Grey rockcod

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Grey rockcod
Lepidonotothen squamifrons, the grey rockcod.gif
A drawing of Lepidonotothen squamifrons, the grey rockcod by J.C.Hureau
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Nototheniidae
Genus: Lepidonotothen
Balushkin, 1976
Species:
L. squamifrons
Binomial name
Lepidonotothen squamifrons
(Günther, 1880)
Synonyms [1]
  • Notothenia kempi Norman, 1937
  • Notothenia squamifronsGünther, 1880
  • Notothenia squamifrons squamifronsGünther, 1880
  • Notothenia macrophthalmaNorman, 1937
  • Notothenia kempiNorman, 1937
  • Lepidonotothen kempi(Norman, 1937)
  • Lepidonotothen macrophthalma(Norman, 1937)
  • Notothenia brevipectoralis Hureau, 1966
  • Notothenia squamifrons atlantica Permitin & Sazonov, 1974

The grey rockcod (Lepidonotothen squamifrons), also known as the grey notothen, stripe-eyes notothen or stripe-eyed 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. The grey rockcod feeds mainly on macrozooplankton and is of minor importance to commercial fisheries. It is the only species in the genus Lepidonotothen.

Contents

Taxonomy

The grey rockcod was first formally described in 1880 as Notothenia squamifrons by the German-born British ichthyologist Albert Günther with the type locality given as Kerguelen Island. The type was collected during the Challenger Expedition. [2] In 1976 the Russian ichthyologist Arkady Vladimirovich Balushkin placed it in the genus Lepidonotothen, [3] this genus is currently regarded as monotypic with this species as its sole member. [4] However, other authorities regard Lepidonotothen kempi as a valid species. [3] Some authorities place this taxon in the subfamily Nototheniinae, [5] but the 5th edition of Fishes of the World does not include subfamilies in the Nototheniidae. [6] The name of the genus is a compound of lepido meaning “scaled”, an allusion to the scales on the top of the head and jaws of this species, and notothen, indicating that it is a notothen. The specific name is a combination of squamis which means "scale" and frons meaning "forehead", a reference to the head being covered with small scales almost as far as the nostrils. [7]

Description

The grey rockcod has an oblong body that is compressed towards the tail. It has dorsally positioned eyes that may bulge above the dorsal profile of the head, the eyes are separated by a narrow area that has a width less than the diameter of the eye. The pores in the sensory canal on the head are small. The mouth is small and does not extend to the middle of the eye and there are no large canine-like teeth. The head is almost completely scaled. There are two lateral lines, an upper and a middle line, both consisting of tubed scales. Its pectoral fins are smaller than the pelvic fins. There are 15–17 branched rays in the rounded or truncate caudal fin. [5] The first dorsal fin has 4–5 spines, the second dorsal fin has 36–37 soft rays while the anal fin contains 29–33 soft rays. This species attains a maximum total length of 55 cm (22 in), although 35 cm (14 in) is more typical. [1] The colour of the body is greyish above marked with 9 non-uniform, wide, dark bars that join on the underside. There is a dark stripe along the front edge of the snout extending to the lower margin of the preoperculum with a second dark stripe from the lower orbit to the angle of the preopeculum. There are two dark stripes on the upper part of the orbit. The posterior part of the first dorsal fin is blackish. [5]

Distribution and habitat

The grey rockcod is found in the Southern Ocean a far north as the Falkland Islands and the Burdwood Bank, [5] South Georgia Island and Bouvet Island. This species has also been recorded from sub-Antarctic islands and the far south of the Indian and Pacific Oceans. It is a benthopelagic fish which is found at depths of 10 to 900 m (33 to 2,953 ft) but it is most frequent at depths of 195 to 312 m (640 to 1,024 ft). [1]

Biology

The grey rockcod is the dominant fish species in the waters off the Kerguelen Islands, which is where the greatest plankton productivity in the Southern Ocean takes place, and this population has one of the fastest rates of growth. These fish reach sexual maturity at lengths of 34–36 cm (13–14 in) at ages of 8 or 9 years old, faster than any other population which has been studied. The fish in this population also attain the larger known sizes than fish from the Crozet Islands or Lena Seamounts, although South Georgia is where the largest fish have been recorded and where the rate of growth is faster than at Kerguelen. [5]

Spawning occurs at the end of October in the Kerguelen and Crozet islands while in South Georgia it happens in February. Embryonic development has been estimated to takes around 2 to 3 months. In South Georgia, postlarvae which were around 30 mm (1.2 in) in standard length were caught in December. Females at Kerguelen could lay between 48,650 and 196,150 eggs in a season at total lengths between 28 and 44 cm (11 and 17 in) while at South Georgia they can lay 69,000–185,000 at total lengths between 35 and 50 cm (14 and 20 in). The eggs have a diameter of 1.4 to 1.7 mm (0.055 to 0.067 in). [5]

This species feeds mainly on larger zooplankton, mostly crustaceans, cnidarians and salps, as well as fishes found in the water column. [5]

Fisheries

The grey rockcod is exploited by commercial fisheries. In the Kerguelen Islands only the marbled rockcod (Notothenia rossii) and the mackerel icefish (Champsocephalus gunnari) are a more important catch than this species. However, it is of much less importance to fisheries around South Georgia. [5]

Related Research Articles

<span class="mw-page-title-main">Nototheniidae</span> Family of fishes

Nototheniidae, the notothens or cod icefishes, is a family of ray-finned fishes, part of the suborder Notothenioidei which is traditionally placed within the order Perciformes. They are largely found in the Southern Ocean.

