The rock cook (''Centrolabrus exoletus''), or small-mouthed wrasse, is a species of marine ray-finned fish from the wrasse family Labridae which is found in the eastern Atlantic Ocean off the coasts of Europe.

Description

The rock cook is a small wrasse in which the adults range in length from . Its mouth is relatively small and has thick, fleshy lips. This species is normally reddish-brown above fading to yellowish-silver on the flanks and to pale silvery-white on the belly. The males have iridescent blue streaks on their dorsal, anal and caudal fins as well as on their heads. The caudal fin has a dark vertical bar. There is a single row of small teeth in the jaws.

Distribution

The rock cook is found in the eastern Atlantic where it is endemic to European waters from Norway to Portugal. It has been claimed off eastern Greenland but these records are regarded as doubtful. It is absent from the Baltic Sea and has been observed once in the Mediterranean Sea off

Málaga Málaga (, ) is a municipality of Spain, capital of the Province of Málaga, in the autonomous community of Andalusia. With a population of 578,460 in 2020, it is the second-most populous city in Andalusia after Seville and the sixth most pop ...

in 1981.Atlas of Exotic Fishes in the Mediterranean Sea (Centrolabrus exoletus). 2nd Edition. 2021. 366p. CIESM Publishers, Paris, Monaco.https://ciesm.org/atlas/fishes_2nd_edition/Centrolabrus_exoletus.pdf In the waters off Britain and Ireland it is absent from the eastern English Channel and the eastern coast of England.

Habitat and biology

The rock cook is found mainly among seaweeds and seagrass beds on or near rocks and boulders normally at depths of less than , although it has been claimed at depth of off the United Kingdom. The female creates a nest from fine seaweeds in which she lays her eggs during the summer months. Its diet consists of small

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

invertebrates, especially crustaceans. Males grow faster than the females, by the age of 5 years old the males attain an average length of while the females average length is . The rock cook also acts as a cleaner fish and a study off the coast of the Algarve, Portugal found that it was the most important species of cleaner fish present in that area. It is a facultative cleaner fish which rather than maintain a territory where its client fish seek it out small groups of rock cooks actively search for client fish, primarily the

brown wrasse The brown wrasse (''Labrus merula'') is a species of wrasse native to the Eastern Atlantic from Portugal to Morocco, including the Azores, as well as in the Mediterranean Sea. This species can reach in standard length, though most do not ...

in this study, and clean and consume crustacean ectoparasites, all from the family Gnathiidae, off the client fish.

Human uses

The rock cook is used in the

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...

of the

Atlantic salmon The Atlantic salmon (''Salmo salar'') is a species of ray-finned fish in the family Salmonidae. It is the third largest of the Salmonidae, behind Siberian taimen and Pacific Chinook salmon, growing up to a meter in length. Atlantic salmon are ...

as a cleaner fish.

Taxonomy

''Centrolabrus exoletus'' is the type species of the genus ''

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 ...

''. It was originally formally described by Carolus Linnaeus in 1758 in the 10th Edition of the ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

''.

References

{{Taxonbar, From=Q533844 Fish described in 1758 Taxa named by Carl Linnaeus Rock cook