Torpedo scad
Encyclopedia
The torpedo scad, Megalaspis cordyla (also known as the hardtail scad, finny scad, finletted mackerel scad and cordyla scad), is a species of moderately large marine
fish
classified in the jack and horse mackerel family, Carangidae
. The torpedo scad is distributed throughout the tropical Indo-Pacific
region, ranging from South Africa
in the west to Tonga
in the east, extending to Japan
in the north and Australia
in south. It is a schooling pelagic fish which occupies the surface layers of both inshore and offshore
oceanic waters. The torpedo scad is easily identified by both its 'torpedo' shaped body and a series of detached finlets at the rear of both the dorsal
and anal fins. The largest recorded individual was 80 cm long and weighed 4 kg
, although it is more common at lengths less than 40 cm. It is a predatory species, taking a variety of fish, cephalopod
s and crustacean
s by both active and filter feeding. There is a shift in diet as the species grow, however fish is the dominant prey in all size classes. Torpedo scad reach sexual maturity
at 22 cm in females and 26.4 cm in males, with spawning
occurring between March and July in India
. Significant research into larval
growth and morphometrics
has been carried out in India. The torpedo scad is of major importance to fisheries throughout the Indo-Pacific, including India. Statistics (which exclude India) show the annual catch of the species has risen from 70 000 t
in 1997 to 107 000 t in 2007. The major users of the species from this data are Indonesia
and Malaysia. The torpedo scad is often taken by angler
s, however it is considered only marginal table fare
and is occasionally used as bait.
genus Megalaspis, which is one of the thirty genera in the family Carangidae
, a group of perciform fishes in the suborder Percoidei
.
The species was first scientifically described by Carl Linnaeus, a famed Swedish naturalist
who is widely considered the father of modern taxonomy
. The specimen described by Linnaeus was erroneously described as being from "America", and no holotype
is known for the species. Ronald Frick designated a neotype for the species in 1999, however this was rejected as it failed to satisfy ICZN
regulations. Linnaeus named the species Scomber cordyla, placing the fish in the true mackerel
genus, which was a common practice before the family Carangidae was recognised. The specific epithet is Latin for "mackerel" or "young tunny (tuna)". A second independent renaming of the species occurred in 1793 by Marcus Elieser Bloch
, who assigned the name Scomber rottleri, with several later redescriptions and namings occurring up until 1874. In 1851 Pieter Bleeker
reassigned Scomber rottleri to its own genus Megalaspis, meaning "large scute
s". When S. rottleri was found to be a junior synonym of S. cordyla, the name of the species was finally transferred to Megalaspis cordyla where it has remained. M. cordyla has a variety of common name
s, the most common of which is 'torpedo scad', with 'hardtail scad', 'finny scad', 'finletted mackerel scad' and 'cordyla scad' occasionally used. Because of the wide range of the species, it has a large collection of non-English common names also.
The relationship of the species to other carangids was assessed in Soko Gushiken's 1986 paper on the phylogeny of the Carangidae. It was the sole species in one of three distinct clade
s within the tribe
Carangini. The torpedo scad has not been included in any later genetic phylogenetic studies of the Carangidae.
, however is more common between 30 to 40 cm length. It is rare at lengths greater than 80 cm. The species is often considered to have a rather unusual body form, having features superficially similar to tuna
s, mackerels and other carangids. The body is elongate and subcylindrical, becoming highly compressed toward the tail and caudal fin, with a marked median keel on the caudal peduncle. The dorsal and ventral profiles of the fish are nearly evenly convex, with the two profiles intersecting at the pointed snout. There are two separate dorsal fin
s; the first consisting of 8 moderately high spines and the second of a single spine followed by 18 to 20 soft rays. The anal fin consists of two anteriorally detached spines followed by a single spine attached to 16 or 17 soft rays. In both the dorsal and anal fins, the posterior 7-10 rays are detached and form a series of diagnostic finlets. The pectoral fin is strongly falcate (scythe shaped), and extends beyond the origin of the second dorsal fin. The lateral line
is strongly arched over a short length anteriorly, with the intersection of the curved and straight sections vertically below the fourth or fifth spine of the first dorsal fin. The curved section of the lateral line has 21 to 29 scale
s, while the straight section has 51 to 59 very large scute
s. The breast is devoid of scales in a triangular patch to about one-third the distance to the pectoral fin base. The eye has a well-developed adipose eyelid which nearly completely covers the eye. The upper jaw contains small villiform teeth, with some outer teeth moderately enlarged, while the lower jaw has a single row of small teeth. There are 26 to 32 gill raker
s and 24 vertebrae.
