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
Fish fossil fish but also living gars and bichirs), cycloid, and ctenoid (these last two are found on most bony fish). There are even fish that live mostly on land or lay their eggs on land near water. Mudskippers feed and interact with one another on mudflats and go underwater to hide in their burrows. A single, undescribed species of "Phreatobius", has been called a true "land fish" as this worm-like catfish strictly lives among waterlogged leaf litter. Many species live in underground lakes, underground rivers or aquifers and are popularly known as cavefish. Fish range in size from the huge