Sillaginidae
Encyclopedia
The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family
of benthic coastal marine
fish
es 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
and south to Australia
. The family comprises only three genera
and thirty one species
, of which a number are dubious, with the last major revision of the family in 1992 unable to confirm the validity of a number of species. They are elongate, slightly compressed fish often light brown to silver in colour with a variety of markings and patterns on their upper body. The Sillaginidae are not related to a number of fishes commonly called 'whiting' in the Northern Hemisphere
, including the fish originally called whiting, Merlangius merlangus
.
The smelt-whitings are mostly inshore fishes that inhabit sandy, silty and muddy substrates
on both low and high energy environments ranging from protected tidal flats and estuaries to surf zone
s. A few species predominantly live offshore on deep sand shoal
s and reef
s, although the larvae and juvenile phases of most species return to inshore grounds, where they spend the first few years of their lives. Smelt-whitings are benthic carnivores that prey predominantly on polychaete
s, a variety of crustacean
s, molluscs and to a lesser extent echinoderm
s and fish, feeding by detecting vibrations emitted by their prey.
The family is highly important to fisheries throughout the Indo-Pacific, with species such as the Northern whiting
, Japanese whiting
and King George whiting
forming the basis of major fisheries throughout their range. Many species are also of major importance to small subsistence fisheries while others are little more than occasional bycatch
. Smelt-whitings are caught by a number of methods including trawling
, seine nets and cast nets. In Australia and Japan in particular, members of the family are often highly sought by recreational fishermen
who also seek the fish for their prized flesh.
The first species of sillaginid to be scientifically described was Sillago sihama, by Peter Forsskål
in 1775, who initially referred the species to a genus of hardyhead, Atherina
. It was not until 1817 that the type genus Sillago was created by Georges Cuvier
based on his newly described species Sillago acuta, which was later found to be a junior synonym of S. sihama and subsequently discarded. Cuvier continued to describe species of sillaginid with the publishing of his ichthyological
work Histoire Naturelle des Poissons
with Achille Valenciennes
in 1829, also erecting the genus Sillaginodes in this work. The species Cheilodipterus panijus was named in 1822 by Francis Buchanan-Hamilton and was subsequently reexamined by Theodore Gill
in 1861, leading to the creation of the monotypic
genus Sillaginopsis. John Richardson
was the first to propose that Sillago, the only genus of sillaginid then recognised, be assigned to their own taxonomic family, "Sillaginidae" (used interchangeably with 'Sillaginoidae'), at a meeting of the British Association for the Advancement of Science
. There were, however, many differing opinions on the relationships of the "sillaginoids", leading to the naturalists of the day continually revising the position of the three genera, placing in them in a number of families. The first review of the sillaginid fishes was Gill's 1861 work "Synopsis of the sillaginoids", in which the name "Sillaginidae" was popularized and expanded on to include Sillaginodes and Sillaginopsis, however the debate on the placement of the family remained controversial.
In the years after Gill's paper was published, over thirty 'new' species of sillaginid were reported and scientifically described, many of which were synonym
s of previously described species, with similarity between species as well as minor geographical variation
confounding taxonomists. It wasn't until 1985 when Roland McKay of the Queensland Museum
published a comprehensive review of the family that these relationships were formally resolved, although a number of species are still listed as doubtful, with McKay unable to locate the holotypes. Along with the review of previously described species, McKay described an additional seven species, a number of which he described as subspecies
. After this 1985 paper, additional specimen
s came to light, proving that all the subspecies he had identified were individual species. In 1992 McKay published a synopsis of the Sillaginidae for the FAO
, in which he elevated these subspecies to full species status.
The name "Sillaginidae" was derived from Cuvier's Sillago, which itself takes its name from a locality in Australia, possibly Sillago reef
off the coast of Queensland. The term Sillago is derived from the Greek term "syllego", which means "to meet".
due to the loss of the holotype
specimen. This classification follows Fishbase
, which itself is based on McKay's last revision of the family.
marking the first appearance of the family. The family is thought to have evolved
in the Tethys Sea of central Australia, before colonizing southern Australia during the upper Eocene after a seaway broke through south of Tasmania. During the Oligocene, the family spread to the north and south, occupying a much more extensive range than their current Indo-Pacific distribution. Fossils suggest the sillaginids ranged as far north as Poland
and Germany
, and as far south as New Zealand
, found in shallow water sedimentary deposits along with other species of extant genera.
There have been at least eight fossil
sillaginid species found, all of which are believed to be of the genus Sillago based on the only remains found; otolith
s. Only one species of extant sillaginid, Sillago maculata, has been found in the fossil record, and this was in very recent Pleistocene
sediment
s.
Phylogeny of the Sillaginidae, illustrating the three subgenra of Sillago proposed by McKay.
The relationships of the Sillaginidae are poorly known, with very similar morphological
characteristics and a lack of genetic
studies restricting the ability to perform cladistic analyses on the family. Being the fossil sillaginids are based on the comparison of fossil otoliths, with no other type of remains found thus far, this also prevents the reconstruction of the evolution of the family through fossil species. While the position of the Sillaginidae in the order Perciformes is firmly established due to a number of synapomorphies shared with other members of the order, no sister group has been established for the family. The current taxonomic status of the family is thought to represent a basic picture of the group's phylogeny, with McKay further dividing the genus Sillago into three subgenera based on shared morphological characters of the swimbladder. The genera Sillaginodes and Sillaginopsis have the most plesiomorphic characteristics; being monotypic, and distinct from Sillago. Sillago is further divided into three subgenera based primarily on swim bladder morphology; Sillago, Parasillago and Sillaginopodys, which also represent evolutionary relationships. Whilst genetic studies have not been done on the family, they have been used to establish the relationship of what were thought to be various subspecies of school whiting, S. bassensis and S. flindersi. Furthermore, morphological data suggests a number of Australian species diverged very recently during the last glacial maximum
, which caused land bridge
s to isolate population
s of fish. The two aforementioned species of school whiting, S. maculata and S. burrus, and S. ciliata and S. analis are all thought to be products of such a process, although only the school whiting have anything other than similar morphology as evidence of this process.
