ABSTRACT: Whilst aquaculture continues its global expansion, containment of fish in sea cages remains a persistent environmental challenge. Within Atlantic salmon Salmo salar farming, widespread escapes over several decades have left a legacy of ecological and genetic impacts on wild populations. Quantifying the characteristics of escapees, and how they vary in time and space, is important to understand how environmental impacts will vary and how mitigation strategies need to be tuned. Using a fish trap located in the River Etne on the west coast of Norway, we created an ecological and genetic profile for 616 escapees entering the river. The most important findings of the present study were (1) the annual number of escapees entering the trap declined in the period 2014-2018; (2) more than half of the escapees entering the river were mature; (3) the vast majority of escapees entering the river were categorised as recent escapees; (4) nearly all (96%) of the early escapees were mature upon entry to the river, while just over half (55%) of the recent escapees were mature; and (5) the escapees originated from multiple sources every year. We conclude that without the fish trap, this population would have been at risk of exposure to further spawning and introgression of domesticated salmon. Furthermore, the current findings of maturation status and escape history highlight the fact that mitigation efforts to reduce escape of smolts, post-smolts and larger fish all need continued attention from the management authorities and aquaculture industry.

中文翻译：

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落入陷阱：2014-2018年期间从野生产卵种群中移走的养殖大西洋鲑鱼中有一半以上已经成熟

摘要：虽然水产养殖继续在全球扩张，但将鱼类限制在海水网箱中仍然是一个持续存在的环境挑战。大西洋鲑鱼Salmo salar内随着农业的发展，几十年来广泛的逃亡给野生种群留下了生态和遗传影响。量化逃亡者的特征以及他们在时间和空间上的变化对于了解环境影响如何变化以及需要如何调整缓解策略非常重要。我们利用位于挪威西海岸埃特纳河的鱼陷阱，为 616 名进入河流的逃亡者创建了生态和基因档案。本研究最重要的发现是：（1）2014-2018年期间，每年进入陷阱的逃亡者数量有所下降；（二）入河逃亡者一半以上为成年；（三）入河逃亡者绝大多数属于近期逃亡者；(4) 几乎所有（96%）的早期逃亡者在进入河流时都已成熟，而最近逃亡者中只有一半以上（55%）是成熟的；（5）每年逃亡者的来源有多种。我们的结论是，如果没有鱼陷阱，这个种群将面临进一步产卵和驯化鲑鱼渗入的风险。此外，目前对成熟状况和逃逸历史的调查结果突显了这样一个事实：减少小鲑鱼、小鲑鱼和较大鱼类逃逸的缓解努力都需要管理当局和水产养殖业的持续关注。