Cleftbelly trevally
Encyclopedia
The cleftbelly trevally, Atropus atropos (also known as the cleftbelly kingfish, Kuweh trevally and thin crevalle) is a species of tropical
marine
fish
of the jack family, Carangidae
. The species inhabits coastal waters throughout the Indo
-West Pacific region from South Africa
in the west to Japan
in the east, often found near the water's surface. The cleftbelly trevally is the only member of the genus Atropus and is distinguished by a number of anatomical characteristics, with a deep median groove in the belly giving the species its common name
. It is not a large fish, growing to a maximum recorded length of 26.5 cm. Cleftbelly trevally are predatory
fish, taking a variety of small crustacean
s and fish. The species is of minor importance to fisheries
throughout its range.
Atropus, which is one of 31 genera in the jack family
, Carangidae
. The carangids are Perciform
fishes in the suborder Percoidei
.
The species was first scientifically described under the name of Brama atropos by German ichthyologists Marcus Elieser Bloch
and Johann Gottlob Schneider
in the massive 1801 volume of Systema Ichthyologiae iconibus cx illustratum, a document which is the taxonomic
authority for many species. Bloch and Schneider placed the species in the genus Brama, within the pomfret
family. The generic position of the species was revised twice, once being placed in the jack genus, Caranx
, and finally into Atropus. The genus Atropus had been informally created by Georges Cuvier
in 1817 as "Les Atropus", and was formally Latinized
by Lorenz Oken
, thus making him the author of the genus. A. atropos is the type species
of the genus by monotypy. The type specimen was taken from the waters of Pondicherry, India
.
The fact that the generic and specific names differ by a single letter has also led to the misspelling of the species as Atropus atropus in some publications. The species is most commonly referred to in English as the cleftbelly trevally, with other names including cleftbelly kingfish, Kuweh trevally and thin crevalle. It is also occasionally called the 'blackfin jack', but should not be confused with Hemicaranx zelotes, also known by that name.
to above the eye where the profile becomes convex. The eye lacks an adipose eyelid, and the upper jaw has a narrow band of small teeth, while the lower jaw has two or three rows of small teeth which narrow to one row on the sides of the jaw. The ventral profile is concave upwards, with a major distinguishing feature of the species being a deep median groove along the belly, into which the large pelvic fins fold, also encompassing the first two anal fin spines and anus
. The entire chest from underneath the pectoral fins to the base of the pelvic fins is scaleless. There are two separate dorsal fin
s, the first with eight spines and the second with a single spine followed by 19 to 22 soft rays. The anal fin has two detached spines before the major part of the anal fin, which consists of one spine and 17 or 18 soft rays. The pectoral and pelvic fins are both quite long, with the latter extending almost to the anal fin origin. The lateral line
has a moderately strong arch anteriorally which intersects the straight section underneath the fifth to seventh dorsal rays. The straight part of the lateral line has 31-37 scute
s.
There are 24 vertebrae and 29 to 34 total gill raker
s. The species is known to reach 26.5 cm in length, although often encountered below 20 cm.
The cleftbelly trevally is a bluish green on the upper body which fades to silver on the underside of the fish. The membranes of the large pelvic fin are a distinctive black, while the remaining fins are a pale white colour. Juveniles have indistinct dark bands across their bodies, with a black spot becoming more prominent in adults.
The species show sexual dimorphism
in their dorsal fins, with mature males having between 6 and 12 elongated soft rays, strung out into filaments of varying lengths. The anal fin is also has five similar extensions of the soft rays. Females do not show this elongation.
and subtropical waters of the Indo
-West Pacific region. Its range extends from South Africa
along the east Africa
n coast including the Persian Gulf
, east to India
, Southeast Asia
, the Philippines
, Taiwan
and southern Japan
. Some sources state the Persian Gulf as the westernmost point of the species range, but specimens sent to Henry Fowler
from South and eastern Africa in the 1930s show this to be incorrect.
The species inhabit shallow coastal waters, where they swim close to the surface. There has been a report of the species living in areas near estuaries
which empty large flows of fresh water into these areas, indicating the species may be able to live in estuarine environments.
species, preying on small crustacean
s including shrimp
s, copepod
s and decapods
, as well as small fish. Reproduction in the species has not been extensively studied, although early growth has been described in a 1984 article. The study was located in India, and showed the fish grows 12.4 cm in its first year of life, growing slower in its second and third years, adding 7.35 cm and 3.5 cm to its total length respectively in these years. The species reaches sexual maturity
at 21 cm, in the second or third year of its life.
The species is of minor importance to fisheries
throughout its range, taken mainly by trawls, traps and by various hook and line methods.
Tropical fish
Tropical fish include fish found in tropical environments around the world, including both freshwater and salt water species.Tropical fish are popular as aquarium fish, due to their often bright coloration...
marine
Marine biology
Marine biology is the scientific study of organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather...
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...
of 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 species inhabits coastal waters throughout the Indo
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...
-West Pacific region from South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
in the west to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
in the east, often found near the water's surface. The cleftbelly trevally is the only member of the genus Atropus and is distinguished by a number of anatomical characteristics, with a deep median groove in the belly giving the species its 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...
. It is not a large fish, growing to a maximum recorded length of 26.5 cm. Cleftbelly trevally are predatory
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
fish, taking a variety of small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and fish. The species is of minor importance to fisheries
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,...
throughout its range.
