Can bivalves act as vectors of fish pathogenic bacteria and viruses?

The growth of the Norwegian aquaculture industry inevitably results in a competion for space. Production of both fish and bivalves at one site, or at sites close to each other, has been suggested as a method to increase efficiency of bivalve farming, and utilization of space, as well as to increase the efficency of use of manpower and equipment. However, one potentially disadvantageous side of polyculture is the spreading of diseased. Due to the high value of the salmon industry, and experiences with tran sferable diseases, in particular Infectious Salmon Aamia (ISA), Norway have so far adapted a restrictive practice for allowing any movement of biological material between aquaculture sites. This project aims at investigating risk for transfer of fish (par ticularly salmon) diseases via shellfisk, and via seawater. In addition to ISA virus, Nodavirus and Aeromonas salmonicida subsp. salmoicida have been chosen as models, due to their existant or potential importance in salmon farming, a nd the preexistence of suitable models for challenge and detection. Transmission of fish pathogens via bivalves will be studied in laboratory challenge experiments. In addition, a mathematical model for the spread of infectious agents between fish and bivalve farms will be designed