Alloteuthis media

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Alloteuthis media
Loligo media Merculiano.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Myopsida
Family: Loliginidae
Genus: Alloteuthis
Species:
A. media
Binomial name
Alloteuthis media
(Linnaeus, 1758) [2]
Synonyms [2]
  • Alloteuthis medius(Linnaeus, 1758)
  • Loligo marmorae Vérany, 1839
  • Loligo parvaFroriep, 1806)
  • Loligo urceolata Risso, 1854
  • Loligo urceolatusRisso, 1854
  • Sepia mediaLinnaeus, 1758

Alloteuthis media, the midsize squid or little squid, is a species of squid in the family Loliginidae from the eastern Atlantic and the Mediterranean Sea. [1] [3] It is generally a by-catch species in trawl fisheries, although there is an active fishery in the western Mediterranean. [1]

Contents

Description

Alloteuthis media is hard to tell apart from Alloteuthis subulata . The arms and tentacles of A. media are proportionately slender compared to A. subulata but the two species are best separated by the lateral edge of the mantle, which in A. media extends into a short pointed tail of up to 10mm in length in adults. It grows to a total body length of 200 mm long, with a maximum mantle length of 120mm and the females being larger than the males, [4] with the length of the heart-shaped fins, including the tail, is less than a half the length of the mantle. The hear shape of the fins is produced by their convex anterior ends and then their narrowing posterior edges which become part of the pointed tail. [3] The tentacular club is broad and the diameter of the largest of the suckers in the club is 9–14 % of the width of head. The pairs of suckers in the centre of the club are attached at almost right angles to the axis of the club. [5] In males the hectocotylus is on the Left ventral arm which typically has 11 normal suckers in a ventral row (plus or minus 1), with papillae towards the tip. [6] Sexual maturity is reached in females when they attain about 95mm in length and 55mm in males. [4]

Distribution

Alloteuthis media occurs in the eastern North Atlantic Ocean and the Mediterranean Sea, reported as having a southern limit at Cape Blanc, [5] around 20°N, and a northern one at 60°N in the eastern Atlantic. It is rare in the North Sea with records from the Irish Sea and English Channel on the late 19th and early 20th Centuries. More recently it has not been recorded north of the Iberian Peninsula In the Mediterranean Sea it is widespread and its distribution includes the Sea of Marmara. [6]

Biology

Alloteuthis media is found over occurs on sandy and muddy substrates and prefers waters between 0 and 200m in depth in coastal areas and over the continental shelf, although a maximum depth of 500m has been recorded. It undertakes seasonal migrations between offshore and coastal waters, similar to other neritic species of squid. Spawning is continuous in the western Mediterranean but peaks of mature adults can be discerned, the early on in February when large individuals can be found at depths of 150–200m and these begin to move into shallow to spawn over sandy substrates in March and April, spawning occurs to a lesser among beds of Posidonia sea grass. The later spawning group, is made up of smaller individuals than the earlier group and they migrate onshore during June and July and spawn later in the year. Depending on the water temperature the squid return to deeper waters by late autumn. In the northern Tyrrhenian Sea there are also two peaks of spawning activity, the early one in May and the later in September. Sexual maturity is attained at a variety of size ranges, as seen in other Mediterranean cephalopods, with the eastern populations maturing at smaller mantle lengths than the western. In the eastern Mediterranean the smallest mature females have a mantle length of 37mm, the smallest mature males have one of 32mm while in the western part of that sea the smallest mature females have mantle lengths of 80 mm while that of the smallest mature females measures 50 mm. Females in the eastern basin lay more eggs than those in the west and the eggs they lay are larger which suggests that this species has a higher reproductive productivity in the eastern Mediterranean compared to the western. The male's spermatophores vary between 2.3 and 3.4mm in length and each male bears no more than 170 spermatophores. The females lay the eggs several batches and they are held in short, gelatinous capsules, similar to the capsules of Loligo vulgaris , but less robust and transparent rather than opaque. [6] The egg clusters, each containing up to 1400 eggs, [4] are adhered to hard objects on the sea bed such as shells, corals and stones). Alloteuthis media is a predator which uses crustaceans, molluscs and small fishes as prey. Their life cycle is estimated to be around a year for males and eighteen months for females. [6]