Taxonomy and naming
The cleftbelly trevally is the only species in the genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Atropus, which is one of 31 genera in the jack family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, 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 carangids are Perciform
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...
fishes in the suborder Percoidei
Percoidei
Percoidei is one of eighteen suborders of bony fish in the order Perciformes. Many commercially harvested fish species are contained in this suborder, including the snappers, jacks, whitings, groupers, bass, perches and porgies.-Divisions:...
.
The species was first scientifically described under the name of Brama atropos by German ichthyologists Marcus Elieser Bloch
Marcus Elieser Bloch
Marcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...
and Johann Gottlob Schneider
Johann Gottlob Schneider
Johann Gottlob Theaenus Schneider was a German classicist and naturalist.-Biography:Schneider was born at Collm in Saxony...
in the massive 1801 volume of Systema Ichthyologiae iconibus cx illustratum, a document which is the taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
authority for many species. Bloch and Schneider placed the species in the genus Brama, within the pomfret
Pomfret
Pomfret are perciform fishes belonging to the family Bramidae.They are found in the Atlantic, Indian, and Pacific Oceans, and the largest species, the Atlantic pomfret, Brama brama, grows up to long....
family. The generic position of the species was revised twice, once being placed in the jack 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...
, and finally into Atropus. The genus Atropus had been informally created by Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
in 1817 as "Les Atropus", and was formally Latinized
Latinisation (literature)
Latinisation is the practice of rendering a non-Latin name in a Latin style. It is commonly met with for historical personal names, with toponyms, or for the standard binomial nomenclature of the life sciences. It goes further than Romanisation, which is the writing of a word in the Latin alphabet...
by Lorenz Oken
Lorenz Oken
Lorenz Oken was a German naturalist.Oken was born Lorenz Okenfuss in Bohlsbach in Baden and studied natural history and medicine at the universities of Freiburg and Würzburg. He went on to the University of Göttingen, where he became a Privatdozent , and shortened his name to Oken...
, thus making him the author of the genus. A. atropos is 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 by monotypy. The type specimen was taken from the waters of Pondicherry, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
.
The fact that the generic and specific names differ by a single letter has also led to the misspelling of the species as Atropus atropus in some publications. The species is most commonly referred to in English as the cleftbelly trevally, with other names including cleftbelly kingfish, Kuweh trevally and thin crevalle. It is also occasionally called the 'blackfin jack', but should not be confused with Hemicaranx zelotes, also known by that name.
Description
The cleftbelly trevally has a body shape similar in many ways to a number of the larger jacks, with a strongly compressed body almost ovate in shape. The dorsal profile of the head is straight and steep from the tip of the upper jawJaw
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...
to above the eye where the profile becomes convex. The eye lacks an adipose eyelid, and the upper jaw has a narrow band of small teeth, while the lower jaw has two or three rows of small teeth which narrow to one row on the sides of the jaw. The ventral profile is concave upwards, with a major distinguishing feature of the species being a deep median groove along the belly, into which the large pelvic fins fold, also encompassing the first two anal fin spines and anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
. The entire chest from underneath the pectoral fins to the base of the pelvic fins is scaleless. There are two separate 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...
s, the first with eight spines and the second with a single spine followed by 19 to 22 soft rays. The anal fin has two detached spines before the major part of the anal fin, which consists of one spine and 17 or 18 soft rays. The pectoral and pelvic fins are both quite long, with the latter extending almost to the anal fin origin. 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 moderately strong arch anteriorally which intersects the straight section underneath the fifth to seventh dorsal rays. The straight part of the lateral line has 31-37 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.
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 species is known to reach 26.5 cm in length, although often encountered below 20 cm.
The cleftbelly trevally is a bluish green on the upper body which fades to silver on the underside of the fish. The membranes of the large pelvic fin are a distinctive black, while the remaining fins are a pale white colour. Juveniles have indistinct dark bands across their bodies, with a black spot becoming more prominent in adults.
The species show sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in their dorsal fins, with mature males having between 6 and 12 elongated soft rays, strung out into filaments of varying lengths. The anal fin is also has five similar extensions of the soft rays. Females do not show this elongation.
Distribution and habitat
The cleftbelly trevally inhabits the tropicalTropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately N and the Tropic of Capricorn in the southern hemisphere at S; these latitudes correspond to the axial tilt of the Earth...
and subtropical waters of the Indo
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...
-West Pacific region. Its range extends from South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
along the east Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
n coast including the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
, east to India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
and southern Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. Some sources state the Persian Gulf as the westernmost point of the species range, but specimens sent to Henry Fowler
Henry Weed Fowler
Henry Weed Fowler was an American zoologist born in Holmesburg, Pennsylvania.He studied at Stanford University under David Starr Jordan...
from South and eastern Africa in the 1930s show this to be incorrect.
The species inhabit shallow coastal waters, where they swim close to the surface. There has been a report of the species living in areas near estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
which empty large flows of fresh water into these areas, indicating the species may be able to live in estuarine environments.
Biology and fishery
The cleftbelly trevally is a predatoryPredation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
species, preying on small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s including 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, 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 and decapods
Decapoda
The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
, as well as small fish. Reproduction in the species has not been extensively studied, although early growth has been described in a 1984 article. The study was located in India, and showed the fish grows 12.4 cm in its first year of life, growing slower in its second and third years, adding 7.35 cm and 3.5 cm to its total length respectively in these years. 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...
at 21 cm, in the second or third year of its life.
The species is of minor importance to fisheries
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,...
throughout its range, taken mainly by trawls, traps and by various hook and line methods.