|Scientific Name:||Acanthurus nigricauda|
|Species Authority:||Duncker & Mohr, 1929|
Acanthurus gahm subspecies nigricauda Duncker & Mohr, 1929
Acanthurus nigricaudus Duncker & Mohr, 1929
|Taxonomic Notes:||A. nigricauda x olivaceous hybrids have been observed in the Marshall Islands (Randall 2001a).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Clements, K.D., McIlwain, J., Choat, J.H., Abesamis, R., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.|
|Reviewer/s:||Davidson, L., Edgar, G. & Kulbicki, M.|
Acanthurus nigricauda is widespread in the Indo-Pacific Region and is common in parts of its range. It is harvested as food and is a component of the aquarium trade. Harvest is not considered a major threat globally and it occurs in a number of marine reserves in parts of its distribution. It is therefore listed as Least Concern.
|Range Description:||Acanthurus nigricauda is widespread in the Indo-Pacific and is found from East Africa to the Society Islands and Tuamotu Archipelago, northwards to Ryukyu Islands, Japan and southwards to the Great Barrier Reef, Australia and New Caledonia. It is absent from the Red Sea, Arabian Peninsula and the Hawaiian Islands.|
Native:American Samoa (American Samoa); Australia; British Indian Ocean Territory (Chagos Archipelago); Brunei Darussalam; Cambodia; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Disputed Territory (Paracel Is., Spratly Is.); Fiji; French Polynesia; French Southern Territories (the) (Mozambique Channel Is.); Guam; India (Andaman Is., Nicobar Is.); Indonesia; Japan; Kenya; Kiribati (Gilbert Is., Kiribati Line Is., Phoenix Is.); Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius (Mauritius (main island), Rodrigues); Mayotte; Micronesia, Federated States of; Mozambique; Myanmar; Nauru; New Caledonia; Niue; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Réunion; Samoa; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Tokelau; Tonga; Tuvalu; United States Minor Outlying Islands (Howland-Baker Is., US Line Is., Wake Is.); Vanuatu; Viet Nam; Wallis and Futuna
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
In the Philippines, Acanthurus nigricauda is common over sandy bottoms. Abundance estimates in Guam record 1 ind/500 m2 (J. McIlwain pers. comm. 2010). It is targeted in Guam and makes up 2% of the acanthurid community and 5% of the acanthurid fishery. It is uncommon to rare in fished areas (J. McIlwain unpub. data). Visual census surveys along Aceh coast, Weh Island, Indonesia recorded fish densities of 8 individuals/750 m2 at Pantai sirkui, 9 individuals/750 m2 at Teupin Layeu and 6 individuals/750 m2 at Teluk Pelabuhan (Faculty of Mathematics and Natural Science 2007).
This species was recorded as common in terms of relative abundance in the northern Bismarck Sea, Papua New Guinea (Allen 2009). It is moderately common in Milne Bay Province, Papua New Guinea and in Raja Ampat, Indonesia (Allen 2003, 2003b). It was occasionally found in Calamianes Islands, Philippines (Werner and Allen 2000). It is a ubiquitous species, usually seen over sand (K.D. Clements pers. comm. 2010). 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).
|Habitat and Ecology:||
Acanthurus nigricauda occurs in sandy areas near coral reefs or rocky bottom where it grazes on the biofilm on sandy surfaces. It has low levels of SCFAs (short chain fatty acids) (Clements and Choat 1995). Its diet is dominated by organic detritus and calcareous sediments with very small portions of identifiable algae (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). This species was reported to form spawning aggregations on the Great Barrier Reef (Squire and Samoilys unpub.).
Acanthurus nigricauda may be affected by targeted fishing in some parts of its range.
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:||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., McIlwain, J., Choat, J.H., Abesamis, R., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Acanthurus nigricauda. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 23 May 2013.|
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