PISCINE ORTHOREOVIRUS (PRV) IN SALMON IN BRITISH COLUMBIA: RISK VS. CONSEQUENCES

Our measured physiological consequences of injecting concentrated, BC-strain PRV into juvenile sockeye and Atlantic salmon were incompatible with  a  previous suggestion of sub-lethal cardio-respiratory impacts. P eak PCR response at 4-6 weeks post-injection and  a sustained  PRV infection,

at or beyond that seen in wild and farmed salmon,

produced no mortality and body condition was maintained. Well-established respirometry techniques for individual fish compared

 time-matched  measurements of routine (RMR), maximum (MMR) and hypoxic respiratory performance  with sham-injected salmon. While blood hemoglobin concentration and hematocrit decreased modestly at week 4 post-infection in sockeye and at weeks 1 and 9 in Atlantic

salmon , these  modest changes were not sustained at week 9 in sockeye or at week 18 in Atlantic salmon .  However, neither RMR ,  MMR nor hypoxia tolerance of PRV-infected  salmon  were significantly different from  their  time-matched controls, except MMR was  significantly higher in infected Atlantic

salmon at week 10.