The olfactory apparatus and hypothalamo-neurosecretory system of the species has been extensively described in the Indian scientific literature. Also of note is a report of a heavily deformed individual from India, which survived past maturity.
The torpedo scad is bluish-grey to green above, changing to a silvery white on its sides and belly
. The dorsal and anal fins are pale to yellow, becoming dusky at the outer edges. The pectoral and pelvic fins are also pale with dusky upper halves, while the caudal fin is dark, particularly on the leading and trailing edges. A large black spot is present on the operculum
.
and west Pacific Ocean
s. In the west, the range of the species extends from the tip of South Africa
north along the east African coastline to the Persian Gulf
and Red Sea
. Records of the fish are common from most Indian Ocean islands including the Maldives
, Seychelles
and Madagascar
. The species is found along the India
n and Asia
n coastlines, extending north to China
and South Korea
on the mainland. It is abundant through the central Indo-Pacific and the Indonesian Archipelago, with its offshore range extending to Taiwan
and Japan
in the north. Around Australia
, torpedo scad have been recorded as far south as Fremantle
on the west coast and Sydney
on the east coast. The range of the species extends to several eastern Pacific islands including Samoa
, New Caledonia
and Tonga
.
The torpedo scad is a pelagic schooling
species which is found in both far offshore ocean
ic environments as well as more protected inshore environments. The fish commonly are found in the upper water column near the surface waters. It is not found in estuaries and appears to be intolerant of dirty or turbid waters. The range of the species extends to more southern waters in summer as the warm waters push further down the coasts.
. All of this information is published in relatively obscure Indian journals and is unavailable to most institutions. The torpedo scad is a predatory fish which both consumes larger prey and filter feeds to consume plankton
ic organisms. Larger prey items include a variety of fish and cephalopod
s including squid
and cuttlefish
. Smaller foods are mostly crustacean
s such as shrimp
s, prawn
s, stomatopods, cladocerans and crab
s. Molluscs and gastropods are also reported to be minor constituents of the diet of the species. The species also appears to have dietary shifts as it grows, however in all size classes fish are the dominant prey. Species recorded as being predators of torpedo scad include species of drums
and requiem shark
. Each sex of the torpedo scad reach sexual maturity
at different lengths; females are mature by 22 cm and males by 26.4 cm. Other studies have suggested similar lengths, including 17 cm in males and 27 cm in females, as well as an average of 25 cm in both sexes. Spawning
has not been directly observed, however peaks in larval
abundance are known from March to July, with a peak in June in India. the eggs are pelagic, and are spherical and transparent with a yolk and single oil globule. The larval stage is extensively described, with the species having 24 myomere
s. The growth of the species is not reported, however numerous morphometric (length vs weight) studies have been carried out on the species. The population structure in Indian waters has also been well studied, with the most recent of these suggesting a major recruitment event occurs between May and August. These studies also guide fisheries regulations, with a theoretical maximum yield achieved when fish are only taken once they reach 18 cm.
