Western school whiting
Encyclopedia
The western school whiting, Sillago vittata (also known as the banded whiting, golden whiting and bastard whiting), 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. Western school whiting are known to grow to 30 cm in length and 275 g in weight, although unconfirmed reports suggest this might be an underestimate. The western school whiting is distributed along the Western Australia
n coast from Maud Landing
in the north to Rottnest Island
in the south. The species inhabits both shallow inshore environments and waters to depths of 55 m. The species is a benthic predator
, taking a variety of crustacean
s, mollusc
s and echinoderm
s, and shows a change in diet with age and habitat
. S. vittata is a multiple spawner
, reproducing between December and February once it has reached one or two years of age. Juveniles inhabit protected inshore waters, moving offshore once they reach sexual maturity
. It is often found in association with other sillaginids and comprises a minor fraction of commercial whiting catches in Western Australia.
in the genus
Sillago
, which is one of three divisions of the smelt whiting family
Sillaginidae
. The smelt-whitings are Perciformes
in the suborder
Percoidei
.
The western school whiting was first scientifically described
by Roland McKay in 1985, who was the first to recognize it apart from Sillago bassensis
. McKay designated a specimen caught off north east Rottnest Island
to be the holotype
, also designating several paratype
s. The species is commonly referred to as the 'western school whiting' in Australian literature, causing confusion with Sillago bassensis, which was previously given this name before S. vittata was described. It is also known as the 'banded whiting' and 'golden whiting' in reference to its colouring, as well as the 'bastard whiting' by fishermen
. The specific name, vittata is derived from the Latin 'vittatus', meaning 'banded'.
morphology the best identification features. The species is known to reach a maximum length of 30 cm and 275 g,
although unconfirmed reports from Shark Bay
indicate they may grow significantly larger. The external morphology is similar to all sillaginids, having a fairly straight ventral profile and a slightly curved dorsal profile. The dorsal fin
is composed of two sections, the first consisting of 11 spines, while the second, longer dorsal has a single spine followed by 17 to 19 soft rays posteriorally. The anal fin has two spines and is followed by 16 to 18 soft rays. The scales
are ctenoid in nature except for the cheek scales, of which there are 3 rows, the upper being cycloid and the lower 2 ctenoid. There are 65 to 70 lateral line
scales and 32 to 34 vertebrae in total.
The swimbladder is very similar to S. bassensis and S. robusta, with a median anterior extension and very poorly developed anterolateral projections. The posterior median projection is short and a duct like process connects to the ventral surface of the swimbladder.
The western school whiting's head and upper body are tan above, becoming paler below with a silvery white belly
surface. In life blue, mauve
and yellow reflections are common. In larger, albeit unconfirmed, specimens taken at Shark Bay the colour was a golden yellow shade all over, still having the species characteristic banding. There 8 to 11 of these rusty brown to dark brown bars running oblique
ly on the sides of the fish, often overlapping a distinct silvery white laterally positioned band. This band begins behind the operculum
and continues to the caudal fin base. The spinous dorsal fin is whitish below grading to yellow above, with brown spots and black dusting apical
ly. The second dorsal fin is white basally, becoming lemon yellow above with 3 rows of black blotches forming longitudinal
lines across the fin. The anal fin is bright yellow with white margins, the ventral
s have a pale yellow center with white margins and the caudal is yellow. The pectoral fin is pale lemon yellow to hyaline
with a large round dark brown to bluish brown spot just the base of the fin.
s of Western Australia
, inhabiting a known range from Maud Landing in the north to Rottnest Island
, off Perth
, in the south. Reports of an unconfirmed 'narrow-barred whiting' off the coast of Fremantle
may also refer to S. vittata, which would extend its range further south. The species inhabits both shallow inshore waters, as well as deeper waters on the continental shelf
up to 55 m deep. In shallower waters it inhabits weed
banks, coral reef
and sand
y substrates including beach
es, often mingling with other species of sillaginids. Systematic studies in lower Western Australia found the species to be most common between 5 and 15 m deep, attributing this to the need for the juveniles to migrate to deeper areas as they mature.
and the Western Australian Marine Research Laboratories. Western school whiting, as their name suggests, are a schooling species, often mingling with other species of sillaginid. In shallower waters, they are often associated with Sillago burrus
, Sillago schomburgkii and Sillago analis
, while in deeper offshore waters they are often found with Sillago robusta, Sillago bassensis and Sillago burrus.
