The Gangetic whiting (''Sillaginopsis panijus''), also known as the Gangetic sillago or flathead sillago, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

inshore A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

marine and

estuarine fish Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than deep, it follows that pelagic coastal fish are generally epi ...

of the smelt-whiting family,

Sillaginidae The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family (biology), family of benthic coastal Marine (ocean), marine fish historically classified in the order (biology), order Percif ...

. It is the most distinctive

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

n member of the family due to its flattened head and trailing

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

s. Although first described in 1822, it was not placed in its own genus until 1861 when

Theodore Gill Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist, and librarian. Career Born and educated in New York City under private tutors, Gill early showed interest in natural hist ...

erected ''Sillaginopsis'', a genus which is still monotypic. Gangetic whiting are of minor commercial importance along the Southeast coast of the Asian continent where it inhabits protected areas.

Taxonomy and naming

The Gangetic whiting is the only species of the genus ''Sillaginopsis'', which itself is one of three genera the family

, containing all the smelt whitings. The Sillaginidae are part of the

Percoidei Percoidei is a suborder of bony fishes in the order Perciformes. Many commercially harvested fish species are considered to be contained in this suborder, including the groupers, Serranidae, seabasses and perches. Divisions The following classif ...

, a suborder of the order

Perciformes Perciformes (), also called the Acanthopteri, is an order or superorder of ray-finned fish in the clade Percomorpha. ''Perciformes'' means " perch-like". Among the well-known members of this group are perches and darters ( Percidae), and als ...

. The Gangetic whiting was originally named ''Cheilodipterus panijus'' in 1822 by

Francis Buchanan-Hamilton Francis Buchanan (15 February 1762 – 15 June 1829), later known as Francis Hamilton but often referred to as Francis Buchanan-Hamilton, was a Scottish surgeon, surveyor and botanist who made significant contributions as a geographer and zoolo ...

from a

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

taken from the

Ganges The Ganges ( ; in India: Ganga, ; in Bangladesh: Padma, ). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international which goes through India, Bangladesh, Nepal and China." is a trans-boundary rive ...

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

. The species was further examined by Gill in 1861 in the first review of the family, entitled "Synopsis of the Sillaginoids", which led to the creation of the genus ''Sillaginopsis''. This new classification changed the

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...

to the currently accepted ''Sillaginopsis panijus''.

Description

The distinct appearance of the Gangetic whiting makes it the easiest of the smelt whitings to identify. The

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

of the species is highly depressed, like that of the flatheads, with very small eyes well constricted by the

orbits In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificia ...

. The first

contains ten spines including a large trailing second spine; the second dorsal fin has one spine and 25 to 27 soft rays. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has two spines and 24 to 27 soft rays. There are 84 to 90

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...

and the species has a total of 42

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e. The species is known to grow to a length of 44 cm. Another unique feature of this species is its severe reduction or even absence of a

swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ (anatomy), organ in bony fish that functions to modulate buoyancy, and thus allowing the fish to stay at desired water depth without having to maintain lift ...

, which all other members of the family Sillaginidae possess. The Gangetic whiting also has a small mouth with a much shorter lower

jaw The jaws are a pair of opposable articulated structures 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 ...

than upper jaw, with the two

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

most teeth larger than the rest.

Distribution and habitat

The Gangetic whiting is found on the southern Asian coast from

Puducherry Puducherry or Pondicherry may refer to: Places in India * Puducherry (union territory), formerly known as Pondicherry ** Puducherry (city), capital of the union territory of Puducherry ** Puducherry district The Puducherry District, also know ...

in the east, northward along the

Coromandel Coast The Coromandel Coast is a coastal region along the southeastern front of the Indian peninsula. Its delimitations are numerous, but generally admitted to be bounded by the Krishna River, Krishna river River mouth, mouth to the north, the Bay of B ...

and the

Ganges delta The Ganges Delta (also known the Ganges-Brahmaputra Delta, the Sundarbans Delta or the Bengal Delta) is a river delta predominantly covering the Bengal region of the Indian subcontinent, consisting of Bangladesh and the Indian state of West Be ...

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

and occasionally as far south as the

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands. An archipelago may be in an ocean, a sea, or a smaller body of water. Example archipelagos include the Aegean Islands (the o ...

. The species is often found on

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension (chemistry), suspension with water. Silt usually ...

y or

mud Mud (, or Middle Dutch) is loam, silt or clay mixed with water. Mud is usually formed after rainfall or near water sources. Ancient mud deposits hardened over geological time to form sedimentary rock such as shale or mudstone (generally cal ...

dy substrates in shallow, open

bay A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a ''gulf'', ''sea'', ''sound'', or ''bight''. A ''cove'' is a small, ci ...

s and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

along the coast. Juveniles usually migrate into the upper reaches of estuaries for protection against

predation Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

by larger species.

Biology

Gut content analysis has found the Gangetic whiting consumes numerous small fish,

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

and

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s and

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

, with its small mouth size restricting the size of food portions. The Gangetic whiting is the only known species of fish to host the

intestinal parasite An intestinal parasite infection is a condition in which a parasite infects the gastro-intestinal tract of humans and other animals. Such parasites can live anywhere in the body, but most prefer the intestinal wall. Routes of exposure and inf ...

'' Dichelyne alatae'', found in specimens in

West Bengal West Bengal (; Bengali language, Bengali: , , abbr. WB) is a States and union territories of India, state in the East India, eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabi ...

, with a number of other parasites identified from it.

Otolith An otolith (, ' ear + , ', a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle (ear), utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule ...

and size-age composition studies by Krishnayya (1963) of the commercial catches from the

Hooghly River The Hooghly River (, also spelled ''Hoogli'' or ''Hugli'') is the westernmost distributary of the Ganges, situated in West Bengal, India. It is known in its upper reaches as the Bhagirathi. The Bhagirathi splits off from the main branch of the G ...

estuary and found that ''S. panijus'' probably

spawn Spawn or spawning may refer to: * Spawning, the eggs and sperm of aquatic animals Arts, entertainment and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** ''Spawn: Armageddon' ...

s twice a year during the periods of November to February and August to September. The juveniles migrate toward the upper reaches during March and April and during December where they remain for two to three months.

Sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized ...

is attained at a length of about 120 mm.

Relationship to humans

A local

fishery Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish far ...

exists along the coast of the

Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean. Geographically it is positioned between the Indian subcontinent and the Mainland Southeast Asia, Indochinese peninsula, located below the Bengal region. Many South Asian and Southe ...

primarily near or on the

river delta A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creat ...

s, with commercially important fish captured by nets and longlines in the Hooghly and Ganges delta. The Gangetic whiting is sold fresh in local

markets Market is a term used to describe concepts such as: *Market (economics), system in which parties engage in transactions according to supply and demand *Market economy *Marketplace, a physical marketplace or public market *Marketing, the act of sat ...

, rarely making its way to overseas markets. Juvenile ''Sillaginopsis panijus'' are also occasionally traded as

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuary ...

aquarium fish.

References

{{Taxonbar, from1=Q3229859, from2=Q106420336 Sillaginidae Fish of South Asia Fish described in 1822