. The body shape and fin placement of the family is quite similar to most of the members of the order Perciformes. Their bodies are elongate, slightly compressed, with a head that tapers toward a terminal mouth
. The mouth has a band of brush-like teeth with canine teeth
present only in the upper jaw
of Sillaginopsis. The cranial sensory system
of the family is well developed above and laterally, with the lower jaw having a pair of small pores behind which is a median pit containing a pore on each side. On each side of the elongate head the operculum
has a short sharp spine. They have two true dorsal fin
s; the anterior one supported by 10 to 13 spines while the long rear one is held up by a single leading spine followed by 16 to 27 soft rays. The anal fin is similar to the second dorsal fin, having two small slender spines followed by 14 to 26 soft rays. Their bodies are covered in ctenoid scales
, with the exception of the cheek
which may have cycloid or ctenoid scales. There is a wide variation in the amount of lateral line scales, ranging from 50 to 141. The swimbladder in the Sillaginidae is either absent, poorly developed, or highly complex with anterior and lateral extensions that project well into the caudal region. A unique duct
-like process is present from the ventral surface of the swimbladder to just before the urogenital opening
in most species. The presence and morphology of each species' swim bladder is often their major diagnostic feature, with McKay's three proposed subgenera based on swimbladder morphology alone. The sillaginids have only a small range of body colourings and frequently the only colour characteristics to identify between species are the arrangements of spots and bars on their upper bodies. Most of the family are a pale brown – creamy white colour, while a few species are silver all over. The undersides of the fish are usually lighter than the upper side, and the fins range from yellow to transparent
, often marked by bars and spots.
The Sillaginidae are distributed throughout the Indo-Pacific region, ranging from the west coast of Africa to Japan and Taiwan
in the east, as well occupying as a number of small islands including New Caledonia
in the Pacific Ocean
. While they have a fairly wide distribution, the highest species densities occur along the coasts of India
, China
, Taiwan, South East Asia, the Indonesian Archipelago and northern Australia
. One species of sillaginid, Sillago sihama, has been declared an invasive species
to the Mediterranean, passing through the Suez Canal
from the Red Sea
since 1977 as part of the Lessepsian migration, becoming widespread.
Sillaginids are primarily inshore marine fishes inhabiting stretches of coastal waters, although a few species move offshore in their adult stages to deep sand banks or reefs to a maximum known depth of 180 m. All species primarily occupy sand
y, silt
y or mud
dy substrates, often using seagrass
or reef as cover. They commonly inhabit tidal flats, beach
zones, broken bottoms and large areas of uniform substrate. Although the family is marine, many species inhabit estuarine environments, with some such as Sillaginopsis panijus also found in the upper reaches of the estuary. Each species often occupies a specific niche
to avoid competition
with co-occurring sillaginids, often inhabiting a specific substrate type, depth, or making use of surf zones and estuaries. The juveniles often show distinct changes in habitat
preference as they mature, often moving to deeper waters. No members of the family are known to undergo migratory movements, and have been shown to be relatively weak swimmers, relying on currents to disperse juveniles.
s, with all of the species whose diet
s have been studied showing similar prey preferences. Studies from the waters of Thailand
, Philippines
and Australia have shown that polychaetes, a variety of crustaceans, molluscs and to a lesser extent echinoderms and fish are the predominant prey items of the family. Commonly taken crustaceans include decapods
, copepod
s and isopods, while the predominant molluscs taken are various species of bivalves, especially the unprotected siphon filters that protrude from the shells. In all species studied, some form of diet shift occurs as the fishes mature, often associated with a movement to deeper waters and thus to new potential prey. The juveniles often prey on planktonic prey, with small copepods, isopods and other small crustaceans often taken. Whilst many species have a change in niche to reduce intraspecific competition
, there are often many species of sillaginid inhabiting a geographical area. Where this occurs, there is often definite diet differences between species, often associated with a niche specialization. The sillaginid's distinctive body shape and mouth placement is an adaptation to bottom feeding, which is the predominant method of feeding for all whiting species. All larger whiting feed by using their protrusile jaws and tube-like mouths to suck up various types of prey from in, on or above the ocean substrate, as well as using their nose as a 'plough
' to dig through the substrate.
There is a large body of evidence that shows whiting do not rely on visual cues when feeding, instead using a system based on the vibrations emitted by their prey.
of most systems, and frequently fall prey to a variety of aquatic
and aerial predators. Their main aquatic predators are a wide variety of larger fish, including both teleosts and a variety of shark
s and ray
s. Marine mammal
s including seals
and dolphin
s have been reported to have taken sillaginids as a main food source. Seabird
s are also another major predator of the family, with diving species such as Cormorant
s taking older fish in deeper waters while juvenile fish in shallow water fall prey to wading birds. Sillaginids are often called 'sandborers' due to their habit of burying themselves in the substrate to avoid predators, much in the same way as they forage, by ploughing their nose into the substrate. This defense is even used against human
fishermen, who frequently wade barefoot to feel for buried fish. The Sillaginidae are also host to a variety of well studied internal and external parasites, which are represented prominently by the groups Digenea
, Monogenea
and Myxosporea
, Copepoda and Nematoda.
at a slightly different age, with each sex often showing a disparity in time of maturation. Each species also spawns over a different season and the spawning season often differs within a species, usually as a function of latitude
; a feature not unique to sillaginids. The proximity to shore of spawning is also different between species, as each species usually does not migrate
inshore to spawn, even if the juvenile
s require shallow water for protection, instead relying on currents. The fecundity of sillaginids is variable, with a normal range between 50 000 – 100 000. The eggs
are small (0.6 to 0.8 mm), spherical and pelagic, hatching around 20 days after fertilisation
. The larva
e are quite similar, requiring a trained developmental biologist to identify between species. The larvae and juveniles are at the mercy of the ocean current
s, being too weaker swimmers to actively seek out coastlines. Currents are thought to have been responsible for the distribution of mainland
species to offshore island
s as well as the current widespread distribution of Sillago sihama. In all studied species, juveniles inhabit shallow waters in protected embayments, estuaries, tidal creek
s and lagoon
s as well as exposed surf zones, usually over tidal flats and seagrass beds. As the fish mature, they generally move to deeper waters, showing a change in diet.
in the Indo-Pacific region, with a few species making up the bulk of whiting catches. Their high numbers, coupled with their highly regarded flesh
are the reason for this, and their inshore nature also has made them popular targets for recreational fishermen
in a number of countries. With overfishing
rife in some areas, sustainable aquaculture
has allowed the commercial farming of a number of sillaginid species, as well as the use of farmed fish to restock depleted estuaries. At least one species, the Gangetic whiting, has occasionally been used in brackish water
aquaria.
