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

commercially Commerce is the large-scale organized system of activities, functions, procedures and institutions directly and indirectly related to the exchange (buying and selling) of goods and services among two or more parties within local, regional, nation ...

important species.

Taxonomy

The marbled rockcod was first formally described in 1844 by the Scottish naval surgeon, naturalist and

Arctic explorer Arctic exploration is the physical exploration of the Arctic region of the Earth. It refers to the historical period during which mankind has explored the region north of the Arctic Circle. Historical records suggest that humankind have explored ...

John Richardson with no type locality given, although it is thought likely to be Kerguelen Island. Richardson gave it the specific name ''rossii'' which honours James Clark Ross, the leader of the

Ross expedition The Ross expedition was a voyage of scientific exploration of the Antarctic in 1839 to 1843, led by James Clark Ross, with two unusually strong warships, HMS ''Erebus'' and HMS ''Terror''. It explored what is now called the Ross Sea and discov ...

, a scientific expedition by the vessels HMS ''Erebus'' and HMS ''Terror'' to survey and explore the coasts of Antarctica.

Description

The marbled rockcod can reach a length of , though a more common length is around . The greatest recorded weight for this species is . The dorsal fin is divided in two parts, with four to seven spines in the front portion and 32 to 36 soft rays in the long, back portion. 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 ...

has 26 to 30 soft rays. The colour and pattern varies but it is typically dark brown with dark marbling on the upper body, paler on the lower body. The first dorsal fin has a dark spot in the membrane between each spine. The juveniles are yellowish or golden in colour during their benthic phase while the pelagic juveniles are silvery.

Distribution

The marbled rockcod's range includes the northern end 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 ...

, the Scotia Arc, Prince Edward Islands,

Crozet Islands The Crozet Islands (french: Îles Crozet; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarcti ...

Kerguelen Islands The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large ...

, Heard Island and Macquarie Island, as well as the Ob Bank, and

Lena Bank Lena or LENA may refer to: Places * Léna Department, a department of Houet Province in Burkina Faso * Lena, Manitoba, an unincorporated community located in Killarney-Turtle Mountain municipality in Manitoba, Canada * Lena, Norway, a village in � ...

Biology

Marbled rockcod females become sexually mature at about six years of age. Along with mature males they move into the deeper water of the

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 ...

. Spawning takes place once a year and the young fish stay mostly in shallow water in the fiords and bays, feeding mainly on zooplankton. Males can live for up to twelve years.

Fisheries

The marbled rockcod was heavily fished by Soviet fishers during the 1960s and 1970s, with catches exceeding 100,000 tonnes in some seasons; it almost disappeared from around South Georgia Island, and by 1980, was depleted throughout the Southern Ocean. It took the population 20 years to show signs of recovery.

References

* Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd, Auckland, New Zealand 1982) {{DEFAULTSORT:rockcod, marbled

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 ...

Fish of the Southern Ocean Fauna of the Crozet Islands Fauna of the Kerguelen Islands Fauna of Heard Island and McDonald Islands

Taxa named by John Richardson (naturalist)