Simulating nutrient release from parental carcasses increases the growth, biomass and genetic diversity of juvenile Atlantic salmon

1. The net transport of nutrients by migratory fish from oceans to inland spawning areas has decreased due to population declines and migration barriers. Restoration of nutrients to increasingly oligotrophic upland streams (that were historically salmon spawning areas) have shown short-term benefits for juvenile salmon, but the longer-term consequences are little known. 2. Here we simulated the deposition of a small number of adult Atlantic salmon Salmo salar carcasses at the end of the spawning period in five Scottish upland streams (‘high parental nutrient’ treatment), while leaving five reference streams without carcasses (‘low parental nutrient’ treatment). All streams received exactly the same number of salmon eggs (n = 3,000) drawn in equal number from the same 30 wild-origin families, thereby controlling for initial egg density and genetic composition. We then monitored the resulting juvenile salmon and their macroinvertebrate prey, repeating the carcass addition treatment in the...

1. 由于种群数量下降与洄游障碍，洄游鱼类将营养物质从海洋输送至内陆产卵场的净运输量已有所减少。针对原本为鲑鱼产卵场的日益贫营养化（oligotrophic）高地溪流，恢复营养物质的措施已被证实可对幼鲑产生短期益处，但长期影响仍鲜为人知。2. 本研究在苏格兰的5条高地溪流的产卵期结束时，投放少量成年大西洋鲑（Salmo salar）鱼尸，设置为“高亲本营养”处理组；同时保留5条对照溪流不投放鱼尸，设置为“低亲本营养”处理组。所有溪流均投放等量鲑鱼鱼卵（n=3,000），且鱼卵均取自同一批30个野生起源家系，以此控制初始鱼卵密度与遗传组成。随后，我们对由此产生的幼鲑及其大型无脊椎动物猎物开展监测，并在……中重复了鱼尸添加处理。