A small number of sillaginids have large enough populations to allow an entire fishery to be based around them, with King George whiting, northern whiting, Japanese whiting, sand whiting and school whiting the major species. There have been no reliable estimates of catches for the entire family, as catch statistics
generally include only those species taken in large numbers, but there are some species which make up significant numbers of the bycatch. To add to this problem, many of the lesser known species are taken by subsistence fisheries and not reported. From estimates by the FAO
, however, it is evident that the family is one of the most important in the Indo-Pacific region, having an estimated catch of 22 718 tonne
s in 1990 alone. In this same report, it was shown that the greatest three utilizers of sillaginids were the Philippines, Western Australia and Thailand respectively. The records also suggested that the catch increased from 1983 when it was 17 570 t, up to the last estimate in 1990 of 22 718 t. No such estimates have been carried out since. Modern records for Australia show that this trend has reversed, with all catches from Australia totaling 4 372 t in 2006 compared with 1990's 6000 t haul. Statistics from other countries are unavailable for such comparison.
Sillaginids are taken by a variety of fishing methods, with inshore catches predominantly taken using beach seine nets and cast nets. Due to the alert nature of sillaginids, skill is required on creeping up quietly enough to be able to net fish with a cast net, with experienced fishers often paddling into the sun toward a school and drifting slowly upon it before casting the net. In deeper waters, commercial trawlers and longliners take the most fish, with a number of sillaginids taken in prawn trawls as bycatch. The fish are normally marketed fresh locally under various names, with "Ashuos" commonly used in many countries for various sillaginids. At least one export fishery exists in Australia whereby S. flindersi is exported to Thailand where the fish are repackaged and sent to Japan frozen.
common habitats from where many whiting species are caught without need for a boat. Tidal
movements also affect catches, as do lunar phases, causing whiting to 'bite' when the tide is changing. Tackle used is kept light to avoid spooking the fish, and often requires only a simple setup, with a hook
and light sinker
tied directly to the mainline usually effective. In deeper water fished from boats or where currents are strong, more complex rigs are used, often with hooks tied to dropper loops on the trace. in Australia, some specialist whiting fishermen who target the fish in the surf or on shallow banks use red bead
s or tubing to attract the fish, claiming the method produces more fish. The bait used is normally anything from the surrounding environment which the whiting naturally prey on, with polychaetes, bivalves, crustaceans such as prawns and crabs, cephalopods and small fish effective for most species. As with most species, live bait is known to produce better catches. Lure fishing for whiting is not normally practiced, but saltwater flies
have been used to good effect, as have small soft plastic lures. In some areas, restrictions to the amount and size of fish are in place and enforced by fishery authorities.
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...
of benthic coastal 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...
es in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
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...
. The smelt-whitings inhabit a wide region covering much of 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...
, from the west coast of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
east 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 south to 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...
. The family comprises only three genera
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...
and thirty one species
Species
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...
, of which a number are dubious, with the last major revision of the family in 1992 unable to confirm the validity of a number of species. They are elongate, slightly compressed fish often light brown to silver in colour with a variety of markings and patterns on their upper body. The Sillaginidae are not related to a number of fishes commonly called 'whiting' in the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
, including the fish originally called whiting, Merlangius merlangus
Merlangius merlangus
Merlangius merlangus, commonly known as whiting is an important food fish in the eastern North Atlantic, northern Mediterranean, western Baltic, and Black Sea...
.
The smelt-whitings are mostly inshore fishes that inhabit sandy, silty and muddy 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....
on both low and high energy environments ranging from protected tidal flats and estuaries to surf zone
Surf zone
As ocean surface waves come closer to shore they break, forming the foamy, bubbly surface we call surf. The region of breaking waves defines the surf zone. After breaking in the surf zone, the waves continue to move in, and they run up onto the sloping front of the beach, forming an uprush of...
s. A few species predominantly live offshore on deep sand shoal
Shoal
Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...
s and reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s, although the larvae and juvenile phases of most species return to inshore grounds, where they spend the first few years of their lives. Smelt-whitings are benthic carnivores that prey predominantly on polychaete
Polychaete
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...
s, a variety of 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, molluscs and to a lesser extent echinoderm
Echinoderm
Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....
s and fish, feeding by detecting vibrations emitted by their prey.
The family is highly important to fisheries throughout the Indo-Pacific, with species such as the Northern whiting
Northern whiting
The northern whiting, Sillago sihama , 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...
, Japanese whiting
Japanese whiting
The Japanese whiting, Sillago japonica, is a common species of coastal marine fish belonging to the smelt-whiting family, Sillaginidae...
and King George whiting
King George whiting
The King George whiting, Sillaginodes punctatus , is a coastal marine fish of the smelt-whitings family Sillaginidae. The King George whiting is endemic to Australia, inhabiting the south coast of the country from Jurien Bay, Western Australia to Botany Bay, New South Wales in the east...
forming the basis of major fisheries throughout their range. Many species are also of major importance to small subsistence fisheries while others are little more than occasional bycatch
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
. Smelt-whitings are caught by a number of methods including trawling
Trawling
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net that is used for trawling is called a trawl....
, seine nets and cast nets. In Australia and Japan in particular, members of the family are often highly sought 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...
who also seek the fish for their prized flesh.
Taxonomy
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, who initially referred the species to a genus of hardyhead, Atherina
Atherina
Atherina, is a genus of fish of Old World silverside family , found in the temporary and tropic zones. Up to 15 cm long. Widespread in the Mediterranean, Black Sea, and Sea of Azov, in lagoons and estuaries...
