| mass mortality of cultured ascidians halocynthia roretzi associated with softening of the tunic and flagellate-like cells. | since 2007, mass mortalities of cultured ascidians halocynthia roretzi (drasche) have occurred in miyagi prefecture, japan. the mortalities occur from november through august, and the tunics of affected animals become abnormally weak and soft. the number of farming areas where mass mortalities have occurred has increased rapidly: 3 in 2007, 6 in 2008, and 14 in 2009. when an outbreak of the disease occurred, mortality reached 17 to 100%. prominent histopathological changes in the diseased ascidi ... | 2010 | 20815331 |