''Champsocephalus esox'', the pike icefish or northern icefish, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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

, the

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

es.

Taxonomy

''Champsocephalus esox'' was first formally described in 1861 as ''Chaenichthys esox'' by the German-born British

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

Albert Günther Albert Karl Ludwig Gotthilf Günther , also Albert Charles Lewis Gotthilf Günther (3October 18301February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile tax ...

with the type locality given as Port Famine in Chile. In 1862 the American ichthyologist

Theodore Nicholas Gill Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist, and librarian. Career Born and educated in New York City under private tutors, Gill early showed interest in natural histor ...

placed it in the 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 "unisp ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Champsocephalus''. The ''specific name'' ''esox'' means "pike", Günther did not explain why but it may be because of the resemblance to the

Northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (pikes). They are commonly found in brackish water, moderately salty and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). T ...

(''Esox lucius'').

Description

''Champsocephalus esox'' has a whitish body, dark brown

caudal fins Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only by ...

, and dark brown bars (sometimes forming irregular dark blotches connected with yellowish regions) with no scales except on its

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

Distribution and habitat

''Champsocephalus esox'' is found at depths of in the oceans off

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

, the

Falklands The Falkland Islands (; ), commonly referred to as The Falklands, is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and from Cape Du ...

and rarely

South Georgia South Georgia is an island in the Atlantic Ocean, South Atlantic Ocean that is part of the British Overseas Territories, British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. ...

. It is the only species of crocodile icefish found north of the Antarctic Polar Frontal Zone, with only 3 specimens reported south of the

CCAMLR The Convention on the Conservation of Antarctic Marine Living Resources, also known as the Commission for the Conservation of Antarctic Marine Living Resources, and CCAMLR, is part of the Antarctic Treaty System. The convention was opened for s ...

area

Biology

''Champsocephalus esox'' is a

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer o ...

species that reaches in length and mainly feeds on fishes and

krill Krill ''(Euphausiids)'' (: krill) are small and exclusively marine crustaceans of the order (biology), order Euphausiacea, found in all of the world's oceans. The name "krill" comes from the Norwegian language, Norwegian word ', meaning "small ...

. A South Georgian study in 1981 collected a specimen with stomach contents of 90% krill ('' Euphasia superba'') and 10% fish.

Fisheries

''Champsocephalus esox'' is of minor importance to

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often p ...

, with catches in 2008 amounting to a total of 90 tonnes. The fish are trawled from January to March, but none are caught in the winter.

Conservation

''Champsocephalus esox'' stocks have declined by 80% along the coast of Chile since the 1980s while the state of the stock in Argentina is unclear as there has been little attempt to survey this population. The

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

conservatively estimate the population to have suffered an overall decline of 30% over the three most recent generation lengths, i.e. 12-18 years. This species is threatened by climate change leading to warmer water temperatures, mortality as a result of bycatch by artisanal fishers and by invasive

salmonids Salmonidae (, ) is a family of ray-finned fish, the only extant member of the suborder Salmonoidei, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmon (both Atlantic a ...

. The IUCN is listed as Vulnerable and state that additional survey work is required to monitor and understand population status wherever it occurs and that research on its life history and its response to warming waters should be undertaken.

References

{{Taxonbar, from=Q4472286

esox ''Esox'' is a genus of freshwater fish commonly known as pike or pickerel. It is the type genus of the family (biology), family Esocidae. The type species of the genus is ''Esox lucius'', the northern pike. ''Esox'' have a fossil record exten ...

Fish of the Western Atlantic Western South American coastal fauna Fauna of the Falkland Islands pike icefish Taxa named by Albert Günther