. It was not until 1817 that the type genus Sillago was created 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...
based on his newly described species Sillago acuta, which was later found to be a junior synonym of S. sihama and subsequently discarded. Cuvier continued to describe species of sillaginid with the publishing of his ichthyological
Ichthyology
Ichthyology is the branch of zoology devoted to the study of fish. This includes skeletal fish , cartilaginous fish , and jawless fish...
work Histoire Naturelle des Poissons
Histoire Naturelle des Poissons
Histoire Naturelle des Poissons was a 22-volume study of Ichthyology written by Georges Cuvier and his student Achille Valenciennes in the 1830s....
with Achille Valenciennes
Achille Valenciennes
Achille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
in 1829, also erecting the genus Sillaginodes in this work. The species Cheilodipterus panijus was named in 1822 by Francis Buchanan-Hamilton and was subsequently reexamined by Theodore Gill
Theodore Gill
Theodore Nicholas Gill was an American ichthyologist, mammalogist, malacologist and librarian.Born and educated in New York City under private tutors, Gill early showed interest in natural history. He was associated with J...
in 1861, leading to the creation of the monotypic
Monotypic
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 Sillaginopsis. John Richardson
John Richardson (naturalist)
Sir John Richardson was a Scottish naval surgeon, naturalist and arctic explorer.Richardson was born at Dumfries. He studied medicine at Edinburgh University, and became a surgeon in the navy in 1807. He traveled with John Franklin in search of the Northwest Passage on the Coppermine Expedition of...
was the first to propose that Sillago, the only genus of sillaginid then recognised, be assigned to their own taxonomic family, "Sillaginidae" (used interchangeably with 'Sillaginoidae'), at a meeting of the British Association for the Advancement of Science
British Association for the Advancement of Science
frame|right|"The BA" logoThe British Association for the Advancement of Science or the British Science Association, formerly known as the BA, is a learned society with the object of promoting science, directing general attention to scientific matters, and facilitating interaction between...
. There were, however, many differing opinions on the relationships of the "sillaginoids", leading to the naturalists of the day continually revising the position of the three genera, placing in them in a number of families. The first review of the sillaginid fishes was Gill's 1861 work "Synopsis of the sillaginoids", in which the name "Sillaginidae" was popularized and expanded on to include Sillaginodes and Sillaginopsis, however the debate on the placement of the family remained controversial.
In the years after Gill's paper was published, over thirty 'new' species of sillaginid were reported and scientifically described, many of which were synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
s of previously described species, with similarity between species as well as minor geographical variation
Genetic diversity
Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary....
confounding taxonomists. It wasn't until 1985 when Roland McKay of the Queensland Museum
Queensland Museum
The Queensland Museum is the state museum of Queensland. The museum currently operates four separate campuses; at South Brisbane, Ipswich, Toowoomba and Townsville.The museum is funded by the State Government of Queensland.-History:...
published a comprehensive review of the family that these relationships were formally resolved, although a number of species are still listed as doubtful, with McKay unable to locate the holotypes. Along with the review of previously described species, McKay described an additional seven species, a number of which he described as subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
. After this 1985 paper, additional 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...
s came to light, proving that all the subspecies he had identified were individual species. In 1992 McKay published a synopsis of the Sillaginidae for the FAO
Fão
Fão is a town in Esposende Municipality in Portugal....
, in which he elevated these subspecies to full species status.
The name "Sillaginidae" was derived from Cuvier's Sillago, which itself takes its name from a locality in Australia, possibly Sillago reef
Whitsunday Islands
The Whitsunday Islands are a collection of continental islands of various sizes off the central coast of Queensland, Australia, situated between just south of Bowen and to the north of Mackay, some north of Brisbane. The island group is centred on Whitsunday Island, while the group's commercial...
off the coast of Queensland. The term Sillago is derived from the Greek term "syllego", which means "to meet".
Classification
The following is a comprehensive list of the 31 known extant species of sillaginids, with a number of the species still in doubtNomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
due to the loss of 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...
specimen. This classification follows Fishbase
FishBase
FishBase is a comprehensive database of information about fish species . It is the largest and most extensively accessed online database on adult finfish on the web...
, which itself is based on McKay's last revision of the family.
- Family SILLAGINIDAE
- Genus Sillaginodes
- King George whitingKing George whitingThe King George whiting, Sillaginodes punctatus , is a coastal marine fish of the smelt-whitings family Sillaginidae. The King George whiting is endemic to Australia, inhabiting the south coast of the country from Jurien Bay, Western Australia to Botany Bay, New South Wales in the east...
, Sillaginodes punctatus (CuvierGeorges CuvierGeorges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
, 1829).
- King George whiting
- Genus Sillaginopsis
- Gangetic whitingGangetic whitingThe Gangetic whiting, Sillaginopsis panijus , is a species of inshore marine and estuarine fish of the smelt-whiting family, Sillaginidae. It is the most distinctive Asian member of the family due to its flattened head and trailing dorsal fins...
, Sillaginopsis panijus (HamiltonFrancis Buchanan-HamiltonDr Francis Buchanan, later known as Francis Hamilton but often referred to as Francis Buchanan-Hamilton was a Scottish physician who made significant contributions as a geographer, zoologist, and botanist while living in India.The standard botanical author abbreviation Buch.-Ham. is applied to...
, 1822).
- Gangetic whiting
- Genus SillagoSillagoSillago 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...
- Oriental trumpeter whitingOriental trumpeter whitingThe oriental trumpeter whiting, Sillago aeolus, is a widely distributed species of benthic inshore fish in the smelt-whiting family. The species ranges from east Africa to Japan, inhabiting much if the southern Asian and Indonesian coastlines. Its morphology is very similar to other species within...
, Sillago aeolus (JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& EvermannBarton Warren EvermannBarton Warren Evermann was an American ichthyologist. He was born in Monroe County, Iowa, and graduated from Indiana University in 1886. For 10 years, he served as teacher and superintendent of schools in Indiana and California. He was professor of biology at the Indiana State University in...
, 1902) - Golden lined whitingGolden lined whitingThe golden lined whiting, Sillago analis , is a species of inshore marine fish of the smelt whiting family, Sillaginidae that inhabits the coastlines of northern Australia and lower Papua New Guinea...
, Sillago analis (WhitleyGilbert Percy WhitleyGilbert Percy Whitley was a British-born Australian ichthyologist and malacologist who was Curator of Fishes at the Australian Museum in Sydney for about 40 years. He was born at Swaythling, Southampton, England, and was educated at King Edward VI School, Southampton and Osborne House...
, 1943) - Shortnose whitingShortnose whitingThe shortnose whiting, Sillago arabica, is a recently described and poorly known species of inshore marine fish of the smelt whiting family Sillaginidae that inhabits only the Persian Gulf. S. arabica is similar in morphology to other sillaginids, although has a distinctive shortened snout which...
