Population and Genetic Variation in Resistance of Chinook Salmon to Vibriosis, Furunculosis, and Bacterial Kidney Disease

We examined genetic variation in mortality and mean times to death for three British Columbia populations of chinook salmon Oncorhynchus tshawytscha, subgroups of which were challenged with one of three pathogens: Vibrio anguillarum, which causes vibriosis; Aeromonas salmonicida, which causes furunculosis; or Renibacterium salmoninarum, which causes bacterial kidney disease. In each population, 10 males were mated to 20 females in a nested breeding design, the progeny were divided into groups, and each group was challenged with a pathogen. Heritability estimates (sire component, binary character) of mortality rate were 0.00 for vibriosis, 0.00–0.34 for furunculosis, and 0.00–0.38 for bacterial kidney disease. Estimates of heritabilty for time to death were 0.00 for vibriosis, 0.00–0.02 for furunculosis, and 0.06–0.50 for bacterial kidney disease. There was little correlation among mortality rates for the different pathogens for the families examined in each population. Kitimat River chinook salmon had the lowest mortality rates of the three populations for all pathogens examined; this result indicates that the Kitimat population may possess a nonspecific immune system superior to that of the other populations examined.