ABSTRACT: Salmon lice Lepeophtheirus salmonis infestation of sea trout Salmo trutta results in both additional marine mortality and behavioral changes which may contribute to sea trout population decline. For effective management of activities that increase exposure to salmon lice, such as salmon aquaculture, it is necessary to have a full understanding of how salmon lice may affect sea trout populations. An individual-based model (IBTRUTTA) was therefore developed to investigate the potential effects of salmon lice infestation on sea trout population abundance and dynamics based on data from the River Halselva and Altafjord system in northern Norway. This model allowed investigation of the effect of lice-induced mortality and also the compensatory salmonid behavioral mechanisms of premature return to freshwater, either persistent for overwintering or transitory after which sea trout could go back to sea. It was found that, in the absence of compensatory mechanisms, even low rates of lice infestation could lead to marked declines in sea trout abundance. Compensatory behavioral mechanisms had the potential to reduce these declines, but persistent premature return resulted in reduced body mass of returning adults. The shape of the stock-recruitment relationship was also shown to strongly affect how lice-induced mortality impacted the population.

中文翻译：

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使用基于个体的方法模拟鲑鱼虱对海鳟种群动态的影响

摘要：鲑鱼虱Lepeophtheirus鲑海为患鳟褐鳟导致额外的海洋死亡率和行为改变，这可能导致海鳟种群减少。为了有效管理增加鲑鱼虱暴露的活动，例如鲑鱼养殖，有必要全面了解鲑鱼虱如何影响海鳟种群。因此，基于来自挪威北部哈尔瑟瓦河和阿尔塔菲尤德河系统的数据，开发了一个基于个体的模型（IBTRUTTA）来研究鲑鱼虱子侵染对海鳟种群数量和动力学的潜在影响。该模型可以研究虱子引起的死亡率的影响，还可以调查过早返回淡水的补偿性鲑鱼行为机制，该机制既可以持续越冬，也可以暂时过渡，然后海鳟可以回到海中。发现，在没有补偿机制的情况下，即使虱子侵染率较低，也可能导致海鳟丰度显着下降。补偿性行为机制有可能减少这些下降，但持续的过早返回导致返回成年人的体重减少。还显示了股票-招聘关系的形状会极大地影响虱子诱发的死亡率对人口的影响。