s, mollusc
s, crustacean
s and other fish. Dietary studies on the species have demonstrated the dominant components of its diet are errant polychaetes, copepod
s from the cladocera
n and calanoid
orders,
amphipods
and ophiuroid
echinoderm
s. Other lesser taken types of food include sedentary polychaetes, harpacticoid
s, cumacea
ns, bivalve
s and teleost
s. Studies also show both geographical and seasonal variability, with the habitat type the main influence on diet. Although habitat strongly controls diet, the age of the individuals also partly determines their diet. Although only a minor change in diet is observed as size increases, dietary breadth increased; that is more different types of prey were taken, with younger fish often, but not always, targeting one specific prey type. In general, juveniles take more copepods with adult diets more amphipod and polychaete dominated. Teleosts were only consumed by larger individuals. This pattern is not seen in all populations of fish, with geographic variation having major impacts on all aspects of diet.
Significant dietary overlaps with a number of co-occurring species of sillaginids is seen in both juvenile and adult stages in different environments. Young fish in their shallow, protected environments show overlap with young S. burrus, S. schomburgkii and Sillaginodes punctatus
in their preference for copepods, although the timing of spawining events somewhat decreases this competition. In deeper nearshore waters, there is minor overlap with S. bassensis, but significant differences reduce interspecific competition
.
As is the case with other sillaginids, their possession of protrusile jaw
s and a tube-like mouth are ideal for suction
feeding on a wide variety of prey that occur on and in the substrate. Measurements of mouth dimensions suggest S. vittata is able to extend its jaws further downward compared to co-occurring species, which may answer why it consumes more polychaetes than these species.
until the end of the first year of its life in deeper waters, while population
s that inhabit nearshore waters don't fully reach maturity until the end of the second year. All male fish are mature by the time they reach 130 mm in length and 160 mm in female fish. The species spawn
s in deeper waters during a period between December and February, with a peak in early January. Anatomical evidence suggests S. vittata is a batch spawner, releasing eggs in batches over a period during the spawning months, possibly to buffer against adverse environmental factors. juvenile
s reside in protected inshore waters such as bay
s and mangrove
swamp
s until they reach sexual maturity, when they move offshore to spawn. Western school whiting usually reach 2 years of age, with some individuals surviving up to 7 years, allowing each fish to spawn multiple times throughout its life. The species reaches 30 cm at its maximum length.
developed around it. The first is off Rottnest Island
, where it is trawl
ed in deeper offshore waters, and also in Shark Bay
, where it is one of a number of sillaginids landed. In Shark Bay it can comprise up to 20% of the entire whiting catch, with fishermen giving it the name 'bastard whiting' as large numbers of S. vittata mean lower numbers of their targeted species. Of the approximately 177 000 kg of whiting taken in Western Australia, less than 2152 kg of this is attributable to S. vittata, making it one of the less important fisheries to the state.
Despite the reactions of professional fishermen, western school whiting are considered to have good to excellent flesh for eating
, and fetch similar high prices at market
to other whiting species. Due to their offshore nature in the south of Western Australia, they are rarely taken by recreational fishermen
, while in the northern part of their range where they inhabit shallower waters, they are often overlooked for larger tropical species by anglers. Thus they are not a major recreational fishery either. They respond to the same fishing styles as other whitings, generally using light lines
and sinkers with worm or mollusc baits. They are caught off beaches, jetties
and from boats. There is no size restriction on the species, but a daily bag limit of 40 per person applies.
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 benthic
Benthic zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such...
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...
in 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 species is one of three 'school whiting' that inhabit southern Australia
Southern Australia
The term southern Australia is generally considered to include the States and territories of Australia of New South Wales, Victoria, South Australia, Tasmania and the Australian Capital Territory...
and share a very similar appearance. Western school whiting are known to grow to 30 cm in length and 275 g in weight, although unconfirmed reports suggest this might be an underestimate. The western school whiting is distributed along the Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
n coast from Maud Landing
Coral Bay, Western Australia
Coral Bay is a small town on the coast of Western Australia, 1,200 km north of Perth. It exists primarily for tourism, with a side industry of fishing...
in the north to Rottnest Island
Rottnest Island
Rottnest Island is located off the coast of Western Australia, near Fremantle. It is called Wadjemup by the Noongar people, meaning "place across the water". The island is long, and at its widest point with a total land area of . It is classified as an A Class Reserve and is managed by the...
in the south. The species inhabits both shallow inshore environments and waters to depths of 55 m. The species is a benthic predator
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
, taking 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, mollusc
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
s and 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 shows a change in diet with age and 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...
