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 less than long, although the largest, the
humphead wrasse, can measure up to . They are efficient carnivores, feeding on a wide range of small
invertebrates. Many smaller wrasses follow the feeding trails of larger fish, picking up invertebrates disturbed by their passing.
Juveniles of some representatives of the genera ''
Bodianus'', ''
Epibulus'', ''
Cirrhilabrus'', ''
Oxycheilinus'', and ''
Paracheilinus'' hide among the tentacles of the free-living
mushroom corals & ''
Heliofungia actiniformis''.
The word "wrasse" comes from the
Cornish word ''wragh'', a
lenited form of ''gwragh'', meaning an old woman or hag, via
Cornish dialect ''wrath''. It is related to the
Welsh ''gwrach'' and
Breton
Breton most often refers to:
*anything associated with Brittany, and generally
** Breton people
** Breton language, a Southwestern Brittonic Celtic language of the Indo-European language family, spoken in Brittany
** Breton (horse), a breed
**Ga ...
''gwrac'h''.
Distribution
Most wrasses inhabit the tropical and subtropical waters of the
Atlantic,
Indian, and
Pacific Oceans, though some species live in temperate waters: the
Ballan wrasse is found as far north as Norway. Wrasses are usually found in shallow-water habitats such as
coral reefs and rocky shores, where they live close to the substrate.
Anatomy
Wrasses have
protractile mouths, usually with separate jaw teeth that jut outwards.
[
] Many species can be readily recognized by their thick lips, the inside of which is sometimes curiously folded, a peculiarity which gave rise to the German name of "lip-fishes" (''Lippfische''),
and the Dutch name of ''lipvissen''. The
dorsal fin has eight to 21 spines and six to 21
soft rays, usually running most of the length of the back. Wrasses are
sexually dimorphic. Many species are capable of
changing sex. Juveniles are a mix of males and females (known as initial-phase individuals), but the largest adults become territory-holding (terminal-phase) males.
The wrasses have become a primary study species in fish-feeding
biomechanics due to their jaw structures. The nasal and
mandibular bones are connected at their posterior ends to the rigid
neurocranium, and the superior and inferior articulations of the
maxilla are joined to the anterior tips of these two bones, respectively, creating a loop of four rigid bones connected by moving joints. This "
four-bar linkage" has the property of allowing numerous arrangements to achieve a given mechanical result (fast
jaw protrusion
Most bony fishes have two sets of jaws made mainly of bone. The primary oral jaws open and close the mouth, and a second set of pharyngeal jaws are positioned at the back of the throat. The oral jaws are used to capture and manipulate prey by b ...
or a forceful bite), thus decoupling
morphology from function. The actual morphology of wrasses reflects this, with many lineages displaying different jaw morphology that results in the same functional output in a similar or identical ecological niche.
Reproductive behavior
Most labrids are
protogynous hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...
s within a
haremic mating system.
[
][
] A good example of this reproductive behavior is seen in the
California sheephead. Hermaphroditism allows for complex mating systems. Labroids exhibit three different mating systems:
polygynous
Polygyny (; from Neoclassical Greek πολυγυνία (); ) is the most common and accepted form of polygamy around the world, entailing the marriage of a man with several women.
Incidence
Polygyny is more widespread in Africa than in any ...
,
lek-like, and
promiscuous.
[
] Group spawning and pair spawning occur within mating systems. The type of spawning that occurs depends on male body size.
Labroids typically exhibit
broadcast spawning
Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic ani ...
, releasing high numbers of
planktonic eggs, which are broadcast by
tidal currents; adult labroids have no interaction with offspring.
[
] Wrasses of a particular subgroup of the family Labridae, Labrini, do not exhibit broadcast spawning.
Sex change in wrasses is generally female-to-male, but experimental conditions have allowed for male-to-female sex change. Placing two male ''Labroides dimidiatus'' wrasses in the same tank results in the smaller of the two becoming female again.
[
] Additionally, while the individual to change sex is generally the largest female,
[
] evidence also exists of the largest female instead "choosing" to remain female in situations in which she can maximize her evolutionary fitness by refraining from changing sex.
[
]
Broodcare behavior of the tribe
The subgroup Labrini arose from a basal split within family Labridae during the
Eocene period.
Subgroup Labrini is composed of eight genera, wherein 15 of 23 species exhibit broodcare behavior,
which ranges from simple to complex parental care of spawn; males build algae nests or crude cavities, ventilate eggs, and defend nests against
conspecific males and predators.
In species that express this behavior, eggs cannot survive without parental care.
[
] Species of ''
Symphodus
''Symphodus'' is a genus of wrasses native to the eastern Atlantic Ocean and the Mediterranean Sea.
