The island trevally, island jack, thicklip trevally or false bluefin trevally (''Carangoides orthogrammus'') is a widespread species of offshore

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine current power * Marine debris * Marine energy * Marine habitats * Mari ...

fish classified in the jack

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Carangidae The Carangidae are a family of ray-finned fish that includes the jacks, pompanos, jack mackerels, runners, trevallies, and scads. It is the largest of the six families included within the order Carangiformes. Some authorities classify it as the ...

. The island trevally is common through the tropical regions of the

Indian Indian or Indians may refer to: Associated with India * of or related to India ** Indian people ** Indian diaspora ** Languages of India ** Indian English, a dialect of the English language ** Indian cuisine Associated with indigenous peoples o ...

and

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

s, ranging from

Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

and the

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...

in the west to

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

and the

Revillagigedo Islands The Revillagigedo Islands (, ) or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem. They lie approximately from Socorro Island south and southwest of Cabo San Lucas, the sout ...

in the central and eastern Pacific. The species is almost completely absent from the

continental shelves A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

, instead inhabiting offshore islands, where it is found in

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') an ...

s and on

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

systems. It is a moderately large fish, growing to a maximum recorded length of 75 cm and 6.6 kg in weight, and is distinguishable by its angular snout and yellow spots, as well as more detailed anatomical features. The island trevally often moves in small schools, preying on a variety of small fishes and

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s. It is of moderate importance to

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...

throughout its range, often taken by trawls, hook-and-line, and various inshore netting methods, and is sold fresh or salted at market.

Taxonomy and naming

The island trevally is classified within the genus ''

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 ...

'', a group of fish commonly called jacks and trevallies. ''Carangoides'' falls into the jack and horse mackerel family

, the Carangidae are part of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Carangiformes Carangiformes is a large, diverse order of ray-finned fishes within the clade Percomorpha. It is part of a sister clade to the Ovalentaria, alongside its sister group, the Anabantaria (including Anabantiformes and Synbranchiformes). The Cara ...

. The species was first

scientifically described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it diffe ...

by the American

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

Jordan Jordan, officially the Hashemite Kingdom of Jordan, is a country in the Southern Levant region of West Asia. Jordan is bordered by Syria to the north, Iraq to the east, Saudi Arabia to the south, and Israel and the occupied Palestinian ter ...

and Gilbert in 1881 based on a specimen taken from the

, which was designated to be the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

. They named this new species ''Caranx orthogrammus'', placing the species in a closely related genus of jacks, but this was later changed to ''Carangoides'' after further revision of the family had occurred. The species was independently redescribed a number of times, with the fish placed in

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

status twice.

John Treadwell Nichols John Treadwell Nichols (June 11, 1883 – November 10, 1958) was an American ichthyologist and Ornithology, ornithologist. Life and career Nichols was born in Jamaica Plain, Boston, Massachusetts, the son of Mary Blake (Slocum) and John White T ...

considered his ''C. ferdau jordani'' to be separate from ''C. orthogrammus'', or possibly a subspecies of the

blue trevally Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The term ''blue'' generally descr ...

, ''C. ferdau'', and was later transferred to ''C. jordani''. It was also considered a subspecies or a synonym of the bludger, ''C. gymnostethoides'', and was also renamed as ''C. nitidus''. The fish is now considered a separate species, with the subspecies names and the later names rendered invalid under the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its formal author, t ...

naming rules. The species is commonly known as island trevally in reference to its preferred offshore habitat, with the names thicklip trevally and false bluefin trevally also used as descriptive names. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

means "straight lined" in

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

Description

The island trevally is a moderately large fish, growing to a maximum recorded length of 75 cm and 6.61 kg in weight. The species is quite similar to ''C. ferdau'', although the prominent yellow spots serve as a quick identifying feature. The island trevally has a compressed

oblong An oblong is an object longer than it is wide, especially a non-square rectangle. Oblong may also refer to: Places * Oblong, Illinois, a village in the United States * Oblong Township, Crawford County, Illinois, United States * A strip of land ...

shaped body with the

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

profile more convex than the

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

profile and the snout usually being slightly rounded. The

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

is in two sections, the first consisting of eight spines and the second of one spine and 28 to 31

soft rays Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiology co ...

, with the lobe of the second dorsal fin being slightly

falcate The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets) ...

in younger individuals, but is always shorter than the head length. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has two detached spines followed by one spine attached to 24 to 26 soft rays, while the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

has one spine attached to 21 or 22 soft rays. The

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

has a very slight anterior arch, with the intersection of the straight and curved sections between the 15th and 19th soft rays of the dorsal fin. The curved section contains 96 to 106

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...

