Acanthopagrus schlegelii
{{Short description|Species of fish}}
{{speciesbox
| image = クロダイ.jpg
| status = LC
| status_system = IUCN3.1
| taxon = Acanthopagrus schlegelii
| authority = (Bleeker, 1854)
| synonyms = {{Specieslist
| Chrysophrys schlegelii | Bleeker, 1854
| Acanthopagrus schlegelii schlegelii | (Bleeker, 1854)
| Pagrus macrocephalus | Basilewsky, 1855
| Mylio macrocephalus | (Basilewsky, 1855)
| Sparus macrocephalus | (Basilewsky, 1855)
| Sparus swinhonis czerskii | Berg, 1914
| Acanthopagrus schlegelii czerskii | (Berg, 1914)
| Acanthopagrus swinhonis czerskii | (Berg, 1914)
| Sparus macrocephalus czerskii | Berg, 1914
}}
| synonyms_ref = {{FishBase|Acanthopagrus|schlegelii|month=October|year=2023}}
}}
Acanthopagrus schlegelii, the blackhead seabream, black porgy or black seabream, is a species of marine ray-finned fish belonging to the family Sparidae, the seabreams and porgies. This species is found in the Western Pacific Ocean. The blackhead seabream is an important species in commercial fisheries, particularly in Vietnam.
Taxonomy
Acanthopagrus schlegelii was first formally described as Chrysophrys schlegelii in 1854 by the Dutch physician, herpetologist and ichthyologist Pieter Bleeker with its type locality given as Nagasaki.{{Cof genus|genus=Acanthopagrus|access-date=24 December 2023}} Some workers have suggested that there are two species within this taxon, A. schlegelii and A. czerskii,{{cite journal |author=Dolganov, V. |author2=Kharin, V. |author3=Zemnukhov, V. |name-list-style=& |year=2008 |title=New records of a rare species of spariform fish Acanthopagrus schlegelii (Bleeker, 1854) (Osteichthyes: Sparidae) from Russian waters of the sea of Japan, with notes on the taxonomy of the genus Acanthopagrus Peters, 1855 |journal=Russian Journal of Marine Biology |volume=34 |issue=4 |pages=220–223 |doi=10.1134/S1063074008040020|bibcode=2008RuJMB..34..220D }} while others treat these as subspecies within the same species.{{cite web |url=https://etyfish.org/spariformes/ |title=Order SPARIFORMES: Families LETHRINIDAE, NEMIPTERIDAE and SPARIDAE |work=The ETYFish Project Fish Name Etymology Database |access-date=24 December 2023 |date=17 October 2022 |publisher=Christopher Scharpf |archive-date=30 October 2023 |archive-url=https://web.archive.org/web/20231030165034/https://etyfish.org/spariformes/ |url-status=dead }} Some authorities classify the genus Acanthopagrus in the subfamily Sparinae,{{cite journal |author= Parenti, P. |year=2019 |title=An annotated checklist of the fishes of the family Sparidae |journal=FishTaxa |volume=4 |issue=2 |pages=47–98 |url= https://fishtaxa.com/menuscript/index.php/ft/article/view/49/52}} but the 5th edition of Fishes of the World does not recognise subfamilies within the Sparidae.{{cite book |author1=Nelson, J.S. |author1-link=Joseph S. Nelson |author2=Grande, T.C. |author3=Wilson, M.V.H. |year=2016 |title=Fishes of the World |edition=5th |publisher=John Wiley & Sons |place=Hoboken, NJ |pages=502–506 |isbn=978-1-118-34233-6 |lccn=2015037522 |oclc=951899884 |ol=25909650M |doi=10.1002/9781119174844}}
Etymology
Acanthopagrus schlegelii has a specific name that honours the German ornithologist and herpetologist Hermann Schlegel who co-wrote Fauna Japonica with Coenraad Jacob Temminck, a book Bleeker often cited. The subspecies A. s. czerskii honours the ornithologists Alexander Ivanovich Czerski, the son of Jan Czerski, a celebrated Polish geologist, naturalist and explorer, who collected the type specimen.