. S. vittata is a multiple spawner
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...
, reproducing between December and February once it has reached one or two years of age. Juveniles inhabit protected inshore waters, moving offshore once they reach sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
. It is often found in association with other sillaginids and comprises a minor fraction of commercial whiting catches in Western Australia.
Taxonomy and naming
The western school whiting is one of 29 speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Sillago
Sillago
Sillago is one of three genera in the family Sillaginidae containing the smelt-whitings, and contains 29 species, making Sillago the only non-monotypic genus in the family. Distinguishing among Sillago species can be difficult, with many similar in appearance and colour, forcing the use of swim...
, which is one of three divisions of the smelt whiting family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Sillaginidae
Sillaginidae
The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fishes in the order Perciformes. The smelt-whitings inhabit a wide region covering much of the Indo-Pacific, from the west coast of Africa east to Japan...
. The smelt-whitings are Perciformes
Perciformes
The Perciformes, also called the Percomorphi or Acanthopteri, is one of the largest orders of vertebrates, containing about 40% of all bony fish. Perciformes means perch-like. They belong to the class of ray-finned fish and comprise over 7,000 species found in almost all aquatic environments...
in the suborder
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...
Percoidei
Percoidei
Percoidei is one of eighteen suborders of bony fish in the order Perciformes. Many commercially harvested fish species are contained in this suborder, including the snappers, jacks, whitings, groupers, bass, perches and porgies.-Divisions:...
.
The western school whiting was first scientifically described
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
by Roland McKay in 1985, who was the first to recognize it apart from Sillago bassensis
Southern school whiting
The 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...
. McKay designated a specimen caught off north east Rottnest Island
Rottnest Island
Rottnest Island is located off the coast of Western Australia, near Fremantle. It is called Wadjemup by the Noongar people, meaning "place across the water". The island is long, and at its widest point with a total land area of . It is classified as an A Class Reserve and is managed by the...
to be the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, also designating several paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
s. The species is commonly referred to as the 'western school whiting' in Australian literature, causing confusion with Sillago bassensis, which was previously given this name before S. vittata was described. It is also known as the 'banded whiting' and 'golden whiting' in reference to its colouring, as well as the 'bastard whiting' by fishermen
Fisherman
A fisherman or fisher is someone who captures fish and other animals from a body of water, or gathers shellfish. Worldwide, there are about 38 million commercial and subsistence fishermen and fish farmers. The term can also be applied to recreational fishermen and may be used to describe both men...
. The specific name, vittata is derived from the Latin 'vittatus', meaning 'banded'.
Description
The western school whiting is similar in appearance to a number of geographically overlapping sillaginids, with colouring and swimbladderGas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
morphology the best identification features. The species is known to reach a maximum length of 30 cm and 275 g,
although unconfirmed reports from Shark Bay
Shark Bay, Western Australia
Shark Bay is a World Heritage Site in the Gascoyne region of Western Australia. It is an area centred approximately on , 800 kilometres north of Perth, on the westernmost point of Australia. An expedition led by Dirk Hartog happened upon the area in 1616, becoming the second group of Europeans...
indicate they may grow significantly larger. The external morphology is similar to all sillaginids, having a fairly straight ventral profile and a slightly curved dorsal profile. The 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...
is composed of two sections, the first consisting of 11 spines, while the second, longer dorsal has a single spine followed by 17 to 19 soft rays posteriorally. The anal fin has two spines and is followed by 16 to 18 soft rays. The 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...
are ctenoid in nature except for the cheek scales, of which there are 3 rows, the upper being cycloid and the lower 2 ctenoid. There are 65 to 70 lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
scales and 32 to 34 vertebrae in total.
The swimbladder is very similar to S. bassensis and S. robusta, with a median anterior extension and very poorly developed anterolateral projections. The posterior median projection is short and a duct like process connects to the ventral surface of the swimbladder.
