Periods of fasting occur for a multitude of reasons in Atlantic salmon aquaculture. Feed withdrawal is widely used prior to transport, parasite treatments, preslaughter and for depuration purposes in recirculating aquaculture systems. Voluntary fasting is a coping response when fish have poor health or are exposed to poor farm environments. Owing to increased attention to animal welfare in aquaculture, concerns have been raised regarding ethical issues when farmed fish are subjected to fasting. However, thorough science‐based recommendations for fasting and feed‐withdrawal regimes have been lacking. The purpose of this review is to provide a synthesis of the various causes for fasting in Atlantic salmon aquaculture and evaluate their associated welfare implications so that guidelines for appropriate practices can be formulated. To interpret impacts, we describe biological responses and tolerance limits to fasting in Atlantic salmon and consider adaptations in the wild. Fry and parr are highly sensitive to feed withdrawal. However, post‐smolts and adults are well‐adapted to endure prolonged fasting without experiencing compromised functionality or health. Here, short periods of feed withdrawal prior to operations should therefore not constitute significant welfare concerns. Serious concerns are instead associated with voluntary fasting that may continue for weeks. We emphasize that environmental extremes that exceed appetite impairing thresholds must be avoided. Additionally, farmed fish should not be subjected to practices that lead to chronic stress that induce cessation of appetite. Diseases or parasites that impair appetite should also be mitigated. Fasting is here a symptom rather than a cause for poor welfare.

中文翻译：

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禁食及其对大西洋鲑鱼养殖中鱼类福利的影响

在大西洋鲑鱼养殖中，出于多种原因会出现禁食期。饲料停料广泛用于运输、寄生虫处理、屠宰前以及循环水产养殖系统中的净化目的。当鱼类健康状况不佳或暴露在恶劣的养殖环境中时，自愿禁食是一种应对反应。由于人们越来越关注水产养殖中的动物福利，人们对养殖鱼类禁食时的道德问题提出了担忧。然而，缺乏针对禁食和停食方案的全面的、基于科学的建议。本次审查的目的是综合分析大西洋鲑鱼养殖中禁食的各种原因，并评估其相关的福利影响，以便制定适当的做法指南。为了解释影响，我们描述了大西洋鲑鱼对禁食的生物反应和耐受限度，并考虑了野外的适应。鱼苗和帕尔对断食高度敏感。然而，小幼崽和成年人很适合忍受长时间的禁食，而不会出现功能或健康受损的情况。因此，操作前的短期停料不应构成重大的福利问题。相反，严重的担忧与可能持续数周的自愿禁食有关。我们强调，必须避免超过食欲损害阈值的极端环境。此外，养殖鱼类不应受到导致慢性应激而导致食欲停止的做法。损害食欲的疾病或寄生虫也应该得到缓解。在这里，禁食是一种症状，而不是福利不佳的原因。