Golden trevally
Encyclopedia
The golden trevally is a tropical marine fish in the jack family (Carangidae
). Native to the eastern Pacific Ocean
from southern California
to Ecuador
, it is associated with reef
s and usually found within the upper ten m (30 ft) of the surface. Juveniles are usually bright yellow with vertical black bars, which alternate between broad and narrow. In adults this coloration fades to a silvery color with the bars faint or absent.
Golden trevally are schooling fish which often follow other large fish, such as shark
s, as well as SCUBA divers
, for protection from predators. They feed on small fishes and on benthic crustaceans and other invertebrates. Juvenile individuals may be found living in the tentacles of jellyfish
.
Juvenile golden trevally may be found in the aquarium trade due to their bright coloration. Adults may be used as food fish.
genus Gnathanodon, which is one of the thirty genera in the jack and horse mackerel family Carangidae
, a group of perciform fishes in the suborder Percoidei
.
The species was scientifically described
for the first time by the Swedish naturalist
Peter Forsskål
in 1775. Forsskål referred the species to the genus Scomber
, where many jacks were placed before the recognition of the family Carangidae. The species is initially referred with two epithets; Scomber rim, speciosus in this publication; however the following page names it as Scomber speciosus with 'rim' given as a transcription of the species' Arabic name. Consequently, authorities regard Scomber rim as a junior synonym. Forsskål's description was based on an individual from the Red Sea
off Jeddah
, Saudi Arabia
. The holotype
has since been lost and a neotype was invalidly designated by Ronald Fricke in 1999. The specific epithet speciosus is Latin for beautiful. The species was transferred to Caranx
before the Dutch
ichthyologist Pieter Bleeker
placed it in its own genus Gnathanodon, with this name derived from the Latin for 'toothless jaws'. In addition to Forsskål's naming, seven other later names have been ascribed to the fish, with all of these now recognised as invalid junior synonyms under ICZN
rules. The species common names generally refer to its appearance with 'golden trevally' (or kingfish), 'banded trevally' and 'king trevally' used. In Hawaii the species is referred to as the 'yellow ulua' or 'papio'.
A study on the phylogenetic relationships of the Carangidae based primarily on osteology
by Soko Gushiken found that Gnathanodon is closely related to and forms a monophyletic group with Caranx. The species has yet to be included in any molecular phylogeny study of the family.
in weight. It is similar to most other trevallies and jacks in having a compressed, oblong
body, with the dorsal profile slightly more convex than the ventral profile, particularly anteriorly. The species' mouth
is one of its defining features; the mouth is highly protractile and fleshy, with specimens greater than 90 mm having no teeth on the jaw
s, vomer
or tongue
. Smaller individuals have a series of small villiform teeth in both jaws. The dorsal fin
is in two parts, the first with 7 spines, the second with 1 spine and 18 to 20 soft rays. The anal fin has 2 detached spines followed by 1 spine and 15 to 17 soft rays, while the pelvic fin consists of 1 spine and 19 to 20 soft rays. The curved part of the lateral line
is moderately arched; containing 62 to 73 scales
, and approximately equal in length to the straight section containing 15 to 27 scales and 18 to 25 scute
s. The breast is completely scaled. There are 27 to 30 gill raker
s and 24 vertebrae in total.
The golden trevally's colour is the species most prominent distinguishing feature, and for which it acquired its common names. Juveniles are a bright golden yellow colour over their entire body and all fins, with 7 to 11 black vertical
crossbars all over their body. These bars generally alternate between broad and narrow. The caudal fin lobes have dark tips and there is a prominent black edge to the operculum
. As the fish grows, the body becomes more silver to silvery golden and the cross bars fade or disappear, often replaced by dark blotches. The fins remain yellow, often with greenish tinges. The dark edge of the operculum also fades with age.
