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Acanthurus blochii

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES ACANTHURIDAE

Scientific Name: Acanthurus blochii
Species Authority: Valenciennes, 1835
Common Name(s):
English Ringtail Surgeonfish, Blue-banded Pualu, Dark Surgeon, Tailring Surgeonfish, Whitetail Lancet

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2010-05-03
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): Davidson, L., Edgar, G. & Kulbicki, M.
Justification:
Acanthurus blochii is widespread and common in parts of its range. It is a targeted food fish in parts of its distribution (Guam, Saipan and the Philippines) and is harvested for the aquarium trade. There are localized declines observed in the Philippines but there is no evidence of global population declines due to fishing. It occurs in a number of marine protected areas and is therefore listed as Least Concern.

Geographic Range [top]

Range Description: Acanthurus blochii is found from the coast of East Africa to the Hawaiian Islands and the islands of French Polynesia, northwards to the Ryukyu Islands, Japan, southwards to the Great Barrier Reef and Lord Howe Island, Australia (Randall 2001). It is also reported from Rowley Shoals, Scott Reef and Ashmore Reef (Allen and Russell 1986) and Christmas Island (J.H. Choat pers. comm. 2010). Records from the New South Wales coast may be based on misidentification of A. dussumieri (J.H. Choat and B. Russell pers. comm. 2010).
Countries:
Native:
American Samoa (American Samoa); Australia; British Indian Ocean Territory; Brunei Darussalam; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Disputed Territory (Spratly Is.); Djibouti; Fiji; French Polynesia; French Southern Territories (Mozambique Channel Is.); Guam; Indonesia; Japan; Kenya; Kiribati (Gilbert Is., Kiribati Line Is., Phoenix Is.); Madagascar; Malaysia; Marshall Islands; Mauritius (Mauritius (main island), Rodrigues); Mayotte; Micronesia, Federated States of ; Mozambique; Nauru; New Caledonia; Niue; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Réunion; Samoa; Seychelles; Solomon Islands; Somalia; South Africa; 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:
Native:
Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Acanthurus blochii was recorded as occasional in terms of relative abundance in Calamianes Islands, Philippines and the northern Bismarck Sea, Papua New Guinea (Werner and Allen 2000, Allen 2009). It was recorded as common in Milne Bay, Papua New Guinea (Allen 2003). It is moderately common at Raja Ampat (Allen 2003b). It is common in the American Samoa National Park (National Park of Samoa Checklist of Fishes, accessed 21 April 2010). It is one of the most common fishes recorded in the Bar Reef Marine Sanctuary (BRMS), northwestern Sri Lanka. It was found to be most abundant in shallow reef flat and structured sandstone reef habitats (Ohman et al. 1997).

Density and biomass did not change significantly in marine reserves censused in New Caledonia before and after protection (Wantiez et al. 1997).

                                                Before                                       After
Density (10-2 fish m-2)           1.26 (0.50)                               1.36 (0.39)
Biomass (g m-2)                    1.65 (0.33)                               2.21 (0.65)

A. blochii accounts for 2% and 1% of the Acanthurid fishery in Guam (Division of Aquatic and Wildlife Resources unpub. data) and Saipan (P. Houk unpub. data) respectively, but shows no signs of decline. It was not observed from the fishery in Ponpei (Rhodes et al. 2008). Average catch is 2,900 kg/year in Hawaii (Division of Aquatic Resources unpub. data). This species is collected as an aquarium fish in West Hawaii. The total number of individuals caught from FY 2005-2009 was 134 with a total value of $182 (Walsh et al. 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: Acanthurus blochii occurs on shallow coral reef (Randall 2001). It is occasionally observed in seagrass beds in Ryukyu Islands (Nakamura amd Tsuchiya 2009). Juveniles settle in coral rubble at Ishigaki Island, Japan (Nakamura et al. 2009). It feeds on detritus and sedimentary material (Choat et al. 2004).  It is classified as a grazer/detritivore (J.H. Choat and D.R. Bellwood pers. obs. in Green and Bellwood 2009). Maximum age recorded was 35 years (Choat and Robertson 2002). The sexes are separate among the acanthurids and there is no evidence of sexual dimorphism (Reeson 1983).
Systems: Marine

Use and Trade [top]

Use and Trade: Acanthurus blochii is one of the most important species captured in islands of the southwest lagoon of New Caledonia (Wantiez et al. 1997). It is also a component of the aquarium trade (juveniles) (GMAD). It sells for $29.99-$99.95 online (L. Rocha pers. comm. 2010).

In the Philippines, it is one of the most targeted Acanthurids. There have been localized declines observed in central Philippines (B. Stockwell pers. comm. 2010).

Threats [top]

Major Threat(s): Acanthurus blochii is a targeted food fish in parts of its range. There have been localized declines due to fishing in the Philippines.

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 several marine protected areas in parts of its range.

Citation: Choat, J.H., Abesamis, R., Clements, K.D., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Acanthurus blochii. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 September 2014.
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