Naso brevirostris 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Acanthuridae

Scientific Name: Naso brevirostris (Cuvier, 1829)
Common Name(s):
English Palefin Unicornfish, Brown Unicornfish, Longnose Unicornfish, Shortnosed Kala, Short-nosed Unicornfish, Shortnose Unicornfish, Shortsnout Unicornfish, Spotted Unicornfish
French Corne, Nasique, Nason à Rostre Court, Nason Pointillé
Cyphomycter coryphaenoides Smith, 1955
Naseus brevirostris Cuvier, 1829
Naseus brevirostris Valenciennes, 1835
Naso brevirostris (Valenciennes, 1835)
Taxonomic Notes: Naso brevirostris is widespread throughout the Indo-Pacific region, genetic studies conducted by Horne et al. (2008) did not find any evidence of geographic population structure even at the largest spatial scales.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2010-05-04
Assessor(s): Choat, J.H., Abesamis, R., Clements, K.D., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.
Reviewer(s): Edgar, G. & Kulbicki, M.
Naso brevirostris is widespread and cosmopolitan, occupying a wide range of habitats. It is the most abundant Naso on the Great Barrier Reed and in the central Indian Ocean (Western Australia and Cocos-Keeling  Islands (J.H. Choat pers. comm. 2010). It is not specifically targeted in multi-species fisheries. There is no evidence of declines from harvesting. It occurs in a marine protected areas in parts of its range. It is therefore listed as Least Concern.

Geographic Range [top]

Range Description:Naso brevirostris is found from the Red Sea south to Durban, eastwards to Pitcairn Islands and Hawaiian Islands, northwards to southern Japan, southwards to Lord Howe Island and Ningaloo Reef off western Australia. In the eastern Pacific, it is found in the Galapagos Islands.
Countries occurrence:
American Samoa; Australia; Bangladesh; British Indian Ocean Territory; Brunei Darussalam; Cambodia; China; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Disputed Territory (Paracel Is., Spratly Is.); Djibouti; Ecuador (Galápagos); Egypt; Eritrea; Fiji; French Polynesia; French Southern Territories (Mozambique Channel Is.); Guam; Hong Kong; India (Andaman Is., Nicobar Is.); Indonesia; Israel; Japan; Jordan; Kenya; Kiribati (Gilbert Is., Kiribati Line Is., Phoenix Is.); Korea, Republic of; 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; Pitcairn; Réunion; Samoa; Saudi Arabia; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Tokelau; Tonga; Tuvalu; United States (Hawaiian Is.); United States Minor Outlying Islands (Howland-Baker Is., Johnston I., Midway Is., US Line Is., Wake Is.); Vanuatu; Viet Nam; Wallis and Futuna; Yemen
FAO Marine Fishing Areas:
Indian Ocean – western; Indian Ocean – eastern; Pacific – northwest; Pacific – southwest; Pacific – western central; Pacific – southeast; Pacific – eastern central
Additional data:
Lower depth limit (metres):122
Upper depth limit (metres):2
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Naso brevirostris was recorded as occasional in terms of relative abundance in the northern Bismarck Sea, Papua New Guinea and in Raja Ampat, Indonesia (Allen 2009, 2003b). It is moderately common in Milne Bay Province, Papua New Guinea (Allen 2003). It is rare in the American Samoa National Park (National Park of Samoa Checklist of Fishes, accessed 21 April 2010). It is rare in the Philippines from fish visual census surveys (R. Abesamis and C. Nanola pers. comm. 2010). It is the most abundant Naso in Cocos (J.H. Choat pers. comm. 2010).
At Moorea, French Polynesia, SPOT satellite images allowed estimation of the surface area of fringing reef (1,076 ha), barrier reef (3,788 ha) and outer slop (493 ha). A total of 30,843 individuals were recorded in this area in fish visual surveys conducted from 1990-1993 (Lecchini et al. 2006). It is rare in the fish landings data from Guam (<1%) of the acanthurid fishery (Division of Aquatic and Wildlife Resources unpub. data). It is not recorded from the fishery in Saipan during 2008-2009 (P. Houk unpub. data).

In Kenya, landings during 1978-2001 for families that are less important in commercial catches (e.g., scarinae and Acanthuridae) showed rising catches (1978-1984) followed by a general decline during the 1990s, but the landings for the scarinae showed a rising trend in recent years (Kaunda-Arara et al. 2003).
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Naso brevirostris occurs on coral reefs or over rocky substrata. Juveniles and subadults graze on benthic algae; adults feed primarily on zooplankton (Randall 2001b). Food items include green filamentous algae and gelatinous zooplankton (Choat et al. 2002). Ontogenetic change in diet tends to occur by at least 20 cm (SL) (Green and Bellwood 2009).

The number of sagital increments in a study done by Choat and Axe (1996) suggest that members of the genus Naso attain the same maximum ages as the other Acanthurids, in excess of 20 years for this species. Maximum age was 25 years (Choat and Robertson 2002a).

The sexes are separate and there is evidence of sexual dimorphism in the caudal knives which are relatively larger in males (J.H. Choat pers. comm. 2010). This species was observed to form spawning aggregations on the Great Barrier Reef (Johannes 1981, Squire and Samoilys unpub.). Size at sexual maturity is 250 mm (Choat and Robertson 2002a). The large pelagic larvae persist in the pelagic environment for approximately 90 days (B.Victor pers. comm. in Horne et al. 2008).

Use and Trade [top]

Use and Trade: Naso brevirostris is captured for food. It is usually caught in traps or by spearing. It is a minor component of the aquarium trade (Global Marine Aquarium Database accessed 19 March 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. Its distribution overlaps with several marine protected areas within its range. In Queensland, Australia, there is a recreational catch limit of five per species and a minimum size limit of 25cm (Department of Primary Industries accessed 8 April 2010).

Citation: Choat, J.H., Abesamis, R., Clements, K.D., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Naso brevirostris. The IUCN Red List of Threatened Species 2012: e.T177990A1513480. . Downloaded on 18 June 2018.
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