Small-scale whiting

Taxobox
name = Small-scale whiting
status = LC

---

image_width = 240px
image_caption =
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Perciformes
subordo = Percoidei
superfamilia = Percoidea
familia = Sillaginidae
genus = "Sillago"
species = "S. parvisquamis"
binomial = "Sillago parvisquamis"
binomial_authority = Gill, 1861
range_

range_map_width = 240px
range_map_caption = Approximate range of the small-scale whitingThe small-scale whiting, "Sillago parvisquamis" (also known as the blue whiting), 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 fin compared to 11 in all other species. The species is distributed through parts of the west Pacific Ocean including Japan, Taiwan, Korea and India, inhabiting the tidal flats of major estuaries. It is a benthic predator taking crustaceans, molluscs and annelids. Spawning in the species takes place from May to September, with peaks identified in June and July. The eggs and larvae have been extensively studied in order to distinguish them from the more abundant "Sillago sihama". Minor fisheries exist for the small-scale whiting, although it is thought be endangered by habitat loss and pollution, but has not been recognised as such by the IUCN.

Taxonomy and naming

The small-scale whiting is a member of the genus "Sillago", which contain 29 other species. It is part of the Sillaginidae family which is a division of the Percoidei, a suborder of the Perciformes. [ITIS | ID = 646053 | taxon = Sillago parvisquamis | year = 2007 | date = 15 October]

The species was first scientifically described by Theodore Gill in 1861 in the first review of the sillaginid fishes; "Synopsis of the Sillaginoids". The type specimen was taken from the waters of Kanagawa, near Yokohama in Japan.cite journal |last=McKay |first=R.J. |year=1985 |title=A Revision of the Fishes of the Family Sillaginidae |journal=Memoirs of the Queensland Museum |volume=22 |issue=1 |pages=1–73 |doi=] There has only been one formal misidentification, made by Peter Forsskål in 1913 when he mistook the species for "Sillago sihama". The name "small-scale whiting" is in reference to the species' smaller than average scales amongst the genus "Sillago".

Description

The small-scale whiting is very similar in external appearance to many other members of the genus "Sillago", which have a slightly compressed, elongate body tapering toward the terminal mouth. cite book | last = McKay | first = R.J. | coauthors = | title = FAO Species Catalogue: Vol. 14. Sillaginid Fishes Of The World | publisher = Food and Agricultural Organisation | date = 1992 | url = ftp://ftp.fao.org/docrep/fao/009/t0538e/t0538e06.pdf | location = Rome | pages = 19-20 | isbn = 92-5-103123-1 ] The dorsal fin is in two parts, the first made of feeble spines and the second of soft rays headed by a single feeble spine. The first dorsal fin has either 12 or 13 dorsal spines, a feature unique among "Sillago" which otherwise have 11 dorsal spines. The second dorsal fin has a single spine followed by 20 to 22 soft rays, while the anal fin has 2 spines and 22 or 24 soft rays. Other distinguishing features include 79 to 84 lateral line scales and 39 to 40 vertebrae, while the swimbladder morphology also is a highly distinguishing feature. The maximum known size of the species is 30 cm.

The swimbladder has two anterior extensions that arise medially, diverge and terminate. Two lateral extensions appear anteriorally, each with a blind tubule which curves to the abdominal walls and becomes a complex network of blind tubules. There are two posterior tapering extensions that project into and terminate into the caudal region. A duct like process is present from the lateral surface to the urogenital opening. This configuration is very similar to "S. sihama", except that the lateral tubules are more complex than in "S. sihama".

The small-scale whiting is a pale brown to dull brown colour above and lighter below with a faint mid-lateral band normally present. The fins are all hyaline in appearance except for the dorsal fin which becomes dusky terminally with 5 or 6 rows of dusky spots on the soft dorsal fin membrane.

Distribution and habitat

The small-scale whiting occupies a fairly restricted range in the northwest Pacific Ocean consisting of southern Japan, Taiwan, Koreacite journal | last = Ik-Soo | first = Kim | coauthors = Lee, Wan-O | title = New record of the Sillaginid Fish, Sillago parvisquamis (Pisces: Sillaginidae) from Korea | journal = Korean Journal of Zoology | volume = 39 | issue = 1 | pages = 21–25 | date = 1996 | id = ISSN 0440-2510 | accessdate =2007-12-22 ] and India. [cite journal | last = Dutt | first = S. | coauthors = Sujatha, K. | title = On the seven species of fishes of the family Sillaginidae from Indian waters | journal = Mahasagar | volume = 13 | issue = 4 | pages = 371–375 | date = 1980 | id = ISSN 0542-0938 | accessdate =2007-12-22 ] In Japan the species is known from the southern half of the island chain below Tokyo in the west and Yokohama in the east. The species is rare in both Korea and India, with only a single reported capture of the species in these countries. The species inhabits waters from 0 to 30 m in depth, often found on well developed tidal flats in the estuaries of large rivers. The larvae and juveniles of the species commonly inhabit these environments also, with juveniles often inhabiting the shallowest parts of the tidal flats. [cite journal | last = Imoto | first = Hasaya | coauthors = Seiichi Matsui, Norio Onikura, Erika Araki | title = Occurrence of larval and juvenile blue whiting Sillago parvisquamis in the estuary of Ima and Nagao Rivers of north eastern Kyushu, Japan | journal = Nippon Suisan Gakkaishi | volume = 65 | issue = 4 | pages = 753–754 | date = 1999 | id = ISSN 0021-5392 | accessdate = 2007-12-22 ]

