Monitoring of the in‐river migration of smolts from two groups of spring chinook salmon,Oncorhynchus tshawytscha(Walbaum), with different profiles ofRenibacterium salmoninaruminfection

摘要

AbstractBroodstock segregation based on the measurement of maternalRenibacterium salmoninaruminfection levels by the enzyme‐linked immunosorbent assay (ELISA) and the membrane filtration‐fluorescent antibody technique (MF‐FAT) was previously shown to affect the prevalence and levels of bacterial kidney disease (BKD) in progeny of chinook salmon,Oncorhynchus tshawytscha(Walbaum), during hatchery rearing. Subgroups of fish from that study were marked with passive integrated transponder (PIT) tags, and monitored by PIT‐tag detectors during the first 342km of their migration to the Pacific Ocean. Differences in the recovery of tagged fish were significant (P≤ 0·01) at each detection point and became more pronounced as the fish moved downstream. Cumulative recoveries of fish from the low‐BKD group and the high‐BKD group, respectively, were 31 and 28 after 116km, 44 and 37 after 176km, and 51 and 42 after 342km. There were no apparent differences in the migration timing of the two groups to the first detection point. The data suggested that in‐river survival was higher in the progeny group from parents that had lowR. salmoninaruminfection levels or tested negative forR. salmoninarum(low‐BKD group) than in the group female parents with high infection level