Acanthonus armatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Ophidiiformes Ophidiidae

Scientific Name: Acanthonus armatus Günther, 1878
Regional Assessments:
Common Name(s):
English Bony-eared Assfish
Acanthonus spinifer Garman, 1899
Taxonomic Source(s): Eschmeyer, W.N. (ed.). 2015. Catalog of Fishes. Updated 3 February 2015. Available at: (Accessed: 5 February 2015).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2015
Date Assessed: 2014-07-08
Assessor(s): Knudsen, S.
Reviewer(s): Weller, S., Santa Cruz, A., Polidoro, B. & Carpenter, K.E.
Facilitator/Compiler(s): Comeros-Raynal, M.
Acanthonus armatus is a deep-sea, circumglobal, benthopelagic fish that occupies abyssal depths. It has been described as common throughout most of its range, and even abundant in the western Atlantic. There do not appear to be any current threats towards this species, and it is of no interest to commercial fishing companies. Although the biology and ecology of this species is poorly understood, it has a widespread distribution and is common to abundant in its natural range. Therefore, it is assessed as Least Concern.

Geographic Range [top]

Range Description:Acanthonus armatus is located in all tropical and subtropical oceans (Nielsen 1990, Nielsen et al. 1999). It has been reported from Carlsberg Ridge (6°22'N 60°12'E) and New Guinea (Fricke 1999). It is also known from Gulf of Mexico, Caribbean Sea, southern India, Philippines, Gulf of Panama and tropical west Africa (Golovan and Pahkorukov 1979). It is associated with depths of between 1,500 and 4,400 m (Nielsen et al. 1999).
Countries occurrence:
Angola; Anguilla; Antigua and Barbuda; Australia; Bahamas; Barbados; Benin; Bermuda; Brazil; British Indian Ocean Territory; Cape Verde; Cayman Islands; China; Colombia; Comoros; Congo, The Democratic Republic of the; Costa Rica; Cuba; Disputed Territory (Paracel Is., Spratly Is.); Dominica; Dominican Republic; Ecuador (Galápagos); Equatorial Guinea; Fiji; French Guiana; French Southern Territories; Gabon; Gambia; Ghana; Grenada; Guadeloupe; Guinea; Guinea-Bissau; Guyana; Haiti; India; Indonesia; Japan; Kenya; Kiribati; Liberia; Madagascar; Malaysia; Maldives; Marshall Islands; Martinique; Mauritania; Mauritius; Mayotte; Micronesia, Federated States of ; Morocco; Mozambique; Nauru; New Caledonia; Nigeria; Oman; Palau; Panama; Papua New Guinea; Peru; Philippines; Portugal (Azores, Madeira); Réunion; Saint Helena, Ascension and Tristan da Cunha (Ascension); Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Vincent and the Grenadines; Sao Tomé and Principe; Senegal; Seychelles; Sierra Leone; Sint Maarten (Dutch part); Solomon Islands; Somalia; South Africa; Spain (Canary Is.); Suriname; Taiwan, Province of China; Tanzania, United Republic of; Togo; Trinidad and Tobago; Turks and Caicos Islands; Tuvalu; Uruguay; Vanuatu; Venezuela, Bolivarian Republic of; Viet Nam; Virgin Islands, British; Virgin Islands, U.S.; Western Sahara; Yemen
FAO Marine Fishing Areas:
Atlantic – western central; Atlantic – eastern central; Atlantic – northeast; Atlantic – northwest; Atlantic – southeast; Atlantic – southwest; Indian Ocean – eastern; Indian Ocean – western; Pacific – southeast; Pacific – western central; Pacific – eastern central; Pacific – northwest
Additional data:
Lower depth limit (metres):4400
Upper depth limit (metres):1500
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Although there have not been any quantitative studies on the population size and trend for Acanthonus armatus, it has been described as "common" (Nielsen et al. 1990). It is reportedly "especially abundant" in the tropical western Atlantic (Nielsen 1990).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Acanthonus armatus is benthopelagic at bathyal and abyssal depths (Yeh et al. 2005). The largest individual has been measures at 38 cm standard length (SL). It is oviparous, with oval pelagic eggs floating in a gelatinous mass (Breder and Rosen 1966). It is noted as having the smallest relative brain size among teleosts, and remarkably large semicircular canals (Nielsen 1994). The diet, fecundity, stages of maturation and early life history traits for this species are poorly understood.

