Pontic shad Pontic shad The Pontic shad ("Alosa immaculata", previously "Alosa pontica"), also referred to as the Black Sea shad or Kerch shad, is a species of clupeid fish in the genus "Alosa", native to the Black Sea and Sea of Azov basins. "Alosa immaculata" lives in the Black Sea and Sea of Azov, and adults migrate up rivers to spawn. It may also be found in the Marmara Sea in Turkey. It currently migrates up and spawns in six rivers: the Danube, Dnieper, Dniester, Southern Bug, Don and Kuban Rivers. Previously the migrations reached far upstream, up to 1,600 in Danube
Subterranean river many cities there are natural streams which have been partially or entirely built over. Such man-made examples of subterranean urban streams are too numerous to list, but notable examples include: Some fish (popularly known as cavefish) and other troglobite organisms are adapted to life in subterranean rivers and lakes. Greek mythology included the Styx, Phlegethon, Acheron, Cocytus, and Lethe as rivers within the Underworld. Dante Alighieri, in his "Inferno", included the Acheron, Phlegethon, and Styx as rivers within his subterranean Hell. The river Alph, running "Through caverns measureless to man / Down to a sunless sea" is central to the