Habitat and Ecology
A. japonicus ingests organic matter, bacteria, protozoa, diatoms as well as plant and animal detritus and re-utilizes residual food and feces. It becomes inactive when water temperature exceeds 18 Â°C, and will aestivate at water temperatures about 20â24.5Â°C. In some regions of China, aestivation can last up to four years (Choo 2008).
A. japonicus matures considerably earlier than other temperate species, at about two years (Skewes et al. 2002; Chen 2003). Larval duration for this species is 12-13 days (Chen 2003). This species typically grows to 20 cm in four years (Izumi 1991).
Generation length is largely unknown for these species. Body size is not a good indicator of age or longevity. There is some indication, however, that many echinoderms do not go through senescence, but simply regenerate. Therefore generation length cannot be estimated, but is assumed to be greater than several decades (20-40 years) in a natural, undisturbed environment.
Molecular Biology and Genetics
Barcode data: Apostichopus japonicus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Apostichopus japonicus
Public Records: 9
Specimens with Barcodes: 10
Species With Barcodes: 1
Statistics of barcoding coverage: Stichopus japonicus
Public Records: 0
Specimens with Barcodes: 12
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
Catches of this species have significantly declined over the past 50 years throughout its range, and wild populations of this species are considered mostly extirpated from China (Libin Zhang pers comm 2012).
In China, wild capture fisheries have declined significantly in two provinces of Shandong and Liaoning, which historically represented the heart of their distribution. Wild catches of this species in these and surrounding areas declined from 130-140 tonnes in the 1950s to values between 26 and 40 tonnes in the 1970s (Choo 2008). Current landings of wild caught Apostichopus japonicus in China are considered non existent (Sloan 1995). The soaring price for this species has stimulated the development of aquaculture and sea ranching. It has been reported that the aquaculture production of A. japonicus in China reached 5,800 tonnes dry weight in 2002, compared to harvest levels of 470 tonnes dry weight in the same year (Chen 2004). In 2010, the aquaculture production of A. japonicus in Shandong was 66,300 tons and accounted for 50% of that in China, while the production in Liaoning was 59,764 tons and accounted for 45% of China's production (Libin Zhang pers comm 2012).
A. japonicus is the most common sea cucumber species in Japan. The catch of A. japonicus in Japan has decreased at least 30% over the past 30 years, dropping from over 10,000 tonnes (wet weight) in 1978 to 7,133 tonnes in 1987 (Bruckner et al. 2003). In Japan, between 2000-2005 the range for landings was between 7,000-9,000 tonnes per year (Choo 2008), and this trend seems to be stable. Here, it is captured by several methods such as dredge net, hook, spear and diving (Choo 2008). In the year 2000, Japan started developing hatchery techniques, and in Russia there is a hatchery for sea cucumber production, which is presumed to be of A. japonicus, that started in 2003 (Choo 2008).In Russia, Konstantinova (2004) noted that the sea cucumber (species not identified in the article, but likely to be A. japonicus) resources in Primorsky Krai, located in the extreme southâeastern region of the Russian Federation, have decreased to 16â20% of the level of the stock that existed in the 1960s. The majority of the current stock comprises of specimens of around 40â60 g which were below the marketable size (Choo 2008).
The species is commonly exploited for food from the capture fishery in the Democratic People's Republic of Korea and is reported to be severely exploited (Choo 2008). Capture production of A. japonicus from the Republic of Korea showed an average production of about 1,902 tonnes from 1990 to 1999, while the average capture production from 2000 to 2005 was 1,120 tonnes (Choo 2008), representing a decline of about 40% over 10-15 years.
In Japan and Korea, 13,371 tonnes of this species were harvested each year in the early 1980s (Bruckner et al. 2003).
In 2005 there was an initiative in Chile to introduce A. japonicus to start an aquaculture venture (Choo 2008).
Apostichopus japonicus has been cultured for several years. The price of this species when cultured is very high compared to wild caught high-grade species.
Except for Japan, all the countries in the Asian region generally lack conservation measures for the sea cucumber fisheries (Choo 2008). The oldest management activity in Japan, which continues to this day, has been to set aside certain localities as breeding reserves where sea cucumber fishing is strictly prohibited. Currently, the Sea-Area Fishery Adjustment Commission of Japan oversees fishery management and fisheries cooperative association work at the community level. Some of the measures include no fishing during spawning activity, maximum total annual catch, regulation of the minimum catch size, mesh size restriction, and no fishing areas (Choo 2008). There is an example of a recovery plan in Japan in Ohmura Bay where an increase of 18% in a period of one year has been noted (Mitsunaga et al. 2006).
With the inclusion of Isostichopus fuscus in CITES Appendix III, a debate started whether the conservation of this group may be addressed with their inclusion in one of CITES appendices (Toral-Granda 2007), and no recent advances have been achieved on this matter.
Apostichopus japonicus is a species of sea cucumber in the family Stichopodidae. It is found in shallow temperate waters along the coasts of south east Asia and is commonly known as the Japanese spiky sea cucumber or the Japanese sea cucumber.
The Japanese sea cucumber has a cylindrical leathery body with blunt, thorny protuberances. At the anterior or front end there is a mouth surrounded by a ring of short feeding tentacles and at the posterior end is the anus. There are three different colour morphs, red, green and black.
