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 to dwell in deeper waters. Predators of herring include seabirds, marine mammals such as dolphins, porpoises, whales, seals, and sea lions, predatory fish such as sharks, billfish, tuna, salmon, striped bass, cod, and halibut. Fishermen also catch and eat herring. The predators often cooperate in groups, using different techniques to panic or herd a school of herring into a tight bait ball. Different predators species then use different techniques to pick the fish off in the bait ball. The sailfish raises its sail to make it appear much larger. Swordfish charge at high speed through the bait balls, slashing with