{{Short description|Species of ray-finned fish}} {{Speciesbox | image = Duskyshoulder trevally.png | status = LC | status_system = IUCN3.1 | status_ref = <ref name = iucn>{{cite iucn | author1 = Smith-Vaniz, W.F. | author2 = Williams, I. | name-list-style = amp | year = 2016 | title = ''Carangoides humerosus'' |errata=2017 | volume = 2016 | article-number = e.T20429793A115374804 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T20429793A67871545.en }}</ref> | taxon = Carangichthys humerosus | authority = ([[Allan Riverstone McCulloch|McCulloch]], 1915) | range_map = Carangoides humerosus distribution.png | range_map_caption = Known range of the duskyshoulder trevally | synonyms = *''Carangoides humerosus''<br /><small>(McCulloch, 1915)</small> *''Caranx humerosus''<br /><small>McCulloch, 1915</small> }}
The '''duskyshoulder trevally''' ('''''Carangichthys humerosus''''') or '''epaulet trevally''', is a [[species]] of small inshore [[marine fish]] in the [[Family (taxonomy)|family]] [[Carangidae]]. It is distributed through the eastern [[Indian Ocean|Indian]] and western [[Pacific Ocean]]s, ranging from eastern [[India]] to northern [[Australia]] and [[Taiwan]]. It is relatively small by carangid standards, reaching only 27 cm maximum length, and can be distinguished by the large, black blotches on its shoulders. The duskyshoulder trevally is an [[inshore]] fish living in waters less than 50 m deep, over sandy substrates in [[bay]]s and on the [[continental shelf]]. It is a predatory fish, taking demersal fishes, [[crustacean]]s, and [[cephalopod]]s, with nothing known of its reproductive habits. It is of little value to [[fisheries]], often taken as bycatch in [[prawn]] trawling operations.
==Taxonomy and naming== The duskyshoulder trevally is classified within the genus ''[[Carangichthys]]''.<ref name="ECoF species">{{Catalog of Fishes |genus=Carangichthys |list=species |date=12 February 2026}}</ref> ''Carangichthys'' falls into the jack and horse mackerel family [[Carangidae]], and Carangidae is part of the [[Order (biology)|order]] [[Carangiformes]].<ref name = Nelson5>{{cite book |title=Fishes of the World |edition=5th |author1=J. S. Nelson |author2=T. C. Grande |author3=M. V. H. Wilson |year=2016 |pages=380–387 |publisher=Wiley |isbn=978-1-118-34233-6 |url=https://sites.google.com/site/fotw5th/ |access-date=2019-11-24 |archive-date=2019-04-08 |archive-url=https://web.archive.org/web/20190408194051/https://sites.google.com/site/fotw5th/ }}</ref>
The species was first [[scientific classification|scientifically described]] by the Australian [[ichthyologist]] [[Allan Riverstone McCulloch]] in 1915 based on the [[holotype]] specimen taken from [[Bustard Head]] in [[Queensland]], Australia.<ref name = "Zoocat">{{cite book | last = Hosese | first = D.F. |author2=Bray, D.J. |author3=Paxton, J.R. |author4=Alen, G.R. | title = Zoological Catalogue of Australia Vol. 35 (2) Fishes | publisher = CSIRO | year = 2007 | location = Sydney | page = 1150 | isbn =978-0-643-09334-8 }}</ref> He named the species ''Caranx humerosus'', with the [[specific name (zoology)|specific epithet]] literally meaning "having shoulders" in reference to the species prominent dark shoulder colouring. The species was later transferred to the genus ''[[Carangoides]]'',<ref name = "Zoocat"/> but [[Eschmeyer's Catalog of Fishes]] and [[FishBase]] now include it in ''Carangichthys''.<ref name="ECoF species" /><ref name = "fishbase">{{FishBase | genus = Carangichthys | species = humerosus | year = 2026 | month = February}}</ref> The species has not been redescribed under another name, which is rare amongst the Carangidae. The [[common name]] 'duskyshoulder trevally' refers to the prominent shoulder markers, as does the name '[[epaulet]] trevally'.<ref name = "fishbase" />
==Description== [[File:Carangoides humerosus.jpg|thumb|left|''Carangoides humerosus'' by [[Allan Riverstone McCulloch|McCulloch]]]]
