High infection by Zeuxapta seriolae (Monogenea: Heteraxinidae) associated with mass mortalities of amberjack Seriola dumerili Risso reared in sea cages in the Balearic Islands (Western Mediterranean)

Mass mortalities in the amberjack (Seriola dumerili) cultured in cages in the Balearic Islands are reported in association with high levels of infection Zeuxapta seriolae of the gills. Lamellar lesions caused by the parasite and mechanical blockage of water flow and gas exchange by the entangled mass of flukes, eggs, and polar filaments were likely the cause of severe respiratory disturbances leading to fish death.