, Sillago arabica (McKay & McCarthy, 1989) - Silver-banded whitingSilver-banded whitingThe silver-banded whiting, Sillago argentifasciata, is a narrowly distributed species of inshore marine fish of the smelt whiting family Sillaginidae that inhabits the coastline of a single province within the Philippines. The species' taxonomic status is still marginally uncertain, with the last...
, Sillago argentifasciata (Martin & Montalban, 1935) - Asian whitingAsian whitingThe Asian whiting, Sillago asiatica, is a species inshore marine fish in the smelt whiting family, Sillaginidae, distributed along the Asian coastline from the Gulf of Thailand to Taiwan. The Asian whiting's appearance is very similar to other closely related species in the genus Sillago, with swim...
, Sillago asiatica (McKay, 1982) - Slender whitingSlender whitingThe Slender whiting, Sillago attenuata, is a poorly known species of inshore marine fish of the smelt whiting family, Sillaginidae that has a distribution limited to the Persian Gulf only. The Slender whiting, like most sillaginids requires careful study to determine its identity, with ray and...
, Sillago attenuata (McKay, 1985) - Southern school whitingSouthern school whitingThe southern school whiting, Sillago bassensis, is a common species of coastal marine fish of the smelt-whiting family that inhabits the south and south-west coasts of Australia...
, Sillago bassensis (Cuvier, 1829) - Boutan's whitingBoutan's whitingBoutan's whiting, Sillago boutani, is a poorly understood species of coastal marine fish of the smelt-whiting family Sillaginidae that inhabits the waters of the Gulf of Tonkin and south eastern China...
, Sillago boutani (PellegrinJacques PellegrinJacques Pellegrin was a French zoologist.Pellegrin was born in Paris, and studied natural history. In 1894 he became assistant chairman of zoology at the Muséum national d'histoire naturelle, replacing Léon Vaillant .He got his doctorates in medicine and science...
, 1905) - Western trumpeter whitingWestern trumpeter whitingThe western trumpeter whiting, Sillago burrus, is a species of marine fish of the smelt whiting family Sillaginidae that is commonly found along the northern coast of Australia and in southern Indonesia and New Guinea...
, Sillago burrus (Richardson, 1842) - Club-foot whitingClub-foot whitingThe club-foot whiting, Sillago chondropus, is a coastal marine fish of the smelt whiting family Sillaginidae that inhabits a wide range including west Africa, India and the northern Indonesian Archipelago...
, Sillago chondropus (Bleeker, 1849) - Sand whitingSand whitingThe sand whiting, Sillago ciliata, is a common species of coastal marine fish of the family Sillaginidae, the smelt-whitings...
, Sillago ciliata (Cuvier, 1829) - Eastern school whitingEastern school whitingThe eastern school whiting, Sillago flindersi , is a species of benthic marine fish of the smelt-whiting family Sillaginidae...
, Sillago flindersi (McKay, 1985) - Indian whitingIndian whitingThe Indian whiting, Sillago indica, is a poorly known species of coastal marine fish of the smelt-whiting family Sillaginidae. The species was named in 1985, having previously being misidentified as another species of Sillago, S. parvisquamis. The Indian whiting inhabits the east and west coasts of...
, Sillago indica (McKay, Dutt & Sujatha, 1985) - Bay whitingBay whitingThe bay whiting, Sillago ingenuua, is a species of coastal marine fish of the smelt-whiting family Sillaginidae. The bay whiting's range extends throughout the west Indian Ocean, including northern Australia, Thailand, India and Taiwan, where it inhabits protected waters...
, Sillago ingenuua (McKay, 1985) - Thai whitingThai whitingThe Thai whiting, Sillago intermedius, is a species of coastal 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 silty substrates in shallow waters...
, Sillago intermedius (Wongratana, 1977) - Japanese whitingJapanese whitingThe Japanese whiting, Sillago japonica, is a common species of coastal marine fish belonging to the smelt-whiting family, Sillaginidae...
, Sillago japonica (Temminck & Schlegel, 1843) - Mud whitingMud whitingThe mud whiting, Sillago lutea, is a species of coastal marine fish in the smelt-whiting family Sillaginidae. The mud whiting was first described in 1985 and is currently known from the north west coast of Australia and the Indian coast....
, Sillago lutea (McKay, 1985) - Large-scale whitingLarge-scale whitingThe large-scale whiting, Sillago macrolepis, is a poorly understood species of coastal marine fish of the smelt- whiting family Sillaginidae. First described in 1859, the large-scale whiting is known to inhabit shallow waters along the coasts of a number of Indo-Pacific countries including Japan,...
, Sillago macrolepis (Bleeker, 1859) - Trumpeter whitingTrumpeter whitingThe trumpeter whiting, Sillago maculata, is a common species of coastal marine fish of the smelt-whiting family, Sillaginidae. The trumpeter whiting is endemic to Australia, inhabiting the eastern seaboard from southern New South Wales to northern Queensland...
, Sillago maculata (Quoy and Gaimard, 1824) - Large-headed whitingLarge-headed whitingThe large-headed whiting, Sillago megacephalus, is a dubious species of coastal marine fish in the smelt-whiting family that has only been recorded from one specimen captured off the coast of China in 1933...
, Sillago megacephalus (Lin, 1933) - Small-eyed whitingSmall-eyed whitingThe small-eyed whiting, Sillago microps, is a poorly known species of coastal marine fish of the smelt-whiting family Sillaginidae. The species is known from only two specimens; the holotype collected by Roland McKay in 1985 from a Taipei market, both specimens of which were taken from the waters...
, Sillago microps (McKay, 1985) - Rough whitingRough whitingThe rough whiting, Sillago nierstraszi, is a dubious species of coastal marine fish in the smelt-whiting family Sillaginidae. The species is known only from the holotype which was collected in 1941 on the south coast of Papua New Guinea, but is thought to be lost. S...
, Sillago nierstraszi (Hardenberg, 1941) - Small-scale whitingSmall-scale whitingThe small-scale whiting, Sillago parvisquamis , is a species of inshore marine fish of the smelt-whiting family Sillaginidae. The small-scale whiting is very similar in body shape and colour to other species in the genus Sillago, but is distinguished by having 12 or 13 spines in the first dorsal...
