Long-sleeved octopus

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Long-sleeved octopus
Long-sleeved octopus in the aquarium

Long-sleeved octopus in the aquarium

Systematics
Subclass : Octopus (coleoidea)
Superordinate : Eight-armed squid (Vampyropoda)
Order : Octopus (octopoda)
Family : Real octopus (Octopodidae)
Genre : Octopus ( Octopus )
Type : Long-sleeved octopus
Scientific name
Octopus minor
( Sasaki , 1920)

The long-arm octopus ( Octopus minor ) is a small to medium-sized cephalopod from the order of the octopus . It lives in the benthos of the East Asian coastal waters of the Pacific and is of great importance for the fishing industry in Japan, Korea and China .

features

Long-sleeved octopus, habitus

The long-arm octopus is a small to medium-sized, elongated octopus , with a coat length of up to 80 millimeters and a total length of up to 700 millimeters. The vivid color is reddish brown with light yellow spots on the dorsal surface, but without eye spots. The skin is soft and smooth, but the animals can give it an irregular warty structure.

The tentacles are thin and four to five times as long as the pallium . The two dorsal pairs of tentacles are significantly longer and stronger than the ventral ones, with the arm formula 1> 2> 3 = 4. Long-arm octopuses are not capable of autotomy . The skins between the tentacles are only weakly developed and extend over a maximum of a tenth of the arm length, whereby they are more developed on the dorsal arms than on the ventral ones. They have no water pockets. Each tentacle is equipped with two rows of suction cups, with large long-arm octopuses there are around 180 suction cups on each normally formed tentacle. In adult males, the eighth or ninth pair of suction cups are greatly enlarged, especially on the dorsal tentacles. Their diameter can reach one sixth the length of the pallium. The right third tentacle is transformed into a hectocotylus and is only about half as long as its left counterpart, with only forty to sixty suction cups. The ligula is large, about 18 to 23 percent the length of the hectocotylus. It is shaped like a spoon, with rolled edges and ten to fourteen transverse grooves on the bottom. The calamus is pointed and small, less than one-fifth the length of the ligula. The spermatophores are about 42 millimeters long and very thick throughout, the spermatic cord has about 40 turns. The eggs are medium-sized at eight millimeters.

There are ten to twelve lamellae on each gill lobe . The Mullerian organ located in the funnel organ is double V-shaped, its outer arms are slightly shorter than the middle ones. The nine-part radula has seven longitudinal rows of teeth and marginal plates and two, rarely three lateral folds on the basal tooth. An ink bag and anal flaps are provided.

distribution

The type locality of the long-arm octopus is the Suruga Bay on the Pacific coast of the island of Honshū in Japan , west of the Izu Peninsula ( 34 ° 40 ′ 45 ″  N , 138 ° 18 ′ 30 ″  E ). The species was common there around 1929. The distribution area is the coastal waters from the Russian island Sakhalin in the north over Japan and Korea and along the Chinese coast, possibly to Hong Kong .

Way of life

Long-arm octopus and California two-point octopus ( Octopus bimaculoides ) in comparison, diagram of a living tube in the mudflats

habitat

The long-arm octopus colonizes the benthos of the coastal regions to a depth of 200 meters. It prefers soft sediments in which it likes to dig itself. Long-arm octopuses are nocturnal in captivity. When mating, the male lies on the female's back and inserts his hemicotylus into the mantle, where the spermatophore is shed near the fallopian tube. Most males die after mating, they only live up to 250 days in captivity. The females can keep the spermatophores for at least two weeks until they lay eggs. To lay their eggs, the females seek shelter in which, depending on their body weight, they attach nine to 125 eggs close to each other on the wall. The eggplant-shaped eggs are 13 to 20 millimeters long with a diameter of 4 to 6 millimeters. The laying of eggs can take a week. The females guard the clutch and ensure that the brood cavity is kept clean and that fresh water is regularly supplied. They die after the hatchlings and can reach an age of up to 346 days when kept.

Hazard and protection

The IUCN ( International Union for Conservation of Nature ; completely International Union for Conservation of Nature and Natural Resources ; German International Union for the Preservation of Nature ) does not carry out a risk assessment for the long-arm octopus due to insufficient data. However, the organization points to declining stocks. In Korea, fishing guidelines have been introduced for long-arm octopus and other types of fish and seafood in order to conserve stocks. Some of the long-arm octopus used in Chinese aquaculture are released into the sea to support the declining stocks.