Taxonomy

Recent molecular analyses suggest that Alloteuthis media and A. subulata may be conspecific and that they are the extreme ends of a morphological gradient. [4] In which case the name Alloteuthis media applied by Carl Linnaeus in his Systema Naturae in 1758 would have priority over Jean Baptiste Lamarck's A. subulata which dates from 1798. [2] However, further analyses suggest that these are indeed two sister species which can be reliably separated by the size of the central suckers of the tentacular club and that in fact there is a genetic divergence between the Atlantic and the Mediterranean populations of A. media. [6]

Fisheries

Alloteuthis media is normally a bycatch in trawl fisheries for other species but it is marketed throughout most of the Mediterranean with other Alloteuthis species. In the western Mediterranean it is actively fished for in a trawl fishery and in the winter it is captured at depths of 150m to 200m and from between 50m and 150m in spring, summer and autumn. Its seasonal abundance varies widely, but there is little annual variation. Commercial interest in this species varies according to location and the catch is marketed in both fresh and frozen forms. [6]

Related Research Articles

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Myopsida is one of the four orders of squid. It consists of two families: the monotypic Australiteuthis and the diverse and commercially important Loliginidae. Some taxonomists classify this taxon as a suborder of the order Teuthida, in which case it is known as Myopsina. This reclassification is due to Myopsina and Oegopsina not being demonstrated to form a clade.

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

The European squid or common squid is a large squid belonging to the family Loliginidae. It occurs abundantly in coastal waters from the North Sea to at least the west coast of Africa. This species lives from sea level to depths of 500 m (1,600 ft). Its mantle is up to 40 cm (16 in) long. The species is extensively exploited by commercial fisheries.

<i>Doryteuthis opalescens</i> Species of Cephalopoda

Doryteuthis opalescens, the opalescent inshore squid or market squid, is a small squid in the family Loliginidae. It is a myopsid squid, which is the near shore group and that means that they have corneas over their eyes. The species lives in the eastern Pacific Ocean from Mexico's Baja California peninsula to Alaska, United States, and as an inshore squid it can be found with a range of 200 miles (320 km) off the coast.

<i>Australiteuthis</i> Genus of squids

A. aldrichi is a small species of squid found in northern Australian waters. The species was described by Chung Cheng Lu in 2005 based on specimens collected in the inshore waters of Northern Australia. The largest known individual of this species is a mature female measuring 27.6 mm (1.09 in) in mantle length (ML). The holotype is a mature male of 21.3 mm (0.84 in) ML. A live specimen of A. aldrichi has yet to be recorded. A. aldrichi is a member of the class Cephalopoda and part of the subclass Coleodia. Within this class there are two orders, the Myopsida and Oegopsida, which both fall under the superorder Decapodiformes. A. aldrichi falls under the order of Myospida, and is the only member of its genus, Australiteuthis, and family, Australiteuthidae.

<i>Sepiola atlantica</i> Species of mollusc

Sepiola atlantica, also known as the Atlantic bobtail, is a species of bobtail squid native to the northeastern Atlantic Ocean and the Mediterranean Sea.

<i>Thysanoteuthis rhombus</i> Species of cephalopod known as the diamond squid or diamondback squid

Thysanoteuthis rhombus, also known as the diamond squid,diamondback squid, or rhomboid squid, is a large species of squid from the family Thysanoteuthidae which is found worldwide, throughout tropical and subtropical waters. T. rhombus is given its name for the appearance of the fins that run the length of the mantle. They are a fast growing species with a lifespan of approximately 1 year. The diamond squid is the only cephalopod species known to be monogamous. T. rhombus often preys on fish and other small cephalopods at varying water depths. This species is commercially fished in Japan, specifically in the Sea of Japan and Okinawa.

<i>Alloteuthis subulata</i> Species of squid

Alloteuthis subulata, the European common squid, is a species of squid in the family Loliginidae.

