To accommodate further growth in the Atlantic salmon aquaculture industry, new production sites may well be established at more exposed locations along the coast or even offshore. Here, fish will encounter strong currents and powerful waves, which are avoided at traditional sheltered locations. Exposed locations offer several advantages and necessitate new technological advancements. However, the most crucial question is whether Atlantic salmon are able to thrive in these more extreme environments. In this review, we describe how strong water currents affect the physiology, behaviour and ultimately the welfare of the fish. If ambient current speeds exceed swimming capacities, fish become fatigued and get stuck on the cage wall leading to unacceptable welfare. The swimming capacity will depend on both the magnitude and duration of the current speeds encountered. Moreover, several environmental and biological factors modulate swimming capabilities, where temperature, body size and health status are particularly important to consider. A series of empirical studies are subsequently used to formulate welfare guidelines with regard to biological limits in exposed aquaculture. In addition, owing to the growing popularity of cleaner fish in salmon aquaculture, we also evaluate their usefulness at exposed sites. Overall, Atlantic salmon is a powerful sustained swimmer, and based on available site surveys of ocean currents, we conclude that the prospects for responsible farming at exposed sites looks promising. However, cleaner fish species such as lumpfish and ballan wrasse are poor swimmers and are therefore not recommended for deployment at exposed sites.

中文翻译：

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海洋鲑鱼养殖中的鱼类福利

为了适应大西洋鲑鱼养殖业的进一步发展，很可能会在沿海甚至近海的更多裸露地点建立新的生产场所。在这里，鱼会遇到强大的水流和强大的海浪，而在传统的庇护所避免了这种情况。裸露的位置具有许多优势，因此需要新的技术进步。但是，最关键的问题是大西洋鲑鱼是否能够在这些更极端的环境中壮成长。在这篇综述中，我们描述了强烈的水流如何影响鱼类的生理，行为和最终的福祉。如果环境电流速度超过游泳能力，鱼就会变得疲劳并卡在笼壁上，从而导致无法接受的福利。游泳能力将取决于遇到的当前速度的大小和持续时间。此外，一些环境和生物因素会调节游泳能力，其中温度，体型和健康状况是特别重要的考虑因素。随后进行了一系列的经验研究，以制定关于裸露水产养殖生物极限的福利准则。此外，由于清洁鱼在鲑鱼养殖中的日益普及，我们还评估了其在裸露场所的有用性。总体而言，大西洋鲑是一个强大的持续性游泳者，根据现有的洋流现场调查，我们得出结论，在裸露地点进行负责任养殖的前景看起来很有希望。然而，