Humboldt squid
| Humboldt squid | ||||||||||||
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Humboldt squid ( Dosidicus gigas ) |
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| Scientific name of the genus | ||||||||||||
| Dosidicus | ||||||||||||
| Steenstrup , 1857 | ||||||||||||
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| Dosidicus gigas | ||||||||||||
| ( d'Orbigny , 1835) |
The Humboldt squid ( Dosidicus gigas ), also Humboldt squid , giant arrow squid or giant flying squid , is a pelagic cephalopod from the order of the squid . It is the only species of the thus monotypical genus Dosidicus .
It is widespread on the Pacific coast of North and South America. He got the name "Humboldt squid" from the Humboldt Current, in whose area he lives. He is called "giant flying squid" because of its ability to catapult itself out of the water.
features
Dosidicus gigas is the largest species in the family Ommastrephidae, with a total length of up to 2.5 m, a coat length of 1.2 m and a weight of up to 50 kg. Anatomically he represents the typical image of the squid. Its tube, like the tubes of the other representatives of this order, is elongated and has two lateral fins. In the tube there is no hard Schulp , just a thin, flexible chitin rod , the gladius . Of his 10 arms are two as special tentacles ( tentacles trained), which can be extend quickly to seize prey even from a distance. The arms carry 100 to 200 pairs of suction cups that contain a ring with small teeth. The club-like thickened ends of the tentacles are covered with 49 to 58 rows of suction cups. The tentacles' largest suction cups have four teeth, one tooth in each quadrant, larger.
Humboldt squids have a hard, sharp beak that they use to break the shells of crabs. The 3–7 cm long beak is made of chitin , is transparent to whitish at the proximal end (towards the center of the body) and turns black at the distal end.
The red color of captured animals comes from special color cells ( chromatophores ) in the skin with which they camouflage themselves from hunters, as they usually cannot see red. Another typical feature of cuttlefish is the eponymous ink that is produced in the ink bag and, in the event of danger, is released onto the opponent as a cloud that steals vision through the siphon.
distribution
Dosidicus gigas is endemic to the eastern Pacific , especially the productive waters of the Humboldt and California rivers and the Costa Rica Dome . To the west, the distribution area extends to 140 ° west, where the two ocean currents meet.
Way of life and habitat
Few squids grow as big as the Humboldt squid. The giant squid in the deep sea and the colossal squid in the Antarctic deep sea are much larger, but they spend their lives in the deeper zones of the oceans. The Humboldt squid, on the other hand, lives in the deeper zones of the sea - it occurs down to a depth of 1200 m - also in the near-surface neritic zones. The species spends the bright day at depths of more than 250 m, at night it looks for food in near-surface water and often undertakes vertical migrations from the surface into the depths.
Humboldt squids are large and aggressive animals, cannibalism is common. Attempts by Humboldt squids to attack their conspecifics or even to eat them are documented, among other things, by film material. The Humboldt squid is also famous for its striking red color, which changes into a red-white flashing when aggression occurs. By ejecting a cloud of ink, the squid can fog up the enemy to gain enough time to escape or even scare away the enemy. Despite cannibalism, Humboldt squids live in swarms and also hunt together. They communicate and cooperate with one another. Your communication is amazingly complex. It takes place via visual color signals on their skin, especially between the eyes and on the edges of the fins. Video recordings of a total of 30 Humboldt squids, which scientists created with the help of underwater robots in the Gulf of California, show detailed and complex colored symbols with which the animals could transmit precise messages. The characters are displayed using luminous organs in the skin that illuminate the color pattern above, similar to how the letters are displayed in an e-book reader by the background light. With these abilities, Humboldt squids are an example of the intelligence of cephalopods .
Humboldt squids are voracious and grow extremely quickly. However, like most cephalopods, their life ends after only 1 to 2 years. During this time, however, the squid has grown from a coat length of 1 mm at birth to a coat length of 1 m. The squids feed on animal food, whereby as young animals they mainly eat zooplankton , as adult animals they eat fish such as anchovies , sardines , mackerel and lantern fish as well as crustaceans and other invertebrates. They are the prey of fish, marine mammals and birds.
Squids and people
Because of their size and spectacular appearance, squids are occasionally caught by sport fishermen. In addition, they are also fished commercially and then, in addition to (Latin) American markets, also reach European, e.g. B. in Spain, Russia and France. The most important fishing grounds for Humboldt squids are the Pacific coasts off Chile and Peru and the Gulf of California . The catch was between 642,000 and 895,000 tons per year from 2006 to 2010. To catch the squid, lamps are shone into the water (small, bright lights attract squid), then the squids, which are now gathered in schools around the fishing boat, are pulled out with nets or on lines to which so-called squid jigs are attached drawn to the sea.
