|Scientific Name:||Acanthurus coeruleus|
|Species Authority:||Bloch & Schneider, 1801|
Acanthurus brevis Poey, 1860
Acanthurus broussonnetii Desmarest, 1823
Acanthurus caeruleus (Bloch & Schneider, 1801)
Acanthurus coerulus Bloch & Schneider, 1801
Acanthurus heliodes (Barbour, 1905)
Acanthurus nigricans (non Linnaeus, 1758)
Acanthurus violaceus Castelnau, 1855
Acronurus caeruleatus Poey, 1875
Hepatus caeruleus (Bloch & Schneider, 1801)
Hepatus pawnee Breder, 1927
Teuthis coeruleus (Bloch & Schneider, 1801)
Teuthis helioides Barbour, 1905
|Taxonomic Notes:||There was a significant level of genetic structure observed between North and South Atlantic populations, suggesting limited dispersal across the Amazon barrier (Rocha et al. 2002).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Choat, J.H., Myers, R., Rocha, L.A., Abesamis, R., Clements, K.D., McIlwain, J., Nanola, C., Russell, B. & Stockwell, B.|
|Reviewer/s:||Floeter, S., Edgar, G., Davidson, L. & Kulbicki, M.|
Acanthurus coeruleus is widely distributed in the Atlantic. It is common and abundant throughout its range. It is targeted in some areas and there have been localized declines from harvesting, however it is found in a number of marine reserves in parts of its range. It is therefore listed as Least Concern.
|Range Description:||Acanthurus coeruleus is found from South Carolina, USA (juveniles to New York), Bermuda, southwards to Sao Paulo, Brazil (L. Rocha pers. comm. 2010). It is also reported from Ascension and St. Helena Island.|
Native:Anguilla; Antigua and Barbuda; Aruba; Bahamas; Barbados; Belize; Bermuda; Brazil (Trindade); Cayman Islands; Colombia; Costa Rica; Cuba; Dominica; Dominican Republic; French Guiana; Grenada; Guadeloupe; Guatemala; Guyana; Haiti; Honduras; Jamaica; Martinique; Mexico; Montserrat; Netherlands Antilles; Nicaragua; Panama; Puerto Rico; Saint Barthélemy; Saint Helena, Ascension and Tristan da Cunha (Ascension); Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Vincent and the Grenadines; Suriname; Trinidad and Tobago; Turks and Caicos Islands; United States; Venezuela; Virgin Islands, British; Virgin Islands, U.S.
|FAO Marine Fishing Areas:||
Atlantic – northwest; Atlantic – southeast; Atlantic – southwest; Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Acanthurus coeruleus is rare in the Gulf of Mexico and is not common north of Florida. Acanthurus coeruleus was the most abundant species observed in traps from the U.S. Virgin Islands (Garrison et al. 2004). It is common and abundant throughout its range (L. Rocha pers. comm. 2010). There were order of magnitude differences in biomass among six Caribbean islands studied on which fishing pressure ranged from non existent in Bonaire, increasing through Saba, Puerto Rico, St. Lucia and Dominica and reaching very high intensities in Jamaica, with biomass declining as fishing intensity increased (Hawkins and Roberts 2004). Densities were recorded at (0.07 ind m-2) from Abrolhos Bank eastern Brazil. It showed higher densities within the no-take area of Timbebas (Francino-Filho et al. 2009).|
|Habitat and Ecology:||
Acanthurus coeruleus is found on coral reefs, rocky habitats and grassy areas in depths from 1 to 60 m. It grazes on a wide variety of benthic algae, occasionally on seagrass. It is sometimes seen in feeding aggregations with Acanthurus bahianus and/or A. chirurgus. In the Abrolhos Bank, all roving herbivorous species ingest large amounts of detritus with the exception of A. coeruleus. It is mainly a fleshy algae consumer (Ferreira and Goncalves 2006). The digestive tract contains little sand or inorganic material (Randall 2002a). It aggregates with other surgeonfishes (A. bahianus, A. tractus and A. chirurgus) to raid algae patches guarded by damselfishes.
Juveniles of this species are solitary and territorial (Bell and Kramer 2000) while adults commonly form mixed-species schools (Foster 1985) to facilitate access to defended high quality algal resources in damselfish territories (Robertson et al. 1976, Foster 1985). Schooling occurs primarily in adults; small juveniles never participate in large, dense schools. The proportion of adults that were schooling increased from the back reef to the reef crest to the spurs and grooves zone (Lawson et al. 1999).
A. coeruleus adults are consistently either territorial or non-territorial, with territorial individuals found in schools and wandering. Territorial adults engage in aggressive interactions with conspecific and congeners. Fish in the territorial mode restrict activity to a small area overlapping the territories of other tangs. Non-territorial fish form schools and wander (Morgan and Kramer 2004).
A. coeruleus displays the highly characterized pattern of asymptotic growth. Terminal size was reached at around age 4, and most of the growth occurred within the first 10% of the lifespan, and approximately 85% of somatic size was attained within the first year. The mean maximum age fluctuated from 8 years in Belize to 37 years in Bermuda with a maximum longevity of 43 years in Bermuda (Mutz 2006).
A study by Choat and Robertson (2002) show the following maximum age estimates from different locations of this species' range:
Ascension Island - 37 years
San Blas, Panama - 16 years
Lee Stocking Island, Bahamas - 27 years
In upwelling areas in Isla Margarita, Venezuela, it achieves 320 mm (SL), very rapid non-asymptotic growth the same as A. chirurgus (Robertson et al. 2005b, Choat and Robertson 2002a).
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). It appears to normally mature at ~ 13 cm (FL) (Reeson 1983). This species was observed to form late afternoon resident spawning aggregations of 6,000-7,000 individuals, possibly year-round, during a 12-21 day period centered between the full and new moon of each month off southwestern Puerto Rico. This species also pair spawns. The pair spawning male holds a benthic territory and develops an ephemeral 'white-faced' color phase (Domeier and Colin 1997).
The pelagic larval stage duration ranges from 46 to 57 days (B. Victor in Rocha et al. 2002), it then settles on reefs when 26.7 mm (Robertson 1992). After settlement, juveniles have a distinct yellow coloration. Juveniles occur primarily on the reef crest, spurs, and a transition zone between the reef crest and reef flat (Bell and Kramer 2000). A study by Lawson et al. (1999) showed that this species exhibits ontogenetic habitat shifts. Newly settled blue tangs occur in the reef crest and spurs and grooves, but larger juveniles are more common in the back reef, while adults are evenly distributed across zones.
At Fernando de Noronha Archipelago in the southwestern Atlantic, juveniles hold cleaning stations together with the Doctorfish (Acanthurus chirurgus) and Sergeant Major (Abudefduf saxatilis) and graze algae as well as pick molted skin and parasites from Green Turtles (Chelonia mydas). This behaviour is preceded by a characteristic inspection usually followed by feeding nips on the turtles' skin (head, limbs, and tail), as well as on the carapace. The most inspected and cleaned body parts are the flippers (Sazima et al. 2004).
Acanthurus coeruleus is a targeted food fish in parts of its range. It is heavily fished in some areas (Haiti and Jamaica).
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. Its distribution overlaps several marine protected areas in parts of its range.|
|Citation:||Choat, J.H., Myers, R., Rocha, L.A., Abesamis, R., Clements, K.D., McIlwain, J., Nanola, C., Russell, B. & Stockwell, B. 2012. Acanthurus coeruleus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 25 May 2013.|
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