Expanded <scp>28S rRNA</scp> Dataset for Environmental <scp>DNA</scp> Detection of Mesophotic and Deep‐Sea Octocorals in the Western Pacific

ABSTRACT Environmental DNA (eDNA) metabarcoding is rapidly becoming an effective tool for biodiversity assessments. However, for taxa such as mesophotic and deep‐sea octocorals, which are difficult to classify based on morphological and molecular grounds and are logistically challenging to sample using conventional SCUBA diving, accurately identified and curated specimens in biological repositories remain under‐represented. This limitation reduces the availability of reliable reference sequences for eDNA detection. Mesophotic and deep‐sea octocorals are key components of mesophotic and cold‐water coral ecosystems that occur at depths &gt; 30 m. Because these habitats are highly vulnerable to anthropogenic disturbances, the ability to monitor them effectively is imperative. This study aimed to expand the 28S rRNA reference database for mesophotic and deep‐sea octocorals in the western Pacific Ocean. A total of 269 samples were sequenced using either Sanger sequencing or low‐coverage genome skimming. Based on expert morphological identifications, the dataset comprised 52 genera spanning 24 families and two orders. Detailed metadata for all samples are provided, including DDBJ accession numbers, sampling locations, depths, collection dates, and repository information. These resources will strengthen biodiversity monitoring and support the conservation of mesophotic and cold‐water coral ecosystems. The detailed metadata and complete dataset are available in MetaCat in JaLTER at https://doi.org/10.20783/DIAS.JLE.91 .