorded in Ghana, digestion
in the species was so rapid that food becomes unidentifiable within 4 to 5 hours of consumption. The crevalle jack is also an important prey species itself, taken by larger fish such as billfish
and sharks, as well as seabird
s. As well as being preyed on during its adult stage, the spawn of the crevalle jack is known to be eaten by planktivorous organisms, including whale shark
s in the Caribbean.
The crevalle jack reaches sexual maturity
at different lengths in males and females, with estimates suggesting males reaching maturity at 55 cm and 4 to 5 years of age and females at 66 cm and 5 to 6 years of age. Reproduction is thought to occur year round in most areas, although there are peaks in activity. South of Florida
, this period is between March and September, in Cuba
it is April and May, while in Jamaica
no definitive peak has yet been identified. The species also has a protracted spawning
in Ghana, although there is a peak in activity between October and January. Juveniles are also present in lagoons year round in this location, indicating year round spawning and recruitment. The place of spawning also appears to be variable, with the act occurring offshore south of Florida, while in Colombia
and Belize
, they have been observed spawning over inshore reefs and bays. Large aggregations of crevalle jack form prior to spawning, with these schools containing upward of 1000 individuals. Pairs break off from the school to spawn, with one individual turning a much darker colour during this exchange. Once spawning has occurred, the pair rejoin the main school. Fecundity
in the species has been estimated as up to one million eggs, with these being pelagic, and spherical in shape. They have a diameter of 0.7 to 0.9 mm, and contain a pigmented yolk and one yellow oil globule with dark pigment
s. The larvae have been extensively described in the scientific literature
, although the sequence of fin formation is still not well known. Defining features of the larval crevalle jack include a relatively deep body, heavily pigmented head and body as well as more detailed meristic characteristics, with flexion
occurring at 4 to 5 mm in length.
Otolith
and vertebrae studies have proved useful in determining the age and thus growth patterns of the species, with other methods including scale and fin ray sectioning of lesser value. The species otoliths have been the subject of detailed x-ray diffraction studies, which have indicated that biomineralisation
of the otoliths occurs predominantly in the aragonite
phase. Females grow faster than males, reaching 266.5 mm after their first year of life, 364.4 after their second, 370.9 mm after the third and 546.7 after their fifth. A female of 676.6 mm was 9 years old. Males reach 252.4 mm in their first year, 336.2 mm in their second, 363.8 in the third and 510.3 in their fifth. A male of 554 mm was 8 years old. The oldest studied individual was a 934 mm individual of unspecified sex, which was 17 years old. The larvae are pelagic and are found over continental shelf waters and occasionally in the oceanic zone proximal to the continental slope. The larvae are present all year round in the Gulf of Mexico, with a peak in abundance during the summer months due to spawning peaks. While the young juveniles live in the exposed pelagic environment, they use a behaviour called 'piloting' to swim in very close proximity to both larger animals and floating objects such as sargassum
mats, buoys and even boats. By the time juveniles make their way to shore, they may have been dispersed large distances from their initial spawning grounds and may face the challenge of migration to warmer climates during winter if they are to survive as outlined previously. Juveniles use estuaries and seagrass
beds as their main nursery habitats.
s since 1950, with catches since 2000 ranging between 190 and 380 tonnes. Most of the eastern Atlantic catch is from Florida
, although Caribbean fisheries such as Trinidad
take considerable quantities of the fish. The western Atlantic catch statistics do not differentiate longfin crevalle jack from crevalle jack, and thus must be considered a composite dataset. This region only comprises catch data from Angola, Ghana, São Tome
, and Principe
. These catches are much larger than in the east, with hauls of between 1000 and 38 000 tonnes per year recorded since 1950, although catches since 2000 only range between 1900 and 10 200 tonnes. Crevalle jack is taken by a number of fishing methods including haul seine
s, gill nets, purse seines, trawls, handlines and trolling lines. The abundance of the species in Trinidad leads to the fish being taken in several quite different types of fishery; demersal trawls, artisinal gill nets and even beach seines, which illustrates the species importance. In Trinidad, recreational fishermen also may sell their catch, which adds to the overall quantity of fish sold. Crevalle jack is sold at market fresh, frozen, salted
, smoked, and as fishmeal and oil
.