The neon flying squid, sometimes called the red flying squid, akaika, and red squid is a species of large flying squid in the family Ommastrephidae. They are found in subtropical and temperate oceanic waters globally.

<span class="mw-page-title-main">Bigfin reef squid</span> Species of squid

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<i>Illex coindetii</i> Species of squid

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<i>Sepia elegans</i> Species of cuttlefish

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<i>Sepia orbignyana</i> Species of cuttlefish

Sepia orbignyana, the pink cuttlefish, is a species of small cuttlefish from the family Sepiidae. It is occurs in the temperate and tropical waters of the eastern Atlantic Ocean.

Afrololigo mercatoris, commonly known as the Guinean thumbstall squid, is a small species of squid in the family Loliginidae from the eastern central Atlantic Ocean. It is the only species in the monotypic genus Afrololigo.

Loliolus is a genus of squid from the family Loliginidae from the Indo-Pacific region. The genus is divided into two subgenera Loliolus and Nipponololigo. They are small squids of less than 150mm in mantle length which have an expanded tentacular club. This club has 4 series of suckers. The sucker rings have plate-like teeth which are square in shape all around them. The males' hectocotylus has a ventral crest which is created by the fusion of the protective membrane with the ventral series of papillae and this crest completely obscures the conical shape of the papillae. The mantle is rounded posteriorly and lacks the posterior tail-like lobe while the fins are positioned on the rear of the mantle and extend to the posterior tip of the mantle. Their eggs are small and the males' spermatophore has a short cement body. They do not possess photophores. The two subgenera are distinguished by the hectocotylus which in Loliolus encompasses the entire arm and there are no unmodified suckers while in Nipponololigo the arm is only partly hectocotylsed and has normal suckers at its base.

<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.

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<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 Oceans.

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

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<i>Rossia</i> Genus of molluscs

Rossia is a genus of 10 species of benthic bobtail squid in the family Sepioidae found in all oceans. They live at depths greater than 50 m (164 ft) and can grow up to 9 cm in mantle length. This genus was first discovered in 1832 by Sir John Ross and his nephew James Clark Ross in the Arctic Seas, showing a resemblance to another genus under the same family, Sepiola. After returning from their expedition, Sir Richard Owen officially classified Rossia to be a new genus, naming it after Sir John and James Clark Ross.

References

  1. 1 2 3 Allcock, A.L.; Taite, M. (2019). "Alloteuthis media". IUCN Red List of Threatened Species . 2019: e.T163027A964854. doi: 10.2305/IUCN.UK.2019-2.RLTS.T163027A964854.en . Retrieved 3 October 2022.
  2. 1 2 3 Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O, eds. (2022). "Alloteuthis media (Linnaeus, 1758)". MolluscaBase. World Register of Marine Species . Retrieved 3 October 2022.
  3. 1 2 Wilson, E. (1999). Tyler-Walters H.; Hiscock K. (eds.). "Little squid (Alloteuthis media)". Marine Life Information Network (MarLIN). The Marine Biological Association of the UK. Retrieved 22 February 2018.
  4. 1 2 3 4 Vecchione, Michael; Richard E. Young (2010). "Alloteuthis media (Linnaeus 1758) Midsize squid". The Tree of Life Web Project. Retrieved 22 February 2018.
  5. 1 2 M.J. de Kluijver; S.S. Ingalsuo; R.H. de Bruyne. "Alloteuthis media". Mollusca of the North Sea. ETI Bioinformatics: Marine Species Identification Portal. Retrieved 22 February 2018.
  6. 1 2 3 4 5 6 Jereb, P.; Vecchione, M.; Roper, C.F.E. (2010). "Family Loliginidae". In Jereb, P.; Roper, C.F.E. (eds.). Cephalopods of the world. An annotated and illustrated catalogue of cephalopod species known to date. Volume 2. Myopsid and Oegopsid Squids. Rome: Food and Agriculture Organization of the United Nations. pp. 48–49. ISBN   978-92-5-106720-8.
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