, Sillago parvisquamis (Gill, 1861) - Stout whitingStout whitingThe stout whiting, Sillago robusta , is a species of benthic marine fish in the smelt-whiting family Sillaginidae. Like other sillaginids, it is an elongate, slightly compressed fish, growing to a maximum known length of 30 cm...
, Sillago robusta (Stead, 1908) - Yellowfin whitingYellowfin whitingThe yellowfin whiting, Sillago schomburgkii, is a species of inshore marine fish in the smelt-whiting family Sillaginidae...
, Sillago schomburgkii (Peters, 1864) - Northern whitingNorthern whitingThe northern whiting, Sillago sihama , 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...
, Sillago sihama (Forsskål, 1775) - Soringa whitingSoringa whitingThe Soringa whiting, Sillago soringa , is a poorly known species of coastal marine fish of the smelt-whiting family, Sillaginidae. The Soringa whiting is known exclusively from the east coast of India, inhabiting shallow inshore environments, particularly sandy substrates. S...
, Sillago soringa (Dutt and Sujatha, 1982) - Estuarine whitingEstuarine whitingThe estuarine whiting, Sillago vincenti , is a species of benthic inshore marine fish of the smelt-whiting family, Sillaginidae. The estuarine whiting is very similar in appearance to the northern whiting, Sillago sihama, and as such was mistaken for the latter until 1980, when R.J...
, Sillago vincenti (McKay, 1980) - Western school whitingWestern school whitingThe western school whiting, Sillago vittata , is a species of benthic marine fish in the smelt-whiting family Sillaginidae. The species is one of three 'school whiting' that inhabit southern Australia and share a very similar appearance...
, Sillago vittata (McKay, 1985)
- Oriental trumpeter whiting
- Genus Sillaginodes
Evolution
A number of sillaginids have been identified from the fossil record, with the lower EoceneEocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
marking the first appearance of the family. The family is thought to have evolved
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
in the Tethys Sea of central Australia, before colonizing southern Australia during the upper Eocene after a seaway broke through south of Tasmania. During the Oligocene, the family spread to the north and south, occupying a much more extensive range than their current Indo-Pacific distribution. Fossils suggest the sillaginids ranged as far north as Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
and Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, and as far south as New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, found in shallow water sedimentary deposits along with other species of extant genera.
There have been at least eight fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
sillaginid species found, all of which are believed to be of the genus Sillago based on the only remains found; otolith
Otolith
An otolith, , also called statoconium or otoconium is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates. The saccule and utricle, in turn, together make the otolith organs. They are sensitive to gravity and linear acceleration...
s. Only one species of extant sillaginid, Sillago maculata, has been found in the fossil record, and this was in very recent Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
s.
- Sillago campbellensis (Schwarzhans, 1985) Australia, Miocene
- Sillago hassovicus (Koken, 1891) Poland, Middle Miocene
- Sillago maculata (Quoy and Gaimard, 1824) New Zealand, Middle Pleistocene
- Sillago mckayi (Schwarzhans, 1985) Australia, Oligocene
- Sillago pliocaenica (Stinton, 1952) Australia, Pliocene
- Sillago recta (Schwarzhans, 1980) New Zealand, Upper Miocene
- Sillago schwarzhansi (Steurbaut, 1984) France, Lower Miocene
- Sillago ventriosus (Steurbaut, 1984) France, Upper Oligocene
Phylogeny
The relationships of the Sillaginidae are poorly known, with very similar morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
characteristics and a lack of genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
studies restricting the ability to perform cladistic analyses on the family. Being the fossil sillaginids are based on the comparison of fossil otoliths, with no other type of remains found thus far, this also prevents the reconstruction of the evolution of the family through fossil species. While the position of the Sillaginidae in the order Perciformes is firmly established due to a number of synapomorphies shared with other members of the order, no sister group has been established for the family. The current taxonomic status of the family is thought to represent a basic picture of the group's phylogeny, with McKay further dividing the genus Sillago into three subgenera based on shared morphological characters of the swimbladder. The genera Sillaginodes and Sillaginopsis have the most plesiomorphic characteristics; being monotypic, and distinct from Sillago. Sillago is further divided into three subgenera based primarily on swim bladder morphology; Sillago, Parasillago and Sillaginopodys, which also represent evolutionary relationships. Whilst genetic studies have not been done on the family, they have been used to establish the relationship of what were thought to be various subspecies of school whiting, S. bassensis and S. flindersi. Furthermore, morphological data suggests a number of Australian species diverged very recently during the last glacial maximum
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
, which caused land bridge
Land bridge
A land bridge, in biogeography, is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonise new lands...
s to isolate population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
s of fish. The two aforementioned species of school whiting, S. maculata and S. burrus, and S. ciliata and S. analis are all thought to be products of such a process, although only the school whiting have anything other than similar morphology as evidence of this process.
Morphology
The Sillaginidae are medium sized fishes which grow to an average of around 20 cm and around 100 g, although the largest member of the family, the King George whiting is known to reach 72 cm and 4.8 kg in weightWeight
In science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...
. The body shape and fin placement of the family is quite similar to most of the members of the order Perciformes. Their bodies are elongate, slightly compressed, with a head that tapers toward a terminal mouth
Mouth
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 mouth has a band of brush-like teeth with canine teeth
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
present only in the upper jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
of Sillaginopsis. The cranial sensory system
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...
of the family is well developed above and laterally, with the lower jaw having a pair of small pores behind which is a median pit containing a pore on each side. On each side of the elongate head 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....
has a short sharp spine. They have two true 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 anterior one supported by 10 to 13 spines while the long rear one is held up by a single leading spine followed by 16 to 27 soft rays. The anal fin is similar to the second dorsal fin, having two small slender spines followed by 14 to 26 soft rays. Their bodies are covered in ctenoid scales
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...
, with the exception of the 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...
which may have cycloid or ctenoid scales. There is a wide variation in the amount of lateral line scales, ranging from 50 to 141. The swimbladder in the Sillaginidae is either absent, poorly developed, or highly complex with anterior and lateral extensions that project well into the caudal region. A unique duct
Duct (anatomy)
In anatomy and physiology, a duct is a circumscribed channel leading from an exocrine gland or organ.-Types of ducts:Examples include:-Duct system:...