The golden trevally is widely distributed throughout the tropical and subtropical waters of the Indian
and Pacific Ocean
s. In the Indian Ocean, the species is distributed from South Africa
along the east African coastline, including the Red Sea
and Persian Gulf
. Its distribution extends east along the India
n and South East Asian coastlines, and south through Indonesia
and northern Australia
. Golden trevally are recorded from many Indian Ocean islands including Madagascar
, The Seychelles and The Maldives. In the Pacific, the species is spread throughout the South East Asian and Indonesian archipelago north mainland China
and Japan
and south to eastern Australia and New Zealand
. Golden trevally have been recorded from many central Pacific Islands, including Hawaii
, with their distribution extending to central America
. Here its range extends from the Gulf of California
in the north to Colombia
in the south.
The golden trevally predominantly occupies inshore waters of varying substrate, although is know to occur on deeper continental shelf
reef
s in Australia. In coastal areas the species inhabits rocky and coral reef
s as well as open sand flats where it forages for food. A systematic study in northern Australia indicated it to be one of the only species to be approximately equally distributed in both reef and soft-bottom habitats. Golden trevally appear to prefer clear water to turbid waters, and thus is only encountered rarely in low turbidity estuarine environments. One known exception to this was the capture of several individuals in a shallow mangrove swamp in Baja California
which appeared to be foraging for prey.
s as an adult. Juveniles tend to form larger schools which tend to congregate and follow ( or "pilot") larger fish such as grouper
s, shark
s and even jellyfish
. This behaviour mimics that of the related pilot fish
, Naucrates ductor, with their maneuverability protecting from their host which in turn provides them with protection from predation
from other fish. This behaviour extends to scuba
divers, with one diver reporting a single young individual obsessively stationing itself in front of his face plate.
The golden trevally is a diurnal foraging carnivore
which, unlike other carangids, does not normally seek out individual prey items. The highly protractile mouth possessed by the species is used to form a tube to suck prey out of both reef and algae
dominated habitats as well as filtering organisms out of sandy substrates. In the former case, both sand and any prey items are taken into the mouth and filtered through the gill rakers; sand is expelled, while small organisms are trapped and swallowed. The species takes a variety of prey including crustacean
s such as shrimp
s, crab
s and amphipods, as well as molluscs and small fish. Golden trevally found inhabiting a mangrove swamp were found to have fed exclusively on fish (Mugil curema), suggesting the species also actively hunts down fleeing prey. A laboratory study utilising only four individuals being fed found that one fish will take the 'lead' position in this situation while another will attack the other fish in the school, apparently in competition for food.
A variety of parasites have been recorded from the species, including copepod
s, flatworm
s, and a nematode
which inhabits the fish's swimbladder.
Reproduction in the golden trevally has been studied in both the Indian and Pacific Oceans. In the Pacific this was in Hawaii, where it was found spawning
occurred from late February to early October, with a peak from late April to early September. Five distinct peaks during this time were correlated with the first and third quarters of the moon. Spawning occurred from the early evening into the night. In the Indian Ocean, the research was conducted in southern Persian Gulf. Here it was found spawning occurred in April and May, with defined peaks in recruitment
of juveniles into the local fishery
during September and October. The male:female sex ratio
in this population was 1:1.01, close to parity. Growth rates were also studied using otolith
s in this population, with an increase in growth rate during the winter months (November to April). Von Bertalanffy growth curve
s were also calculated for the species.
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...
). Native to the eastern 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...
from southern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
to Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, it is associated with reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s and usually found within the upper ten m (30 ft) of the surface. Juveniles are usually bright yellow with vertical black bars, which alternate between broad and narrow. In adults this coloration fades to a silvery color with the bars faint or absent.
Golden trevally are schooling fish which often follow other large fish, such as shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, as well as SCUBA divers
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
, for protection from predators. They feed on small fishes and on benthic crustaceans and other invertebrates. Juvenile individuals may be found living in the tentacles of jellyfish
Jellyfish
Jellyfish are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria...
.
Juvenile golden trevally may be found in the aquarium trade due to their bright coloration. Adults may be used as food fish.
Taxonomy and phylogeny
The golden trevally is the only member of the monotypicMonotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus Gnathanodon, which is one of the thirty genera in 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...
, a group of perciform 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 scientifically described
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
for the first time by the Swedish 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. Forsskål referred the species to the 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....
