Octopus sinensis

The East Asian common octopus is adapted to a benthic life at the bottom of the sea. Octopus sinensis has long arms with many suckers used for catching prey, a [https://animals.howstuffworks.com/marine-life/octopus1.htm mantle] without a rigid skeleton, which allows them to inhabit and hunt in small spaces and crevices in the seabed, horizontal pupils, and versatile skin with ability to change colors and camouflage themselves with the sea floor.{{Citation|last1=Boletzky|first1=Sigurd von|title=Cephalopod Biology|date=2014|url=http://dx.doi.org/10.1007/978-94-017-8648-5_1|work=Cephalopod Culture|pages=3–16|place=Dordrecht|publisher=Springer Netherlands|isbn=978-94-017-8647-8|access-date=2022-02-14|last2=Villanueva|first2=Roger|doi=10.1007/978-94-017-8648-5_1|hdl=10261/327612|hdl-access=free}}{{Cite book|author=Hanlon, Roger T.|url=http://worldcat.org/oclc/1031978874|title=Cephalopod behaviour|date=9 March 2018|publisher=Cambridge University Press |isbn=978-0-511-84360-0|oclc=1031978874}}{{Cite book|last=scientifique.|first=Jereb, Patrizia. Éditeur scientifique. Roper, Clyde F. E. (1937-....). Éditeur scientifique. Norman, Mark D.. Éditeur scientifique. Finn, Julian K.. Éditeur|url=http://worldcat.org/oclc/1002064698|title=Cephalopods of the world : an annotated and illustrated catalogue of cephalopod species known to date.|date=15 November 2018 |publisher=Food & Agriculture Org. |isbn=978-92-5-107989-8|oclc=1002064698}} Compared to O. vulgaris, O. sinensis have a broader mantle and relatively shorter arms with about 80 fewer suckers. Mature O. sinensis males lack a standard sex organ, rather one of their arms (their third right arm) is specially adapted for reproduction.{{Cite web |last=Courage |first=Katherine Harmon |title=Odd Male Octopus Flaunts Two Unexpected Arm Phalluses |url=https://blogs.scientificamerican.com/octopus-chronicles/odd-male-octopus-flaunts-two-unexpected-arm-phalluses/ |access-date=2022-03-21 |website=Scientific American Blog Network |language=en}} This arm includes erectile tissue on its tip and has a channel for sperm packets. During copulation, O. sinensis males insert their third right arm into the female's mantle. The third right arm on mature O. sinensis males has far fewer suckers than that on O. vulgaris (120-140 vs. 150–190).{{Cite web |title=Japan's 'common octopus' not so common after all |url=https://www.sciencedaily.com/releases/2016/11/161102090510.htm |access-date=2022-03-21 |website=ScienceDaily |language=en}}

