Winter survival of stream salmonid fishes and implications for population dynamics

冬季被认为是北温带淡水鱼类生存的关键时期。相对较少的工作集中在直接估计生存，特别是对补充和鱼类种群动态的影响。为了估计冬季生存，计划进行三个研究生项目。首先，我提出了一个问题：“鸡蛋的存活率是冬季严酷程度的函数吗？”“在新玩法的各种溪流中，将根据孵化环境（redd）的物理化学干扰（冰、溶解氧浓度）来确定野鸡蛋/alevin的存活率。为了回答“冬天是种群生存的瓶颈吗？“第二个项目的重点是野生大西洋鲑鱼幼鱼。基于成功的修改跟踪小鱼使用被动集成转发器（PIT）技术，具体目标将是区分冬季死亡率和迁移的parr跟踪PIT标记的parr在大河河段整个冬季和春季，并在响应干扰事件，如冻结和洪水。这些结果将形成模型的基础上，跨阶段的生存和相对重要性的环境和生物因素驱动鲑鱼种群动态。 加拿大大西洋地区的气候变化情景预测冬季降水增加，冬季中期分裂事件的可能性更高。这些变化可能会影响幼鼠的生存。然而，没有实验研究调查冬季排放事件和鲑鱼幼鱼的身体状况（和生存）之间的关系。这是第三个项目的重点。使用室外水箱和模拟的“洪水”事件在冬季，条件，能量含量，完成银化的能力，和三个年龄组的未成熟和成熟的幼仔的生存将被确定。拟议的研究具有强烈的保护重点，并试图确定自然环境压力（冰，可变流量）的影响，特别是因为这些压力可能会因气候变化情景而加剧（例如，冬季中期破裂）。研究结果应能增进对环境因素与生物区系之间关系的了解，以及我们保护处于危险中的人口的能力。

Winter is perceived as a critical period of survival for freshwater fishes in north temperate latitudes. Relatively little work has focused on direct estimates of survival and especially the influence on recruitment and fish population dynamics. To estimate winter survival, three graduate projects are planned. First, I address the question "Is egg survival a function of winter severity?" In various New Brunswick streams, wild egg/alevin survival will be determined in response to physico-chemical disturbance (ice, dissolved oxygen concentration) of the incubation environment (redd). To answer the question "Is winter a population survival bottleneck?" the focus of the second project will be on wild juvenile Atlantic salmon (parr). Based on successful modifications for tracking small fishes using passive integrated transponder (PIT) technology, the specific objective will be to distinguish between winter mortality and emigration of parr by tracking PIT-tagged parr in large river reaches throughout winter and spring and in response to disturbance events like freeze-up and flooding. These results will form the basis for modeling inter-stage survival and the relative importance of environmental and biological factors for driving salmon population dynamics. Climate change scenarios for Atlantic Canada predict increased winter precipitation, and a higher probability of mid-winter break-up events. Such changes may affect parr survival. However, no experimental studies have investigated the relationship between winter discharge events and body condition (and survival) of salmon parr. This is the focus of the third project. Using outdoor tanks and simulated 'flood' events over winter, the condition, energy content, ability to complete smoltification, and survival of three age-classes of immature and mature parr will be determined. The proposed research has a strong conservation focus and attempts to identify the effect of natural environmental stressors (ice, variable flows) especially as these stressors may be exacerbated by climate change scenarios (e.g., mid-winter break-ups). Results should improve understanding of the relationships between environmental factors and biota, and our ability to protect populations at risk.