-like process is present from the ventral surface of the swimbladder to just before the urogenital opening
Urogenital opening
The urogenital opening is where waste products of the body and reproductive fluids are expelled to the environment outside of the body cavity. In some organisms, including birds and many fish, discharge from the urological, digestive, and reproductive systems empty into a common sac called the...
in most species. The presence and morphology of each species' swim bladder is often their major diagnostic feature, with McKay's three proposed subgenera based on swimbladder morphology alone. The sillaginids have only a small range of body colourings and frequently the only colour characteristics to identify between species are the arrangements of spots and bars on their upper bodies. Most of the family are a pale brown – creamy white colour, while a few species are silver all over. The undersides of the fish are usually lighter than the upper side, and the fins range from yellow to transparent
Transparency and translucency
In the field of optics, transparency is the physical property of allowing light to pass through a material; translucency only allows light to pass through diffusely. The opposite property is opacity...
, often marked by bars and spots.
Distribution and habitat
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...
in the east, as well occupying as a number of small islands including 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...
in the 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...
. While they have a fairly wide distribution, the highest species densities occur along the coasts 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...
, 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...
, Taiwan, South East Asia, the Indonesian Archipelago and northern Australia
Northern Australia
The term northern Australia is generally known to include two State and Territories, being Queensland and the Northern Territory . The part of Western Australia north of latitude 26° south—a definition widely used in law and State government policy—is also usually included...
. One species of sillaginid, Sillago sihama, has been declared an invasive species
Invasive 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 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.
Sillaginids are primarily inshore marine fishes inhabiting stretches of coastal waters, although a few species move offshore in their adult stages to deep sand banks or reefs to a maximum known depth of 180 m. All species primarily occupy sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
y, 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 or mud
Mud
Mud is a mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone . When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds...
dy substrates, often using seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
or reef as cover. They commonly inhabit tidal flats, 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...
zones, broken bottoms and large areas of uniform substrate. Although the family is marine, many species inhabit estuarine environments, with some such as Sillaginopsis panijus also found in the upper reaches of the estuary. Each species often occupies a specific niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
to avoid competition
Interspecific competition
Interspecific competition, in ecology, is a form of competition in which individuals of different species compete for the same resource in an ecosystem...
with co-occurring sillaginids, often inhabiting a specific substrate type, depth, or making use of surf zones and estuaries. The juveniles often show distinct changes in habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
preference as they mature, often moving to deeper waters. No members of the family are known to undergo migratory movements, and have been shown to be relatively weak swimmers, relying on currents to disperse juveniles.
Diet and feeding
The smelt-whitings are benthic carnivoreCarnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
s, with all of the species whose diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
s have been studied showing similar prey preferences. Studies from the waters of 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...
, 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...
and Australia have shown that polychaetes, a variety of crustaceans, molluscs and to a lesser extent echinoderms and fish are the predominant prey items of the family. Commonly taken crustaceans include decapods
Decapoda
The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
, 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 and isopods, while the predominant molluscs taken are various species of bivalves, especially the unprotected siphon filters that protrude from the shells. In all species studied, some form of diet shift occurs as the fishes mature, often associated with a movement to deeper waters and thus to new potential prey. The juveniles often prey on planktonic prey, with small copepods, isopods and other small crustaceans often taken. Whilst many species have a change in niche to reduce intraspecific competition
Intraspecific competition
Intraspecific competition is a particular form of competition in which members of the same species vie for the same resource in an ecosystem...
, there are often many species of sillaginid inhabiting a geographical area. Where this occurs, there is often definite diet differences between species, often associated with a niche specialization. The sillaginid's distinctive body shape and mouth placement is an adaptation to bottom feeding, which is the predominant method of feeding for all whiting species. All larger whiting feed by using their protrusile jaws and tube-like mouths to suck up various types of prey from in, on or above the ocean substrate, as well as using their nose as a 'plough
Plough
The plough or plow is a tool used in farming for initial cultivation of soil in preparation for sowing seed or planting. It has been a basic instrument for most of recorded history, and represents one of the major advances in agriculture...
' to dig through the substrate.
There is a large body of evidence that shows whiting do not rely on visual cues when feeding, instead using a system based on the vibrations emitted by their prey.
Predators
Smelt-whitings are a major link in the food chainFood chain
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
of most systems, and frequently fall prey to a variety of aquatic
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
and aerial predators. Their main aquatic predators are a wide variety of larger fish, including both teleosts and a variety of shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s and ray
Stingray
The stingrays are a group of rays, which are cartilaginous fishes related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes, and consist of eight families: Hexatrygonidae , Plesiobatidae , Urolophidae , Urotrygonidae , Dasyatidae , Potamotrygonidae The...
s. Marine mammal
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...
s including seals
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...
and dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
s have been reported to have taken sillaginids as a main food source. Seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s are also another major predator of the family, with diving species such as Cormorant
Cormorant
The bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.- Names :...
s taking older fish in deeper waters while juvenile fish in shallow water fall prey to wading birds. Sillaginids are often called 'sandborers' due to their habit of burying themselves in the substrate to avoid predators, much in the same way as they forage, by ploughing their nose into the substrate. This defense is even used against human
Human
Humans are the only living species in the Homo genus...
fishermen, who frequently wade barefoot to feel for buried fish. The Sillaginidae are also host to a variety of well studied internal and external parasites, which are represented prominently by the groups Digenea
Digenea
Digenea is a subclass within the Platyhelminthes consisting of parasitic flatworms with a syncytial tegument and, usually, two suckers, one ventral and one oral. Adults are particularly common in the digestive tract, but occur throughout the organ systems of all classes of vertebrates...
, Monogenea
Monogenea
Monogenea are a group of largely ectoparasitic members of the flatworm phylum Platyhelminthes, class Monogenea.-Characteristics:Monogenea are very small parasitic flatworms mainly found on skin or gills of fish....
and Myxosporea
Myxosporea
The Myxosporea are a class of microscopic parasites, belonging to the Myxozoa. They have a complex life cycle which comprises vegetative forms in two hosts, an aquatic invertebrate and an ectothermic vertebrate, usually a fish. Each host releases a different type of spore...
, Copepoda and Nematoda.
