Viper fish

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Viper fish
Pacific viperfish (Chauliodus macouni)

Pacific viperfish ( Chauliodus macouni )

Systematics
Cohort : Euteleosteomorpha
Sub-cohort : Stomiati
Order : Maulstachler (Stomiiformes)
Family : Whale dragonfish (Stomiidae)
Subfamily : Chauliodontinae
Genre : Viper fish
Scientific name of the  subfamily
Chauliodontinae
Bonaparte , 1846
Scientific name of the  genus
Chauliodus
Bloch & Schneider , 1801

The viper fish ( Chauliodus ) are a genus of the baleen dragon fish ( Stomiidae) and the only genus of the subfamily Chauliodontinae. Since they lack the barbels , some ichthyologists place them in their own family, the Chauliodontidae. According to current knowledge, they are more closely related to the deep-sea hatchet fish (Sternoptychidae) than to the other subfamilies of the bearded dragon fish . Viper fish are predators of the deep sea. They are highly specialized for an existence in this seemingly hostile living space. With a height of around 30 centimeters (maximum 35 cm), they belong to the larger, but also quite common fish of the upper deep sea.

The name Chauliodus means “tusks” (in ancient Greek animals with prominent protruding teeth, “tusks”, were called, for example the hippopotamus).

features

The viper fish have often been described as bizarre, glowing predators of the deep sea . In the upper jaw, the premaxillary (i.e. the intermaxillary bone ) is dentate. The maxillary bears a number of smaller teeth. The fangs of the lower jaw are of different sizes (the two longest are at the front end) and curved backwards. They are astonishingly constant and protrude a long way even when the mouth is closed. Contrary to older information, the dagger-shaped, partly sharp-edged fangs cannot be folded back (Tchernavin 1953) - not like pike , hake , monkfish and Chiasmodon niger - or the vipers of the mainland. Tearing out (the teeth are not in the alveoli ) or breaking out of a tooth during the act of eating is not a major misfortune - replacement teeth are always available in the oral mucosa, as repeated tooth changes are necessary due to the growth. What is unclear, however, is the advantage of this exaggerated “terrible” looking dentition (hyper-, dystelia ?). In any case, the mouth has to be opened wide to grab hold of it - as with many other fish, this is done by throwing the skull in the neck, for which the first vertebra is only loosely connected (without a joint) to the occiput. The silver eyes are relatively large in relation to the head - they then look through the tooth enclosure (it was really thought that this served as a “cage” for prey fish). The eyes of the viper fish outperform the human eye by 30 times when it comes to adapting to weak light.

The body is elongated and covered with luminous organs that look like glands ( Albert von Kölliker 1853). If a living viperfish is touched, its entire body glows in a pulsating light. Some species have up to 1500 composite light organs, which in the past were sometimes even thought to be additional eyes. They are very efficient, about 98% of the supplied energy can in light converted to.

He is shed covered that separate easily from the skin. The dorsal fin , located just behind the head in front of the pelvic fins, has five to seven fin rays , the first of which is greatly elongated. The anal fin is supported by 10 to 13 fin rays. Live viper fish are covered by a thick layer of mucus. They are 14 to 35 centimeters long.

habitat

Viper fish are predators of the deep sea and inhabit the meso- and bathypelagial . In this deep-sea layer they live at depths between 400 and 1800 meters (individual specimens have already been caught from 4400 m depth). Already at 400 m there is hardly any natural light left, except for a small amount of blue light, which in extremely clear water reaches a depth of approx. 875 m.

Importance of the plankton

Fish are rarer in the mesopelagial due to less food than in the lighted epipelagial - plants cannot survive there without light. All of life therefore depends on plankton , as the water in the mesopelagial is very rich in zooplankton. At night, the zooplankton moves upwards in order to eat even smaller organisms, mainly phytoplankton , in the epipelagial region . There are many nutrient-rich microorganisms on the surface of the water. Numerous other small deep-sea animals follow the plankton upwards and feed on it. These animals form a crucial link in the deep sea food web. Every night, the largest regular migration of animals will take place on our planet: the small deep-sea fish, such as the gonostomatidae , lantern fish or sternoptychidae , return to the nutrient-rich plankton in the stomach in deeper regions back. Here, they will be of predators such as the Viper fish ambushed . Some of the viper fish do the vertical migration themselves for a certain distance.

Food and hunting

The viper fish are highly specialized predators , all species are eye hunters, which means that they first perceive the movements of other approaching deep-sea inhabitants with their large eyes. Each eye has a special luminous organ, which is located under the pupil and which significantly improves the fish's ability to perceive light. Other light organs located on the eye are used as a kind of "spotlight" to illuminate the victim before the fish snap shut. A curious peculiarity of these stomiids is also the lack of the floor of the mouth, which makes snapping even easier.

Within the mesopelagial layer, viper fish live in all temperate and tropical oceans. They can also be found in the Mediterranean and sometimes even in the North Sea (an occurrence in the Baltic Sea , however, is unlikely, as it has a maximum depth of 450 meters). The most important species, Chauliodus sloani (named after Hans Sloane ), prefers the more nutrient-rich waters away from the central ocean , i.e. outside the equatorial parts of the Atlantic , Pacific and Indian Oceans furthest from the coast .

behavior

Most of the behavior of the viper fish is largely unexplored. Only the hunting behavior is considered reliable knowledge. It is also certain that viper fish are solitary animals. The slowly swimming predatory fish mostly “lie” in wait for their prey (fish, crustaceans, cephalopods). For this, the viper fish drift almost motionless through the depths for a long time. Their tissues are relatively rich in fat and wax , which supports buoyancy and supports the strong mineralization of the teeth.

