Northern whiting
Encyclopedia
The northern whiting, Sillago sihama (also known as the silver whiting and sand smelt), is a marine
fish
, the most widespread and abundant member of the smelt-whiting family Sillaginidae
. The northern whiting was the first species of sillaginid scientifically described and is therefore the type species
of both the family Sillaginidae and the genus Sillago
. The species is distributed in the Indo-Pacific
region from South Africa
in the west to Japan
and Indonesia
in the east, also becoming an invasive species to the Mediterranean through the Suez Canal. The northern whiting inhabits coastal areas to 60 m, but is most often found in shallow water around bays and estuaries, often entering freshwater. It is a carnivore, taking a variety of polychaetes and crustaceans. The species is of major economic importance
throughout the Indo-Pacific, being the most frequently taken sillaginid by seine nets and cast nets and marketed fresh.
in the genus
Sillago
, which is one of three genera in the smelt-whiting family
Sillaginidae
. The smelt-whitings are Perciformes
in the suborder Percoidea
.
The northern whiting was first described by Peter Forsskål
in 1775 under the name Atherina sihama, mistaking the fish as a species of hardyhead. The species was subsequently placed in the genus Platycephalus
, before its true identity as a new genus was realized and Sillago was created in 1816. This was the first description and naming of any smelt-whiting, even though the author initially placed the species in the wrong genus. This makes S. sihama the type species of its genus, Sillago, as well as the type species of the family Sillaginidae, which was not to be named until 1846. However, Forsskål's name was not the only one applied to the species, with three other names given to the fish after the first correct naming. Two of these, S. acuta and S. erythraea were made by Georges Cuvier
, and the other, Sciaena malabarica by Bloch
and Schneider. These later names are junior synonyms and are discarded under the ICZN
rules.
Due to its wide distribution, the species has been applied a number of common names, with northern whiting, silver whiting, sand smelt and silver sillago the most common English
names.
. The dorsal fin is in two parts, the first made of feeble spines and the second of soft rays headed by a single feeble spine, while the ventral profile is straight.
The fin
anatomy
is highly useful for identification purposes, with the species having 11 spines in the first dorsal fin
, with one spine and 20 to 23 soft rays on the second dorsal fin. The anal fin has two spines with 21 to 23 soft rays posterior to the spines. Lateral line
scale
s and cheek
scales are also distinctive, with northern whiting possessing 66 to 72 lateral line scales and cheek scales positioned in 3–4 rows, all of which are ctenoid. The amount of vertebrae are also diagnostic, having 34 in total. The swim bladder is the most accurate diagnostic feature, having two posterior extensions and two anterior extensions. The two anterior extensions extend forward and diverge to end on each side of the basioccipital above the auditory capsule. Two lateral extensions also commence anteriorly, each of them sending a blind tubule anterolaterally and then extending along the abdominal wall. The lateral extensions are normally convoluted and have blind tubules arising along their length. The two posterior tapering extensions project into the caudal region, with one usually longer than the other.
The colour of the body is variable, often being light tan, silvery yellow-brown, sandy brown, or honey coloured. The underside of the fish is usually paler, being brown to white in colour. A silver midlateral, longitudinal stripe is normally present. The dorsal fins are dusky on each end, with or without rows of dark brown spots on the second dorsal fin membranes. The caudal fin is dusky terminally, and there is no dark blotch at the base of the pectoral fin as in other sillaginids. All other fins are hyaline
, but the anal fin occasionally has a whitish margin.
to the eastern Mediterranean, passing through the Suez Canal
from the Red Sea
since 1977 as part of the Lessepsian migration, becoming widespread.
The northern whiting is primarily an inshore species, rarely seen in depth of more than 20 m. It commonly inhabits both high energy beach
es and sandbars as well as more protected bays along mangrove
creeks and tidal flats. The species commonly enters estuaries, and has even been recorded in freshwater, despite the fact it has no anatomical adaptations to cope with this change. The northern whiting does not migrate or move offshore at various times of the year like some co-occurring sillaginids.
worms, small prawn
s and copepod
s, with other Crustacea including Decopoda, Ocypoda, shrimp
s, and amphipods also taken. Small fish are often taken and filamentous algae
is consumed. Australian specimens frequently contain polychaete worms and small Crustacea. The species often has a similar, but slightly different diet compared to other coexisting sillaginids and other fishes, with few cases of wide dietary overlap recorded. The juveniles and adults also show disparity in their diets, with juveniles taking zooplankton
such as copepods, while adults take larger crustaceans and polychaetes.
at a minimum 106 mm in males an 117 mm in females, although most individuals from both sexes mature once they reach 130 mm in length and one year of age. Growth in the species is rapid, attaining a length of 13 to 14 cm at about 1 year, 16 to 20 cm at 2 years, 20 to 24 cm at 3 years and 24 to 28 cm by 4 years of age.
