- Shadow trevally
Taxobox
name = Shadow trevally
image_width = 240px
regnum =Animal ia
phylum =Chordata
classis =Actinopterygii
ordo =Perciformes
subordo =Percoidei
superfamilia =Percoidea
familia =Carangidae
genus = "Carangoides "
species = "C. dinema"
binomial = "Carangoides dinema"
binomial_authority = Bleeker, 1851
range_
range_map_width = 240px
range_map_caption = Approximate range of the shadow trevally
synonyms =
*"Carangichthys dinema"
(Bleeker, 1851)
*"Caranx dinema"
(Bleeker, 1851)
*"Caranx deani"
Jordan & Seale, 1905The shadow trevally, "Carangoides dinema" (also known as the shadow kingfish, twothread trevally and Aldabra trevally) is a
species of inshore marinefish in the jack familyCarangidae . The species is patchily distributed throughout thetropical and subtropical waters of the Indian and westPacific Ocean s, fromSouth Africa in the west toJapan andSamoa in the east, reaching as far south asIndonesia andNew Caledonia . It is most easily distinguished from similar species by as series of dark rectangular blotches under the seconddorsal fin , giving a 'shadowed' appearance, from which itscommon name is derived. The shadow trevally is a reasonably large fish, growing to 85 cm in length and at least 2.6 kg in weight. It inhabits shallowcoastal waters includingreef s,bay s andestuaries , where it takes small fish and benthiccrustacean s as prey. Nothing is known of the speciesecology andreproductive biology . It is of little importance tofisheries , and is occasionally taken by bottom trawls and other artisanal fishing gear.Taxonomy and naming
The shadow trevally is classified within the
genus "Carangoides ", one of a number of groups of fish referred to as jacks and trevallies. "Carangoides" is further classified in the familyCarangidae , itself part of the suborderPercoidei and the orderPerciformes ; the perch-like fishes. [ITIS | ID = 641978 | taxon = "Carangoides dinema" | year = 2008 | date = 29 August]The
species was first scientifically described and named by the Dutchichthyologist Pieter Bleeker in 1851 based on a specimen collected from the waters offJakarta , located onJava inIndonesia , which was designated to be theholotype .cite journal | last = Lin | first = Pai-Lei | coauthors = Shao, Kwang-Tsao | title = A Review of the Carangid Fishes (Family Carangidae) From Taiwan with Descriptions of Four New Records | journal = Zoological Studies | volume = 38 | issue = 1 | pages = 33–68 | date = 1999 | url = http://cat.inist.fr/?aModele=afficheN&cpsidt=10055944 | accessdate = ] He named this new species "Carangoides dinema", with the specific name derived from the Latin "dis", meaning two and the Greek "nema", meaning thread, referring to the fin anatomy of the species. This classification in "Carangoides" is still currently considered to be correct, although other authors have at times transferred the species to "Caranx " and "Carangichthys". The species was independently renamed once byDavid Starr Jordan and Alvin Seale in 1908, who applied the name "Caranx deani" to the species. This later naming is considered invalid under theICZN nomenclature rules and is rendered ajunior synonym .FishBase species | genus = Carangoides | species = dinema | year = 2008 | month = September] The species is quite unique in the comparatively simple taxonomic history it has, with other related species often renamed and transferred between genera many times. The species is most commonly termed the 'shadow trevally' or 'shadow kingfish' in reference to a series of small dark blotches positioned on the upper side, underneath the second dorsal fin, giving the appearance of shadow from the fin itself. Other names used for the species include 'twothread trevally' and 'Aldabra trevally'.Description
The shadow trevally is similar in form to a number of other jacks in the family Carangidae, having an almost
ovate , strongly compressed body.cite book | last = Carpenter | first = Kent E. | coauthors = Volker H. Niem (eds.) | title = FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 4: Bony fishes part 2 (Mugilidae to Carangidae) | sher = FAO | date = 2001 | location = Rome | pages = 2684 | url = ftp://ftp.fao.org/docrep/fao/009/x2400e/x2400e52.pdf | isbn = 92-5-104587-9 |pages= p. 2694] It is fairly large fish, growing to a maximum known length of 85 cm [cite book | last = Kuiter | first = Rudie H. | coauthors = T. Tonozuka | title = Pictorial guide to Indonesian reef fishes. Part 1. Eels- Snappers, Muraenidae - Lutjanidae| publisher = Zoonetics | date = 2001 | location = Australia | pages = 302 | isbn = 979-98188-1-8 ] and a recorded weight of 2.6 kg. The dorsal profile is strongly convex, while the ventral profile is less so, even tending to be concave between the snout and theanal fin , while thenape is elevated and almost