Elegant paradise threadfish
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Elegant Paradise Threadfish ( Polynemus multifilis ) |
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| Polynemus multifilis | ||||||||||||
| Temminck & Schlegel , 1843 |
The Elegant Paradise gourami ( Polynemus multifilis ) is a threadfin , which in some rivers of Southeast Asia occurs. It can be distinguished from other species of the genus Polynemus by 13 to 14 thread-like free pectoral fin rays, of which the penultimate pair can reach up to four times the body length .
features
The peculiarity of the Polynemidae family (thread flossers, called "threaders" in Brehm's animal life ) is that a nerve branch belonging to the facial nerve (nervus facialis, responsible for the sensation of taste), the Weberi nerve, named after its discoverer (1817), which belongs to Fish can also otherwise be distributed on the trunk skin and fins, in this family the pectoral fins partly become organs of taste (cf. pelvic fins of the Osphronemidae , some of which are also called “ thread fish ”, dorsal fin in Gaidropsarus from the Gadidae family ). On the other hand, the lower pectoral fin rays of the Triglidae , which serve as "fingers" for walking around and palpating, are not so adapted. In Polynemus multifilis , the majority of the pectoral fin rays are affected.
Fins formula : D1 VIII, D2 I / 14-16, A III / 11-13, P 9 and 13-14 free rays (the penultimate one is usually the longest - up to four times the body length; the lower ones are much shorter). VI / 5, C 22-23. - 25 vertebrae, 15 of which are caudal. 83-99 (mostly 86) sideline scales. The tail fin is large - it has to overcome the water resistance of the thread train. The body is flattened on the sides. The free edge of the gill cover is slightly serrated. The color is simply silvery, the maximum size is 28 cm.
Polynemus multifilis differs from the related Polynemus kapuasensis , described in 2003 by Motomura and van Oijen from the Kapuas River system in the province of Kalimantan Barat on Borneo, as the latter has 15 or 16 free pectoral fin rays. All other Polynemus species have only 7 free pectoral fin rays.
distribution
This fish lives in the mouth of the Mae Nam Chao Phraya (Thailand) and other rivers in the vicinity, in which it also rises - it is predominantly freshwater inhabitant, but also lives in brackish water. Where it reproduces is unclear. Probably its spawning areas are in the pelagic part of the sea. As it is also known from widely spaced river systems in Sumatra and South Borneo , its range is possibly much larger than is documented today.
behavior
The fish swims slowly over the bottom in the murky water and, with its dragging, hair-like, long-drawn taste rays, which it can throw far forward beforehand, detects organisms in the sediment (sand to mud), which it then snaps open with its lower mouth . It would be even “better” if the “antennae” were further forward - for example on the lower jaw (such as in the perhaps related Mullidae and the Sciaenidae ) or at least in front of the hyoid (as in the more primitive Polymixiidae ).
Polynemus multifilis feeds on small fish, crustaceans and other benthic organisms.
use
Polynemus multifilis , like the other threadlocks, is of considerable importance for the fishing industry on the rivers in which it occurs. However, detailed catch statistics for individual species are not kept by local fishermen and therefore the figure of 93,000 tonnes reported by the FAO in 2001 for all species of Polynemidae combined is likely to be greatly underestimated.
Because of its peculiar appearance and the "elegant" movements of the trolling, the Elegant Paradise Threadfish is not only eaten after it has been caught in a net, but also exported as a decorative fish, especially to Japan.
Remarks
- ↑ The German or English language name actually refers to a related species, P. paradiseus - whereby the name is mostly rendered as "elegant paradiseus threadfish" due to an "automatically" (electronically) increased carelessness in English.
literature
- H. Motomura: Threadfins of the world (Family Polynemidae). An annotated and illustrated catalog of polynemid species known to date. FAO Species Catalog for Fishery Purposes, No. 3, FAO, Rome 2004, page 91 online
Web links
- Elegant Paradise Threadfish on Fishbase.org (English)
- Elegant paradise threadfish on Aquanet (photo)