Gonatopsis borealis

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Gonatopsis borealis
Gonatopsis borealis.jpg
Gonatopsis borealis museum specimen from National Chung Hsing University, Department of Life Science
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Oegopsida
Family: Gonatidae
Genus: Gonatopsis
Species:
G. borealis
Binomial name
Gonatopsis borealis
Sasaki, 1923 [2]

Gonatopsis borealis, the Boreopacific armhook squid, is a species of squid from the North Pacific Ocean. It is a member of the family Gonatidae. It is an abundant species which is currently caught mainly as a bycatch by fishing boats targeting other quarry. It is an important prey species for many commercially important species of fish, as well as for marine mammals.

Contents

Description

Gonatopsis borealis is a medium-sized squid. There are three morphs: large bodied, slender bodied and small bodied; these may be separate taxa, but this needs more research. [1] The main characteristics which distinguish this species from closely related species are that it has transverse rows of seven teeth on its radula, rather short blunt-tipped arms which have four rows of suckers near their tips, and a muscular mantle. [3] The muscular arms are 40-45% of the mantle length and some are longer than others, arms III have well developed aboral keels. Arms I to III have 2 middle series of hooks and 2 marginal series of suckers; arm IV has no hooks and four series of suckers. The development of hooks on the arms does not occur until the animal reaches a mantle length of 35 to 45 mm. [4] There is no hectocotylus. The lose their tentacles at the paralarva stage. They have large eyes and a nuchal crest which has four longitudinal nuchal folds of skin on either side of it. [3] The muscular mantle is cylindrical and tapers to a blunt posterior. The muscular fins are short (40 to 45% of the mantle length), wide (65 to 80% of mantle length) [4] and rhomboid in shape. There is no tail. The skin on the mantle is dark reddish or purplish brown in colour and there are no photophores. Mature males grow to a mantle length of 270mm ML while mature females reach mantle lengths of 330mm. [3]

The paralarvae are distinguished by the pattern of chromatophores on the dorsal part of the head. This consists of three transverse rows of chromatophores with a single chromatophore in the front row, two in the middle row and three in the rear row. They also have 6-10 chromatophores in the dorsal surface of the mantle. [3]

Distribution

Gonatopsis borealis is found in the North Pacific Ocean, where its range extends from northern Japan at a latitude of roughly 37°N to 40°N through the Okhotsk Sea, Bering Sea all along the Aleutian Islands into the Gulf of Alaska, south along the western coast of North America to California, even reaching Baja California at a latitude of 20°N. [4] The type specimen was taken off Hokkaido, some 15–30 miles (24–48 km) east of Kushiro. [3]

Habitat and biology

Gonatopsis borealis is an oceanic speciesand it is one of the most widely distributed and abundant species of the family Gonatidae. It can be found in cold temperate waters, where it can occur from the surface to the mesopelagic zone, even reaching into the bathypelagic zone. It undertakes a diel vertical migration, moving up the water column at night, and for forming very large aggregations between the Spring and the early autumn, especially in both the eastern and western parts of its range. The abundance of G. borealis is indicated by it accounting for up to 68% of squid catches in the Okhotsk Sea during the summer months. G. borealis is found in epipelagic, mesopelagic and bathypelagic depths from the surface to 1500m. It has a benthic habit at 200 to 1 375m, but it is most numerous in the midwater realm, with maximum abundance occurring at 300 to 500m, while only a few single specimens are caught below 1000 m (probably having been caught at much shallower depths while the open nets were retrieved through their zone of most abundance). Off California there were no specimens of any age recorded during the day at depth of less than 300m, and 90% of specimens collected during daylight were from 400 to 700m. By contrast, specimens occurred mainly at 100 to 500m, principally 300 to 400m at night. Smaller animals undertook the diel migration to the surface layers earlier than the larger ones. They also returned to depths sooner, possibly a behavioural adaptation to avoid the larger cannibalistic adults. This species preys on a diverse variety of pelagic crustaceans such as euphausiids, hyperiid amphipods and copepods, as well as fishes and other squid. They live for at least a year. Their predators include fish such as salmonids, walleye Pollock, pomfret, albacore and grenadiers, as well as the larger squid Berryteuthis magister and cannibalistic G. borealis. Other predators include seabirds, seals, sea lions, dolphins and toothed whales, such as sperm whale and pilot whales. [4]