The East Asian common octopus goes through a several-week planktonic phase, in which they are floating in the open sea.{{Citation|title=Biology of the planktonic stages of benthic octopuses|date=2008-06-05|url=http://dx.doi.org/10.1201/9781420065756-6|work=Oceanography and Marine Biology|pages=111–208|publisher=CRC Press|doi=10.1201/9781420065756-6|isbn=9780429137259|access-date=2022-02-14}}{{Cite journal|last1=Villanueva|first1=Roger|last2=Vidal|first2=Erica A. G.|last3=Fernández-Álvarez|first3=Fernando Á.|last4=Nabhitabhata|first4=Jaruwat|date=2016-11-09|title=Early Mode of Life and Hatchling Size in Cephalopod Molluscs: Influence on the Species Distributional Ranges|journal=PLOS ONE|volume=11|issue=11|pages=e0165334|doi=10.1371/journal.pone.0165334|pmid=27829039|pmc=5102429 |bibcode=2016PLoSO..1165334V|issn=1932-6203|doi-access=free}} This occurs early in their development prior to their permanent benthic habitation, similar to many benthic octopus species.{{Cite journal|last1=ITAMI|first1=Kouzo|last2=IZAWA|first2=Yasuo|last3=MAEDA|first3=Saburo|last4=NAKAI|first4=Kozo|title=Notes on the Laboratory Culture of the Octopus Larvae|journal=Nippon Suisan Gakkaishi|date=1963|volume=29|issue=6|pages=514–520|doi=10.2331/suisan.29.514|issn=1349-998X|doi-access=free}}{{Citation|title=Diffuse Noxious Inhibitory Controls|url=http://dx.doi.org/10.1007/978-3-540-29805-2_1109|encyclopedia=Encyclopedia of Pain|year=2007|pages=605|place=Berlin, Heidelberg|publisher=Springer Berlin Heidelberg|doi=10.1007/978-3-540-29805-2_1109|isbn=978-3-540-43957-8|access-date=2022-02-14}} During their planktonic phase, the morphology of the East Asian common octopus is similar in morphology to the juvenile and adult life forms and is termed the paralarval stage after the octopus hatches.{{Cite book|last=E.|first=YOUNG, R.|url=http://worldcat.org/oclc/770420192|title='Larva', 'paralarva' and 'subadult' in cephalopod terminology|date=1988|oclc=770420192}} The paralarvae have certain characteristics that differ from the adult stage, which allow them to thrive in the planktonic phase, such as transparent musculature, circular pupils rather than horizontal ones, a proportionately larger mantle (2.1 mm in length) and shorter arms with fewer suckers (three to four on each arm), and a finely toothed beak. However, not much is known about the early life stages of the East Asian common octopus in their natural habitat due to their cryptic and allusive behavior.{{Cite journal|last1=Lishchenko|first1=F.|last2=Perales-Raya|first2=C.|last3=Barrett|first3=C.|last4=Oesterwind|first4=D.|last5=Power|first5=A.M.|last6=Larivain|first6=A.|last7=Laptikhovsky|first7=V.|last8=Karatza|first8=A.|last9=Badouvas|first9=N.|last10=Lishchenko|first10=A.|last11=Pierce|first11=G.J.|date=April 2021|title=A review of recent studies on the life history and ecology of European cephalopods with emphasis on species with the greatest commercial fishery and culture potential|url=http://dx.doi.org/10.1016/j.fishres.2020.105847|journal=Fisheries Research|volume=236|pages=105847|doi=10.1016/j.fishres.2020.105847|hdl=2164/16298|s2cid=233062343|issn=0165-7836|hdl-access=free}}{{Cite journal|last1=Dan|first1=Shigeki|last2=Shibasaki|first2=Shodai|last3=Takasugi|first3=Arata|last4=Takeshima|first4=Satoshi|last5=Yamazaki|first5=Hideki|last6=Ito|first6=Atsushi|last7=Hamasaki|first7=Katsuyuki|date=June 2021|title=Changes in behavioural patterns from swimming to clinging, shelter utilization and prey preference of East Asian common octopus Octopus sinensis during the settlement process under laboratory conditions|url=http://dx.doi.org/10.1016/j.jembe.2021.151537|journal=Journal of Experimental Marine Biology and Ecology|volume=539|pages=151537|doi=10.1016/j.jembe.2021.151537|s2cid=233538864|issn=0022-0981}} Recent studies suggest that transition from the planktonic stage to the benthic settlement is quite complex in O. sinensis and takes them a significant amount of time.{{Cite journal|last1=Dan|first1=Shigeki|last2=Takasugi|first2=Arata|last3=Shibasaki|first3=Shodai|last4=Oka|first4=Masakazu|last5=Hamasaki|first5=Katsuyuki|date=2020-06-17|title=Ontogenic change in the vertical swimming of East Asian common octopus Octopus sinensis paralarvae under different water flow conditions|url=http://dx.doi.org/10.1007/s10452-020-09777-7|journal=Aquatic Ecology|volume=54|issue=3|pages=795–812|doi=10.1007/s10452-020-09777-7|s2cid=219710545|issn=1386-2588}}