, where many jacks were placed before the recognition of the family Carangidae. The species is initially referred with two epithets; Scomber rim, speciosus in this publication; however the following page names it as Scomber speciosus with 'rim' given as a transcription of the species' Arabic name. Consequently, authorities regard Scomber rim as a junior synonym. Forsskål's description was based on an individual 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...
off Jeddah
Jeddah
Jeddah, Jiddah, Jidda, or Jedda is a city located on the coast of the Red Sea and is the major urban center of western Saudi Arabia. It is the largest city in Makkah Province, the largest sea port on the Red Sea, and the second largest city in Saudi Arabia after the capital city, Riyadh. The...
, Saudi Arabia
Saudi Arabia
The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...
. 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...
has since been lost and a neotype was invalidly designated by Ronald Fricke in 1999. The specific epithet speciosus is Latin for beautiful. The species was transferred to 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...
before the Dutch
Dutch people
The Dutch people are an ethnic group native to the Netherlands. They share a common culture and speak the Dutch language. Dutch people and their descendants are found in migrant communities worldwide, notably in Suriname, Chile, Brazil, Canada, Australia, South Africa, New Zealand, and the United...
ichthyologist 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....
placed it in its own genus Gnathanodon, with this name derived from the Latin for 'toothless jaws'. In addition to Forsskål's naming, seven other later names have been ascribed to the fish, with all of these now recognised as invalid junior synonyms under 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. The species common names generally refer to its appearance with 'golden trevally' (or kingfish), 'banded trevally' and 'king trevally' used. In Hawaii the species is referred to as the 'yellow ulua' or 'papio'.
A study on the phylogenetic relationships of the Carangidae based primarily on osteology
Osteology
Osteology is the scientific study of bones. A subdiscipline of anatomy, anthropology, and archeology, osteology is a detailed study of the structure of bones, skeletal elements, teeth, morphology, function, disease, pathology, the process of ossification , the resistance and hardness of bones , etc...
by Soko Gushiken found that Gnathanodon is closely related to and forms a monophyletic group with Caranx. The species has yet to be included in any molecular phylogeny study of the family.
Description
The golden trevally is a relatively large fish, growing to a maximum recorded size of 120 cm in length and 15.0 kgKilogram
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...
in weight. It is similar to most other trevallies and jacks in having a compressed, oblong
Oval
An oval is any curve resembling an egg or an ellipse, such as a Cassini oval. The term does not have a precise mathematical definition except in one area oval , but it may also refer to:* A sporting arena of oval shape** a cricket field...
body, with the dorsal profile slightly more convex than the ventral profile, particularly anteriorly. The species' mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
is one of its defining features; the mouth is highly protractile and fleshy, with specimens greater than 90 mm having no teeth on 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...
s, vomer
Vomer
The vomer is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones.-Biology:...
or tongue
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
. Smaller individuals have a series of small villiform teeth in both jaws. 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 with 7 spines, the second with 1 spine and 18 to 20 soft rays. The anal fin has 2 detached spines followed by 1 spine and 15 to 17 soft rays, while the pelvic fin consists of 1 spine and 19 to 20 soft rays. The curved part of 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...
is moderately arched; containing 62 to 73 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...
, and approximately equal in length to the straight section containing 15 to 27 scales and 18 to 25 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 breast is completely scaled. There are 27 to 30 gill raker
Gill raker
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch and are involved with filter feeding tiny prey. They are not to be confused with the gill filaments that compose the bony part of the gill. Rakers are usually present in two rows, projecting from both the...
s and 24 vertebrae in total.
The golden trevally's colour is the species most prominent distinguishing feature, and for which it acquired its common names. Juveniles are a bright golden yellow colour over their entire body and all fins, with 7 to 11 black 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...
crossbars all over their body. These bars generally alternate between broad and narrow. The caudal fin lobes have dark tips and there is a prominent black edge to 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....
. As the fish grows, the body becomes more silver to silvery golden and the cross bars fade or disappear, often replaced by dark blotches. The fins remain yellow, often with greenish tinges. The dark edge of the operculum also fades with age.
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 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. In the Indian Ocean, the species is distributed 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 African coastline, including 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...
and 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...
