Abstract：
Physical enrichment can improve the welfare of captive fish. Previous research has shown that fish often show preference for enriched environments, which can also result in improvements in growth performance. However, effects of enrichment are not always positive and the design and extent of the enrichment needs to be carefully considered. In this regard, information in real aquaculture scenarios is limited. The aim of this study was to serve as a proof of concept to test the feasibility of using simple PVC immersed shelters as a tool for better welfare in an organic rainbow trout farm. Our shelters induced little extra work in farm routines and had no negative effects on fish performance, health or mortality. The behavioral assessment pointed to a preference for sheltered areas in undisturbed conditions. However, no benefits were observed in terms of stress responses during standardized stress tests, and fish showed no obvious shelter-seeking behavior after disturbance. The results in terms of shelter-seeking behavior were probably limited by the short duration of the experiment, which was due to the farm\'s routines and needs. It is recommended that strategies for enrichment in real scenarios should be tested covering a relevant part of the life cycle of the fish in captivity, to fully account for their potential to improve welfare in aquaculture.
摘要：
物理富集可以提高圈养鱼的福利。先前的研究表明，鱼类通常表现出对丰富环境的偏好，这也可以导致增长绩效的提高。然而,富集的效果并不总是积极的，需要仔细考虑富集的设计和程度。在这方面,真实水产养殖场景中的信息是有限的。这项研究的目的是作为概念证明，以测试在有机虹鳟鱼养殖场中使用简单的PVC浸入式庇护所作为更好福利的工具的可行性。我们的庇护所在农场常规中几乎没有额外的工作，并且对鱼类的表现没有负面影响，健康或死亡率。行为评估指出，在不受干扰的条件下，人们倾向于庇护地区。然而,在标准化压力测试期间，在应激反应方面没有观察到任何好处，鱼在受到干扰后没有明显的寻求庇护行为。在寻求庇护行为方面的结果可能受到实验持续时间短的限制，这是由于农场的常规和需要。建议应测试实际情况下的富集策略，涵盖圈养鱼类生命周期的相关部分，充分考虑到它们改善水产养殖福利的潜力。
