photobacteriosis (ex Pasteurellosis) Aetiological agent/s Photobacterium damselae subspecies piscicida Epidemiology Host/s (species; age): All Mediterranean farmed fish: seabream (Sparus auratus) as well as all other sparids, seabass (Dicentrarchus labrax), meagre (Argyrosomus regius). The younger the fish the more sensitive they are. Morbidity and mortality rates: Depend on age/size class. Juveniles up to 80%, fry up to 60%, on growers up to 40% when fish are not immunized and are left untreated. Transmission: Horizontal as well as vertical (via infected eggs). Factors (environmental, others) for disease outbreak: The disease is temperature-dependent. Outbreaks often occur at seawater temperatures between 18-26oC. Site and cage excessive stocking densities predispose horizontal transmission.