Orangespotted trevally
Encyclopedia
The orangespotted trevally, Carangoides bajad (also known as the gold-spotted trevally) is a species
of inshore marine
fish
in the jack family, Carangidae
. The species is fairly common in tropical to subtropical waters of the Indo-Pacific
, ranging from Madagascar
in the west to Japan
in the east, typically inhabiting inshore reef
s. The species has characteristic orange-yellow spots on its sides, although counts of fin rays and scutes are needed to distinguish it from related species with similar colouring. Orangespotted trevally are powerful predators, taking a variety of small fish, nekton
and crustacean
s, and reach sexual maturity at around 25 cm. It is a moderately large fish, reaching a maximum known length of 55 cm. The species is occasionally taken by fishermen throughout its range, and is generally considered to be bycatch. The exception to this is in the southern Persian Gulf
, where it makes up a large proportion of the fishery
.
, a group of fish commonly called jacks and trevallies. Carangoides falls into the jack and horse mackerel family Carangidae
, itself part the order Perciformes
, in the suborder Percoidei
.
The species was first scientifically described by the Swedish
naturalist
Peter Forsskål
in 1775 based on a specimen taken from the Red Sea
which he designated to be the holotype
. The specific epithet is an Arabic name of the fish (although it is now usually applied to a catfish, Bagrus bajad, which Forsskål also named), with the letter "j" transcribing a /j/
sound; Forsskål used this technique to name a number of Red Sea fish species. Forsskål at first gave the new taxon subspecies
status as Scomber ferdau bajad, relating it to the mackerel
s, and especially Scomber ferdau, which would later also be transferred to Carangoides. The taxon was later given a species rank, becoming Scomber bajad, then Caranx bajad, before being transferred to its current position as Carangoides bajad.
The species was also independently renamed three times after Forsskål's description, the first coming from Christian Gottfried Ehrenberg
, who named the species Caranx immaculatus, although he did not accurately publish the name, leading Georges Cuvier
to rename the fish as Caranx auroguttatus in 1833, which was later transferred to Carangoides. In 1871, Carl Benjamin Klunzinger once again proposed a new subspecies (or variety) name for the fish, Caranx fulvoguttatus var. flava. All names except Carangoides bajad are considered to be junior synonyms under the ICZN
rules, and are rendered invalid and not used.
shape, with the dorsal profile more convex than the ventral profile. It is a moderately large fish, growing up to 53 cm in length, although more common below 40 cm. The dorsal profile of the head is quite straight from the snout to the nape
, with an eye diameter smaller than the snout length. Both jaw
s contain narrow bands of villiform teeth, with these bands becoming wider anteriorly. The dorsal fin
is in two parts, the first containing 8 spines and the second of 1 spine followed by 24 to 26 soft rays. The anal fin is similar to the second dorsal fin although slightly shorter, and consists of two anteriorly detached spines followed by 1 spine and 21 to 24 soft rays. Another of the major diagnostic features for the species is the length of the anal fin lobe in comparison to the head length, with C. bajad having a head length longer than the anal fin lobe. The lateral line
has a slight, broad anterior curve, with this curved section being longer than the posterior straight section. The straight section of the lateral line has 14 to 26 scales
followed by 20 to 30 scute
s. The chest of the orangespotted trevally is completely scaled, occasionally having a narrow naked region on the underside near the ventral fins. There are 24 vertebrae and a total of 25 to 43 gill raker
s.
The orangespotted trevally has a silvery grey to brassy coloured body, becoming paler to a silvery white ventrally. There are many conspicuous orange to yellow spots on the sides of the fish, giving the species its name, and make for an easy way to identify the fish in the field. There have been records of a variant which is entirely yellow, although it is thought the fish can rapidly change between its normal colour configuration and this entirely orange-yellow colour. The colour of the fins range from hyaline
to lemon yellow, and there is no dark opercular
spot.
The orangespotted trevally inhabits the tropical to subtropical waters of the Indian
and west Pacific Ocean
s. It is distributed from Madagascar
and the Comoros Islands in the west, northwards to the Red Sea
, the Gulf of Aden
and the Persian Gulf
and probably east toward India
, although there have been few records in this region. It is commonly found from the Gulf of Thailand
to Okinawa, Japan in the east, and southward to Indonesia
, Philippines
and New Britain
. In 2005, it was reported that orangespotted trevally had been caught in the Mediterranean Sea
, indicating they had become Lessepsian migrants, passing through the Suez Canal
to extend their range. This claim has been disputed though, with the source of the report coming under question due to the presence of other species unknown to the Mediterranean shown in the purported photograph.
The orangespotted trevally is a coastal species, most common in inshore waters over rocky and coral reef
s, where it is found both solitary and in schools at depths of 2 to 50 m. They are often observed patrolling the edges of seaward reefs, and have been known to mingle with Parupeneus cyclostomus.
