''Acanthurus tractus'', the five-band surgeonfish, ocean surgeon, or ocean surgeonfish, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

in the family

Acanthuridae Acanthuridae are the family of surgeonfishes, tangs, and unicornfishes. The family includes about 86 extant species of marine fish living in tropical seas, usually around coral reefs. Many of the species are brightly colored and popular in aq ...

found in the western Atlantic Ocean,

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

the Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

, the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

and the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. Until recently, it was considered a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of ''

Acanthurus bahianus The ocean surgeon or ocean surgeonfish (''Acanthurus bahianus'') is a tropical fish known to live in reefs in the western Atlantic Ocean, especially the Caribbean Sea. It is sometimes marketed fresh as a food item,Baensch, H.A. and H. Debelius ( ...

'', but its status as a separate species was resurrected in 2011.

Taxonomy

''Acanthurus tractus'' was first formally described in 1860 by the Cuban zoologist Felipe Poey with its type locality given as Cuba. This taxon was considered to be a

synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of '' A. bahianus''. In 2011 it was shown that the populations in the North Atlantic differ morphologically and genetically from the South Atlantic populations and the northern Atlantic population is now recognised as the valid and distinct species. The genus '' Acanthurus'' is one of two genera in the tribe Acanthurini which is one of three tribes in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Acanthurinae ''Acanthurinae'' is a subfamily of fish belonging to the family Acanthuridae, including 55 species in four genera. Description Among the species of the genera ''Acanthurus'' and ''Zebrasoma'' there are small anatomical differences: the fir ...

which is one of two subfamilies in the family Acanthuridae.

Etymology

''Acanthurus tractus'' was given the

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''tractus'' which means "streak", Poey did not explain what this alluded to but it may refer to the sinuous, yellow horizontal lines on the body.

Description

''Acanthurus tractus'' grows to a length of about , although is a more typical size. It is a deep-bodied, laterally-compressed oval fish with a steep head profile and large eyes high on the sides of the head. The mouth is small and has protrusible lips. The elongated

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

has nine spines and 23 to 26 soft rays. The elongated anal fin has three spines and 21 to 23 soft rays. The caudal peduncle bears a single depressible spine on either side, and the caudal fin has a concave edge with pointed tips. The colour is somewhat variable, being light beige over sandy substrates and darker brown over rocks. The flanks are sometimes bluish-green, with almost invisible fine vertical striping. Short blue lines radiate from the eye, and the dorsal, anal and caudal fins are edged with blue. The rays of the pectoral fins are often orange, and there is frequently a pale or white ring around the caudal peduncle. This species could be confused with ''

Acanthurus chirurgus ''Acanthurus chirurgus'', commonly called doctorfish or doctorfish tang in English and ''barbero rayado'' or ''cirujano rayado'' in Spanish, is a tropical marine fish common in the Atlantic Ocean. Description Reaching a maximum size of and , ''A ...

'', but that species has about eleven dark vertical stripes on its flanks and its fins are more conspicuously blue. In the Gulf of Mexico, it could be confused with ''

Acanthurus randalli ''Acanthurus randalli'' is a tropical fish found in the western Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its wate ...

'', but that species is rather smaller and has yellower fins. Another similar species is ''

'', but that species has a yellow rather than a blue margin to the dorsal and caudal fins.

Distribution and habitat

''Acanthurus tractus'' is native to the shallow sub-tidal areas of the western Atlantic Ocean, the Caribbean Sea and parts of the Gulf of Mexico. Its range extends from North Carolina to the Bahamas, Bermuda, Florida and

Tuxpan Tuxpan (or Túxpam, fully Túxpam de Rodríguez Cano) is both a municipality and city located in the Mexican state of Veracruz. The population of the city was 78,523 and of the municipality was 134,394 inhabitants, according to the INEGI census o ...

, Mexico, including the Caribbean Sea and the Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico. It is typically found on rocky and coral reefs at depths down to about , but also inhabits rocky shores with patches of sand, and

seagrass meadow A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and ...

Ecology

''Acanthurus tractus'' is diurnal. It feeds by grazing on the algal film that grows on coral and rock substrates. It swallows sand as it feeds, and this is retained in the thin-walled stomach which acts as a gizzard. This fish grows faster than many other species in the genus, and researchers have found that the fish's

longevity The word " longevity" is sometimes used as a synonym for "life expectancy" in demography. However, the term ''longevity'' is sometimes meant to refer only to especially long-lived members of a population, whereas ''life expectancy'' is always d ...

depends on the temperature of the water rather than the size of the fish.

Status

''Acanthurus tractus'' is a common species with a widespread distribution; it faces no known major threats, and is neither targeted by the fishing industry nor by the aquarium trade to any great extent. For these reasons, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has assessed its conservation status as being of

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

References

External links

* {{Taxonbar, from=Q22102567 tractus Fish of the Atlantic Ocean Fish of the Dominican Republic Fish described in 1860 Taxa named by Felipe Poey Fish of Aruba Marine fish of Nicaragua