Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada.
Pacific Science Enterprise Centre, Fisheries and Oceans Canada, West Vancouver, British Columbia, Canada.
Mol Ecol. 2019 Mar;28(5):1138-1153. doi: 10.1111/mec.15007.
Current monitoring methods to assess benthic impacts of marine finfish aquaculture are based on complex biological indices and/or geochemistry data. The former requires benthic macrofauna morpho-taxonomic characterization that is time- and cost-intensive, while the latter provides rapid assessment of the organic enrichment status of sediments but does not directly measure biotic impacts. In this study, sediment samples were collected from seven stations at six salmon farms in British Columbia, Canada, and analyzed for geochemical parameters and by eDNA metabarcoding to investigate linkages between geochemistry and foraminifera. Sediment texture across farm sites ranged from sand to silty loam, while the maximum sediment pore-water sulphide concentration at each site ranged from 1,000 to 13,000 μM. Foraminifera alpha diversity generally increased with distance from cage edge. Adonis analyses revealed that farm site explained the most variation in foraminifera community, followed by sediment type, enrichment status, and distance from cage edge. Farm-specific responses were observed in diversity analyses, taxonomic difference analyses, and correlation analyses. Results demonstrated that species diversity and composition of foraminifera characterized by eDNA metabarcoding generated signals consistent with benthic biodiversity being impacted by finfish farming activities. This substantiates the validity of eDNA metabarcoding for augmenting current approaches to benthic impact assessments by providing more cost-effective and practicable biotic measures than traditional morpho-taxonomy. To capitalize on this potential, further work is needed to design a new nomogram that combines eDNA metabarcoding data and geochemistry data to enable accurate monitoring of benthic impacts of fish farming in a time- and cost-efficient way.
目前评估海水养殖鱼类对底栖生物影响的监测方法基于复杂的生物指数和/或地球化学数据。前者需要进行底栖大型动物形态分类学特征描述，这既耗时又昂贵，而后者则提供了沉积物有机富营养化状况的快速评估，但不能直接衡量生物影响。在这项研究中，从加拿大不列颠哥伦比亚省的六个鲑鱼养殖场的七个站点采集了沉积物样本，对地球化学参数和 eDNA 宏条形码进行了分析，以调查地球化学与有孔虫之间的联系。养殖场站点的沉积物质地从沙质到粉质壤土不等，而每个站点的最大沉积物孔隙水硫化物浓度从 1000 到 13000 μM 不等。有孔虫的 alpha 多样性通常随与笼边的距离增加而增加。Adonis 分析表明，养殖场站点对有孔虫群落的变异解释最多，其次是沉积物类型、富营养化状态和与笼边的距离。在多样性分析、分类差异分析和相关性分析中观察到了特定于养殖场的反应。结果表明，通过 eDNA 宏条形码生成的有孔虫物种多样性和组成特征信号表明，底栖生物多样性受到了鱼类养殖活动的影响。这证实了 eDNA 宏条形码在补充当前底栖影响评估方法方面的有效性，因为它提供了比传统形态分类学更具成本效益和实用性的生物措施。为了利用这一潜力，需要进一步的工作来设计一个新的列线图，该图将 eDNA 宏条形码数据和地球化学数据结合起来，以便以高效和节省成本的方式准确监测鱼类养殖对底栖生物的影响。