Parasites

The parasitic fauna of the cephalopods has only been poorly researched, only extensive studies are available for the common squid ( Sepia officinalis ) and the common octopus ( Octopus vulgaris ). Along with Amphioctopus fangsiao, the long-arm octopus is one of only two known species that are parasitized by the copepod Octopicola huanghaiensis, described in 2018 from the Yellow Sea off Qingdao . Since only nine Lamgarm octopuses were examined, two of which each harbored one of the parasites, no statement can be made about the prevalence .

Systematics

The first description comes from Madoka Sasaki from 1920, Sasaki described the species as Polypus macropus var. Minor . Among the synonyms of the species include Polypus variabilis var. Typicus Sasaki, 1929 and Octopus variabilis (Sasaki, 1929). The subspecies O. minor minor , O. minor pardalis and O. minor variabilis described by Madoka Sasaki are no longer supported today. The holotype (USNM 332963, formerly USNM 332963b) and a paratype (USNM 577540) are in the National Museum of Natural History of the Smithsonian Institution in Washington, DC The syntypes of several synonyms of the species described later are in the Zoological Collection of the University of Tokyo .

The taxon known as Octopus minor is believed to be a species complex that includes several cryptic species. Belonging to the genus Octopus is doubted for Octopus minor and numerous other species. A revision of the genus is in progress and it is likely that Octopus will be split into several genera.

Economical meaning

Long-sleeved octopuses in a fish market in South Korea

The long-arm octopus was already of great economic importance in its area of ​​distribution in the early 20th century.

Catch

The Food and Agriculture Organization of the United Nations (FAO) does not classify octopus catches by species. In 2010, the FAO recorded 217 506 tons of different species of octopus in Asia. In addition, there are a large number of statistically unrecorded catches. In China alone, more than 10,000 tons of long-arm octopus were caught, most of which were exported to Japan and Korea. Adult long-arm octopus are caught with bottom trawls during the fishing season from May to June. Besides be drift nets , and on the coasts of fixed nets used and fall, in Korea, the vast amount is caught in traps. In the Chinese Wadden Sea they are dug up directly from their mud caves by fishermen. In spring and autumn, young octopuses are also caught in this way for aquaculture. Small to medium amounts of them are brought in as bycatch in trawling . The catch has fallen sharply since the turn of the millennium. In Korea, annual catches fell from a peak of 15,000 tons in 1993 to less than half in 2006.

In connection with the keeping of long-arm octopuses in aquacultures, there was a need for clutches of wild animals with the females caring for the brood. Brood tubes developed for this purpose are buried in the tidal flats during the main breeding season in mid-May and collected again at the end of July. The brood tubes covered with clutches and the females are transferred to tanks for further rearing.

Aquaculture

The demand for octopus and declining populations prompted research into cephalopod aquaculture, including the long-arm octopus, in the early 21st century. The efforts provided extensive insight into the species' reproductive cycle.

After the capture and acclimatization of reproductive animals, they mate and lay their eggs on an artificial substrate. The clutches are cared for by the mothers until embryonic development is complete after 72 to 89 days at a temperature of 21 to 25 ° C and a salinity of 28 to 31 PSU. In newly hatched octopuses, the length of the pallium ranges from 8.5 to 11.5 millimeters and the total length from 25 to 31 millimeters. The benthic octopuses immediately seek to hatch to the bottom of their tank, where ceramic pots with a diameter of 8 to 12 millimeters and PVC tubes with a diameter of 10 millimeters are offered as shelter. They are first with water fleas , copepods and nauplii of the brine shrimp fed. At the age of ten days, young Asiatic beach crabs with a carapace of less than four millimeters wide are added. With this feeding, 75 percent of the octopuses survive the first month.

Then the feeding is switched to young crabs , shrimp and mussels . After six to seven months in tanks, the animals, which weigh around 100 grams, are brought to outdoor ponds for further rearing, or released into the sea to increase their populations. If kept further, an average weight of 123 grams for male and 197 grams for female octopuses is achieved after 250 days.

Food

Movement of the Sannakji on a plate

Long-sleeved octopuses are a popular food in East Asian kitchens, fresh or dried. They are considered rich in proteins and omega-3 fatty acids, as well as minerals and vitamins. A study of long-arm octopus from the west coast of Korea for the content of the heavy metals cadmium , copper and zinc showed values ​​that were significantly lower for all three metals than the values ​​published for common octopus ( Octopus vulgaris ) from the Mediterranean . Cadmium and zinc are mainly concentrated in the internal organs, while the copper bound in the blood of octopuses is mainly to be found in the coat. The measured concentrations do not pose a health risk if octopuses are regularly consumed in normal quantities.