The western school whiting's head and upper body are tan above, becoming paler below with a silvery white belly
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
surface. In life blue, mauve
Mauve
Mauve is a pale lavender-lilac color, one of many in the range of purples. The color mauve is named after the mallow flower....
and yellow reflections are common. In larger, albeit unconfirmed, specimens taken at Shark Bay the colour was a golden yellow shade all over, still having the species characteristic banding. There 8 to 11 of these rusty brown to dark brown bars running oblique
Angle
In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
ly on the sides of the fish, often overlapping a distinct silvery white laterally positioned band. This band begins behind 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....
and continues to the caudal fin base. The spinous dorsal fin is whitish below grading to yellow above, with brown spots and black dusting apical
Apex
Apex may refer to:- Biology :* Apex , the tip of the spire of the shell of a gastropod* Apex is the Apical meristem or its remnant on a flower...
ly. The second dorsal fin is white basally, becoming lemon yellow above with 3 rows of black blotches forming longitudinal
Anatomical terms of location
Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...
lines across the fin. The anal fin is bright yellow with white margins, the ventral
Fish anatomy
Fish anatomy is primarily governed by the physical characteristics of water, which is much denser than air, holds a relatively small amount of dissolved oxygen, and absorbs more light than air does.- Body :...
s have a pale yellow center with white margins and the caudal is yellow. The pectoral fin is pale lemon yellow to 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...
with a large round dark brown to bluish brown spot just the base of the fin.
Distribution and habitat
The western school whiting is only known from the coastCoast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
s of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, inhabiting a known range from Maud Landing in the north to Rottnest Island
Rottnest Island
Rottnest Island is located off the coast of Western Australia, near Fremantle. It is called Wadjemup by the Noongar people, meaning "place across the water". The island is long, and at its widest point with a total land area of . It is classified as an A Class Reserve and is managed by the...
, off Perth
Perth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....
, in the south. Reports of an unconfirmed 'narrow-barred whiting' off the coast of Fremantle
Fremantle, Western Australia
Fremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...
may also refer to S. vittata, which would extend its range further south. The species inhabits both shallow inshore waters, as well as deeper waters on the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
up to 55 m deep. In shallower waters it inhabits weed
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
banks, coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
and 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 substrates including 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, often mingling with other species of sillaginids. Systematic studies in lower Western Australia found the species to be most common between 5 and 15 m deep, attributing this to the need for the juveniles to migrate to deeper areas as they mature.
Biology
The biology and ecology of the western school whiting is relatively well known due to a series of studies conducted by researchers at Murdoch UniversityMurdoch University
Murdoch University is a public university based in Perth, Australia. It began operations as the state's second university in 1973, and accepted its first students in 1975...
and the Western Australian Marine Research Laboratories. Western school whiting, as their name suggests, are a schooling species, often mingling with other species of sillaginid. In shallower waters, they are often associated with Sillago burrus
Western trumpeter whiting
The 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 schomburgkii and Sillago analis
Golden lined whiting
The 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...
, while in deeper offshore waters they are often found with Sillago robusta, Sillago bassensis and Sillago burrus.
Diet and feeding
The western school whiting is a benthic predator, taking a variety of 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...
s, mollusc
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
s, 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 and other fish. Dietary studies on the species have demonstrated the dominant components of its diet are errant polychaetes, 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 from the cladocera
Cladocera
Cladocera is an order of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed. They are ubiquitous in inland aquatic habitats, but rare in the oceans. Most are long, with a down-turned head, and a carapace covering the apparently...
n and calanoid
Calanoida
Calanoida is an order of copepods, a kind of zooplankton. They include around 40 families with about 1800 species of both marine and freshwater copepods. Calanoid copepods are dominant in the plankton in many parts of the world's oceans, making up 55%–95% of plankton samples...
orders,
amphipods
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
and ophiuroid
Brittle star
Brittle stars or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the seafloor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to in length on the largest specimens...
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. Other lesser taken types of food include sedentary polychaetes, harpacticoid
Harpacticoida
Harpacticoida is an order of copepods, in the Subphylum Crustacea. This order comprises 463 genera and about 3,000 species. Members of it are benthic copepods found throughout the world in the marine environment and in fresh water...
s, cumacea
Cumacea
Cumacea is an order of small marine crustaceans, occasionally called hooded shrimp. Their unique appearance and uniform body plan makes them easy to distinguish from other crustaceans.-Anatomy:...
ns, bivalve
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
s and teleost
Teleostei
Teleostei is one of three infraclasses in class Actinopterygii, the ray-finned fishes. This diverse group, which arose in the Triassic period, includes 20,000 extant species in about 40 orders; most living fishes are members of this group...
s. Studies also show both geographical and seasonal variability, with the habitat type the main influence on diet. Although habitat strongly controls diet, the age of the individuals also partly determines their diet. Although only a minor change in diet is observed as size increases, dietary breadth increased; that is more different types of prey were taken, with younger fish often, but not always, targeting one specific prey type. In general, juveniles take more copepods with adult diets more amphipod and polychaete dominated. Teleosts were only consumed by larger individuals. This pattern is not seen in all populations of fish, with geographic variation having major impacts on all aspects of diet.
