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Acanthurus triostegus (Linnaeus, 1758)

Convict surgeonfish
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Native range | All suitable habitat | Point map | Year 2100
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Acanthurus triostegus   AquaMaps   Data sources: GBIF OBIS
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Image of Acanthurus triostegus (Convict surgeonfish)
Acanthurus triostegus
Picture by Malaer, P.

Philippines country information

Common names: Bakwak, Convict surgeonfish, Indangan
Occurrence: native
Salinity: marine
Abundance: | Ref:
Importance: commercial | Ref:
Aquaculture: | Ref:
Regulations: | Ref:
Uses: no uses
Comments: Known from San Vicente, N. Luzon (Ref. 58652), Lanuza Bay (Ref 104756) and Leyte Gulf (Ref. 68980). Also Ref. 37792, 48613, 53416, 121724.
National Checklist:
Country Information:
National Fisheries Authority:
Occurrences: Occurrences Point map
Main Ref: Rau, N. and A. Rau, 1980
National Database:

Common names from other countries

Classification / Names Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa

Teleostei (teleosts) > Acanthuriformes (Surgeonfishes) > Acanthuridae (Surgeonfishes, tangs, unicornfishes) > Acanthurinae
Etymology: Acanthurus: Greek, akantha = thorn + Greek, oura = tail (Ref. 45335).
  More on author: Linnaeus.

Environment: milieu / climate zone / depth range / distribution range Ecology

Marine; reef-associated; depth range 0 - 90 m (Ref. 9710), usually 0 - 90 m (Ref. 27115).   Tropical; 26°N - 36°S, 25°E - 85°W (Ref. 57245)

Distribution Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri

Indo-Pacific: throughout the region except for the seas around the Arabian Peninsula. Eastern Pacific: lower Gulf of California to Panama, including the Revillagigedo, Cocos, Clipperton, and Galapagos islands.

Length at first maturity / Size / Weight / Age

Maturity: Lm 8.8  range ? - ? cm
Max length : 27.0 cm TL male/unsexed; (Ref. 3145); common length : 17.0 cm TL male/unsexed; (Ref. 9267)

Short description Morphology | Morphometrics

Dorsal spines (total): 9; Dorsal soft rays (total): 22-26; Anal spines: 3; Anal soft rays: 19 - 22. Body olivaceous gray, with 4 vertical stripes (1 stripe on head across the yellow eye; 1 on caudal peduncle); shading to white ventrally, often with a sharp line of demarcation. Sharp, forward-pointing, erectile spine on each side of caudal peduncle which folds down into a groove. Scales minute. Teeth with denticulations on sides and top. Gill rakers 18-22 in anterior row, 19-24 in posterior row.

Biology     Glossary (e.g. epibenthic)

Adults occur in lagoon and seaward reefs with hard substrate; young abundant in tide pools (Ref. 3145, 48637). Benthopelagic (Ref. 58302). Often feeding near freshwater run-offs where certain algae grow on rocks that are grazed (Ref. 48637). Occasionally form schools; feed on filamentous algae in large aggregations. During spawning, clouds of eggs and sperm are preyed upon by eagle rays which are often present during spawning. Form spawning aggregations (Ref. 27825). Size of metamorphosis from post-larva stage to juvenile is 3.2 cm (Ref. 9267). Utilized as a food fish (Ref. 7364). Minimum depth reported taken from Ref. 27115.

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

Form spawning aggregations (Ref. 27825).

Main reference Upload your references | References | Coordinator : Randall, John E. | Collaborators

Randall, J.E., 1956. A revision of the surgeonfish genus Acanthurus. Pac. Sci. 10(2):159-235. (Ref. 1920)

IUCN Red List Status (Ref. 123251)

  Least Concern (LC) ; Date assessed: 04 May 2010

CITES (Ref. 128078)

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

Threat to humans

  Reports of ciguatera poisoning (Ref. 4690)

Human uses

Fisheries: commercial; aquarium: commercial
FAO(Publication : search) | FishSource | Sea Around Us

More information

FAO areas
Food items
Food consumption
Aquaculture profile
Allele frequencies
Mass conversion
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Gill area


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Internet sources

Estimates based on models

Preferred temperature (Ref. 115969): 23.4 - 28.9, mean 27.6 (based on 2614 cells).
Phylogenetic diversity index (Ref. 82804):  PD50 = 0.5000   [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.02399 (0.01950 - 0.02951), b=2.96 (2.92 - 3.00), in cm Total Length, based on LWR estimates for this species (Ref. 93245).
Trophic level (Ref. 69278):  2.8   ±0.35 se; based on food items.
Resilience (Ref. 120179):  Medium, minimum population doubling time 1.4 - 4.4 years (K=0.35; tm=1-2).
Fishing Vulnerability (Ref. 59153):  Low vulnerability (16 of 100).
Climate Vulnerability (Ref. 125649):  Low to moderate vulnerability (29 of 100).
Price category (Ref. 80766):   Medium.