Description and characteristics
The Caspian shad (Alosa caspio) is a medium-sized clupeid with a laterally compressed body, silvery scales and a grey-blue back. It has the serrated scutes on the ventral part characteristic of clupeids.
Habitat and distribution
It is an anadromous species that lives in brackish and salt waters, but ascends in spring into the fresh waters of the Danube and the Delta to spawn.
Diet and behaviour
It feeds on small fish, crustaceans and plankton, being an active pelagic species. It forms schools and undertakes seasonal migrations.
Reproduction
Spawning occurs in spring in fresh water at 12–18°C, with females laying pelagic eggs. After spawning, adults return to salt water.
Economic and ecological importance
It has economic value, being caught during migrations. Ecologically, it is an indicator of connectivity between fresh and salt waters.
Threats and conservation
It is affected by dams that block migration and by intensive fishing. Protection of migration routes is essential.
Fishing and legal minimum size
It is caught during the ascent up the Danube. In the table of minimum legal sizes, the Caspian shad (Alosa caspio) has a minimum legal size of 15 cm.
Conclusion
The Caspian shad is a migratory clupeid, important for fishing and ecological connectivity in the Danube Delta.