, while the straight section contains 20 to 30 scales and 21 to 28

scute A scute () or scutum (Latin: ''scutum''; plural: ''scuta'' "Scutum (shield), shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of Bird anatomy#Scales, birds. The ter ...

s. The breast is scaleless ventrally until the origin of pelvic fins, often with a small patch of prepelvic scales. Laterally, this naked area of the breast is separated from the naked base of the

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s by a moderate band of scales. The lips are notably fleshy in adults, with both jaws containing narrow bands of villiform teeth which become

obsolescent Obsolescence is the process of becoming antiquated, out of date, old-fashioned, no longer in general use, or no longer useful, or the condition of being in such a state. When used in a biological sense, it means imperfect or rudimentary when comp ...

with age. There are 28 to 32

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of th ...

s in total and 24

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

. The island trevally is a pale blue-green above, becoming more silvery below, with adults having several quite large, elliptical, yellow to brassy spots scattered on their bodies close to the midline. Nine 9 or 10 dark vertical bars may be on the body from the head to the

caudal peduncle Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. The soft dorsal, anal, and

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

s are a pale brownish- to brilliant-blue, with all other fins being pale green to

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

in colour.

Distribution and habitat

The island trevally is distributed throughout the offshore waters of the tropical and subtropical regions of the

and

s. In the Indian Ocean, it ranges from

on the east coast of Africa north to the

Gulf of Aden The Gulf of Aden (; ) is a deepwater gulf of the Indian Ocean between Yemen to the north, the Arabian Sea to the east, Djibouti to the west, and the Guardafui Channel, the Socotra Archipelago, Puntland in Somalia and Somaliland to the south. ...

, but has not been recorded further north until

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

and

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

. Its range extends throughout

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

, and

northern Australia The unofficial geographic term Northern Australia includes those parts of Queensland and Western Australia north of latitude 26th parallel south, 26° and all of the Northern Territory. Those local government areas of Western Australia and Q ...

in the eastern Indian Ocean. In the Pacific, the species has been recorded from

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, and

to the

off

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

in the eastern Pacific, as well as many Pacific islands. As the species common name partly suggests, the island trevally very rarely is found on the

, instead living around offshore islands formed by

volcanic activity Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...

or isolated slivers of continental material remaining from continental drifting. These islands are often quite large, and have most of the geographical features of the continental environment, including

beaches A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from Rock (geology), rock, such as sand, gravel, shingle beach, shingle, pebbles, etc., or biological s ...

s, and even

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

. The island trevally is known from all of these habitats, as well as slightly deeper seaward reefs up to 50 m deep. In Hawaii, the species is less frequently found inside protected bays, and more often slightly further offshore presumably due to competition with other species. The island trevally is one of a number of carangid species known to be attracted to man-made fish-attracting devices, which are installed to aggregate fish for anglers.

Biology and fishery

The island trevally moves both as a solitary individual or in small

schools A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of ...

through its habitat, with the species often accounting for large proportions of an areas immediate

biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...

when moving in schools. The species' diet consists of small fish species and

s, with studies on their exact diet composition finding these fish take different species and different ratios of prey throughout their range. A study conducted in

New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

found the species consumed 98% fish, with only 1%

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s and

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

, while a large study in Hawaii found it took 64.7% crustaceans including crabs, shrimp, and

stomatopod Mantis shrimp are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 400 million years ago, with more than 520 extant species of mantis shrimp known. All li ...

s, while taking only 32.3% fish consisting of

gobies Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising over 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than in length, and the fam ...

and benthic fishes of the order

Scorpaeniformes The Scorpaeniformes are a diverse Order (biology), order of Actinopterygii, ray-finned fish, including the lionfishes and sculpins, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of spec ...

, as well as 2%

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s. In this setting, the major carangid species in the region apparently alter their diets to reduce

interspecific competition Interspecific competition, in ecology, is a form of competition in which individuals of ''different'' species compete for the same resources in an ecosystem (e.g. food or living space). This can be contrasted with mutualism, a type of symbiosis. ...

, but change this partitioning elsewhere in their range where they co-occur.

Reproduction Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: Asexual reproduction, asexual and Sexual ...

and growth are poorly studied in the species, with only a general estimate of spawning timing of March in the

Solomon Island Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, t ...

s. The island trevally is of moderate importance to

throughout its range, often taken by hook and line,

trawl Trawling is an industrial method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch di ...

s, and various types of artisanal gear. The species is generally only caught as bycatch, with catch numbers often very small in comparison to the target species of the fishery. Throughout most of its range, catch statistics are not kept. The species is marketed fresh, dry, or salted, and is considered a good

table fish Many species of fish are caught by humans and consumed as food in virtually all regions around the world. Their meat has been an important dietary source of protein and other nutrients in the human diet. The English language does not have a sp ...

References

External links

Island trevally at Fishbase
* {{Taxonbar, from=Q602789

island trevally The island trevally, island jack, thicklip trevally or false bluefin trevally (''Carangoides orthogrammus'') is a widespread species of offshore marine (ocean), marine fish classified in the jack Family (biology), family Carangidae. The island tr ...

Marine fish of East Africa Fish of the Pacific Ocean Fish of Hawaii