Biology

Like other sillaginids, "S. parvisquamis" is a benthic predator and is known to consume a variety of crustaceans, molluscs and annelid worms.FishBase species | genus = Sillago | species = parvisquamis | year = 2007 | month = Dec ] Studies in the Buzen Sea of Japan have found the small-scale whiting spawns from May to July, while laboratory studies have similarly found that spawning occurs from May to September with a peak from June to July. [cite journal | last = Imoto | first = H. | coauthors = Yoshioka, C. Kitajima, and S. Matsui | title = The age and growth of blue whiting, "Sillago parvisquamis" distributed in the coastal waters of north eastern Kyushu | journal = Bull. Japan. Soc. Sci. Fish. | volume = 63 | issue = | pages = 892–898 | date = 1997 | id = | accessdate = 2007-12-22 ] Laboratory conditions also showed that spawning occurs at night predominantly between 20:30 and 22:00 hours.cite journal | last = Imoto | first = Hisaya | coauthors = Seiichi Matsui | title = Development of eggs, larvae and juveniles of laboratory reared blue whiting, "Sillago parvisquamis" (Percoidei:Sillaginidae) | journal = Ichthyological Research | volume = 47 | issue = 1 | pages = 59–67 | publisher = The Ichthyological Society of Japan | date = 2000 | doi = 10.1007/BF02674314 | id = ISSN 1341-8998 | accessdate =2007-12-22 ] The eggs are buoyant and spherical in shape with an average diameter of 0.71 mm and are transparent and colourless. Larval and juvenile development has been extensively described by Imoto and Matsui (2000), with a number of characteristics including higher numbers of myomeres and melanophores on the dorsal surface of the body as well as a lack of a vertical band of melanophores on the caudal peduncle distinguishing the larvae from those of "S. japonica". Modelling based on growth observations in the species suggests the female starts life smaller than the male but grows faster and is larger than the male within two years.cite journal | last = Hisaya | first = Imoto | coauthors = Yoshioka, Naoki; Kitajima, Chikara; Matsui, Seiichi | title = The age and growth of Blue Whiting, Sillago parvisquamis distributed in the coastal waters of North Eastern Kyushu | journal = Nippon Suisan Gakkaishi | volume = 63 | issue = 6 | pages = 892–898 | date = 1997 | id = ISSN 0021-5392 | accessdate =2007-12-22 ] The models put forward by Imoto "et al" in 1997 also suggest that the male reaches a maximum of 288 mm while the female reaches 332 mm, assuming their lifespan is long enough for these theoretical maxima to be reached.

Relationship to humans

Like many species of "Sillago" in the Asian region, "S. parvisquamis" is commonly taken in seines from beaches and estuaries but often suffers the same fate of other lesser known sillaginids in being confused with "S. sihama". This identification issue, as well as the fact that fisheries statistics are poor or non-existent in such countries means catch statistics are not available. In a 1984 review of the Japanese sillaginids, Sano and Mochizuchi described the species as being endangered due to habitat destruction and pollution, [cite journal | last = Sano | first = M | coauthors = Mochizuchi, K | title = A Revision of the Japanese Sillaginid Fishes | journal = Japanese Journal of Ichthyology 31 | volume = 31 | issue = 2 | pages = 136–149 | date = 1984 | id = ISSN 0021-5090 | accessdate = 2007-12-14 ] a statement echoed in a number of other papers since, although the IUCN does not recognise the species as being in danger. The discovery of the species in Korea in 1996 suggests its range may be greater than previously supposed, and thus less in danger of extinction than proposed by Sano and Mochizuchi. The flesh is held in high regard in Japan, but is still considered inferior to that of "S. japonica". For this reason, McKay proposed in 1992 that the species is possibly a candidate for aquaculture, although such a move has not yet been made.

References

External links

* [http://www.fishbase.org/Summary/SpeciesSummary.php?id=8534 Small-scale whiting at fishbase]
* [http://fishpix.kahaku.go.jp/fishimage-e/search?START=61&FAMILY=Sillaginidae&SPECIES=&LOCALITY=&FISH_Y=&FISH_M=&FISH_D=&PERSON=&PHOTO_ID=&JPN_FAMILY_OPT=1&FAMILY_OPT=0&JPN_NAME_OPT=1&SPECIES_OPT=1&LOCALITY_OPT=1&PERSON_OPT=1&PHOTO_ID_OPT=2 Colour photographs "S. parvisquamis"]