Acanthurus sohal

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES ACANTHURIDAE

Scientific Name: Acanthurus sohal
Species Authority: (Forsskål, 1775)
Common Name(s):
English Sohal Surgeonfish, Red Sea Surgeonfish, Red Sea Clown Surgeon
Synonym(s):
Acanthurus carinatus Bloch & Schneider, 1801
Aspisurus sohar (Forsskål, 1775)
Chaetodon sohal Forsskål, 1775
Chaetodon sohar (Forsskål, 1775)
Choetodon sohab (Forsskål, 1775)
Ctenodon ruppelii Swainson, 1839
Taxonomic Notes: Acanthurus sohal is closely related to the Indo-Pacific species Acanthurus lineatus (Alwany et al. 2005).

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., McIlwain, J., Abesamis, R., Clements, K.D., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.
Reviewer(s): McClenachan, L., Edgar, G. & Kulbicki, M.
Justification:
Acanthurus sohal inhabits the outer edge of fringing reefs where exposed to surge in depths from 0-50m. It is a targeted food fish and a component of the marine aquarium trade. FAO landings data from Saudi Arabia indicate declines from a peak of 62 tonnes in 2005 to a low of 18 tonnes in 2007, however, these declines do not reach the thresholds for a threatened category. A. sohal is common and is the most abundant acanthurid throughout its range. It is therefore listed as Least Concern. This species is found in a number of marine protected areas in parts of its distribution. We recommend continued monitoring of the population status and harvest levels of this species.

Geographic Range [top]

Range Description:Acanthurus sohal is found from the Red Sea, around the Arabian Peninsula to the Persian Gulf.  It is not found in the Seychelles where the sister species A. lineatus occurs (J.H. Choat pers. comm. 2010).
Countries:
Native:
Bahrain; Djibouti; Egypt; Eritrea; Iran, Islamic Republic of; Iraq; Israel; Jordan; Kuwait; Oman; Qatar; Saudi Arabia; Somalia; Sudan; United Arab Emirates; Yemen
FAO Marine Fishing Areas:
Native:
Indian Ocean – western
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: FAO capture production from Saudi Arabia recorded 18 tonnes in 2000, increasing to 56 tonnes in 2003 and a peak in 2005 with 62 tonnes, it has decreased to 17 tonnes in 2006 and 18 tonnes in 2007. There are no capture production records for this species prior to 2000.

In Ras Mohammed National Park, species abundance was recorded at 9.3 to 43 fish per 300 m2 (Alwany et al. 2005). It is very abundant in shallow water. Abundance estimates in the southern Arabian gulf (Musandam) recorded 18 individuals per 1,000 m2. In northern Oman (Daymaniyat Islands)  46.7 individuals per 1,000 m2. In the Red Sea, abundance estimates of 267.7 individuals per 1,000 m2 were recorded by A. Ayling (J.H. Choat pers. comm. 2010). At two sites in Dhofar,  2 individuals/250 m2 were recorded. It is occasional along the Oman coast of the Arabian Seaash (J. McIlwain unpub. data). It is the most abundant Acanthurid in this region (J.H. Choat pers. comm. 2010).

In the Nabq Managed Resource Protected Area, South Sinai, Egyptian Red Sea, mean abundances for A. sohal were generally higher in the no-take zones (NTZ) than in the take zones (TZ) across 1 and 3 m, however there was no significant difference between zones in 10 m depth (Ashworth and Ormond 2005).
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: Acanthurus sohal inhabits the outer edge of fringing reefs where exposed to surge. It is strongly territorial and highly aggressive. It displays aggression by swimming rapidly towards the intruder, turning at the last moment or brushing alongside the other fish (Alwany et al. 2005). This aggressive behaviour ultimately affects not only the distribution of algae but also of sessile epibenthic invertebrates (Vine 1974, Randall 1983). 

