Caribbean reef squid

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Caribbean reef squid
Caribbean reef squid on a reef near Bonaire

Caribbean reef squid on a reef near Bonaire

Systematics
Class : Cephalopods (cephalopoda)
Subclass : Octopus (coleoidea)
Order : Squids (Teuthida)
Family : Closing eyes squid (Loliginidae)
Genre : Sepioteuthis
Type : Caribbean reef squid
Scientific name
Sepioteuthis sepioidea
( Blainville , 1823)

The Caribbean reef squid ( Sepioteuthis sepioidea ) is a squid in the family of closed eyes squid (Loliginidae).

Morphology and motor skills

Head profile

The maximum body length is 20 cm. The body consists of a torso in which the internal organs are enclosed by a muscular skin sac. This skin sac is called the coat . The head has ten tentacles, two long and eight short, whereby the long tentacles can be retracted into the wreath of tentacles. An outer shell is missing, the chitinous gladius is in the mantle area on the back . This thus represents an inner shell, which gives the squid's body stability. The muscles are also anchored to the gladius. At the front end of the mantle, below the head, there is a tubular opening called the mantle funnel. It supplies the two gills in the mantle cavity with fresh, oxygen-rich water, but also serves for rapid locomotion by means of recoil. The eyes of the Caribbean reef squid have very good eyesight. The pharynx is provided with a parrot-like beak, with the mollusc-typical rasp tongue (radula) in between. The species has a characteristic fin on both sides of the body, along the entire length of the mantle in adults, the widest point of which is roughly in the middle of the mantle. This enables the animals to swim forward by means of wave movements. However, this allows only very slow progress. The Caribbean reef squid normally suck water through the mantle funnel into the mantle cavity and then press it out again under pressure through the funnel. Thus, the body is moved backwards by means of a recoil principle. This principle of locomotion enables high speeds.

distribution and habitat

Main distribution area of ​​the Caribbean reef squid

The Caribbean reef squid is the only species of the genus Sepioteuthis that occurs in the Atlantic and is mainly native to the Gulf of Mexico and the Caribbean . The Caribbean reef squid occurs at depths of around 1.5 m to 100 m. The normal depth range in adult animals is between 1.5 m and 8 m. Young animals usually live at depths of around 2 m and stay near seagrass meadows . It is a species that occurs primarily near the coast. The Caribbean reef squids only occasionally swim in the open sea.

behavior

The Caribbean reef squid often swims in groups

During the day the species is usually found in flocks of 4 to 30 animals. It seldom socializes with the slender coastal squid ( Loligo plei ) or with young pigfish ( Haemulon spp.), Or the threadfin fish ( Polydactylus spp.) In mixed schools. The formation of swarms reduces the risk of becoming prey for the individual. When in danger, he does not rely solely on the protection of a swarm, but also uses his ability to change colors. In stressful situations, the animal turns dark red or brown and hides between corals. In open water, he tries to put distance between himself and the danger with a powerful backward push. As a further defensive measure - like all squids - he has a bag with a dark liquid at his disposal, which he ejects in case of danger. In connection with the jerky recoil, a potential attacker is thus irritated. The Caribbean reef squid is very curious and not shy of people.

Reproduction

When it reaches sexual maturity, the species reproduces once. After reproduction, the animals die. When the time for reproduction has come, the individuals break away from their swarm and form small troops made up of a female ready to mate and two to five males willing to mate. The males try to win over the females with a variety of color and pattern changes. Once a female has decided on a partner, they show complex wedding rituals for hours. Finally, the female signals with a "saddle-shaped" pattern on her back that she is ready for semen delivery. The male uses a modified tentacle to guide the sperm packet (spermatophore) into the female's mantle cavity. The seed packet is now stored in the receptacle, a seed bag provided for this purpose. After mating, the female starts looking for a suitable place to lay the eggs. These are usually rock overhangs, caves, branches of a coral or the empty shells of the great fencing snail ( Strombus gigas ). The eggs are about 8 millimeters long. The female dies a short time after oviposition. Small, fully developed squids hatch from the eggs within a few days. The species does not go through a larval stage. Only the proportions are different from the adult animals. When they are around 10 days old, the young form swarms near the coast.

Life expectancy and exposure

Sepioteuthis sepioidea has a very short life expectancy. It is around 5 months. The Caribbean reef squid are a common and widespread species whose survival is currently not classified as endangered. In contrast to other squids, especially those that migrate in immense schools through the southern oceans, they are not commercially fished anywhere. In the longer term, however, the loss of their coral reef habitats due to human influences, in particular the various pollutants that are dissolved in the sea, the global increase in water temperatures and an increase in UV radiation, could pose a risk. In fact, the number of living coral gardens in the Caribbean has dwindled alarmingly over the past few decades. This undoubtedly has a negative impact on the Caribbean reef squid population.

Synonyms

  • Loligo sepioidea Blainville , 1823

literature

  • Kir Nazimovich Nesis: Cephalopods of the World - squids, cuttlefishes, octopuses, and allies. TFH Publ, Neptune City, NJ, 1987, ISBN 0-86622-051-8 .
  • Mark Norman: Cephalopods A World Guide. ConchBooks, Hackenheim 2000, ISBN 3-925919-32-5 .

Individual evidence

  1. a b Luciana Borrelli, Francesca Gherardi, Graziano Fiorito: A Catalog of Body Patterning in Cephalopoda. Firenze University Press, 2004, ISBN 978-8884533777 , p. 48.
  2. a b c http://www.markuskappeler.ch/tex/texs2/riffkalmar.html
  3. Sepioteuthis sepioidea at World Register of Marine Species (WoRMS)
  4. Sepioteuthis sepioidea at Animal Diversity Web (ADW)

Web links

Commons : Caribbean Reef Squid ( Sepioteuthis sepioidea )  - Collection of images, videos and audio files