The yellowhead wrasse (''Halichoeres garnoti'') is a
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
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 ...
belonging to
wrasse
The wrasses are a family, Labridae, of marine fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 81 genera, which are divided into 9 subgroups or tribes.
They are typically small, most of them le ...
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
native to shallow tropical waters in the Caribbean Sea and western Atlantic Ocean.
Description
![Juvenile Yellowhead wrasse (Halichoeres garnoti)](https://upload.wikimedia.org/wikipedia/commons/9/97/Juvenile_Yellowhead_wrasse_%28Halichoeres_garnoti%29.jpg)
The yellowhead wrasse is a small sized fish that can reach a maximum length of 19 cm. Both its sex and appearance change during its life and the colouring at each stage is rather variable.
The body is thin, relatively lengthened and its mouth is terminal.
As a juvenile, it is mainly yellow with a lateral, bright-blue stripe.
In its initial phase, while it is female, it has a dark-colored back, sometimes with bluish shadings, and a yellow underside. Two short wavy dark lines radiate from the hind edge of each eye with dark spots on its front head.
Later, as an adult male, the head and front part of the body are yellow, the hind half of the body is silvery grey and a vertical black blue bar and a broad black blue stripe occur along the border of the dorsal fin. From this dark blue line, three longitudinal lines of gradient colors are visible, they are successively green, blue (this latter continues throughout the ventral part of the fish) then pink to mauve color. It still has the characteristic dark, wavy lines near the eye with the black spots.
Distribution and habitat
The yellowhead wrasse is widespread throughout the tropical and subtropical waters of the western
Atlantic Ocean
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 water surface area. It is known to separate the " Old World" of Africa, Europe ...
, 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 ...
south to the north coast of
Venezuela
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
.
The yellowhead wrasse is common on coral and sandy reefs and among rocks at depths down to about . It likes places with many small cavities where it can hide in case of danger.
Biology
The yellowhead wrasse is a
predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
that feeds mainly on small
invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
such as
crustaceans
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
,
molluscs
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant taxon, extant species of molluscs are recognized. The number of fossil sp ...
,
worms Worms may refer to:
*Worm, an invertebrate animal with a tube-like body and no limbs
Places
*Worms, Germany, a city
**Worms (electoral district)
*Worms, Nebraska, U.S.
*Worms im Veltlintal, the German name for Bormio, Italy
Arts and entertainme ...
and
echinoderms
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea li ...
captured on the substrate or in the sand. Its prominent teeth help it to grasp crustaceans and to lever prey items off rocks.
During its juvenile phase, this wrasse can behave like a
cleaner fish
Cleaner fish are fish that show a specialist feeding strategy by providing a service to other species, referred to as clients, by removing dead skin, ectoparasites, and infected tissue from the surface or gill chambers. This example of cleaning ...
.
Like many other wrasses, the yellowhead wrasse is a
protogynous hermaphrodite
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...
, starting life as a female and later becoming a male, changing sex when it is about long. Mature males are territorial during the breeding season and gather in a
lek
Lek or LEK may refer to:
* Lek mating, mating in a lek, a type of animal territory in which males of a species gather
* Albanian lek, the currency of Albania
* Lek (magazine), a Norwegian softcore pornographic magazine
* Lek (pharmaceutical comp ...
. A daily migration from feeding grounds to spawning sites occurs, and large males tend to monopolize mates.
Status and threats
It is targeted for the aquarium trade, but it is not thought to be a major threat. This species is listed as least Concern (LC) on the
UICN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...
.
[Rocha, L. & Craig, M. 2010. Halichoeres garnoti. The IUCN Red List of Threatened Species. Version 2015.2. www.iucnredlist.org. Downloaded on 20 August 2015.]
References
External links
*
{{Taxonbar, from=Q3752250
Yellowhead wrasse
Taxa named by Achille Valenciennes
Fish described in 1839
Fish of the Atlantic Ocean