File:Octopus sinensis.jpg

Not until 2017 was O. sinensis named a separate species from O. vulgaris on the basis of molecular and morphological features. Both species are commercially important food sources in China and both are vulnerable to over fishing. Therefore, it is important to delineate the two species for sustainable and fisheries management.{{Cite journal|last1=Li|first1=Fenghui|last2=Liu|first2=Yuyan|last3=Qin|first3=Bo|last4=Bian|first4=Li|last5=Ge|first5=Jianlong|last6=Chang|first6=Qing|last7=Liu|first7=Hui|last8=Chen|first8=Siqing|date=2021-06-28|title=Sequence and phylogenetic analysis of the mitochondrial genome for the East Asian common octopus, Octopus sinensis (Octopodidae: Octopoda)|url=http://dx.doi.org/10.1080/23802359.2021.1944360|journal=Mitochondrial DNA Part B|volume=6|issue=8|pages=2120–2122|doi=10.1080/23802359.2021.1944360|pmid=34250235|pmc=8245087|issn=2380-2359}} In fact, some researchers claim that the misidentification of O. sinensis as O. vulgaris may be masking the decline of octopuses worldwide.{{Cite web |title=Misidentification may be masking decline of octopuses worldwide {{!}} SeafoodSource |url=https://www.seafoodsource.com/features/misidentification-may-be-masking-decline-of-octopus-worldwide |access-date=2022-03-21 |website=www.seafoodsource.com}} catches of octopus have been steadily declining across the globe. Due to its rapid rate of growth and its high commercial value, O. sinensis is of particular interest in aquacultural cultivation.{{Cite journal|last1=Dan|first1=Shigeki|last2=Iwasaki|first2=Hiraku|last3=Takasugi|first3=Arata|last4=Shibasaki|first4=Shodai|last5=Yamazaki|first5=Hideki|last6=Oka|first6=Masakazu|last7=Hamasaki|first7=Katsuyuki|date=2019-02-25|title=Effects of co-supply ratios of swimming crab Portunus trituberculatus zoeae and Artemia on survival and growth of East Asian common octopus Octopus sinensis paralarvae under an upwelling culture system|journal=Aquaculture Research|volume=50|issue=4|pages=1361–1370|doi=10.1111/are.14013|s2cid=92373762|issn=1355-557X|doi-access=free}} There have been several studies since the 1960s that have attempted to rear O. sinensis and O. vulgaris aquaculturally with little success.{{Cite journal|last1=Iglesias|first1=J.|last2=Otero|first2=J.J.|last3=Moxica|first3=C.|last4=Fuentes|first4=L.|last5=Sánchez|first5=F.J.|date=2004|title=The Completed Life Cycle of the Octopus (Octopus vulgaris, Cuvier) under Culture Conditions: Paralarval Rearing using Artemia and Zoeae, and First Data on Juvenile Growth up to 8 Months of Age|url=http://dx.doi.org/10.1023/b:aqui.0000042142.88449.bc|journal=Aquaculture International|volume=12|issue=4/5|pages=481–487|doi=10.1023/b:aqui.0000042142.88449.bc|s2cid=39160015|issn=0967-6120}}{{Cite journal|last1=Okumura|first1=Shigenobu|last2=Kurihara|first2=Ayako|last3=Iwamoto|first3=Akio|last4=Takeuchi|first4=Toshio|date=February 2005|title=Improved survival and growth in Octopus vulgaris paralarvae by feeding large type Artemia and Pacific sandeel, Ammodytes personatus|url=http://dx.doi.org/10.1016/j.aquaculture.2004.11.044|journal=Aquaculture|volume=244|issue=1–4|pages=147–157|doi=10.1016/j.aquaculture.2004.11.044|issn=0044-8486}} Current studies are focused on developing more accurate gene expression profiles to better understand the metabolic process and nutritional requirements of O. sinensis during its paralarval stage for aquacultural production of O. sinensis.{{Cite journal |last1=Li |first1=Fenghui |last2=Bian |first2=Li |last3=Ge |first3=Jianlong |last4=Han |first4=Fengming |last5=Liu |first5=Zhihong |last6=Li |first6=Xuming |last7=Liu |first7=Yongsheng |last8=Lin |first8=Zhishu |last9=Shi |first9=Huilai |last10=Liu |first10=Changlin |last11=Chang |first11=Qing |date=2020-08-20 |title=Chromosome-level genome assembly of the East Asian common octopus (Octopus sinensis) using PacBio sequencing and Hi-C technology |url=http://dx.doi.org/10.1111/1755-0998.13216 |journal=Molecular Ecology Resources |volume=20 |issue=6 |pages=1572–1582 |doi=10.1111/1755-0998.13216 |pmid=32603549 |s2cid=220288998 |issn=1755-098X}}

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Category:Octopodidae

Category:Molluscs described in 1841