. Its distribution extends east along the 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...
n and South East Asian coastlines, and south through 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...
and northern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. Golden trevally are recorded from many Indian Ocean islands including Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, The Seychelles and The Maldives. In the Pacific, the species is spread throughout the South East Asian and Indonesian archipelago north mainland China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and 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...
and south to eastern Australia and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. Golden trevally have been recorded from many central Pacific Islands, including Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, with their distribution extending to 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...
. Here its range extends from the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
in the north to 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...
in the south.
The golden trevally predominantly occupies inshore waters of varying substrate, although is know to occur on deeper 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,...
reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s in Australia. In coastal areas the species inhabits 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 open sand flats where it forages for food. A systematic study in northern Australia indicated it to be one of the only species to be approximately equally distributed in both reef and soft-bottom habitats. Golden trevally appear to prefer clear water to turbid waters, and thus is only encountered rarely in low turbidity estuarine environments. One known exception to this was the capture of several individuals in a shallow mangrove swamp in Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
which appeared to be foraging for prey.
Biology and ecology
The golden trevally is found either as a solitary individual or in small schoolSchool
A school is an institution designed for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is commonly compulsory. In these systems, students progress through a series of schools...
s as an adult. Juveniles tend to form larger schools which tend to congregate and follow ( or "pilot") larger fish such as grouper
Grouper
Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes.Not all serranids are called groupers; the family also includes the sea basses. The common name grouper is usually given to fish in one of two large genera: Epinephelus...
s, shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s and even jellyfish
Jellyfish
Jellyfish are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria...
. This behaviour mimics that of the related pilot fish
Pilot fish
The pilot fish is a carnivorous commensal fish in the family Carangidae. It is widely distributed and lives in warm or tropical open seas.- Description :...
, Naucrates ductor, with their maneuverability protecting from their host which in turn provides them with protection from predation
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...
from other fish. This behaviour extends to scuba
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
divers, with one diver reporting a single young individual obsessively stationing itself in front of his face plate.
The golden trevally is a diurnal foraging carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
which, unlike other carangids, does not normally seek out individual prey items. The highly protractile mouth possessed by the species is used to form a tube to suck prey out of both reef and algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
dominated habitats as well as filtering organisms out of sandy substrates. In the former case, both sand and any prey items are taken into the mouth and filtered through the gill rakers; sand is expelled, while small organisms are trapped and swallowed. The species takes a variety of prey including 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 such as 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 and amphipods, as well as molluscs and small fish. Golden trevally found inhabiting a mangrove swamp were found to have fed exclusively on fish (Mugil curema), suggesting the species also actively hunts down fleeing prey. A laboratory study utilising only four individuals being fed found that one fish will take the 'lead' position in this situation while another will attack the other fish in the school, apparently in competition for food.
A variety of parasites have been recorded from the species, including 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, flatworm
Flatworm
The flatworms, known in scientific literature as Platyhelminthes or Plathelminthes are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrate animals...
s, and a nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
which inhabits the fish's swimbladder.
Reproduction in the golden trevally has been studied in both the Indian and Pacific Oceans. In the Pacific this was in Hawaii, where it was found 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...
occurred from late February to early October, with a peak from late April to early September. Five distinct peaks during this time were correlated with the first and third quarters of the moon. Spawning occurred from the early evening into the night. In the Indian Ocean, the research was conducted in southern Persian Gulf. Here it was found spawning occurred in April and May, with defined peaks in recruitment
Recruitment
Recruitment refers to the process of attracting, screening, and selecting qualified people for a job. For some components of the recruitment process, mid- and large-size organizations often retain professional recruiters or outsource some of the process to recruitment agencies.The recruitment...
of juveniles into the local 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,...
during September and October. The male:female 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....
in this population was 1:1.01, close to parity. Growth rates were also studied using 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...
s in this population, with an increase in growth rate during the winter months (November to April). Von Bertalanffy growth curve
Growth curve
A growth curve is an empirical model of the evolution of a quantity over time. Growth curves are widely used in biology for quantities such as population size, body height or biomass...
s were also calculated for the species.