do not include India, however even without this country the annual take of torpedo scad has increased from 70 000 t
in 1997 to 107 000 t in 2007. On the basis of these statistics, the biggest utiliser of the species is Indonesia, with a take of 42 000 t followed by Malaysia with a take of 22 000 t. Thailand
and the Philippines
also take large quantities of the fish, with around 18 000 t each annually. Middle East
ern countries also record this species in their hauls, but at lower amounts of between 50 and 5000 t. In more southerly regions such as South Africa, it is a rare catch, usually appearing in beach seines. The species is taken by a variety of netting methods such as beach seines, trawls, purse seines and other types of trap including hook and line. It is usually marketed fresh, dried or salted
. Torpedo scad are often caught by recreational fishermen
throughout their range, however are not considered a target for gamefishing. They readily take small lures and are good sport on light tackle. Torpedo scad are said to have fair to good quality flesh
, however are not very popular. Some chefs recommend frying or steaming the fish, although grilling is also acceptable. In polluted waters it has been demonstrated the fish contain higher than acceptable levels of heavy metals
, and should be avoided in such regions. Torpedo scad are often used as live baits for larger gamefish.
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
classified in the jack 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...
. The torpedo scad is distributed throughout the tropical 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...
region, ranging 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...
in the west to Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
in the east, extending 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 north and 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...
in south. It is a schooling pelagic fish which occupies the surface layers of both inshore and offshore
Shore
A shore or shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In Physical Oceanography a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore,...
oceanic waters. The torpedo scad is easily identified by both its 'torpedo' shaped body and a series of detached finlets at the rear of both the dorsal
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
and anal fins. The largest recorded individual was 80 cm long and weighed 4 kg
Kilogram
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...
, although it is more common at lengths less than 40 cm. It is a predatory species, taking a variety of fish, cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s 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 by both active and filter feeding. There is a shift in diet as the species grow, however fish is the dominant prey in all size classes. Torpedo scad 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 22 cm in females and 26.4 cm in males, with 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...
occurring between March and July in 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...
. Significant research into larval
Larvae
In Roman mythology, lemures were shades or spirits of the restless or malignant dead, and are probably cognate with an extended sense of larvae as disturbing or frightening...
growth and morphometrics
Morphometrics
Morphometrics refers to the quantitative analysis of form, a concept that encompasses size and shape. Morphometric analyses are commonly performed on organisms, and are useful in analyzing their fossil record, the impact of mutations on shape, developmental changes in form, covariances between...
has been carried out in India. The torpedo scad is of major importance to fisheries throughout the Indo-Pacific, including India. Statistics (which exclude India) show the annual catch of the species has risen from 70 000 t
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
in 1997 to 107 000 t in 2007. The major users of the species from this data are 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 Malaysia. The torpedo scad is often taken by angler
Angling
Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...
s, however it is considered only marginal table fare
Fish (food)
Fish is a food consumed by many species, including humans. The word "fish" refers to both the animal and to the food prepared from it. Fish has been an important source of protein for humans throughout recorded history.-Terminology:...
and is occasionally used as bait.
Taxonomy and phylogeny
The torpedo scad 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 Megalaspis, which is one of the thirty genera in the family Carangidae
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
, 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 first scientifically described by Carl Linnaeus, a famed Swedish naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
who is widely considered the father of modern taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
. The specimen described by Linnaeus was erroneously described as being from "America", and no 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...
is known for the species. Ronald Frick designated a neotype for the species in 1999, however this was rejected as it failed to satisfy 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...
regulations. Linnaeus named the species Scomber cordyla, placing the fish in the true 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....
genus, which was a common practice before the family Carangidae was recognised. The specific epithet is Latin for "mackerel" or "young tunny (tuna)". A second independent renaming of the species occurred in 1793 by Marcus Elieser Bloch
Marcus Elieser Bloch
Marcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...
, who assigned the name Scomber rottleri, with several later redescriptions and namings occurring up until 1874. In 1851 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....
reassigned Scomber rottleri to its own genus Megalaspis, meaning "large 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". When S. rottleri was found to be a junior synonym of S. cordyla, the name of the species was finally transferred to Megalaspis cordyla where it has remained. M. cordyla has a variety of common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s, the most common of which is 'torpedo scad', with 'hardtail scad', 'finny scad', 'finletted mackerel scad' and 'cordyla scad' occasionally used. Because of the wide range of the species, it has a large collection of non-English common names also.