Species
The currently recognized species in this genus are:
* '' Symphodus bailloni'' (Valenciennes, 1839) (Baillon's wrasse)
* '' Symphodus caer ...
,
Centrolabrus
''Centrolabrus'' is a small genus of 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 tr ...
'', and ''
Labrus'' genera exhibit broodcare behavior.
Cleaner wrasse
Cleaner wrasses are the best-known of the
cleaner fish. They live in a
cleaning symbiosis
Cleaning symbiosis is a mutually beneficial association between individuals of two species, where one (the cleaner) removes and eats parasites and other materials from the surface of the other (the client). Cleaning symbiosis is well-known amon ...
with larger, often predatory, fish, grooming them and benefiting by consuming what they remove. "Client" fish congregate at wrasse "
cleaning stations" and wait for the cleaner fish to remove
gnathiid parasites, the cleaners even swimming into their open mouths and gill cavities to do so. A single wrasse works for around four hours a day, and in that time, it can inspect more than 2,000 clients.
["The Fish That Makes Other Fish Smarter"]
by Ed Yong, ''The Atlantic'', March 7, 2018
Cleaner wrasses are best known for feeding on dead tissue, scales, and
ectoparasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s, although they are also known to '
cheat
Cheating generally describes various actions designed to subvert rules in order to obtain unfair advantages. This includes acts of bribery, cronyism and nepotism in any situation where individuals are given preference using inappropriate cr ...
', consuming healthy tissue and mucus, which is energetically costly for the client fish to produce. The
bluestreak cleaner wrasse
The bluestreak cleaner wrasse, ''Labroides dimidiatus'', is one of several species of cleaner wrasses found on coral reefs from Eastern Africa and the Red Sea to French Polynesia. Like other cleaner wrasses, it eats parasites and dead tissue o ...
, ''Labroides dimidiatus'', is one of the most common cleaners found on tropical reefs. Few cleaner wrasses have been observed being eaten by predators, possibly because parasite removal is more important for predator survival than the short-term gain of eating the cleaner.
When cleaner wrasses were experimentally removed from a reef in Australia, the total number of fish species halved, and their numbers fell by three-quarters. Also, some evidence, from another Australian study, shows that cleaned fish are smarter than those not served by the wrasse.
[
According to a 2019 study, cleaner wrasses have become the first fish ever observed to pass the mirror test. However, the test's inventor, American psychologist Gordon G. Gallup, has said that the fish were most likely trying to scrape off a perceived parasite on another fish and that they did not demonstrate self-recognition. The authors of the study retorted that because the fish checked themselves in the mirror before and after the scraping, this meant that the fish had self-awareness and recognized that their reflections belonged to their own bodies.]
Tool use
Studies show that some wrasse species are capable of tool use, using rocks to smash open sea urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...
s.
Significance to humans
In the Western Atlantic coastal region of North America, the most common food species for indigenous humans was the tautog, a species of wrasse. Wrasses today are commonly found in both public and home aquaria. Some species are small enough to be considered reef safe
Reef safe is a distinction used in the saltwater aquarium hobby to indicate that a fish or invertebrate is safe to add to a reef aquarium. There is no fish that is completely reef safe. Every fish that is commonly listed as reef safe are species th ...
. They may also be employed as cleaner fish to combat sea-lice infestations in salmon farms. Commercial fish farming of cleaner wrasse for sea-lice pest control in commercial salmon farming has developed in Scotlan
as lice busters
with apparent commercial benefit and viability.
Parasites
As all fish, labrids are the hosts of a number of parasites. A list of 338 parasite taxa from 127 labrid fish species was provided by Muñoz and Diaz in 2015.[Muñoz G., Diaz P.E. 2015: Checklist of parasites of labrid fishes (Pisces: Labridae). Viña del Mar, Chile]
PDF
An example is the nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
'' Huffmanela ossicola''.
Gallery
Image:Giant Napoleon Wrasse in Shark Point Dive Site, Apo Reef, Philippines.jpg, Giant Napoleon wrasse '' Cheilinus undulatus'' in Apo Reef, Philippines
Image:Humphead wrasse melb aquarium.jpg, Humphead wrasse, '' Cheilinus undulatus'', Melbourne Aquarium
Image:Coris gaimard real.jpg, Yellowtail wrasse, ''Coris gaimard
''Coris gaimard'', the yellowtail wrasse or African coris, among other vernacular names, is a species of wrasse native to the tropical waters of the central Indian Ocean and the western Pacific Ocean, from Christmas Islands and Cocos Keeling Isl ...
