''Notothenia microlepidota'', the black cod or small-scaled cod, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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 ...

Nototheniidae, the notothens or cod icefishes. It is native to the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

waters around

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

and

Macquarie Island Macquarie Island is a subantarctic island in the south-western Pacific Ocean, about halfway between New Zealand and Antarctica. It has been governed as a part of Tasmania, Australia, since 1880. It became a Protected areas of Tasmania, Tasmania ...

. This species can reach a

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

of . It is a commercially important species.

Taxonomy

''Notothenia microlepidota'' was first formally described in 1875 by the English-born New Zealand scientist Frederick Wollaston Hutton with the type locality given as

Dunedin Dunedin ( ; ) is the second-most populous city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from ("fort of Edin"), the Scottish Gaelic name for Edinburgh, the capital of S ...

and Dunedin and

Moeraki Moeraki is a small fishing village on the east coast of the South Island of New Zealand. It was once the location of a whaling station. In the 1870s, local interests believed it could become the main port for the north Otago area and a railwa ...

in New Zealand. The specific name ''microlepidota'' means "small scaled" which is thought to be a reference to its small, numerous scales when compared to '' N. angustata'' which Wollaston described in the same

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...

Description

''Notothenia microlepidota'' juveniles have a silvery appearance and their

caudal fin 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 ...

is clearly forked. The adults have a less obviously forked caudal fin. The colour of the body is silver, yellow and reddish-brown. The body is covered in very small scales and there are two lateral lines which have a considerable overlap. The shortbased first

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

has 6-7 spines, the second dorsal fin has 27-28 soft rays while the

anal fin 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 o ...

has 23-24 soft rays. This species attains a maximum

of .

Distribution and habitat

''Notothenia microlepidota'' is restricted to New Zealand and

in the southwestern Pacific Ocean. They have been found in depths of a few metres off Campbell Island and have been trawled at offshore.

Biology

In the Campbell Plateau,

salp A salp (: salps, also known colloquially as “sea grape”) or salpa (: salpae or salpas) is a barrel-shaped, Plankton, planktonic tunicate in the family Salpidae. The salp moves by contracting its gelatinous body in order to pump water thro ...

s are the most important prey, followed by

amphipods Amphipoda () is an order (biology), order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods () range in size from and are mostly detritivores or scavengers. There are more than 10,700 amphip ...

(particularly '' Parathemisto gaudichaudii'') and percophidids.

Crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s such as the portunid crab '' Nectocarcinus bennetti'' are also important prey. These prey items imply benthic feeding habits, typical for notothenids. Being a

subantarctic The sub-Antarctic zone is a physiographic region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46th parallel south, 46° and 60th parallel south, 60° south of t ...

species, the black cod has special adaptations such as

antifreeze protein Antifreeze proteins (AFPs) or ice structuring proteins refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small ...

s in its

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

, as well as

adipose Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...

tissues to offset its lack of a

swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ (anatomy), organ in bony fish that functions to modulate buoyancy, and thus allowing the fish to stay at desired water depth without having to maintain lift ...

, giving it neutral buoyancy. The

sablefish The sablefish (''Anoplopoma fimbria'') is one of two members of the fish family Anoplopomatidae and the only species in the genus ''Anoplopoma''. In English, common names for it include sable (US), butterfish (US), black cod (US, UK, Canada), ...

, '' Anoplopoma fimbria'', is occasionally called black cod, as well, but it is not a true cod. In New Zealand, the Maori cod is also known as "black cod". They are a common prey item of seals.

References

* Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd, Auckland, New Zealand 1982) {{Taxonbar, from=Q2517939 microlepidota Fish of the Pacific Ocean Marine fish of New Zealand Fish described in 1875 Taxa named by Frederick Hutton (scientist)