In Korean cuisine , the long-sleeved octopus is valued as a food that is said to give strength and endurance. By sannakji which consists of actually or apparently alive ate octopus a Korean court, the long-sleeved octopus (in South Korea is nakji ) became known far beyond its geographical borders. It is also the main ingredient in several other dishes:

  • Long-sleeved octopuses in Korean cuisine

  • Nakji-bokkeum

  • Nakji-tang

  • Nakji-jeot (in the foreground)

  • Baksok – nakji

Model organism

Cephalopods are of great interest in evolutionary research and other disciplines because of their outstanding individual cognitive abilities, their memory abilities and the willingness of the species to adapt their behavior and morphology to different living conditions compared to other invertebrates . To support this research, the full genome of the long-arm octopus was sequenced . It is 5,090,349,614 base pairs in size and contains 30,010 protein-coding genes . The mitochondrial DNA was sequenced in 2012, it contains 15,974 base pairs and 13 genes.

Two peptides have been isolated from the brains of long-arm octopuses that play a role in regulating the activity of the systemic heart. The controls of the cephalopods' blood circulation are the subject of current research, which focuses on common octopuses.

Web links

Commons : Long Sleeve Octopus  - Collection of Images, Videos, and Audio Files

literature

  • Rubin Cheng et al .: Determination of the complete mitochondrial DNA sequence of Octopus minor . In: Molecular Biology Reports . tape 39 , 2012, p. 3461-3470 , doi : 10.1007 / s11033-011-1118-2 .
  • Xin Du, Chao Dong, Shi-Chun Sun: Octopicola huanghaiensis n. Sp. (Copepoda: Cyclopoida: Octopicolidae), a new parasitic copepod of the octopuses Amphioctopus fangsiao (d'Orbigny) and Octopus minor (Sasaki) (Octopoda: Octopodidae) in the Yellow Sea . In: Systematic Parasitology . tape 95 , no. 8-9 , 2018, pp. 905-912 , doi : 10.1007 / s11230-018-9819-8 .
  • Ian G. Gleadall: A note on the Cephalopoda type specimens in the Zoology Department of Tokyo University Museum . In: Interdisciplinary Information Sciences . tape 69 , no. 4 , 2003, p. 375-380 , doi : 10.1093 / mollus / 69.4.375 .
  • Ian G. Gleadall, M. Alejandro Salcedo-Vargas: Catalog of the Cephalopoda Specimens in the Zoology Department of Tokyo University Museum . In: Interdisciplinary Information Sciences . tape 10 , no. 2 , 2004, p. 113–142 , doi : 10.4036 / iis.2004.113 ( jst.go.jp [PDF; 213 kB ]).
  • FG Hochberg: The parasites of Cephalopods: A review . In: Memoirs of the National Museum of Victoria . tape 44 , 1983, pp. 108-145 ( digitized versionhttp: //vorlage_digitalisat.test/1%3D~GB%3D~IA%3DMemoirsNational44Nati~MDZ%3D%0A~SZ%3D~doppelseiten%3D~LT%3D~PUR%3D ).
  • Eiko Iwakoshi, Miki Hisada, Hiroyuki Minakata: Cardioactive peptides isolated from the brain of a Japanese octopus, Octopus minor . In: Peptides . tape 21 , no. 5 , 2000, pp. 623-630 , doi : 10.1016 / S0196-9781 (00) 00201-1 .
  • Bo-mi Kim et al .: The genome of common long-arm octopus Octopus minor . In: GigaScience . tape 7 , no. 11 , 2018, article giy119 , doi : 10.1093 / gigascience / giy119 .
  • Do Hoon Kim, Heui Chun An, Kyoung Hoon Lee, Jin-Wook Hwang: Optimal economic fishing efforts in Korean common octopus Octopus minor trap fishery . In: Fisheries Science . tape 74 , no. 6 , 2008, p. 1215-1221 , doi : 10.1111 / j.1444-2906.2008.01645.x .
  • Hyo Jin Lee, Gi Beum Kim: Concentration of Heavy Metals in Octopus minor in Seosan, Chungnam and Food Safety Assessment . In: Korean Journal of Fisheries and Aquatic Sciences . tape 43 , no. 3 , 2010, p. 270–276 , doi : 10.5657 / kfas.2010.43.3.270 (Korean, re.kr [PDF; 598 kB ]).
  • Mark D. Norman, Julian K. Finn: World Octopod Fisheries . In: Patrizia Jereb, Clyde FE Roper, Mark D. Norman, Julian K. Finn (Eds.): Cephalopods of the world. An annotated and illustrated catalog of cephalopod species known to date (=  FAO Species Catalog for Fishery Purposes . Volume 3 , no. 4 ). Volume 3. Octopods and Vampire Squids. FAO, Rome 2014, ISBN 978-92-5107989-8 , pp. 9–21 ( fao.org [PDF; 26.3 MB ]).
  • Mark D. Norman, Julian K. Finn, FG Hochberg: Family Octopodidae . In: Patrizia Jereb, Clyde FE Roper, Mark D. Norman, Julian K. Finn (Eds.): Cephalopods of the world. An annotated and illustrated catalog of cephalopod species known to date (=  FAO Species Catalog for Fishery Purposes . Volume 3 , no. 4 ). Volume 3. Octopods and Vampire Squids. FAO, Rome 2014, ISBN 978-92-5107989-8 , pp. 36–215 ( fao.org [PDF; 26.3 MB ]).
  • James F. Peyla, Clyde F. Roper, Michael J. Sweeney, Michael Vecchione: Condition of the Sasaki / Albatross Cephalopod Collection at the US National Museum of Natural History . In: Marine Fisheries Review . tape 80 , no. 4 , 2018, ISBN 978-92-5107989-8 , pp. 83-88 , doi : 10.7755 / MFR.80.4.2 ( noaa.gov [PDF; 1.7 MB ]).
  • Madoka Sasaki: Report on cephalopods collected during 1906 by the United States Bureau of Fisheries steamer Albatross in the northwestern Pacific . In: Proceedings of the United States National Museum . tape 57 , no. 2310 , 1920, pp. 163–203, panels 23–26 , doi : 10.5479 / si.00963801.57-2310.163 ( si.edu [PDF; 3.5 MB ]).
  • Madoka Sasaki: A Monograph of the Dibranchiate Cephalopods of the Japanese and Adjacent Waters . In: Journal of the Faculty of Agriculture, Hokkaido Imperial University . tape 20 , Supplement, 1929, pp. 1-357 ( handle.net ).
  • Xiao-Dong Zheng, Yao-Sen Qian, Chang Liu, Qi Li: Octopus minor . In: José Iglesias, Lidia Fuentes, Roger Villanueva (eds.): Cephalopod Culture . Springer, New York, Heidelberg, Dordrecht, London 2014, ISBN 978-94-017-8647-8 , chap. 3 , p. 415-426 , doi : 10.1007 / 978-94-017-8648-5_22 .