Reproduction
The Sillaginidae are an oviparous, non guarding family, whose species tend to show similar reproductive patterns to one another. Each species reaches 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 slightly different age, with each sex often showing a disparity in time of maturation. Each species also spawns over a different season and the spawning season often differs within a species, usually as a function of latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
; a feature not unique to sillaginids. The proximity to shore of spawning is also different between species, as each species usually does not migrate
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
inshore to spawn, even if the juvenile
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
s require shallow water for protection, instead relying on currents. The fecundity of sillaginids is variable, with a normal range between 50 000 – 100 000. The eggs
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...
are small (0.6 to 0.8 mm), spherical and pelagic, hatching around 20 days after fertilisation
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...
. 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 are quite similar, requiring a trained developmental biologist to identify between species. The larvae and juveniles are at the mercy of the ocean current
Ocean current
An ocean current is a continuous, directed movement of ocean water generated by the forces acting upon this mean flow, such as breaking waves, wind, Coriolis effect, cabbeling, temperature and salinity differences and tides caused by the gravitational pull of the Moon and the Sun...
s, being too weaker swimmers to actively seek out coastlines. Currents are thought to have been responsible for the distribution of mainland
Mainland
Mainland is a name given to a large landmass in a region , or to the largest of a group of islands in an archipelago. Sometimes its residents are called "Mainlanders"...
species to offshore island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
s as well as the current widespread distribution of Sillago sihama. In all studied species, juveniles inhabit shallow waters in protected embayments, estuaries, tidal creek
Creek (tidal)
A tidal creek, tidal channel, or estuary is the portion of a stream that is affected by ebb and flow of ocean tides, in the case that the subject stream discharges to an ocean, sea or strait. Thus this portion of the stream has variable salinity and electrical conductivity over the tidal cycle...
s and lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
s as well as exposed surf zones, usually over tidal flats and seagrass beds. As the fish mature, they generally move to deeper waters, showing a change in diet.
Relationship to humans
The sillaginids are some of the most important commercial fishesFishery
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,...
in the Indo-Pacific region, with a few species making up the bulk of whiting catches. Their high numbers, coupled with their highly regarded 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:...
are the reason for this, and their inshore nature also has made them popular targets for 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...
in a number of countries. With 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....
rife in some areas, sustainable aquaculture
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
has allowed the commercial farming of a number of sillaginid species, as well as the use of farmed fish to restock depleted estuaries. At least one species, the Gangetic whiting, has occasionally been used in brackish water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
aquaria.
Commercial fisheries
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
generally include only those species taken in large numbers, but there are some species which make up significant numbers of the bycatch. To add to this problem, many of the lesser known species are taken by subsistence fisheries and not reported. From estimates by the FAO
Fão
Fão is a town in Esposende Municipality in Portugal....
, however, it is evident that the family is one of the most important in the Indo-Pacific region, having an estimated catch of 22 718 tonne
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...
s in 1990 alone. In this same report, it was shown that the greatest three utilizers of sillaginids were the Philippines, Western Australia and Thailand respectively. The records also suggested that the catch increased from 1983 when it was 17 570 t, up to the last estimate in 1990 of 22 718 t. No such estimates have been carried out since. Modern records for Australia show that this trend has reversed, with all catches from Australia totaling 4 372 t in 2006 compared with 1990's 6000 t haul. Statistics from other countries are unavailable for such comparison.
Sillaginids are taken by a variety of fishing methods, with inshore catches predominantly taken using beach seine nets and cast nets. Due to the alert nature of sillaginids, skill is required on creeping up quietly enough to be able to net fish with a cast net, with experienced fishers often paddling into the sun toward a school and drifting slowly upon it before casting the net. In deeper waters, commercial trawlers and longliners take the most fish, with a number of sillaginids taken in prawn trawls as bycatch. The fish are normally marketed fresh locally under various names, with "Ashuos" commonly used in many countries for various sillaginids. At least one export fishery exists in Australia whereby S. flindersi is exported to Thailand where the fish are repackaged and sent to Japan frozen.
Recreational fisheries
In Australia and Japan, members of the family are highly sought after by anglers for their sporting and eating qualities, with anglers often taking more than commercial fishermen in some areas. The fishing techniques for all sillaginids are quite similar, with the shallow habitats often requiring light line and quiet movements. Whiting are also popular in part due to their accessibility, with tidal flats around beaches, estuaries and jettiesJetty
A jetty is any of a variety of structures used in river, dock, and maritime works that are generally carried out in pairs from river banks, or in continuation of river channels at their outlets into deep water; or out into docks, and outside their entrances; or for forming basins along the...
common habitats from where many whiting species are caught without need for a boat. Tidal
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
movements also affect catches, as do lunar phases, causing whiting to 'bite' when the tide is changing. Tackle used is kept light to avoid spooking the fish, and often requires only a simple setup, with a hook
Fish hook
A fish hook is a device for catching fish either by impaling them in the mouth or, more rarely, by snagging the body of the fish. Fish hooks have been employed for centuries by fishermen to catch fresh and saltwater fish. In 2005, the fish hook was chosen by Forbes as one of the top twenty tools...
and light sinker
Sinker (fishing)
A fishing sinker or knoch is a weight used in conjunction with a fishing lure or hook to increase its rate of sink, anchoring ability, and/or casting distance. Fishing sinkers may be as small as 1/32 of an ounce for applications in shallow water, and even smaller for fly fishing applications, or as...
tied directly to the mainline usually effective. In deeper water fished from boats or where currents are strong, more complex rigs are used, often with hooks tied to dropper loops on the trace. in Australia, some specialist whiting fishermen who target the fish in the surf or on shallow banks use red bead
Bead
A bead is a small, decorative object that is usually pierced for threading or stringing. Beads range in size from under to over in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork...
s or tubing to attract the fish, claiming the method produces more fish. The bait used is normally anything from the surrounding environment which the whiting naturally prey on, with polychaetes, bivalves, crustaceans such as prawns and crabs, cephalopods and small fish effective for most species. As with most species, live bait is known to produce better catches. Lure fishing for whiting is not normally practiced, but saltwater flies
Fly fishing
Fly fishing is an angling method in which an artificial 'fly' is used to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. Casting a nearly weightless fly or 'lure' requires casting techniques significantly different from other forms of casting...
have been used to good effect, as have small soft plastic lures. In some areas, restrictions to the amount and size of fish are in place and enforced by fishery authorities.