The relationship of the species to other carangids was assessed in Soko Gushiken's 1986 paper on the phylogeny of the Carangidae. It was the sole species in one of three distinct clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s within the tribe
Tribe
A tribe, viewed historically or developmentally, consists of a social group existing before the development of, or outside of, states.Many anthropologists use the term tribal society to refer to societies organized largely on the basis of kinship, especially corporate descent groups .Some theorists...
Carangini. The torpedo scad has not been included in any later genetic phylogenetic studies of the Carangidae.
Description
The torpedo scad is a moderately large fish, growing to a maximum recorded length of 80 cm and a weight of 4 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...
, however is more common between 30 to 40 cm length. It is rare at lengths greater than 80 cm. The species is often considered to have a rather unusual body form, having features superficially similar to tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...
s, mackerels and other carangids. The body is elongate and subcylindrical, becoming highly compressed toward the tail and caudal fin, with a marked median keel on the caudal peduncle. The dorsal and ventral profiles of the fish are nearly evenly convex, with the two profiles intersecting at the pointed snout. There are two separate 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...
s; the first consisting of 8 moderately high spines and the second of a single spine followed by 18 to 20 soft rays. The anal fin consists of two anteriorally detached spines followed by a single spine attached to 16 or 17 soft rays. In both the dorsal and anal fins, the posterior 7-10 rays are detached and form a series of diagnostic finlets. The pectoral fin is strongly falcate (scythe shaped), and extends beyond the origin of the second dorsal fin. 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 strongly arched over a short length anteriorly, with the intersection of the curved and straight sections vertically below the fourth or fifth spine of the first dorsal fin. The curved section of the lateral line has 21 to 29 scale
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...
s, while the straight section has 51 to 59 very large 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 devoid of scales in a triangular patch to about one-third the distance to the pectoral fin base. The eye has a well-developed adipose eyelid which nearly completely covers the eye. The upper jaw contains small villiform teeth, with some outer teeth moderately enlarged, while the lower jaw has a single row of small teeth. There are 26 to 32 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.
The olfactory apparatus and hypothalamo-neurosecretory system of the species has been extensively described in the Indian scientific literature. Also of note is a report of a heavily deformed individual from India, which survived past maturity.
The torpedo scad is bluish-grey to green above, changing to a silvery white on its sides and belly
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. The dorsal and anal fins are pale to yellow, becoming dusky at the outer edges. The pectoral and pelvic fins are also pale with dusky upper halves, while the caudal fin is dark, particularly on the leading and trailing edges. A large black spot is present on 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....
.
Distribution and habitat
The torpedo scad is distributed throughout the tropical and subtropical waters of the IndianIndian 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. In the west, the range of the species extends from the tip of 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...
north along the east African coastline to 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 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...
. Records of the fish are common from most Indian Ocean islands including the Maldives
Maldives
The Maldives , , officially Republic of Maldives , also referred to as the Maldive Islands, is an island nation in the Indian Ocean formed by a double chain of twenty-six atolls oriented north-south off India's Lakshadweep islands, between Minicoy Island and...
, Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
and Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. The species is found 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 Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n coastlines, extending north to 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 South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
on the mainland. It is abundant through the central Indo-Pacific and the Indonesian Archipelago, with its offshore range extending to Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
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...
in the north. Around 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...
, torpedo scad have been recorded as far south as Fremantle
Fremantle, Western Australia
Fremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...
on the west coast and Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
on the east coast. The range of the species extends to several eastern Pacific islands including Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...
, New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
and Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
.
The torpedo scad is a pelagic schooling
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
species which is found in both far offshore ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
ic environments as well as more protected inshore environments. The fish commonly are found in the upper water column near the surface waters. It is not found in estuaries and appears to be intolerant of dirty or turbid waters. The range of the species extends to more southern waters in summer as the warm waters push further down the coasts.
Biology and ecology
The torpedo scad is an important species to commercial fisheries in parts of Asia, and as such has had significant research published on its biology and ecologyEcology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
. All of this information is published in relatively obscure Indian journals and is unavailable to most institutions. The torpedo scad is a predatory fish which both consumes larger prey and filter feeds to consume plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic organisms. Larger prey items include a variety of fish and cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s including squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
and cuttlefish
Cuttlefish
Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....