Fisheries

Gonatopsis borealis is an abundant species. In the Sea of Ohotsk in the summer months there is estimated to be a biomass of this species ranging from 278,000 tonnes to 500,000 tonnes, with estimates of 209,000 tonnes in the western Bering Sea, 285,000 tonnes off the western Kamchatka coast, and 100,000 tonnes in waters around the Kuril Islands. [1] The large morph of this species form the major part of any catch. It is caught as bycatch with jigs, and substantial numbers are caught in drift gillnets which are set to take salmonids and the neon flying squid (Ommastrephes bartramii). The meat of this species is said to be highly palatable, and as it is an abundant species it is thought to have a high potential to support fisheries. However, it is the principal prey for many of valuable species of fish, and this ecological role is perhaps more important to local fisheries than any development of a fishery to target this species. [4]

Taxonomy

Gonatopsis borealis differs from other members of the genus Gonatopsis in having seven rather than five rows of teeth on the radula. Kir Nesis proposed that it be placed in its own subgenus Boreoteuthis. Subsequently, this has been treated by some authorities as a separate genus. The generic status of G. borealis is yet to resolved, as is the taxonomic status of the three size morphs which have been recorded. [3]

In the Asiatic part of its range, two distinct populations are found, a more northerly population which matures at less than 180mm mantle length, and a more southern population found south of latitude 45°N to 47°N, which reached sexual maturity at larger than 220mm mantle length. The two populations are found sympatrically in the waters off the Kuril Islands. [4]

Related Research Articles

<span class="mw-page-title-main">Squid</span> Superorder of cephalopod molluscs

A squid is a mollusc with an elongated soft body, large eyes, eight arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin.

<i>Bathyteuthis</i> Genus of squids

Bathyteuthis is the singular genus of squid in the family Bathyteuthidae, encompassing three species.

<span class="mw-page-title-main">Gonatidae</span> Family of squids

The Gonatidae, also known as armhook squid, are a family of moderately sized squid. The family contains about 19 species in three genera, widely distributed and plentiful in cold boreal waters of the Pacific Ocean. At least one species is known from Antarctic waters, and two from the North Atlantic. The genus Eogonatus was created for the species known as Eogonatus tinro because it did not have hooks on the tentacular club and it has 5 rows of teeth on the radula. Molecular studies in allozymes and mitochondrial DNA have indicated that this species nests within the genus Gonatus, although other authorities treat it as a synonym of Gonatopsis okutanii.

<i>Berryteuthis magister</i> Species of squid

Berryteuthis magister, also known as the magister armhook squid, commander squid or schoolmaster gonate squid, is a medium-sized squid in the family Gonatidae. It is found in cold, high latitude waters of the North Pacific where it is among the most numerous squid species recorded.

<i>Doryteuthis plei</i> Species of squid

Doryteuthis plei, also known as the slender inshore squid or arrow squid, is a medium-sized squid belonging to the family Loliginidae. It occurs abundantly in coastal waters of the Atlantic Ocean, from Argentina northward to North Carolina.

<i>Sandalops melancholicus</i> Species of squid

Sandalops melancholicus, the sandal-eyed squid or melancholy cranch squid, is a small species of glass squid. It is known to reach a mantle length of 11 cm (4.3 in). It is distributed in the tropical and subtropical oceans around the world. It is the only species in the genus Sandalops but some authorities suggest that this may be a species complex rather than a monotypic genus.

<i>Gonatus onyx</i> Species of squid

Gonatus onyx is in the class Cephalopoda and in the phylum Mollusca. It is also known as the clawed arm hook squid or the black-eyed squid. It got these names from the characteristic black eye and from its two arms with clawed hooks on the end that extend a bit further than the other arms. It is a squid in the family Gonatidae, found most commonly in the northern Pacific Ocean from Japan to California. They are one of the most abundant cephalopods off the coast of California, mostly found at deeper depths, rising during the day most likely to feed.

<i>Enoploteuthis</i> Genus of squids

Enoploteuthis is a genus of squid in the family Enoploteuthidae. The species of Enoploteuthis are most easily recognised by having a larger tail when compared to the other genera in the Enoploteuthidae. The tail's size is emphasised by not having the fins extending along its sides. In related genera there is a narrow extension of the fins along the tail. Other characteristics include the presence of suckers on the distal portion of arms IV where there at no photophores present; the tentacular club has two rows of hooks and no marginal suckers; on the buccal crown there are typical chromatophores on the aboral surface but on the oral surface there may be some light skin pigmentation. They have 9-10 photophores on the eye and they have complex photophores in the skin. In the females the Spermatangia receptacles are at the posterior junction of muscles used to retract the funnel and the muscles which retract the head. Enoploteuthis differs from other genera of the Enoploteuthidae in having two rather than three types of photophores in its integument and these are on the ventral areas of the head, funnel and mantle. All species of Enoploteuthis which have been studied have the most complex type of photophoreand seems to be a distinctive characteristic of this genus. Enoploteuthis contains the largest species in the family, attaining a mantle length of 130mm.

