The Jinhaeman Bay, located in the South Sea of ​​Korea, is a well-known large-scale Pacific cod (Gadus macrocephalus) spawning ground where it migrates in the winter. We applied an eDNA approach to determine when G. macrocephalus migrates for spawning in the Jinhaeman Bay. We developed novel species-specific primers and minor groove binding (MGB) probe sets for quantitative PCR (qPCR) assays targeting the cytochrome b gene sequences. The cross-species test revealed that the assay not only detects the DNA of the target species but also detects low concentrations with high specificity. Moreover, the assay was also applied to water collected from the Jinhaeman Bay during the G. macrocephalus spawning season, and successful DNA amplification of the target species was confirmed. The assay was tested in silico, in vitro, and in vivo. Through these evaluations, the species specificity of the eDNA method for G. macrocephalus was confirmed, and this method was demonstrated to be useful for rapid assessment of the presence of this species. In particular, this method has been shown to be useful to determine when this species starts entering the spawning grounds and to characterize what its distribution is within the spawning grounds.

位于韩国南海的镇海万湾是著名的大型太平洋鳕鱼（Gadus macrocephalus）产卵地，冬季时这里是鳕鱼的洄游地。我们应用 eDNA 方法来确定G. macrocephalus何时迁移到 Jinhaeman 湾产卵。我们开发了新型物种特异性引物和小沟结合 (MGB) 探针组，用于针对细胞色素 b 基因序列的定量 PCR (qPCR) 测定。跨物种测试表明，该方法不仅可以检测目标物种的DNA，而且可以高特异性地检测低浓度。此外，该测定还适用于在G. macrocephalus期间从 Jinhaeman 湾收集的水。产卵季节，并确认目标物种的 DNA 扩增成功。该测定在计算机、体外和体内进行了测试。通过这些评估，证实了G. macrocephalus eDNA 方法的物种特异性，并且该方法被证明可用于快速评估该物种的存在。特别是，该方法已被证明可用于确定该物种何时开始进入产卵场并表征其在产卵场内的分布。