Alosa kessleri Alosa kessleri Alosa kessleri, also referred to as the Caspian anadromous shad, the blackback, or the black-spined herring, is a species of clupeid fish. It is one of the several species of shad endemic to the Caspian Sea basin. This is an anadromous species which ascends from the Caspian to the Volga river up to the Volgograd to spawn. Before the construction of th Volgograd dam it migrated up to the Kama and Oka tributaries. Few fish enter the Terek and Ural Rivers. While the migration upstream is broken, it seems the fish have found new breeding grounds south of
Alosa Most individuals die shortly after spawning. "Alosa" species are seemingly very adaptive vertebrates, so can change readily to adapt to their environments, as species are found in a variety of temperatures and waters. As "Alosa" species are generally anadromous, they are faced with various obstacles to survival. They may have to pass through numerous barriers and waters to get to either their spawning grounds or normal habitats (the sea in most cases). Estuaries are a major factor in numerous "Alosa" species' migration. Estuaries can be highly variable and complex environments contributing to fluctuating biological interactions, with shifts in osomolarity, food