Brownback trevally
Encyclopedia
The brownback trevally, Carangoides praeustus (also known as the brown-backed trevally), is a species of small inshore marine
fish
classified in the jack family, Carangidae
. The brownback trevally is distributed in two populations through the tropical waters of the Indo-west Pacific
region, ranging from the Persian Gulf
east to India
, South East Asia and the Indonesia
n islands. The species is distinguished from similar species by its completely scaled breast and black-tipped second dorsal fin
, and is known to reach a maximum length of 25 cm. The brownback trevally inhabits inshore waters including bay
s and estuaries, where it preys on demersal crustacean
s and small fish. Other aspects of its biology are poorly known, and it is of minor importance to fisheries, occasionally caught by hook and line or trawls
. William Smith-Vaniz has recently suggested the two distinct populations may actually represent two distinct species.
Carangoides
, one of a number of groups of fish referred to as jacks and trevallies. Carangoides is further classified in the family Carangidae
, itself part of the suborder Percoidei
and the order Perciformes
; the perch-like fishes.
The species was first scientifically described by an unknown author in a publication entitled 'Memoir of the Life and Public Services of Sir Thomas Stamford Raffles', in which a chapter was dedicated to fish specimens Raffles had collected. The author is usually presumed to be the English zoologist Edward Turner Bennett
, but due to a lack of evidence to support this, his name is placed in parentheses as required by the ICZN
code. The species was here published under the name of Caranx praeustus, with the holotype
collected from Sumatra
, Indonesia. This classification was later changed to the genus Carangoides by Pieter Bleeker
, where it has remained. Two junior synonyms have been applied to the species, Caranx ire and Caranx melanostethos, which are invalid under ICZN rules. The species specific epithet praeustus is Latin
; meaning "burnt at the tip", in reference to its black dorsal lobe.
In the last revision of the carangids of the Indo-Pacific, William Smith-Vaniz found that the two separate populations have differing gill raker
counts and breast squamation, leading him to suggest the possibility of these being two separate species. If further study indicates these are two separate species, the name Carangoides ire should be reinstated, as Georges Cuvier
described a fish from this second western Indian Ocean population as Caranx ire.
is in two parts, the first consisting of 8 spines while the second has 1 spine and 21 to 24 soft rays, with both dorsal fins of approximately equal height. The anal fin has two anteriorly detached spines followed by 1 spine and 18 to 20 soft rays. The lateral line
has a moderate anterior arch, with the straight and arched sections being nearly equal in length. The straight part of the lateral line has 4 to 12 scales followed by 23 to 34 scutes. The breast is nearly completely scaled
, occasionally having a partially naked midventral area, which rarely extends the entire length of the breast. In the western population, all individuals have this narrow naked midventral area extending the entire length of the breast. Both jaw
s have an irregular row of small conical teeth, with the upper jaw also having a narrow band of teeth anteriorly. The gill raker
count also varies between the two populations, with the eastern population having 32 to 37 in total, while the western population has 40 to 47. There are 24 vertebrae.
The brownback trevally is silvery blue-grey dorsally, shading to silvery underneath, sometimes with a broad brass
y midlateral zone. There is no dark opercular
spot. The distal area of the second dorsal fin lobe is strongly black, usually with a white tip while the remainder of the fin is dusky. The caudal fin is yellow and all other fins are whitish to hyaline
.
s in the tropical waters of the Indo-west pacific
region. The western population extends from the waters of Iran
in the Persian Gulf
to the Bay of Bengal
off Bangladesh
, with records also from the Maldives
and Sri Lanka
. The eastern population inhabits a wide region in the South East Asian and Indonesia
n region, from the Gulf of Thailand
to Borneo
, Philippines
and Indonesia.
The brownback trevally is a coastal species, inhabiting both rocky and coral reef
s, as well as bay
and estuary
environments. The species prefers calm, sheltered waters.
, and focused on the diets of two species of sillaginids
, with investigations into the trophic relationships of fish in the region. It was found the brownback trevally primarily consumes shrimp
s, with lesser amounts of calanoid copepod
s and small fish also taken. Observations indicate the fish form schools of up to 13 fish, which patrol reefs, and are inquisitive of divers. In Hong Kong
waters, the fish is present from April to October, with a darkening of the fishes colour appearing to indicate spawning
occurs in September at this locality.
The brownback trevally is of minor importance to fisheries throughout its range, often taken as bycatch in various trawling and hook and line operations. It is generally not distinguished from other trevally species, and no catch statistics are reported. It is also often taken by small artisanal fisheries by various inshore fish traps.
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
classified in the jack family, Carangidae
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
. The brownback trevally is distributed in two populations through the tropical waters of the Indo-west Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
region, ranging from 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...
, South East Asia and the Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
n islands. The species is distinguished from similar species by its completely scaled breast and black-tipped second 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...
, and is known to reach a maximum length of 25 cm. The brownback trevally inhabits inshore waters including 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 and estuaries, where it preys on demersal crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and small fish. Other aspects of its biology are poorly known, and it is of minor importance to fisheries, occasionally caught by hook and line or trawls
Trawling
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net that is used for trawling is called a trawl....
. William Smith-Vaniz has recently suggested the two distinct populations may actually represent two distinct species.
Taxonomy and naming
The brownback trevally is classified within 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...
Carangoides
Carangoides
Carangoides is a genus of tropical to subtropical marine fishes in the jack family, Carangidae. They are small to large sized, deep bodied fish characterised by a certain gill raker and jaw morphology, often appearing very similar to jacks in the genus Caranx...
