Thalassoma bifasciatum
Bluehead
Collection Details
Specimens
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Taxonomic Hierarchy
Actinopterygii (Ray-finned Fishes)
Perciformes (Perciformes, Also Called the Acanthopteri)
Labridae (Wrasses)
Thalassoma
Thalassoma bifasciatum (Bluehead)
Description
This species account was compiled from
Composite (multiple sources) (McEachran, J.D. and J.D. Fechhelm. Fishes of the Gulf of Mexico. University of Texas Press, Austin.)
and processed using AI-assisted text extraction.
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Characters
Moderately elongate, with a moderately pointed snout, a complete lateral line, and a truncate to lunate caudal fin. Upper and lower profiles of body are nearly symmetrical. Mouth has a prominent downward-projecting flap extending from lower lip and covering posterior section of mouth. Jaw teeth are arranged in a single row and increase in size anteriorly, with those near symphysis projecting anteriorly. Corner of mouth lacks canine tooth. Preopercular margin is membranous. Gill membranes are broadly joined and united with isthmus. Gill rakers on first arch are very short and number 17 to 21. Measurements are expressed as percent of SL: head length 29%–33%, snout length 7%– 8%, eye diameter 5%– 6%, upper jaw length 6%–7%, pectoral fin length 21%–26%, body depth 23%–29%. Pectoral fin has 14 or 15 rays. Dorsal fin has eight spines and 12 or 13 rays, with membrane behind spines elongated into filaments. Anal fin has three spines and 10 or 11 rays. Caudal fin is slightly truncate to slightly rounded in juveniles and lunate in adults. Body and base of caudal fin are covered with scales, but head is naked. Lateral line is strongly arched posteriorly and consists of 26 pored scales.
Color in life is yellow dorsally and white ventrally, with a broad, dusky greenish stripe or series of square greenish blotches on midflank and a dark spot on anterior part of dorsal fin. Large males have a blue head and a green body, and the two colors are separated by two black bands that are in turn separated by a light blue band.
Distribution
In the western Atlantic it occurs at shallow depths from eastern Florida and Bermuda to northern South America, including the Gulf of Mexico, the Bahamas, and the Greater and Lesser Antilles.
Found throughout the Gulf of Mexico
Habitat Associations
Associated with coral reefs. Forms large aggregations over shallow reefs and reef flats.
Coral reefs
Biology
Food consists of zooplankton, benthic invertebrates, and ectoparasites of other fishes.
Maximum known size is 180 mm TL.
Inhabits reef areas, inshore bays and seagrass beds. Feeds mainly on zooplankton and small benthic animals, but may also feed on ectoparasites of other fishes (Ref. 9626). Spawn at midday throughout the year (Ref. 26938). A protogynous hermaphrodite (Ref. 55367). Generally of no interest to fisheries because of its small average size (Ref. 5217).
Reproductive mode: protogyny; fertilization: external. A diandric species (Ref. 55367). Sex reversal is completed in more than 3-4 weeks (Ref. 34185, 34257). Length at sex change = 8.3 cm TL, forms leks during breeding (Ref. 55367).
IUCN Red List Status: Least Concern (LC), assessed 2008-04-12. Resilience: High (k=0.7; tmax=3).
Commercial or Environmental Importance
Fisheries: commercial; aquarium: commercial.
References
Longley and Hildebrand 1941
Feddern 1965
Randall and Böhlke 1965
Böhlke and Chaplin 1968
Randall 1968a, 1996
Bright and Cashman 1974
Hastings and Bortone 1976
Sonnier et al. 1976
Hoese and Moore 1977, 1998
Castro-Aguirre and Márquez-Espinoza 1981
Robins and Ray 1986
Boschung 1992
Schaldach et al. 1997
Smith 1997
Smith-Vaniz et al. 1999
Westneat 2002a
Randall, J.E. (1967) Food habits of reef fishes of the West Indies. Stud. Trop. Oceanogr. Miami 5:665-847.
Bardach, J.E. (1959) The summer standing crop of fish on a shallow Bermuda Reef. Limnol. Oceanogr. 4:77-85.
Robins, C.R. and G.C. Ray (1986) A field guide to Atlantic coast fishes of North America. Houghton Mifflin Company, Boston, U.S.A. 354 p.
Lieske, E. and R. Myers (1994) Collins Pocket Guide. Coral reef fishes. Indo-Pacific & Caribbean including the Red Sea. Haper Collins Publishers, 400 p.
Randall, J.E. (1996) Caribbean reef fishes. Third Edition - revised and enlarged. T.F.H. Publications, Inc. Ltd., Hong Kong. 3nd ed. 368 p.
Claro, R. (1994) Características generales de la ictiofauna. p. 55-70. In R. Claro (ed.) Ecología de los peces marinos de Cuba. Instituto de Oceanología Academia de Ciencias de Cuba and Centro de Investigaciones de Quintana Roo.
García-Cagide, A., R. Claro and B.V. Koshelev (1994) Reproducción. p. 187-262. In R. Claro (ed.) Ecología de los peces marinos de Cuba. Inst. Oceanol. Acad. Cienc. Cuba. and Cen. Invest. Quintana Roo (CIQRO) México.
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