The crevalle jack is a popular and highly regarded gamefish throughout its range, with the recreational catch of the species often exceeding commercial catches. The only amateur catch data available is from the US, which has an annual catch of around 400 to 1000 tonnes per year. In Trinidad, the species is the basis for several fishing tournaments. Crevalle jack are targeted from boats as well as from pier
s and rockwalls by land based anglers. Fishermen often target regions where depth suddenly changes such as channels, holes, reefs or ledges, with strong currents
and eddies favourable. The fish take both live and cut baits as well as a variety of artificial lures
; however when the fish are in feeding mode, they rarely refuse anything they are offered. Popular baits include both live fish such as mullet
and menhaden
, as well as dead or strip baits consisting of fish, squid
or prawns. Crevalle jack readily accept any style of lure including hard bodied spoons, jigs, plugs and poppers as well as flies
and soft rubber lures. There is some evidence based on long term observations that the species favours yellow coloured lures over all others. Tackle is often kept quite light, however heavy monofilament leaders are employed to prevent the fish's teeth abrading the line. Crevalle jack are generally considered quite poor table fare, with selection of younger fish and bleeding upon capture giving the best results. The flesh is very red and dark due to the red muscle of the fish, which makes it somewhat coarse and poor tasting. When pulled from the water this fish snorts in what many people describe as "a pig-like" fashion. The crevalle jack has been implicated in several cases of ciguatera
poisoning, although appears less likely to be a carrier than the horse-eye 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 large marine
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 classified within 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 crevalle jack is distributed across the tropical and temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
waters of 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...
, ranging from Nova Scotia, Canada to Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
in the west Atlantic and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
to Angola
Angola
Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...
in the east Atlantic, including the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
. The crevalle jack is distinguishable from similar species by its deep body, fin colouration and a host of more detailed anatomical features including fin ray
Fish anatomy
Fish anatomy is primarily governed by the physical characteristics of water, which is much denser than air, holds a relatively small amount of dissolved oxygen, and absorbs more light than air does.- Body :...
and 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...
scale counts. It is one of the largest fish 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...
, growing to a maximum known length of 124 cm and a weight of 32 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...
, although is rare at lengths greater than 60 cm. The crevalle jack inhabits both inshore and offshore
Shore
A shore or shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In Physical Oceanography a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore,...
waters to depths of around 350 m, predominantly over reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s, bays, 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 and occasionally estuaries. Young fish dispersed north by currents in the eastern Atlantic are known to migrate
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
back to more tropical waters before the onset of winter; however if the fish fail to migrate, mass mortalities occur as the temperature falls below the species tolerance limits.
The crevalle jack is a powerful predatory fish, with extensive studies showing the species consumes a variety of small fish, with invertebrates such as prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
s, 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...
s, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, molluscs and cephalopods also of minor importance. Dietary shifts with both age, location and season have been demonstrated, which led some researchers to postulate the species is indiscriminant in its feeding habits. The crevalle jack reaches 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 55 cm in males and 66 cm in females, 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 year round, although peaks in activity have been documented in several sites. The larval and juvenile growth has been extensively studied, with the oldest known individual 17 years of age. The crevalle jack is an important species to commercial fisheries throughout its range, with annual catches ranging between 1000 and 30 000 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 over its entire range. It is taken by a variety of netting methods including purse nets, 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 and gill nets as well as hook and line methods. The crevalle jack is also a revered gamefish, taken both by lures and bait. The species is considered of good to poor quality table fair
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:...
is sold fresh, frozen, preserved or as fishmeal or oil
Fish oil
Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid , and docosahexaenoic acid , precursors of certain eicosanoids that are known to reduce inflammation throughout the body, and are thought to have many health benefits.Fish do not...
at market. The crevalle jack is closely related to both the Pacific crevalle jack
Pacific crevalle jack
The Pacific crevalle jack, Caranx caninus, is a species of large marine fish classified in the jack family Carangidae. The Pacific crevalle jack is distributed through the tropical waters of the eastern Pacific Ocean from California in the north to Peru in the south, including several offshore...
and the longfin crevalle jack
Longfin crevalle jack
The longfin crevalle jack, Caranx fischeri, is a recently described species of large marine fish classified in the jack family, Carangidae. It inhabits the subtropical waters of the east Atlantic Ocean, ranging along the African coast from Mauritania south at least to Moçamedes in southern Angola,...