, one of a number of groups of fish referred to as jacks and trevallies. Carangoides is further classified in the family Carangidae
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
, itself part of 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:...
and 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 perch-like fishes.
The species was first scientifically described by an unknown author in a publication entitled 'Memoir of the Life and Public Services of Sir Thomas Stamford Raffles', in which a chapter was dedicated to fish specimens Raffles had collected. The author is usually presumed to be the English zoologist Edward Turner Bennett
Edward Turner Bennett
Edward Turner Bennett was an English zoologist and writer. He was the elder brother of the botanist John Joseph Bennett. Bennett was born at Hackney and practiced as a surgeon, but his chief pursuit was always zoology...
, but due to a lack of evidence to support this, his name is placed in parentheses as required by the ICZN
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
code. The species was here published under the name of Caranx praeustus, with 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...
collected from Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, Indonesia. This classification was later changed to the genus Carangoides by Pieter Bleeker
Pieter Bleeker
Pieter Bleeker was a Dutch medical doctor and ichthyologist, famous for his work on the fishes of East Asia – Atlas Ichthyologique des Orientales Neerlandaises – which was published 1862–1877....
, where it has remained. Two junior synonyms have been applied to the species, Caranx ire and Caranx melanostethos, which are invalid under ICZN rules. The species specific epithet praeustus is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
; meaning "burnt at the tip", in reference to its black dorsal lobe.
In the last revision of the carangids of the Indo-Pacific, William Smith-Vaniz found that the two separate populations have differing 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...
counts and breast squamation, leading him to suggest the possibility of these being two separate species. If further study indicates these are two separate species, the name Carangoides ire should be reinstated, as 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...
described a fish from this second western Indian Ocean population as Caranx ire.
Description
The brownback trevally is a relatively small species of carangid, growing to a maximum recorded length of 25 cm, but is much more common at lengths less than 16 cm. The species has a similar body profile to other trevallies in the same genus, having an elongate, compressed form with the dorsal and ventral profiles approximately equal in convexity. The dorsal finDorsal 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 while the second has 1 spine and 21 to 24 soft rays, with both dorsal fins of approximately equal height. The anal fin has two anteriorly detached spines followed by 1 spine and 18 to 20 soft rays. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
has a moderate anterior arch, with the straight and arched sections being nearly equal in length. The straight part of the lateral line has 4 to 12 scales followed by 23 to 34 scutes. The breast is nearly completely scaled
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
, occasionally having a partially naked midventral area, which rarely extends the entire length of the breast. In the western population, all individuals have this narrow naked midventral area extending the entire length of the breast. Both jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
s have an irregular row of small conical teeth, with the upper jaw also having a narrow band of teeth anteriorly. The 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...
count also varies between the two populations, with the eastern population having 32 to 37 in total, while the western population has 40 to 47. There are 24 vertebrae.
The brownback trevally is silvery blue-grey dorsally, shading to silvery underneath, sometimes with a broad brass
Brass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
y midlateral zone. There is no dark opercular
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....
spot. The distal area of the second dorsal fin lobe is strongly black, usually with a white tip while the remainder of the fin is dusky. The caudal fin is yellow and all other fins are whitish to hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
.
Distribution and habitat
The brownback trevally is distributed in two distinct populationPopulation
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
s in the tropical waters of the Indo-west pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
region. The western population extends from the waters of Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
in 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...
to the Bay of Bengal
Bay of Bengal
The Bay of Bengal , the largest bay in the world, forms the northeastern part of the Indian Ocean. It resembles a triangle in shape, and is bordered mostly by the Eastern Coast of India, southern coast of Bangladesh and Sri Lanka to the west and Burma and the Andaman and Nicobar Islands to the...
off Bangladesh
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
, with records also from the Maldives
Maldives
The Maldives , , officially Republic of Maldives , also referred to as the Maldive Islands, is an island nation in the Indian Ocean formed by a double chain of twenty-six atolls oriented north-south off India's Lakshadweep islands, between Minicoy Island and...
and Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
. The eastern population inhabits a wide region in the South East Asian and Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
n region, from the Gulf of Thailand
Gulf of Thailand
The Gulf of Thailand , also known in to Malays as Teluk Siam literally meant Gulf of Siam, is a shallow arm of the South China Sea.-Geography:...
to Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
, 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...
and Indonesia.
The brownback trevally is a coastal species, inhabiting both rocky and 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, as well as 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...
and estuary
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....
environments. The species prefers calm, sheltered waters.
Biology and fishery
The biology of the brownback trevally is known only from a single research study on its diet, and observational evidence recorded by divers. The study was located in the South China SeaSouth China Sea
The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Singapore and Malacca Straits to the Strait of Taiwan of around...
, and focused on the diets of two species of sillaginids
Sillaginidae
The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fishes in the order Perciformes. The smelt-whitings inhabit a wide region covering much of the Indo-Pacific, from the west coast of Africa east to Japan...
, with investigations into the trophic relationships of fish in the region. It was found the brownback trevally primarily consumes 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, with lesser amounts of calanoid 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 small fish also taken. Observations indicate the fish form schools of up to 13 fish, which patrol reefs, and are inquisitive of divers. In Hong Kong
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
waters, the fish is present from April to October, with a darkening of the fishes colour appearing to indicate spawning
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
occurs in September at this locality.
The brownback trevally is of minor importance to fisheries throughout its range, often taken as bycatch in various trawling and hook and line operations. It is generally not distinguished from other trevally species, and no catch statistics are reported. It is also often taken by small artisanal fisheries by various inshore fish traps.