''Gobionotothen gibberifrons'', the humped rockcod or the humphead notothen, is a species 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 hor ...

belonging to the

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

Nototheniidae : ''In some scientific literature, the term "cod icefish" is used to identify members of this family. This should not be confused with the term "icefish," which refers to the "white-blooded" fishes of the family Channichthyidae. See Icefish (disam ...

, the notothens or cod icefishes. It is native to the islands of the

Scotia Arc The Scotia Arc is the island arc system forming the north, east and south border of the Scotia Sea. The northern border, the North Scotia Ridge, comprises (from west to east) Isla de los Estados at the tip of Tierra del Fuego, the Burdwood, Davis, ...

(the

South Shetland The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 195 ...

South Orkney The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic PeninsulaSouth Sandwich and

South Georgia South Georgia ( es, Isla San Pedro) is an island in the South Atlantic Ocean that is part of the British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. Stretching in the east� ...

islands), the northern part of the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

, and

Heard Island The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size ...

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 ...

. This species inhabits depths of 6-429 m (20-1,407 ft), but is most abundant at depths of 100-400 m (328-1,312 ft), at least around

Elephant Island Elephant Island is an ice-covered, mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands, in the Southern Ocean. The island is situated north-northeast of the tip of the Antarctic Peninsula, west-so ...

Taxonomy and etymology

''Gobionotothen gibberifrons'' was first formally described in 1905 as ''Notothenia gibberifrons'' 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, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

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 Hi ...

with the type locality given as the seven locations around

in the

. The specific name ''gibberifrons'' is a compound of ''gibber'' which means "humpbacked" and ''frons'' meaning "forehead", an allusion to the convex forehead.

Description

This species is distinguished by its steep snout profile, narrow interorbital region (or the interorbital space) and humped forehead (the head is depressed behind the eyes). 1-2 series of small, conical teeth are present on each jaw, and the

gill rakers 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 ...

are short. The general body color is yellowish with irregular dark spots and blotches present on the upper part of the head and body. Juveniles have irregular cross-bars on the body (broken up into three or four series of alternating spots) that are rarely present in adults. The

fins A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...

are greenish (with the only exception being the

anal 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 se ...

which is pale with 2-3 horizontal bands). The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

, caudal and

pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectorali ...

fins have a series of brown spots present that form transverse bands. The maximum recorded length of this species is 55 cm (21.7 inches), but a length of 40 cm (15.7 inches) is more common.

Ecology

This species 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 ...

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

that feeds on

polychaetes Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are mad ...

echiurans The Echiura, or spoon worms, are a small group of marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids typically have their bodies divided into segments, but echiurans have secondarily los ...

, sipunculids,

priapulids Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' ' Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertili ...

bivalves Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

and

crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

. If

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 Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...

is abundant, this species will feed heavily on it. Fish eggs are also taken when available. This species reaches sexual maturity at 36 cm (14.2 inches) TL for both sexes. Males first

spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: ...

at 36 cm TL and females first spawn at 38.6 cm (15.2 inches) TL. Mature females may spawn for the first time at 6-8 years of age, and up to 143,620 eggs of up to 2.5 mm diameter may be laid. Spawning occurs from late winter to early spring (the exact months are different from place to place: i.e. August-September around Elephant Island and July-August at South Georgia). Hatching takes place in spring and early summer, and length at hatching is around 7 mm SL. The larvae appear in the water column in September around South Georgia and in November around Elephant Island. The larvae only end their

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

phase at the end of summer and change to a benthopelagic lifestyle from that time on. Predators include the

marbled rockcod The marbled rockcod (''Notothenia rossii'') is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the Southern Ocean, where it can be found at depths from . This is a comme ...

''(Notothenia rossii)'', South Georgia icefish ''(Pseudochaenichthys georgianus)'', blackfin icefish ''(Chaenocephalus aceratus)'',

imperial shag The imperial shag or imperial cormorant (''Leucocarbo atriceps'') is a black and white cormorant native to southern South America, primarily in rocky coastal regions, but locally also at large inland lakes. Some taxonomic authorities, including ...

''(Phalacrocorax atriceps)'' and the

Antarctic fur seal The Antarctic fur seal (''Arctocephalus gazella''), is one of eight seals in the genus '' Arctocephalus'', and one of nine fur seals in the subfamily Arctocephalinae. Despite what its name suggests, the Antarctic fur seal is mostly distributed i ...

''(Arctocephalus gazella)''.

Commercial importance

This species 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 ...

at present, but it once was heavily fished (total catches amounted to 21,800 tonnes (24,030 tons) in the year 1978 alone).

References

{{Taxonbar, from=Q1926606 gibberifrons Fauna of South Georgia and the South Sandwich Islands Fish of the Southern Ocean Taxa named by Einar Lönnberg