The bald notothen (''Pagothenia borchgrevinki''), also known as the bald rockcod, 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.
Taxonomy
The bald notothen was first formally
described in 1907 as ''Trematomus borchgrevinki'' by the Belgian-born British
ichthyologist
Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of Octobe ...
George Albert Boulenger
George Albert Boulenger (19 October 1858 – 23 November 1937) was a Belgian-British zoologist who described and gave scientific names to over 2,000 new animal species, chiefly fish, reptiles, and amphibians. Boulenger was also an active botani ...
with the
type localities given as at the surface at
Duke of York Island and at
Cape Adare
Cape Adare is a prominent cape of black basalt forming the northern tip of the Adare Peninsula and the north-easternmost extremity of Victoria Land, East Antarctica.
Description
Marking the north end of Borchgrevink Coast and the west e ...
.
The
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
honours
Carsten Egeberg Borchgrevink
Carsten Egeberg Borchgrevink (1 December 186421 April 1934) was an Anglo-Norwegian polar explorer and a pioneer of Antarctic travel. He inspired Sir Robert Falcon Scott, Sir Ernest Shackleton, Roald Amundsen, and others associated with the He ...
who commanded the
British Southern Cross Antarctic Expedition (1898–1900), during which
types were collected.
Description
The bald notothen attains a maximum
total length around , it is yellow with dark spots and irregular crossbars. Its
dorsal and
caudal fins may occasionally also be spotted.
[
]
Distribution, habitat and biology
The bald notothen is found in the Southern Ocean where it has been recorded from the Weddell Sea, the Ross Sea, the Davis Sea
Davis Sea is an area of the sea along the coast of East Antarctica between West Ice Shelf in the west and the Shackleton Ice Shelf in the east, or between 82° and 96°E. The name "Davis Sea" appears in most leading geographically authoritati ...
, in Vincennes Bay
Vincennes Bay is a large V-shaped bay, 105 km (65 mi) wide at its entrance between Cape Nutt and Cape Folger in Antarctica, marked by several large, steep glaciers near its head, lying along Knox and Budd Coasts. It was photographed f ...
, and around the Budd Coast, 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 ...
, South Orkneys, and South Shetland Islands. It can be found at depths from the surface to , though it is much rarer below . This species is cryopelagic and is often found along the under surfaces of ice foraging for prey such as sympagic
A sympagic environment is one where water exists mostly as a solid, ice, such as a polar ice cap or glacier. Solid sea ice is permeated with channels filled with salty brine. These briny channels and the sea ice itself have its ecology, referred t ...
copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
s and krill. In turn, it is known to be preyed upon by the ploughfish
The ploughfish (''Gymnodraco acuticeps'') is a species of Antarctic dragonfish native to the Southern Ocean around Antarctica. It is found at depths of from over the Antarctic continental shelf. This species is the only known member of its genus ...
(''Gymnodraco acuticeps'') and the Antarctic toothfish
The Antarctic toothfish (''Dissostichus mawsoni'') is a large, black or brown fish found in very cold (subzero) waters of the Southern Ocean near Antarctica. It is the largest fish in the Southern Ocean, feeding on shrimp and smaller fish, and pr ...
(''Dissostichus mawsoni''). Antifreeze proteins in its blood prevent it freezing in the subzero water temperatures of Antarctica. The bald notothen is adapted to life in the water column as the shape and flatness of the trunk may streamline the fish and reduce drag. the pelvic
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton).
The ...
and 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 ...
s do not have the adaptations for substrate contact borne by related benthic species. There are silvery reflective layers, called ''strata argentea'' below the skin and in the this provides camouflage when the fish is seen against the background of platelet ice. The retina had numerous cones suggesting that the eye is able to function during the day and at night.
Fisheries
The bald notothen is of no interest to commercial fisheries.
References
{{Taxonbar, from=Q924372
Bald notothen
The bald notothen (''Pagothenia borchgrevinki''), also known as the bald rockcod, 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.
Taxonomy
The bald ...
Fish of the Southern Ocean
Fish of Antarctica
Fish described in 1902
Taxa named by George Albert Boulenger