, the latter of which has been extensively confused with the true crevalle jack until recently.
Taxonomy and phylogeny
The crevalle 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 species belongs to what William Smith-Vaniz and Ken Carpenter refer to as the Caranx hippos complex, a group of closely related fishes which also includes Caranx caninus (Pacific crevalle jack
Pacific crevalle jack
The Pacific crevalle jack, Caranx caninus, is a species of large marine fish classified in the jack family Carangidae. The Pacific crevalle jack is distributed through the tropical waters of the eastern Pacific Ocean from California in the north to Peru in the south, including several offshore...
) and Caranx fischeri (longfin crevalle jack
Longfin crevalle jack
The longfin crevalle jack, Caranx fischeri, is a recently described species of large marine fish classified in the jack family, Carangidae. It inhabits the subtropical waters of the east Atlantic Ocean, ranging along the African coast from Mauritania south at least to Moçamedes in southern Angola,...
).
The crevalle jack was the first species of its genus to be scientifically described and named, and is also the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus Caranx. The crevalle jack was described and named in 1766 by the famed Swedish taxonomist Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
, 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 taken from coast of Carolina, USA. He named the species Scomber hippos, placing it in the mackerel 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 practice which was common prior to 1801 when the carangids were not yet recognised as separate from the scombrids. The specific epithet means "horse" in 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...
, with Scomber hippos literally translating in English as "horse mackerel", which has become a common name for many species of carangid. As the state of fish taxonomy progressed, the species was transferred to both Caranx and Carangus, with the name Caranx hippos now accepted. Bernard Germain de Lacépède was the first person to separate the crevalle jack from the mackerels, placing it in its own genus Caranx, although he had redescribed the fish as Caranx carangua, which became the type species of Caranx. As well as Lacepede's renaming, the species has been independently redescribed a total of six times, with all of these names, including Lacepede's, categorised as invalid junior synonyms under 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...
rules.
There has been extensive discussion in the scientific literature
Scientific literature
Scientific literature comprises scientific publications that report original empirical and theoretical work in the natural and social sciences, and within a scientific field is often abbreviated as the literature. Academic publishing is the process of placing the results of one's research into the...
regarding the possible conspecifity of the Pacific crevalle jack, Caranx caninus, with Caranx hippos. Arguments ranged from the species being conspecific, being subspecific
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
or being individual species. This led to the creation of two trinomial names; Caranx hippos hippos and Caranx hippos tropicus. The former was an attempt to separate the 'subspecies' on each side of the Americas while the latter was an unnecessary name to divide the Atlantic Caranx hippos into subspecies. The most recent review of the species complex by Smith-Vaniz and Carpenter treated the fish as separate species, citing differences in the development of hyperostosis
Hyperostosis
Hyperostosis is an excessive growth of bone. It may lead to exostosis. It occurs in many musculoskeletal disorders.-See also:* Infantile cortical hyperostosis* SAPHO syndrome* Hyperostosis frontalis interna...
and differing anal fin colours as evidence of species status. The species most often used 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...
of 'crevalle jack' (or 'jack crevalle') is based on the word 'cavalla', an earlier word used for the jacks. Other names include 'common jack', 'black-tailed trevally', 'couvalli jack', 'black cavalli', 'yellow cavalli' and a host of generic names such as 'horse mackerel' and 'crevalle'.
