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Thenus orientalis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA ARTHROPODA MALACOSTRACA DECAPODA SCYLLARIDAE

Scientific Name: Thenus orientalis
Species Authority: (Lund, 1793)
Common Name(s):
English Flathead Lobster
French Cigale raquette
Spanish Cigarra chata
Synonym(s):
Sagaritis orientalis Billberg, 1820
Scyllarus orientalis Lund, 1793
Scyllibacus orientalis Desjardins, 1831
Taxonomic Notes: This species was previously known as one species (Thenus orientalis), but now has been split into five separate species (Burton and Davie 2007).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2013
Date Assessed: 2009-12-03
Assessor(s): Chan, T.Y., Butler, M., Cockcroft, A., MacDiarmid, A., Wahle, R. & Ng Kee Lin, P.
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.
Justification:

Thenus orientalis has been assessed as Least Concern. This species has a wide distribution, although clarification is required in some parts of its range. It is harvested throughout its range, and known to be over-exploited locally in some regions. Although declines have occurred, the ecological characteristics of slipper lobsters make them resistant to extinction as they are highly fecund with well-connected populations via long-lived larvae.

Geographic Range [top]

Range Description: This species is found from the southern Red Sea, Arabian Gulf, Gulf of Thailand, Viet Nam, Indonesia, Philippines and southern Japan (Burton and Davie 2007). It may also be found in India but new specimens are needed to confirm this. This species was recently mistaken for Thenus parindicus and Thenus australiensis, both of which are fished off eastern Australian. As such reports of this species in fisheries reports of the area are false (P. Davie pers. comm. 2010).
Countries:
Native:
Bahrain; Cambodia; China (Fujian, Guangdong, Hainan, Zhejiang); Comoros; Djibouti; Ethiopia; Hong Kong; India; Indonesia; Iran, Islamic Republic of; Japan; Kenya; Kuwait; Macao; Madagascar; Malaysia; Maldives; Mozambique; Myanmar; Oman; Pakistan; Philippines; Qatar; Saudi Arabia; Seychelles; Singapore; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; United Arab Emirates; Viet Nam; Yemen
FAO Marine Fishing Areas:
Native:
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This is a common and well-studies species. It is caught as by-catch in some areas, and is targeted in others (Radhakrishnan et al. 2005). There have, however, been collapses in some fisheries of this species off the Indian coast (Radhakrishnan et al. 2005).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This species is found on sandy coarse substrates and mud with possibly shells and gravel at depths of  8 - 100 m, although it is more commonly found from 10 - 50 m (Holthuis 1991). This is a slow growing species with a well-defined breeding period (Radhakrishnan et al. 2005). The high fecundity, wide dispersal and long-lived nature of this species larvae render this species resilient to complete extirpation from an area (Mikami and Greenwood 1997).
Systems: Marine

Use and Trade [top]

Use and Trade: This species is known to be caught in targeted fisheries and as by-catch (Holthuis 1991). No fisheries figures for solely this species are available, however.

Threats [top]

Major Threat(s):

This species is currently threatened by over-fishing, which has caused localized declines and collapses of some fisheries (Radhakrishnan et al. 2005). 

Conservation Actions [top]

Conservation Actions: There are some management measures in place such as minimum legal sizes in India, although this requires more stringent regulation (Radhakrishnan et al. 2005). 
Further research on this species is recommended to clarify its distribution and threats.

Citation: Chan, T.Y., Butler, M., Cockcroft, A., MacDiarmid, A., Wahle, R. & Ng Kee Lin, P. 2013. Thenus orientalis. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 19 September 2014.
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