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무지개송어와 산천어에 있어서 백점충의 자연 감염 및 수온별, 어종 유래별 인위 감염에 의한 폐사율을 비교하였다. 백점병은 수온이 낮은 시기에는 산천어가 무지개송어에 비해 잘 감염되었으나, 수온이 높은 시기에는 두 어종간의 차이가 없었다. 백점충의 밀도가 높았던 5월을 제외하고는 양어지의 사육수, 찌꺼기에서 백점충이 검출이 되지 않았다. 수온 10℃에서는 무지개송어에 비해 산천어가 백점충에 대한 감수성이 높았으나, 수온 17℃에서는 폐사에 있어 별 차이가 없었다. 이상의 결과로 무지개송어보다 산천어가 저수온에서 백점충에 대한 감수성이 높음을 알 수 있었다.


This study was performed to natural infection of Ichthyophthirius multifiliis and mortalities of two fish species were compared at 10℃ and 17℃ after artificial infection with the parasite. Subsequently compared to motality by the artificial infection with the different parasite orgin of host at 17℃ using rainbow trout Oncorhynchus mykiss. The prevalence of Ichthyophthirius multifiliis in cherry salmon was higher than that in rainbow trout during the periods of low temperature but no difference in high temperature season. The parasite was not detectable in culturing water and detritus except May that of density has been high. Susceptibility to the parasite was higher in cherry salmon than in rainbow trout at 10℃ of water temperature but no difference between two fish species at 17℃. When rainbow trout were infected with Ichthyophthirius multifiliis from rainbow trout and cherry salmon at 17℃, there was no difference in death of host. These results suggest that cherry salmon have higher susceptibility to Ichthyophthirius multifiliis than rainbow trout at low temperature.