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
Herring as food in Europe, and early in the twentieth century their study was fundamental to evolution of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled. Herring are very high in the long-chain Omega-3 fatty acids EPA and DHA. They are a source of vitamin D. Water pollution influences the amount of herring that may be safely consumed. For example, large Baltic herring slightly exceeds recommended limits with respect to PCB and dioxin, although some sources point out that cancer-reducing effect of omega-3 fatty acids is statistically stronger than