Spawning
occurs year round, but a peak of spawning activity occurs once during the year at variable times over the species range. Peak of spawning in Thailand
is August and November, November to April in the Philippines and November to March in India. The egg
is spherical, colourless and buoyant, 0.5 to 0.6 mm in diameter, and without a large oil globule. Fecundity varied between 16 682 and 166 130. The larval development of S. sihama has been extensively described by Kato et al., with the distinguishing feature of the larva
e being the pattern of melanophores distributed on the caudal fin base, having these in a vertical line.
takes place in June to July. The catches reported in this single country range from 102 t (1980) to 859 t (1982) with an average of 404 t. The species has come under heavy threat in Chinese waters from overfishing
and environmental pollution.
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...
, the most widespread and abundant member of the smelt-whiting family 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 northern whiting was the first species of sillaginid scientifically described and is therefore the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of both the family Sillaginidae and the genus 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...
. The species is distributed in the 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 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 Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and 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...
in the east, also becoming an invasive species to the Mediterranean through the Suez Canal. The northern whiting inhabits coastal areas to 60 m, but is most often found in shallow water around bays and estuaries, often entering freshwater. It is a carnivore, taking a variety of polychaetes and crustaceans. The species is of major economic importance
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
throughout the Indo-Pacific, being the most frequently taken sillaginid by seine nets and cast nets and marketed fresh.
Taxonomy
The northern 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 genera in 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 northern whiting was first described by Peter Forsskål
Peter Forsskål
Peter Forsskål, sometimes spelled Pehr Forsskål, Peter Forskaol, Petrus Forskål or Pehr Forsskåhl, was a Swedish explorer, orientalist, naturalist and an apostle of Carl Linnaeus.-Early life:...
in 1775 under the name Atherina sihama, mistaking the fish as a species of hardyhead. The species was subsequently placed in the genus Platycephalus
Platycephalus
Platycephalus is a genus of mostly-marine, bottom-dwelling fish in the family Platycephalidae.-Etymology and Taxonomic History:The name of the genus, Platycephalus is derived from the Greek words for "flat" and "head"...
, before its true identity as a new genus was realized and Sillago was created in 1816. This was the first description and naming of any smelt-whiting, even though the author initially placed the species in the wrong genus. This makes S. sihama the type species of its genus, Sillago, as well as the type species of the family Sillaginidae, which was not to be named until 1846. However, Forsskål's name was not the only one applied to the species, with three other names given to the fish after the first correct naming. Two of these, S. acuta and S. erythraea were made by Georges Cuvier
Georges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
, and the other, Sciaena malabarica by 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 :...
and Schneider. These later names are junior synonyms and are discarded under the ICZN
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
rules.
Due to its wide distribution, the species has been applied a number of common names, with northern whiting, silver whiting, sand smelt and silver sillago the most common English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
names.
Description
The northern whiting's similarity to all other species in the genus Sillago has led to many less abundant species being confused with it. The species is known to grow to a maximum size of 31 cm, however reports dating back to 1850 in Bengal suggest the species attains 3 feet (91 cm), which would make it the largest species of sillaginid. These reports were never etched into the literature on the species, possibly because of presumed confusion with the similar but unrelated and larger milkfish and bonefish that inhabit the area. The species has a slightly compressed, elongate body tapering toward the terminal mouthMouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
. The dorsal fin is in two parts, the first made of feeble spines and the second of soft rays headed by a single feeble spine, while the ventral profile is straight.
The fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
is highly useful for identification purposes, with the species having 11 spines in 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...
, with one spine and 20 to 23 soft rays on the second dorsal fin. The anal fin has two spines with 21 to 23 soft rays posterior to the spines. 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...
