Ctenochaetus binotatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Acanthuridae

Scientific Name: Ctenochaetus binotatus Randall, 1955
Common Name(s):
English Two-spot Bristletooth, Twospot Surgeonfish
Ctenochaetus oculocoeruleus Fourmanoir, 1966

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): McClenachan, L., Edgar, G. & Kulbicki, M.
Ctenochaetus binotatus is widely distributed and is common and abundant in parts of its range. It is harvested for food and for the aquarium trade but not at high levels. There are no major threats known. It is found in a number of marine reserves in parts of its distribution. It is therefore listed as Least Concern.

Geographic Range [top]

Range Description:Ctenochaetus binotatus is widespread in the Indo-Pacific from East Africa to the Tuamoto archipelago and Mangareva, northwards to southern Japan, and southwards to Elizabeth and Middleton reefs with juveniles ranging to Sydney, New South Wales. It is absent from the Line and Marquesan Islands.
Countries occurrence:
American Samoa; Australia; British Indian Ocean Territory; Brunei Darussalam; Cambodia; China; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Disputed Territory (Paracel Is., Spratly Is.); Fiji; French Polynesia; French Southern Territories (Mozambique Channel Is.); Guam; Hong Kong; India (Andaman Is., Nicobar Is.); Indonesia; Japan; Kenya; Kiribati (Gilbert Is., Phoenix Is.); Macao; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Micronesia, Federated States of ; Mozambique; Myanmar; Nauru; New Caledonia; Niue; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; RĂ©union; Samoa; Seychelles; Singapore; Solomon Islands; South Africa; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Tokelau; Tonga; Tuvalu; United States Minor Outlying Islands; Vanuatu; Viet Nam; Wallis and Futuna
FAO Marine Fishing Areas:
Indian Ocean – western; Indian Ocean – eastern; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
Additional data:
Lower depth limit (metres):55
Upper depth limit (metres):2
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Ctenochaetus binotatus is common and locally abundant in the Philippines (R. Abesamis and C. Nanola pers. comm. 2010). It was recorded as common in terms of relative abundance in Palawan, Philippines, Milne Bay Province, northern Bismarck Sea, Papua New Guinea and Raja Ampat, Indonesia (Werner and Allen 2000; Palawan Council for Sustainable Development unpub. data; Allen, 2003, 2003b, 2009). It is common in the American Samoa National Park (National Park of Samoa Checklist of Fishes accessed 21 April 2010).
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology: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). On the Great Barrier Reef, this species is generally found deeper than C. striatus. Juveniles are associated with rubble substrata (K.D. Clements pers. comm. 2010). 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).


Off Lizard Island, in the northern GBR, otolith increment counts suggests a larval period of 47 to 74 days. The growth rate of this species decreased after settlement (Lou 1993). A maximum age of 25 years was recorded from the Great Barrier Reef and length of 15.1 cm (TL) (J.H. Choat pers. comm. 2010). 


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). Ctenochaetus binotatus recruits all year round in the central Visayas with peaks during the NE monsoon (Dec-Feb) at 0.2 fish/250 m2 (R. Abesamis unpub. data).

Use and Trade [top]

Use and Trade: Ctenochaetus binotatus is a component of the marine aquarium trade. Online prices range from $34.95-$59.99 per individual (L. Rocha pers. comm. 2010). It is a targeted food fish in western Thailand (Allen 2005). It is rare in the Guam fishery (J. McIlwain pers. comm. 2010).

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.

Citation: Clements, K.D., Choat, J.H., Abesamis, R., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Ctenochaetus binotatus. The IUCN Red List of Threatened Species 2012: e.T177955A1501829. . Downloaded on 23 September 2018.
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