Jonah's icefish (''Neopagetopsis ionah'') 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 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 ...

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 ...

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. It is the only member of the

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 "unispec ...

genus ''Neopagetopsis''. It is 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 ...

at depths of from . It has a circum-

Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...

distribution on the

continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

and

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

, with the northernmost records from 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 ...

and the

South Orkney Islands The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsuladescribed in 1947 by the Swedish ichthyologist with the type locality given as near the

Balleny Islands The Balleny Islands () are a series of uninhabited islands in the Southern Ocean extending from 66°15' to 67°35'S and 162°30' to 165°00'E. The group extends for about in a northwest-southeast direction. The islands are heavily glaciated an ...

Ross Dependency The Ross Dependency is a region of Antarctica defined by a sector originating at the South Pole, passing along longitudes 160° east to 150° west, and terminating at latitude 60° south. It is claimed by New Zealand, a claim accepted only b ...

in Antarctica. It is the only species in the genus ''Neopagetopsis''. The genus name is a compound of ''neo'' which means "new"; and ''

Pagetopsis ''Pagetopsis'' is a genus of marine ray-finned fish belonging to the family Channichthyidae, the crocodile icefishes. The species in this genus are found in the Southern Ocean. Taxonomy ''Pagetopsis'' was described as a genus in 1913 by the Engl ...

'', the name of a related genus to which this taxon bears a resemblance, but differs by having long

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s and three

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 epithelial ...

s. The specific name refers to the

Biblical prophet In religion, a prophet or prophetess is an individual who is regarded as being in contact with a divine being and is said to speak on behalf of that being, serving as an intermediary with humanity by delivering messages or teachings from the s ...

Jonah Jonah or Jonas, ''Yōnā'', "dove"; gr, Ἰωνᾶς ''Iōnâs''; ar, يونس ' or '; Latin: ''Ionas'' son of Amittai, is a prophet in the Hebrew Bible and the Quran, from Gath-hepher of the northern kingdom of Israel in about the 8th cent ...

and is an allusion to the type being collected from the stomach of a whale.

Description

Jonah's icefish has a forward curving spine on the snout. There are 3-4 radiating ridges on the operculum, each ending at its rear with a spine; none of the other opercular bones have spines. The three lateral lines do not have any bony plates. The first and second

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 conv ...

s are continuous. The dorsal fins hold 14-15 spines and 32-35 soft rays while 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 ...

contains 29-32 soft rays. The well-developed first dorsal fins and fan-shaped

s are blackish while the other fins may be dusky or blackish in color. The overall color is a dark blackish-green or black on the body, although the belly is whitish; those of juveniles may have irregular dark markings present. This species attain a maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of .

Distribution and habitat

Jonah's icefish is found in the Southern Ocean where it is circum-Antarctic on the continental shelf and slope, with the northernmost reports coming from the South Shetland and South Orkney Islands. It is a benthopelagic species which occurs at depths between . In January 2014 the first nesting Jonah’s icefish records were made, and in February 2021 a larger colony estimated to be composed of approximately 60 million Jonah's icefish was found, both colonies were discovered inhabiting the Filchner Trough in the southern

Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...

, off the coast of Antarctica between . It is estimated that colony discovered in 2021 covers around , with an average of one nest every and a total

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

of of fish.

Biology

Jonah's icefish mainly feeds on

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

, such as '' Dacodraco hunteri'', ''

Chaenodraco wilsoni ''Chaenodraco wilsoni'', the spiny icefish, is a species of marine ray-finned fish belonging to the Family (biology), family Channichthyidae, the crocodile icefishes. It is native to the Southern Ocean. This species is the only known member of its ...

'', '' Pleuragramma antarcticum'' and ''

Chionodraco ''Chionodraco'' is a genus of marine ray-finned fish belonging to the family Channichthyidae, the crocodile icefishes. They are found in the Southern Ocean. Taxonomy ''Chionodraco'' was first described as a genus in 1905 by the Swedish zoologist ...

'' sp., as well as

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 ...

, as adults. Young specimens, however, feed mainly on krill, especially ''

Euphausia superba Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 ind ...

'', and they are frequently caught along with their prey at total length. In the South Shetland Islands, both adults and juveniles show a marked preference for krill (only 3 out of 19 sampled specimens had consumed any kind of fish). This species has a more complete

hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...

gene than other species of crocodile icefish; however, it is still nonfunctional.

Fisheries

Jonah's icefish is of no interest 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 ...

Description

Distribution and habitat

Biology

Fisheries

References

Further reading