. Smaller foods are mostly 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, prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
s, stomatopods, cladocerans and 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. Molluscs and gastropods are also reported to be minor constituents of the diet of the species. The species also appears to have dietary shifts as it grows, however in all size classes fish are the dominant prey. Species recorded as being predators of torpedo scad include species of drums
Sciaenidae
Sciaenidae is a family of fish commonly called drums, croakers, or hardheads for the repetitive throbbing or drumming sounds they make...
and requiem shark
Requiem shark
Requiem sharks are a family, Carcharhinidae, of sharks in the order Carcharhiniformes, containing migratory, live-bearing sharks of warm seas such as the tiger shark, the blue shark, the bull shark, and the milk shark.The name may be related to the French word for shark, "requin", itself of...
. Each sex of the torpedo scad 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 different lengths; females are mature by 22 cm and males by 26.4 cm. Other studies have suggested similar lengths, including 17 cm in males and 27 cm in females, as well as an average of 25 cm in both sexes. 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...
has not been directly observed, however peaks in larval
Larvae
In Roman mythology, lemures were shades or spirits of the restless or malignant dead, and are probably cognate with an extended sense of larvae as disturbing or frightening...
abundance are known from March to July, with a peak in June in India. the eggs are pelagic, and are spherical and transparent with a yolk and single oil globule. The larval stage is extensively described, with the species having 24 myomere
Myomere
Myomere are the blocks of skeletal muscle tissue found commonly in chordates. They are commonly zig-zag, "W" or "V"-shaped muscle fibers. The myomeres are separated from adjacent myomere by connective tissues and most easily seen in larval fishes or in the olm...
s. The growth of the species is not reported, however numerous morphometric (length vs weight) studies have been carried out on the species. The population structure in Indian waters has also been well studied, with the most recent of these suggesting a major recruitment event occurs between May and August. These studies also guide fisheries regulations, with a theoretical maximum yield achieved when fish are only taken once they reach 18 cm.
Relationship to humans
The torpedo scad is of major importance to commercial fisheries in the central Indo-Pacific region (including India), and of moderate to minor importance elsewhere. Statistics recorded by the FAOFão
Fão is a town in Esposende Municipality in Portugal....
do not include India, however even without this country the annual take of torpedo scad has increased from 70 000 t
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
in 1997 to 107 000 t in 2007. On the basis of these statistics, the biggest utiliser of the species is Indonesia, with a take of 42 000 t followed by Malaysia with a take of 22 000 t. Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
and the 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...
also take large quantities of the fish, with around 18 000 t each annually. Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
ern countries also record this species in their hauls, but at lower amounts of between 50 and 5000 t. In more southerly regions such as South Africa, it is a rare catch, usually appearing in beach seines. The species is taken by a variety of netting methods such as beach seines, trawls, purse seines and other types of trap including hook and line. It is usually marketed fresh, dried or salted
Salting (food)
Salting is the preservation of food with dry edible salt. It is related to pickling . It is one of the oldest methods of preserving food, and two historically significant salt-cured foods are dried and salted cod and salt-cured meat.Salting is used because most bacteria, fungi and other potentially...
. Torpedo scad are often caught by recreational fishermen
Angling
Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...
throughout their range, however are not considered a target for gamefishing. They readily take small lures and are good sport on light tackle. Torpedo scad are said to have fair to good quality flesh
Fish (food)
Fish is a food consumed by many species, including humans. The word "fish" refers to both the animal and to the food prepared from it. Fish has been an important source of protein for humans throughout recorded history.-Terminology:...
, however are not very popular. Some chefs recommend frying or steaming the fish, although grilling is also acceptable. In polluted waters it has been demonstrated the fish contain higher than acceptable levels of heavy metals
Heavy metals
A heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
, and should be avoided in such regions. Torpedo scad are often used as live baits for larger gamefish.