Danube an important industry. The Upper Danube ecoregion alone has about 60 fish species and the Lower Danube–Dniester ecoregion has about twice as many. Among these are an exceptionally high diversity of sturgeon, a total of six species (beluga, Russian sturgeon, bastard sturgeon, sterlet, starry sturgeon and European sea sturgeon), but these are all threatened and have largely–or entirely in the case of the European sea sturgeon–disappeared from the river. The huchen, one of the largest species of salmon, is endemic to the Danube basin, but has been introduced elsewhere by humans. Important tourist and natural spots along the Danube include
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