''Channichthys'' is a genus of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

belonging to the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Channichthyidae The crocodile icefish or white-blooded fish comprise a family (Channichthyidae) of notothenioid fish found in the Southern Ocean around Antarctica. They are the only known vertebrates to lack hemoglobin in their blood as adults. Icefish populatio ...

, the

crocodile icefish The crocodile icefish or white-blooded fish comprise a family (Channichthyidae) of notothenioid fish found in the Southern Ocean around Antarctica. They are the only known vertebrates to lack hemoglobin in their blood as adults. Icefish populatio ...

es. They are native to the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

Taxonomy

''Channichthys'' was first formally described as a genus in 1844 by the Scottish

naval surgeon A naval surgeon, or less commonly ship's doctor, is the person responsible for the health of the ship's company aboard a warship. The term appears often in reference to Royal Navy's medical personnel during the Age of Sail. Ancient uses Speciali ...

, naturalist and Arctic explorer John Richardson when he described the unicorn icefish (''Channichthys rhinoceratus'') which he placed in a new

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

genus. Subsequently up to nine species have been classified within ''Channichthys'' which is what FishBase does while ''

Catalog of Fishes Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously u ...

'' recognises 5 species while other authorities are of the view that the genus is monotypic and that ''C. rhinoceratus'' is the only species. The genus name is a compound of ''channos'' meaning "gape" and ''ichthys'' which means "fish", alluding to the wide gape of these fishes.

Species

The species of this genus are quite similar to each other, and reliable ways of distinguishing them include the shape of their

dorsal fins A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

count and relative eye diameter to snout length. * '' Channichthys aelitae'' – Aelita icefish * '' Channichthys bospori'' – big-eyed icefish * '' Channichthys irinae'' – pygmy icefish * '' Channichthys mithridatis'' – green icefish * '' Channichthys panticapaei'' – charcoal icefish * '' Channichthys rhinoceratus'' – unicorn icefish * '' Channichthys richardsoni'' – robust icefish * '' Channichthys rugosus'' – red icefish * '' Channichthys velifer'' – sail icefish

Characteristics

''Channichthys'' icefishes may have a backwards pointing spine on the snout and small tubercles on the upper surface of the head. The operculum has 5-7 robust spines with blunt spines on the other opercular bones. They have 2 lateral lines which have bony plates, although they may have other plates on their flanks. In the pelvic fin the third ray is longer than the others, The first

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

is tall and in large specimens the fin rays have small tubercles on them. The first and second dorsal fins are clearly separated. They have a rounded

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

. They have a maximum standard length which varies from in ''C. rugosus'' to in ''C. mithridatis''.

Distribution, habitat and biology

''Channichthys'' icefishes are restricted to the

Kerguelen The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large ...

- Heard region of the Indian sector of the Southern Ocean. They are demersal fishes. They are mainly

piscivorous A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...

but will also eat algae. They spawn in the summer and migrate into shallow water to do so.

Fisheries

''Channichthys'' icefishes, particularly ''C. rhinoceratus'', are caught as bycatch in botton trawls for the mackerel icefish (''Champsocephalus gunnari'').

References

{{Taxonbar, from=Q2580922 Channichthyidae Fish of the Southern Ocean