Thai whiting
Encyclopedia
The Thai whiting, Sillago intermedius, is a species of coast
al marine
fish
of the smelt-whiting family
Sillaginidae
. The Thai whiting ranges from the west coast of India
to the Gulf of Thailand
in the east, inhabiting silt
y substrates
in shallow waters. First identified in 1977 from a specimen
found in a fish market
, the species has had little research performed on its biology
, and is frequently misidentified as Sillago sihama or Sillago maculata Thai whiting are commonly caught by fishermen throughout their range and are marketed fresh locally.
in the genus
Sillago
, which is one of three divisions of the smelt whiting family
Sillaginidae
. The smelt-whitings are Perciformes
in the suborder Percoidea
.
The species was first recognized and named Sillago intermedius by Wongratana in 1977 after a number of unknown sillaginid individuals were found in a Thai fish market whilst Wongratana was collecting specimens of sillaginids to be sent to McKay for his review of the Sillaginidae. He based his description on a specimen
taken from the east coast of Thailand in 1977, which was allocated to be the holotype
. The species has been subsequently misidentified as Sillago maculata, as the blotches on the species are fairly similar.
extending to the two rows of cheek
scales and head. The first dorsal fin
has 11 spines and the second dorsal fin has 1 leading spine with 21 to 22 soft rays posterior. The anal fin is similar to the second dorsal fin, but has 2 spines with 21 to 22 soft rays posterior to the spines. Other distinguishing features include 67 to 70 lateral line
scales and a total of 34 vertebrae. The species has a known maximum length of 20 cm.
The swim bladder has two anterior extensions which extend forward and diverge before terminating above the auditory capsule. Two lateral extensions commence anteriorly, sending tubules to the anterior and extending below the abdominal wall adjacent to the swimbladder. There are also two posterior extensions which project into the post-coelomic region. The morphology of the swim-bladder is quite similar to S. sihama, but the tubules are very simple, unlike S. sihama which has complexly folded extensions.
The Thai whiting is a pale silvery colour, being darker on top and lighter below. The top of the snout is blackish, while the opercle
, preopercle and preorbital
are bright silver. The sides of the body below the lateral line have a longitudinal row of 8 or 9 dark blotches. The back also has a row of dusky blotches. The caudal fin has darker upper and lower rays, with all other fins hyaline
in appearance.
where it ranges the Gulf of Thailand, extending westward to the west coast of the Indian subcontinent
, apparently having a fairly scattered distribution.
The Thai whiting is a shallow water, inshore species which inhabits open silt
y substrates at depths of 0 to 10 m, occasionally entering estuaries. Nothing else known of its biology.
, the Thai whiting is taken on a small scale by fishermen throughout its range, where it is sold fresh in local market
s. It is often not differentiated form other sillaginids due to its close resemblance to both S. sihama and S. maculata.
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
al marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
of the smelt-whiting family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Sillaginidae
Sillaginidae
The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fishes in the order Perciformes. The smelt-whitings inhabit a wide region covering much of the Indo-Pacific, from the west coast of Africa east to Japan...
. The Thai whiting ranges from the west coast of 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...
to the Gulf of Thailand
Gulf of Thailand
The Gulf of Thailand , also known in to Malays as Teluk Siam literally meant Gulf of Siam, is a shallow arm of the South China Sea.-Geography:...
in the east, inhabiting silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
y substrates
Substrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
in shallow waters. First identified in 1977 from a specimen
Specimen
A specimen is a portion/quantity of material for use in testing, examination, or study.BiologyA laboratory specimen is an individual animal, part of an animal, a plant, part of a plant, or a microorganism, used as a representative to study the properties of the whole population of that species or...
found in a fish market
Market
A market is one of many varieties of systems, institutions, procedures, social relations and infrastructures whereby parties engage in exchange. While parties may exchange goods and services by barter, most markets rely on sellers offering their goods or services in exchange for money from buyers...
, the species has had little research performed on its biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
, and is frequently misidentified as Sillago sihama or Sillago maculata Thai whiting are commonly caught by fishermen throughout their range and are marketed fresh locally.
