The starfish Asterias amurensis, a well-known predator of molluscan species in intertidal ecosystems, has caused substantial ecological and economic losses in North China such as offshore Qingdao. Effective monitoring and prevention measures are urged to minimize its negative impacts. Compared with traditional biomonitoring methods, environmental DNA technology has emerged as a powerful and cost-efficient tool for inferring species’ presence and abundance. In this study, we developed a pair of species-specific primers (i.e., Ast-F and Ast-R) for the A. amurensis mitochondrial COI gene and tested its utility in amplifying and quantifying the DNA fragments from environmental samples under both laboratory and field conditions. The results of controlled water tank experiments demonstrated that the amount of eDNA released by A. amurensis was positively related to its biomass; after the removal of the starfish, the eDNA degraded significantly in 24 h and remained detectable for 8 days. The number of eDNA copies enriched tended to increase with smaller pore size of filter membrane and larger volume of filtered water. For field tests, we confirmed the validation of our approach in six locations in Qingdao by filtering 1000 ml water per sample with a 0.45-µm pore size filtration. All the amplification products generated a single and bright band via gel electrophoresis, and the quantitative PCR results unveiled significant differences in eDNA copies. This study provided an eDNA-based approach for investigating the distribution and biomass of A. amurensis, which may help to formulate early warning and management strategies in coastal Qingdao and other regions.

海星是潮间带生态系统中著名的软体动物捕食者，它在青岛近海等华北地区造成了巨大的生态和经济损失。敦促采取有效的监测和预防措施，尽量减少其负面影响。与传统的生物监测方法相比，环境 DNA 技术已成为推断物种存在和丰度的强大且经济高效的工具。在本研究中，我们开发了一对针对山梨线粒体COI基因的物种特异性引物（即Ast-F和Ast-R），并在实验室和环境下测试了其在扩增和定量环境样本中的DNA片段方面的效用。现场条件。控制水箱实验结果表明，山梨释放的eDNA量与其生物量呈正相关；去除海星后，eDNA 在 24 小时内显着降解，并在 8 天内保持可检测。随着滤膜孔径的减小和过滤水体积的增大，富集的 eDNA 拷贝数趋于增加。对于现场测试，我们通过使用 0.45 µm 孔径过滤器过滤每个样品 1000 毫升的水，确认了我们的方法在青岛的六个地点的验证。所有扩增产物通过凝胶电泳均产生单一且明亮的条带，定量PCR结果揭示了eDNA拷贝数的显着差异。本研究为研究山梨的分布和生物量提供了一种基于eDNA的方法，有助于制定青岛沿海及其他地区的早期预警和管理策略。