The duskyshoulder trevally is a small fish reaching only 27 cm in length.<ref name = "Lin1999">{{cite journal | last = Lin | first = Pai-Lei | author2 = 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 | year = 1999 | url = http://cat.inist.fr/?aModele=afficheN&cpsidt=10055944 | access-date = 2008-10-27 | archive-date = 2012-02-29 | archive-url = https://web.archive.org/web/20120229173915/http://cat.inist.fr/?aModele=afficheN&cpsidt=10055944 }}</ref> The species is similar to other jacks in its overall body profile, having a [[Compression (zoology)|compressed]] [[wikt:ovate|ovate]] to [[wikt:oblong|oblong]] shape, with the [[anatomical terms of location#Dorsal and ventral|dorsal]] profile more convex than the ventral profile.<ref name = "Barrier">{{cite book | last = Randall | first = John Ernest |author2=Roger C. Steene |author3=Gerald R. Allen | title = Fishes of the Great Barrier Reef and Coral Sea | publisher = University of Hawaii Press | year = 1997 | page = 161 | isbn = 0-8248-1895-4 }}</ref> The head profile is gently sloping and slightly convex, with large males having a distinct bulge that is absent in females and juveniles of both sexes. Both of the [[jaw]]s contain anteriorly widening bands of small [[Ichthyology terms#V|villiform]] teeth, with older individuals also having a number of larger outer teeth.<ref name = "FAO">{{cite book |editor-last=Carpenter |editor-first=Kent E. |editor2=Volker H. Niem | 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) | publisher = FAO | year = 2001 | location = Rome |page= 2694 | url = ftp://ftp.fao.org/docrep/fao/009/x2400e/x2400e52.pdf | isbn = 92-5-104587-9}}</ref> Two separate [[dorsal fin]]s occur, the first consisting of eight [[Fish anatomy#Spines and rays|spines]] and the second of one spine and 20 to 22 [[Fish anatomy#Spines and rays|soft rays]]. The [[anal fin]] has two detached [[Anatomical terms of location#Anterior and posterior|anterior]] spines, followed by one spine and 17 to 19 soft rays.<ref name = "Lin1999"/> The lobe of the soft dorsal fin is [[Ichthyology terms#F|falcate]], being about the same length as the head. The pelvic fin consists of one spine and 18 or 19 soft rays. The lateral line is moderately curved anteriorly, with the curve having 62 to 72 scales present on it, while the straight section contains three to eight scales and 24 to 32 scutes.<ref name = "Lin1999"/> The breast of the duskyshoulder trevally is scaleless, extending up to behind the [[pelvic fin]] origin and laterally to the pectoral fin base. It has six to 10 [[gill raker]]s on the first arch and 16 to 20 on the second arch, and the species has 24 [[vertebrae]].<ref name = "FAO"/>
The duskyshoulder trevally is a dusky green colour above, fading to silver below, with adults and juveniles often having five or six dark broad crossbars running vertically down their bodies.<ref name = "Gunn">{{cite journal | doi = 10.3853/j.0812-7387.12.1990.92 | last = Gunn | first = John S. | title = A revision of selected genera of the family Carangidae (Pisces) from Australian waters | journal = Records of the Australian Museum Supplement| volume = 12 | pages =1–78 | year = 1990 | url = https://australianmuseum.net.au/Uploads/Journals/17723/92.pdf }}<!--| access-date =2007-11-01 --></ref> A large black spot is usually present on the shoulder, with smaller dark spots on the [[operculum (fish)|operculum]] and [[pectoral fin]] axil. The soft dorsal, anal, and [[caudal fin]]s are dusky, with the spinous dorsal fin black. The pectoral and pelvic fins are [[hyaline]] to white in colour.<ref name = "Gunn"/>
==Distribution and habitat== The duskyshoulder trevally inhabits the tropical and subtropical regions of the eastern [[Indian Ocean]] and western [[Pacific Ocean]], recorded only from the coastlines of [[India]], [[Indonesia]], [[Papua New Guinea]], northern [[Australia]],<ref name = "fishbase"/> and possibly [[Taiwan]].<ref name = "Lin1999"/> The species probably inhabits offshore areas of more islands in the region, but due to inadequate sampling, has not been recorded.
