Caspian shad
Caspian shad ( Alosa caspia )
The Caspian shad ( Alosa caspia ) is a migratory fish of the Black Sea, the Sea of Azov, the Caspian Sea and is found in the leading- rivers. He belongs to the herring -like ( Clupeiformes ).
Features
He has the typical laterally flattened, somewhat hochrückigere shape of the freshwater herring and is up to 32 cm long, but usually remains at a length of 20 cm. The body height can reach ¼ of the total length. The body is covered by relatively large roundhouse. The upper jaw is notched in the middle, the lower jaw extends to the posterior margin. The vomer is dentate. The maxillary teeth are poorly developed and sometimes hardly noticeable. The number of gill Reuse rays is from 50 to 180 They are significantly longer than the Kiemenfilamente and thin.
The Caspian shad is on the back side greenish to bluish and silvery on the sides of the body and belly. One to eight large black spots show up behind the gill cover along the edges.
Way of life
The Caspian shad lives in flocks and is an anadromous migratory fish. In the sea he lives in coastal pelagic, well- perfused areas and avoids regions with consistently high salinity. For reproduction, he wanders into the rivers and spawns in freshwater or slightly brackish water above three meters deep. Some of the species spawn in the sea in brackish or salt water. North of the Caspian Sea does the reproductive period from April to June. Males begin breeding activities at age 2-3 years, females with 4 to 5 years. Many spawn per season 2 to 4 times. The Caspian shad 's needs warmth. The spawning migration starts when the water temperature is above 10 ° C, spawned at a temperature of 15 ° C.
In the sea, the Caspian shad feeds mainly on zooplankton ( copepods and Mysiden ).
Subspecies
- Alosa caspia caspia ( Eichwald, 1838)
- Alosa caspia Bulgarica Drensky, 1934
- Alosa caspia knipowitschi ( Ilyin, 1927)
- Alosa caspia persica ( Ilyin, 1927)
- Alosa caspia salina ( Svetovidov, 1936)