Description
The crevalle jack is one of the largest members of Caranx, growing to a known maximum length of 124 cm and a weight of 32 kg, although are generally rare at lengths greater than 60 cm. Unverified reports of fish over 150 cm may also be attributable to this species. The crevalle jack is morphologicallyMorphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
similar to a number of other deep bodied carangids, having an elongate, moderately compressed body with the dorsal profile more convex than the ventral profile, particularly anteriorly. The eye is covered by a well-developed adipose eyelid, and the posterior extremity 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...
is vertically under or past the posterior margin of the eye. 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 consisting of 8 spines and the second of 1 spine followed by 19 to 21 soft rays. The anal fin consists of 2 anteriorly detached spines followed by 1 spine and 16 or 17 soft rays. The pelvic fins contain 1 spine and 5 soft rays while the pectoral fins contain 20 or 21 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head. The lateral line
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 midway below the second dorsal fin. The straight section contains 23 to 35 very 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, with bilateral keels present on the caudal peduncle. The chest is devoid of scales with the exception of a small patch of scales in front of the pelvic fins. 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 teeth. The species has 35 to 42 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 25 vertebrae present.
In 1972, a crevalle jack was caught by fishermen off South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
which displayed swollen, bulbous mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
s. These swellings were initially thought to be due to a copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
parasite, however radiographs and subsequent sectioning found them to be bony in nature. The cause of this calcified connective tissue
Connective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
is still unknown, and there remains only a single reported case of such an ailment in crevalle jack.
The crevalle jack's colour ranges from brassy green to blue or bluish black dorsally, becoming silvery white or golden ventrally. A dark spot is present on the pectoral fin, with a similar dark to dusky spot present on the upper margin of the operculum
Operculum (fish)
The operculum of a bony fish is the hard bony flap covering and protecting the gills. In most fish, the rear edge of the operculum roughly marks the division between the head and the body....
. Juveniles have around five dark 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 on their sides, with these fading at adulthood. The first dorsal fin, pectoral and pelvic fins range from white to dusky, occasionally with golden tinges throughout. The anal fin lobe is bright yellow, with the remainder of the fin ranging from golden to dusky, while the underside of the caudal peduncle often being yellow in adults. The caudal fin itself is also golden to dusky, with the lower lobe often brighter yellow than the upper, with both the lobes often having a black trailing edge.
Distribution
The crevalle jack inhabits the tropical and temperateTemperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
waters of 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...
, ranging extensively along both the eastern American coastline and the western 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 Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an coastlines. In the western Atlantic, the southernmost record comes from Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
, with the species ranging north along the central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
n coastline, and throughout 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 many of the numerous archipelago
Archipelago
An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...
s within. The species is found throughout the Greater Antilles
Greater Antilles
The Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...
, however it is absent from the leeward Lesser Antilles
Lesser Antilles
The Lesser Antilles are a long, partly volcanic island arc in the Western Hemisphere. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America...
, with its distribution being patchy throughout other Caribbean Archipelagos. From 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...
its distribution extends north along the U.S. coast and as far north as Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, also taking in several north-west Atlantic islands. The crevalle jack is also known from Saint Helena Island
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 southern Atlantic Ocean.
In the eastern Atlantic the southernmost record comes from Angola
Angola
Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...
, with the species distributed north along the west African coastline up to West Sahara and Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
, with its distribution also including much of the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
. In the Mediterranean, the crevalle jack's range extends as far east as Libya
Libya
Libya is an African country in the Maghreb region of North Africa bordered by the Mediterranean Sea to the north, Egypt to the east, Sudan to the southeast, Chad and Niger to the south, and Algeria and Tunisia to the west....
in the south and Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
in the north, and includes most of the northern Mediterranean including Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
. The species northernmost record in the eastern Atlantic comes from Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
, with the species also known to inhabit many of the north-eastern Atlantic islands including Cape Verde
Cape Verde
The Republic of Cape Verde is an island country, spanning an archipelago of 10 islands located in the central Atlantic Ocean, 570 kilometres off the coast of Western Africa...
, Madeira Island, and the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
.
Many older publications list the species range as from the eastern Pacific, which now are known to represent the Pacific crevalle jack and is considered a distinct species. There are also often mentions of the species erroneously having circumtropical 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...
distributions, with these records probably attributable to similar Indo-Pacific species, namely the blacktip trevally
Blacktip trevally
The blacktip trevally, Caranx heberi , is a species of large marine fish classified in the jack family Carangidae. The blacktip trevally is distributed throughout the tropical to subtropical Indian and West Pacific Oceans, ranging from South Africa in the west to Fiji, Japan and northern Australia...
and giant trevally
Giant trevally
The giant trevally, Caranx ignobilis , is a species of large marine fish classified in the jack family, Carangidae...