The species lives in waters shallower than 50 m,<ref name = "Gunn"/> generally inhabiting the [[sand]]y [[substrate (marine biology)|substrates]] and [[reef]]s of the [[continental shelf]], also venturing into [[bay]]s and inhabiting [[beach]]es and [[mangrove]]-lined creeks.<ref>{{cite journal | last = Brewer | first = D.T. |author2=S.J.M. Blaber |author3=J.P. Salini |author4=M.J. Farmer | title = Feeding Ecology of Predatory Fishes from Groote Eylandt in the Gulf of Carpentaria, Australia, with Special Reference to Predation on Penaeid Prawns | journal = [[Estuarine, Coastal and Shelf Science]] | volume = 40 | issue = 5 | pages = 577–600 | year = 1995 | doi = 10.1006/ecss.1995.0039 | bibcode = 1995ECSS...40..577B }}<!--| access-date = 2008-10-20 --></ref>
==Biology and fishery== The duskyshoulder trevally is poorly studied in most aspects of its biology with the exception of its diet. It is a [[benthic]] [[predator]], with studies in the [[Gulf of Carpentaria]] indicating it preys mostly on various species of small [[teleost]] fishes and [[crustacean]]s, with particular preference for [[brachyura]]ns.<ref name = "prawn">{{cite journal | last = Brewer | first = D.T. |author2=S.J.M. Blaber |author3=J.P. Salini | title = Predation on penaeid prawns by fishes in Albatross Bay, Gulf of Carpentaria | journal = Marine Biology | volume = 109 | issue = 2 | pages = 231–240 | year = 1991 | doi = 10.1007/BF01319391 | bibcode = 1991MarBi.109..231B }}<!--| access-date = 2008-08-05--></ref> Other less commonly taken prey include [[penaeid]] prawns, other crustaceans, [[mollusc]]s, and [[cephalopod]]s.<ref name = "Gunn"/><ref name = "prawn"/> Nothing is known of the movements or reproduction in the species.
The duskyshoulder trevally is of little importance to either commercial [[fisheries]] or [[angling|angler]]s,<ref name = "FAO"/> but is commonly taken as bycatch in other [[trawl]] fisheries, especially the northern Australian prawn fishery.<ref>{{cite journal | last = Stobutzk | first = Ilona C. |author2=Margaret J. Miller |author3=Peter Jones |author4=John P. Salini | title = Bycatch diversity and variation in a tropical Australian penaeid fishery; the implications for monitoring | journal = Fisheries Research | volume = 53 | issue = 3 | pages = 283–301 | year = 2001 | doi = 10.1016/S0165-7836(00)00273-3 | bibcode = 2001FishR..53..283S }}<!--| access-date = 2008-10-20 --></ref> It is mostly discarded when taken, rarely sold at market.<ref>{{cite journal | last = Errity | first = C.M. | title = A description of the NT finfish fishery | journal = Fishery Report | volume = 68 | pages = 1–28 | publisher = Northern Territory Department of Business, Industry and Resource Development | year = 2003 | url = http://www.nt.gov.au/dpifm/Content/File/p/Fish_Rep/FR68.pdf | access-date = 2008-10-20 | archive-url = https://web.archive.org/web/20080818175846/http://www.nt.gov.au/dpifm/Content/File/p/Fish_Rep/FR68.pdf | archive-date = 2008-08-18 }}</ref>
==References== {{Reflist|2}}
{{Taxonbar|from=Q2049120}}
[[Category:Caranginae]] [[Category:Fish of the Indian Ocean]] [[Category:Fish of the Pacific Ocean]] [[Category:Fish described in 1915|duskyshoulder trevally]]