Temporal range: 33.9–0Ma Early Oligocene to Present
G. Cuvier, 1817
Sillago is one of five genera in the family Sillaginidae containing the smelt-whitings, and contains 31 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 bladder morphology as a definitive feature. All whiting species are benthic in nature and generally coastal fish, living in shallow, protected waters, although there are exceptions. Minor fisheries exist around various species of Sillago, making them of minor importance in most of their range.
The genus Sillago is one of five genera in the family Sillaginidae, itself part of the Percoidea, a suborder of the Perciformes. The name Sillago was first coined by famed taxonomist Georges Cuvier as a genus for his newly described species, Sillago acuta, which was later found to be a junior synonym of S. sihama. John Richardson placed the genus, along with Sillaginodes and Sillaginopsis in a family, which he named the Sillaginidae in 1846. Many species, both valid and invalid were added to the genus, and it was not until 1985 when Roland McKay of the Queensland Museum published a revision of the family Sillaginidae that the complex relationships between these names was cleared up. McKay further divided Sillago into three subgenera based primarily on the morphology of the swim bladder.
- Sillago: A double post-coelomic extension penetrating the tail region
- Parasillago: A single post-coelomic extension of the swimbladder
These subgenera are not universally accepted; for example, FishBase does not currently use them.
There are currently 31 recognized species in this genus:
- Sillago aeolus D. S. Jordan & Evermann, 1902 (Oriental sillago)
- Sillago analis Whitley, 1943 (Golden-lined sillago)
- Sillago arabica McKay & McCarthy, 1989 (Arabian sillago)
- Sillago argentifasciata C. Martin & H. R. Montalban, 1935 (Silver-banded sillago)
- Sillago asiatica McKay, 1982 (Asian sillago)
- Sillago attenuata McKay, 1985 (Slender sillago)
- Sillago bassensis G. Cuvier, 1829 (Western school sillago)
- Sillago boutani Pellegrin, 1905 (Boutan's sillago)
- Sillago burrus Richardson, 1842 (Western trumpeter sillago)
- Sillago caudicula Kaga, Imamura, Nakaya, 2010
- Sillago ciliata G. Cuvier, 1829 (Sand sillago)
- Sillago erythraea G. Cuvier, 1829
- Sillago flindersi McKay, 1985 (Flinders' sillago)
- Sillago indica McKay, Dutt & Sujatha, 1985 (Indian sillago)
- Sillago ingenuua McKay, 1985 (Bay sillago)
- Sillago intermedius Wongratana, 1977 (Intermediate sillago)
- Sillago japonica Temminck & Schlegel, 1843 (Japanese sillago)
- Sillago lutea McKay, 1985 (Mud sillago)
- Sillago maculata Quoy & Gaimard, 1824 (Trumpeter sillago)
- Sillago megacephalus S. Y. Lin, 1933 (Large-headed sillago)
- Sillago microps McKay, 1985 (Small-eyed sillago)
- Sillago nierstraszi Hardenberg, 1941 (Rough sillago)
- Sillago parvisquamis T. N. Gill, 1861 (Small-scale sillago)
- Sillago robusta Stead, 1908 (Stout sillago)
- Sillago schomburgkii W. K. H. Peters, 1864 (Yellowfin sillago)
- Sillago sihama Forsskål, 1775 (Silver sillago)
- Sillago sinica T. X. Gao, D. P. Ji, Y. S. Xiao, T. Q. Xue, Yanagimoto & Setoguma, 2011 (Chinese sillago)
- Sillago soringa Dutt & Sujatha, 1982 (Soringa sillago)
- Sillago suezensis Golani, R. Fricke & Tikochinski, 2013 
- Sillago vincenti McKay, 1980 (Vincent's sillago)
- Sillago vittata McKay, 1985 (Banded sillago)
All species in the genus Sillago are similar to other members of the Sillaginidae family in profile, with the distinctive compressed, long, tapering body common to all species. The definitive characteristic for Sillago is the presence of a swim bladder. Their swim bladders are often complex, further distinguishing them from the genera Sillaginodes and Sillaginopsis (which often lacks a swim bladder entirely).
Members of the genus usually have a silver to gold-brown colour depending on their habitat, with shallow sand flat fish having a more silver appearance, while estuary and silt bottom dwellers having a darker brown colour.
Distribution and habitat
With 31 species, the genus Sillago has the widest distribution of any smelt-whiting genus, spanning much of the Indo-Pacific. The genus ranges from the east coast of Africa to Japan in the east and Southern Australia in the south, with most species concentrated around South East Asia, the Indonesian Archipelago and Australia. Many species have overlapping distribution, often making positive identification hard.
Sillagos are generally coastal fish, inhabiting a variety of shallow water habitats including open sand flats, muddy substrates and beaches with moderately strong wave action. Some species enter estuaries and even penetrate fresh water for considerable periods, especially during vulnerable stages of their life cycle. Shallow water of a few centimetres is also occupied by juvenile sillagos, especially in the vicinity of cover such as seagrass beds or mangroves. A few species are known to inhabit deeper offshore waters, with fish known from trawls up to 180 m (600 ft) deep.
Relationship to humans
Various species of Sillago represent minor local fisheries in their ranges, with many having commercial importance. Fish are taken by a variety of methods including seine, gill and cast nets as well as by line. Recreational fishing for Sillago is common, especially in Australia where they are valued as food fish or for live bait for larger species. Estuarine aquaculture in India, Japan and Taiwan has utilized sillagos as an important species, and similar trials have been conducted in Australia. They can be very delicious when deep fried.
- Sepkoski, J. (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology, 364: 560.
- McKay, R.J. (1985). "A Revision of the Fishes of the Family Sillaginidae". Memoirs of the Queensland Museum, 22 (1): 1–73.
- Froese, Rainer, and Daniel Pauly, eds. (2014). Species of Sillago in FishBase. November 2014 version.
- Great Barrier Reef Marine Park Authority. "Whitsunday Plan of Management Area boundary map".
- Golani, D., Fricke, R. & Tikochinski, Y. (2013): Sillago suezensis, a new whiting from the northern Red Sea, and status of Sillago erythraea Cuvier (Teleostei: Sillaginidae). Journal of Natural History, 48 (7-8) : 413-428.
- McKay, R.J. (1992). FAO Species Catalogue: Vol. 14. Sillaginid Fishes Of The World (PDF). Rome: Food and Agricultural Organisation. pp. 19–20. ISBN 92-5-103123-1.