Acanthurus sohal
and Zebrasoma xanthurum cohabit fringing reefs in Oman and feed on epilithic algal species (Mill 2007). It is herbivorous and usually swims solitarily around its territory (Alwany et al. 2005). It feeds on benthic algae (Sommer et al. 1996). Schooling enables A. sohal to sometimes feed on the territories of other fishes (Vine 1974). A study by Alwany et al. (2005) show that this species spends considerable time (51.3%) swimming and patrolling the borders of its territory. Feeding occupied only 33.7%. It also spends less time sheltering (6%), usually outside the territory. Short sheltering time and feeding time indicate that the primary function of the territory is to defend food resources (Warner and Hoffman 1980, Tricas 1989a).
 
From a small sample in northern Oman (n=10) the maximum age for 32.3 cm (FL) specimen was recorded at 11 years. This is short lifespan for an acanthurid this size and reflects the influence of the high productivity upwelling coastal environment. One specimen sampled in southern Oman (Al Halanyat) was 32 cm at 26 years (J.H. Choat and J. McIlwain unpub. data).

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).

Systems: Marine

Use and Trade [top]

Use and Trade: Acanthurus sohal is a targeted food fish. It is also a component of the aquarium trade (Global Marine Aquarium Database accessed 19 March 2010). Online prices range from $112.98-$239.99  per fish (L. Rocha pers. comm. 2010).

Threats [top]

Major Threat(s): There have been localized population declines recorded from Saudi Arabia.

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.

Bibliography [top]

Alwany, M., Thaler, E. and Stachowitsch, M. 2005. Territorial behaviour of Acanthurus sohal and Plectroglyphidodon leucozona on the fringing Egyptian Red Sea reefs. Environmental Biology of Fishes 72: 321-334.

Ashworth, J.S. and Ormond, R.F.G. 2005. Effects of fishing pressure and trophic group on abundance and spillover across boundaries of a no-take zone. Biological Conservation 121: 333-344.

Comeros-Raynal, M.T., Choat, J.H., Polidoro, B., Clements, K.D., Abesamis, R., Craig, M.T., Lazuardi, M.E., McIlwain, J., Muljadi, A., Myers, R.F., et al.. 2012. The likelihood of extinction of iconic and dominant components of coral reefs: the parrotfishes and surgeonfishes. PLoS ONE http://dx.plos.org/10.1371/journal.pone.0039825.

Global Marine Aquarium Database. 2010. Species Trade Details. Available at: http://www.unep-wcmc.org/GMAD/species.cfm. (Accessed: March 19).

IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.2). Available at: http://www.iucnredlist.org. (Accessed: 17 October 2012).

Mill, A. 2007. Stable Isotope Data as Reef Food-Web Descriptors in a Dynamic Tropical Environment. School of Marine Science and Technology, University of Newcastle.

Randall, J.E. 1983. Red Sea Reef Fishes. IMMEL Publishing, London.

Randall, J.E. 2001a. Surgeonfishes of the world. Mutual Publishing and Bishop Museum Press, Hawai'i, Honolulu, Hawaii.

Reeson, P.H. 1983. The biology, ecology and bionomics of the surgeonfishes, Acanthuridae. In: J.L. Munro (ed.), Caribbean coral reef fishery resources, pp. 178-190.

Sommer, C., Schneider, W. and Poutiers, J.-M. 1996. FAO species identification field guide for fishery purposes. The living marine resources of Somalia. FAO, Rome.

Tricas, T.C. 1989a. Determinants of feeding territory size in the corallivorous butterflyfish, Chaetodon multicinctus. Animal Behavior 37: 830-841.

Vine, P.J. 1974. Effects of algal grazing and aggressive behavior of the fishes Pomacentrus lividus and Acanthurus sohal on coral-reef ecology. Marine Biology 24: 131-136.

Warner, R.R. and Hoffman, S.G. 1980. Population density and the economics of territorial defense in a coral reef fish. Ecology 61: 772-780.


Citation: Choat, J.H., McIlwain, J., Abesamis, R., Clements, K.D., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Acanthurus sohal. In: The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 21 December 2014.
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