Description
Acanthopagrus schlegelii has its dorsal fin supported by 11 or 12 spines and 11 soft rays while the anal fin contains 3 spines and 8 soft rays. This species differs from the other species in the gneus Acanthopagrus by having pale dorsal, caudal, anal, and pelvic fins being light colour.{{cite journal |author1=Iwatsuki, Y. |author2=M. Kume |author3=T. Yoshino |name-list-style=and |year=2010 |title=A new species, Acanthopagrus pacificus from the western Pacific (Pisces, Sparidae) |journal=Bulletin of the National Museum of Nature and Science (Ser. A) |volume=36 |issue=4 |pages=115–130 |url=https://www.kahaku.go.jp/research/publication/zoology/download/36_4/BNMNS_A360404.pdf}} The overall colour is black or grey, silvery on the belly, with indistinct vertical stripes along the body and a round spot on the upper margin of the operculum.{{cite web |url=https://orbis-pictus.jp/en/article/kurodai.php|title=Jaoanese black porgy|access-date=24 December 2023 |publisher=Orbis Pictus}} The maximum published standard length for this species is {{cvt|50|cm}}.
Distribution and habitat
Acanthopagrus schlegelii is found in the northwestern Pacific Ocean where it is found in the Sea Of Japan, the eastern coast Japan from central Honshu south, the Yellow Sea and the East and South China Seas. This species is found in sheltered bays, on shallow rocky reefs and in brackish waters down as deep as {{cvt|50|m}}.
Biology
Acanthopagrus schlegelii is a predatory species feeding on molluscs and polychaetes. It is a protandrous hermaphrodite that spawns during the spring and summer. They spawning behaviour reaches its daily peaks just before sunset and the reduction in light levels appears to stimulate the fish to spawn.{{Cite journal |author=Kentaro Kawai |author2=Hiroki Fujita |author3=Diego Deville |author4=Tetsuya Umino |year=2022 |title=Spawning time of black sea bream Acanthopagrus schlegelii, related to underwater photoperiodism in oyster farms |journal=Journal of Fish Biology |volume=101 |issue=5 |pages=1142–1149 |doi=10.1111/jfb.15179|pmid=35880803 |bibcode=2022JFBio.101.1142K }} Males have a maximum age of 20 years and females 28 years and males are more numerous in the lower size classes.{{cite journal |author=Hiroshi Yamashita |author2=Satoshi Katayama |author3=Tomoyuki Koyima |name-list-style=and |year=2015 |title=Age and Growth of Black Sea Bream Acanthopagrus schlegelii (Bleeker 1854) in Tokyo Bay |journal=Asian Fisheries Science |volume=28 |pages=47–59 |doi=10.33997/j.afs.2015/28.2.001|doi-broken-date=1 November 2024 }}
Fisheries and aquaculture
Acanthopagrus schlegelii is an important food fish in Vietnam. This species is an important fish in aquaculture in Korea, China and Japan. China produced {{cvt|123,000|t}} in 2022.{{cite journal |author=Xuejiao Li |author2=Yuedong Shen |author3=Yangguang Bao |author4=Zhaoxun Wu |author5=Bingqian Yang |author6=Lefei Jiao |author7=Chundan Zhang |author8=Douglas R. Tocher |author9=Qicun Zhou |author10=Min Jin |year=2022|title=Physiological responses and adaptive strategies to acute low-salinity environmental stress of the euryhaline marine fish black seabream (Acanthopagrus schlegelii) |journal=Aquaculture |volume=554 |page=738117 |doi=10.1016/j.aquaculture.2022.738117|bibcode=2022Aquac.55438117L }}
File:NDL-DC 1306184-Utagawa Hiroshige-広重魚尽 黒鯛・小鯛・山椒-crd.jpg|Japanese print by Hiroshige, 1830s. Black seabream (kurodai) is shown on the left
File:魚太郎半田店 20241027 1818.jpg|Kurodai as sushi
File:黒鯛（氷見きときと寿し氷見本店）.jpg