When catching angling, care must be taken when loosening the squid jig near the mouth opening, as the powerful beak can injure a careless fisherman and even lose a finger. Due to their threatening size, the Humboldt squids have corresponding names in some countries, such as diablo rojo ( Spanish : red devil ). Large, aggressive groups of Humboldt squids have been known to attack divers or fallen fishermen, with several confirmed deaths.
mass extinction
In February 2019, around 60,000 dead Humboldt squids were washed up on various beaches in the Atacama region (including Playa Bahía Inglesa ) in Chile. At the same time, mass deaths of anchovies and sardines have been observed on other beaches in the region . So far nothing is known about the cause of the mass extinction.
Web links
- Dosidicus at Tree of Life Web Project (ToL).
swell
- Georg Rüschemeyer: Mare - The magazine of the seas, dreiviertel verlag GmbH & Co. KG, Hamburg
- Humboldt Squid - Wikipedia, the free enzyklopedia (the English version of this article)
Individual evidence
- ↑ Theodor CH Cole: Dictionary of food. Spektrum Akademischer Verlag, 2010, ISBN 978-3827419927 , p. 162.
- ↑ a b c William F. Gilly et al. : Spawning by jumbo squid Dosidicus gigas in San Pedro Mártir Basin, Gulf of California, Mexico. In: Marine Ecology Progress Series (MEPS) 313, 2006. ( Online ; PDF; 1.8 MB)
- ^ Georg Rüschemeyer: Mare - The magazine of the seas. dreiviertel verlag GmbH & Co.KG Hamburg in Mare - Die Zeitschrift der Meere No. 62, accessed on May 26, 2012
- ↑ a b c Josafat Marina Ezquerra-Brauer et al .: By-Products From Jumbo Squid (Dosidicus gigas): A New Source of Collagen Bio-Plasticizer? In: Recent Advances in Plasticizers , p. 21 ( Online ; PDF; 1.2 MB)
- ↑ a b Louis D. Zeidberg, Bruce H. Robison: Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific: ( Online )
- ↑ a b c d e W. F. Gilly et al. : Vertical and horizontal migrations by the jumbo squid Dosidicus gigas revealed by electronic tagging. 2006 In: Marine Ecology Progress Series 324 pp. 1-17. ( Online ; PDF; 2.7 MB)
- ^ A b Dosidicus at Tree of Life Web Project (ToL).
- ↑ Russ Vetter et al .: Predatory interactions and niche overlap between mako shark, Isurus oxyrinchus, and jumbo squid, Dosidicus gigas, in the California Current. In: CalCOFI 49, 2008 ( Online ; PDF; 3.7 MB)
- ↑ Jerome Casas, Stephen Simpson: Advances in Insect Physiology. Academic Press, 2010, ISBN 978-0123813893 , p. 104.
- ^ Christian M. Ibáñez, and Luis A. Cubillos: Seasonal variation in the length structure and reproductive condition of the jumbo squid Dosidicus gigas (d'Orbigny, 1835) off central-south Chile. In: Scientia Marina 71. ([Online])
- ↑ J. Field, K. Baltz, J. Philips, W. Walker: Range expansion and trophic interactions of the Jumbo squid, Dosidicus gigas, in the California current. In: California Cooperative Oceanic Fisheries Investigations 48. ( Online ; PDF; 2.5 MB)
- ↑ a b R. Rosas-Luis et al .: Importance of jumbo squid Dosidicus gigas (d'Orbigny, 1835) in the pelagic ecosystem of the central Gulf of California. 2008 In: ecological modeling 218, pp. 149–161. ( Online ; PDF; 718 kB)
- ^ Benjamin P. Burford and Bruce H. Robison: Bioluminescent backlighting illuminates the complex visual signals of a social squid in the deep sea. PNAS, March 2020 doi: 10.1073 / pnas.1920875117
- ↑ FAO : Fish, crustaceans, molluscs, etc. Capture production by principal species in 2010. ( Online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove it this notice. )
- ^ Information describing Dosidicus gigas fisheries relating to the South Pacific Regional Fisheries Management Organization. ( Online ( Memento from February 27, 2013 in the Internet Archive ); PDF; 270 kB)
- ↑ P. Jereb, CFE Roper: Cephalopods of the World. FAO, 2006, ISBN 978-9251053836 , p. 9.
- ↑ Nathalie Thanh Thuy Schwertner: Chile: 60,000 dead squids washed up on the beach. In: reisereporter.de. February 14, 2019, accessed February 27, 2019 .
