ABSTRACT: The regulation of aquaculture production in Norway considers the potential impact of salmon lice on wild fish. However, most attention has been focused on impacts on wild Atlantic salmon, despite the fact that anadromous brown trout spend the majority of their marine phase in coastal waters, where salmon lice have the highest impact. In the present study, we first suggest changes in marine living area and marine feeding time as sustainability indicators for first-time migrant sea trout, as high salmon lice densities may exclude sea trout from otherwise usable habitat and force them to return early to freshwater. Further, a method based on a bio-hydrodynamic model was developed to serve as a proxy for these indicators. The method accounted for the size, migration timing and spatial extent of sea trout and was demonstrated in 2 Norwegian salmon aquaculture production areas, Hardangerfjord (PO3) and Romsdalsfjord (PO5), and 2 focal rivers from within each fjord. Based on these comparisons, we exemplify how the change in marine living area and marine feeding time differed between PO3 and PO5 and within the areas. Sea trout migrating to sea late (June 5) were always more affected by lice than those migrating early (April 24) or at intermediate dates (May 15). Our estimates revealed dramatic potential impacts of salmon lice on sea trout populations, which were greatly influenced by spatial and temporal aspects. Considering the negative impacts of salmon lice on sea trout, a holistic view of environmental interactions between aquaculture and wild species that depend on habitats exploited for production is necessary.

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开发用于养殖的沿海地区海鳟的风险评估方法

摘要：挪威的水产养殖生产法规考虑了鲑鱼虱对野生鱼类的潜在影响。但是，尽管事实上褐鳟鳟鱼的大部分海相都栖息在沿海地区，鲑鱼虱子的影响最大，但大多数注意力都集中在对野生大西洋鲑鱼的影响上。在本研究中，我们首先建议将海洋生活区域和海洋取食时间的变化作为首次迁徙海鳟的可持续性指标，因为高鲑鱼虱子密度可能会将海鳟排除在其他可利用的栖息地之外，并迫使它们早日返回淡水。此外，开发了一种基于生物流体动力学模型的方法来替代这些指标。该方法占了大小，鳟鱼的迁移时间和空间范围在挪威的两个鲑鱼养殖产区，哈当厄尔峡湾（PO3）和罗姆斯达尔峡湾（PO5）以及每个峡湾中的2条重点河流中得到了证明。基于这些比较，我们举例说明了PO3和PO5之间以及该区域内海洋生活区域和海洋觅食时间的变化是如何不同的。迁移到海底（6月5日）的海鳟比起早期（4月24日）或中期（5月15日）迁移的海虱受虱子的影响更大。我们的估计揭示了鲑鱼虱对海鳟种群的巨大潜在影响，这在很大程度上受到时空方面的影响。考虑到鲑鱼虱对鳟鱼的不利影响，