'', Hawaii
Image:Coris_gaimard_and_Labroides_phthirophagus.JPG, A yellowtail coris wrasse, ''Coris gaimard'', is being cleaned by ''Labroides phthirophagus
The Hawaiian cleaner wrasse or golden cleaner wrasse (''Labroides phthirophagus''), is a species of wrasse (genus ''Labroides'') found in the waters surrounding the Hawaiian Islands. The fish is endemism, endemic to Hawaii. These cleaner fish inh ...
'' in Hawaii.
Image:Bird Wrasse.jpg, Bird wrasse, ''Gomphosus varius
The bird wrasse, ''Gomphosus varius'', is a species of the wrasse family.
Description
The bird wrasse is a medium-sized fish which can reach a standard length of . It has an elongated body, laterally compressed, with a truncated tail and a long ...
'', Kona (Hawaii)
Image:Gomphosus.jpg, ''Gomphosus varius
The bird wrasse, ''Gomphosus varius'', is a species of the wrasse family.
Description
The bird wrasse is a medium-sized fish which can reach a standard length of . It has an elongated body, laterally compressed, with a truncated tail and a long ...
''
Image:Birdmouth wrasse.jpg, ''Gomphosus caeruleus
''Gomphosus caeruleus'', the green birdmouth wrasse, is a species of wrasse belonging to the family Labridae. It can be found in the aquarium trade.
Distribution and habitat
This tropical species of wrasse is native to the Indian Ocean, from ...
'' swimming with a yellow goatfish
The yellow goatfish (''Mulloidichthys martinicus''), also known as yellowsaddle, is a species of goatfish native to the Atlantic Ocean around the coasts of Africa and the Americas. This species can reach a total length of , but most reach length ...
Image:Bluhead Wrasse.jpg, Bluehead wrasse, Belize Barrier Reef
Image:Clown wrasse coris aygula.JPG, Clown wrasse, '' Coris aygula'', Red Sea
Image:Anampses cuvieri.jpg, Pearl wrasse, ''Anampses cuvieri
''Anampses'' is a genus of wrasses native to the Indian and Pacific Oceans.
Species
The currently recognized species in this genus are:
* '' Anampses caeruleopunctatus'' Rüppell, 1829 (blue-spotted wrasse)
* '' Anampses chrysocephalus'' J. ...
'', Hawaii
Image:Ladim u0.gif, Bluestreak wrasse, '' Labroides dimidiatus''
Image:Six-line wrasse.jpg, Six-line wrasse '', Pseudocheilinus hexataenia
The six-line wrasse (''Pseudocheilinus hexataenia'') is a species of marine ray-finned fish from the family Labridae which has a wide Indo-Pacific distribution. This species is associated with coral reefs and can be found in the aquarium trade.
...
''
File:A history of Scandinavian fishes (9661319663).jpg, Cuckoo wrasse by Wilhelm von Wright
Classification
Subgroups and tribes
Genera
Timeline
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from: -55.8 till: -33.9 color:eocene text: Eocene
from: -33.9 till: -23.03 color:oligocene text:Oligocene
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from: -23.03 till: -2.588 color:neogene text:Neogene
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color:eocene bar:NAM3 from: -48.6 till: 0 text: Symphodus
''Symphodus'' is a genus of wrasses native to the eastern Atlantic Ocean and the Mediterranean Sea.
Species
The currently recognized species in this genus are:
* '' Symphodus bailloni'' (Valenciennes, 1839) (Baillon's wrasse)
* '' Symphodus caer ...
color:oligocene bar:NAM4 from: -33.9 till: 0 text: Cheilinus
color:miocene bar:NAM5 from: -15.97 till: 0 text: Bodianus
color:pliocene bar:NAM6 from: -5.332 till: 0 text: Oxyjulis
color:pleistocene bar:NAM7 from: -2.588 till: 0 text: Pimelometopon
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from: -55.8 till: -33.9 color:eocene text: Eocene
from: -33.9 till: -23.03 color:oligocene text:Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
from: -23.03 till: -5.332 color:miocene text: Miocene
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The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
from: -23.03 till: -2.588 color:neogene text:Neogene
The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...
from: -2.588 till: 0 color:quaternary text: Q.
References
*
External links
FishBase info for Labridae
Male and Female Images or Rock Wrasse Fish
* Smith, J.L.B. 1957
List of the fishes of the Family Labridae in the Western Indian Ocean
Ichthyological Bulletin; No. 7. Department of Ichthyology, Rhodes University, Grahamstown, South Africa.
*
{{Authority control
Labriformes
Taxa named by Georges Cuvier
Articles which contain graphical timelines