ABSTRACT: Salmon lice infestation is a challenge for wild post-smolt salmon during migration from their natal river to the sea in several regions of Norway. The traffic-light management system regulates growth in the aquaculture industry, where growth in production (6%) is only allowed if the impact of salmon lice on wild fish can be kept at a minimum and up to 10% mortality of wild salmonids are considered within the sustainability goal. We used a numerical ocean model, combined with an individual-based model for salmon lice, to evaluate the interannual variability in salmon lice concentrations in Production Zone 7, which was granted permission for production growth in 2017. Salmon lice releases were kept constant for 3 yr, while the physical conditions, e.g. wind and ocean circulation, varied. The total area of elevated lice infestations varied between 3.2 and 8.4% of the area within 5 km from the coast, due only to interannual physical variability mainly caused by variable wind patterns. Modeled post-smolts migrating out from the Namsen River (64.5°N, central Norway) towards the open ocean experienced mortality between 5 and 9%. Since Production Zone 7 was granted growth, we have simulated increased production and corresponding increases in lice releases. After 5 to 8 increments of 6% increase in production, the increase in salmon post-smolt mortality was of the same order of magnitude as the interannual variability. Information regarding migration route and time is crucial input to the model calculating post-smolt mortality, and inadequate information can affect the results significantly. These 2 methods (determining area of elevated lice infestations and estimating post-smolt mortality) provide complementary information and should be used in combination when the overall assessment of a production zone is made.

中文翻译：

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挪威自然条件的变化和未来水产养殖产量的增加对虱子侵染压力及其可持续性的影响

摘要：在挪威的几个地区，鲑鱼虱子的侵扰是野生鲑鱼从其出生的河流向海洋迁移过程中的一个挑战。交通灯管理系统调节着水产养殖业的增长，只有将鲑鱼虱对野生鱼类的影响保持在最低水平并考虑将野生鲑鱼的死亡率提高到10％的情况下，才允许产量增长（6％）在可持续发展目标内。我们使用了数值海洋模型，并结合了基于个体的鲑鱼虱子模型，来评估第7生产区鲑鱼虱子浓度的年际变化，该区域于2017年获准生产增长。鲑鱼虱子的释放量保持3不变年，而自然条件，例如风和海洋环流，却有所不同。虱子侵扰的总面积在距海岸5公里以内的面积的3.2％至8.4％之间变化，这仅是由于年际物理变化（主要由风型变化引起）引起的。从南森河（64.5°N，挪威中部）向公海迁移的模拟后软体动物死亡率为5％至9％。自从第7生产区获得增长以来，我们已经模拟了产量的增加以及虱子释放量的相应增加。在产量增加5％后增加5到8后，鲑鱼的熏鲑后死亡率增加与年际变化的数量级相同。有关迁徙路线和时间的信息是计算臭mol后死亡率的模型的关键输入，信息不足会严重影响结果。