straight in profile. There are two separatedorsal fin s, the first consisting of 8 spines and second of a single spine and 17 to 19 soft rays. The lobe of the second dorsal fin is elongated, being greater than the head length. The anal fin is composed of two anteriorly detached spines followed by a single spine and 15 to 17 soft rays.cite book | last = Gloerfelt-Tarp | first = Thomas | coauthors = Patricia J. Kailola | title = Trawled Fishes of Southern Indonesia and Northeastern Australia | publisher = Australian Development Assistance Bureau | date = 1984 | location = Singapore | pages = 285 | isbn = 0 642 70001 X ] Thelateral line has a moderate arch anteriorly, with the junction of the curved and straight sections below the tenth or twelfth soft rays of the second dorsal fin. The curved section of the lateral line is slightly longer than the straight section, and contains 60 to 63 scales, while the straight part contains 0 to 6 scales followed by 23 to 30scutes . The breast is devoid of scales ventrally to behind thepelvic fin origin and up to thepectoral fin base, although in rare cases this is interrupted by a lateral band of scales. Bothjaw s contain bands of small teeth, with the bands becoming wider anteriorly, and the upper jaw also has an irregular outer series of moderately large teeth, with large specimens also showing this in the lower jaw. There are a total of 24 to 28gill raker s and 24vertebrae .In life, the shadow trevally is a blush green colour above, fading to a silvery white on the underside. It takes its common name from a series of small black-brown rectangular blotches which become larger posteriorly on its back between the bases of the second dorsal fin rays. There is also a dark brown diffuse blotch present on the operculum. The spinous dorsal fin is pale to dusky, while the second dorsal fin lobe is dusky with the ray tips yellowish. The anal fin has a distal margin which is whitish blue, the
caudal fin has a yellowish upper lobe and pale trailing edges and lower lobe tip. The pectoral fins arehyaline and the pelvic fins are whitish to dusky.Distribution and habitat
The shadow trevally is distributed patchily throughout the
tropical to subtropical waters of the Indian and westPacific Ocean s. The species westernmost limit is a section of theeast Africa n coast fromSouth Africa toTanzania . No records exist for the species further north untilIndia andSri Lanka . [cite book | last = Kapoor | first = D. | coauthors = R. Dayal and A.G. Ponniah (eds.) | title = Fish Biodiversity of India | publisher = National Bureau of Fish Genetic Resources | date = 2002 | location = Lucknow | pages = 228 | isbn = 81-901014-8-X ] In the Pacific, the species is known fromChina ,Korea ,South East Asia and theIndonesia n andPhilippines island chains. Its eastern most limit extends toTaiwan andJapan in the north and a number of small island groups includingTonga andSamoa in the south.The shadow trevally inhabits
coastal waters in depths generally less than 15 m. It is known to cruise in small schools along the shallow edge of steepreef drop-offs, and has also been recorded frombay s andestuaries . [cite journal | last = Kuo | first = S.R. | coauthors = K.T. Shao | title = Species composition of fish in the coastal zones of the Tsengwen estuary, with descriptions of five new records from Taiwan | journal = Zoological Studies | volume = 38 | issue = 4 | pages = 391-404 | date = 1999 | url = http://zoolstud.sinica.edu.tw/Journals/38.4/391-404.pdf | accessdate = 2008-09-21] The species has been recorded aroundshipwreck s, and one study showed it was one of the first fish to move in after a ship was scuttled. [cite journal | last = Wantiez | first = Laurent | coauthors = Pierre Thollotw | title = Colonisation of the F/V Caledonie Toho 2 Wreck by a Reef-Fish Assemblage Near Noumea (New Caledonia) | journal = Atoll Research Bulletin | volume = 485 | pages = 2-19 | date = 2000 | url = http://si-pddr.si.edu/dspace/bitstream/10088/4873/1/00485.pdf | accessdate =2008-09-21 ]Biology and fishery
The biology and
ecology of the shadow trevally is extremely poorly known. It is known to live either in small schools or individually, and is apredator y fish, taking small fish and benthiccrustacean s. Nothing is known of its movements orreproduction .The shadow trevally is of little importance to fisheries throughout its range, taken as
bycatch and generally not distinguished from other carangid species. It is often taken by bottomtrawl s and various kinds ofartisanal fishing gear.References
External links
* [http://www.fishbase.org/summary/SpeciesSummary.php?id=1925 Shadow trevally at Fishbase]
* [http://www.eol.org/taxa/17043863?category_id=1&expertise=expert Encyclopedia of Life page]
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