Robuta

https://digitalcommons.unl.edu/usfwspubs/150/ "SALMONID WHIRLING DISEASE" by Ken Wolf and Maria E. Markiw Salmonid whirling disease-sometimes referred to as "blacktail" -is a chronic, noncontagious parasitic infection of trout and, to a lesser extent, other members... whirling diseasekenwolfmaria