摘要 : The Kitasoo/Xai'xais First Nation established a program to monitor sea lice levels on seaward migrating wild juvenile salmon in their traditional territory which contains the most northerly salmon farming region of British Columbi... 展开 The Kitasoo/Xai'xais First Nation established a program to monitor sea lice levels on seaward migrating wild juvenile salmon in their traditional territory which contains the most northerly salmon farming region of British Columbia. A total of 12 locations were routinely sampled during the period between 2005 and 2008 to gain a better understanding of the levels and patterns of sea lice infestation on wild salmonids in the region. Over 5000 juvenile salmon were collected and examined for sea lice. Around 78% were identified as pink salmon, 18% were chum salmon and the remainder classified as 'other' salmon (coho and sockeye salmon). Two species of sea lice were observed: <i>Lepeophtheirus salmonis</i> and <i>Caligus clemensi</i>. Over 91% of all the juvenile salmon examined had no sea lice and there was no significant difference in <i>L. salmonis</i> prevalence levels among salmon species. However, chum salmon had significantly lower <i>C. clemensi</i> prevalence levels than either pink or 'other' salmon. There were significant annual and regional differences in <i>L. salmonis</i> prevalence on juvenile pink salmon; the lowest prevalence in all sampling zones occurring in 2008, while channels containing salmon farms consistently had higher levels than those without salmon farms. Mean prevalence of <i>L. salmonis</i> in the channels with salmon farms ranged from 2% to 9% which is lower than levels published for the same region in different years or for other areas without salmon farms. <i>C. clemensi</i> prevalence on wild pink salmon was associated with sampling zone and the size of pink salmon; larger juvenile fish were more likely to be infected than smaller fish. During the period of wild juvenile salmon migration, the mean abundance of motile stages of <i>L. salmonis</i> on farmed salmon ranged from 0.13 to 0.79 lice per fish but there were no significant differences among years. In comparison, <i>C. clemensi</i> abundance levels on farms were significantly higher in 2005. Factors contributing to variations in these observations are discussed.Digital Object Identifier http://dx.doi.org/10.1016/j.aquaculture.2011.07.018 收起