Sakhalin sturgeon
| Sakhalin sturgeon | ||||||||||||
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A Sakhalin sturgeon on a commemorative ruble coin |
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| Acipenser mikadoi | ||||||||||||
| Hilgendorf , 1892 |
The Sakhalin sturgeon ( Acipenser mikadoi ) is a species of fish from the family of sturgeons (Acipenseridae). It occurs close to the coast in the Bering Sea , the Sea of Okhotsk and the Sea of Japan , on the coast of the Kamchatka Peninsula , on the east coast of the Japanese island of Hokkaido and on the Pacific coasts of Russia and North Korea south to Wonsan .
Systematics
The Sakhalin sturgeon was described in 1892 by the German zoologist Franz Martin Hilgendorf , but later only recognized as an independent species by a few scientists (including Jordan ). Most saw populations of the North American green sturgeon ( Acipenser medirostris ) or a subspecies of the green sturgeon ( A. medirostris mikadoi ) in the Northeast Asian sturgeon stocks . However, exact morphometric examinations and the DNA comparison showed that the green sturgeon and the Sakhalin sturgeon are two different species.
features
The Sakhalin sturgeon reaches a maximum length of 1.30 meters. Its elongated body has five longitudinal rows of hunched bone scales (scuta). It can be distinguished from the green sturgeon mainly by the number of lateral scales (18 to 27 (mean 23) in the Sakhalin sturgeon vs. 25 to 30 (mean 27.9) in the green sturgeon). In addition, the anal fin of the Sakhalin sturgeon is supported by more fin rays than that of the green sturgeon (27 to 36 (mean 31.3) in the Sakhalin sturgeon vs. 25 to 31 (mean 28.9) in the green sturgeon). The barbels of the Sakhalin sturgeon are closer to the mouth than the tip of the snout, of the green sturgeon they are closer to the tip of the snout or the distances from the tip of the snout to barbels and barbels to the mouth are the same length. The Sakhalin sturgeon usually has no more than nine bone scales on the outer abdominal sides between the pair of fins, the green sturgeon usually has more than nine scales there. The number of gill rakes in the Sakhalin sturgeon is less than twenty, and in the green sturgeon it is usually more than twenty. Along the midline of the back, the Sakhalin sturgeon has 7 to 11 bone scales. Genetically, Sakhalin sturgeon and green sturgeon differ mainly in terms of their karyotype .
- Fin formula : dorsal 33–40, anal 22–30.
Way of life
The Sakhalin sturgeon occurs near the coast in the sea, in the salt and brackish water of estuaries and in the fresh water of the river lower reaches. The adult animals migrate up the rivers from April to May and return to the sea in autumn. The only known spawning water of the species was initially the Tumnin River in the Russian region of Khabarovsk . Reproduction takes place there in June and July. The species was later also detected in the Viyakhtu River, Sakhalin .
Danger
The IUCN estimates the population of the Sakhalin sturgeon as critically endangered (threatened with extinction). The reasons are illegal fishing, pollution of the environment and the construction of dams. In the past 45 years, the stock is said to have decreased by 80%.
Individual evidence
- ↑ a b c Acipenser mikadoi in the endangered Red List species the IUCN 2006. Posted by: St. Pierre, R. & Pourkazemi, M. (Sturgeon Red List Authority), 2009. Accessed November 15 of 2010.
- ↑ a b c E. D. Vasiléva, VP Vasilév, SV Shedko and GV Novomodny: The Validation of Specific Status of the Sakhalin Sturgeon Acipenser mikadoi (Acipenseridae) in the Light of Recent Genetic and Morphological Data. Journal of Ichthyology, 2009, Vol. 49, No. 10, pp. 868-873. ISSN 0032-9452
- ↑ a b c Sakhalin sturgeon on Fishbase.org (English)
- ↑ VN Koshelev. V. Mikodina, N. Mironova, AV Presnyakov, AG Novosadov (2012): New data on biology and distribution of Sakhalin sturgeon Acipenser mikadoi. Journal of Ichthyology 52 (9): 619-627. doi : 10.1134 / S0032945212050025