. The species distribution overlaps that of the similar longfin crevalle jack in the eastern Atlantic, with careful identification needed to distinguish the two. Within the Atlantic, confusion with both longfin crevalle jack and horse-eye jack
Horse-eye jack
The Horse-eye Jack, Caranx latus, is a gamefish and minor commercial fish in the family Carangidae. It is also known as the Big-eye jack, and is similar in appearance to the Crevalle jack, although the head of a Horse-eye jack is not as blunt...
, Caranx latus, have also led to erroneous records being made, with Smith-Vaniz and Carpenter suggesting this occurred in the Mediterranean, and the species may actually be absent from waters north of Mauritania
Mauritania
Mauritania is a country in the Maghreb and West Africa. It is bordered by the Atlantic Ocean in the west, by Western Sahara in the north, by Algeria in the northeast, by Mali in the east and southeast, and by Senegal in the southwest...
.
Habitat
The crevalle jack lives in both inshore and offshoreShore
A shore or shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In Physical Oceanography a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore,...
habitats, with larger adults preferring deeper waters than juveniles. In the inshore environment, crevalle jack inhabit shallow flats, sandy bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
s, beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
es, seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
beds, shallow reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
complexes and 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, which may be open or landocked, and may be composites of the aforementioned environments. The species is also known to enter brackish waters with some individuals known to penetrate far upstream, however like most euryhaline
Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly which can live in fresh, brackish, or salt water. The European shore crab is an example of a euryhaline invertebrate that can live in salt and brackish water...
species they generally do not penetrate very far inland.
The salinities
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
the species has been reported from range from 0% to 49%, indicating the species can adapt to a wide range of waters. Studies in West Africa found marked differences in the 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 of populations in brackish waters, with females very rarely seen in such environments once they are mature. Research in the coastal waters of Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...
suggests that the availability of food is the primary control on the species distribution in inshore waters.
Adults that move offshore generally do not leave 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,...
waters, however still penetrate to depths of 350 m, and possibly deeper. These individuals live on the outer shelf edges, sill reefs and upper slopes of the deep reef, and tend to be more solitary than juveniles. Adults have also been sighted around the large oil rig
Oil platform
An oil platform, also referred to as an offshore platform or, somewhat incorrectly, oil rig, is a lаrge structure with facilities to drill wells, to extract and process oil and natural gas, and to temporarily store product until it can be brought to shore for refining and marketing...
platforms throughout 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...
, where they use the man made structure like a reef to hunt prey. The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e and young juveniles of the species live pelagically offshore along the continental shelf and slope, and are also known to congregate around oil platforms, as well as natural floating debris such as 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.
Biology and ecology
The crevalle jack is one of most abundant large carangids in the Atlantic Ocean, with at least two systematic studies placing it within the top five most abundant species of that region, namely lagoons in NigeriaNigeria
Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...
and Chiapas, Mexico. Seasonal movements are known from both the American and African coastlines, with both juveniles and adults appearing to migrate
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
. In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, young individuals that are recruited to northern estuaries are known to move to warmer tropical waters at the onset of winter to escape possible hypothermia
Hypothermia
Hypothermia is a condition in which core temperature drops below the required temperature for normal metabolism and body functions which is defined as . Body temperature is usually maintained near a constant level of through biologic homeostasis or thermoregulation...
. At least one hypothermia driven mass mortality of 200 crevalle jacks has been reported from the Slocum River in 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...
, indicating that low temperature mortality is a major concern for north-ranging groups of the species, with temperatures below 9.0°C apparently being lethal to the fish. This applies not only to river dwelling fish, but marine migrants who linger too long in the temperate regions during winter. In Nigeria, and presumably other parts of Africa, it appears the species seasonally migrates, possibly to take advantage of prey, with the fish arriving in Nigeria during September to November. The species is more active during the day than the night, with larger catches in fisheries taken during the day also. The crevalle jack is a schooling
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...
species for most of its life, forming moderately large to very large fast moving schools. At larger sizes, the fish become more solitary and move to the deeper offshore reefs. Evidence from laboratory studies indicates crevalle jack are able to coordinate their feeding and 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...
