A major trend in marine aquaculture is to move production to more exposed sites with occasionally rough ocean current events. However, it is unclear whether fish will thrive in these extreme environments, since thorough descriptions of ambient current conditions with regards to fish welfare is lacking. In the present study, ocean current data were collected using acoustic Doppler current profilers at 5 exposed sites along the Norwegian coast over minimum periods of 5 mo. To evaluate welfare risks, current data was compared to known limits of swimming capabilities, such as onset of behavioural changes and critical swimming speeds (Ucrit), of Atlantic salmon Salmo salar and lumpfish Cyclopterus lumpus. Specifically, at each site, current speeds were classified into 6 categories based on expected impact on swimming behaviours of Atlantic salmon, and duration of currents within each category were inspected using a homogeneous and non-homogeneous criterion for the water column. Current speeds were then compared with projected Ucrit at relevant temperatures and fish sizes of Atlantic salmon and lumpfish. Furthermore, a detailed characterization of extreme events at the most exposed site was performed. Of the 5 locations, only 1 exceeded the Ucrit of Atlantic salmon, while all sites featured currents above Ucrit of lumpfish for up to 33 h at a time. These results suggest that responsible Atlantic salmon farming is possible at sites considered exposed, while lumpfish should be restricted to more sheltered environments. The presented method can be applied for other aquaculture fish species if adequate data are available.

中文翻译：

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基于鱼类福利的水产养殖场海流速度分类方法

海水养殖的一个主要趋势是将生产转移到更暴露的地点，偶尔会有汹涌的洋流事件。然而，目前尚不清楚鱼类是否会在这些极端环境中茁壮成长，因为缺乏对鱼类福利的环境电流条件的全面描述。在本研究中，使用声学多普勒海流剖面仪在挪威海岸沿线的 5 个暴露地点在最短 5 个月的时间内收集了洋流数据。为了评估福利风险，将当前数据与已知的游泳能力限制进行了比较，例如大西洋鲑鱼 Salmo salar 和鲽鱼的行为变化和临界游泳速度 (Ucrit) 的开始。具体来说，在每个站点，根据对大西洋鲑鱼游泳行为的预期影响，当前速度分为 6 类，使用均匀和非均匀的水柱标准检查每个类别内的电流和持续时间。然后将当前速度与大西洋鲑鱼和鲽鱼在相关温度和鱼大小下的预测 Ucrit 进行比较。此外，还对最暴露地点的极端事件进行了详细描述。在这 5 个地点中，只有 1 个地点超过了大西洋鲑鱼的 Ucrit，而所有地点的水流都一次超过 33 小时。这些结果表明，负责任的大西洋鲑鱼养殖在被认为是暴露的地点是可能的，而块鱼应该限制在更隐蔽的环境中。如果有足够的数据，所提出的方法可以应用于其他水产养殖鱼类。