Citizens of the Sea: Pacific Rally 2024 eDNA Metabarcoding Dataset

Paired-end sequencing was performed on Illumina NextSeq platforms across six sequencing runs. Bioinformatic processing used CUTADAPT and DADA2 for quality filtering and ASV generation, with taxonomic assignment against the SILVA, PR2, MIDORI and GenBank reference databases. After all quality filters, the final dataset comprised approximately 466 million high-quality reads and 34,197 unique amplicon sequence variants (ASVs) across 708 samples.The dataset documents a clear biogeographic gradient in community structure strongly correlated with sea surface temperature and chlorophyll-a concentration, the presence of putative harmful algal bloom (HAB)-forming microalgae and pathogenic bacteria across sampling latitudes, and the detection of 43 unique vertebrate taxa including five cetacean species, among them the IUCN Endangered sei whale (Balaenoptera borealis).This Darwin Core Sampling Event dataset contains 2,218 sampling events, 589,128 occurrence records, and extended measurement or fact (eMoF) records encoding read counts and target gene information per detection.

Field negative controls are excluded from occurrence data. Raw sequence data are available upon request to Citizens of the Sea. Data are managed in accordance with the FAIR and CARE data principles, national research permits, and the Nagoya Protocol on access and benefit sharing.