. Orangespotted trevally reach sexual maturity
at 24.7 cm on average, with studies in the Persian Gulf indicating the species main spawning
periods occur between June and September. Whether this differs throughout the species range is currently unknown. The same study also showed the species has a strong seasonal oscillation
in the growth rate, which was fastest during November–April and slowest during the summer May–September.
The orangespotted trevally is occasionally taken throughout its range by hook and line, gill nets, and other artisanal gear, although in most areas is bycatch and does not form a large part of these fisheries. There is one fishery that is highly dependent on the species that exists in the southern Persian Gulf. Here the orangespotted trevally is one of the most common fish found just above the sea floor, and is taken by wire traps and sold fresh at local markets. The combined catch of C. bajad and Gnathanodon speciosus totals around 1100 tonnes per year.
The development of the fishing fleet of the United Arab Emirates
has caused a number of species to be overexploited, but the orangespotted trevally is still being taken at sustainable levels.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of inshore marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
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 species is fairly common in tropical to subtropical waters of the Indo-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...
, ranging from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
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, typically inhabiting inshore reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s. The species has characteristic orange-yellow spots on its sides, although counts of fin rays and scutes are needed to distinguish it from related species with similar colouring. Orangespotted trevally are powerful predators, taking a variety of small fish, nekton
Nekton
Nekton refers to the aggregate of actively swimming aquatic organisms in a body of water able to move independently of water currents....
and 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 reach sexual maturity at around 25 cm. It is a moderately large fish, reaching a maximum known length of 55 cm. The species is occasionally taken by fishermen throughout its range, and is generally considered to be bycatch. The exception to this is in the southern 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...
, where it makes up a large proportion of the fishery
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,...
.
Taxonomy and naming
The orangespotted trevally is classified within the genus CarangoidesCarangoides
Carangoides is a genus of tropical to subtropical marine fishes in the jack family, Carangidae. They are small to large sized, deep bodied fish characterised by a certain gill raker and jaw morphology, often appearing very similar to jacks in the genus Caranx...
, a group of fish commonly called jacks and trevallies. Carangoides falls into the jack and horse mackerel family Carangidae
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
, itself part the order Perciformes
Perciformes
The Perciformes, also called the Percomorphi or Acanthopteri, is one of the largest orders of vertebrates, containing about 40% of all bony fish. Perciformes means perch-like. They belong to the class of ray-finned fish and comprise over 7,000 species found in almost all aquatic environments...
, in the suborder Percoidei
Percoidei
Percoidei is one of eighteen suborders of bony fish in the order Perciformes. Many commercially harvested fish species are contained in this suborder, including the snappers, jacks, whitings, groupers, bass, perches and porgies.-Divisions:...
.
The species was first scientifically described by the Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
Peter Forsskål
Peter Forsskål
Peter Forsskål, sometimes spelled Pehr Forsskål, Peter Forskaol, Petrus Forskål or Pehr Forsskåhl, was a Swedish explorer, orientalist, naturalist and an apostle of Carl Linnaeus.-Early life:...
in 1775 based on a specimen taken from the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
which he designated to be the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
. The specific epithet is an Arabic name of the fish (although it is now usually applied to a catfish, Bagrus bajad, which Forsskål also named), with the letter "j" transcribing a /j/
Palatal approximant
The palatal approximant is a type of consonantal sound used in many spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is '...
sound; Forsskål used this technique to name a number of Red Sea fish species. Forsskål at first gave the new taxon subspecies
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...
status as Scomber ferdau bajad, relating it to the mackerel
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....
s, and especially Scomber ferdau, which would later also be transferred to Carangoides. The taxon was later given a species rank, becoming Scomber bajad, then Caranx bajad, before being transferred to its current position as Carangoides bajad.
The species was also independently renamed three times after Forsskål's description, the first coming from Christian Gottfried Ehrenberg
Christian Gottfried Ehrenberg
Christian Gottfried Ehrenberg , German naturalist, zoologist, comparative anatomist, geologist, and microscopist, was one of the most famous and productive scientists of his time.- Early collections :...
, who named the species Caranx immaculatus, although he did not accurately publish the name, leading 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...
to rename the fish as Caranx auroguttatus in 1833, which was later transferred to Carangoides. In 1871, Carl Benjamin Klunzinger once again proposed a new subspecies (or variety) name for the fish, Caranx fulvoguttatus var. flava. All names except Carangoides bajad are considered to be junior synonyms under 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...
rules, and are rendered invalid and not used.
