''Medialuna ancietae'' 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 ...

sea chub The sea chubs, also known as rudderfish and pilot fish and in Hawaiian as ''enenue'' or ''nenue'', are a family, Kyphosidae, of fishes in the order Perciformes native to the Atlantic, Indian and Pacific Oceans usually close to shore in marine w ...

native to the Pacific coast of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

where it inhabits the

giant kelp ''Macrocystis pyrifera'', commonly known as giant kelp or bladder kelp, is a species of kelp (large brown algae), and one of four species in the genus ''Macrocystis''. Despite its appearance, it is not a plant; it is a heterokont. Giant kelp is ...

forests. It is known locally as ''acha'', ''mero del sur'' or ''chino''.

Description

Sea chubs are medium-sized fish with small heads, blunt snouts and laterally compressed bodies. The small mouth contains a row of short teeth with hockey-stick shaped tips. The dorsal fin is continuous and has 11 to 14 spines, which can be folded down into a groove, and 11 to 13 soft rays. The anal fin has three spines and 11 to 13 soft rays. The body is clad in small scales which are thick and feel rough. The colour is mainly drab, the belly being paler than the upper parts. ''M. ancietae'' can grow to a maximum weight of .

Distribution and habitat

''M. ancietae'' is native to the subtropical southeastern Pacific Ocean where it is found on the coasts of Peru and Chile. Its habitat is the forests of giant kelp that line the rocky shore subtidally. The dominant species of kelp along this coast are ''

Lessonia trabeculata ''Lessonia trabeculata'' is a species of kelp, a brown alga in the genus '' Lessonia''. It grows subtidally off the coasts of Peru and northern and central Chile, with the closely related ''Lessonia nigrescens'' tending to form a separate zone in ...

'' subtidally and ''

Lessonia nigrescens ''Lessonia nigrescens'', the grey weed or giant grey weed, is a South American kelp species in the genus '' Lessonia''. There is at least two populations of the seaweed, marked by the difference in phenolic content. There is a subtidal populatio ...

'' intertidally; these can grow to a length of and provide a dense tangled environment.

Uses

''Medialuna ancietae'' is esteemed as a sport fish and is the subject of both recreational and artisanal spear-fishing. Historically, along with ''

Graus nigra ''Graus nigra'' is a species of sea chub endemic to the Pacific coast of South America, ranging from Valdivia in Chile to southern Peru. This species grows to a total length of . It is popular as a game fish. This species is the only known memb ...

'' and the Chilean sheepshead (''

Semicossyphus darwini ''Semicossyphus darwini'' is a species of ray-finned fish native to the tropical eastern Pacific Ocean. Common names include the Chilean sheepshead wrasse, the goldspot sheepshead or the Galapagos sheepshead wrasse. Description This is a large w ...

''), ''M. ancietae'' constituted more than 98% of the fish caught by spear-fishing. However, unregulated fishing has reduced the numbers of these fish to such an extent that by 2015, ''M. ancietae'' was rarely seen; the community structure of the kelp forest has been affected by this reduction in the populations of carnivorous fishes.

References

{{Taxonbar, from=Q1820888 Scorpidinae Fish of Chile Fish of Peru Western South American coastal fauna Fish described in 1987