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 and 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 are also distinctive, with northern whiting possessing 66 to 72 lateral line scales and cheek scales positioned in 3–4 rows, all of which are ctenoid. The amount of vertebrae are also diagnostic, having 34 in total. The swim bladder is the most accurate diagnostic feature, having two posterior extensions and two anterior extensions. The two anterior extensions extend forward and diverge to end on each side of the basioccipital above the auditory capsule. Two lateral extensions also commence anteriorly, each of them sending a blind tubule anterolaterally and then extending along the abdominal wall. The lateral extensions are normally convoluted and have blind tubules arising along their length. The two posterior tapering extensions project into the caudal region, with one usually longer than the other.
The colour of the body is variable, often being light tan, silvery yellow-brown, sandy brown, or honey coloured. The underside of the fish is usually paler, being brown to white in colour. A silver midlateral, longitudinal stripe is normally present. The dorsal fins are dusky on each end, with or without rows of dark brown spots on the second dorsal fin membranes. The caudal fin is dusky terminally, and there is no dark blotch at the base of the pectoral fin as in other sillaginids. All other fins are 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...
, but the anal fin occasionally has a whitish margin.
Distribution and habitat
The northern whiting is the most geographically widespread of the Sillaginidae, but is still confined to the Indian and Western Pacific Oceans. Its easternmost range is from South Africa north along the west coast of Africa and into the Red sea and Persian Gulf. It is common along the Indian and Asian coast, extending to Taiwan and has been recorded in Japan, however these likely are confused with S. japonica. It is common throughout the Indonesian Archipelago, the Philippines and extends as far south as northern Australia. The species has been declared an invasive speciesInvasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
to the eastern Mediterranean, passing through the Suez Canal
Suez Canal
The Suez Canal , also known by the nickname "The Highway to India", is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869 after 10 years of construction work, it allows water transportation between Europe and Asia without navigation...
from the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
since 1977 as part of the Lessepsian migration, becoming widespread.
The northern whiting is primarily an inshore species, rarely seen in depth of more than 20 m. It commonly inhabits both high energy beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
es and sandbars as well as more protected bays along mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...
creeks and tidal flats. The species commonly enters estuaries, and has even been recorded in freshwater, despite the fact it has no anatomical adaptations to cope with this change. The northern whiting does not migrate or move offshore at various times of the year like some co-occurring sillaginids.
Biology
Like most members of the family, S. sihama can bury itself in the sand when danger approaches and commonly avoids seine-nets by employing this behaviour, giving them the common name 'sandborer' in some countries.Diet
The principal items of diet are polychaetePolychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
worms, small 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 and copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s, with other Crustacea including Decopoda, Ocypoda, 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, and amphipods also taken. Small fish are often taken and filamentous algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
is consumed. Australian specimens frequently contain polychaete worms and small Crustacea. The species often has a similar, but slightly different diet compared to other coexisting sillaginids and other fishes, with few cases of wide dietary overlap recorded. The juveniles and adults also show disparity in their diets, with juveniles taking zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
such as copepods, while adults take larger crustaceans and polychaetes.
Reproduction
Northern whiting reach sexual maturitySexual 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 a minimum 106 mm in males an 117 mm in females, although most individuals from both sexes mature once they reach 130 mm in length and one year of age. Growth in the species is rapid, attaining a length of 13 to 14 cm at about 1 year, 16 to 20 cm at 2 years, 20 to 24 cm at 3 years and 24 to 28 cm by 4 years of age.
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...
occurs year round, but a peak of spawning activity occurs once during the year at variable times over the species range. Peak of spawning in 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...
is August and November, November to April in the Philippines and November to March in India. The egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
is spherical, colourless and buoyant, 0.5 to 0.6 mm in diameter, and without a large oil globule. Fecundity varied between 16 682 and 166 130. The larval development of S. sihama has been extensively described by Kato et al., with the distinguishing feature of the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e being the pattern of melanophores distributed on the caudal fin base, having these in a vertical line.
Relationship to humans
Considerable catches of northern whiting are made but generally not reflected in the fishery statistics of countries they are taken in. In Pakistan the main fisheryFishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
takes place in June to July. The catches reported in this single country range from 102 t (1980) to 859 t (1982) with an average of 404 t. The species has come under heavy threat in Chinese waters from overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
and environmental pollution.