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. Field studies have also shown the species increases in abundance with increased levels of DMSP over coral reefs.
Diet and feeding
The crevalle jack is a powerful predatory fish which predominantly takes other small fishes as prey at all stages of its life, with various invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s generally being of secondary importance to its diet. Several studies conducted on the species diet over its range have found other aspects of its diet vary widely, including the specific types of prey the species takes and the change in diet with age. The most detailed of these studies was conducted in the southern states of the USA, which showed that the species diet comprised between 74% and 94% fish. The remainder of the diet was various prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
s, 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...
s, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, molluscs and stomatopods. The types of fish taken varied throughout the range, with members of Clupeidae
Clupeidae
Clupeidae is the family of the herrings, shads, sardines, hilsa and menhadens. It includes many of the most important food fishes in the world.-Description and biology:...
, Sparidae
Sparidae
The Sparidae is a family of fish, included in the order Perciformes. The fish of the family are commonly called sea breams and porgies . The sheepshead, scup, and red sea bream are species in this family. They are found in shallow temperate and tropical waters and are bottom-dwelling carnivores....
, Carangidae and Trichiuridae all taken in variable amounts, usually with members of one family dominating the local diet. The percentage of various invertebrates also was highly variable, with penaeid shrimps, portunid crabs, stomatopods and squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
being of importance to different populations. The study also indicated young crevalle jack predominantly take clupeids, adding sparids and later carangids to their diet as they grow larger. The larger individuals also took much higher amounts of invertebrates, and also small quantities of seagrass, indicating larger fish are more opportunistic. This general change in diet with age also seems spatially variable, with young crevalle jack in both Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
and Puerto Rica consuming almost exclusively crustaceans including shrimps, crabs (and juvenile tarpon
Tarpon
Tarpons are large fish of the genus Megalops. There are two species of Megalops, one native to the Atlantic, and the other to the Indo-Pacific oceans.They are the only members of the family Megalopidae.- Species and habitats :...
) in Maryland and harpacticoid copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s in Puerto Rica before moving to fish dominated diets later in life. Research in Ghana shows a pattern somewhat intermediate to the previous two locations; adults take larger fish, predominantly Engraulis guineensis and Sardinella eba, while juvenile fish take smaller fishes such as Epiplatys sexfasciatus or juvenile caridian and penaeid shrimps.
The widely variable diet of the species throughout its life stages led to authors in the 1950s and 1960s concluding the species was indiscriminate in its feeding habits, eating whatever was locally available. The diets of the populations in both the southern USA and Ghana also varied quite markedly by season and year, which led to the authors of both these studies agreeing with these earlier conclusions. Recent laboratory studies, however, have shown the species may have preferences for certain sizes of prey. In these experiments, the fish was presented with a range of size classes of the same prey species, Menidia beryllina, with the results showing that crevalle jack prefer to take the smallest size class possible, which contrasts with more aggressive predators such as bluefish
Bluefish
The bluefish , called tailor in Australia, is a species of popular marine gamefish found in all climates. It is the sole species of the Pomatomidae family....
. Both adults and juveniles feed throughout the day, generally becoming inactive at night. During some feeding periods recorded in Ghana, digestion
Digestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
in the species was so rapid that food becomes unidentifiable within 4 to 5 hours of consumption. The crevalle jack is also an important prey species itself, taken by larger fish such as billfish
Billfish
The term billfish is applied to a number of different large, predatory fish characterised by their large size and their long, sword-like bill. Billfish include the sailfish and marlin, which make up the family Istiophoridae, and the swordfish, sole member of the family Xiphiidae...
and sharks, as well as 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. As well as being preyed on during its adult stage, the spawn of the crevalle jack is known to be eaten by planktivorous organisms, including whale shark
Whale shark
The whale shark, Rhincodon typus, is a slow-moving filter feeding shark, the largest extant fish species. The largest confirmed individual had a length of and a weight of more than , but unconfirmed claims report considerably larger whale sharks...
s in the Caribbean.
