Thorny seahorse

from Wikipedia, the free encyclopedia
Thorny seahorse
Hippocampus hystrix (Spiny seahorse) .jpg

Thorny Seahorse ( Hippocampus histrix )

Systematics
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
Order : Pipefish (Syngnathiformes)
Family : Pipefish (Syngnathidae)
Genre : Seahorse ( hippocampus )
Type : Thorny seahorse
Scientific name
Hippocampus histrix
Kaup , 1856

The thorny seahorse ( Hippocampus histrix ) is a species of the seahorse genus . It lives in the western Indo-Pacific and is endangered according to the IUCN .

features

Yellow copy

With a body shape that is typical for seahorses, they have no scales, only skin that lies over their bones. In addition, their entire body is covered by very sharp and long spines, which are colored black at their tips. There are particularly long spines distributed over the trunk to their crown. They reach a maximum body length of 17 centimeters. The bones are arranged in rows around the torso in a ring shape, forming bone plates and thus a skin-bone armor that acts like armor for the animal. They have a total of eleven bone rings.

The thorny seahorse appears in different colors depending on the environment. It can be bright yellow, green, or red. Reddish animals are mainly found at greater depths. Since water mainly absorbs long frequency ranges of light, red light is no longer available from a depth of a few meters and the animals appear gray. They are usually uniformly colored and have small red spots on the neck and back. The snout is often marked by several fine white bars. The long snout is striking in young and sometimes older male specimens. Their tail is used to wrap grasses or fellow species, this anchors the animals and they hold on to avoid being washed away. The tail can only be moved downwards.

  • Yellow and brown specimen

  • Hippocampus histrix (Juvenile thorny seahorse) .jpg
  • Hippocampus histrix, juvenil.jpg

  • The snout in detail

Distribution and habitat

This seahorse is widespread in the Indo-Pacific and is found from Southeast Africa and Madagascar to Japan , Hawaii and French Polynesia . It usually resides at a depth of between 10 and 40 meters, but can also occur deeper - up to a maximum of 82 meters. Sometimes it can also be found in shallower areas, such as between scree lying at a depth of approx. 10 meters and overgrown with algae. It swims over a variety of different bottoms, including rocky reefs, and can be found near sponges , soft corals, or in seagrass beds . Often it also drifts in the current and clings to objects.

Danger

Fishing poses a threat to the thorny seahorse; it is targeted as well as by-catch in the course of shrimp fishing. The latter places a particular burden on the population. Fishermen and traders have been reporting a decline in the number of animals since the mid-1990s. Another problem is the deterioration of the habitat of these seahorses. Due to various factors such as sedimentation, dredging and structures close to the beach, destructive fishing practices such as trawl and dynamite, and climate change, coastal seaweed stocks and corals are destroyed.

The thorny seahorse is one of the six most internationally traded seahorse species. The entire genus Hippocampus was listed in Appendix II of the Washington Convention on the Protection of Species in November 2002 . This means that commercial trade is possible after a safety assessment by the exporting country. The thorny seahorse is traded both live and processed. Living specimens must have a minimum size of 10 centimeters and are usually traded as aquarium fish. Dried and then ground, these fish are traded as remedies and sexual enhancers in traditional Chinese medicine .

The trade is reported from every country this seahorse is native to. Since it was listed in the Washington Convention on the Protection of Species, around 200,000 specimens were traded annually between 2004 and 2010. However, since a large part of the trade reported to the Washington Convention only includes the genus hippocampus , these figures are inaccurate. The exact proportions of the individual species in the reported catch are unclear. In addition, it should be noted that seahorses with similar characteristics are called and traded as hippocampus histrix out of ignorance , although they do not belong to this species. It is likely that the trading volume is underestimated.

As the main threats to the thorny seahorse persist and in some cases are intensifying, it is classified as endangered on the Red List of Endangered Species .

Aquaristics

In principle, the keeping of Hippocampus histrix is notifiable, and it is important to pay attention to the relevant evidence when purchasing. In addition, keeping these seahorses is demanding and should therefore only be considered by experts.

As is usual with seahorses, the thorny seahorse should also be kept in a special seahorse-friendly tank. It should offer the animal many opportunities to hold onto objects or plants with its tail or to clasp them. Options include caulerpa , horn corals , soft corals or fine ceramics. Stinging corals should be avoided because of the stinging poison, the current speed should not be too strong and the pool height should exceed 50 centimeters. The aquarium should hold more than 300 liters and the water temperature should be between 22 and 24 ° C. The thorny seahorse is very demanding in terms of water quality and absolutely needs soft corals, and the pool must not be illuminated too strongly. The seahorse should be fed four to six times a day, preferring live foods such as mysis . Because of the high frequency of feeding, you should pay attention to a powerful skimmer . They should also be kept in pairs or in groups. Group keeping is also possible with other pipefish or mandarin fish. The thorny seahorse is prone to gas bubble disease .

supporting documents

  1. ↑ a b c d e f Hippocampus histrix in the Red List of Threatened Species of the IUCN 2018-1. Posted by: Pollom, R., 2017-01-26.
  2. ↑ a b c d e Hippocampus histrix (Hippocampus histrix). WESO Software GmbH, accessed on September 23, 2018 .
  3. ↑ a b c d Dianne J. Bray: Thorny Seahorse, Hippocampus histrix Kaup 1856. Fishes of Australia, accessed on September 23, 2018 (English).
  4. ↑ Rudie H. Kuiter : Seahorses: pipefish, shredded fish and their relatives. Eugen Ulmer, 2001, ISBN 3-8001-3244-3 . Page 32.
  5. ↑ Hippocampus histrix on Fishbase.org (English)

Web links

Commons : Hippocampus histrix  - collection of images, videos and audio files