<span class="mw-page-title-main">Marbled rockcod</span> Species of fish

The marbled 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, where it can be found at depths from 5 to 350 m. This is a commercially important species.

<i>Notothenia</i> Genus of fishes

Notothenia is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes with the species in this genus often having the common name of rockcod. They are native to the Southern Ocean and other waters around Antarctica.

<span class="mw-page-title-main">Painted notie</span> Species of fish

The painted notie, or painted notothen, 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.

<i>Paranotothenia magellanica</i> Species of fish

Paranotothenia magellanica, also known as Magellanic rockcod, Maori cod, blue notothenia or orange throat notothen, 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. "Maori chief" and "black cod", sometimes used for this species, usually refer to fishes from the related genus Notothenia. Being a perciform fish, it is unrelated to the true cods of the order Gadiformes. This species is commercially important as a food fish.

<i>Trematomus</i> Genus of fishes

Trematomus is a genus of marine ray-finned fishes, belonging to the family Nototheniidae, the notothens or cod icefishes. These fishes occur in the Southern Ocean.

<span class="mw-page-title-main">Longfin icedevil</span> Species of fish

The longfin icedevil, also known as the threadfin pinhead, 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 down to 850 metres (2,790 ft). This species grows to a length of 42 centimetres (17 in) TL. This species is the only known member of its genus and is of no interest to commercial fisheries.

<i>Gobionotothen</i> Genus of fishes

Gobionotothen is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes. They are native to the Southern Ocean.

<i>Lindbergichthys</i> Genus of fishes

Lindbergichthys is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes.

<span class="mw-page-title-main">Toad notie</span> Species of fish

The toad notie, or toad notothen, is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the Indian sector of the Southern Ocean.

Nototheniops is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes. The species in this genus are native to the Southern Ocean.

<i>Paranotothenia</i> Genus of fishes

Paranotothenia is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes. These fishes are native to the Southern Ocean.

<i>Patagonotothen</i> Genus of fishes

Patagonotothen is a genus of marine ray-finned fishes, belonging to the family Nototheniidae, the notothens or cod icefishes. They are native to the southeast Pacific Ocean, southern Atlantic Ocean and the Southern Ocean.

<i>Notothenia coriiceps</i> Species of fish

Notothenia coriiceps, also known as the black rockcod, Antarctic yellowbelly rockcod, or Antarctic bullhead notothen, is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is widely spread around the Antarctic continent. Like other Antarctic notothenioid fishes, N. coriiceps evolved in the stable, ice-cold environment of the Southern Ocean. It is not currently targeted by commercial fisheries.

<i>Lindbergichthys nudifrons</i> Species of fish

Lindbergichthys nudifrons, the yellowfin rockcod, also known as the yellow notie or the gaudy notothen, is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the Atlantic sector of the Southern Ocean.

<i>Gobionotothen gibberifrons</i> Species of fish

Gobionotothen gibberifrons, the humped rockcod or the humphead notothen, is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the islands of the Scotia Arc, the northern part of the Antarctic Peninsula, and Heard Island in the Southern Ocean. This species inhabits depths of 6-429 m, but is most abundant at depths of 100-400 m, at least around Elephant Island.

<i>Gobionotothen marionensis</i> Species of fish

Gobionotothen marionensis, the lobe-lip notothen, is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the South Georgia and the South Sandwich Islands in the Atlantic Ocean, and the Crozet and Prince Edward Islands in the Indian Ocean.>

Gobionotothen acuta, the triangular rockcod or the triangular notothen, is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the French Southern and Antarctic Lands, the Heard Islands and the Kerguelen Plateau in the Southern Ocean.

<i>Notothenia cyanobrancha</i> Species of fish

Notothenia cyanobrancha, the blue rockcod, bluegillnotothen, or bluegill rockcod, is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the Kerguelen and Heard Islands in the Southern Ocean.

<span class="mw-page-title-main">Stocky rockcod</span> Species of ray-finned fish

The stocky rockcod, also known as the bandtail notothen, is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is found in the Southern Ocean.

References

  1. 1 2 3 Froese, Rainer; Pauly, Daniel (eds.) (2021). "Lepidonotothen squamifrons" in FishBase. June 2021 version.
  2. ↑ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Lepidonotothen". Catalog of Fishes . California Academy of Sciences . Retrieved 21 September 2021.
  3. 1 2 Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Nototheniidae". Catalog of Fishes . California Academy of Sciences . Retrieved 21 September 2021.
  4. ↑ Froese, Rainer and Pauly, Daniel, eds. (2021). Species of Lepidonotothen in FishBase . June 2021 version.
  5. 1 2 3 4 5 6 7 8 H.H. Dewitt; P.C. Heemstra; and O. Gon (1990). "Nototheniidae Notothens". In O. Gon and P.C. Heemstra (eds.). Fishes of the Southern Ocean. South African Institute for Aquatic Biodiversity. ISBN   9780868102115.
  6. ↑ J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. p. 465. ISBN   978-1-118-34233-6.
  7. ↑ Christopher Scharpf & Kenneth J. Lazara, eds. (12 April 2021). "Order Perciformes: Suborder Notothenoididei: Families Bovichtidae, Pseaudaphritidae, Elegopinidae, Nototheniidae, Harpagiferidae, Artedidraconidae, Bathydraconidae, Channichthyidae and Percophidae". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 21 September 2021.
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