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
Soft-shell crab main species is the blue crab, "Callinectes sapidus", which appears in markets from April to September. In the Deep South region of the United States, "Buster crab" is often a synonym for a plump, meaty soft-shell crab, this usage especially common in the culinary centers such as New Orleans and Charlotte. This is despite the fact that the original meaning of Buster crab referred to either a soft-shell that had yet to complete molting, or to a soft-shell that had died before being provided to a seafood vendor, and was then consumed by the crabber. In Japan, various species are