Ctenochaetus truncatus 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Acanthuridae

Scientific Name: Ctenochaetus truncatus
Species Authority: Randall & Clements, 2001
Common Name(s):
English Squaretail Bristletooth, Indian gold-ring bristle-tooth

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2010-05-07
Assessor(s): Clements, K.D., Choat, J.H., Abesamis, R., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.
Reviewer(s): Edgar, G. & Kulbicki, M.
Ctenochaetus truncatus is widespread in the Indian Ocean, achieves high abundances in Christmas Island and is common in some areas of its distribution. It is not targeted and is caught only incidentally. There are no major threats known and it is found in a number of marine reserves in parts of its range. It is therefore listed as Least Concern.

Geographic Range [top]

Range Description:Ctenochaetus truncatus is found from East Africa from Kenya to Natal to the Andaman Sea off Thailand, Cocos Keeling Islands and Christmas Island.
Countries occurrence:
British Indian Ocean Territory; Christmas Island; Cocos (Keeling) Islands; Comoros; French Southern Territories (Mozambique Channel Is.); India (Andaman Is., Nicobar Is.); Indonesia; Kenya; Madagascar; Malaysia; Maldives; Mauritius; Mayotte; Mozambique; Myanmar; Oman; Réunion; Seychelles; Somalia; South Africa; Sri Lanka; Tanzania, United Republic of; Thailand
FAO Marine Fishing Areas:
Indian Ocean – western; Indian Ocean – eastern; Pacific – western central
Lower depth limit (metres):25
Upper depth limit (metres):1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Ctenochaetus truncatus is one of the most abundant surgeonfishes on Christmas Island (Allen and Steene 1979). It is unusual in being much more common there than C. striatus (Randall and Clements 2001). It is common in the Seychelles (L. Rocha pers. comm. 2010) and Sodwana Bay (K.D. Clements pers. comm. 2010).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Ctenochaetus truncatus inhabits shallow water, coral-reef and rocky reefs. The genus Ctenochaetus feed on fine detrital material. They whisk the sand or rocky substratum with their teeth and utilize suction to draw in the detrital material that consists of diatoms, small fragments of algae, organic material and fine inorganic sediment (Randall and Clements 2001).  Species of Ctenochaetus share the presence of a thick-walled stomach (Randall and Clements 2001), this character is significant with respect to the nutritional ecology of this genus (Choat et al. 2002b).

The sexes are separate among the acanthurids (Reeson 1983). Acanthurids do not display obvious sexual dimorphism, males assume courtship colours (J.H. Choat pers. comm. 2010).

Use and Trade [top]

Use and Trade: Ctenochaetus truncatus is a minor component of the marine aquarium trade. It sells online for $79.95 to $149.95 depending on size (bluezooaquatics.com accessed 20 April 2010). It is a targeted food fish in western Thailand (Allen 2005). It is caught incidentally as food in other parts of its range.

Threats [top]

Major Threat(s): There are no major threats known for this species.

Surgeonfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reef while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. The majority of surgeonfishes are exclusively found on coral reef habitat, and of these, approximately 80% are experiencing a greater than 30% loss of coral reef area and degradation of coral reef habitat quality across their distributions. However, more research is needed to understand the long-term effects of coral reef habitat loss and degradation on these species' populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that recruit into areas with live coral cover, especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats (Comeros-Raynal et al. 2012).

Conservation Actions [top]

Conservation Actions: There are no species-specific conservation measures in place for this species. However, its distribution overlaps several marine protected areas within its range.

Classifications [top]

9. Marine Neritic -> 9.2. Marine Neritic - Subtidal Rock and Rocky Reefs
suitability: Suitable  
9. Marine Neritic -> 9.8. Marine Neritic - Coral Reef -> 9.8.3. Foreslope (Outer Reef Slope)
suitability: Suitable  

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over part of range
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
3. Monitoring -> 3.1. Population trends
3. Monitoring -> 3.2. Harvest level trends

♦  Food - human
 Local : ✓ 

♦  Pets/display animals, horticulture
 International : ✓ 

Bibliography [top]

Allen, G.R. and Steene, R.C. 1979. The fishes of Christmas Island, Indian Ocean. Australian Government Publishing Service, Canberra.

Allen, M. 2005. A post-tsunami assessment of coral reef fin-fish resources on the Andaman Sea coast of Thailand. In: Allen, G.R. and G.S. Stone (eds), Rapid Assessment Survey of Tsunami-affected Reefs of Thailand. Final Technical Report. November 15, 2005.

Choat, J.H., Clements, K.D. and Robbins, W.D. 2002b. The trophic status of herbivorous fishes on coral reefs. 1. Dietary analyses. Marine Biology 140: 613-623.

Comeros-Raynal, M.T., Choat, J.H., Polidoro, B.A., Clements, K.D., Abesamis, R., Craig, M.T., Lazuardi, M.E., McIlwain, J., Muljadi, A., Myers, R.F., Nañola Jr., C.L., Pardede, S., Rocha, L.A., Russell, B., Sanciangco, J.C., Stockwell, B., Harwell, H. and Carpenter, K.E. 2012. The likelihood of extinction of iconic and dominant components of coral reefs: the parrotfishes and surgeonfishes. PLoS ONE http://dx.plos.org/10.1371/journal.pone.0039825.

IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.2). Available at: http://www.iucnredlist.org. (Accessed: 17 October 2012).

Randall, J.E. 2001a. Surgeonfishes of the world. Mutual Publishing and Bishop Museum Press, Hawai'i, Honolulu, Hawaii.

Randall, J.E and Clements, K.D. 2001. Second revision of the surgeonfish genus Ctenochaetus (Perciformes: Acanthuridae), with descriptions of two new species. Indo-Pacific Fishes 32: 33.

Reeson, P.H. 1983. The biology, ecology and bionomics of the surgeonfishes, Acanthuridae. In: J.L. Munro (ed.), Caribbean coral reef fishery resources, pp. 178-190.

Citation: Clements, K.D., Choat, J.H., Abesamis, R., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Ctenochaetus truncatus. In: The IUCN Red List of Threatened Species 2012: e.T177992A1514533. . Downloaded on 27 November 2015.
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