<i>Teuthowenia megalops</i> Species of squid

Teuthowenia megalops, sometimes known as the Atlantic cranch squid, is a species of glass squid from the subarctic and temperate waters of the northern Atlantic Ocean. They are moderately sized squid with a maximum mantle length of 40 cm (16 in). Their very large eyes are the source for the specific name megalops. Like other members of the genus Teuthowenia, they are easily recognizable by the presence of three bioluminescent organs (photophores) on their eyeballs.

<i>Galiteuthis glacialis</i> Species of squid

Galiteuthis glacialis is a species of glass squid from the Antarctic Convergence. It is in the cranchiidae family and subfamily taoniinae. They are endemic to the Antarctic and are found in the Southern Ocean, around the Weddell Sea and the South Shetland Islands. Galiteuthis glacialis are one of the most plentiful and widely dispersed species of Antarctic squid. These squids are found in the mesopelagic and bathypelagic layers of the open ocean and demonstrate vertical migration. They can reach a maximum mantle length of 500 mm (0.5m).

Brachioteuthis riisei is a species of squid in the family Brachioteuthidae.

Taonius borealis is a glass squid belonging to the genus Taonius. It is found in the North Pacific Ocean, ranging from Japan to southern California.

<i>Taonius belone</i> Species of squid

Taonius belone is a glass squid belonging to the genus Taonius from the family Cranchiidae. It occurs in the northern subtropical and in the tropical or equatorial waters of the Pacific Ocean and the Indian Ocean.

Gonatopsis is a genus of squid from the family Gonatidae. They are characterised by the loss of their tentacles by the time they have reach the subadult stage. They have arms which have two series of hooks along the midline of the oral surface arms, the radula has five or seven teeth, the mantle can be muscular or flabby, fins are rhomboid or arrow shaped and they lack photophores. They are found in the North Pacific.

Gonatopsis okutanii is a species of squid from the family Gonatidae from the northern Pacific Ocean. It is of uncertain taxonomic status, the presence of remnant tentacles on spent females indicate that this species does not belong in the genus Gonatopsis and the differences between this species and Gonatus makodai have led to some authorities stating that G. okutanii is a junior synonym of Eogonatus tinro. However the World Register of Marine Species still recognises Gonatopsis okutanii as the valid name for this taxon.

Gonatopsis japonicus is a species of squid from the family Gonatidae. This species is restricted to the western North Pacific in the seas around the Japanese Archipelago.

Eucleoteuthis is a monotypic genus of squid from the family Ommastrephidae; the only species is Eucleoteuthis luminosa, the striped flying squid or luminous flying squid.

<i>Ornithoteuthis antillarum</i> Species of squid

Ornithoteuthis antillarum, the Atlantic bird squid, is a species of flying squid from the family Ommastrephidae which is found in the warmer waters of the Atlantic Ocean. This species is an important component of the diet of many species of fish and of cetaceans. It is taken as a bycatch in fisheries but has the potential to be commercially important if appropriate fishing methods can be developed.

<span class="mw-page-title-main">Antarctic flying squid</span> Species of squid

The Antarctic flying squid is a species of squid from the subfamily Todarodinae of the family Ommastrephidae, a family of pelagic squid from the order Oegopsida. It has a circumglobal distribution in the seas around the lower latitudes of the Southern Ocean.

<span class="mw-page-title-main">European flying squid</span> Species of squid

The European flying squid is a species of squid from the continental slope and oceanic waters of the eastern Atlantic Ocean and the Mediterranean Sea. It is the type species of the genus Todarodes, the type genus of the subfamily Todarodinae of the pelagic squid family Ommastrephidae. It is a species which is targeted by some fisheries, although it is more often a bycatch.

References

  1. 1 2 3 Barratt, I. & Allcock, L. (2014). "Gonatopsis borealis". The IUCN Red List of Threatened Species . 2014: e.T162930A954587. doi: 10.2305/IUCN.UK.2014-1.RLTS.T162930A954587.en . Downloaded on 05 March 2018.
  2. ↑ Julian Finn (2016). "Gonatopsis borealis Sasaki, 1923". World Register of Marine Species . Flanders Marine Institute . Retrieved 5 March 2018.
  3. 1 2 3 4 5 6 Tsunemi Kubodera (2015). "Gonatopsis borealis Sasaki, 1923". Tree of Life Web Project.
  4. 1 2 3 4 5 6 P. Jereb; C.F.E. Roper, eds. (2010). Cephalopods of the World an Annotated and Illustrated Catalogue of Cephalopod Species Known to Date Volume 2 Myopsid and Oegopsid Squids (PDF). Food and Agriculture Organization Rome. pp. 215–216. ISBN   978-92-5-106720-8.
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