Significant dietary overlaps with a number of co-occurring species of sillaginids is seen in both juvenile and adult stages in different environments. Young fish in their shallow, protected environments show overlap with young S. burrus, S. schomburgkii and Sillaginodes punctatus
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...
in their preference for copepods, although the timing of spawining events somewhat decreases this competition. In deeper nearshore waters, there is minor overlap with S. bassensis, but significant differences reduce interspecific 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...
.
As is the case with other sillaginids, their possession of protrusile 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...
s and a tube-like mouth are ideal for suction
Suction
Suction is the flow of a fluid into a partial vacuum, or region of low pressure. The pressure gradient between this region and the ambient pressure will propel matter toward the low pressure area. Suction is popularly thought of as an attractive effect, which is incorrect since vacuums do not...
feeding on a wide variety of prey that occur on and in the substrate. Measurements of mouth dimensions suggest S. vittata is able to extend its jaws further downward compared to co-occurring species, which may answer why it consumes more polychaetes than these species.
Reproduction and growth
The western school whiting does not 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...
until the end of the first year of its life in deeper waters, while 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 that inhabit nearshore waters don't fully reach maturity until the end of the second year. All male fish are mature by the time they reach 130 mm in length and 160 mm in female fish. The species spawn
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...
s in deeper waters during a period between December and February, with a peak in early January. Anatomical evidence suggests S. vittata is a batch spawner, releasing eggs in batches over a period during the spawning months, possibly to buffer against adverse environmental factors. 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 reside in protected inshore waters such as bay
Headlands and bays
Headlands and bays are two related features of the coastal environment.- Geology and geography :Headlands and bays are often found on the same coastline. A bay is surrounded by land on three sides, whereas a headland is surrounded by water on three sides. Headlands are characterized by high,...
s and 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...
swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s until they reach sexual maturity, when they move offshore to spawn. Western school whiting usually reach 2 years of age, with some individuals surviving up to 7 years, allowing each fish to spawn multiple times throughout its life. The species reaches 30 cm at its maximum length.
Relationship to humans
Western school whiting are taken in relatively small quantities in comparison to other western Australian sillaginids such as Sillago schomberkii and Sillaginodes punctatus, but has a few minor fisheriesFishery
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,...
developed around it. The first is off Rottnest Island
Rottnest Island
Rottnest Island is located off the coast of Western Australia, near Fremantle. It is called Wadjemup by the Noongar people, meaning "place across the water". The island is long, and at its widest point with a total land area of . It is classified as an A Class Reserve and is managed by the...
, where it is trawl
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....
ed in deeper offshore waters, and also in Shark Bay
Shark Bay, Western Australia
Shark Bay is a World Heritage Site in the Gascoyne region of Western Australia. It is an area centred approximately on , 800 kilometres north of Perth, on the westernmost point of Australia. An expedition led by Dirk Hartog happened upon the area in 1616, becoming the second group of Europeans...
, where it is one of a number of sillaginids landed. In Shark Bay it can comprise up to 20% of the entire whiting catch, with fishermen giving it the name 'bastard whiting' as large numbers of S. vittata mean lower numbers of their targeted species. Of the approximately 177 000 kg of whiting taken in Western Australia, less than 2152 kg of this is attributable to S. vittata, making it one of the less important fisheries to the state.
Despite the reactions of professional fishermen, western school whiting are considered to have good to excellent flesh for eating
Fish (food)
Fish is a food consumed by many species, including humans. The word "fish" refers to both the animal and to the food prepared from it. Fish has been an important source of protein for humans throughout recorded history.-Terminology:...
, and fetch similar high prices at market
Market
A market is one of many varieties of systems, institutions, procedures, social relations and infrastructures whereby parties engage in exchange. While parties may exchange goods and services by barter, most markets rely on sellers offering their goods or services in exchange for money from buyers...
to other whiting species. Due to their offshore nature in the south of Western Australia, they are rarely taken 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...
, while in the northern part of their range where they inhabit shallower waters, they are often overlooked for larger tropical species by anglers. Thus they are not a major recreational fishery either. They respond to the same fishing styles as other whitings, generally using light lines
Fishing line
A fishing line is a cord used or made for angling. Important parameters of a fishing line are its length, material, and weight...
and sinkers with worm or mollusc baits. They are caught off beaches, jetties
Jetty
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...
and from boats. There is no size restriction on the species, but a daily bag limit of 40 per person applies.