DataSheet_2_Atlantic cod (Gadus morhua) assessment approaches in the North and Baltic Sea: A comparison of environmental DNA analysis versus bottom trawl sampling.docx

The assessment of fish stocks is often dependent on scientific trawl fisheries surveys, which are both invasive and costly. The analysis of environmental DNA (eDNA) from water samples is regarded as a non-invasive and cost-effective alternative, but meaningful performance evaluations are required for a wider application. The goal of this study was to comparatively analyze a newly developed, more sensitive real-time PCR based eDNA approach with bottom trawl fisheries catches to locally detect and quantify Atlantic cod (Gadus morhua) in the North and Baltic Seas. With a species-specificity of the qPCR assay of 100%, a minimal limit of 15 Cytochrome b eDNA copies was determined for the detection of cod. In addition, a Gaussian processing regression proved a significant correlation (95%) between eDNA (copies per L of water) and cod biomass (CPUE/Ha) found by bottom trawling. The results presented here prove the potential of eDNA analyses for quantitative assessments of commercial fish stocks in the open ocean, although additional comparative analyses are needed to demonstrate its performance under different oceanographic conditions.

鱼类种群评估通常依赖于科学拖网渔业调查，但此类调查兼具侵入性与高成本属性。对水体样本中的环境DNA（environmental DNA, eDNA）进行分析被视为一种非侵入性且具备成本效益的替代方案，但要实现其更广泛的应用，仍需开展严谨的性能评估。本研究旨在将一种新开发的、灵敏度更高的基于实时荧光定量PCR（real-time PCR）的eDNA检测方法，与底拖网渔业捕捞数据进行对比分析，以在北海与波罗的海海域原位检测并定量大西洋鳕（Gadus morhua）。该qPCR检测方法的物种特异性达100%，其检测鳕鱼的最低限为15个细胞色素b（Cytochrome b）eDNA拷贝数。此外，高斯过程回归分析证实，水体eDNA拷贝数（单位：拷贝/升）与底拖网调查得到的鳕鱼生物量（单位：CPUE/Ha）之间存在95%置信度的显著相关性。尽管尚需开展更多对比分析以验证该方法在不同海洋水文条件下的表现，但本研究结果证实了eDNA分析在远洋商业鱼类种群定量评估中的应用潜力。