Use and Trade [top]

Use and Trade: Acanthonus armatus is of no interest to commercial fisheries (Nielsen et al. 1999).

Threats [top]

Major Threat(s): Currently, there are no known threats towards this species. It is a very deep-dwelling species where anthropogenic influences are thought to be at a minimum currently, but these deep sea ecosystems are at risk of deteriorating due mainly to dumping of solid wastes, biological harvesting and mineral extraction, and climate change (i.e. global and regional deep-sea circulation disruptions and nutrient stratification and isolation in the water column), all of which will significantly affect the biota of the deep seas (Ramirez-Llodra et al. 2011).


Conservation Actions [top]

Conservation Actions: There are not any specific conservation measures in place for this species. There are numerous marine protected areas (MPAs) in the tropical oceans of the world; however, it remains unknown how effective MPAs are for deep-sea fauna (Howell 2010). Research into all areas of population size and trend, the ecology and early life history traits, as well as potential threats, is suggested for this species.

Classifications [top]

11. Marine Deep Benthic -> 11.1. Marine Deep Benthic - Continental Slope/Bathyl Zone (200-4,000m) -> 11.1.1. Hard Substrate
suitability:Suitable season:resident 
11. Marine Deep Benthic -> 11.1. Marine Deep Benthic - Continental Slope/Bathyl Zone (200-4,000m) -> 11.1.2. Soft Substrate
suitability:Suitable season:resident 
11. Marine Deep Benthic -> 11.2. Marine Deep Benthic - Abyssal Plain (4,000-6,000m)
suitability:Suitable season:resident major importance:Yes

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over part of range
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats

Bibliography [top]

Breder, C.M. and Rosen, D.E. 1966. Modes of reproduction in fishes. T.F.H. Publications, Neptune City, New Jersey.

Fricke, R. 1999. Fishes of the Mascarene Islands (Réunion, Mauritius, Rodriguez): an annotated checklist, with descriptions of new species. Theses Zoology, Königstein, Germany.

Golovan, G. and Pahkorukov, N. 1979. A catch of Acanthonus armatus (Family Brotulidae) off the coast of north-west Africa. Journal of Ichthyology 19(2): 142-143.

Howell, K. 2010. A benthic classification system to aid in the implementation of marine protected area networks in the deep/high seas of the NE Atlantic. Biological Conservation 143: 1041-1056.

IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: (Accessed: 19 November 2015).

Nielsen, J. 1990. Ophidiidae. In: Quero, J, Hureau, J., Karrer, C., Post, A. and Saldena, L. (eds), Checklist of the fishes of the eastern tropical Atlantic, pp. 564-573. CLOFETA, Paris.

Nielsen, J. 1994. Fishes of the World. John Wiley and Sons, New York.

Nielsen, J.G., Cohen, D.M., Markle, D.F. and Robins, C.R. 1999. Ophidiiform fishes of the world (Order Ophidiiformes). An annotated and illustrated catalogue of pearlfishes, cusk-eels, brotulas and other ophidiiform fishes known to date. FAO Fisheries Synopsis, FAO, Rome.

Ramirez-Llodra, E., Tyler, P., Baker, M., Bergstad, O., Clark, M., Eschobar, E., Levin, L.A., Menot, L., Rowden, A.A., Smith, C.R. and Van Dover, C.L. 2011. Man and the Last Great Wilderness: Human Impact on the Deep Sea. Plos One 6(7): e22588.

Yeh, H.-M., Lee, M.-Y. and Shao, K.-T. 2005. Fifteen Taiwanese new records of Ophidiid fishes (Pisces: Ophidiidae) collected from the deep waters by the RV Ocean Researcher I. Journal of the Fisheries Society of Taiwan 32(3): 279-299.

Citation: Knudsen, S. 2015. Acanthonus armatus. The IUCN Red List of Threatened Species 2015: e.T190201A60796787. . Downloaded on 20 May 2018.
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