Individual evidence

  1. ↑ a b c d e f g Mark D. Norman, Julian K. Finn, FG Hochberg: Family Octopodidae , here pp. 200–201.
  2. ↑ a b Madoka Sasaki: A Monograph of the Dibranchiate Cephalopods of the Japanese and Adjacent Waters , here pp. 90-94.
  3. ↑ a b c d e f g h i Xiao-Dong Zheng, Yao-Sen Qian, Chang Liu, Qi Li: Octopus minor .
  4. ↑ Octopus minor in the endangered Red List species the IUCN 2018 Posted by: L. Allcock and M. Taite, 2018. Retrieved on December 21 of 2019.
  5. ↑ a b Do Hoon Kim et al .: Optimal economic fishing efforts in Korean common octopus Octopus minor trap fishery .
  6. ^ FG Hochberg: The parasites of Cephalopods: A review .
  7. ↑ Xin Du, Chao Dong, Shi-Chun Sun: Octopicola huanghaiensis n. Sp. (Copepoda: Cyclopoida: Octopicolidae), a new parasitic copepod .
  8. ↑ Madoka Sasaki: Report on cephalopods collected during 1906 by the United States Bureau of Fisheries steamer Albatross in the northwestern Pacific .
  9. ↑ Ian G. Gleadall, M. Alejandro Salcedo-Vargas: Catalog of the Cephalopoda Specimens in the Zoology Department of Tokyo University Museum .
  10. ↑ James F. Peyla et al .: Condition of the Sasaki / Albatross Cephalopod Collection at the US National Museum of Natural History .
  11. ↑ Ian G. Gleadall: A note on the Cephalopoda type specimens in the Zoology Department of Tokyo University Museum .
  12. ^ Mark D. Norman, Julian K. Finn, FG Hochberg: Family Octopodidae , here p. 187.
  13. ^ Mark D. Norman, Julian K. Finn: World Octopod Fisheries .
  14. ^ Hyo Jin Lee, Gi Beum Kim: Concentration of Heavy Metals in Octopus minor in Seosan, Chungnam and Food Safety Assessment .
  15. ↑ Bo-mi Kim et al .: The genome of common long-arm octopus Octopus minor .
  16. ↑ Cheng, Rubin et al .: Determination of the complete mitochondrial DNA sequence of Octopus minor.
  17. ↑ Eiko Iwakoshi, Miki Hisada, Hiroyuki Minakata: Cardioactive peptides isolated from the brain of a Japanese octopus, Octopus minor .