Description
The orangespotted trevally has the typical body profile of the genus Carangoides, having a moderately deep, compressed oblongRectangle
In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle...
shape, with the dorsal profile more convex than the ventral profile. It is a moderately large fish, growing up to 53 cm in length, although more common below 40 cm. The dorsal profile of the head is quite straight from the snout to the nape
Nape
The nape is the back of the neck. In technical anatomical/medical terminology, the nape is referred to by the word nucha, which also gives the adjective corresponding to "nape" in English, "nuchal"....
, with an eye diameter smaller than the snout length. 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 contain narrow bands of villiform teeth, with these bands becoming wider anteriorly. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
is in two parts, the first containing 8 spines and the second of 1 spine followed by 24 to 26 soft rays. The anal fin is similar to the second dorsal fin although slightly shorter, and consists of two anteriorly detached spines followed by 1 spine and 21 to 24 soft rays. Another of the major diagnostic features for the species is the length of the anal fin lobe in comparison to the head length, with C. bajad having a head length longer than the anal fin lobe. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
has a slight, broad anterior curve, with this curved section being longer than the posterior straight section. The straight section of the lateral line has 14 to 26 scales
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
followed by 20 to 30 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. The chest of the orangespotted trevally is completely scaled, occasionally having a narrow naked region on the underside near the ventral fins. There are 24 vertebrae and a total of 25 to 43 gill raker
Gill raker
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch and are involved with filter feeding tiny prey. They are not to be confused with the gill filaments that compose the bony part of the gill. Rakers are usually present in two rows, projecting from both the...
s.
The orangespotted trevally has a silvery grey to brassy coloured body, becoming paler to a silvery white ventrally. There are many conspicuous orange to yellow spots on the sides of the fish, giving the species its name, and make for an easy way to identify the fish in the field. There have been records of a variant which is entirely yellow, although it is thought the fish can rapidly change between its normal colour configuration and this entirely orange-yellow colour. The colour of the fins range from 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...
to lemon yellow, and 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.
Distribution and habitat
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...
and west Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
s. It is distributed from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
and the Comoros Islands in the west, northwards to the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
, the Gulf of Aden
Gulf of Aden
The Gulf of Aden is located in the Arabian Sea between Yemen, on the south coast of the Arabian Peninsula, and Somalia in the Horn of Africa. In the northwest, it connects with the Red Sea through the Bab-el-Mandeb strait, which is about 20 miles wide....
and 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...
and probably east toward 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...
, although there have been few records in this region. It is commonly found 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 Okinawa, Japan in the east, and southward to 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...
, 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 New Britain
New Britain
New Britain, or Niu Briten, is the largest island in the Bismarck Archipelago of Papua New Guinea. It is separated from the island of New Guinea by the Dampier and Vitiaz Straits and from New Ireland by St. George's Channel...
. In 2005, it was reported that orangespotted trevally had been caught in 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...
, indicating they had become Lessepsian migrants, passing through the Suez Canal
Suez Canal
The Suez Canal , also known by the nickname "The Highway to India", is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869 after 10 years of construction work, it allows water transportation between Europe and Asia without navigation...
to extend their range. This claim has been disputed though, with the source of the report coming under question due to the presence of other species unknown to the Mediterranean shown in the purported photograph.
The orangespotted trevally is a coastal species, most common in inshore waters over 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, where it is found both solitary and in schools at depths of 2 to 50 m. They are often observed patrolling the edges of seaward reefs, and have been known to mingle with Parupeneus cyclostomus.
Biology and fisheries
The orangespotted trevally is a strong-swimming predator that takes a variety of prey including fish, crustaceans and nektonNekton
Nekton refers to the aggregate of actively swimming aquatic organisms in a body of water able to move independently of water currents....
. Orangespotted trevally reach sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at 24.7 cm on average, with studies in the Persian Gulf indicating the species main 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...
periods occur between June and September. Whether this differs throughout the species range is currently unknown. The same study also showed the species has a strong seasonal oscillation
Oscillation
Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes...
in the growth rate, which was fastest during November–April and slowest during the summer May–September.
The orangespotted trevally is occasionally taken throughout its range by hook and line, gill nets, and other artisanal gear, although in most areas is bycatch and does not form a large part of these fisheries. There is one fishery that is highly dependent on the species that exists in the southern Persian Gulf. Here the orangespotted trevally is one of the most common fish found just above the sea floor, and is taken by wire traps and sold fresh at local markets. The combined catch of C. bajad and Gnathanodon speciosus totals around 1100 tonnes per year.
The development of the fishing fleet of the United Arab Emirates
United Arab Emirates
The United Arab Emirates, abbreviated as the UAE, or shortened to "the Emirates", is a state situated in the southeast of the Arabian Peninsula in Western Asia on the Persian Gulf, bordering Oman, and Saudi Arabia, and sharing sea borders with Iraq, Kuwait, Bahrain, Qatar, and Iran.The UAE is a...
has caused a number of species to be overexploited, but the orangespotted trevally is still being taken at sustainable levels.