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
Common minke whale this mistake during Foyn's whaling operations in the Varanger Fjord between 1868 and 1885." It has formerly been known as the little piked whale, the lesser or least rorqual, and the sharp-headed finner. American whalemen in the 19th century simply thought of them as "young finbacks" or a "Finback's calf", apparently under the impression that they were juveniles of their larger relative, the fin whale. They were also called zwergwal (German: "dwarf whale") or vågehval (Norwegian: "bay whale"). In Japan they are called koiwashi-kujira ("little sardine whale") or minku-kujira ("minke whale"). In Greenland they are known by the Danish name