Life history
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 different lengths in males and females, with estimates suggesting males reaching maturity at 55 cm and 4 to 5 years of age and females at 66 cm and 5 to 6 years of age. Reproduction is thought to occur year round in most areas, although there are peaks in activity. South of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, this period is between March and September, 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...
it is April and May, 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...
no definitive peak has yet been identified. The species also has a protracted 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...
in Ghana, although there is a peak in activity between October and January. Juveniles are also present in lagoons year round in this location, indicating year round spawning and recruitment. The place of spawning also appears to be variable, with the act occurring offshore south of Florida, while in Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
and 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...
, they have been observed spawning over inshore reefs and bays. Large aggregations of crevalle jack form prior to spawning, with these schools containing upward of 1000 individuals. Pairs break off from the school to spawn, with one individual turning a much darker colour during this exchange. Once spawning has occurred, the pair rejoin the main school. Fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
in the species has been estimated as up to one million eggs, with these being pelagic, and spherical in shape. They have a diameter of 0.7 to 0.9 mm, and contain a pigmented yolk and one yellow oil globule with dark pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
s. The larvae have been extensively described in the scientific literature
Scientific literature
Scientific literature comprises scientific publications that report original empirical and theoretical work in the natural and social sciences, and within a scientific field is often abbreviated as the literature. Academic publishing is the process of placing the results of one's research into the...
, although the sequence of fin formation is still not well known. Defining features of the larval crevalle jack include a relatively deep body, heavily pigmented head and body as well as more detailed meristic characteristics, with 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...
occurring at 4 to 5 mm in length.
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...
and vertebrae studies have proved useful in determining the age and thus growth patterns of the species, with other methods including scale and fin ray sectioning of lesser value. The species otoliths have been the subject of detailed x-ray diffraction studies, which have indicated that biomineralisation
Biomineralisation
Biomineralization is the process by which living organisms produce minerals, often to harden or stiffen existing tissues. Such tissues are called mineralized tissues. It is an extremely widespread phenomenon; all six taxonomic kingdoms contain members that are able to form minerals, and over 60...
of the otoliths occurs predominantly in the aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...
phase. Females grow faster than males, reaching 266.5 mm after their first year of life, 364.4 after their second, 370.9 mm after the third and 546.7 after their fifth. A female of 676.6 mm was 9 years old. Males reach 252.4 mm in their first year, 336.2 mm in their second, 363.8 in the third and 510.3 in their fifth. A male of 554 mm was 8 years old. The oldest studied individual was a 934 mm individual of unspecified sex, which was 17 years old. The larvae are pelagic and are found over continental shelf waters and occasionally in the oceanic zone proximal to the continental slope. The larvae are present all year round in the Gulf of Mexico, with a peak in abundance during the summer months due to spawning peaks. While the young juveniles live in the exposed pelagic environment, they use a behaviour called 'piloting' to swim in very close proximity to both larger animals and floating objects such as 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, buoys and even boats. By the time juveniles make their way to shore, they may have been dispersed large distances from their initial spawning grounds and may face the challenge of migration to warmer climates during winter if they are to survive as outlined previously. Juveniles use estuaries and seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
beds as their main nursery habitats.
Relationship to humans
The crevalle jack is a highly important species to commercial fisheries throughout its range, with the greatest quantity of the species taken from the eastern Atlantic. In some fisheries it is one of the most abundant species and therefore of great importance in these regions. In the Americas the reported annual catch has ranged between 150 and 1300 tonneTonne
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 since 1950, with catches since 2000 ranging between 190 and 380 tonnes. Most of the eastern Atlantic catch is from Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, although Caribbean fisheries such as Trinidad
Trinidad
Trinidad is the larger and more populous of the two major islands and numerous landforms which make up the island nation of Trinidad and Tobago. It is the southernmost island in the Caribbean and lies just off the northeastern coast of Venezuela. With an area of it is also the fifth largest in...
take considerable quantities of the fish. The western Atlantic catch statistics do not differentiate longfin crevalle jack from crevalle jack, and thus must be considered a composite dataset. This region only comprises catch data from Angola, Ghana, São Tome
São Tomé
-Transport:São Tomé is served by São Tomé International Airport with regular flights to Europe and other African Countries.-Climate:São Tomé features a tropical wet and dry climate with a relatively lengthy wet season and a short dry season. The wet season runs from October through May while the...