Distribution and habitat 
The Japanese sea cucumber is found along the coast of Russia, China, Japan and Korea. The range extends from Alaska and Sakhalin Island to the Amami Islands, Japan. The red morphs are found on gravel beds offshore at depths of 40 metres (130 ft) or deeper while the other two colours are found intermingled on muddy and sandy bottoms at shallower depths. Although the red morph may breed red offspring due to its reproductive isolation in a different microhabitat, DNA studies have shown that there is a limited degree of genetic difference between it and the other two colour morphs while there is no significant difference between the black and green forms. In lagoons in southern Sakhalin, Russia, Japanese spiky sea cucumber are found on solid substrates among growth of the red alga Ahnfeltia tobuchiensis and in oyster beds (Crassostrea gigas).
The Japanese sea cucumber sifts through the sediment on the seabed with its tentacles and feeds on detritus and other organic matter including plant and animal remains, bacteria, protozoa, diatoms and faeces.
The sexes are separate in the Japanese sea cucumber. Males and females release a mass of gametes into the sea where fertilization takes place. In the laboratory, spawning from ripe gonads can be induced by varying the temperature at which the adults are kept or by use of the neuropeptide cubifrin. The planktonic larvae develop through several stages before settling on hard surfaces on the seabed, undergoing metamorphosis and becoming juveniles.
The Japanese sea cucumber lives in temperate seas. In locations where the water heats up excessively in summer it undergoes aestivation, going into a state of dormancy. In this state, feeding stops, the gut degenerates, the metabolism slows down and weight is lost. The threshold temperature is about 25 °C (77 °F), higher for smaller individuals and for those from the southern part of the range where the ambient water temperature is higher. This sea cucumber has been known to continue in aestivation in some areas of China for four years.
Fishery and aquaculture 
The Japanese sea cucumber is used for food. The largest fishery is in Japan where between 2000 and 2005, an average of 8,101 tonnes of this species were harvested annually. The red form is known there as "aka namako" and sells at a different price from "ao namako", the green morph and "kuro namako", the black one. In Russia and North Korea, overfishing has reduced populations considerably. Fishing methods include diving and hand collection at depths of up to 20 metres (66 ft) and the use of trawls at greater depths. In the 1920s, a "sea cucumber fork" was developed in China. It is operated from several small vessels working together and allows harvest from depths of up to 60 metres (200 ft).
The Japanese sea cucumber is also cultivated on a commercial scale in shallow ponds and by sea ranching in northern China, where production reached 5,865 tonnes in 2002. Rocks and tiles are placed on the bottom to provide settlement for larvae and protection from predators. Breeding programs are under way to improve growth rates and disease resistance and the genome is being sequenced. Hatchery techniques are being developed in Japan and China as are the preparation of suitable culture feeds and the investigation of the best methods of ranching. Albino forms and a thermally resistant strain that is less prone to aestivate are being developed in China.
- Paulay, Gustav (2010). "Apostichopus japonicus (Selenka, 1867)". World Register of Marine Species. Retrieved 2012-06-09.
- Poh-Sze Choo. "Population status, fisheries and trade of sea cucumbers in Asia". FAO. Retrieved 2012-06-09.
- Kanno, Manami ; Suyama, Yoshihisa; Li, Qi; Kijima, Akihiro (2006). "Microsatellite Analysis of Japanese Sea Cucumber, Stichopus (Apostichopus) japonicus, Supports Reproductive Isolation in Color Variants". Marine Biotechnology 8 (6): 672–685. doi:10.1007/s10126-006-6014-8.
- Dubrovskii, S. V.; Sergeenko, V. A. (2002). "Distribution Pattern of Far Eastern Sea Cucumber Apostichopus japonicus in Busse Lagoon (Southern Sakhalin)". Russian Journal of Marine Biology 28 (2): 87–93. doi:10.1023/A:1015336326263.
- Fujiwara, Atushi; Yamano, Keisuke; Ohno, Kaoru; Yoshikuni, Michiyasu (2010). "Spawning induced by cubifrin in the Japanese common sea cucumber Apostichopus japonicus". Fisheries Science 76 (5): 795–801. doi:10.1007/s12562-010-0262-2.
- Wang Renbo and Cheng Yuan. "Breeding and culture of the sea cucumber, Apostichopus japonicus, Liao". FAO: Fisheries and Aquaculture Department. Retrieved 2012-06-10.
- Du, H.; Bao, Z.; Hou, R.; Wang, S.; Su, H. et al. (2012). "Transcriptome Sequencing and Characterization for the Sea Cucumber Apostichopus japonicus (Selenka, 1867)". PLoSone (PLoSone) 7 (3). doi:10.1371/journal.pone.0033311.
- Liu, Y.; Li, F.; Song, B.; Sun, H. Zhang X.; Gu, B. (1996). "Study on aestivating habit of sea cucumber Apostichopus japonicus Selenka: ecological characteristics of aestivation.". Journal of Fishery Sciences of China 3: 41–48.
- "New Progress in Artificial Apostichopus Japonicus Breeding of Thermal Tolerant Strain and Albino Strain". IOCAS. 2010. Retrieved 2012-06-10.
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