Chestnut octopus (Octopus conispadiceus)
Source-cited species reference: taxonomy from WoRMS, biology from SeaLifeBase, occurrence map from GBIF, conservation from IUCN Red List, description from Wikipedia.
Octopus conispadiceus (commonly the chestnut octopus) is a species of long-ligula octopus, provisionally placed in the genus Octopus. It was first described by Madoka Sasaki in 1917 based on specimens bought at a fish market in Sapporo, Japan.
- Scientific name
- Octopus conispadiceus
- Authority
- (M. Sasaki, 1917)
- Family
- Octopodidae
- Order
- Octopoda
- Maximum length
- 150 cm
- Habitat zone
- benthic
- Iucn red list
- Least Concern
- Gbif occurrence records
- 315
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Mollusca · Class: Cephalopoda · Order: Octopoda · Family: Octopodidae · Genus: Octopus.
Accepted name: Octopus conispadiceus · Authority: (M. Sasaki, 1917) · Taxonomic status: accepted · AphiaID: 341963.
Synonyms and superseded combinations recorded for this taxon: Paroctopus conispadiceus (M. Sasaki, 1917); Polypus conispadiceus M. Sasaki, 1917.
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=341963 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (SeaLifeBase)
Measured values published by SeaLifeBase for Octopus conispadiceus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Maximum length: 150 cm · Habitat zone: benthic · Vulnerability index: 90 of 100 · Fishery importance: commercial.
SeaLifeBase notes: Also caught by bottom longline. Females grow larger than males (Ref. 3722).
Source: SeaLifeBase species summary (SpecCode 57444) — https://www.sealifebase.se/summary/Octopus-conispadiceus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Distribution and occurrence records (GBIF)
315 georeferenced occurrence records for Octopus conispadiceus are published through GBIF from 3 countries or marine areas. The map above plots 6 distinct locations from a sample of 315 records, omitting 2 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.
Most records by country or area: Japan (311); Korea, Republic of (2); Russian Federation (2).
Marine regions with a valid WoRMS distribution record: West North Pacific.
Source: GBIF Occurrence Search (taxonKey 2289646) — https://www.gbif.org/occurrence/search?taxon_key=2289646&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=341963 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.
Conservation status (IUCN Red List)
The IUCN Red List assesses Octopus conispadiceus (Sasaki, 1917) as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.
Source: IUCN Red List of Threatened Species (taxon 163397_1) — https://www.iucnredlist.org/species/163397_1/0; GBIF IUCN Red List category endpoint (taxonKey 2289646) — https://api.gbif.org/v1/species/2289646/iucnRedListCategory. Accessed 2026-09-23.
Description and natural history (Wikipedia)
O. conispadiceus is large, with a mantle length of up to 210 millimeters and a total length of at least 120 centimeters; its arms are moderate in length, around three times the length of the mantle. There are 140 to 150 suckers on each arm in males and 170 to 190 in females, and suckers are larger in males than females. O. conispadiceus is firm and muscular, with smooth skin, and light gray-blue in color with a white line across its head. It has seven rows of teeth and an ink sac. O. conispadiceus has small eyes.
O. conispadiceus is found in cold temperate waters off northern Japan and the Kuril Islands. It is a benthic shelf species, living from depths of around 50 to 100 meters, mostly in sandy or muddy substrates.
O. conispadiceus reaches maturity quickly, around 10 to 11 months in cold waters. Juveniles look much like adults, but have a different skin texture. The species has a short life span, with estimates between under two years and three to four years. Females lay from 400 up to 1,200 eggs at a time; the eggs are very large, up to 28 millimeters. The size of the eggs suggests that hatchlings are benthic.
O. conispadiceus is fished commercially in Japan. It is the second most common species of octopus in fish markets in Hokkaido, and is sometimes bycatch in gillnet fishing, especially in Russia
Source: Wikipedia: Octopus conispadiceus — https://en.wikipedia.org/wiki/Octopus_conispadiceus (CC BY-SA 4.0). Accessed 2026-09-23.
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