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 auditory meatus, while dark or light speckling or streaking can occur along the flanks as well as what are called "tiger stripes" – "parallel, dark, usually vertical stripes". Like Bryde's whale (and occasionally blue and fin whales), dwarf minkes can exhibit auxiliary ridges on either side of the central ridge of the rostrum. Common minke whales have a disjointed distribution. In the North Atlantic, they occur as far north as Baffin Bay, Svalbard, Franz Josef Land, and Novaya Zemlya and as far south as 40°N (New Jersey) and the Hebrides and central North Sea during summer. There are a few