Predation effects on juvenile Atlantic salmon (Salmo salar) populations in changing riverscape

河流景观变化中对幼年大西洋鲑鱼（Salmo salar）种群的捕食影响

• 批准号: RGPIN-2019-05964
• 负责人: Linnansaari, Tommi
• 金额: $ 2.77万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=687190
• 关键词: Predation; effects; juvenile; Atlantic; salmon

Natural processes, such as predation, are at play in all populations. Different anthropogenic actions (e.g. fisheries management, hydropower, climate change) may alter the effect that Atlantic salmon (Salmo salar) populations realize due to predation pressure. With many A. salmon populations threatened, any human-induced change may be detrimental. The field-based research proposed herein focuses on assessing effects of predation on juvenile A. salmon under three case situations in natural-flow and flow-regulated rivers.******The first project focuses on assessing a proposed trap-and-truck management strategy in a large hydropower regulated Saint John River (SJR), New Brunswick (NB). Our previous studies suggest late-autumn predation threat for pre-smolt A. salmon at the vicinity of a hydropower station. The validity of this hypothesis is examined by using novel predation-tag acoustic telemetry. Data on frequency and locations of predation events (from predation tags) will be combined with predator movement data from regular acoustic tags (striped bass Morone saxatilis and muskellunge Esox masquinongy) and the frequency of predation is examined as a function of water temperature.******The second project focuses on assessing the predation threat of expanded ( >1 million) striped bass population on A. salmon smolts in the Miramichi River, NB. Project will quantify predation by different size categories of striped bass in time and space throughout the smolt migration window, and combine these data with the total daily run size of A. salmon smolts to reveal a potential predation threat by size category. The information will be used to revise fisheries management advice within bass fishery.******The third project will A) compare seasonal levels of predation by semiaquatic mammals in wadable streams with contrasting ice-regimes (i.e. ice-free and ice covered) and B) examine the established hypothesis that threat of predation is the driving force of cessation of daytime activity in cold water temperature in juvenile A. salmon. Both research components rely on new developments in Passive Integrated Transponder technology for tracking juvenile A.salmon. Field research for project P3A will be undertaken in small streams in NB where ice processes are known based on previous research. Project P3B will occur in the Kapisillit River in Greenland; the only stream in the world where an A. salmon population has evolved in the absence of mammalian predation. Winter behavior of A. salmon is therefore expected to reflect different activity patterns than in populations where winter predation has evolutionarily been present.******The proposed research will contribute novel information regarding the role of predation in regulating A. salmon populations in seasonal small nursery streams in changing climate, and will provide advice that is directly applicable for better managing threatened and socio-economically important A. salmon populations in significant North American salmon rivers.

自然过程，例如捕食，在所有种群中都在发挥作用。不同的人类活动（例如渔业管理、水力发电、气候变化）可能会改变大西洋鲑鱼（Salmo salar）种群因捕食压力而实现的影响。由于许多鲑鱼种群受到威胁，任何人类引起的变化都可能是有害的。本文提出的实地研究重点是评估在自然流量和流量调节河流的三种情况下捕食对幼鲑鱼的影响。******第一个项目重点是评估拟议的诱捕和-新不伦瑞克省 (NB) 的圣约翰河 (SJR) 大型水电监管卡车管理策略。我们之前的研究表明，晚秋时节，水电站附近的小鲑鱼面临着捕食威胁。通过使用新型捕食标签声学遥测技术来检验该假设的有效性。捕食事件的频率和位置数据（来自捕食标签）将与来自常规声学标签（条纹鲈 Morone saxatilis 和 muskellunge Esox masquinongy）的捕食者运动数据相结合，并根据水温的函数检查捕食频率。 ** ****第二个项目的重点是评估米拉米奇河中条纹鲈鱼数量的增加（>100万）对鲑鱼小鲑鱼的捕食威胁，注意。该项目将量化整个小鲑鱼迁徙窗口中不同体型的条纹鲈鱼在时间和空间上的捕食情况，并将这些数据与鲑鱼小鲑鱼的每日总游动规模相结合，以揭示按体型类别划分的潜在捕食威胁。这些信息将用于修订鲈鱼渔业中的渔业管理建议。******第三个项目将 A) 比较可涉水溪流中半水生哺乳动物的季节性捕食水平与对比冰区（即无冰和冰覆盖） ) 和 B) 检查已建立的假设，即捕食威胁是幼鱼在冷水温度下停止白天活动的驱动力。这两个研究部分都依赖于无源集成转发器技术的新发展来跟踪鲑鱼幼鱼。 P3A 项目的实地研究将在新罕布什尔州的小溪流中进行，根据先前的研究，那里的冰过程是已知的。 P3B项目将发生在格陵兰岛的卡皮西利特河；世界上唯一一条鲑鱼种群在没有哺乳动物捕食的情况下进化的河流。因此，预计鲑鱼的冬季行为将反映与进化上存在冬季捕食的种群不同的活动模式。******拟议的研究将提供关于捕食在调节鲑鱼种群中的作用的新信息。气候变化中的季节性小苗圃溪流，并将提供直接适用于更好地管理北美重要鲑鱼河流中受威胁和具有社会经济重要性的鲑鱼种群的建议。