The blackfin scad (''Alepes melanoptera'') (also known as the shortfinned trevally and Chinese trevally) is a species of

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

marine

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

of the jack family

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 species inhabits inshore waters throughout the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region, although is rare in the western Indian Ocean. It is not a large species, with the largest reported capture being 25 cm, and it is distinguished readily from similar species by the prominent black

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 ...

. It is a predator which feeds on

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

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, but little else is known of its biology. The blackfin scad is a minor

food 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 s ...

throughout its range, and is highly valued in

Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...

and

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

Taxonomy and naming

The blackfin scad is one of five species in the scad genus ''Alepes'', which is one of 33 genera of the jack 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 English

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

William Swainson William Swainson Fellow of the Linnean Society, FLS, Fellow of the Royal Society, FRS (8 October 1789 – 6 December 1855), was an English ornithologist, Malacology, malacologist, Conchology, conchologist, entomologist and artist. Life Swains ...

under the name of ''Trachinus melanoptera'', placing the species in a new genus which was found to be already in use by an unrelated species of fish. The species was therefore subsequently placed in the new combination of ''Alepes melanoptera'', becoming the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

of the new genus ''Alepes''. After Swainson's initial description,

Pieter Bleeker Pieter Bleeker (10 July 1819 – 24 January 1878) was a Dutch medical doctor, Ichthyology, ichthyologist, and Herpetology, herpetologist. He was famous for the ''Atlas Ichthyologique des Indes Orientales Néêrlandaises'', his monumental work on ...

unknowingly redescribed the species as ''Selar malam'', a name which was revised three times before it too was assigned to ''Alepes''. The species was redescribed twice more by Day in 1876 and Chu and Chen in 1958. Being Swainson is the first author to correctly describe the fish, even though he initially ascribed it to the wrong genus, 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 ...

recognises ''Alepes melanoptera'' as the correct name, and the rest as invalid

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

s. Such synonymy is common in the genus ''Alepes'' due to the abundance of similar genera. The specific name 'melanoptera' literally means 'black wing' in Greek; a reference to its distinctive colouration.

Description

The blackfin scad has a body profile very similar to that of the other round scads of the genus ''Alepes'', in particular to '' Alepes apercna'', but can be distinguished quite easily by the prominent black colouration of the

. The species has a tendency, like other carangids, to become more elongated with age, thus changing their body proportions slightly. It has an oblong, compressed body with

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 ...

and

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 ...

profiles that are nearly equally

convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytop ...

in shape. The nose somewhat blunter than others in the genus, and has a mouth full of numerous comb like teeth. Like other members of ''Alepes'', it has an

adipose eyelid An adipose eyelid is a transparent eyelid found in some species of fish, that covers some or all of the eye. They are most commonly found on deep sea (benthic) fish, but can also be seen on non-benthic fish. Fish with this feature include milkfish ...

which is well developed only on the posterior section of the eye. The dorsal fin is split into two sections like in all of the Carangidae, the first with 7 or 8 spines and the second with one spine followed by 23 to 26

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 ...

. 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 ...

consists of two detached spines followed by a single spine and 18 to 21 soft rays, with both the anal and dorsal fins have a low profile. 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 ...

is falcate and extends to beyond the junction of the curved and straight sections of 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 ...

. The lateral line itself is strongly arched anteriorally, with the curved and straight sections of the line intersecting just after the commencement of the spinous dorsal fin. The curved section of the lateral line holds 31 to 50

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 ...

and up to 2

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, while the straight section holds up to 4 scales and 49 to 69 scutes. The

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 number 24 to 30 and the species has 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 blackfin scad has a maximum known length of 25 cm. The upper body of the fish is silvery blue above grading to a silvery white below with a diffuse black spot. The membranes of the first, spinous dorsal fin are black, giving the species its common name. All other fins are pale 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 ...

with the exception of the

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 ...

which is a dusky yellow with darker edges.

Distribution and habitat

The blackfin scad is distributed throughout parts of the

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

region. The species has been recorded as far west as the

Persian Gulf The Persian Gulf, sometimes called the Arabian Gulf, is a Mediterranean seas, mediterranean sea in West Asia. The body of water is an extension of the Arabian Sea and the larger Indian Ocean located between Iran and the Arabian Peninsula.Un ...

(Kuwait) and has a seemingly sparse distribution in the western

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

up to

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, ...

. It is common around the

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

n coast,

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

Philippine The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

s and as far south as

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, ...

. The northernmost captures have been made in

Okinawa, Japan is the southernmost and westernmost prefecture of Japan. It consists of three main island groups—the Okinawa Islands, the Sakishima Islands, and the Daitō Islands—spread across a maritime zone approximately 1,000 kilometers east to west ...

and a specimen has also been collected off

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 ...

. The species frequents inshore habitats, not found in the open ocean.

Biology and fisheries

The biology and ecology of the blackfin scad are poorly studied, although the diet of the species is known. The species is a

planktivorous A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and i ...

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

, consuming a variety of pelagic

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 ...

prawn Prawn is a common name for small aquatic crustaceans with an exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the intern ...

s and

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s. The species is caught mainly by hook and line methods but is not considered a major commercial species in any regions. Despite this, the fish is highly esteemed in

and Thailand, where it is fried,

steamed Steaming is a method of cooking using steam. This is often done with a food steamer, a kitchen appliance made specifically to cook food with steam, but food can also be steamed in a wok. In the American Southwest, steam pits used for cooking ha ...

baked Baking is a method of preparing food that uses dry heat, typically in an oven, but it can also be done in hot ashes, or on hot stones. Bread is the most commonly baked item, but many other types of food can also be baked. Heat is gradually t ...

. It may also be salted or dried.

References

External links

Blackfin scad at fishbase
{{Taxonbar, from=Q2706724 Alepes Fish described in 1839