|Scientific Name:||Acanthurus gahhm|
|Species Authority:||(Forsskål, 1775)|
Acanthurus nigricans (Linnaeus, 1758)
Acanthurus nigricauda (Duncker & Mohr, 1929)
Chaetodon nigrofuscus subspecies gahhm Forsskål, 1775
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Abesamis, R., Choat, J.H., Clements, K.D., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B.|
|Reviewer/s:||Raynal, M. & Polidoro, B.|
|Contributor/s:||Ram, M., Beresford, A., Collen, B., Richman, N. & Chenery, A.|
Acanthurus gahhm is endemic to the Red Sea, Gulf of Aden and Socotra. It is occasionally encountered over hard reef substrata in Jeddah and Dubba, Saudi Arabia, but may be locally abundant in appropriate habitat (e.g. lagoons). This species inhabits a variety of habitats including open sand and rubble bottoms in lagoons and seaward reefs. It is a component of the marine aquarium trade and is well represented in fish markets in parts of its range, however, there are no indications at the present time of detrimental effects of harvesting to the population. Although this species shows varying degrees of habitat preference and utilization of coral reefs, it inhabits areas where coral reef degradation and loss is underway. Additional research is needed to understand the long-term effects of coral reef habitat loss and degradation on these species populations. Its distribution overlaps with some marine protected areas in parts of its range. It is therefore listed as Least Concern.
|Range Description:||Acanthurus gahhm is endemic to the Red Sea, Gulf of Aden and Socotra (Randall 2001a). Records from other areas (central west Pacific) are probably misidentifications of A. nigricauda (L. Rocha pers comm. 2010).|
Native:Djibouti; Egypt; Eritrea; Israel; Jordan; Saudi Arabia; Somalia; Sudan; Yemen
|FAO Marine Fishing Areas:||
Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Underwater fish visual surveys in Jeddah and Dubba on the east coast of the Red Sea recorded Acanthurus gahhm as occasional with a maximum of 0.1 individuals per 300 m2 (A. Ayling pers comm. 2010). However, the surveys conducted in Jeddah and Dubba, Saudi Arabia, were carried out on hard reef substrate - as this species inhabits sand/lagoonal areas, it is inferred that A. gahhm will be more abundant in lagoons. This species is well represented in the Jeddah fish market (J.H. Choat pers comm. 2010).|
|Habitat and Ecology:||Acanthurus gahhm, has a depth range of 5-50 m and is usually found in tropical climates over open sand and rubble bottoms in lagoons or at the base of seaward reefs (Kuiter and Debelius 2001). It is also often found in large groups in open areas near coral or rock, and in small groups which sometimes join to form large loose aggregations.|
Acanthurus gahhm is associated with coral reef habitats. Urban growth, coastal land reclamation, fisheries expansions and water pollution combined with Crown of Thorns (COTS) outbreaks are placing increasing pressure on the coral reefs of the Red Sea and Gulf of Aden (Kotb et al. 2004). It is predicted that pressures on the reefs of the Red Sea and Gulf of Aden will increase over the next 8 years due to major development for mass tourism and industrialization, over exploitation, destructive fishing in poorly managed areas and COTS outbreaks (Kotb et al. 2004).
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 Acanthurus gahhm. However, the distribution of this species overlaps with a number of marine protected areas in its range of distribution. There has been some success in establishing MPA's in the Red Sea, but there is little or no effective regional MPA network, and most of the MPAs have ineffective management (Kotb et al. 2004).|
|Citation:||Abesamis, R., Choat, J.H., Clements, K.D., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Acanthurus gahhm. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 11 December 2013.|
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