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Naso annulatus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES ACANTHURIDAE

Scientific Name: Naso annulatus
Species Authority: (Quoy & Gaimard, 1825)
Common Name/s:
English Whitemargin Unicornfish, Ringtailed Unicornfish, Nosefish, Long-horn Unicornfish, Unicornfish, Banded Unicornfish
Synonym/s:
Naso herrei Smith, 1966
Priodon annulatus Quoy & Gaimard, 1825

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2010-05-04
Assessor/s: Abesamis, R., Clements, K.D., Choat, J.H., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.
Reviewer/s: Edgar, G. & Kulbicki, M.
Justification:
Naso annulatus is widespread in the Indo-Pacific region and is common in parts of its range. It is a targeted food fish in the Philippines and is harvested for food elsewhere in its range. There are no indications of population declines by harvesting. There are no major threats known and it is found in a number of marine protected areas in parts of its range. It is therefore listed as Least Concern.

Geographic Range [top]

Range Description: Naso annulatus is widespread in the Indo-Pacific and is found from the Red Sea to Natal, eastwards to the Hawaiian Island, Tuamotu Archipelago and Marquesas, northwards to Honshu, Japan, southwards to Lord Howe Island and Norfolk Island. It is also found in the eastern Pacific from Clipperton Island (Robertson and Allen 1996).
Countries:
Native:
American Samoa (American Samoa); Australia; Brunei Darussalam; Cambodia; China; Christmas Island; Comoros; Cook Islands; Costa Rica (Cocos I.); Disputed Territory (Paracel Is., Spratly Is.); Djibouti; Egypt; Eritrea; Fiji; France (Clipperton I.); French Polynesia; French Southern Territories (Mozambique Channel Is.); Guam; Hong Kong; India; Indonesia; Israel; Japan; Jordan; Kiribati (Gilbert Is.); Macao; Madagascar; Malaysia; Marshall Islands; Mayotte; Micronesia, Federated States of ; Mozambique; Nauru; New Caledonia; Niue; Norfolk Island; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Samoa; Saudi Arabia; Seychelles; Solomon Islands; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Tonga; Tuvalu; United States (Hawaiian Is.); Vanuatu; Viet Nam; Wallis and Futuna; Yemen
FAO Marine Fishing Areas:
Native:
Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southeast; Pacific – southwest; Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: In the central Philippines, density and biomass of herbivorous fish in reserves had positive relationships with duration of reserve protection. Acanthuridae and Labridae (parrotfishes) were the major families that increased in biomass inside reserves with duration of reserve protection. Herbivore biomass inside reserves compared to fished sites was on average higher as years of protection increases. Naso annulatus mean biomass values (kg per 500 m2) recorded in 3 reserves were 0.67 (0.5 to 4 yr of protection), 0.10 (5 to 7 years of protection), 8.16 (8 to 11 years of protection), respectively (Stockwell et al. 2009).

This species is common in Tubbataha, Spratlys and northern Palawan (C. Nanola, S. Conales, Jr. and R. Abesamis pers. comm. 2010). It is uncommon in Guam and Saipan based on fish visual census (J. McIlwain unpub. data) and rare in the Guam and Saipan Acanthurid fishery (<1%) (Guam Division of Aquatic and Wildlife Resources unpub. data, P. Houk unpub. data). It was recorded as occasional in terms of relative abundance in the northern Bismarck Sea, Papua New Guinea (Allen 2009). It is moderately common, usually adjacent to steep outer slopes in Milne Bay Province, Papua New Guinea (Allen 2003). It is uncommon in the American Samoa National Park (National Park of Samoa Checklist of Fishes accessed 21 April 2010).

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).
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: Naso annulatus is found in shallow waters, with large adults typically found on steep drop-offs in more than 25 m, usually in small aggregations (Randall 2001a). It feeds on green filamentous algae as juveniles and gelatinous zooplankton as adults (Choat 1991, Choat and Clements 1998, Choat et al. 2002b). Ontogenetic change in diet tends to occur by at least 20 cm (SL) (Green and Bellwood 2009). Maximum age was 23 years in the Great Barrier Reef (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. The males get the longer caudal filaments (J.H. Choat pers. comm. 2010).
Systems: Marine

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: Abesamis, R., Clements, K.D., Choat, J.H., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Naso annulatus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 16 April 2014.
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