marine environmental DNA
For metabarcoding analyses, polymerase chain reactions (PCRs) were performed to amplify the V4 region of the nuclear small ribosomal subunit (18S rRNA) and mitochondrial cytochrome c oxidase I (COI) genes. The primers for the 18S rRNA gene were Uni18SF: 5-AGG GCA AKY CTG GTG CCA GC-3 and Uni18SR: 5-GRC GGT ATC TRA TCG YCT T-3 (Zhan et al., 2013) and for COI: mlCOIintF: 5-GGW ACW GGW TGA ACW GTW TAY CCY CC-3 and jgHCO2198: 5-TAN ACY TCN GGR TGN CCR AAR AAY CA-3 (Leray et al., 2013). IlluminaTM overhang adaptors were attached to the primers to allow dual indexing as described in Kozich, Westcott, Baxter, Highlander, and Schloss (2013).