Marine Epidemiology

全球鱼类生产正处于从渔业到水产养殖的过渡阶段。一些沿海海域现在被管理用于水产养殖生产，在那里，驯养鱼类种群可以与野生鱼类交换传染病。野生动物和驯养动物之间寄生虫传播（从病毒到外寄生桡足类）的加剧是传染病出现的主要危险因素。随着水产养殖规模的扩大，养殖鱼类的疾病也随之出现，并已成为渔业和养护面临的挑战。拟议的研究有四个相互关联的项目：******项目1是对全球鱼类疾病出现模式的荟萃分析。在野生脊椎动物中，鱼类的疾病发生率最高，大多数病例涉及以驯养鱼类为主要原因的传播。这意味着野生鱼类的疾病出现与驯化形式有关，但不清楚其风险与水产养殖类型、疾病因子特征、环境因素以及生态和进化机制有关。这项研究将量化这些因素导致疾病出现的风险水平。******项目2涉及野生鱼类和养殖鱼类之间疾病相互作用的理论建模，包括疾病传播的生态特征、毒性和耐药性的进化变化以及管理因素。我们将建立和分析数学模型，以评估这些过程的相对贡献，以表征可持续渔业和水产养殖可以运作的参数空间。这些结果将为了解沿海地区传染病的出现提供一个新的框架，可以应用于多种情况。******项目3包括实地调查，将评估加拿大最有价值的野生鲑鱼种群在加拿大最多产的鲑鱼养殖区迁徙路线上的感染风险。野外考察将采用多阶段过滤和定量分子分析（qPCR）技术，分析野生鲑鱼幼鱼洄游路线沿线海水中的感染性微生物群落，定量分析可感染野生鲑鱼幼鱼的30种不同寄生虫（从病毒到桡足类）的分布。******项目4将对孵化场中饲养的经药物处理和对照组的幼鱼进行对照实验，以评估保护野生幼鱼不受细菌和甲壳类寄生虫侵害在多大程度上可以提高成年鲑鱼的回报。这些实验将提供多物种寄生对野生鱼类在处理和招募之间进行海洋迁移的招募过程中的作用的现场数据。这些数据将对加拿大水产养殖的科学和政策具有重要意义，并提供对自然宿主-寄生虫系统整体的罕见见解。**

Global fish production is in a transition from fisheries to aquaculture. Some coastal seas are now managed for aquaculture production, where populations of domesticated fish can exchange infectious diseases with wild fish. The intensification of parasite transmission (ranging from viruses to ectoparasitic copepods) between wild and domesticated animals is a primary risk factor or the emergence of infectious diseases. Diseases of farmed fish have emerged concurrently with aquaculture expansion, and have become a challenge also for fisheries and conservation. The proposed research has four interrelated projects:******Project 1 is a meta-analysis of global patterns of disease emergence in fish. Across wild vertebrates, fishes have the highest rates of disease emergence, and most cases involve transmission with domesticated fishes as a primary cause. This implies that disease emergence in wild fish is tied to forms of domestication, but it is not clear the risks in relation to types of aquaculture, characteristics of disease agents, environmental factors, and ecological and evolutionary mechanisms. The research will quantify the level of risk of these factors for disease emergence.******Project 2 involves theoretical modelling of disease interactions between wild and farmed fish, including ecological features of disease transmission, evolutionary changes in virulence and drug resistance, and management factors. We will build and analyze mathematical models to evaluate the relative contributions of these processes to characterize the parameter space within which sustainable fisheries and aquaculture can operate. The results will provide a new framework for understanding the emergence of infectious diseases in coastal seas that can be applied to multiple situations.******Project 3 involves fieldwork that will evaluate the infection risks to Canada's most valuable populations of wild salmon along migration routes through the Canada's most productive salmon farming areas. The fieldwork will analyze the infectious microbial communities in seawater at locations along wild juvenile salmon migration routes using a multi-stage filtration process and quantitative molecular analysis (qPCR) to quantify the distribution of 30 different species of parasites (viruses to copepods) that can infect wild juvenile salmon. ******Project 4 will conduct controlled experiments using drug treated and control groups of juvenile fish raised in a hatchery to assess the extent to which protecting wild juvenile salmon from bacterial and crustacean parasites can improve returns of adult salmon. These experiments will provide in-situ data on the role of parasitism by multiple species on the recruitment for a wild fish with an oceanic migration between treatment and recruitment. The data will be of importance to Canadian science and policy on aquaculture, and give a rare insight into natural host-parasite systems overall. **