, and Principe
Príncipe
Príncipe is the northern and smaller of the two major islands of the country of São Tomé and Príncipe lying off the west coast of Africa. It has an area of 136 km² and a population of approximately 5,000. The island is a heavily eroded volcano over three million years old, surrounded by other...
. These catches are much larger than in the east, with hauls of between 1000 and 38 000 tonnes per year recorded since 1950, although catches since 2000 only range between 1900 and 10 200 tonnes. Crevalle jack is taken by a number of fishing methods including haul 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, gill nets, purse seines, trawls, handlines and trolling lines. The abundance of the species in Trinidad leads to the fish being taken in several quite different types of fishery; demersal trawls, artisinal gill nets and even beach seines, which illustrates the species importance. In Trinidad, recreational fishermen also may sell their catch, which adds to the overall quantity of fish sold. Crevalle jack is sold at market fresh, frozen, 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...
, smoked, and as fishmeal and oil
Fish oil
Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid , and docosahexaenoic acid , precursors of certain eicosanoids that are known to reduce inflammation throughout the body, and are thought to have many health benefits.Fish do not...
.
The crevalle jack is a popular and highly regarded gamefish throughout its range, with the recreational catch of the species often exceeding commercial catches. The only amateur catch data available is from the US, which has an annual catch of around 400 to 1000 tonnes per year. In Trinidad, the species is the basis for several fishing tournaments. Crevalle jack are targeted from boats as well as from pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...
s and rockwalls by land based anglers. Fishermen often target regions where depth suddenly changes such as channels, holes, reefs or ledges, with strong currents
Ocean current
An ocean current is a continuous, directed movement of ocean water generated by the forces acting upon this mean flow, such as breaking waves, wind, Coriolis effect, cabbeling, temperature and salinity differences and tides caused by the gravitational pull of the Moon and the Sun...
and eddies favourable. The fish take both live and cut baits as well as a variety of artificial 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...
; however when the fish are in feeding mode, they rarely refuse anything they are offered. Popular baits include both live fish such as mullet
Mullet (fish)
The mullets or grey mullets are a family and order of ray-finned fish found worldwide in coastal temperate and tropical waters, and in some species in fresh water. Mullets have served as an important source of food in Mediterranean Europe since Roman times...
and menhaden
Menhaden
Menhaden, also known as mossbunker, bunker and pogy, are forage fish of the genera Brevoortia and Ethmidium, two genera of marine fish in the family Clupeidae.-Description:...
, as well as dead or strip baits consisting of fish, squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
or prawns. Crevalle jack readily accept any style of lure including hard bodied spoons, jigs, plugs and poppers as well as 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...
and soft rubber lures. There is some evidence based on long term observations that the species favours yellow coloured lures over all others. Tackle is often kept quite light, however heavy monofilament leaders are employed to prevent the fish's teeth abrading the line. Crevalle jack are generally considered quite poor table fare, with selection of younger fish and bleeding upon capture giving the best results. The flesh is very red and dark due to the red muscle of the fish, which makes it somewhat coarse and poor tasting. When pulled from the water this fish snorts in what many people describe as "a pig-like" fashion. The crevalle jack has been implicated in 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, although appears less likely to be a carrier than the horse-eye jack
Horse-eye jack
The Horse-eye Jack, Caranx latus, is a gamefish and minor commercial fish in the family Carangidae. It is also known as the Big-eye jack, and is similar in appearance to the Crevalle jack, although the head of a Horse-eye jack is not as blunt...
.
External links
- Crevalle jack (Caranx hippos) at FishBase
- Crevalle jack (Caranx hippos) at Florida Museum of Natural History Ichthyology Department
- Crevalle jack (Caranx hippos) at e-nature.com
- Crevalle jack (Caranx hippos) at Texas Parks and Wildlife
- Crevalle jack (Caranx hippos) at Lagooner Fishing Guides
- Crevalle jack (Caranx hippos) at Electric Blue Fishing