| Abstrakt: |
AbstractResource managers considering restoration and reconnection of watersheds to protect and enhance threatened populations of bull trout Salvelinus confluentushave little information about the consequences of bacterial kidney disease (BKD) caused by Renibacterium salmoninarum.To better understand the response of bull trout to R. salmoninarumchallenge, we conducted several laboratory experiments at two water temperatures. The extent, severity, and lethality of BKD in bull trout were compared with those of similarly challenged lake trout S. namaycush, Arctic char S. alpinus, Chinook salmon Oncorhynchus tshawytscha, and rainbow trout O. mykiss. The lethal dose of bacterial cells necessary to induce 50% mortality (LD50) was 10-fold lower at the 15°C challenge than at the 9°C challenge. Of the species tested, bull trout were relatively resistant to BKD, Arctic char were the most susceptible among Salvelinusspecies, and Chinook salmon were the most susceptible among Oncorhynchusspecies tested. Mean time to death was more rapid for all fish tested at 15°C than for fish challenged at 9°C. These results suggest that infection of bull trout with BKD likely poses a low risk to successful restoration of threatened populations. |
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