Gold dot surgeonfish
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Gold spotted surgeonfish ( Acanthurus nigrofuscus ) |
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| Acanthurus nigrofuscus | ||||||||||||
| ( Forsskål , 1775) |
The Acanthurus Nigrofuscus ( Acanthurus nigrofuscus ), and Brown surgeonfish called, is a kind from the family of surgeonfish .
Appearance
The gold spotted doctor fish has a longitudinally oval, laterally flattened body that is brown to olive in color. In the region of the head, which makes up about 15% of the body, it has noticeable golden points. The German species name can be traced back to this. The dorsal and anal fin, which are lined with blue, can be set up in an imposing manner. The caudal fin is drawn out like a sickle. The body length is about 20 cm. As with all surgeon fish species, the mouth is terminal and has movable bristle teeth. This is an adaptation to the main food algae, which he scrapes off the hard substrate.
In fish ready to spawn, the body color changes. The brown to olive-colored body turns light brown, the fins take on a reddish color and a yellowish stripe on the back appears.
distribution
The gold spotted surgeonfish is widespread in the Red Sea and in the tropical Indo-Pacific as far as Hawaii and the coasts of Japan and the Great Barrier Reef , where it colonizes lagoons and outer reefs. It can be observed up to a depth of 25 meters.
nutrition
It eats thread and leaf algae from hard substrate and prefers red and brown algae in summer and green algae in winter. The eating habits of this fish species have been particularly well researched.
"A. nicrofuscus collects fat reserves on the short days of the winter months and significantly improves its condition, although the species could eat much longer per day in the other seasons. The reserves are stored as lipids in two special fatty tissues , the mesenteries around the sex organs and paired triangular fat pockets above the anal fin. The stored fats have higher levels of triacylglycerol than z. B. Liver and muscle fats, which are used as energy stores in other fish species. It was found that A. nigrofuscus eats much more fleshy green algae ... in winter than in summer ... because at this time the growth phase of the respective algae begins and much less disturbing ride-on algae, bryozoa , detritus and dioatoms with their special flavors sit on the seaweed sprouts. In the summer the doctors have to resort to the inferior red and brown algae. The changes in certain fatty acid contents in the doctor fish fats as a result of eating green algae made people aware of this previously neglected nutritional relationship. Since A. nigrofuscus consumes the reserves eaten up in winter during the gonad formation in spring, this special nutritional relationship is responsible for a successful spawning phase in summer. "
behavior
The diurnal gold spotted surgeonfish is one of the surgeonfish species that are often observed in schools. Shoals of 250 to 400 individuals have been counted on reef sections of 800 meters in length. The reef section is divided into a zone in which the fish stay during their feeding phases and one that they use as a resting zone during the night.
particularities
Like many of the algae-only species of doctor fish, it has symbiotic microorganisms in its digestive tract that enable it to digest its food. In 1985, the Israeli scientist Lev Fishelson of Tel Aviv University discovered the bacterium Epulopiscium fishelsoni , which is one of the largest known bacteria with a length of up to 0.7 millimeters in the bowels of the gold- spotted surgeonfish .
literature
- André Luty: Doctor fish - way of life - care - species. Dähne Verlag, Ettlingen 1999, ISBN 3-921684-61-7 .
- Andreas Vilcinskas: Marine animals of the tropics. Franckh-Kosmos Verlag, Stuttgart 2000, ISBN 3-440-07943-0 .
Web links
- Acanthurus Nigrofuscus on Fishbase.org (English)
- Acanthurus nigrofuscus inthe IUCN 2013 Red List of Threatened Species . Posted by: Choat, JH, McIlwain, J., Abesamis, R., Clements, KD, Myers, R., Nanola, C., Rocha, LA, Russell, B. & Stockwell, B., 2010 . February 2014.