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
Atlantic herring not considered to be an Arctic species. The small-sized herring in the inner parts of the Baltic Sea, which is also less fatty than the true Atlantic herring, is considered a distinct subspecies ("Clupea harengus membras") ("Baltic herring"), despite the lack of a distinctive genome. The Baltic herring has a specific name in many local languages (Swedish "strömming", Finnish "silakka", Estonian "räim", "silk", Livonian "siļk", Russian "салака", Polish "śledź bałtycki, sałaka", Latvian "reņģes", Lithuanian "strimelė") and is popularly and in cuisine considered distinct from herring. For example, the Swedish dish surströmming is made from Baltic herring. Herrings reach sexual maturity