The mackerel icefish (''Champsocephalus gunnari'') is a

benthopelagic 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 of ...

species of fish found in 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 ...

and the southernmost waters of the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

. They are mainly to be found near Heard and

McDonald Islands The McDonald Islands () are an uninhabited archipelago in the southern Indian Ocean in the vicinity of Heard Island (). Together with Heard Island, they make up the Australian external Territory of Heard Island and McDonald Islands. The McDona ...

, Îles Kerguelen and islands in the

south Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

such as South Georgia and

Bouvet Island Bouvet Island ( ; or ''Bouvetøyen'') is an island claimed by Norway, and declared an uninhabited protected nature reserve. It is a subantarctic volcanic island, situated in the South Atlantic Ocean at the southern end of the Mid-Atlantic R ...

. The species also inhabits the northern waters of the Antarctic Peninsula. They live at depths of , but are commonly found at depths of .

Taxonomy

The mackerel icefish was first formally described in 1905 by the Swedish

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and d ...

Einar Lönnberg Axel Johann Einar Lönnberg (24 December 1865 – 21 November 1942) was a Swedish zoologist and conservationist. Lönnberg was born in Stockholm. He was head of the Vertebrate Department of the '' Naturhistoriska Riksmuseet'' (Swedish Natural H ...

with the type locality given as South Georgia. The specific name honours the archaeologist,

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althoug ...

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Johan Gunnar Andersson Johan Gunnar Andersson (3 July 1874 – 29 October 1960)"Andersson, Johan Gunnar" in ''The New Encyclopædia Britannica''. Chicago: Encyclopædia Britannica Inc., 15th edn., 1992, Vol. 1, p. 385. was a Swedish archaeologist, paleontologist and ge ...

who was leader of the

Swedish Antarctic Expedition The Swedish Antarctic Expedition of 1901–1903 was a scientific expedition led by Otto Nordenskjöld and Carl Anton Larsen. It was the first Swedish endeavour to Antarctica in the Heroic Age of Antarctic Exploration. Background Otto Nordensk ...

, on which the type was collected. Champsocephalus gunnari

Description

The mackerel icefish has a long, spindle-shaped body with whitish

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

and a bluish-silver color. It has an elongated snout and a large mouth with small teeth. The

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 ...

are black in adults and the second caudal fins and anal fins of adult males have distinctive white margins. The mackerel icefish can grow to in standard length, but is more commonly about TL. It has a maximum published weight of . This species is markedly smaller in the Kerguelen Islands, where they only reach 45 cm (17 inches) TL. (pp. 385-386) In: O. Gon and P.C. Heemstra(eds). 1990. Fishes of the Southern Ocean. J.L.B.Smith Institute of Ichthyology, Grahamstown.

Ecology

This species has a maximum lifespan of 15 years and eats

krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...

(making up more than 95% of the diet in more southerly areas) and

mysids Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this p ...

. Myctophids are also taken, at least in South Georgia and the Kerguelen Islands. They are in turn preyed on by

seabirds Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same envi ...

seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...

and other notothens. This species practices daily vertical migration and is a schooling species. This species, which becomes reproductively mature at 3–4 years old, is a synchronous spawner and spawns in the Southern Hemisphere autumn and winter. Sexually mature males have a significantly higher dorsal fin than females. This species moves inshore to spawn. Females produce 10 000 to 20 000 large eggs that remain on the seabed for about 3 months before hatching. Hatching takes place from August to October in South Georgia and in October around the Kerguelen Islands. The larvae have a long pelagic phase.

Relationship with humans

This species has slightly oily, yet mild-tasting flesh of excellent quality, and is of 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 2007 amounting to a total of 4364 tonnes (4810 tons). It is targeted mainly using

bottom trawling Bottom trawling is trawling (towing a trawl, which is a fishing net) along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing ...

. Due to historic overfishing (more than 168 thousand tonnes of this fish were landed in the year 1978 alone), the

United Nations Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

(FAO) considers the species "depleted", however, the

Marine Stewardship Council The Marine Stewardship Council (MSC) is a non-profit organization which aims to set standards for sustainable fishing. Fisheries that wish to demonstrate they are well-managed and sustainable compared to the MSC's standards are assessed by a te ...

has certified the Heard Island Mackerel Icefish fishery as sustainable and well managed. This fishery has been certified since 2006.

References

{{Taxonbar, from=Q2346450 mackerel icefish Fish of the Southern Ocean Fish of the Atlantic Ocean Fauna of Heard Island and McDonald Islands Fauna of the Kerguelen Islands mackerel icefish Taxa named by Einar Lönnberg Fauna of South Georgia and the South Sandwich Islands Fish of Antarctica