Taxonomy and naming
The Thai whiting is one of 29 speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Sillago
Sillago
Sillago is one of three genera in the family Sillaginidae containing the smelt-whitings, and contains 29 species, making Sillago the only non-monotypic genus in the family. Distinguishing among Sillago species can be difficult, with many similar in appearance and colour, forcing the use of swim...
, which is one of three divisions of the smelt whiting family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Sillaginidae
Sillaginidae
The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fishes in the order Perciformes. The smelt-whitings inhabit a wide region covering much of the Indo-Pacific, from the west coast of Africa east to Japan...
. The smelt-whitings are Perciformes
Perciformes
The Perciformes, also called the Percomorphi or Acanthopteri, is one of the largest orders of vertebrates, containing about 40% of all bony fish. Perciformes means perch-like. They belong to the class of ray-finned fish and comprise over 7,000 species found in almost all aquatic environments...
in the suborder Percoidea
Percoidea
Percoidea is a superfamily of fish of the order Perciformes....
.
The species was first recognized and named Sillago intermedius by Wongratana in 1977 after a number of unknown sillaginid individuals were found in a Thai fish market whilst Wongratana was collecting specimens of sillaginids to be sent to McKay for his review of the Sillaginidae. He based his description on a specimen
Specimen
A specimen is a portion/quantity of material for use in testing, examination, or study.BiologyA laboratory specimen is an individual animal, part of an animal, a plant, part of a plant, or a microorganism, used as a representative to study the properties of the whole population of that species or...
taken from the east coast of Thailand in 1977, which was allocated to be the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
. The species has been subsequently misidentified as Sillago maculata, as the blotches on the species are fairly similar.
Description
As with most of the genus Sillago, the Thai whiting has a slightly compressed, elongate body tapering toward the terminal mouth. The body is covered in small ctenoid scalesScale (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...
extending to the two rows of cheek
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...
scales and head. The first 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...
has 11 spines and the second dorsal fin has 1 leading spine with 21 to 22 soft rays posterior. The anal fin is similar to the second dorsal fin, but has 2 spines with 21 to 22 soft rays posterior to the spines. Other distinguishing features include 67 to 70 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...
scales and a total of 34 vertebrae. The species has a known maximum length of 20 cm.
The swim bladder has two anterior extensions which extend forward and diverge before terminating above the auditory capsule. Two lateral extensions commence anteriorly, sending tubules to the anterior and extending below the abdominal wall adjacent to the swimbladder. There are also two posterior extensions which project into the post-coelomic region. The morphology of the swim-bladder is quite similar to S. sihama, but the tubules are very simple, unlike S. sihama which has complexly folded extensions.
The Thai whiting is a pale silvery colour, being darker on top and lighter below. The top of the snout is blackish, while the opercle
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....
, preopercle and preorbital
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
are bright silver. The sides of the body below the lateral line have a longitudinal row of 8 or 9 dark blotches. The back also has a row of dusky blotches. The caudal fin has darker upper and lower rays, with all other fins hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
in appearance.
Distribution and habitat
As its name suggests, the Thai whiting occurs predominantly in ThailandThailand
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...
where it ranges the Gulf of Thailand, extending westward to the west coast of the Indian subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...
, apparently having a fairly scattered distribution.
The Thai whiting is a shallow water, inshore species which inhabits open silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
y substrates at depths of 0 to 10 m, occasionally entering estuaries. Nothing else known of its biology.
Relationship to humans
Like other sillaginidsSillaginidae
The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fishes in the order Perciformes. The smelt-whitings inhabit a wide region covering much of the Indo-Pacific, from the west coast of Africa east to Japan...
, the Thai whiting is taken on a small scale by fishermen throughout its range, where it is sold fresh in local market
Market
A market is one of many varieties of systems, institutions, procedures, social relations and infrastructures whereby parties engage in exchange. While parties may exchange goods and services by barter, most markets rely on sellers offering their goods or services in exchange for money from buyers...
s. It is often not differentiated form other sillaginids due to its close resemblance to both S. sihama and S. maculata.