Ibacus novemdentatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Scyllaridae

Scientific Name: Ibacus novemdentatus Gibbes, 1850
Common Name(s):
English Smooth Fan Lobster

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2011
Date Assessed: 2009-12-03
Assessor(s): MacDiarmid, A., Cockcroft, A. & Butler, M.
Reviewer(s): Collen, B., Livingstone, S. & Richman, N.
Contributor(s): Batchelor, A., De Silva, R., Dyer, E., Kasthala, G., Lutz, M.L., McGuinness, S., Milligan, H.T., Soulsby, A.-M. & Whitton, F.
Ibacus novemdentus has been assessed as Least Concern due its wide distribution. While this species is harvested as by-catch, it is not taken across its entire range and is not thought to pose a significant threat to the population at this time.

Geographic Range [top]

Range Description:This species is known from the Indo-west Pacific and East Africa. It ranges from: Kenya to Cape Province, Madagascar to the Mauritius-Seychelles Ridge, from Korea and Japan, to the South China Sea including Taiwan, Viet Nam, the Philippines, and Western Australia (Holthuis 1991).
Countries occurrence:
Australia (Western Australia); Cambodia; China (Guangdong, Guangxi); Hong Kong; Indonesia (Bali, Jawa, Kalimantan, Lesser Sunda Is., Maluku, Papua, Sulawesi, Sumatera); Japan (Honshu, Kazan-retto, Kyushu, Marcus I., Nansei-shoto, Ogasawara-shoto, Shikoku); Kenya; Korea, Democratic People's Republic of; Korea, Republic of; Macao; Malaysia (Peninsular Malaysia, Sabah, Sarawak); Mauritius (Mauritius (main island), Rodrigues); Mozambique; Papua New Guinea (Papua New Guinea (main island group)); Philippines; Seychelles (Aldabra, Seychelles (main island group)); Somalia; South Africa (Eastern Cape Province, Northern Cape Province); Taiwan, Province of China (Taiwan, Province of China (main island)); Tanzania, United Republic of; Thailand; Viet Nam
FAO Marine Fishing Areas:
Indian Ocean – western; Indian Ocean – eastern; Pacific – western central
Additional data:
Lower depth limit (metres):400
Upper depth limit (metres):37
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:There is no population information available. This species is caught as by-catch throughout its range.

The combined landings of this species  and I. ciliatus reported for Taiwan, are as follows (tonnes):
1989 - 663; 1990 - 310; 1991 - 389; 1992 - 514; 1993 - 456; 1994 - 236; 1995 - 1,224; 1996 - 1,115; 1997 - 642; 1997 - 642; 1998 - 696; 1999 - 676; 2000 - 1,600; 2001 - 1,607; 2002 - 1,005; 2003 - 1,637; 2004 - 1,596; 2005 - 1,553; 2006 - 1,570 (FISHSTAT Plus 2000). Further species specific information is needed on whether the increases or decreases in the landings reflect changes in fishing effort.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species is found on soft sediments at a depth range of 37 - 400 m (Holthuis 1991).

Use and Trade [top]

Use and Trade: Captured as bycatch and used as food.

Threats [top]

Major Threat(s): This species is harvested for food in Korea, Taiwan and Japan and is sold fresh in local markets, where it is taken by trawlers and long line (Holthuis 1991).

There is no targeted fishery for this species in the Western Indian Ocean, although it is common in trawls, with numbers as high as 22.6 kg per hour (Ivanov and Krylov 1980). The by-catch of this species is not thought to pose a significant threat to the population at this time.

Conservation Actions [top]

Conservation Actions: There are no species-specific conservation measures in place for this species.

Further research is needed on the extent of this fishery, with data on fishing effort and landings.

Classifications [top]

9. Marine Neritic -> 9.4. Marine Neritic - Subtidal Sandy
9. Marine Neritic -> 9.5. Marine Neritic - Subtidal Sandy-Mud
9. Marine Neritic -> 9.6. Marine Neritic - Subtidal Muddy
10. Marine Oceanic -> 10.1. Marine Oceanic - Epipelagic (0-200m)
10. Marine Oceanic -> 10.2. Marine Oceanic - Mesopelagic (200-1000m)

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.1. Intentional use: (subsistence/small scale) [harvest]
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Negligible declines ⇒ Impact score:Low Impact: 4 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.3. Unintentional effects: (subsistence/small scale) [harvest]
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Negligible declines ⇒ Impact score:Unknown 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.4. Unintentional effects: (large scale) [harvest]
♦ timing:Ongoing ♦ scope:Unknown ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

♦  Food - human
 Local : ✓   National : ✓ 

Bibliography [top]

Gibbes, L.R. 1850. On the carcinological collections of the cabinets of Natural history in the United States with an enumeration of the species contained therein, and descriptions of new species. Proceedings American Association Advancement Science 3: 165-201.

Groeneveld, J.C., Greengrass, J.L., Branch, G.M. and McCue, S.L. 2005. Fecundity of the deep-water spiny lobster Palinurus delagoae off eastern South Africa. Western Indian Ocean Journal of Marine Science 4(2): 135-143.

Holthuis, L.B. 1991. Marine lobsters of the world. An annotated and illustrated catalogue of species of interest to fisheries known to date. FAO species catalogue 13(125). FAO, Rome.

IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.1). Available at: (Accessed: 30 June 2017).

Ivanov, B.G. and Krylov, V.V. 1980. Length-weight relationship in some common prawns and lobsters (Macrura, Natantia and Reptantia) from the western Indian Ocean. Crustaceana 38: 279-289.

Citation: MacDiarmid, A., Cockcroft, A. & Butler, M. 2011. Ibacus novemdentatus. The IUCN Red List of Threatened Species 2011: e.T170023A6710751. . Downloaded on 22 July 2018.
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