Hunting methods

The big eyes of the viper fish search the deep sea for possible prey while the fish is at rest. The large lens and the multi-layered retina enable the viper fish to perceive even small amounts of light. The large jaws of the fish are still closed. Another luminous organ sits on the movable dorsal fin ray. With this "light" that can be moved in front of the mouth, the hunter attracts the attention of other deep-sea dwellers (supposedly also by blinking). To do this, the viper fish use a proven form of adaptation in the deep sea, bioluminescence : they are able to generate light without heat. This requires a chemical reaction in which luciferin is oxidized. The viper fish have special light organs for the generation of light. In addition to the viper fish, many other deep-sea animals have this ability, such as deep-sea angler fish , vampire squid or the black snake . Any prey that is too curious and swims to the light source of a viper fish will be caught by it. The dental stilettos of the lower jaw stab the prey and hold it in place. In order to be able to swallow prey that is almost as big as the fish itself, the viper fish can unhook its lower jaw - in analogy to the eponymous snakes. During this process, however, breathing and blood circulation are hindered as the gills of the viper fish are retracted. If the prey is particularly large, the respiratory organs are exposed. The prey must therefore be swallowed quickly in order to restore the blood and oxygen supply. With the scarce food supply in the deep sea, it is necessary to be able to grab any prey that is present.

Reproduction

The habitat of the viper fish is almost inaccessible to humans. Divers have already been able to observe viper fish from controllable diving vehicles, but many behaviors, such as reproductive behavior, remain hidden. Potential sexual partners rarely come close in the vastness of the deep sea. Outwardly, males and females hardly differ. Researchers assume that the viper fish produce a larger number of eggs, which initially develop into the larval stage . The larvae are most often found in spring. They are very elongated, but should probably not be called " leptocephalus-like ". Viper fish are understandably slow-growing and long-lived - they should take 35 years to reach their maximum length.

Viper fish and human

The viper fish living in the deep sea are of no economic importance to humans. They remain largely withdrawn from human influence. Few people have ever seen a viper fish. Its way of life is almost unexplored in the dark of remote ocean depths.

A viper fish is depicted on a 2 franc postage stamp from the Republic of the Congo . It is Chauliodus sloani .

species

The genus Chauliodus comprises nine species:

Chauliodus sloani

Individual evidence

  1. ↑ Ricardo Betancur-R., Richard E. Broughton, Edward O. Wiley, Kent Carpenter, J. Andrés López, Chenhong Li, Nancy I. Holcroft, Dahiana Arcila, Millicent Sanciangco, James C Cureton II, Feifei Zhang, Thaddaeus Buser, Matthew A. Campbell, Jesus A Ballesteros, Adela Roa-Varon, Stuart Willis, W. Calvin Borden, Thaine Rowley, Paulette C. Reneau, Daniel J. Hough, Guoqing Lu, Terry Grande, Gloria Arratia, Guillermo Ortí: The Tree of Life and a New Classification of Bony Fishes. PLOS Currents Tree of Life. 2013 Apr 18 [last modified: 2013 Apr 23]. Edition 1. doi: 10.1371 / currents.tol.53ba26640df0ccaee75bb165c8c26288 , PDF ( Memento of the original from October 13, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / currents.plos.org
  2. ↑ Fascination Animal and Nature, Group 4 - Fish (No. 33), page 131. See also references.
  3. ↑ Experiencing knowledge in a new way - Oceans (In the deep sea), page 178. See also references.
  4. ↑ Gruner + Jahr AG (Ed.) GEO - Ozean und Tiefsee, Hamburg 2003, pages 94/95. See also references.
  5. ↑ Fascination Animal and Nature, Group 4 - Fish (No. 33), page 132. See also references.
  6. ↑ a b Experience new knowledge - Oceans (In the deep sea), page 184. See also references.
  7. ↑ Fascination Animal and Nature, Group 4 - Fish (No. 33), page 130. See also references.
  8. ↑ Fishbase
  9. ↑ Viper fish on Fishbase.org (English)

literature

  • William C. Beebe: Half mile down. New York, 1934.
  • VV Tchernavin: Summary of the feeding mechanisms of a deep sea fish. Chauliodus sloani. Schneider, British Museum (Natural History), London 1953.
  • K. Günther and K. Deckert: Second attempt at a morphological-anatomical functional analysis of the food acquisition and respiratory systems of deep-sea fish. Zool. Contribution (NF) 1 (1955): 241-365.
  • Detlef Singer: Fascination with animals & nature, group 4 - fish. Munich without a year.
  • Rainer Klingholz u. a .: GEO - ocean and deep sea. Gruhner + Jahr AG (ed.), Hamburg 2003.
  • Kurt Fiedler: Textbook of Special Zoology, Volume II, Part 2: Fish. Gustav Fischer Verlag Jena, 1991, ISBN 3-334-00339-6 .
  • Joseph S. Nelson: Fishes of the World. John Wiley & Sons, 2006, ISBN 0-471-25031-7 .
  • Stephen Hutchinson, Lawrence Hawkins: Re-experiencing Knowledge - Oceans (In the Deep Sea). blv-Verlag, Munich 2004, ISBN 3-405-16817-1 .

Web links

Commons : Chauliodus  - collection of images, videos and audio files