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 and George Heinsohn (1987), though a white-flippered form in the Southern Hemisphere had been noted earlier. The former described a "diminutive form" based on specimens caught off Durban, South Africa, while the latter named a "dwarf form" based on specimens and sightings from Australia. This unnamed subspecies has a prominent white flipper and shoulder blaze and a dark throat patch, whereas what was called the "dark-shouldered" or "ordinary" form of minke whale (now known as a separate species, the Antarctic minke whale, "B. bonaerensis") lacked these contrasting markings. Until recently, all minke whales were considered a single species. However, the