In Austria, the bullhead is a potentially endangered fish species. It prefers to live in what are now rare sections of well-structured river rich in oxygen with rapid flow. It is a typical accompanying species in trout and grayling regions.
additional link https://en.wikipedia.org/wiki/European_bullhead
"Inneralpines Flussraummanagement
Obere Mur"
Gemeinsame Wege von Wasserbau und Naturschutz.
Auszeichnung der Flussaufweitung Weyern mit der GerambRose 2010