Danube bleak by the building of dams across many of the rivers. Landlocked populations survive in small rivers and reservoirs, breeding in the small streams above the dams. The main Caspian Sea population has found ways of spawning below the dams. Overfishing and pollution in the Caspian Sea could impact on the Danube bleak but in 2008 the IUCN Red List of Threatened Species listed it as being of "Least concern". The Danube bleak feeds on small crustaceans, worms, molluscs, insect larvae, insects and small fish. Male Danube bleaks assemble in May to July at spawning sites in fast flowing streams with
Omura's whale Omura's whale Omura's whale or the dwarf fin whale ("Balaenoptera omurai") is a species of rorqual about which very little is known. Before its formal description, it was referred to as a small, "dwarf" or "pygmy" form of Bryde's whale by various sources. The common name and specific epithet commemorate Japanese cetologist . The scientific description of this whale was made in "Nature" in 2003 by three Japanese scientists. They determined the existence of the species by analysing the morphology and mitochondrial DNA of nine individuals – eight caught by Japanese research vessels in the late 1970s in the Indo-Pacific